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Sample records for ge process

  1. Study of Ge loss during Ge condensation process

    International Nuclear Information System (INIS)

    Xue, Z.Y.; Di, Z.F.; Ye, L.; Mu, Z.Q.; Chen, D.; Wei, X.; Zhang, M.; Wang, X.

    2014-01-01

    Ge loss during Ge condensation process was investigated by transmission electron microscopy, Raman spectroscopy, secondary ion mass spectrometry and Rutherford backscattering spectrometry. This work reveals that Ge loss can be attributed to the Ge oxidation at SiO 2 /SiGe interface, Ge diffusion in SiO 2 layers and Ge trapped at buried SiO 2 /Si interface. During Ge condensation process, with the increase of the Ge content, the Si atoms become insufficient for selective oxidation at the oxide/SiGe interface. Consequently, the Si and Ge are oxidized simultaneously. When the Ge composition in SiGe layer increases further and approaches 100%, the Ge atoms begin to diffuse into the top SiO 2 layer and buried SiO 2 layer. However, the X-ray photoelectron spectrometry analysis manifests that the chemical states of the Ge in top SiO 2 layer are different from those in buried SiO 2 layer, as the Ge atoms diffused into top SiO 2 layer are oxidized to form GeO 2 in the subsequent oxidation step. With the increase of the diffusion time, a quantity of Ge atoms diffuse through buried SiO 2 layer and pile up at buried SiO 2 /Si interface due to the interfacial trapping. The SiO 2 /Si interface acts like a pump, absorbing Ge from a Ge layer continuously through a pipe-buried SiO 2 layer. With the progress of Ge condensation process, the quantity of Ge accumulated at SiO 2 /Si interface increases remarkably. - Highlights: • Ge loss during Ge condensation process is attributed to the Ge oxidation at SiO 2 /SiGe interface. • Ge diffusion in SiO 2 layers and Ge trapped at buried SiO 2 /Si interface • When Ge content in SiGe layer approaches 100%, Ge diffusion into the SiO 2 layer is observed. • Ge then gradually diffuses through buried SiO 2 layer and pile up at SiO 2 /Si interface

  2. The coarsening process of Ge precipitates in an Al-4 wt.% Ge alloy

    Energy Technology Data Exchange (ETDEWEB)

    Deaf, G.H

    2004-05-01

    In this paper the results of a quantitative transmission electron microscopy (TEM) investigation of the precipitation process of Ge in an Al-4 wt.% Ge alloy are described. Two crystallographic orientation relationships between the irregular germanium precipitate and aluminum matrix were found to be [1 0 0]{sub Ge} || [1 1 0]{sub Al} and [1 1 4]{sub Ge} || [1 0 0]{sub Al}. The irregular germanium precipitates formed on [0 0 1]{sub Al} habit planes. The origin of the irregular shape is due to the existence of a highly anisotropic interfacial energy as well as in an isotropic growth rate along <1 1 0>{sub A1} directions. Particles sizes were determined for variety of isothermal ageing times at 348, 423 and 523 K. The coarsening of the different morphologies of Ge precipitates was found to obey Ostwald ripening kinetics. The TEM results showed that the coarsening of irregular particles was due to the interfacial coalescence between these particles. Nine different morphologies have been distinguished in the form of (i) irregular particles, (ii) spheres, (iii) hexagonal plates, (iv) rods, (v) triangular plates, (vi) laths, (vii) small tetrahedra, (viii) rectangular plates, and (ix) Lamellae shape.

  3. Interfacial processes in the Pd/a-Ge:H system

    Science.gov (United States)

    Edelman, F.; Cytermann, C.; Brener, R.; Eizenberg, M.; Weil, R.; Beyer, W.

    1993-06-01

    The kinetics of phase transformation has been studied in a two-layer structure of Pd/a-Ge:H after vacuum annealing at temperatures from 180 to 500°C. The a-Ge:H was deposited at 250°C on both c-Si and cleaved NaCl substrates in an RF glow discharge from a GeH 4/H 2 mixture. It was found that, similarly to the Pd/c-Ge and the Pd/a-Ge (e-gun deposited) systems, in the case of 0.15-0.2 μm Pd/0.6-1.0 μm a-Ge:H interfacial germanides formed first through the production of Pd 2Ge (plus a small amount of PdGe), and then PdGe was produced. The growth of both compounds was found to be diffusion-controlled. The nonreacted a-Ge:H layer beneath the germanide overlayer crystallized at 400-500°C. A reverse sequence of germanides formation was revealed in the case of 50 nm Pd/30 nm a-Ge:H, studied by in situ heat treatment in the TEM utilizing non-supported samples. The first germanide detected was PdGe and then, as a result of PdGe and Ge reaction or the PdGe decomposition, Pd 2Ge formed. The temperature dependence of the incubation time before the first ˜ 10 nm PdGe grains formed, followed an Arrhenius curve with an activation energy of 1.45 eV.

  4. Assembly of Ge nanocrystals on SiO2 via a stress-induced dewetting process

    International Nuclear Information System (INIS)

    Sutter, E; Sutter, P

    2006-01-01

    We use epitaxial Ge islands on silicon-on-insulator (001) to initiate and drive the dewetting of the ultrathin ( 2 layer and transforms the Ge islands into oxide-supported, electrically isolated, Ge-rich nanocrystals. We investigate the process of dewetting and demonstrate that it can be used for the controlled assembly of nanocrystals-from isolated single ones to dense arrays

  5. Growth and relaxation processes in Ge nanocrystals on free-standing Si(001) nanopillars.

    Science.gov (United States)

    Kozlowski, G; Zaumseil, P; Schubert, M A; Yamamoto, Y; Bauer, J; Schülli, T U; Tillack, B; Schroeder, T

    2012-03-23

    We study the growth and relaxation processes of Ge crystals selectively grown by chemical vapour deposition on free-standing 90 nm wide Si(001) nanopillars. Epi-Ge with thickness ranging from 4 to 80 nm was characterized by synchrotron based x-ray diffraction and transmission electron microscopy. We found that the strain in Ge nanostructures is plastically released by nucleation of misfit dislocations, leading to degrees of relaxation ranging from 50 to 100%. The growth of Ge nanocrystals follows the equilibrium crystal shape terminated by low surface energy (001) and {113} facets. Although the volumes of Ge nanocrystals are homogeneous, their shape is not uniform and the crystal quality is limited by volume defects on {111} planes. This is not the case for the Ge/Si nanostructures subjected to thermal treatment. Here, improved structure quality together with high levels of uniformity of the size and shape is observed.

  6. Exclusive processes at JLab at 6 GeV

    Directory of Open Access Journals (Sweden)

    Kim Andrey

    2015-01-01

    Full Text Available Deeply virtual exclusive reactions provide a unique opportunity to probe the complex internal structure of the nucleon. They allow to access information about the correlations between parton transverse spatial and longitudinal momentum distributions from experimental observables. Dedicated experiments to study Deeply Virtual Compton Scattering (DVCS and Deeply Virtual Meson Production (DVMP have been carried out at Jefferson Lab using continuous electron beam with energies up to 6 GeV. Unpolarized cross sections, beam, target and double spin asymmetries have been measured for DVCS as well as for π0 exclusive electroproduction. The data from Hall B provide a wide kinematic coverage with Q2=1-4.5 GeV2, xB=0.1-0.5, and −t up to 2 GeV2. Hall A data have limited kinematic range partially overlapping with Hall B kinematics but provide a high accuracy measurements. Scaling tests of the DVCS cross sections provide solid evidence of twist-2 dominance, which makes chiral-even GPDs accessible even at modest Q2. We will discuss the interpretation of these data in terms of Generalized Parton Distributions (GPDs model. Successful description of the recent CLAS π0 exclusive production data within the framework of the GPD-based model provides a unique opportunity to access the chiral-odd GPDs.

  7. Processing and characterization of new oxysulfide glasses in the Ge-Ga-As-S-O system

    International Nuclear Information System (INIS)

    Maurel, C.; Petit, L.; Dussauze, M.; Kamitsos, E.I.; Couzi, M.; Cardinal, T.; Miller, A.C.; Jain, H.; Richardson, K.

    2008-01-01

    New oxysulfide glasses have been prepared in the Ge-Ga-As system employing a two-step melting process which involves the processing of the chalcogenide glass (ChG) and its subsequent melting with amorphous GeO 2 powder. Optical characterization of the synthesized oxysulfide glasses has shown that the cut-off wavelength decreases with increasing oxygen content, and this has been correlated to results of Raman and infrared (IR) spectroscopies which show the formation of new oxysulfide structural units. X-ray photoelectron spectroscopy (XPS) analysis to probe the bonding environment of oxygen atoms in the oxysulfide glass network, has revealed the preferred formation of Ga-O and Ge-O bonds in comparison to As-O bonds. This work has demonstrated that melting a ChG glass with GeO 2 leads to the formation of new oxysulfide glassy materials. - Graphical abstract: In this paper, we explain how new oxysulfide glasses are prepared in the Ge-Ga-As system employing a two-step process: (1) the processing of the chalcogenide glass (ChG) and (2) the re-melting of the ChG with GeO 2 powder. Raman, infrared and XPS spectroscopies show the formation of new oxysulfide structural units

  8. Thick-film processing of Pb5Ge3O11-based ferroelectric glass-ceramics

    International Nuclear Information System (INIS)

    Cornejo, I.A.; Haun, M.J.

    1996-01-01

    Processing techniques were investigated to produce c-axis orientation, or texture, of ferroelectric Pb 5 Ge 3 O 11 -based glass-ceramic compositions during crystallization of amorphous thick-film printed samples from the Pb 5 Ge 3 O 11 -PbTiO 3 (PG-PT) and Pb 5 Ge 3 O 11 -Pb(Zr 1/2 Ti 1/2 )O 3 (PG-PZT) systems. In these systems the PG crystallized into a ferroelectric phase, producing a multiple ferroelectric phase composite at low temperatures, PG-PT or PG-PZT. In this way the non-ferroelectric component of traditional ferroelectric glass-ceramics was eliminated

  9. Characteristics of the process K+p→K+anti ppp at 12 GeV/c

    International Nuclear Information System (INIS)

    Armstrong, T.A.; Frame, D.; Hughes, I.S.; Kumar, B.R.; Lewis, G.M.; Macallister, J.B.; Stewart, D.T.; Turnbull, R.M.

    1979-01-01

    Data are presented on the reaction K + p→K + anti ppp at 12 GeV/c from an experiment using the OMEGA spectrometer at CERN. A clear Λ(1520) signal is observed in the process K + p→anti Λ(1520)pp and angular distributions and correlations are presented for this process. The angular distributions for the reaction in which anti Λ(1520) is not produced show an appreciable backward K + peak. (Auth.)

  10. Materials and devices for quantum information processing in Si/SiGe

    Energy Technology Data Exchange (ETDEWEB)

    Sailer, Juergen

    2010-12-15

    In this thesis, we cover and discuss the complete way from material science, the fabrication of two-dimensional electron systems (2DES) in Si/SiGe heterostructures in molecular beam epitaxy (MBE), to quantum effects in few-electron devices based on these samples. We applied and compared two different approaches for the creation of pseudo-substrates that are as smooth, relaxed and defect free as possible. In the 'graded buffer' concept, starting from pure Si, the Ge content of the SiGe alloy is slowly and linearly increased until the desired Ge content is reached. In contrast, in the so-called 'low-temperature Si' concept, the SiGe alloy is deposited directly with the final Ge content, but onto a layer of highly defective Si. In terms of crystal defects, the 'graded buffer' turned out to be superior in comparison to the 'low-temperature Si' concept at the expense of a significantly higher material consumption. By continued optimization of the growth process, aiming at reducing the influence of the impurity, it nevertheless became possible to improve the charge carrier mobility from a mere 2000 cm{sup 2}/(Vs) to a record mobility exceeding 100 000 cm{sup 2}/(Vs). Within this work, we extended our MBE system with an electron beam evaporator for nuclear spin free {sup 28}Si. Together with the already existing effusion cell for {sup 70}Ge we were able to realize first 2DES in a nuclear spin free environment after successfully putting it to operation. The highest mobility 2DES in a nuclear spin free environment which have been realized in this thesis exhibited electron mobilities of up to 55 000 cm{sup 2}/(Vs). Quantum effects in Si/SiGe have been investigated in two- and zero-dimensional nanostructures. A remarkable phenomenon in the regime of the integer quantum Hall effect in Si/SiGe 2DES has been discovered and researched. For applications in quantum information processing and for the creation of qubits it is mandatory to

  11. 270GHz SiGe BiCMOS manufacturing process platform for mmWave applications

    Science.gov (United States)

    Kar-Roy, Arjun; Preisler, Edward J.; Talor, George; Yan, Zhixin; Booth, Roger; Zheng, Jie; Chaudhry, Samir; Howard, David; Racanelli, Marco

    2011-11-01

    TowerJazz has been offering the high volume commercial SiGe BiCMOS process technology platform, SBC18, for more than a decade. In this paper, we describe the TowerJazz SBC18H3 SiGe BiCMOS process which integrates a production ready 240GHz FT / 270 GHz FMAX SiGe HBT on a 1.8V/3.3V dual gate oxide CMOS process in the SBC18 technology platform. The high-speed NPNs in SBC18H3 process have demonstrated NFMIN of ~2dB at 40GHz, a BVceo of 1.6V and a dc current gain of 1200. This state-of-the-art process also comes with P-I-N diodes with high isolation and low insertion losses, Schottky diodes capable of exceeding cut-off frequencies of 1THz, high density stacked MIM capacitors, MOS and high performance junction varactors characterized up to 50GHz, thick upper metal layers for inductors, and various resistors such as low value and high value unsilicided poly resistors, metal and nwell resistors. Applications of the SBC18H3 platform for millimeter-wave products for automotive radars, phased array radars and Wband imaging are presented.

  12. The microstructural changes of Ge2Sb2Te5 thin film during crystallization process

    Science.gov (United States)

    Xu, Jingbo; Qi, Chao; Chen, Limin; Zheng, Long; Xie, Qiyun

    2018-05-01

    Phase change memory is known as the most promising candidate for the next generation nonvolatile memory technology. In this paper, the microstructural changes of Ge2Sb2Te5 film, which is the most common choice of phase change memory material, has been carefully studied by the combination of several characterization techniques. The combination of resistance measurements, X-ray diffraction, Raman spectroscopy and X-ray reflectivity allows us to simultaneously extract the characteristics of microstructural changes during crystallization process. The existence of surface/interface Ge2Sb2Te5 layer has been proposed here based on X-ray reflectivity measurements. Although the total film thickness decreases, as a result of the phase transition from amorphous to metastable crystalline cubic and then to the stable hexagonal phase, the surface/interface thickness increases after crystallization. Moreover, the increase of average grain size, density and surface roughness has been confirmed during thermal annealing process.

  13. Investigation into the production of metastable Nb3Ge powder via the rotating electrode process

    International Nuclear Information System (INIS)

    McCormick, J.P.

    1977-12-01

    The production of metastable Nb 3 Ge powder via the rotating electrode process (REP) employing ''splat cooling'' was investigated. An electrode capable of withstanding the thermal shock of the electric arc used in REP was produced through powder metallurgy techniques. The effect of various parameters involved in the rotating electrode process was studied in correlation with process control and crystal structure, microstructure and compositional analyses of the powder produced. Superconducting transition temperature measurements were made on the powder both as-produced and after annealing experiments

  14. Effect of Preparation Method on Phase Formation Process and Structural and Magnetic Properties of Mn2.5Ge Samples

    Directory of Open Access Journals (Sweden)

    R. Sobhani

    2016-12-01

    Full Text Available In this paper, the phase formation process of Mn2.5Ge samples, prepared by mechanical alloying of Mn and Ge metal powders and annealing, has been studied. Results showed that in the milled samples the stable phase is Mn11Ge8 compound with orthorhombic structure and Pnam space group. The value of saturation magnetization increases by increasing milling time from 0.2 up to 1.95 (Am2Kg-1. The remanece of the samples increases by increasing the milling time while the coercivity decreases. Annealing of 15-hour milled sample results in disappearance of Mn and Ge and the formation of new phases of Mn3Ge, Mn5Ge2, Mn5Ge3 and Mn2.3Ge. Mn3Ge is the main phase with Do22 tetragonal structure and I4/mmm space group which is stable and dominant. The enhancement of saturation magnetization in the annealed sample is related to the formation of three new magnetic phases and the increase of coercivity is due to the presence of Mn3Ge compound with tetragonal structure. Studies were replicated on samples made by arc melting method to compare the results and to investigate the effect of the preparation method on phase formation and structural and magnetic properties of the materials. In these samples the saturation value was in range of 0.2 up to 1.95 (Am2Kg-1 depending on preparation methods. Rietveld refinement shows that Mn2.3Ge sample prepared from arc melted under 620oC anealing is single phase. Magnetic analysis of this sample show a saturation magnetization of 5.252(Am2Kg-1 and 0.005 T coercive field.

  15. Evolution of processing of GE fuel clad tubing for corrosion resistance in boiling water reactors

    Energy Technology Data Exchange (ETDEWEB)

    Williams, C.D. [GE Nuclear Energy, Wilmington, NC (United States); Adamson, R.B. [GE Nuclear Energy, Wilmington, NC (United States); Marlowe, M.O. [GE Nuclear Energy, Wilmington, NC (United States); Plaza-Meyer, E. [GE Nuclear Energy, Wilmington, NC (United States); Proebstle, R.A. [GE Nuclear Energy, Wilmington, NC (United States); White, D.W. [GE Nuclear Energy, Wilmington, NC (United States)

    1996-05-01

    The current modification of the primary GE in-process solution-quench heat treatment, an (alpha+beta) solution-quench carried out at a tube diameter requiring only two subsequent reduction and anneal cycles, is applicable to Zr barrier fuel clad tubing, to non-barrier fuel clad tubing, and to the TRICLAD tubing product. A combination of good in-reactor corrosion performance and degradation resistance is anticipated for these products, based on knowledge of metallurgical characteristics and supported by the demonstrated performance capability of the Zircaloy-2 materials used. (orig.)

  16. Implementation of RLS-based Adaptive Filterson nVIDIA GeForce Graphics Processing Unit

    OpenAIRE

    Hirano, Akihiro; Nakayama, Kenji

    2011-01-01

    This paper presents efficient implementa- tion of RLS-based adaptive filters with a large number of taps on nVIDIA GeForce graphics processing unit (GPU) and CUDA software development environment. Modification of the order and the combination of calcu- lations reduces the number of accesses to slow off-chip memory. Assigning tasks into multiple threads also takes memory access order into account. For a 4096-tap case, a GPU program is almost three times faster than a CPU program.

  17. Formation and relaxation processes of photoinduced defects in a Ge-doped SiO2 glass

    International Nuclear Information System (INIS)

    Yamaguchi, M.; Saito, K.; Ikushima, A.J.

    2002-01-01

    The defect centers induced by ArF laser irradiation in Ge-doped SiO 2 have been investigated by the electron-spin resonance method. In order to observe formation and relaxation processes of the defects, step annealing has been carried out after the irradiation at 77 K. The thermally induced decay of the self-trapped hole (STH) and formation of the so-called Ge(2) centers have been observed with increasing temperature. The result suggests that the holes are transferred from the STH to the Ge(2)

  18. Study of Various Processes with 160 A GeV Pb Beam

    CERN Multimedia

    2002-01-01

    % WA101 \\\\ \\\\ Ten modules of BP-1 glass detectors interleaved with various targets ranging from C to Pb were exposed to the 160~A~GeV~Pb beam in the November-December run of 1994 at CERN SPS. The experiment was carried out at normal incidence at a beam density of $\\sim$~600~cm$ ^- ^{2} $. The dimension of each plate of BP-1 glass was 50~mm~x~50~mm~x~1~mm. We etched the glass in 70\\% CH$ _{3} $SO$ _{3} $H at 50 $^{0}$C or in 48\\%~HF at room temperature. The charge threshold is found to be Z$ _{t} _{h} $ $\\sim$ 68 and 70 respectively. Using the automated scanning and measurement system developed at Berkeley, we have demonstrated that the charge resolution for Pb ions is $\\sigma _{Z} $~=~0.14 charge unit from a single measurement within a distance of 30~$\\mu$m. This excellent charge resolution allows us to make the proposed measurements of cross-sections for various processes. \\\\ \\\\We use this detector system to measure cross-sections for various processes in heavy ion collisions of 160~A~GeV~Pb with different t...

  19. Electron pulsed beam induced processing of thin film surface by Nb3Ge deposited into a stainless steel tape

    International Nuclear Information System (INIS)

    Vavra, I.; Korenev, S.A.

    1988-01-01

    A surface of superconductive thin film of Nb 3 Ge deposited onto a stainless steel tape was processed using the electron beam technique. The electron beam used had the following parameters: beam current density from 400 to 1000 A/cm 2 ; beam energy 100 keV; beam impulse length 300 ns. By theoretical analysis it is shown that the heating of film surface is an adiabatic process. It corresponds to our experimental data and pictures showing a surface remelting due to electron beam influence. After beam processing the superconductive parameters of the film remain unchanged. Roentgenograms have been analysed of Nb 3 Ge film surface recrystallized due to electron beam influence

  20. WSi2 in Si(1-x)Ge(x) Composites: Processing and Thermoelectric Properties

    Science.gov (United States)

    Mackey, Jonathan A.; Sehirlioglu, Alp; Dynys, Fred

    2015-01-01

    Traditional SiGe thermoelectrics have potential for enhanced figure of merit (ZT) via nano-structuring with a silicide phase, such as WSi2. A second phase of nano-sized silicides can theoretically reduce the lattice component of thermal conductivity without significantly reducing the electrical conductivity. However, experimentally achieving such improvements in line with the theory is complicated by factors such as control of silicide size during sintering, dopant segregation, matrix homogeneity, and sintering kinetics. Samples were prepared using powder metallurgy techniques; including mechano-chemical alloying, via ball milling, and spark plasma sintering for densification. Processing, micro-structural development, and thermoelectric properties will be discussed. Additionally, couple and device level characterization will be introduced.

  1. Preliminary report on an intercomparison of methods for processing Ge(Li) gamma-ray spectra

    International Nuclear Information System (INIS)

    Parr, R.M.; Houtermans, H.; Schaerf, K.

    1978-01-01

    An intercomparison has been organized by the IAEA for the purpose of evaluating methods for processing Ge(Li) gamma-ray spectra. These spectra cover an energy range of about 1MeV and, with one exception, contain only well separated single peaks; another spectrum contains double peaks with various relative intensities and degrees of overlap. The spectra were prepared in such a way that the areas and positions of all peaks, relative to a standard spectrum which is also provided, are known exactly. The intercomparison enables the user to test the ability of his methods (1) to detect small peaks near the limit of detectability; (2) to determine the position and area of more easily detectable peaks, and (3) to determine the position and area of overlapping double peaks. The method of preparation of the spectra and the organization of the intercomparison are described in this report. (author)

  2. Processing and characterization of new oxy-sulfo-telluride glasses in the Ge-Sb-Te-S-O system

    International Nuclear Information System (INIS)

    Smith, C.; Jackson, J.; Petit, L.; Rivero-Baleine, C.; Richardson, K.

    2010-01-01

    New oxy-sulfo-telluride glasses have been prepared in the Ge-Sb-Te-S-O system employing a two-step melting process which involves the processing of a chalcogenide glass (ChG) and subsequent melting with TeO 2 or Sb 2 O 3 . The progressive incorporation of O at the expense of S was found to increase the density and the glass transition temperature and to decrease the molar volume of the investigated oxy-sulfo-telluride glasses. We also observed a shift of the vis-NIR cut-off wavelength to longer wavelength probably due to changes in Sb coordination within the glass matrix and overall matrix polarizability. Using Raman spectroscopy, correlations have been shown between the formation of Ge- and Sb-based oxysulfide structural units and the S/O ratio. Lastly, two glasses with similar composition (Ge 20 Sb 6 S 64 Te 3 O 7 ) processed by melting the Ge 23 Sb 7 S 70 glass with TeO 2 or the Ge 23 Sb 2 S 72 Te 4 glass with Sb 2 O 3 were found to have slightly different physical, thermal, optical and structural properties. These changes are thought to result mainly from the higher moisture content and sensitivity of the TeO 2 starting materials as compared to that of the Sb 2 O 3 . - Graphical abstract: In this paper, we discuss our most recent findings on the processing and characterization of new ChG glasses prepared with small levels of Te, melted either with TeO 2 or Sb 2 O 3 powders. We explain how these new oxy-sulfo-telluride glasses are prepared and we correlate the physical, thermal and optical properties of the investigated glasses to the structure changes induced by the addition of oxygen in the Ge-Sb-S-Te glass network.

  3. Production, radiochemical processing and quality evaluation of 68Ge. Chapter 2

    International Nuclear Information System (INIS)

    Roesch, F.; Filosofov, D.V.

    2010-01-01

    In this chapter, the optimum chemical forms of the target material for the most relevant 68 Ge production routes are discussed. The principal methods for separation of 68 Ge (ion exchange, extraction, volatilization, precipitation, etc.) allowing high chemical separation yields of the parent radionuclide are also discussed

  4. A Polymorphism in the Processing Body Component Ge-1 Controls Resistance to a Naturally Occurring Rhabdovirus in Drosophila.

    Directory of Open Access Journals (Sweden)

    Chuan Cao

    2016-01-01

    Full Text Available Hosts encounter an ever-changing array of pathogens, so there is continual selection for novel ways to resist infection. A powerful way to understand how hosts evolve resistance is to identify the genes that cause variation in susceptibility to infection. Using high-resolution genetic mapping we have identified a naturally occurring polymorphism in a gene called Ge-1 that makes Drosophila melanogaster highly resistant to its natural pathogen Drosophila melanogaster sigma virus (DMelSV. By modifying the sequence of the gene in transgenic flies, we identified a 26 amino acid deletion in the serine-rich linker region of Ge-1 that is causing the resistance. Knocking down the expression of the susceptible allele leads to a decrease in viral titre in infected flies, indicating that Ge-1 is an existing restriction factor whose antiviral effects have been increased by the deletion. Ge-1 plays a central role in RNA degradation and the formation of processing bodies (P bodies. A key effector in antiviral immunity, the RNAi induced silencing complex (RISC, localises to P bodies, but we found that Ge-1-based resistance is not dependent on the small interfering RNA (siRNA pathway. However, we found that Decapping protein 1 (DCP1 protects flies against sigma virus. This protein interacts with Ge-1 and commits mRNA for degradation by removing the 5' cap, suggesting that resistance may rely on this RNA degradation pathway. The serine-rich linker domain of Ge-1 has experienced strong selection during the evolution of Drosophila, suggesting that this gene may be under long-term selection by viruses. These findings demonstrate that studying naturally occurring polymorphisms that increase resistance to infections enables us to identify novel forms of antiviral defence, and support a pattern of major effect polymorphisms controlling resistance to viruses in Drosophila.

  5. Ge/IIIV fin field-effect transistor common gate process and numerical simulations

    Science.gov (United States)

    Chen, Bo-Yuan; Chen, Jiann-Lin; Chu, Chun-Lin; Luo, Guang-Li; Lee, Shyong; Chang, Edward Yi

    2017-04-01

    This study investigates the manufacturing process of thermal atomic layer deposition (ALD) and analyzes its thermal and physical mechanisms. Moreover, experimental observations and computational fluid dynamics (CFD) are both used to investigate the formation and deposition rate of a film for precisely controlling the thickness and structure of the deposited material. First, the design of the TALD system model is analyzed, and then CFD is used to simulate the optimal parameters, such as gas flow and the thermal, pressure, and concentration fields, in the manufacturing process to assist the fabrication of oxide-semiconductors and devices based on them, and to improve their characteristics. In addition, the experiment applies ALD to grow films on Ge and GaAs substrates with three-dimensional (3-D) transistors having high electric performance. The electrical analysis of dielectric properties, leakage current density, and trapped charges for the transistors is conducted by high- and low-frequency measurement instruments to determine the optimal conditions for 3-D device fabrication. It is anticipated that the competitive strength of such devices in the semiconductor industry will be enhanced by the reduction of cost and improvement of device performance through these optimizations.

  6. Disentangling nonradiative recombination processes in Ge micro-crystals on Si substrates

    International Nuclear Information System (INIS)

    Pezzoli, Fabio; Giorgioni, Anna; Gatti, Eleonora; Grilli, Emanuele; Bonera, Emiliano; Miglio, Leo; Gallacher, Kevin; Millar, Ross W.; Paul, Douglas J.; Isa, Fabio; Biagioni, Paolo; Isella, Giovanni

    2016-01-01

    We address nonradiative recombination pathways by leveraging surface passivation and dislocation management in μm-scale arrays of Ge crystals grown on deeply patterned Si substrates. The time decay photoluminescence (PL) at cryogenic temperatures discloses carrier lifetimes approaching 45 ns in band-gap engineered Ge micro-crystals. This investigation provides compelling information about the competitive interplay between the radiative band-edge transitions and the trapping of carriers by dislocations and free surfaces. Furthermore, an in-depth analysis of the temperature dependence of the PL, combined with capacitance data and finite difference time domain modeling, demonstrates the effectiveness of GeO_2 in passivating the surface of Ge and thus in enhancing the room temperature PL emission.

  7. Disentangling nonradiative recombination processes in Ge micro-crystals on Si substrates

    Science.gov (United States)

    Pezzoli, Fabio; Giorgioni, Anna; Gallacher, Kevin; Isa, Fabio; Biagioni, Paolo; Millar, Ross W.; Gatti, Eleonora; Grilli, Emanuele; Bonera, Emiliano; Isella, Giovanni; Paul, Douglas J.; Miglio, Leo

    2016-06-01

    We address nonradiative recombination pathways by leveraging surface passivation and dislocation management in μm-scale arrays of Ge crystals grown on deeply patterned Si substrates. The time decay photoluminescence (PL) at cryogenic temperatures discloses carrier lifetimes approaching 45 ns in band-gap engineered Ge micro-crystals. This investigation provides compelling information about the competitive interplay between the radiative band-edge transitions and the trapping of carriers by dislocations and free surfaces. Furthermore, an in-depth analysis of the temperature dependence of the PL, combined with capacitance data and finite difference time domain modeling, demonstrates the effectiveness of GeO2 in passivating the surface of Ge and thus in enhancing the room temperature PL emission.

  8. Disentangling nonradiative recombination processes in Ge micro-crystals on Si substrates

    Energy Technology Data Exchange (ETDEWEB)

    Pezzoli, Fabio, E-mail: fabio.pezzoli@unimib.it; Giorgioni, Anna; Gatti, Eleonora; Grilli, Emanuele; Bonera, Emiliano; Miglio, Leo [LNESS and Dipartimento di Scienza dei Materiali, Università degli Studi di Milano-Bicocca, via Cozzi 55, I-20125 Milano (Italy); Gallacher, Kevin; Millar, Ross W.; Paul, Douglas J. [School of Engineering, University of Glasgow, Rankine Building, Oakfield Avenue, Glasgow G12 8LT (United Kingdom); Isa, Fabio [LNESS, Dipartimento di Fisica del Politecnico di Milano and IFN-CNR, Polo Territoriale di Como, Via Anzani 42, I-22100 Como (Italy); Laboratory for Solid State Physics, ETH Zurich, Otto-Stern-Weg 1, CH-8093 Zürich (Switzerland); Biagioni, Paolo [LNESS, Dipartimento di Fisica del Politecnico di Milano and IFN-CNR, Piazza Leonardo da Vinci 32, I-20133 Milano (Italy); Isella, Giovanni [LNESS, Dipartimento di Fisica del Politecnico di Milano and IFN-CNR, Polo Territoriale di Como, Via Anzani 42, I-22100 Como (Italy)

    2016-06-27

    We address nonradiative recombination pathways by leveraging surface passivation and dislocation management in μm-scale arrays of Ge crystals grown on deeply patterned Si substrates. The time decay photoluminescence (PL) at cryogenic temperatures discloses carrier lifetimes approaching 45 ns in band-gap engineered Ge micro-crystals. This investigation provides compelling information about the competitive interplay between the radiative band-edge transitions and the trapping of carriers by dislocations and free surfaces. Furthermore, an in-depth analysis of the temperature dependence of the PL, combined with capacitance data and finite difference time domain modeling, demonstrates the effectiveness of GeO{sub 2} in passivating the surface of Ge and thus in enhancing the room temperature PL emission.

  9. Ex situ n+ doping of GeSn alloys via non-equilibrium processing

    Science.gov (United States)

    Prucnal, S.; Berencén, Y.; Wang, M.; Rebohle, L.; Böttger, R.; Fischer, I. A.; Augel, L.; Oehme, M.; Schulze, J.; Voelskow, M.; Helm, M.; Skorupa, W.; Zhou, S.

    2018-06-01

    Full integration of Ge-based alloys like GeSn with complementary-metal-oxide-semiconductor technology would require the fabrication of p- and n-type doped regions for both planar and tri-dimensional device architectures which is challenging using in situ doping techniques. In this work, we report on the influence of ex situ doping on the structural, electrical and optical properties of GeSn alloys. n-type doping is realized by P implantation into GeSn alloy layers grown by molecular beam epitaxy (MBE) followed by flash lamp annealing. We show that effective carrier concentration of up to 1 × 1019 cm‑3 can be achieved without affecting the Sn distribution. Sn segregation at the surface accompanied with an Sn diffusion towards the crystalline/amorphous GeSn interface is found at P fluences higher than 3 × 1015 cm‑2 and electron concentration of about 4 × 1019 cm‑3. The optical and structural properties of ion-implanted GeSn layers are comparable with the in situ doped MBE grown layers.

  10. Processing high-Tc superconductors with GeV heavy ions

    International Nuclear Information System (INIS)

    Marwick, A.D.; Civale, L.; Krusin-Elbaum, L.; Worthington, T.K.; Holtzberg, F.; Thompson, J.R.; Sun, Y.R.; Kerchner, H.R.

    1992-01-01

    Irradiation of high-T c superconducting crystals with low doses (10 10 --10 11 ions/cm 2 ) of GeV heavy ions (0.58 GeV Sn-116; 1.0-GeV Au-197) produces a unique microstructure consisting of discrete amorphous columns which are only a few nm in diameter but tens of microns long. It has been found recently that this columnar microstructure causes larger increases in magnetization and critical current at high temperature and high magnetic field than other types of defects in these materials. This can be understood as a consequence of the effective pinning of magnetic vortex lines provided by the columnar defects. Measurements confirm that the pinning is strongest when the magnetic field is aligned with the ion tracks. Differences in the pinning in different materials can be related to differences in their anisotropy, which affects the structure of the vortices and their pinning at columnar defects

  11. Effect of a Stepped Si(100) Surface on the Nucleation Process of Ge Islands

    Science.gov (United States)

    Yesin, M. Yu.; Nikiforov, A. I.; Timofeev, V. A.; Mashanov, V. I.; Tuktamyshev, A. R.; Loshkarev, I. D.; Pchelyakov, O. P.

    2018-03-01

    Nucleation of Ge islands on a stepped Si(100) surface is studied. It is shown by diffraction of fast electrons that at a temperature of 600°C, constant flux of Si, and deposition rate of 0.652 Å/s, a series of the 1×2 superstructure reflections completely disappears, if the Si (100) substrate deviated by an angle of 0.35° to the (111) face is preliminarily heated to 1000°C. The disappearance of the 1×2 superstructure reflexes is due to the transition from the surface with monoatomic steps to that with diatomic ones. Investigations of the Ge islands' growth were carried out on the Si(100) surface preliminarily annealed at temperatures of 800 and 1000°C. It is shown that the islands tend to nucleate at the step edges.

  12. GeVaDSs – decision support system for novel Genetic Vaccine development process

    Directory of Open Access Journals (Sweden)

    Blazewicz Jacek

    2012-05-01

    Full Text Available Abstract Background The lack of a uniform way for qualitative and quantitative evaluation of vaccine candidates under development led us to set up a standardized scheme for vaccine efficacy and safety evaluation. We developed and implemented molecular and immunology methods, and designed support tools for immunization data storage and analyses. Such collection can create a unique opportunity for immunologists to analyse data delivered from their laboratories. Results We designed and implemented GeVaDSs (Genetic Vaccine Decision Support system an interactive system for efficient storage, integration, retrieval and representation of data. Moreover, GeVaDSs allows for relevant association and interpretation of data, and thus for knowledge-based generation of testable hypotheses of vaccine responses. Conclusions GeVaDSs has been tested by several laboratories in Europe, and proved its usefulness in vaccine analysis. Case study of its application is presented in the additional files. The system is available at: http://gevads.cs.put.poznan.pl/preview/(login: viewer, password: password.

  13. In situ X-ray diffraction study of crystallization process of GeSbTe thin films during heat treatment

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Naohiko [Toyota Central R and D Labs., Inc., Nagakute, Aichi 480-1192 (Japan)]. E-mail: e0957@mosk.tytlabs.co.jp; Konomi, Ichiro [Toyota Central R and D Labs., Inc., Nagakute, Aichi 480-1192 (Japan); Seno, Yoshiki [Toyota Central R and D Labs., Inc., Nagakute, Aichi 480-1192 (Japan); Motohiro, Tomoyoshi [Toyota Central R and D Labs., Inc., Nagakute, Aichi 480-1192 (Japan)

    2005-05-15

    The crystallization processes of the Ge{sub 2}Sb{sub 2}Te{sub 5} thin film used for PD and DVD-RAM were studied in its realistic optical disk film configurations for the first time by X-ray diffraction using an intense X-ray beam of a synchrotron orbital radiation facility (SPring-8) and in situ quick detection with a Position-Sensitive-Proportional-Counter. The dependence of the amorphous-to-fcc phase-change temperature T{sub 1} on the rate of temperature elevation R{sub et} gave an activation energy E{sub a}: 0.93 eV much less than previously reported 2.2 eV obtained from a model sample 25-45 times thicker than in the real optical disks. The similar measurement on the Ge{sub 4}Sb{sub 1}Te{sub 5} film whose large reflectance change attains the readability by CD-ROM drives gave E{sub a}: 1.13 eV with larger T{sub 1} than Ge{sub 2}Sb{sub 2}Te{sub 5} thin films at any R{sub et} implying a lower sensitivity in erasing as well as a better data stability of the phase-change disk.

  14. In situ X-ray diffraction study of crystallization process of GeSbTe thin films during heat treatment

    International Nuclear Information System (INIS)

    Kato, Naohiko; Konomi, Ichiro; Seno, Yoshiki; Motohiro, Tomoyoshi

    2005-01-01

    The crystallization processes of the Ge 2 Sb 2 Te 5 thin film used for PD and DVD-RAM were studied in its realistic optical disk film configurations for the first time by X-ray diffraction using an intense X-ray beam of a synchrotron orbital radiation facility (SPring-8) and in situ quick detection with a Position-Sensitive-Proportional-Counter. The dependence of the amorphous-to-fcc phase-change temperature T 1 on the rate of temperature elevation R et gave an activation energy E a : 0.93 eV much less than previously reported 2.2 eV obtained from a model sample 25-45 times thicker than in the real optical disks. The similar measurement on the Ge 4 Sb 1 Te 5 film whose large reflectance change attains the readability by CD-ROM drives gave E a : 1.13 eV with larger T 1 than Ge 2 Sb 2 Te 5 thin films at any R et implying a lower sensitivity in erasing as well as a better data stability of the phase-change disk

  15. Efficiency-limiting processes in OPV bulk heterojunctions of GeNIDTBT and IDT-based acceptors

    KAUST Repository

    Al-Saggaf, Sarah M.

    2018-05-16

    The successful realization of highly efficient bulk heterojunction OPV devices requires the development of organic donor and acceptor materials with tailored properties. Recently, non-fullerene acceptors (NFAs) have emerged as an alternative to the ubiquitously used fullerene derivatives. NFAs showed a rapid increase in efficiencies, now exceeding a PCE of 13%. In my thesis research, I used two small molecule IDT-based acceptors, namely O-IDTBR and O-IDTBCN, in combination with a wide bandgap donor polymer, GeNIDT-BT, as active material in BHJ solar cells and investigated their photophysical characteristics. The polymer combined with O-IDTBR as acceptor achieved a power conversion efficiency of only 2%, which is significantly lower than that obtained for the system of GeNIDT-BT: O-IDTBCN (5.3%). Using nano- to microsecond transient absorption spectroscopy, I investigated both systems and demonstrated that GeNIDT-BT:O-IDTBR exhibits more geminate recombination of interfacial charge-transfer states, leading to lower short circuit currents. Using time-delayed collection field experiments, I studied the field dependence of charge generation and its impact on the device fill factor. Overall, my results provide a qualitative understanding of the efficiency-limiting processes in both systems and their impact on device performance.

  16. Infrared absorption, multiphonon processes and time reversal effect on Si and Ge band structure

    International Nuclear Information System (INIS)

    Kunert, H.W.; Machatine, A.G.J.; Malherbe, J.B.; Barnas, J.; Hoffmann, A.; Wagner, M.R.

    2008-01-01

    We have examined the effect of Time Reversal Symmetry (TRS) on vibrational modes and on the electronic band structure of Si and Ge. Most of the primary non-interacting modes are not affected by TRS. Only phonons originating from high symmetry lines S and A of the Brillouin Zone (BZ) indicate extra degeneracy. Selection rules for some two and three phonons originating from high symmetry lines are determined. The states of electrons and holes described by electronic band structure due to spin-inclusion are assigned by spinor representations of the double space group. Inclusion of the TRS into the band structure results in extra degeneracy of electrons and holes, and therefore optical selection rules suppose to be modified

  17. Photochemical process of divalent germanium responsible for photorefractive index change in GeO2-SiO2 glasses.

    Science.gov (United States)

    Sakoh, Akifumi; Takahashi, Masahide; Yoko, Toshinobu; Nishii, Junji; Nishiyama, Hiroaki; Miyamoto, Isamu

    2003-10-20

    The photoluminescence spectra of the divalent Ge (Ge2+) center in GeO2-SiO2 glasses with different photosensitivities were investigated by means of excitation-emission energy mapping. The ultraviolet light induced photorefractivity has been correlated with the local structure around the Ge2+ centers. The glasses with a larger photorefractivity tended to exhibit a greater band broadening of the singlet-singlet transition on the higher excitation energy side accompanied by an increase in the Stokes shifts. This strongly suggests the existence of highly photosensitive Ge2+ centers with higher excitation energies. It is also found that the introduction of a hydroxyl group or boron species in GeO2-SiO2 glasses under appropriate conditions modifies the local environment of Ge2+ leading to an enhanced photorefractivity.

  18. Multiparticle Production Process in $pp$ Interaction with High Multiplicity at E_p=70 GeV. Proposal "Termalization"

    CERN Document Server

    Avdeichikov, V V; Balandin, V P; Vasendina, V A; Zhidkov, N K; Zolin, L S; Zulkarneev, R Ya; Kireev, V I; Kosarev, I G; Kuzmin, N A; Kuraev, E A; Mandjavidze, I D; Nikitin, V A; Petukhov, Yu P; Peshekhonov, V D; Rufanov, I A; Susakian, A N; Yukaev, A I; Basiladze, Sergei G; Volkov, V Yu; Ermolov, P F; Kramarenko, V A; Kubarovskii, A V; Leflat, A K; Merkin, M M; Popov, V V; Tikhonova, L A; Anikeev, A N; Vasilchenko, V G; Vorobev, A P; Lapshin, V G; Maiorov, S V; Melnik, Yu M; Meshchanin, A P; Ryadovikov, V N; Kholodenko, A G; Tsyupa, Yu P; Chikilev, O G; Yakutin, A E; Dremin, I M; Kokoulina, E S; Pankov, A A; Kuvshinov, V I

    2004-01-01

    The goal of the proposed experiment is the investigation of the collective behaviour of particles in the process of multiple hadron production in the $pp$ interaction $pp\\to n_\\pi\\pi+2N$ at the beam energy $E_{\\rm lab}=70$ GeV. The domain of high multiplicity $n_\\pi=20{-}35$ or $z=n/\\bar n=3{-}5$ will be studied. Near the threshold of the reaction $n_\\pi\\to 69$, all particles get a small relative momentum. As a consequence of the multiboson interference a number of collective effects may occur. In particular, drastic increase of the partial cross section $\\sigma(n)$ of the $n$ identical particles production, as compared with commonly accepted extrapolation, and increase of the rate of direct photons are expected. The experiment is carried out on the modernized installation SVD, a spectrometer with a vertex detector which is supplied with a trigger system for registration of rare events with high multiplicity, on extracted proton beam of the IHEP (Protvino) 70 GeV accelerator. Required beam intensity is $\\sim ...

  19. Non-equilibrium processes in p + Ag collisions at GeV energies

    Science.gov (United States)

    Fidelus, M.; Filges, D.; Goldenbaum, F.; Jarczyk, L.; Kamys, B.; Kistryn, M.; Kistryn, St.; Kozik, E.; Kulessa, P.; Machner, H.; Magiera, A.; Piskor-Ignatowicz, B.; Pysz, K.; Rudy, Z.; Sharma, Sushil K.; Siudak, R.; Wojciechowski, M.; PISA Collaboration

    2017-12-01

    The double differential spectra d2σ /d Ω d E of p , d , t , 3,4,6He, 6,7,8,9Li, 7,9,10Be, and 10,11,12B were measured at seven scattering angles, 15.6∘, 20∘, 35∘, 50∘, 65∘, 80∘, and 100∘, in the laboratory system for proton induced reactions on a silver target. Measurements were done for three proton energies: 1.2, 1.9, and 2.5 GeV. The experimental data were compared to calculations performed by means of two-step theoretical microscopic models. The first step of the reaction was described by the intranuclear cascade model incl4.6 and the second one by four different models (ABLA07, GEM2, gemini++, and SMM) using their standard parameter settings. Systematic deviations of the data from predictions of the models were observed. The deviations were especially large for the forward scattering angles and for the kinetic energy of emitted particles in the range from about 50 to 150 MeV. This suggests that some important non-equilibrium mechanism is lacking in the present day microscopic models of proton-nucleus collisions in the studied beam energy range.

  20. Improvement of the GERDA Ge Detectors Energy Resolution by an Optimized Digital Signal Processing

    Science.gov (United States)

    Benato, G.; D'Andrea, V.; Cattadori, C.; Riboldi, S.

    GERDA is a new generation experiment searching for neutrinoless double beta decay of 76Ge, operating at INFN Gran Sasso Laboratories (LNGS) since 2010. Coaxial and Broad Energy Germanium (BEGe) Detectors have been operated in liquid argon (LAr) in GERDA Phase I. In the framework of the second GERDA experimental phase, both the contacting technique, the connection to and the location of the front end readout devices are novel compared to those previously adopted, and several tests have been performed. In this work, starting from considerations on the energy scale stability of the GERDA Phase I calibrations and physics data sets, an optimized pulse filtering method has been developed and applied to the Phase II pilot tests data sets, and to few GERDA Phase I data sets. In this contribution the detector performances in term of energy resolution and time stability are here presented. The improvement of the energy resolution, compared to standard Gaussian shaping adopted for Phase I data analysis, is discussed and related to the optimized noise filtering capability. The result is an energy resolution better than 0.1% at 2.6 MeV for the BEGe detectors operated in the Phase II pilot tests and an improvement of the energy resolution in LAr of about 8% achieved on the GERDA Phase I calibration runs, compared to previous analysis algorithms.

  1. Investigation of inclusive processes π-A → π-X and πsup(-)A → Psub(backwards)X at 40 GeV/c

    International Nuclear Information System (INIS)

    Abrosimov, A.T.

    1984-01-01

    The study of the inclusive processe is peformed for nuclear targets: C, Al, Cu, Pb t 40 GeV/c. Inclusive spectra of negative pions are obtained in the region 0.1 - A → Psub(backward)X is studied in the 0.3-1 GeV/c region of secondary protons. Invariant cross sections of proton flying out in the back hemisphere are measured for the 120 deg - 175 deg angle interval. The A-dependece of the invariant cross section for this process is discussed

  2. Analyses of moments in pseudorapidity intervals at √s = 546 GeV by means of two probability distributions in pure-birth process

    International Nuclear Information System (INIS)

    Biyajima, M.; Shirane, K.; Suzuki, N.

    1988-01-01

    Moments in pseudorapidity intervals at the CERN Sp-barpS collider (√s = 546 GeV) are analyzed by means of two probability distributions in the pure-birth stochastic process. Our results show that a probability distribution obtained from the Poisson distribution as an initial condition is more useful than that obtained from the Kronecker δ function. Analyses of moments by Koba-Nielsen-Olesen scaling functions derived from solutions of the pure-birth stochastic process are also made. Moreover, analyses of preliminary data at √s = 200 and 900 GeV are added

  3. Design and Synthesis of novel CuxGeOy/Cu/C nanowires by in situ chemical reduction process with highly reversible capacity for Lithium Batteries

    International Nuclear Information System (INIS)

    Wang, Linlin; Zhang, Xiaozhu; Peng, Xia; Tang, Kaibin

    2015-01-01

    The synthesis and use of ternary metal oxides/metal particles/carbon hybrids, especially 1D naowires composed of MGeO 3 /M/C hybrids for energy storage, remains very few reports. In this work, 1D Cu x GeO y /Cu/C NWs (x < 1, y < 3) were successfully prepared by a simple method involving chemical reduction process and simultaneous carbon coating. It was found that through the polydopamine(PDA)-assisted chemical reduction process performed on the CuGeO 3 NWs, the phase partially transformed to a mixture of crystalline Cu (∼70 nm) and amorphous Cu x GeO y NWs with carbon coating, but the nanowire-shaped morphology was maintained. Electrochemical measurements showed that the Cu x GeO y /Cu/C NWs exhibited a stable reversible capacity of ∼900 mA h g −1 after 100 cycles. Even at 800 mA g −1 , it also exhibited excellent high rate capacity of 350 mA h g −1 . The newly generated Cu x GeO y @Cu@CNWs exhibit enhanced cycle stability with high lithium-storage capability compared to that of the as-preparedCuGeO 3 NWs. (*) The in situ-synthesized Cu nanoparticles, amorphous state and carbon coating might play an important role in activating and enhancing the reversibility of the conversion reaction of Cu x GeO y . In addition, this effective synthetic method might provide the methodology for the development of other ternary metal oxides/metal particles/carbon hybrids materials for energy storage.

  4. Oxygen transport and GeO2 stability during thermal oxidation of Ge

    Science.gov (United States)

    da Silva, S. R. M.; Rolim, G. K.; Soares, G. V.; Baumvol, I. J. R.; Krug, C.; Miotti, L.; Freire, F. L.; da Costa, M. E. H. M.; Radtke, C.

    2012-05-01

    Oxygen transport during thermal oxidation of Ge and desorption of the formed Ge oxide are investigated. Higher oxidation temperatures and lower oxygen pressures promote GeO desorption. An appreciable fraction of oxidized Ge desorbs during the growth of a GeO2 layer. The interplay between oxygen desorption and incorporation results in the exchange of O originally present in GeO2 by O from the gas phase throughout the oxide layer. This process is mediated by O vacancies generated at the GeO2/Ge interface. The formation of a substoichiometric oxide is shown to have direct relation with the GeO desorption.

  5. $\\beta$- decay of the N=Z, rp-process waiting points: $^{64}$Ge, $^{68}$Se and the N=Z+2: $^{66}$Ge, $^{70}$Se for accurate stellar weak-decay rates

    CERN Multimedia

    The contribution of electron capture to weak-decay rates has been neglected in model calculations of Type I X-ray bursts so far. Nucleosynthesis in these astrophysical events eventually proceeds through the rp-process near the proton drip-line. In particular, several N=Z nuclei such as $^{64}$Ge and $^{68}$Se act as waiting points in the nuclear flow due to the low S${_P}$ values of their Z+1 neighbours. Recent theoretical calculations have shown that, in these high density ($\\thicksim10^{6}$ g/cm$^3$) and high temperature (1 - 2 GK) scenarios, continuum electron capture rates might play an important role, in particular for species at and around these waiting point nuclei. This proposal is aimed at the study of the $\\beta^{+}$/EC-decay of the waiting point nuclei $^{64}$Ge, $^{68}$Se and their N=Z+2 second neighbours $^{66}$Ge and $^{70}$Se with the Total Absorption Spectroscopy method. This will allow for a detailed analysis of their contribution to the EC-decay rates in X-Ray burst explosions. The proposed ...

  6. Electric field distribution and the charge collection process in not-ideally compensated coaxial Ge(Li) detectors

    International Nuclear Information System (INIS)

    Szymczyk, W.M.; Moszynski, M.

    1978-01-01

    The not-ideally compensated space charge of donors and acceptors in lithium-drifted coaxial Ge(Li) detectors can modify the electric field distribution in the detector depleted volume, and influence in this way the charge collection process. Observations of the capacity, the time of charge collection (transit time), and the relative efficiency characteristics vs. detector bias voltage, showed that in conventional pin + coaaxial structures an undercompensation near the inner p-type core was typical. It was found that such an undercompensation had negligible consequences from the charge collection point of view. However, one case was observed where the modification near the outer electrode was present. In that case the charge pulses with remarkably increased rise-times were observed, as compared to the predictions based on the assumption of the classical, E proportional to 1/r, electric field distribution. The pulses expected from not-ideally compensated detectors were calculated using the Variable Velocity Approximation. The pulses expected from and much better agreement with the observed pulses was obtained. The calculated and observed dependencies of the charge transit times vs. reciprocal of the detector bias voltage exhibited, in the absence of the outer-electrode modification, linear parts. Measurement of their slopes permitted to find experimentally the depletion layer width provided the charge carriers mobility value was known, or vice versa. (Auth.)

  7. Intrinsic defect processes and elastic properties of Ti3AC2 (A = Al, Si, Ga, Ge, In, Sn) MAX phases

    Science.gov (United States)

    Christopoulos, S.-R. G.; Filippatos, P. P.; Hadi, M. A.; Kelaidis, N.; Fitzpatrick, M. E.; Chroneos, A.

    2018-01-01

    Mn+1AXn phases (M = early transition metal; A = group 13-16 element and X = C or N) have a combination of advantageous metallic and ceramic properties, and are being considered for structural applications particularly where high thermal conductivity and operating temperature are the primary drivers: for example in nuclear fuel cladding. Here, we employ density functional theory calculations to investigate the intrinsic defect processes and mechanical behaviour of a range of Ti3AC2 phases (A = Al, Si, Ga, Ge, In, Sn). Based on the intrinsic defect reaction, it is calculated that Ti3SnC2 is the more radiation-tolerant 312 MAX phase considered herein. In this material, the C Frenkel reaction is the lowest energy intrinsic defect mechanism with 5.50 eV. When considering the elastic properties of the aforementioned MAX phases, Ti3SiC2 is the hardest and Ti3SnC2 is the softest. All the MAX phases considered here are non-central force solids and brittle in nature. Ti3SiC2 is elastically more anisotropic and Ti3AlC2 is nearly isotropic.

  8. Validation of 68Ge/68Ga generator processing by chemical purification for routine clinical application of 68Ga-DOTATOC

    International Nuclear Information System (INIS)

    Asti, Mattia; De Pietri, Giovanni; Fraternali, Alessandro; Grassi, Elisa; Sghedoni, Roberto; Fioroni, Federica; Roesch, Frank; Versari, Annibale; Salvo, Diana

    2008-01-01

    Introduction: Imaging of somatostatin receptor expressing tumours has been greatly enhanced by the use of 68 Ga-DOTATOC and PET/CT. Methods: In this work, a purification method for the 68 Ge/ 68 Ga generator eluate and a method to produce 68 Ga-DOTATOC suitable for clinical use were evaluated. The generator eluate was purified and concentrated on a cation-exchange cartridge in HCl/acetone media. The efficacy of this procedure in eliminating metal impurities from the 68 Ga solution was investigated by ICP-MS. The radiotracer quality was evaluated by radio-TLC, GC and γ-ray spectrometry. Results: 68 Ga-DOTATOC preparations (n=33) were carried out with a mean synthesis yield of 59.3±2.8% (not corrected for decay) and a batch activity ranging from 555 to 296 MBq. The radiochemical and radionuclidic purity were >98% and 99.9999%, respectively. With this purification process, >95% of the Fe(III), Zn(II) and Mn(II) were eliminated from the solution. Conclusions: 68 Ga-DOTATOC produced with this method can be efficiently used in nuclear medicine departments for PET evaluations

  9. LMKB/MARF1 localizes to mRNA processing bodies, interacts with Ge-1, and regulates IFI44L gene expression.

    Directory of Open Access Journals (Sweden)

    Donald B Bloch

    Full Text Available The mRNA processing body (P-body is a cellular structure that regulates the stability of cytoplasmic mRNA. MARF1 is a murine oocyte RNA-binding protein that is associated with maintenance of mRNA homeostasis and genomic stability. In this study, autoantibodies were used to identify Limkain B (LMKB, the human orthologue of MARF1, as a P-body component. Indirect immunofluorescence demonstrated that Ge-1 (a central component of the mammalian core-decapping complex co-localized with LMKB in P-bodies. Two-hybrid and co-immunoprecipitation assays were used to demonstrate interaction between Ge-1 and LMKB. The C-terminal 120 amino acids of LMKB mediated interaction with Ge-1 and the N-terminal 1094 amino acids of Ge-1 were required for interaction with LMKB. LMKB is the first protein identified to date that interacts with this portion of Ge-1. LMKB was expressed in human B and T lymphocyte cell lines; depletion of LMKB increased expression of IFI44L, a gene that has been implicated in the cellular response to Type I interferons. The interaction between LMKB/MARF1, a protein that contains RNA-binding domains, and Ge-1, which interacts with core-decapping proteins, suggests that LMKB has a role in the regulation of mRNA stability. LMKB appears to have different functions in different cell types: maintenance of genomic stability in developing oocytes and possible dampening of the inflammatory response in B and T cells.

  10. Diffractive dissociation process π-p → π- (π-π+p) at 14 GeV/c

    International Nuclear Information System (INIS)

    Rosenfeld, C.

    1977-05-01

    An experiment in which a 14 GeV/c π - beam was incident on a hydrogen bubble chamber is described. Fast forward scattered pions traversed a wire spark chamber spectrometer downstream of the bubble chamber. Events identified as inelastic by the spectrometer induced a trigger of the bubble chamber camera. The film produced contained a heavy enrichment of events of proton diffractive dissociation. A sample from this exposure of 4400 events of the reaction π - p → π - N* → π - π - π + p was studied. In the two body mass spectra the only noteworthy feature is the Δ ++ (1230). In the N* mass spectrum one observes enhancements at 1.49 GeV, 1.72 GeV, and 2.0 GeV. For the prominent 1.72 GeV feature estimates are given of the width and cross section as well as evidence favoring a substantial branching fraction to πΔ(1230). We looked for production of N*(1470) followed by decay to πΔ(1230) with negative result. An examination of the Δ ++ (1230) decay distribution suggests that the Deck mechanism is the major contributor to the πΔ subchannel. The s-channel and t-channel helicity conservation rules were tested. One observed violent conflict with sCHC and mild conflict with tCHC. One also tested for simultaneous validity of tCHC and the Gribov--Morrison rule and found no significant contradiction with this dual hypothesis

  11. Low Thermal Conductivity of Bulk Amorphous Si1- x Ge x Containing Nano-Sized Crystalline Particles Synthesized by Ball-Milling Process

    Science.gov (United States)

    Muthusamy, Omprakash; Nishino, Shunsuke; Ghodke, Swapnil; Inukai, Manabu; Sobota, Robert; Adachi, Masahiro; Kiyama, Makato; Yamamoto, Yoshiyuki; Takeuchi, Tsunehiro; Santhanakrishnan, Harish; Ikeda, Hiroya; Hayakawa, Yasuhiro

    2018-06-01

    Amorphous Si0.65Ge0.35 powder containing a small amount of nano-sized crystalline particles was synthesized by means of the mechanical alloying process. Hot pressing for 24 h under the pressure of 400 MPa at 823 K, which is below the crystallization temperature, allowed us to obtain bulk amorphous Si-Ge alloy containing a small amount of nanocrystals. The thermal conductivity of the prepared bulk amorphous Si-Ge alloy was extremely low, showing a magnitude of less than 1.35 Wm-1 K-1 over the entire temperature range from 300 K to 700 K. The sound velocity of longitudinal and transverse waves for the bulk amorphous Si0.65Ge0.35 were measured, and the resulting values were 5841 m/s and 2840 m/s, respectively. The estimated mean free path of phonons was kept at the very small value of ˜ 4.2 nm, which was mainly due to the strong scattering limit of phonons in association with the amorphous structure.

  12. Photoluminescence and TEM evaluations of defects generated during SiGe-on-insulator virtual substrate fabrication: Temperature ramping process

    International Nuclear Information System (INIS)

    Wang, D.; Ii, S.; Ikeda, K.; Nakashima, H.; Matsumoto, K.; Nakamae, M.; Nakashima, H.

    2006-01-01

    Crystal qualities were evaluated by photoluminescence (PL) and transmission electron microscopy (TEM) for cap-Si/SiGe/Si-on-insulater (SOI) structure, which is the typical structure for SiGe-on-insulator virtual substrate fabrication using the Ge condensation by dry oxidation. The thicknesses of cap-Si, SOI and BOX layers are 10, 70, and 140 nm, respectively. We have three kinds of wafers with SiGe thicknesses of 74, 154 and 234 nm. All of the wafers were heated from 200 deg.C to a target temperature (T t ) in the range of 820-1200 deg. C with a ramping rate of 5 deg. C/min, and maintained at T t for 10 min. The air in the furnace was a mixture of O 2 and N 2 . The PL measurements were carried out using a 325 nm UV line of a continuous-wave HeCd laser. Free exciton peaks were clearly observed for the as-grown wafers and decreased with an increase in the annealing temperature. For the selected wafers, cross-sectional and plan-view TEM measurements show clear generation and variation of dislocations at the interface of SiGe/SOI according to the T t . Defect-related PL signals were observed at around 0.82, 0.88, 0.95 and 1.0 eV, which also varied according to the T t and the SiGe thickness. They were identified to dislocation-related and stacking-fault-related defects by TEM

  13. A simple semi-empirical way of accounting for the contribution of pair production process to the efficiency of Ge detectors

    International Nuclear Information System (INIS)

    Sudarshan, M.; Singh, R.

    1991-01-01

    By considering the data for a 38cm 3 Ge(Li) detector from E γ = 319.80 to 2598.80 keV, and for a 68 cm 3 HPGe detector from E γ = 223.430 to 3253.610 keV, it has been demonstrated that the contribution of the pair production process to the full energy peak efficiency (FEPE) of germanium detectors can be quite adequately accounted for in a semi-empirical way. (author)

  14. The study of production processes of nucleons, γ-quanta and neutral strange particles in pp- and pn-interactions at 300 GeV

    International Nuclear Information System (INIS)

    Turumov, Eh.

    2001-03-01

    Processes of nucleons, γ-quanta and neutral strange particles in pp- and pn-interactions at 300 GeV in 4π-geometry were studied by the use of neon-hydrogen bubble chamber. The average multiplicity of γ-quanta, fast neutrons, K 0 s -mesons and λ 0 ( λ 0 bar)-hyperons were defined and their energy spectra were analyzed. Experimental results were compared with Lund and dual parton model predictions. (author)

  15. Recent measurements of two photon muon pair process from Mark J at √s up to 46.78 GeV

    International Nuclear Information System (INIS)

    Zhang, C.C.

    1985-07-01

    The recent results from Mark J on two photon muon pair production with √s from 14 to 46.78 GeV are presented, and compared with the complete α 4 QED calculation in a large range of √s and four momentum transfer, including untagged, single and double tagged events. The forward-backward charge asymmetry of muons produced in the two photon process is also compared to the QED prediction. (orig.)

  16. Unusual effects of manual grinding and subsequent annealing process observed in Gd5.09Ge2.03Si1.88 compound

    Science.gov (United States)

    Carvalho, A. M. G.; Alves, C. S.; Trevizoli, P. V.; dos Santos, A. O.; Gama, S.; Coelho, A. A.

    2018-03-01

    The Gd5.09Ge2.03Si1.88 compound, as well as other magnetocaloric materials, certainly will not be used in their un-manufactured as-cast condition in future magnetic refrigeration applications or other devices. In this work, we have studied the Gd5.09Ge2.03Si1.88 compound processed in different ways, mainly, the as-cast powder, the annealed powder, and the pressed and sintered powder. The annealed powder (1370 K/20 h) does not present the monoclinic phase and the first-order magneto-structural transition observed in the as-cast powder. The pressed and sintered powder also do not present the first-order transition. Furthermore, the compacting pressure shifts the second-order magnetic transition to lower temperatures. The behavior of cell parameters as a function of the compacting pressure indicates that T C is directly affected by parameter c change.

  17. A measurement of the total cross section and a study of inclusive muon production for the process e+e-->hadrons in the energy range between 39.79 GeV and 46.78 GeV

    International Nuclear Information System (INIS)

    Bartel, W.; Becker, L.; Cords, D.; Eichler, R.; Felst, R.; Haidt, D.; Junge, H.; Knies, G.; Krehbiel, H.; Laurikainen, P.; Meier, K.; Meinke, R.; Naroska, B.; Olsson, J.; Schmidt, D.; Steffen, P.; Dietrich, G.; Hagemann, J.; Heinzelmann, G.; Kado, H.; Kawagoe, K.; Kleinwort, C.; Kuhlen, M.; Petersen, A.; Ramcke, R.; Schneekloth, U.; Weber, G.; Allison, J.; Ball, A.H.; Barlow, R.J.; Chrin, J.; Duerdoth, I.P.; Greenshaw, T.; Hill, P.; Loebinger, F.K.; Macbeth, A.A.; McCann, H.; Mills, H.E.; Murphy, P.G.; Stephens, K.; Warming, P.; Glasser, R.G.; Skard, J.A.J.; Wagner, S.R.; Zorn, G.T.; Cartwright, S.L.; Clarke, D.; Marshall, R.; Middleton, R.P.; Kawamoto, T.; Kobayashi, T.; Mashimo, T.; Minowa, M.; Takeda, H.; Takeshita, T.; Yamada, S.

    1985-01-01

    The total cross section and the inclusive muon cross section for the process e + e - ->hadrons have been measured in the center of mass energy range between 39.79 and 46.78 GeV. The ratio R shows no significant structure. It has an average value of 4.13+-0.08+-0.14. An upper limit is set on the production of narrow resonances. Limits are obtained for pair-produced heavy quarks. The data are compared with the standard electroweak interaction model including QCD corrections taking into account the five known types of quarks. Upper limits are given for a possible structure of quarks and for effects of color octet leptons. (orig.)

  18. Ge nanobelts with high compressive strain fabricated by secondary oxidation of self-assembly SiGe rings

    DEFF Research Database (Denmark)

    Lu, Weifang; Li, Cheng; Lin, Guangyang

    2015-01-01

    Curled Ge nanobelts were fabricated by secondary oxidation of self-assembly SiGe rings, which were exfoliated from the SiGe stripes on the insulator. The Ge-rich SiGe stripes on insulator were formed by hololithography and modified Ge condensation processes of Si0.82Ge0.18 on SOI substrate. Ge...... nanobelts under a residual compressive strain of 2% were achieved, and the strain should be higher before partly releasing through bulge islands and breakage of the curled Ge nanobelts during the secondary oxidation process. The primary factor leading to compressive strain is thermal shrinkage of Ge...... nanobelts, which extrudes to Ge nanobelts in radial and tangent directions during the cooling process. This technique is promising for application in high-mobility Ge nano-scale transistors...

  19. A flavour independent search for the Higgsstrahlung process in e+e- collisions at centre-of-mass energies from 189 to 209 GeV

    CERN Document Server

    Pascolo, J M

    2001-01-01

    Higgs boson decays to b or tau pairs, dominant in the standard model, can be suppressed in extended models. A flavour-independent search for the Higgsstrahlung process has been carried out to treat all possible hadronic decays of the Higgs boson on an equal footing. The analysis is based on the data collected by the ALEPH detector at LEP at centre-of-mass energies from 189 to 209 GeV. A 95\\% CL lower mass limit of is obtained for a cross-section equal to that of the standard model and a 100\\% hadronic branching fraction.

  20. Improved Si0.5Ge0.5/Si interface quality achieved by the process of low energy hydrogen plasma cleaning and investigation of interface quality with positron annihilation spectroscopy

    Science.gov (United States)

    Liao, M.-H.; Chen, C.-H.

    2013-04-01

    The Positron Annihilation Spectra (PAS), Raman, and Photoluminescence spectroscopy reveal that Si0.5Ge0.5/Si interface quality can be significantly improved by the low energy plasma cleaning process using hydrogen. In the PAS, the particularly small value of lifetime and intensity near the Si0.5Ge0.5/Si interface in the sample with the treatment indicate that the defect concentration is successfully reduced 2.25 times, respectively. Fewer defects existed in the Si0.5Ge0.5/Si interface result in the high compressive strain about 0.36% in the top epi-Si0.5Ge0.5 layer, which can be observed in Raman spectra and stronger radiative recombination rate about 1.39 times for the infrared emission, which can be observed in the photoluminescence spectra. With better Si0.5Ge0.5/Si interface quality, the SiGe-based devices can have better optical and electrical characteristics for more applications in the industry. The PAS is also demonstrated that it is the useful methodology tool to quantify the defect information in the SiGe-based material.

  1. Dissociative multiple photoionization of SiBr4 and GeBr4 in the VUV and X-ray regions: a comparative study of inner-shell processes involving Si(2p, 2s), Ge(3d, 3p, 3s), and Br(3d, 3p, 3s)

    International Nuclear Information System (INIS)

    Boo, Bong Hyun; Saito, Norio

    2003-01-01

    Dissociative multiple photoionization of MBr 4 (M=Si, Ge) in the Si(2p, 2s), Ge(3d, 3s, 3p), and Br(3d, 3p, 3s) inner-shell regions has been studied by using time-of-flight (TOF) mass spectrometry coupled to synchrotron radiation in the ranges of 50∼944 eV for SiBr 4 and 50∼467 eV for GeBr 4 . Total photoion and photoion-photoion coincidence (PIPICO) yields have been measured as functions of the photon energy. Here, giant shape resonances have been observed beyond the thresholds of the 3d shells owing to the Br(3d 10 )→Br(3d 9 -f) excitation, showing the similar patterns for both of the systems. The ranges and the intensities of the shape resonances are found to be tremendously broad and enhanced, respectively, by the tetrahedral arrangement of the bromine ligands. In addition to the giant resonances, we have observed discrete features corresponding to the Br(3d), Si(2p), and Si(2s) in SiBr 4 and to the Br(3d), Ge(3p), and Ge(3s) in GeBr 4 . The dissociation processes of multiply charged parent ions have also been evaluated from the variations of photoelectron-photoion coincidence (PEPICO) and PIPICO yields with the photon energy. Over the entire energies examined, most efficient PIPICO channels involve Br + -Br + , Br + -MBr + , and M + -Br + (M=Si, Ge), the formation of which indicates that the total destruction of the molecules is a dominant process in the dissociative photoionization of the molecules

  2. Uniaxially stressed Ge:Ga and Ge:Be

    Energy Technology Data Exchange (ETDEWEB)

    Dubon, Jr., Oscar Danilo [Univ. of California, Berkeley, CA (United States)

    1992-12-01

    The application of a large uniaxial stress to p-type Ge single crystals changes the character of both the valence band and the energy levels associated with the acceptors. Changes include the splitting of the fourfold degeneracy of the valence band top and the reduction of the ionization energy of shallow acceptors. In order to study the effect of uniaxial stress on transport properties of photoexcited holes, a variable temperature photo-Hall effect system was built in which stressed Ge:Ga and Ge:Be could be characterized. Results indicate that stress increases the lifetime and Hall mobility of photoexcited holes. These observations may help further the understanding of fundamental physical processes that affect the performance of stressed Ge photoconductors including the capture of holes by shallow acceptors.

  3. Investigation on the dominant key to achieve superior Ge surface passivation by GeOx based on the ozone oxidation

    International Nuclear Information System (INIS)

    Wang, Xiaolei; Xiang, Jinjuan; Wang, Wenwu; Xiong, Yuhua; Zhang, Jing; Zhao, Chao

    2015-01-01

    Highlights: • The dominant key to achieve superior Ge passivation by GeO x is investigated. • The interface state density decreases with increasing the GeO x thickness. • The Ge 3+ oxide component is the dominant key to passivate the Ge surface. • The atomic structure at the GeO x /Ge interface is built by XPS. - Abstract: The dominant key to achieve superior Ge surface passivation by GeO x interfacial layer is investigated based on ozone oxidation. The interface state density (D it ) measured from low temperature conduction method is found to decrease with increasing the GeO x thickness (0.26–1.06 nm). The X-ray photoelectron spectroscopy (XPS) is employed to demonstrate the interfacial structure of GeO x /Ge with different GeO x thicknesses. And the XPS results show that Ge 3+ oxide component is responsible to the decrease of the D it due to the effective passivation of Ge dangling bonds. Therefore, the formation of Ge 3+ component is the dominant key to achieve low D it for Ge gate stacks. Our work confirms that the same physical mechanism determines the Ge surface passivation by the GeO x regardless of the oxidation methods to grow the GeO x interfacial layer. As a result, to explore a growth process that can realize sufficient Ge 3+ component in the GeO x interlayer as thin as possible is important to achieve both equivalent oxide thickness scaling and superior interfacial property simultaneously. This conclusion is helpful to engineer the optimization of the Ge gate stacks.

  4. Self organized formation of Ge nanocrystals in multilayers

    OpenAIRE

    Zschintzsch-Dias, Manuel

    2012-01-01

    The aim of this work is to create a process which allows the tailored growth of Ge nanocrystals for use in photovoltic applications. The multilayer systems used here provide a reliable method to control the Ge nanocrystal size after phase separation. In this thesis, the deposition of GeOx/SiO2 and Ge:SiOx~ 2/SiO2 multilayers via reactive dc magnetron sputtering and the self-ordered Ge nanocrystal formation within the GeOx and Ge:SiOx~ 2 sublayers during subsequent annealing is investigated...

  5. Fast preparation of Bi2GeO5 nanoflakes via a microwave-hydrothermal process and enhanced photocatalytic activity after loading with Ag nanoparticles

    International Nuclear Information System (INIS)

    Li, Zhao-Qian; Lin, Xin-Shan; Zhang, Lei; Chen, Xue-Tai; Xue, Zi-Ling

    2012-01-01

    Highlights: ► Bi 2 GeO 5 nanoflakes were successfully synthesized via a microwave-assisted solution-phase approach. ► Ag nanoparticles were deposited on the Bi 2 GeO 5 nanoflakes by a photoreduction procedure. ► Catalytic activity of the Ag/Bi 2 GeO 5 nanocomposite in the photo-degradation of rhodamine B (RhB) was much higher than that of pure Bi 2 GeO 5 . -- Abstract: In this work, a facile and rapid microwave-assisted hydrothermal route has been developed to prepare Bi 2 GeO 5 nanoflakes. Ag nanoparticles were subsequently deposited on the Bi 2 GeO 5 nanoflakes by a photoreduction procedure. The phases and morphologies of the products were characterized by powder X-ray diffraction (XRD), X-ray photoelectron spectrum (XPS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and UV–vis diffuse reflectance spectroscopy. Photocatalytic experiments indicate that such Ag/Bi 2 GeO 5 nanocomposite possesses higher photocatalytic activity for RhB degradation under UV light irradiation in comparison to pure Bi 2 GeO 5 . The amount of Ag in the nanocomposite affects the catalytic activity, and 3 wt% Ag showed the highest photodegradation efficiency. Moreover, the catalyst remains active after four consecutive tests. The present study provides a new strategy to design composite materials with enhanced photocatalytic activity.

  6. Effect of Ge Content on the Formation of Ge Nanoclusters in Magnetron-Sputtered GeZrOx-Based Structures.

    Science.gov (United States)

    Khomenkova, L; Lehninger, D; Kondratenko, O; Ponomaryov, S; Gudymenko, O; Tsybrii, Z; Yukhymchuk, V; Kladko, V; von Borany, J; Heitmann, J

    2017-12-01

    Ge-rich ZrO 2 films, fabricated by confocal RF magnetron sputtering of pure Ge and ZrO 2 targets in Ar plasma, were studied by multi-angle laser ellipsometry, Raman scattering, Auger electron spectroscopy, Fourier transform infrared spectroscopy, and X-ray diffraction for varied deposition conditions and annealing treatments. It was found that as-deposited films are homogeneous for all Ge contents, thermal treatment stimulated a phase separation and a formation of crystalline Ge and ZrO 2 . The "start point" of this process is in the range of 640-700 °C depending on the Ge content. The higher the Ge content, the lower is the temperature necessary for phase separation, nucleation of Ge nanoclusters, and crystallization. Along with this, the crystallization temperature of the tetragonal ZrO 2 exceeds that of the Ge phase, which results in the formation of Ge crystallites in an amorphous ZrO 2 matrix. The mechanism of phase separation is discussed in detail.

  7. The effect of Ge precursor on the heteroepitaxy of Ge1-x Sn x epilayers on a Si (001) substrate

    Science.gov (United States)

    Jahandar, Pedram; Weisshaupt, David; Colston, Gerard; Allred, Phil; Schulze, Jorg; Myronov, Maksym

    2018-03-01

    The heteroepitaxial growth of Ge1-x Sn x on a Si (001) substrate, via a relaxed Ge buffer, has been studied using two commonly available commercial Ge precursors, Germane (GeH4) and Digermane (Ge2H6), by means of chemical vapour deposition at reduced pressures (RP-CVD). Both precursors demonstrate growth of strained and relaxed Ge1-x Sn x epilayers, however Sn incorporation is significantly higher when using the more reactive Ge2H6 precursor. As Ge2H6 is significantly more expensive, difficult to handle or store than GeH4, developing high Sn content epilayers using the latter precursor is of great interest. This study demonstrates the key differences between the two precursors and offers routes to process optimisation which will enable high Sn content alloys at relatively low cost.

  8. Study of Si-Ge interdiffusion with phosphorus doping

    KAUST Repository

    Cai, Feiyang; Anjum, Dalaver H.; Zhang, Xixiang; Xia, Guangrui

    2016-01-01

    Si-Ge interdiffusion with phosphorus doping was investigated by both experiments and modeling. Ge/Si1-x Ge x/Ge multi-layer structures with 0.75Ge<1, a mid-1018 to low-1019 cm−3 P doping, and a dislocation density of 108 to 109 cm−2 range were studied. The P-doped sample shows an accelerated Si-Ge interdiffusivity, which is 2–8 times of that of the undoped sample. The doping dependence of the Si-Ge interdiffusion was modelled by a Fermi-enhancement factor. The results show that the Si-Ge interdiffusion coefficient is proportional to n2/n2i for the conditions studied, which indicates that the interdiffusion in a high Ge fraction range with n-type doping is dominated by V2− defects. The Fermi-enhancement factor was shown to have a relatively weak dependence on the temperature and the Ge fraction. The results are relevant to the structure and thermal processing condition design of n-type doped Ge/Si and Ge/SiGe based devices such as Ge/Si lasers.

  9. Study of Si-Ge interdiffusion with phosphorus doping

    KAUST Repository

    Cai, Feiyang

    2016-10-28

    Si-Ge interdiffusion with phosphorus doping was investigated by both experiments and modeling. Ge/Si1-x Ge x/Ge multi-layer structures with 0.75Ge<1, a mid-1018 to low-1019 cm−3 P doping, and a dislocation density of 108 to 109 cm−2 range were studied. The P-doped sample shows an accelerated Si-Ge interdiffusivity, which is 2–8 times of that of the undoped sample. The doping dependence of the Si-Ge interdiffusion was modelled by a Fermi-enhancement factor. The results show that the Si-Ge interdiffusion coefficient is proportional to n2/n2i for the conditions studied, which indicates that the interdiffusion in a high Ge fraction range with n-type doping is dominated by V2− defects. The Fermi-enhancement factor was shown to have a relatively weak dependence on the temperature and the Ge fraction. The results are relevant to the structure and thermal processing condition design of n-type doped Ge/Si and Ge/SiGe based devices such as Ge/Si lasers.

  10. Junction-less poly-Ge FinFET and charge-trap NVM fabricated by laser-enabled low thermal budget processes

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Wen-Hsien; Shen, Chang-Hong; Wang, Hsing-Hsiang; Yang, Chih-Chao; Hsieh, Tung-Ying; Hsieh, Jin-Long; Yeh, Wen-Kuan [National Nano Device Laboratories, No. 26, Prosperity Road 1, Hsinchu 30078, Taiwan (China); Shieh, Jia-Min, E-mail: jmshieh@narlabs.org.tw, E-mail: jmshieh@faculty.nctu.edu.tw [National Nano Device Laboratories, No. 26, Prosperity Road 1, Hsinchu 30078, Taiwan (China); Departments of Photonics and Institute of Electro-Optical Engineering, National Chiao-Tung University, Hsinchu 30010, Taiwan (China); Huang, Tzu-En [Departments of Photonics and Institute of Electro-Optical Engineering, National Chiao-Tung University, Hsinchu 30010, Taiwan (China)

    2016-06-13

    A doping-free poly-Ge film as channel material was implemented by CVD-deposited nano-crystalline Ge and visible-light laser crystallization, which behaves as a p-type semiconductor, exhibiting holes concentration of 1.8 × 10{sup 18 }cm{sup −3} and high crystallinity (Raman FWHM ∼ 4.54 cm{sup −1}). The fabricated junctionless 7 nm-poly-Ge FinFET performs at an I{sub on}/I{sub off} ratio over 10{sup 5} and drain-induced barrier lowering of 168 mV/V. Moreover, the fast programming speed of 100 μs–1 ms and reliable retention can be obtained from the junctionless poly-Ge nonvolatile-memory. Such junctionless poly-Ge devices with low thermal budget are compatible with the conventional CMOS technology and are favorable for 3D sequential-layer integration and flexible electronics.

  11. Influence of the crystallization process on the luminescence of multilayers of SiGe nanocrystals embedded in SiO2

    International Nuclear Information System (INIS)

    Avella, M.; Prieto, A.C.; Jimenez, J.; Rodriguez, A.; Sangrador, J.; Rodriguez, T.; Ortiz, M.I.; Ballesteros, C.

    2008-01-01

    Multilayers of SiGe nanocrystals embedded in an oxide matrix have been fabricated by low-pressure chemical vapor deposition of SiGe and SiO 2 onto Si wafers (in a single run at 390 deg. C and 50 mTorr, using GeH 4 , Si 2 H 6 and O 2 ) followed by a rapid thermal annealing treatment to crystallize the SiGe nanoparticles. The main emission band is located at 400 nm in both cathodoluminescence and photoluminescence experiments at 80 K and also at room temperature. The annealing conditions (temperatures ranging from 700 to 1000 deg. C and for times of 30 and 60 s) have been investigated in samples with different diameter of the nanoparticles (from ∼3 to ≥5 nm) and oxide interlayer thickness (15 and 35 nm) in order to establish a correlation between the crystallization of the nanoparticles, the degradation of their composition by Ge diffusion and the intensity of the luminescence emission band. Structures with small nanoparticles (3-4.5 nm) separated by thick oxide barriers (∼35 nm) annealed at 900 deg. C for 60 s yield the maximum intensity of the luminescence. An additional treatment at 450 deg. C in forming gas for dangling-bond passivation increases the intensity of the luminescence band by 25-30%

  12. Single-fabrication-step Ge nanosphere/SiO2/SiGe heterostructures: a key enabler for realizing Ge MOS devices

    Science.gov (United States)

    Liao, P. H.; Peng, K. P.; Lin, H. C.; George, T.; Li, P. W.

    2018-05-01

    We report channel and strain engineering of self-organized, gate-stacking heterostructures comprising Ge-nanosphere gate/SiO2/SiGe-channels. An exquisitely-controlled dynamic balance between the concentrations of oxygen, Si, and Ge interstitials was effectively exploited to simultaneously create these heterostructures in a single oxidation step. Process-controlled tunability of the channel length (5–95 nm diameters for the Ge-nanospheres), gate oxide thickness (2.5–4.8 nm), as well as crystal orientation, chemical composition and strain engineering of the SiGe-channel was achieved. Single-crystalline (100) Si1‑x Ge x shells with Ge content as high as x = 0.85 and with a compressive strain of 3%, as well as (110) Si1‑x Ge x shells with Ge content of x = 0.35 and corresponding compressive strain of 1.5% were achieved. For each crystal orientation, our high Ge-content, highly-stressed SiGe shells feature a high degree of crystallinity and thus, provide a core ‘building block’ required for the fabrication of Ge-based MOS devices.

  13. Structural Analyses of Phase Stability in Amorphous and Partially Crystallized Ge-Rich GeTe Films Prepared by Atomic Layer Deposition.

    Science.gov (United States)

    Gwon, Taehong; Mohamed, Ahmed Yousef; Yoo, Chanyoung; Park, Eui-Sang; Kim, Sanggyun; Yoo, Sijung; Lee, Han-Koo; Cho, Deok-Yong; Hwang, Cheol Seong

    2017-11-29

    The local bonding structures of Ge x Te 1-x (x = 0.5, 0.6, and 0.7) films prepared through atomic layer deposition (ALD) with Ge(N(Si(CH 3 ) 3 ) 2 ) 2 and ((CH 3 ) 3 Si) 2 Te precursors were investigated using Ge K-edge X-ray absorption spectroscopy (XAS). The results of the X-ray absorption fine structure analyses show that for all of the compositions, the as-grown films were amorphous with a tetrahedral Ge coordination of a mixture of Ge-Te and Ge-Ge bonds but without any signature of Ge-GeTe decomposition. The compositional evolution in the valence band electronic structures probed through X-ray photoelectron spectroscopy suggests a substantial chemical influence of additional Ge on the nonstoichiometric GeTe. This implies that the ALD process can stabilize Ge-abundant bonding networks like -Te-Ge-Ge-Te- in amorphous GeTe. Meanwhile, the XAS results on the Ge-rich films that had undergone post-deposition annealing at 350 °C show that the parts of the crystalline Ge-rich GeTe became separated into Ge crystallites and rhombohedral GeTe in accordance with the bulk phase diagram, whereas the disordered GeTe domains still remained, consistent with the observations of transmission electron microscopy and Raman spectroscopy. Therefore, amorphousness in GeTe may be essential for the nonsegregated Ge-rich phases and the low growth temperature of the ALD enables the achievement of the structurally metastable phases.

  14. Fabrication of Ge-on-insulator wafers by Smart-CutTM with thermal management for undamaged donor Ge wafers

    Science.gov (United States)

    Kim, Munho; Cho, Sang June; Jayeshbhai Dave, Yash; Mi, Hongyi; Mikael, Solomon; Seo, Jung-Hun; Yoon, Jung U.; Ma, Zhenqiang

    2018-01-01

    Newly engineered substrates consisting of semiconductor-on-insulator are gaining much attention as starting materials for the subsequent transfer of semiconductor nanomembranes via selective etching of the insulating layer. Germanium-on-insulator (GeOI) substrates are critically important because of the versatile applications of Ge nanomembranes (Ge NMs) toward electronic and optoelectronic devices. Among various fabrication techniques, the Smart-CutTM technique is more attractive than other methods because a high temperature annealing process can be avoided. Another advantage of Smart-CutTM is the reusability of the donor Ge wafer. However, it is very difficult to realize an undamaged Ge wafer because there exists a large mismatch in the coefficient of thermal expansion among the layers. Although an undamaged donor Ge wafer is a prerequisite for its reuse, research related to this issue has not yet been reported. Here we report the fabrication of 4-inch GeOI substrates using the direct wafer bonding and Smart-CutTM process with a low thermal budget. In addition, a thermo-mechanical simulation of GeOI was performed by COMSOL to analyze induced thermal stress in each layer of GeOI. Crack-free donor Ge wafers were obtained by annealing at 250 °C for 10 h. Raman spectroscopy and x-ray diffraction (XRD) indicated similarly favorable crystalline quality of the Ge layer in GeOI compared to that of bulk Ge. In addition, Ge p-n diodes using transferred Ge NM indicate a clear rectifying behavior with an on and off current ratio of 500 at ±1 V. This demonstration offers great promise for high performance transferrable Ge NM-based device applications.

  15. Bi surfactant mediated growth for fabrication of Si/Ge nanostructures and investigation of Si/Ge intermixing by STM

    Energy Technology Data Exchange (ETDEWEB)

    Paul, N.

    2007-10-26

    In the thesis work presented here, we show that Bi is more promising surfactant material than Sb. We demonstrate that by using Bi as a terminating layer on Ge/Si surface, it is possible to distinguish between Si and Ge in Scanning tunnelling microscope (STM). Any attempt to utilize surfactant mediated growth must be preceded by a thorough study of its effect on the the system being investigated. Thus, the third chapter of this thesis deals with an extensive study of the Bi surfactant mediated growth of Ge on Si(111) surface as a function of Ge coverage. The growth is investigated from the single bilayer Ge coverage till the Ge coverage of about 15 BL when the further Ge deposition leads to two-dimensional growth. In the fourth chapter, the unique property of Bi terminating layer on Ge/Si surface to result in an STM height contrast between Si and Ge is explained with possible explanations given for the reason of this apparent height contrast. The controlled fabrication of Ge/Si nanostructures such as nanowires and nanorings is demonstrated. A study on Ge-Si diffusion in the surface layers by a direct method such as STM was impossible previously because of the similar electronic structure of Ge and Si. Since with the Bi terminating surface layer, one is able to distinguish between Ge and Si, the study of intermixing between them is also possible using STM. This method to distinguish between Si and Ge allows one to study intermixing on the nanoscale and to identify the fundamental diffusion processes giving rise to the intermixing. In Chapter 5 we discuss how this could prove useful especially as one could get a local probe over a very narrow Ge-Si interface. A new model is proposed to estimate change in the Ge concentration in the surface layer with time. The values of the activation energies of Ge/Si exchange and Si/Ge exchange are estimated by fitting the experimental data with the model. The Ge/Si intermixing has been studied on a surface having 1 ML Bi ({radical

  16. The dependency of different stress-level SiN capping films and the optimization of D-SMT process for the device performance booster in Ge n-FinFETs

    Energy Technology Data Exchange (ETDEWEB)

    Liao, M.-H., E-mail: mhliaoa@ntu.edu.tw; Chen, P.-G. [Department of Mechanical Engineering, National Taiwan University, Taipei 10617, Taiwan (China)

    2015-08-17

    The capping stressed SiN film is one of the most important process steps for the dislocation stress memorization technique (D-SMT), which has been used widely in the current industry, for the electron mobility booster in the n-type transistor beyond the 32/28 nm technology node. In this work, we found that the different stress-level SiN capping films influence the crystal re-growth velocities along different directions including [100] and [110] directions in Ge a lot. It can be further used to optimize the dislocation angle in the transistor during the D-SMT process and then results in the largest channel stress distribution to boost the device performance in the Ge n-FinFETs. Based on the theoretical calculation and experimental demonstration, it shows that the Ge three dimensional (3D) n-FinFETs device performance is improved ∼55% with the usage of +3 GPa tensile stressed SiN capping film. The channel stress and dislocation angle is ∼2.5 GPa and 30°, measured by the atomic force microscope-Raman technique and transmission electron microscopy, respectively.

  17. Gate-stack engineering for self-organized Ge-dot/SiO2/SiGe-shell MOS capacitors

    Directory of Open Access Journals (Sweden)

    Wei-Ting eLai

    2016-02-01

    Full Text Available We report the first-of-its-kind, self-organized gate-stack heterostructure of Ge-dot/SiO2/SiGe-shell on Si fabricated in a single step through the selective oxidation of a SiGe nano-patterned pillar over a Si3N4 buffer layer on a Si substrate. Process-controlled tunability of the Ge-dot size (7.5−90 nm, the SiO2 thickness (3−4 nm, and as well the SiGe-shell thickness (2−15 nm has been demonstrated, enabling a practically-achievable core building block for Ge-based metal-oxide-semiconductor (MOS devices. Detailed morphologies, structural, and electrical interfacial properties of the SiO2/Ge-dot and SiO2/SiGe interfaces were assessed using transmission electron microscopy, energy dispersive x-ray spectroscopy, and temperature-dependent high/low-frequency capacitance-voltage measurements. Notably, NiGe/SiO2/SiGe and Al/SiO2/Ge-dot/SiO2/SiGe MOS capacitors exhibit low interface trap densities of as low as 3-5x10^11 cm^-2·eV^-1 and fixed charge densities of 1-5x10^11 cm^-2, suggesting good-quality SiO2/SiGe-shell and SiO2/Ge-dot interfaces. In addition, the advantage of having single-crystalline Si1-xGex shell (x > 0.5 in a compressive stress state in our self-aligned gate-stack heterostructure has great promise for possible SiGe (or Ge MOS nanoelectronic and nanophotonic applications.

  18. Water-vapor-enhanced growth of Ge-GeOx core-shell nanowires and Si1-xGexOy nanowires

    International Nuclear Information System (INIS)

    Hsu, T-J; Ko, C-Y; Lin, W-T

    2007-01-01

    The effects of moist Ar on the growth of Ge-GeO x core-shell nanowires (Ge-GeO x NWs) and Si 1-x Ge x O y nanowires (SiGeONWs) on Si substrates without adding a metal catalyst via the carbothermal reduction of GeO 2 powders at 1100 deg. C were studied. No significant nanowires were grown in dry Ar at a flow rate of 100-300 sccm until a bit of water in the range of 0.5-2 ml was loaded into the furnace. More water suppressed the growth of nanowires because of the exhaustion of more graphite powder. The growth of Ge-GeO x NWs and SiGeONWs follows the vapor-solid and vapor-liquid-solid processes, respectively. The present study showed that the water vapor serves as an oxidizer as well as a reducer at 1100 deg. C in enhancing the growth of SiGeONWs and Ge-GeO x NWs, respectively. The growth mechanisms of Ge-GeO x NWs and SiGeONWs are also discussed

  19. The Effects of Annealing Temperatures on Composition and Strain in Si x Ge1-x Obtained by Melting Growth of Electrodeposited Ge on Si (100).

    Science.gov (United States)

    Abidin, Mastura Shafinaz Zainal; Morshed, Tahsin; Chikita, Hironori; Kinoshita, Yuki; Muta, Shunpei; Anisuzzaman, Mohammad; Park, Jong-Hyeok; Matsumura, Ryo; Mahmood, Mohamad Rusop; Sadoh, Taizoh; Hashim, Abdul Manaf

    2014-02-24

    The effects of annealing temperatures on composition and strain in Si x Ge 1- x , obtained by rapid melting growth of electrodeposited Ge on Si (100) substrate were investigated. Here, a rapid melting process was performed at temperatures of 1000, 1050 and 1100 °C for 1 s. All annealed samples show single crystalline structure in (100) orientation. A significant appearance of Si-Ge vibration mode peak at ~400 cm -1 confirms the existence of Si-Ge intermixing due to out-diffusion of Si into Ge region. On a rapid melting process, Ge melts and reaches the thermal equilibrium in short time. Si at Ge/Si interface begins to dissolve once in contact with the molten Ge to produce Si-Ge intermixing. The Si fraction in Si-Ge intermixing was calculated by taking into account the intensity ratio of Ge-Ge and Si-Ge vibration mode peaks and was found to increase with the annealing temperatures. It is found that the strain turns from tensile to compressive as the annealing temperature increases. The Si fraction dependent thermal expansion coefficient of Si x Ge 1- x is a possible cause to generate such strain behavior. The understanding of compositional and strain characteristics is important in Ge/Si heterostructure as these properties seem to give significant effects in device performance.

  20. The Effects of Annealing Temperatures on Composition and Strain in SixGe1−x Obtained by Melting Growth of Electrodeposited Ge on Si (100)

    Science.gov (United States)

    Abidin, Mastura Shafinaz Zainal; Morshed, Tahsin; Chikita, Hironori; Kinoshita, Yuki; Muta, Shunpei; Anisuzzaman, Mohammad; Park, Jong-Hyeok; Matsumura, Ryo; Mahmood, Mohamad Rusop; Sadoh, Taizoh; Hashim, Abdul Manaf

    2014-01-01

    The effects of annealing temperatures on composition and strain in SixGe1−x, obtained by rapid melting growth of electrodeposited Ge on Si (100) substrate were investigated. Here, a rapid melting process was performed at temperatures of 1000, 1050 and 1100°C for 1 s. All annealed samples show single crystalline structure in (100) orientation. A significant appearance of Si-Ge vibration mode peak at ~00 cm−1 confirms the existence of Si-Ge intermixing due to out-diffusion of Si into Ge region. On a rapid melting process, Ge melts and reaches the thermal equilibrium in short time. Si at Ge/Si interface begins to dissolve once in contact with the molten Ge to produce Si-Ge intermixing. The Si fraction in Si-Ge intermixing was calculated by taking into account the intensity ratio of Ge-Ge and Si-Ge vibration mode peaks and was found to increase with the annealing temperatures. It is found that the strain turns from tensile to compressive as the annealing temperature increases. The Si fraction dependent thermal expansion coefficient of SixGe1−x is a possible cause to generate such strain behavior. The understanding of compositional and strain characteristics is important in Ge/Si heterostructure as these properties seem to give significant effects in device performance. PMID:28788521

  1. The Effects of Annealing Temperatures on Composition and Strain in SixGe1−x Obtained by Melting Growth of Electrodeposited Ge on Si (100

    Directory of Open Access Journals (Sweden)

    Mastura Shafinaz Zainal Abidin

    2014-02-01

    Full Text Available The effects of annealing temperatures on composition and strain in SixGe1−x, obtained by rapid melting growth of electrodeposited Ge on Si (100 substrate were investigated. Here, a rapid melting process was performed at temperatures of 1000, 1050 and 1100 °C for 1 s. All annealed samples show single crystalline structure in (100 orientation. A significant appearance of Si-Ge vibration mode peak at ~400 cm−1 confirms the existence of Si-Ge intermixing due to out-diffusion of Si into Ge region. On a rapid melting process, Ge melts and reaches the thermal equilibrium in short time. Si at Ge/Si interface begins to dissolve once in contact with the molten Ge to produce Si-Ge intermixing. The Si fraction in Si-Ge intermixing was calculated by taking into account the intensity ratio of Ge-Ge and Si-Ge vibration mode peaks and was found to increase with the annealing temperatures. It is found that the strain turns from tensile to compressive as the annealing temperature increases. The Si fraction dependent thermal expansion coefficient of SixGe1−x is a possible cause to generate such strain behavior. The understanding of compositional and strain characteristics is important in Ge/Si heterostructure as these properties seem to give significant effects in device performance.

  2. Ge extraction from gasification fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Oriol Font; Xavier Querol; Angel Lopez-Soler; Jose M. Chimenos; Ana I. Fernandez; Silvia Burgos; Francisco Garcia Pena [Institute of Earth Sciences ' Jaume Almera' , Barcelona (Spain)

    2005-08-01

    Water-soluble germanium species (GeS{sub 2}, GeS and hexagonal-GeO{sub 2}) are generated during coal gasification and retained in fly ash. This fact together with the high market value of this element and the relatively high contents in the fly ashes of the Puertollano Integrated Gasification in Combined Cycle (IGCC) plant directed our research towards the development of an extraction process for this element. Major objectives of this research was to find a low cost and environmentally suitable process. Several water based extraction tests were carried out using different Puertollano IGCC fly ash samples, under different temperatures, water/fly ash ratios, and extraction times. High Ge extraction yields (up to 84%) were obtained at room temperature (25{sup o}C) but also high proportions of other trace elements (impurities) were simultaneously extracted. Increasing the extraction temperature to 50, 90 and 150{sup o}C, Ge extraction yields were kept at similar levels, while reducing the content of impurities, the water/fly ash ratio and extraction time. The experimental data point out the influence of chloride, calcium and sulphide dissolutions on the Ge extraction. 16 refs., 9 figs., 6 tabs.

  3. Triple-Regge analysis of the fragmentation processes p→sup(K-)μ+ and K-→sup(p)μ+ at 4.2 GeV/c

    International Nuclear Information System (INIS)

    Blokzijl, R.; Kluyver, J.C.; Wolters, G.F.; Metzger, W.J.; Kittel, E.W.; Shephard, W.D.; Grossman, P.; Lamb, P.

    1977-01-01

    The inclusive production of μ + in K - p interactions at 4.2 GeV/c has been studied. Both the target fragmentation of the proton into μ + and the beam fragmentation of the kaon into μ + have been analyzed with a triple-Regge model. In the pμ-bar + channel an effective exchange trajectory has been obtained which lies between the K and K(890) trajectories. For the K - μ-bar + channel a trajectory is found which may be interpreted as a δ trajectory lowered by one-half. (author)

  4. Addition of Mn to Ge quantum dot surfaces—interaction with the Ge QD {105} facet and the Ge(001) wetting layer

    International Nuclear Information System (INIS)

    Nolph, C A; Kassim, J K; Floro, J A; Reinke, P

    2013-01-01

    The interaction of Mn with Ge quantum dots (QD), which are bounded by {105} facets, and the strained Ge wetting layer (WL), terminated by a (001) surface, is investigated with scanning tunneling microscopy (STM). These surfaces constitute the growth surfaces in the growth of Mn-doped QDs. Mn is deposited on the Ge QD and WL surface in sub-monolayer concentrations, and subsequently annealed up to a temperature of 400 ° C. The changes in bonding and surface topography are measured with STM during the annealing process. Mn forms flat islands on the Ge{105} facet, whose shape and position are guided by the rebonded step reconstruction of the facet. Voltage-dependent STM images reflect the Mn-island interaction with the empty and filled states of the Ge{105} reconstruction. Scanning tunneling spectra (STS) of the Ge{105} facet and as-deposited Mn-islands show a bandgap of 0.8 eV, and the Mn-island spectra are characterized by an additional empty state at about 1.4 eV. A statistical analysis of Mn-island shape and position on the QD yields a slight preference for edge positions, whereas the QD strain field does not impact Mn-island position. However, the formation of ultra-small Mn-clusters dominates on the Ge(001) WL, which is in contrast to Mn interaction with unstrained Ge(001) surfaces. Annealing to T 5 Ge 3 from a mass balance analysis. This reaction is accompanied by the disappearance of the original Mn-surface structures and de-wetting of Mn is complete. This study unravels the details of Mn–Ge interactions, and demonstrates the role of surface diffusion as a determinant in the growth of Mn-doped Ge materials. Surface doping of Ge-nanostructures at lower temperatures could provide a pathway to control magnetism in the Mn–Ge system. (paper)

  5. Optical transitions in Ge/SiGe multiple quantum wells with Ge-rich barriers

    Science.gov (United States)

    Bonfanti, M.; Grilli, E.; Guzzi, M.; Virgilio, M.; Grosso, G.; Chrastina, D.; Isella, G.; von Känel, H.; Neels, A.

    2008-07-01

    Direct-gap and indirect-gap transitions in strain-compensated Ge/SiGe multiple quantum wells with Ge-rich SiGe barriers have been studied by optical transmission spectroscopy and photoluminescence experiments. An sp3d5s∗ tight-binding model has been adopted to interpret the experimental results. Photoluminescence spectra and their comparison with theoretical calculations prove the existence of type-I band alignment in compressively strained Ge quantum wells grown on relaxed Ge-rich SiGe buffers. The high quality of the transmission spectra opens up other perspectives for application of these structures in near-infrared optical modulators.

  6. Growth of Ge films by cluster beam deposition

    CERN Document Server

    Xu, J L; Feng, J Y

    2002-01-01

    Ge epitaxial layers with reasonable quality were grown on the Si(1 1 1) substrates by cluster beam deposition (CBD) process. The growth temperature plays a dominant role in the epitaxial growth of Ge films. The substrate temperature for epitaxial growth is about 500 deg. C, which is lower than the reported critical temperature of Ge epitaxial growth by MBE and CVD. A stress induced phase transition of Ge lattice from cubic to tetragonal is also observed in the CBD process, and the mechanism is discussed.

  7. Comparison of optical transients during the picosecond laser pulse-induced crystallization of GeSbTe and AgInSbTe phase-change thin films: Nucleation-driven versus growth-driven processes

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Guangfei [Key Laboratory of High Power Laser Materials, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); Li, Simian [State Key Laboratory of Optoelectronic Materials and Technology, Department of Physics, Sun Yat-Sen University, Guangzhou 510275 (China); Huang, Huan [Key Laboratory of High Power Laser Materials, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); Wang, Yang, E-mail: ywang@siom.ac.cn [Key Laboratory of High Power Laser Materials, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); Lai, Tianshu, E-mail: stslts@mail.sysu.edu.cn [State Key Laboratory of Optoelectronic Materials and Technology, Department of Physics, Sun Yat-Sen University, Guangzhou 510275 (China); Wu, Yiqun [Key Laboratory of High Power Laser Materials, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China)

    2013-09-01

    Direct comparison of the real-time in-situ crystallization behavior of as-deposited amorphous Ge{sub 2}Sb{sub 2}Te{sub 5} (GeSbTe) and Ag{sub 8}In{sub 14}Sb{sub 55}Te{sub 23} (AgInSbTe) phase-change thin films driven by picosecond laser pulses was performed by a time-resolved optical pump-probe technique with nanosecond resolution. Different optical transients showed various crystallization processes because of the dissimilar nucleation- and growth-dominated mechanisms of the two materials. The effects of laser pulse fluence, thermal conductive structure, and successive pulse irradiation on their crystallization dynamics were also discussed. A schematic was then established to describe the different crystallization processes beginning from the as-deposited amorphous state. The results may provide further insight into the phase-change mechanism under extra-non-equilibrium conditions and aid the development of ultrafast phase-change memory materials.

  8. Growth and evolution of nickel germanide nanostructures on Ge(001)

    International Nuclear Information System (INIS)

    Grzela, T; Capellini, G; Schubert, M A; Schroeder, T; Koczorowski, W; Czajka, R; Curson, N J; Heidmann, I; Schmidt, Th; Falta, J

    2015-01-01

    Nickel germanide is deemed an excellent material system for low resistance contact formation for future Ge device modules integrated into mainstream, Si-based integrated circuit technologies. In this study, we present a multi-technique experimental study on the formation processes of nickel germanides on Ge(001). We demonstrate that room temperature deposition of ∼1 nm of Ni on Ge(001) is realized in the Volmer–Weber growth mode. Subsequent thermal annealing results first in the formation of a continuous Ni_xGe_y wetting layer featuring well-defined terrace morphology. Upon increasing the annealing temperature to 300 °C, we observed the onset of a de-wetting process, characterized by the appearance of voids on the Ni_xGe_y terraces. Annealing above 300 °C enhances this de-wetting process and the surface evolves gradually towards the formation of well-ordered, rectangular Ni_xGe_y 3D nanostructures. Annealing up to 500 °C induces an Ostwald ripening phenomenon, with smaller nanoislands disappearing and larger ones increasing their size. Subsequent annealing to higher temperatures drives the Ni-germanide diffusion into the bulk and the consequent formation of highly ordered, {111} faceted Ni-Ge nanocrystals featuring an epitaxial relationship with the substrate Ni-Ge (101); (010) || Ge(001); (110). (paper)

  9. Energy levels of germanium, Ge I through Ge XXXII

    International Nuclear Information System (INIS)

    Sugar, J.; Musgrove, A.

    1993-01-01

    Atomic energy levels of germanium have been compiled for all stages of ionization for which experimental data are available. No data have yet been published for Ge VIII through Ge XIII and Ge XXXII. Very accurate calculated values are compiled for Ge XXXI and XXXII. Experimental g-factors and leading percentages from calculated eigenvectors of levels are given. A value for the ionization energy, either experimental when available or theoretical, is included for the neutral atom and each ion. section

  10. HP Ge planar detectors

    International Nuclear Information System (INIS)

    Gornov, M.G.; Gurov, Yu.B.; Soldatov, A.M.; Osipenko, B.P.; Yurkowski, J.; Podkopaev, O.I.

    1989-01-01

    Parameters of planar detectors manufactured of HP Ge are presented. The possibilities to use multilayer spectrometers on the base of such semiconductor detectors for nuclear physics experiments are discussed. It is shown that the obtained detectors including high square ones have spectrometrical characteristics close to limiting possible values. 9 refs.; 3 figs.; 1 tab

  11. Growth Mechanism and Surface Structure of Ge Nanocrystals Prepared by Thermal Annealing of Cosputtered GeSiO Ternary Precursor

    Directory of Open Access Journals (Sweden)

    Bo Zhang

    2014-01-01

    Full Text Available Ge nanocrystals (Ge-ncs embedded in a SiO2 superlattice structure were prepared by magnetron cosputtering and postdeposition annealing. The formation of spherical nanocrystals was confirmed by transmission electron microscopy and their growth process was studied by a combination of spectroscopic techniques. The crystallinity volume fraction of Ge component was found to increase with crystallite size, but its overall low values indicated a coexistence of crystalline and noncrystalline phases. A reduction of Ge-O species was observed in the superlattice during thermal annealing, accompanied by a transition from oxygen-deficient silicon oxide to silicon dioxide. A growth mechanism involving phase separation of Ge suboxides (GeOx was then proposed to explain these findings and supplement the existing growth models for Ge-ncs in SiO2 films. Further analysis of the bonding structure of Ge atoms suggested that Ge-ncs are likely to have a core-shell structure with an amorphous-like surface layer, which is composed of GeSiO ternary complex. The surface layer thickness was extracted to be a few angstroms and equivalent to several atomic layer thicknesses.

  12. Metastability and relaxation in tensile SiGe on Ge(001) virtual substrates

    International Nuclear Information System (INIS)

    Frigerio, Jacopo; Lodari, Mario; Chrastina, Daniel; Mondiali, Valeria; Isella, Giovanni; Bollani, Monica

    2014-01-01

    We systematically study the heteroepitaxy of SiGe alloys on Ge virtual substrates in order to understand strain relaxation processes and maximize the tensile strain in the SiGe layer. The degree of relaxation is measured by high-resolution x-ray diffraction, and surface morphology is characterized by atomic force microscopy. The results are analyzed in terms of a numerical model, which considers dislocation nucleation, multiplication, thermally activated glide, and strain-dependent blocking. Relaxation is found to be sensitive to growth rate and substrate temperature as well as epilayer misfit and thickness, and growth parameters are found which allow a SiGe film with over 4 GPa of tensile stress to be obtained.

  13. Comparative study of the luminescence of structures with Ge nanocrystals formed by dry and wet oxidation of SiGe films

    International Nuclear Information System (INIS)

    RodrIguez, A; Ortiz, M I; Sangrador, J; RodrIguez, T; Avella, M; Prieto, A C; Torres, A; Jimenez, J; Kling, A; Ballesteros, C

    2007-01-01

    The luminescence emission of structures containing Ge nanocrystals embedded in a dielectric matrix obtained by dry and wet oxidation of polycrystalline SiGe layers has been studied as a function of the oxidation time and initial SiGe layer thickness. A clear relationship between the intensity of the luminescence, the structure of the sample, the formation of Ge nanocrystals and the oxidation process parameters that allows us to select the appropriate process conditions to get the most efficient emission has been established. The evolution of the composition and thickness of the growing oxides and the remaining SiGe layer during the oxidation processes has been characterized using Raman spectroscopy, x-ray diffraction, Fourier-transform infrared spectroscopy, Rutherford backscattering spectrometry and transmission electron microscopy. For dry oxidation, the luminescence appears suddenly, regardless of the initial SiGe layer thickness, when all the Si of the SiGe has been oxidized and the remaining layer of the segregated Ge starts to be oxidized forming Ge nanocrystals. Luminescence is observed as long as Ge nanocrystals are present. For wet oxidation, the luminescence appears from the first stages of the oxidation, and is related to the formation of Ge-rich nanoclusters trapped in the mixed (Si and Ge) growing oxide. A sharp increase of the luminescence intensity for long oxidation times is also observed, due to the formation of Ge nanocrystals by the oxidation of the layer of segregated Ge. For both processes the luminescence is quenched when the oxidation time is long enough to cause the full oxidation of the Ge nanocrystals. The intensity of the luminescence in the dry oxidized samples is about ten times higher than in the wet oxidized ones for equal initial thickness of the SiGe layer

  14. Si/Ge intermixing during Ge Stranski–Krastanov growth

    Directory of Open Access Journals (Sweden)

    Alain Portavoce

    2014-12-01

    Full Text Available The Stranski–Krastanov growth of Ge islands on Si(001 has been widely studied. The morphology changes of Ge islands during growth, from nucleation to hut/island formation and growth, followed by hut-to-dome island transformation and dislocation nucleation of domes, have been well described, even at the atomic scale, using techniques such as scanning tunneling microscopy and transmission electron microscopy. Although it is known that these islands do not consist of pure Ge (due to Si/Ge intermixing, the composition of the Ge islands is not precisely known. In the present work, atom probe tomography was used to study the composition of buried dome islands at the atomic scale, in the three-dimensional space. The core of the island was shown to contain about 55 atom % Ge, while the Ge composition surrounding this core decreases rapidly in all directions in the islands to reach a Ge concentration of about 15 atom %. The Ge distribution in the islands follows a cylindrical symmetry and Ge segregation is observed only in the {113} facets of the islands. The Ge composition of the wetting layer is not homogeneous, varying from 5 to 30 atom %.

  15. Direct observation of a non-isothermal crystallization process in precursor Li10GeP2S12 glass electrolyte

    Science.gov (United States)

    Tsukasaki, Hirofumi; Mori, Shigeo; Shiotani, Shinya; Yamamura, Hideyuki; Iba, Hideki

    2017-11-01

    Crystallization of a precursor Li10GeP2S12 (LGPS) glass electrolyte by heat treatment significantly improves its ionic conductivity. The LGPS crystalline phase obtained by heat treatment above 450 °C shows an ionic conductivity on the order of 10-2 S/cm. To clarify the correlation between the crystallization behavior of precursor LGPS glasses and ionic conductivity, we developed an observation technique to visualize precipitated nanocrystallites and a new method to evaluate the crystallization degree via transmission electron microscopy (TEM). In-situ TEM observation revealed that LGPS nanocrystallites precipitated above 450 °C and their size remained fundamentally intact during heating. That is, the crystallization behavior could be characterized by only the formation of LGPS nanocrystallites in an amorphous matrix. In addition, the crystallization degree was quantitatively evaluated from electron diffraction patterns. The crystallization degree remarkably increased at around 450 °C and reached more than 60% above 450 °C. Based on these results, a high ionic conductivity of approximately 1.0 × 10-2 S/cm was confirmed to be directly associated with the appearance of the LGPS crystalline phase.

  16. Distribution and Substitution Mechanism of Ge in a Ge-(Fe-Bearing Sphalerite

    Directory of Open Access Journals (Sweden)

    Nigel J. Cook

    2015-03-01

    Full Text Available The distribution and substitution mechanism of Ge in the Ge-rich sphalerite from the Tres Marias Zn deposit, Mexico, was studied using a combination of techniques at μm- to atomic scales. Trace element mapping by Laser Ablation Inductively Coupled Mass Spectrometry shows that Ge is enriched in the same bands as Fe, and that Ge-rich sphalerite also contains measurable levels of several other minor elements, including As, Pb and Tl. Micron- to nanoscale heterogeneity in the sample, both textural and compositional, is revealed by investigation using Focused Ion Beam-Scanning Electron Microscopy (FIB-SEM combined with Synchrotron X-ray Fluorescence mapping and High-Resolution Transmission Electron Microscopy imaging of FIB-prepared samples. Results show that Ge is preferentially incorporated within Fe-rich sphalerite with textural complexity finer than that of the microbeam used for the X-ray Absorption Near Edge Structure (XANES measurements. Such heterogeneity, expressed as intergrowths between 3C sphalerite and 2H wurtzite on  zones, could be the result of either a primary growth process, or alternatively, polystage crystallization, in which early Fe-Ge-rich sphalerite is partially replaced by Fe-Ge-poor wurtzite. FIB-SEM imaging shows evidence for replacement supporting the latter. Transformation of sphalerite into wurtzite is promoted by (111* twinning or lattice-scale defects, leading to a heterogeneous ZnS sample, in which the dominant component, sphalerite, can host up to ~20% wurtzite. Ge K-edge XANES spectra for this sphalerite are identical to those of the germanite and argyrodite standards and the synthetic chalcogenide glasses GeS2 and GeSe2, indicating the Ge formally exists in the tetravalent form in this sphalerite. Fe K-edge XANES spectra for the same sample indicate that Fe is present mainly as Fe2+, and Cu K-edge XANES spectra are characteristic for Cu+. Since there is no evidence for coupled substitution involving a monovalent

  17. Stress evolution of Ge nanocrystals in dielectric matrices

    Science.gov (United States)

    Bahariqushchi, Rahim; Raciti, Rosario; Emre Kasapoğlu, Ahmet; Gür, Emre; Sezen, Meltem; Kalay, Eren; Mirabella, Salvatore; Aydinli, A.

    2018-05-01

    Germanium nanocrystals (Ge NCs) embedded in single and multilayer silicon oxide and silicon nitride matrices have been synthesized using plasma enhanced chemical vapor deposition followed by conventional furnace annealing or rapid thermal processing in N2 ambient. Compositions of the films were determined by Rutherford backscattering spectrometry and x-ray photoelectron spectroscopy. The formation of NCs under suitable process conditions was observed with high resolution transmission electron microscope micrographs and Raman spectroscopy. Stress measurements were done using Raman shifts of the Ge optical phonon line at 300.7 cm-1. The effect of the embedding matrix and annealing methods on Ge NC formation were investigated. In addition to Ge NCs in single layer samples, the stress on Ge NCs in multilayer samples was also analyzed. Multilayers of Ge NCs in a silicon nitride matrix separated by dielectric buffer layers to control the size and density of NCs were fabricated. Multilayers consisted of SiN y :Ge ultrathin films sandwiched between either SiO2 or Si3N4 by the proper choice of buffer material. We demonstrated that it is possible to tune the stress state of Ge NCs from compressive to tensile, a desirable property for optoelectronic applications. We also observed that there is a correlation between the stress and the crystallization threshold in which the compressive stress enhances the crystallization, while the tensile stress suppresses the process.

  18. Space charge sign inversion and electric field reconstruction in 24 GeV/c proton-irradiated MCZ Si p+-n(TD)-n+ detectors processed via thermal donor introduction

    International Nuclear Information System (INIS)

    Li, Z.; Verbitskaya, E.; Carini, G.; Chen, W.; Eremin, V.; Gul, R.; Haerkoenen, J.; Li, M.

    2009-01-01

    The aim of this study is the evaluation of radiation effects in detectors based on p-type magnetic czochralski (MCZ) Si that was converted to n-type by thermal donor (TD) introduction. As-processed p + -p-n + detectors were annealed at 430 deg. C resulting in p + -n(TD)-n + structures. The space charge sign and the electric field distribution E(x) in MCz Si p + -n(TD)-n + detectors irradiated by 24 GeV/c protons were analyzed using the data on the current pulse response and the Double Peak (DP) electric field distribution model for heavily irradiated detectors. The approach considers an irradiated detector as a structure with three regions in which the electric field depends on the coordinate, and the induced current pulse response arises from the drift process of free carriers in the detector with variable electric field. Reconstruction of the E(x) profile from the pulse response shapes is performed employing a new method for DP electric field reconstruction. This method includes: (a) a direct extraction of charge loss due to trapping and (b) the fitting of a simulated pulse response to the 'corrected' pulse by adjusting the electric field profiles in the three regions. Reconstruction of E(x) distribution showed that in the diodes irradiated by a proton fluence of (2-4)x10 14 p/cm 2 space charge sign inversion has occurred. This is the evidence that the influence of 24 GeV/c proton radiation on MCz Si p + -n(TD)-n + detectors is similar to that on p + -n-n + detectors based on FZ or diffusion oxygenated n-type Si.

  19. Ion beam analysis of the dry thermal oxidation of thin polycrystalline SiGe films

    International Nuclear Information System (INIS)

    Kling, A.; Soares, J.C.; Prieto, A.C.; Jimenez, J.; Rodriguez, A.; Sangrador, J.; Rodriguez, T.

    2005-01-01

    Nanoparticles of Ge embedded in a formed dielectric matrix appear as very promising systems for electronic and photonic applications. We present here an exhaustive characterization of the oxidation process of polycrystalline SiGe layers from the starting of its oxidation process to the total oxidation of it. We have characterized the process by RBS, FTIR and Raman spectroscopy, showing the necessity to use different techniques in order to get a full view of the process. First the Si-Si and Si-Ge bonds are oxidized growing SiO 2 , and Ge segregates from the SiO 2 . As soon as all Si is oxidized GeO 2 is growing gradually. RBS has demonstrated to be very useful to characterize the SiO 2 and the remaining non-oxidized poly-SiGe layer thickness, as well as for the determination of the Ge fraction, where the high sensitivity of this technique allows to explore its whole range. On the other hand, for the reliable determination of the GeO 2 thickness, information on the amount of Ge-O bonding had to be obtained from FTIR spectra. Raman spectroscopy yields detailed information about the oxidation processes for different bonds (Si-Si, Si-Ge, Ge-Ge)

  20. Investigation of electrochemical reduction of GeO2 to Ge in molten CaCl2-NaCl

    International Nuclear Information System (INIS)

    Rong, Liangbin; He, Rui; Wang, Zhiyong; Peng, Junjun; Jin, Xianbo; Chen, George Z.

    2014-01-01

    Electrochemical reduction of solid GeO 2 has been investigated in the mixed CaCl 2 -NaCl melt at 1023 K for developing a more efficient process for preparation of Ge. Cyclic voltammetry and potentiostatic electrolysis were applied to study the GeO 2 -loaded metallic cavity electrode. In addition, porous GeO 2 pellets were reduced by potentiostatic and constant cell voltage electrolysis with a graphite anode, and the electrolysis products were analyzed by powder X-ray diffraction, scanning electron microscopy and energy-dispersive X-ray spectrometry, focusing on understanding the reduction mechanism and the impact of electrode potential on the product purity. It was found that the reduction of GeO 2 to Ge occurred at a potential of about -0.50 V (vs. Ag/Ag + ), but generating various calcium germanates simultaneously, whose reduction was a little more difficult and needed a potential more negative than -1.00 V. However, if the cathode potential exceeded -1.60 V, Ca (or Na) - Ge intermetallic compounds might form. These results gave an appropriate potential range between -1.10 and -1.40 V for the production of pure germanium. Rapid electrolysis of GeO 2 to pure Ge has been realized at a cell voltage of 2.5 V with a current efficiency of about 92%

  1. Cross sections of production of J / {psi}, {psi}` resonances and of the Drell-Yan process in the Pb-Pb interactions with 158 GeV / c per nucleon; Section efficaces de production des resonances J / {psi}, {psi}` et du processus Drell-Yan dans les interactions Pb-Pb a 158 GeV / c par nucleon

    Energy Technology Data Exchange (ETDEWEB)

    Bellaiche, F

    1997-04-24

    In the framework of the experimental research for the quark and gluons plasma formation in ultrarelativistic heavy ion collisions, data obtained by the NA50 collaboration at SPS-CERN are analysed. The segmented target used by NA50 experiment is described and analysed in terms of vertex identification efficiency and re-interactions recognition. The absolute J/{psi}, {psi}`and Drell-Yan process cross-sections in 158 GeV/c per nucleon Pb-Pb interactions are extracted. The transverse energy dependence of the production yield of J/{psi} and Drell-Yan process is established. The comparison of these cross-sections with the ones measured in lighter systems and the comparison of the E dependence of J/{psi} production with the Glauber model prediction show an anomalous J/{psi} suppression observed in Pb-Pb interactions is confronted to theoretical models proposed by several authors, describing charmonium bound states formation and interactions is confronted to theoretical models proposed by several authors, describing charmonium bound states formation and interactions in confined or deconfined media. (author) 122 refs.

  2. Kinetics of plasma oxidation of germanium-tin (GeSn)

    Science.gov (United States)

    Wang, Wei; Lei, Dian; Dong, Yuan; Zhang, Zheng; Pan, Jisheng; Gong, Xiao; Tok, Eng-Soon; Yeo, Yee-Chia

    2017-12-01

    The kinetics of plasma oxidation of GeSn at low temperature is investigated. The oxidation process is described by a power-law model where the oxidation rate decreases rapidly from the initial oxidation rate with increasing time. The oxidation rate of GeSn is higher than that of pure Ge, which can be explained by the higher chemical reaction rate at the GeSn-oxide/GeSn interface. In addition, the Sn atoms at the interface region exchange positions with the underlying Ge atoms during oxidation, leading to a SnO2-rich oxide near the interface. The bandgap of GeSn oxide is extracted to be 5.1 ± 0.2 eV by XPS, and the valence band offset at the GeSn-oxide/GeSn heterojunction is found to be 3.7 ± 0.2 eV. Controlled annealing experiments demonstrate that the GeSn oxide is stable with respect to annealing temperatures up to 400 °C. However, after annealing at 450 °C, the GeO2 is converted to GeO, and desorbs from the GeSn-oxide/GeSn, leaving behind Sn oxide.

  3. Inhibitive formation of nanocavities by introduction of Si atoms in Ge nanocrystals produced by ion implantation

    Energy Technology Data Exchange (ETDEWEB)

    Cai, R. S.; Shang, L.; Liu, X. H.; Zhang, Y. J. [The Cultivation Base for State Key Laboratory, Qingdao University, No. 308 Ningxia Road, Qingdao 266071 (China); Wang, Y. Q., E-mail: yqwang@qdu.edu.cn, E-mail: barba@emt.inrs.ca [The Cultivation Base for State Key Laboratory, Qingdao University, No. 308 Ningxia Road, Qingdao 266071 (China); College of Physics Science, Qingdao University, No. 308 Ningxia Road, Qingdao 266071 (China); Ross, G. G.; Barba, D., E-mail: yqwang@qdu.edu.cn, E-mail: barba@emt.inrs.ca [INRS-Énergie, Matériaux et Télécommunications, 1650 boulevard Lionel-Boulet, Varennes Québec J3X 1S2 (Canada)

    2014-05-28

    Germanium nanocrystals (Ge-nc) were successfully synthesized by co-implantation of Si and Ge ions into a SiO{sub 2} film thermally grown on (100) Si substrate and fused silica (pure SiO{sub 2}), respectively, followed by subsequent annealing at 1150 °C for 1 h. Transmission electron microscopy (TEM) examinations show that nanocavities only exist in the fused silica sample but not in the SiO{sub 2} film on a Si substrate. From the analysis of the high-resolution TEM images and electron energy-loss spectroscopy spectra, it is revealed that the absence of nanocavities in the SiO{sub 2} film/Si substrate is attributed to the presence of Si atoms inside the formed Ge-nc. Because the energy of Si-Ge bonds (301 kJ·mol{sup −1}) are greater than that of Ge-Ge bonds (264 kJ·mol{sup −1}), the introduction of the Si-Ge bonds inside the Ge-nc can inhibit the diffusion of Ge from the Ge-nc during the annealing process. However, for the fused silica sample, no crystalline Si-Ge bonds are detected within the Ge-nc, where strong Ge outdiffusion effects produce a great number of nanocavities. Our results can shed light on the formation mechanism of nanocavities and provide a good way to avoid nanocavities during the process of ion implantation.

  4. PECVD Tekniği ile Büyütülmüş İnce Filmlerde Oluşan Ge ve SiGe Nanokristallerin Geçirgen Elektron Mikroskobu (TEM) ,Raman ve Fotoışıma Spektroskopisi Teknikleri ile İncelenmesi

    OpenAIRE

    Şahin, Bünyamin; Ağan, Sedat

    2009-01-01

    We report an experimental study, optical properties of Ge and SiGe nanocrystals in SiOx structures are investigated by using Transmission Electron Microscopy (TEM), Raman and Photlüminescence Spectroscopy techniques. Ge nanocrystals in silicon oxide thin films have been grown with different annealing time by Plasma Enhanced Chemical Vapor Deposition (PECVD) technique. The aim of our work is to determine size and size distiributions Ge, SiGe nanocrystals in SiOx martix due to annealing process...

  5. Fabrication of prototypes of Ge(li) semiconductor detector

    International Nuclear Information System (INIS)

    Santos, W.M.S.; Marti, G.V.; Rizzo, P.; Barros, S. de.

    1987-01-01

    The fabrication process of Ge(Li) semiconductor detector prototypes, from specific chemical treatments of doped monocrystal with receptor impurities (p + semicondutor) is presented. The detector characteristics, such as resulotion and operation tension are shown. (M.C.K.) [pt

  6. Ge/SiGe superlattices for nanostructured thermoelectric modules

    International Nuclear Information System (INIS)

    Chrastina, D.; Cecchi, S.; Hague, J.P.; Frigerio, J.; Samarelli, A.; Ferre–Llin, L.; Paul, D.J.; Müller, E.; Etzelstorfer, T.; Stangl, J.; Isella, G.

    2013-01-01

    Thermoelectrics are presently used in a number of applications for both turning heat into electricity and also for using electricity to produce cooling. Mature Si/SiGe and Ge/SiGe heteroepitaxial growth technology would allow highly efficient thermoelectric materials to be engineered, which would be compatible and integrable with complementary metal oxide silicon micropower circuits used in autonomous systems. A high thermoelectric figure of merit requires that electrical conductivity be maintained while thermal conductivity is reduced; thermoelectric figures of merit can be improved with respect to bulk thermoelectric materials by fabricating low-dimensional structures which enhance the density of states near the Fermi level and through phonon scattering at heterointerfaces. We have grown and characterized Ge-rich Ge/SiGe/Si superlattices for nanofabricated thermoelectric generators. Low-energy plasma-enhanced chemical vapor deposition has been used to obtain nanoscale-heterostructured material which is several microns thick. Crystal quality and strain control have been investigated by means of high resolution X-ray diffraction. High-resolution transmission electron microscopy images confirm the material and interface quality. Electrical conductivity has been characterized by the mobility spectrum technique. - Highlights: ► High-quality Ge/SiGe multiple quantum wells for thermoelectric applications ► Mobility spectra of systems featuring a large number of parallel conduction channels ► Competitive thermoelectric properties measured in single devices

  7. Improving the electrode performance of Ge through Ge@C core-shell nanoparticles and graphene networks.

    Science.gov (United States)

    Xue, Ding-Jiang; Xin, Sen; Yan, Yang; Jiang, Ke-Cheng; Yin, Ya-Xia; Guo, Yu-Guo; Wan, Li-Jun

    2012-02-08

    Germanium is a promising high-capacity anode material for lithium ion batteries, but it usually exhibits poor cycling stability because of its huge volume variation during the lithium uptake and release process. A double protection strategy to improve the electrode performance of Ge through the use of Ge@C core-shell nanostructures and reduced graphene oxide (RGO) networks has been developed. The as-synthesized Ge@C/RGO nanocomposite showed excellent cycling performance and rate capability in comparison with Ge@C nanoparticles when used as an anode material for Li ion batteries, which can be attributed to the electronically conductive and elastic RGO networks in addition to the carbon shells and small particle sizes of Ge. The strategy is simple yet very effective, and because of its versatility, it may be extended to other high-capacity electrode materials with large volume variations and low electrical conductivities.

  8. Structure of 78Ge from the 76Ge(t,p)78Ge reaction

    International Nuclear Information System (INIS)

    Ardouin, D.; Lebrun, C.; Guilbault, F.; Remaud, B.; Vergnes, M.N.; Rotbard, G.; Kumar, K.

    1978-01-01

    The 76 Ge(t,p) 78 Ge reaction has been performed at a bombarding energy of 17 MeV. Thirteen excited states below 3 MeV excitation are reported with Jsup(π) values obtained by comparison to DWBA analysis. A comparison to a dynamical deformation theory is made and the results suggest 78 Ge is a transitional nucleus nearing spherical shape due to the proximity of the N-50 closed shell

  9. Photoluminescence and electroluminescence from Ge/strained GeSn/Ge quantum wells

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Chung-Yi; Chang, Chih-Chiang [Department of Electrical Engineering, Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei 10617, Taiwan (China); Huang, Chih-Hsiung; Huang, Shih-Hsien [Department of Electrical Engineering, Graduate Institute of Electronics Engineering, National Taiwan University, Taipei 10617, Taiwan (China); Liu, C. W., E-mail: chee@cc.ee.ntu.edu.tw [Department of Electrical Engineering, Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei 10617, Taiwan (China); Department of Electrical Engineering, Graduate Institute of Electronics Engineering, National Taiwan University, Taipei 10617, Taiwan (China); National Nano Device Labs, Hsinchu 30077, Taiwan (China); Huang, Yi-Chiau; Chung, Hua; Chang, Chorng-Ping [Applied Materials Inc., Sunnyvale, California 94085 (United States)

    2016-08-29

    Ge/strained GeSn/Ge quantum wells are grown on a 300 mm Si substrate by chemical vapor deposition. The direct bandgap emission from strained GeSn is observed in the photoluminescence spectra and is enhanced by Al{sub 2}O{sub 3}/SiO{sub 2} passivation due to the field effect. The electroluminescence of the direct bandgap emission of strained GeSn is also observed from the Ni/Al{sub 2}O{sub 3}/GeSn metal-insulator-semiconductor tunneling diodes. Electroluminescence is a good indicator of GeSn material quality, since defects in GeSn layers degrade the electroluminescence intensity significantly. At the accumulation bias, the holes in the Ni gate electrode tunnel to the strained n-type GeSn layer through the ultrathin Al{sub 2}O{sub 3} and recombine radiatively with electrons. The emission wavelength of photoluminescence and electroluminescence can be tuned by the Sn content.

  10. 75 FR 47318 - GE Asset Management Incorporated and GE Investment Distributors, Inc.; Notice of Application and...

    Science.gov (United States)

    2010-08-05

    ...] GE Asset Management Incorporated and GE Investment Distributors, Inc.; Notice of Application and.... Applicants: GE Asset Management Incorporated (``GEAM'') and GE Investment Distributors, Inc. (``GEID... of Investment Management, Office of Investment Company Regulation). SUPPLEMENTARY INFORMATION: The...

  11. Study of the quasi-two body processes including Σ(1385) production in π-p and K-p reactions at 4 GeV/c

    International Nuclear Information System (INIS)

    Aguilar-Benitez, M.; Salicio, J.

    1981-01-01

    An analysis of (1385) production in reactions of the type 0 + 1/z 4 +→>-1 + 3+/2 and 0 - + 1/2+→ 0 - + 3*/2 is presented. A determination of the Σ(1385) production parameters Is performed and the results are compared with the predictions from several models. A transversity amplitudes reconstruction describing the processes π p ->K(890) Σ(1385) and K - p → 3→φ(1385), ζ - Σ(1385) is obtained in a model independent way. We observe dominance of unnatural partly exchange in the production mechanisms. Exchanges of exotic quantum numbers are established by the study of πp → K 0 + Σ(1385)s and K - p→>π+Σ(1385)± processes. Additive quark model predictions are reasonable agreement with the experimental data. (Author)

  12. Density functional study of the decomposition pathways of SiH₃ and GeH₃ at the Si(100) and Ge(100) surfaces.

    Science.gov (United States)

    Ceriotti, M; Montalenti, F; Bernasconi, M

    2012-03-14

    By means of first-principles calculations we studied the decomposition pathways of SiH₃ on Ge(100) and of GeH₃ on Si(100), of interest for the growth of crystalline SiGe alloys and Si/Ge heterostructures by plasma-enhanced chemical vapor deposition. We also investigated H desorption via reaction of two adsorbed SiH₂/GeH₂ species (β₂ reaction) or via Eley-Rideal abstraction of surface H atoms from the impinging SiH₃ and GeH₃ species. The calculated activation energies for the different processes suggest that the rate-limiting step for the growth of Si/Ge systems is still the β₂ reaction of two SiH₂ as in the growth of crystalline Si.

  13. Applications of Si/SiGe heterostructures to CMOS devices

    International Nuclear Information System (INIS)

    Sidek, R.M.

    1999-03-01

    For more than two decades, advances in MOSFETs used in CMOS VLSI applications have been made through scaling to ever smaller dimensions for higher packing density, faster circuit speed and lower power dissipation. As scaling now approaches nanometer regime, the challenge for further scaling becomes greater in terms of technology as well as device reliability. This work presents an alternative approach whereby non-selectively grown Si/SiGe heterostructure system is used to improve device performance or to relax the technological challenge. SiGe is considered to be of great potential because of its promising properties and its compatibility with Si, the present mainstream material in microelectronics. The advantages of introducing strained SiGe in CMOS technology are examined through two types of device structure. A novel structure has been fabricated in which strained SiGe is incorporated in the source/drain of P-MOSFETs. Several advantages of the Si/SiGe source/drain P-MOSFETs over Si devices are experimentally, demonstrated for the first time. These include reduction in off-state leakage and punchthrough susceptibility, degradation of parasitic bipolar transistor (PBT) action, suppression of CMOS latchup and suppression of PBT-induced breakdown. The improvements due to the Si/SiGe heterojunction are supported by numerical simulations. The second device structure makes use of Si/SiGe heterostructure as a buried channel to enhance the hole mobility of P-MOSFETs. The increase in the hole mobility will benefit the circuit speed and device packing density. Novel fabrication processes have been developed to integrate non-selective Si/SiGe MBE layers into self-aligned PMOS and CMOS processes based on Si substrate. Low temperature processes have been employed including the use of low-pressure chemical vapor deposition oxide and plasma anodic oxide. Low field mobilities, μ 0 are extracted from the transfer characteristics, Id-Vg of SiGe channel P-MOSFETs with various Ge

  14. Measurement of the Cross-Section for the Process $\\gamma-\\gamma$ to Proton-Antiproton at $\\sqrt{s_{ee}}$ = 183 - 189 GeV with the OPAL Detector at LEP

    CERN Document Server

    Barillari, T

    2004-01-01

    The exclusive production of proton-antiproton pairs in the collisions of two quasi-real photons has been studied using data taken at sqrt(s_ee) = 183 GeV and 189 GeV with the OPAL detector at LEP. Results are presented for proton-antiproton invariant masses, W, in the range 2.15 < W < 3.95 GeV. The cross-section measurements are compared with previous data and with recent analytic calculations based on the quark-diquark model.

  15. Measurement of the Cross-Section for the Process $\\gamma\\gamma \\to p \\overline{p}$ at $\\sqrt{s}_{ee}$=183-189 GeV at LEP

    CERN Document Server

    Abbiendi, G.; Akesson, P.F.; Alexander, G.; Allison, John; Amaral, P.; Anagnostou, G.; Anderson, K.J.; Arcelli, S.; Asai, S.; Axen, D.; Azuelos, G.; Bailey, I.; Barberio, E.; Barillari, T.; Barlow, R.J.; Batley, R.J.; Bechtle, P.; Behnke, T.; Bell, Kenneth Watson; Bell, P.J.; Bella, G.; Bellerive, A.; Benelli, G.; Bethke, S.; Biebel, O.; Bloodworth, I.J.; Boeriu, O.; Bock, P.; Bonacorsi, D.; Boutemeur, M.; Braibant, S.; Brigliadori, L.; Brown, Robert M.; Buesser, K.; Burckhart, H.J.; Campana, S.; Carnegie, R.K.; Caron, B.; Carter, A.A.; Carter, J.R.; Chang, C.Y.; Charlton, David G.; Csilling, A.; Cuffiani, M.; Dado, S.; Dallavalle, G.Marco; Dallison, S.; De Roeck, A.; De Wolf, E.A.; Desch, K.; Dienes, B.; Donkers, M.; Dubbert, J.; Duchovni, E.; Duckeck, G.; Duerdoth, I.P.; Elfgren, E.; Etzion, E.; Fabbri, F.; Feld, L.; Ferrari, P.; Fiedler, F.; Fleck, I.; Ford, M.; Frey, A.; Furtjes, A.; Gagnon, P.; Gary, John William; Gaycken, G.; Geich-Gimbel, C.; Giacomelli, G.; Giacomelli, P.; Giunta, Marina; Goldberg, J.; Gross, E.; Grunhaus, J.; Gruwe, M.; Gunther, P.O.; Gupta, A.; Hajdu, C.; Hamann, M.; Hanson, G.G.; Harder, K.; Harel, A.; Harin-Dirac, M.; Hauschild, M.; Hauschildt, J.; Hawkes, C.M.; Hawkings, R.; Hemingway, R.J.; Hensel, C.; Herten, G.; Heuer, R.D.; Hill, J.C.; Hoffman, Kara Dion; Homer, R.J.; Horvath, D.; Howard, R.; Huntemeyer, P.; Igo-Kemenes, P.; Ishii, K.; Jeremie, H.; Jovanovic, P.; Junk, T.R.; Kanaya, N.; Kanzaki, J.; Karapetian, G.; Karlen, D.; Kartvelishvili, V.; Kawagoe, K.; Kawamoto, T.; Keeler, R.K.; Kellogg, R.G.; Kennedy, B.W.; Kim, D.H.; Klein, K.; Klier, A.; Kluth, S.; Kobayashi, T.; Kobel, M.; Komamiya, S.; Kormos, Laura L.; Kowalewski, Robert V.; Kramer, T.; Kress, T.; Krieger, P.; von Krogh, J.; Krop, D.; Kruger, K.; Kupper, M.; Lafferty, G.D.; Landsman, H.; Lanske, D.; Layter, J.G.; Leins, A.; Lellouch, D.; Letts, J.; Levinson, L.; Lillich, J.; Lloyd, S.L.; Loebinger, F.K.; Lu, J.; Ludwig, J.; Macpherson, A.; Mader, W.; Marcellini, S.; Marchant, T.E.; Martin, A.J.; Martin, J.P.; Masetti, G.; Mashimo, T.; Mattig, Peter; McDonald, W.J.; McKenna, J.; McMahon, T.J.; McPherson, R.A.; Meijers, F.; Mendez-Lorenzo, P.; Menges, W.; Merritt, F.S.; Mes, H.; Michelini, A.; Mihara, S.; Mikenberg, G.; Miller, D.J.; Moed, S.; Mohr, W.; Mori, T.; Mutter, A.; Nagai, K.; Nakamura, I.; Neal, H.A.; Nisius, R.; O'Neale, S.W.; Oh, A.; Okpara, A.; Oreglia, M.J.; Orito, S.; Pahl, C.; Pasztor, G.; Pater, J.R.; Patrick, G.N.; Pilcher, J.E.; Pinfold, J.; Plane, David E.; Poli, B.; Polok, J.; Pooth, O.; Przybycien, M.; Quadt, A.; Rabbertz, K.; Rembser, C.; Renkel, P.; Rick, H.; Roney, J.M.; Rosati, S.; Rozen, Y.; Runge, K.; Sachs, K.; Saeki, T.; Sahr, O.; Sarkisyan, E.K.G.; Schaile, A.D.; Schaile, O.; Scharff-Hansen, P.; Schieck, J.; Schoerner-Sadenius, Thomas; Schroder, Matthias; Schumacher, M.; Schwick, C.; Scott, W.G.; Seuster, R.; Shears, T.G.; Shen, B.C.; Shepherd-Themistocleous, C.H.; Sherwood, P.; Siroli, G.; Skuja, A.; Smith, A.M.; Sobie, R.; Soldner-Rembold, S.; Spagnolo, S.; Spano, F.; Stahl, A.; Stephens, K.; Strom, David M.; Strohmer, R.; Tarem, S.; Tasevsky, M.; Taylor, R.J.; Teuscher, R.; Thomson, M.A.; Torrence, E.; Toya, D.; Tran, P.; Trefzger, T.; Tricoli, A.; Trigger, I.; Trocsanyi, Z.; Tsur, E.; Turner-Watson, M.F.; Ueda, I.; Ujvari, B.; Vachon, B.; Vollmer, C.F.; Vannerem, P.; Verzocchi, M.; Voss, H.; Vossebeld, J.; Waller, D.; Ward, C.P.; Ward, D.R.; Watkins, P.M.; Watson, A.T.; Watson, N.K.; Wells, P.S.; Wengler, T.; Wermes, N.; Wetterling, D.; Wilson, G.W.; Wilson, J.A.; Wolf, G.; Wyatt, T.R.; Yamashita, S.; Zer-Zion, D.; Zivkovic, Lidija

    2003-01-01

    The exclusive production of proton-antiproton pairs in the collisions of two quasi-real photons had been studied using data taken at sqrt(s)_ee=183 GeV and 189 GeV with the OPAL detector at LEP. Results are presented for Ppbar invariant masses, W, in the range 2.15 W< <3.95 GeV. The cross-section measurements are compared with previous data and with recent analytic calculations based on the quark-diquark model.

  16. Ge-Au eutectic bonding of Ge (100) single crystals

    International Nuclear Information System (INIS)

    Knowlton, W.B.; Beeman, J.W.; Emes, J.H.; Loretto, D.; Itoh, K.M.; Haller, E.E.

    1993-01-01

    The author present preliminary results on the eutectic bonding between two (100) Ge single crystal surfaces using thin films of Au ranging from 900 angstrom/surface to 300 angstrom/surface and Pd (10% the thickness of Au). Following bonding, plan view optical microscopy (OM) of the cleaved interface of samples with Au thicknesses ≤ 500 angstrom/surface show a eutectic morphology more conducive to phonon transmission through the bond interface. High resolution transmission electron microscopy (HRTEM) cross sectional interface studies of a 300 angstrom/surface Au sample show epitaxial growth of Ge. In sections of the bond, lattice continuity of the Ge is apparent through the interface. TEM studies also reveal heteroepitaxial growth of Au with a Au-Ge lattice mismatch of less than 2%. Eutectic bonds with 200 angstrom/surface Au have been attained with characterization pending. An optical polishing technique for Ge has been optimized to insure intimate contact between the Ge surfaces prior to bonding. Interferometry analysis of the optically polished Ge surface shows that surface height fluctuations lie within ±150 angstrom across an interval of lmm. Characterization of phonon transmission through the interface is discussed with respect to low temperature detection of ballistic phonons

  17. Si, Ge and SiGe wires for sensor application

    International Nuclear Information System (INIS)

    Druzhinin, A.A.; Khoverko, Yu.M.; Ostrovskii, I.P.; Nichkalo, S.I.; Nikolaeva, A.A.; Konopko, L.A.; Stich, I.

    2011-01-01

    Resistance and magnetoresistance of Si, Ge and Si-Ge micro- and nanowires were studied in temperature range 4,2-300 K at magnetic fields up to 14 T. The wires diameters range from 200 nm to 20 μm. Ga-In gates were created to wires and ohmic I-U characteristics were observed in all temperature range. It was found high elastic strain for Ge nanowires (of about 0,7%) as well as high magnitude of magnetoresistance (of about 250% at 14 T), which was used to design multifunctional sensor of simultaneous measurements of strain and magnetic field intensity. (authors)

  18. Amorphous Ge quantum dots embedded in SiO2 formed by low energy ion implantation

    International Nuclear Information System (INIS)

    Zhao, J. P.; Huang, D. X.; Jacobson, A. J.; Chen, Z. Y.; Makarenkov, B.; Chu, W. K.; Bahrim, B.; Rabalais, J. W.

    2008-01-01

    Under ultrahigh vacuum conditions, extremely small Ge nanodots embedded in SiO 2 , i.e., Ge-SiO 2 quantum dot composites, have been formed by ion implantation of 74 Ge + isotope into (0001) Z-cut quartz at a low kinetic energy of 9 keV using varying implantation temperatures. Transmission electron microscopy (TEM) images and micro-Raman scattering show that amorphous Ge nanodots are formed at all temperatures. The formation of amorphous Ge nanodots is different from reported crystalline Ge nanodot formation by high energy ion implantation followed by a necessary high temperature annealing process. At room temperature, a confined spatial distribution of the amorphous Ge nanodots can be obtained. Ge inward diffusion was found to be significantly enhanced by a synergetic effect of high implantation temperature and preferential sputtering of surface oxygen, which induced a much wider and deeper Ge nanodot distribution at elevated implantation temperature. The bimodal size distribution that is often observed in high energy implantation was not observed in the present study. Cross-sectional TEM observation and the depth profile of Ge atoms in SiO 2 obtained from x-ray photoelectron spectra revealed a critical Ge concentration for observable amorphous nanodot formation. The mechanism of formation of amorphous Ge nanodots and the change in spatial distribution with implantation temperature are discussed

  19. Properties of slow traps of ALD Al{sub 2}O{sub 3}/GeO{sub x}/Ge nMOSFETs with plasma post oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Ke, M., E-mail: kiramn@mosfet.t.u-tokyo.ac.jp; Yu, X.; Chang, C.; Takenaka, M.; Takagi, S. [Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan and JST-CREST, K' s Gobancho 6F, 7 Gobancho, Chiyoda-ku, Tokyo 102-0076 (Japan)

    2016-07-18

    The realization of Ge gate stacks with a small amount of slow trap density as well as thin equivalent oxide thickness and low interface state density (D{sub it}) is a crucial issue for Ge CMOS. In this study, we examine the properties of slow traps, particularly the location of slow traps, of Al{sub 2}O{sub 3}/GeO{sub x}/n-Ge and HfO{sub 2}/Al{sub 2}O{sub 3}/GeO{sub x}/n-Ge MOS interfaces with changing the process and structural parameters, formed by atomic layer deposition (ALD) of Al{sub 2}O{sub 3} and HfO{sub 2}/Al{sub 2}O{sub 3} combined with plasma post oxidation. It is found that the slow traps can locate in the GeO{sub x} interfacial layer, not in the ALD Al{sub 2}O{sub 3} layer. Furthermore, we study the time dependence of channel currents in the Ge n-MOSFETs with 5-nm-thick Al{sub 2}O{sub 3}/GeO{sub x}/Ge gate stacks, with changing the thickness of GeO{sub x}, in order to further clarify the position of slow traps. The time dependence of the current drift and the effective time constant of slow traps do not change among the MOSFETs with the different thickness GeO{sub x}, demonstrating that the slow traps mainly exist near the interfaces between Ge and GeO{sub x}.

  20. Photoluminescence of phosphorus atomic layer doped Ge grown on Si

    Science.gov (United States)

    Yamamoto, Yuji; Nien, Li-Wei; Capellini, Giovanni; Virgilio, Michele; Costina, Ioan; Schubert, Markus Andreas; Seifert, Winfried; Srinivasan, Ashwyn; Loo, Roger; Scappucci, Giordano; Sabbagh, Diego; Hesse, Anne; Murota, Junichi; Schroeder, Thomas; Tillack, Bernd

    2017-10-01

    Improvement of the photoluminescence (PL) of Phosphorus (P) doped Ge by P atomic layer doping (ALD) is investigated. Fifty P delta layers of 8 × 1013 cm-2 separated by 4 nm Ge spacer are selectively deposited at 300 °C on a 700 nm thick P-doped Ge buffer layer of 1.4 × 1019 cm-3 on SiO2 structured Si (100) substrate. A high P concentration region of 1.6 × 1020 cm-3 with abrupt P delta profiles is formed by the P-ALD process. Compared to the P-doped Ge buffer layer, a reduced PL intensity is observed, which might be caused by a higher density of point defects in the P delta doped Ge layer. The peak position is shifted by ˜0.1 eV towards lower energy, indicating an increased active carrier concentration in the P-delta doped Ge layer. By introducing annealing at 400 °C to 500 °C after each Ge spacer deposition, P desorption and diffusion is observed resulting in relatively uniform P profiles of ˜2 × 1019 cm-3. Increased PL intensity and red shift of the PL peak are observed due to improved crystallinity and higher active P concentration.

  1. Monolithically Integrated Ge-on-Si Active Photonics

    Directory of Open Access Journals (Sweden)

    Jifeng Liu

    2014-07-01

    Full Text Available Monolithically integrated, active photonic devices on Si are key components in Si-based large-scale electronic-photonic integration for future generations of high-performance, low-power computation and communication systems. Ge has become an interesting candidate for active photonic devices in Si photonics due to its pseudo-direct gap behavior and compatibility with Si complementary metal oxide semiconductor (CMOS processing. In this paper, we present a review of the recent progress in Ge-on-Si active photonics materials and devices for photon detection, modulation, and generation. We first discuss the band engineering of Ge using tensile strain, n-type doping, Sn alloying, and separate confinement of Γ vs. L electrons in quantum well (QW structures to transform the material towards a direct band gap semiconductor for enhancing optoelectronic properties. We then give a brief overview of epitaxial Ge-on-Si materials growth, followed by a summary of recent investigations towards low-temperature, direct growth of high crystallinity Ge and GeSn alloys on dielectric layers for 3D photonic integration. Finally, we review the most recent studies on waveguide-integrated Ge-on-Si photodetectors (PDs, electroabsorption modulators (EAMs, and laser diodes (LDs, and suggest possible future research directions for large-scale monolithic electronic-photonic integrated circuits on a Si platform.

  2. Growth and evolution of nickel germanide nanostructures on Ge(001).

    Science.gov (United States)

    Grzela, T; Capellini, G; Koczorowski, W; Schubert, M A; Czajka, R; Curson, N J; Heidmann, I; Schmidt, Th; Falta, J; Schroeder, T

    2015-09-25

    Nickel germanide is deemed an excellent material system for low resistance contact formation for future Ge device modules integrated into mainstream, Si-based integrated circuit technologies. In this study, we present a multi-technique experimental study on the formation processes of nickel germanides on Ge(001). We demonstrate that room temperature deposition of ∼1 nm of Ni on Ge(001) is realized in the Volmer-Weber growth mode. Subsequent thermal annealing results first in the formation of a continuous NixGey wetting layer featuring well-defined terrace morphology. Upon increasing the annealing temperature to 300 °C, we observed the onset of a de-wetting process, characterized by the appearance of voids on the NixGey terraces. Annealing above 300 °C enhances this de-wetting process and the surface evolves gradually towards the formation of well-ordered, rectangular NixGey 3D nanostructures. Annealing up to 500 °C induces an Ostwald ripening phenomenon, with smaller nanoislands disappearing and larger ones increasing their size. Subsequent annealing to higher temperatures drives the Ni-germanide diffusion into the bulk and the consequent formation of highly ordered, {111} faceted Ni-Ge nanocrystals featuring an epitaxial relationship with the substrate Ni-Ge (101); (010) || Ge(001); (110).

  3. Analysis of threshold current of uniaxially tensile stressed bulk Ge and Ge/SiGe quantum well lasers.

    Science.gov (United States)

    Jiang, Jialin; Sun, Junqiang; Gao, Jianfeng; Zhang, Ruiwen

    2017-10-30

    We propose and design uniaxially tensile stressed bulk Ge and Ge/SiGe quantum well lasers with the stress along direction. The micro-bridge structure is adapted for introducing uniaxial stress in Ge/SiGe quantum well. To enhance the fabrication tolerance, full-etched circular gratings with high reflectivity bandwidths of ~500 nm are deployed in laser cavities. We compare and analyze the density of state, the number of states between Γ- and L-points, the carrier injection efficiency, and the threshold current density for the uniaxially tensile stressed bulk Ge and Ge/SiGe quantum well lasers. Simulation results show that the threshold current density of the Ge/SiGe quantum well laser is much higher than that of the bulk Ge laser, even combined with high uniaxial tensile stress owing to the larger number of states between Γ- and L- points and extremely low carrier injection efficiency. Electrical transport simulation reveals that the reduced effective mass of the hole and the small conduction band offset cause the low carrier injection efficiency of the Ge/SiGe quantum well laser. Our theoretical results imply that unlike III-V material, uniaxially tensile stressed bulk Ge outperforms a Ge/SiGe quantum well with the same strain level and is a promising approach for Si-compatible light sources.

  4. Ge/graded-SiGe multiplication layers for low-voltage and low-noise Ge avalanche photodiodes on Si

    Science.gov (United States)

    Miyasaka, Yuji; Hiraki, Tatsurou; Okazaki, Kota; Takeda, Kotaro; Tsuchizawa, Tai; Yamada, Koji; Wada, Kazumi; Ishikawa, Yasuhiko

    2016-04-01

    A new structure is examined for low-voltage and low-noise Ge-based avalanche photodiodes (APDs) on Si, where a Ge/graded-SiGe heterostructure is used as the multiplication layer of a separate-absorption-carrier-multiplication structure. The Ge/SiGe heterojunction multiplication layer is theoretically shown to be useful for preferentially enhancing impact ionization for photogenerated holes injected from the Ge optical-absorption layer via the graded SiGe, reflecting the valence band discontinuity at the Ge/SiGe interface. This property is effective not only for the reduction of operation voltage/electric field strength in Ge-based APDs but also for the reduction of excess noise resulting from the ratio of the ionization coefficients between electrons and holes being far from unity. Such Ge/graded-SiGe heterostructures are successfully fabricated by ultrahigh-vacuum chemical vapor deposition. Preliminary pin diodes having a Ge/graded-SiGe multiplication layer act reasonably as photodetectors, showing a multiplication gain larger than those for diodes without the Ge/SiGe heterojunction.

  5. GeO{sub x} interfacial layer scavenging remotely induced by metal electrode in metal/HfO{sub 2}/GeO{sub x}/Ge capacitors

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Taehoon; Jung, Yong Chan; Seong, Sejong; Ahn, Jinho, E-mail: jhahn@hanyang.ac.kr [Department of Materials Science and Engineering, Hanyang University, Seoul 04763 (Korea, Republic of); Lee, Sung Bo [Department of Materials Science and Engineering and Research Institute of Advanced Materials (RIAM), Seoul National University, Seoul 08826 (Korea, Republic of); Park, In-Sung, E-mail: parkis77@hanyang.ac.kr [Department of Materials Science and Engineering, Hanyang University, Seoul 04763 (Korea, Republic of); Institute of Nano Science and Technology, Hanyang University, Seoul 04763 (Korea, Republic of)

    2016-07-11

    The metal gate electrodes of Ni, W, and Pt have been investigated for their scavenging effect: a reduction of the GeO{sub x} interfacial layer (IL) between HfO{sub 2} dielectric and Ge substrate in metal/HfO{sub 2}/GeO{sub x}/Ge capacitors. All the capacitors were fabricated using the same process except for the material used in the metal electrodes. Capacitance-voltage measurements, scanning transmission electron microscopy, and electron energy loss spectroscopy were conducted to confirm the scavenging of GeO{sub x} IL. Interestingly, these metals are observed to remotely scavenge the interfacial layer, reducing its thickness in the order of Ni, W, and then Pt. The capacitance equivalent thickness of these capacitors with Ni, W, and Pt electrodes are evaluated to be 2.7 nm, 3.0 nm, and 3.5 nm, and each final remnant physical thickness of GeO{sub x} IL layer is 1.1 nm 1.4 nm, and 1.9 nm, respectively. It is suggested that the scavenging effect induced by the metal electrodes is related to the concentration of oxygen vacancies generated by oxidation reaction at the metal/HfO{sub 2} interface.

  6. <300> GeV team

    CERN Multimedia

    CERN PhotoLab

    1971-01-01

    The 300 GeV team had been assembled. In the photograph are Hans Horisberger, Clemens Zettler, Roy Billinge, Norman Blackburne, John Adams, Hans-Otto Wuster, Lars Persson, Bas de Raad, Hans Goebel, Simon Van der Meer.

  7. Phosphorus atomic layer doping in SiGe using reduced pressure chemical vapor deposition

    International Nuclear Information System (INIS)

    Yamamoto, Yuji; Heinemann, Bernd; Murota, Junichi; Tillack, Bernd

    2014-01-01

    Phosphorus (P) atomic layer doping in SiGe is investigated at temperatures between 100 °C to 600 °C using a single wafer reduced pressure chemical vapor deposition system. SiGe(100) surface is exposed to PH 3 at different PH 3 partial pressures by interrupting SiGe growth. The impact of the SiGe buffer/cap growth condition (total pressure/SiGe deposition precursors) on P adsorption, incorporation, and segregation are investigated. In the case of SiH 4 -GeH 4 -H 2 gas system, steeper P spikes due to lower segregation are observed by SiGe cap deposition at atmospheric (ATM) pressure compared with reduced pressure (RP). The steepness of P spike of ∼ 5.7 nm/dec is obtained for ATM pressure without reducing deposition temperature. This result may be due to the shift of equilibrium of P adsorption/desorption to desorption direction by higher H 2 pressure. Using Si 2 H 6 -GeH 4 -H 2 gas system for SiGe cap deposition in RP, lowering the SiGe growth temperature is possible, resulting in higher P incorporation and steeper P profile due to reduced desorption and segregation. In the case of Si 2 H 6 -GeH 4 -H 2 gas system, the P dose could be simulated assuming a Langmuir-type kinetics model. Incorporated P shows high electrical activity, indicating P is adsorbed mostly in lattice position. - Highlights: • Phosphorus (P) atomic layer doping in SiGe (100) is investigated using CVD. • P adsorption is suppressed by the hydrogen termination of Ge surface. • By SiGe cap deposition at atmospheric pressure, P segregation was suppressed. • By using Si 2 H 6 -based SiGe cap, P segregation was also suppressed. • The P adsorption process is self-limited and follows Langmuir-type kinetics model

  8. Superthin Solar Cells Based on AIIIBV/Ge Heterostructures

    Science.gov (United States)

    Pakhanov, N. A.; Pchelyakov, O. P.; Vladimirov, V. M.

    2017-11-01

    A comparative analysis of the prospects of creating superthin, light-weight, and highly efficient solar cells based on AIIIBV/InGaAs and AIIIBV/Ge heterostructures is performed. Technological problems and prospects of each variant are discussed. A method of thinning of AIIIBV/Ge heterostructures with the use of an effective temporary carrier is proposed. The method allows the process to be performed almost with no risk of heterostructure fracture, thinning of the Ge junction down to several tens of micrometers (or even several micrometers), significant enhancement of the yield of good structures, and also convenient and reliable transfer of thinned solar cells to an arbitrary light and flexible substrate. Such a technology offers a possibility of creating high-efficiency thin and light solar cells for space vehicles on the basis of mass-produced AIIIBV/Ge heterostructures.

  9. Measurement of energy transitions for the decay radiations of 75Ge and 69Ge in a high purity germanium detector

    Science.gov (United States)

    Aydın, Güral; Usta, Metin; Oktay, Adem

    2018-06-01

    Photoactivation experiments have a wide range of application areas in nuclear, particle physics, and medical physics such as measuring energy levels and half-lifes of nuclei, experiments for understanding imaging methods in medicine, isotope production for patient treatment, radiation security and transportation, radiation therapy, and astrophysics processes. In this study, some energy transition values of the decay radiations of 75Ge and 69Ge, which are the products of photonuclear reactions (γ, n) with germanium isotopes (75Ge and 69Ge), were measured. The gamma spectrum as a result of atomic transitions were analysed by using a high purity semiconductor germanium detector and the energy transition values which are presented here were compared with the ones which are the best in literature. It was observed that the results presented are in agreement with literature in error range and some results have better precisions.

  10. Extended deep level defects in Ge-condensed SiGe-on-Insulator structures fabricated using proton and helium implantations

    International Nuclear Information System (INIS)

    Kwak, D.W.; Lee, D.W.; Oh, J.S.; Lee, Y.H.; Cho, H.Y.

    2012-01-01

    SiGe-on-Insulator (SGOI) structures were created using the Ge condensation method, where an oxidation process is performed on the SiGe/Si structure. This method involves rapid thermal chemical vapor deposition and H + /He + ion-implantations. Deep level defects in these structures were investigated using deep level transient spectroscopy (DLTS) by varying the pulse injection time. According to the DLTS measurements, a deep level defect induced during the Ge condensation process was found at 0.28 eV above the valence band with a capture cross section of 2.67 × 10 −17 cm 2 , two extended deep levels were also found at 0.54 eV and 0.42 eV above the valence band with capture cross sections of 3.17 × 10 −14 cm 2 and 0.96 × 10 −15 cm 2 , respectively. In the SGOI samples with ion-implantation, the densities of the newly generated defects as well as the existing defects were decreased effectively. Furthermore, the Coulomb barrier heights of the extended deep level defects were drastically reduced. Thus, we suggest that the Ge condensation method with H + ion implantation could reduce deep level defects generated from the condensation and control the electrical properties of the condensed SiGe layers. - Highlights: ► We have fabricated low-defective SiGe-on-Insulator (SGOI) with implantation method. ► H + and He + -ions are used for ion-implantation method. ► We have investigated the deep level defects of SGOI layers. ► Ge condensation method using H + ion implantation could reduce extended defects. ► They could enhance electrical properties.

  11. Growth and characterization of Ge nanostructures selectively grown on patterned Si

    International Nuclear Information System (INIS)

    Cheng, M.H.; Ni, W.X.; Luo, G.L.; Huang, S.C.; Chang, J.J.; Lee, C.Y.

    2008-01-01

    By utilizing different distribution of strain fields around the edges of oxide, which are dominated by a series of sizes of oxide-patterned windows, long-range ordered self-assembly Ge nanostructures, such as nano-rings, nano-disks and nano-dots, were selectively grown by ultra high vacuum chemical vapor deposition (UHV-CVD) on Si (001) substrates. High-resolution double-crystal symmetrical ω/2θ scans and two-dimensional reciprocal space mapping (2D-RSM) technologies employing the triple axis X-ray diffractometry have been used to evaluate the quality and strain status of as-deposited as well as in-situ annealed Ge nanostructures. Furthermore, we also compare the quality and strain status of Ge epilayers grown on planar unpatterned Si substrates. It was found that the quality of all Ge epitaxial structures is improved after in-situ annealing process and the quality of Ge nano-disk structures is better than that of Ge epilayers on planar unpatterned Si substrates, because oxide sidewalls are effective dislocation sinks. We also noted that the degree of relaxation for as-deposited Ge epilayers on planar unpatterned Si substrates is less than that for as-deposited Ge nano-disk structures. After in-situ annealing process, all Ge epitaxial structures are almost at full relaxation whatever Ge epitaxial structures grew on patterned or unpatterned Si substrates

  12. Separation of extrinsic and intrinsic plasmon excitations in Ge KLL Auger spectra

    International Nuclear Information System (INIS)

    Berenyi, Z.; Aszalos-Kiss, B.; Csik, A.; Toth, J.; Koever, L.; Varga, D.

    2002-01-01

    The nature of the Ge satellite structure and the contributions from extrinsic and intrinsic processes were investigated using the ESA-31 electron spectrometer. These measurements are providing the first high energy resolution Ge KLL data. The intensity ratio of the plasmon peaks induced by intrinsic and extrinsic excitation processes is found. (R.P.)

  13. Total dose hardness of a commercial SiGe BiCMOS technology

    International Nuclear Information System (INIS)

    Van Vonno, N.; Lucas, R.; Thornberry, D.

    1999-01-01

    Over the past decade SiGe HBT technology has progress from the laboratory to actual commercial applications. When integrated into a BiMOS process, this technology has applications in low-cost space systems. In this paper, we report results of total dose testing of a SiGe/CMOS process accessible through a commercial foundry. (authors)

  14. Fabrication of multilayered Ge nanocrystals embedded in SiOxGeNy films

    International Nuclear Information System (INIS)

    Gao Fei; Green, Martin A.; Conibeer, Gavin; Cho, Eun-Chel; Huang Yidan; Perez-Wurfl, Ivan; Flynn, Chris

    2008-01-01

    Multilayered Ge nanocrystals embedded in SiO x GeN y films have been fabricated on Si substrate by a (Ge + SiO 2 )/SiO x GeN y superlattice approach, using a rf magnetron sputtering technique with a Ge + SiO 2 composite target and subsequent thermal annealing in N 2 ambient at 750 deg. C for 30 min. X-ray diffraction (XRD) measurement indicated the formation of Ge nanocrystals with an average size estimated to be 5.4 nm. Raman scattering spectra showed a peak of the Ge-Ge vibrational mode downward shifted to 299.4 cm -1 , which was caused by quantum confinement of phonons in the Ge nanocrystals. Transmission electron microscopy (TEM) revealed that Ge nanocrystals were confined in (Ge + SiO 2 ) layers. This superlattice approach significantly improved both the size uniformity of Ge nanocrystals and their uniformity of spacing on the 'Z' growth direction

  15. Structural and phonon transmission study of Ge-Au-Ge eutectically bonded interfaces

    International Nuclear Information System (INIS)

    Knowlton, W.B.; Lawrence Berkeley Lab., CA

    1995-07-01

    This thesis presents a structural analysis and phonon transparency investigation of the Ge-Au-Ge eutectic bond interface. Interface development was intended to maximize the interfacial ballistic phonon transparency to enhance the detection of the dark matter candidate WIMPs. The process which was developed provides an interface which produces minimal stress, low amounts of impurities, and insures Ge lattice continuity through the interface. For initial Au thicknesses of greater than 1,000 angstrom Au per substrate side, eutectic epitaxial growth resulted in a Au dendritic structure with 95% cross sectional and 90% planar Au interfacial area coverages. In sections in which Ge bridged the interface, lattice continuity across the interface was apparent. Epitaxial solidification of the eutectic interface with initial Au thicknesses < 500 A per substrate side produced Au agglomerations thereby reducing the Au planar interfacial area coverage to as little as 30%. The mechanism for Au coalescence was attributed to lateral diffusion of Ge and Au in the liquid phase during solidification. Phonon transmission studies were performed on eutectic interfaces with initial Au thicknesses of 1,000 angstrom, 500 angstrom, and 300 angstrom per substrate side. Phonon imaging of eutectically bonded samples with initial Au thicknesses of 300 angstrom/side revealed reproducible interfacial percent phonon transmissions from 60% to 70%. Line scan phonon imaging verified the results. Phonon propagation TOF spectra distinctly showed the predominant phonon propagation mode was ballistic. This was substantiated by phonon focusing effects apparent in the phonon imaging data. The degree of interface transparency to phonons and resulting phonon propagation modes correlate with the structure of the interface following eutectic solidification. Structural studies of samples with initial Au thickness of 1,000 angstrom/side appear to correspond with the phonon transmission study

  16. Structural and phonon transmission study of Ge-Au-Ge eutectically bonded interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Knowlton, W.B. [Univ. of California, Berkeley, CA (United States). Dept. of Materials Science and Mineral Engineering]|[Lawrence Berkeley Lab., CA (United States). Materials Sciences Div.

    1995-07-01

    This thesis presents a structural analysis and phonon transparency investigation of the Ge-Au-Ge eutectic bond interface. Interface development was intended to maximize the interfacial ballistic phonon transparency to enhance the detection of the dark matter candidate WIMPs. The process which was developed provides an interface which produces minimal stress, low amounts of impurities, and insures Ge lattice continuity through the interface. For initial Au thicknesses of greater than 1,000 {angstrom} Au per substrate side, eutectic epitaxial growth resulted in a Au dendritic structure with 95% cross sectional and 90% planar Au interfacial area coverages. In sections in which Ge bridged the interface, lattice continuity across the interface was apparent. Epitaxial solidification of the eutectic interface with initial Au thicknesses < 500 A per substrate side produced Au agglomerations thereby reducing the Au planar interfacial area coverage to as little as 30%. The mechanism for Au coalescence was attributed to lateral diffusion of Ge and Au in the liquid phase during solidification. Phonon transmission studies were performed on eutectic interfaces with initial Au thicknesses of 1,000 {angstrom}, 500 {angstrom}, and 300 {angstrom} per substrate side. Phonon imaging of eutectically bonded samples with initial Au thicknesses of 300 {angstrom}/side revealed reproducible interfacial percent phonon transmissions from 60% to 70%. Line scan phonon imaging verified the results. Phonon propagation TOF spectra distinctly showed the predominant phonon propagation mode was ballistic. This was substantiated by phonon focusing effects apparent in the phonon imaging data. The degree of interface transparency to phonons and resulting phonon propagation modes correlate with the structure of the interface following eutectic solidification. Structural studies of samples with initial Au thickness of 1,000 {angstrom}/side appear to correspond with the phonon transmission study.

  17. Study of quark line selection rule (OZI rule) in the hadron processes. 3. Study of the OZI rule in production of φ and ω mesons in diffractive p N interactions at the energy of 70 GeV

    International Nuclear Information System (INIS)

    Balats, M.Ya.; Vavilov, D.V.; Viktorov, V.A.

    1996-01-01

    Ratio of cross sections for pφ- and pω-production in diffractive p N-interactions was measured with the Sphinx facility at the energy of E p = 70 GeV. Results of this work demonstrate significant OZI rule violation in proton-induced reactions. 12 refs., 8 figs

  18. Investigation of the OZI selection rule for connected quark diagrams in hadronic processes: 3. Diffractive φ and ω production in pN collisions at 70 GeV

    International Nuclear Information System (INIS)

    1996-01-01

    The ratio between the cross sections for the diffractive production of pφ and pω systems in pN collisions at Ep=70 GeV is determined by using data from the SPHINX detector. A significant violation of the OZI rule in proton-induced transitions is observed

  19. Silicon Based Mid Infrared SiGeSn Heterostructure Emitters and Detectors

    Science.gov (United States)

    2016-05-16

    AFRL-AFOSR-JP-TR-2016-0054 Silicon based mid infrared SiGeSn heterostrcture emitters and detectors Greg Sun UNIVERSITY OF MASSACHUSETTS Final Report... Silicon Based Mid Infrared SiGeSn Heterostructure Emitters and Detectors ” February 10, 2016 Principal Investigator: Greg Sun Engineering...diodes are incompatible with the CMOS process and therefore cannot be easily integrated with Si electronics . The GeSn mid IR detectors developed in

  20. Structural evolution of Ge-rich Si1−xGex films deposited by jet-ICPCVD

    Directory of Open Access Journals (Sweden)

    Yu Wang

    2015-11-01

    Full Text Available Amorphous Ge-rich Si1−xGex films with local Ge-clustering were deposited by dual-source jet-type inductively coupled plasma chemical-vapor deposition (jet-ICPCVD. The structural evolution of the deposited films annealed at various temperatures (Ta is investigated. Experimental results indicate that the crystallization occurs to form Ge and Si clusters as Ta = 500 °C. With raising Ta up to 900 °C, Ge clusters percolate together and Si diffuses and redistributes to form a Ge/SiGe core/shell structure, and some Ge atoms partially diffuse to the surface as a result of segregation. The present work will be helpful in understanding the structural evolution process of a hybrid SiGe films and beneficial for further optimizing the microstructure and properties.

  1. Toepassing geïntegreerde maatregelen geïnvestariseerd

    NARCIS (Netherlands)

    Heijne, B.

    2009-01-01

    Kennis over 'good practices' en 'best practices' van geïntegreerde bedrijfsstrategieën verspreidt zich snel over Europa. Dat is één van de conclusies van een inventarisatie binnen het project Endure. Het aanplanten van minder vatbare of resistente rassen blijkt weinig toegepast te worden in de

  2. Direct band gap light emission and detection at room temperature in bulk germanium diodes with HfGe/Ge/TiN structure

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Dong, E-mail: wang.dong.539@m.kyushu-u.ac.jp [Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, 6-1 Kasuga-koen, Kasuga, Fukuoka 816-8580 (Japan); Maekura, Takayuki [Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, 6-1 Kasuga-koen, Kasuga, Fukuoka 816-8580 (Japan); Yamamoto, Keisuke; Nakashima, Hiroshi [Art, Science and Technology Center for Cooperative Research, Kyushu University, 6-1 Kasuga-koen, Kasuga, Fukuoka 816-8580 (Japan)

    2016-03-01

    Direct band gap (DBG) electroluminescence (EL) and photo detection were studied at room temperature for n-type bulk germanium (Ge) diodes with a fin type lateral HfGe/Ge/TiN structure. DBG EL spectra peaked at 1.55 μm were clearly observed due to small hole and electron barrier heights of HfGe/Ge and TiN/Ge contacts. DBG EL peak intensity increased with increasing doping level of Ge substrate due to increased electron population in direct conduction band. The integrated intensity of DBG EL spectrum is proportional to the area of active region, implying a good surface-uniformity of EL efficiency. Small dark current intensity was measured as 2.4 × 10{sup −7} A under a reverse bias voltage of − 1 V, corresponding to dark current densities of 5.3 × 10{sup −10} A/μm or 3.2 × 10{sup −10} A/μm{sup 2}. At the wavelength of 1.55 μm, a linear dependence of photo current intensity on laser power was observed with a responsivity of 0.44 A/W at a reverse bias voltage of − 1 V. - Highlights: • Lateral HfGe/Ge/TiN diodes were fabricated on bulk Ge substrates. • The highest temperature was 400 °C for the entire fabrication process. • Electroluminescence spectra were measured for HfGe/Ge/TiN diodes with different parameters. • Dark current densities were 5.3 × 10{sup −10} A/μm or 3.2 × 10{sup −10} A/μm{sup 2} at − 1 V. • Responsivity was 0.44 A/W, corresponding to an external quantum efficiency of 35.2%.

  3. Generation of uniaxial tensile strain of over 1% on a Ge substrate for short-channel strained Ge n-type Metal–Insulator–Semiconductor Field-Effect Transistors with SiGe stressors

    International Nuclear Information System (INIS)

    Moriyama, Yoshihiko; Kamimuta, Yuuichi; Ikeda, Keiji; Tezuka, Tsutomu

    2012-01-01

    Tensile strain of over 1% in Ge stripes sandwiched between a pair of SiGe source-drain stressors was demonstrated. The Metal–Oxide–Semiconductor Field-Effect Transistor (MOSFET)-like structures were fabricated on a (001)-Ge substrate having SiO 2 dummy-gate stripes with widths down to 26 nm. Recess-regions adjacent to the dummy-gate stripes were formed by an anisotropic wet etching technique. A damage-free and well-controlled anisotropic wet etching process is developed in order to avoid plasma-induced damage during a conventional Reactive-ion Etching process. The SiGe stressors were epitaxially grown on the recesses to simulate strained Ge n-channel Metal–Insulator–Semiconductor Field-Effect Transistors (MISFETs) having high electron mobility. A micro-Raman spectroscopy measurement revealed tensile strain in the narrow Ge regions which became higher for narrower regions. Tensile strain of up to 1.2% was evaluated from the measurement under an assumption of uniaxial strain configuration. These results strongly suggest that higher electron mobility than the upper limit for a Si-MOSFET is obtainable in short-channel strained Ge-nMISFETs with the embedded SiGe stressors.

  4. Epitaxial growth of Si1−xGex alloys and Ge on Si(100) by electron-cyclotron-resonance Ar plasma chemical vapor deposition without substrate heating

    International Nuclear Information System (INIS)

    Ueno, Naofumi; Sakuraba, Masao; Murota, Junichi; Sato, Shigeo

    2014-01-01

    By using electron-cyclotron-resonance (ECR) Ar-plasma chemical vapor deposition (CVD) without substrate heating, the epitaxial growth process of Si 1−x Ge x alloy and Ge films deposited directly on dilute-HF-treated Si(100) was investigated. From the reflection high energy electron diffraction patterns of the deposited Si 1−x Ge x alloy (x = 0.50, 0.75) and Ge films on Si(100), it is confirmed that epitaxial growth can be realized without substrate heating, and that crystallinity degradation at larger film thickness is observed. The X-ray diffraction peak of the epitaxial films reveals the existence of large compressive strain, which is induced by lattice matching with the Si(100) substrate at smaller film thicknesses, as well as strain relaxation behavior at larger film thicknesses. The Ge fraction of Si 1−x Ge x thin film is in good agreement with the normalized GeH 4 partial pressure. The Si 1−x Ge x deposition rate increases with an increase of GeH 4 partial pressure. The GeH 4 partial pressure dependence of partial deposition rates [(Si or Ge fraction) × (Si 1−x Ge x thickness) / (deposition time)] shows that the Si partial deposition rate is slightly enhanced by the existence of Ge. From these results, it is proposed that the ECR-plasma CVD process can be utilized for Ge fraction control in highly-strained heterostructure formation of group IV semiconductors. - Highlights: • Si 1−x Ge x alloy and Ge were epitaxially grown on Si(100) without substrate heating. • Large strain and its relaxation behavior can be observed by X-ray diffraction. • Ge fraction of Si 1−x Ge x is equal to normalized GeH 4 partial pressure. • Si partial deposition rate is slightly enhanced by existence of Ge

  5. The Low Temperature Epitaxy of Strained GeSn Layers Using RTCVD System

    Science.gov (United States)

    Kil, Yeon-Ho; Yuk, Sim-Hoon; Jang, Han-Soo; Lee, Sang-Geul; Choi, Chel-Jong; Shim, Kyu-Hwan

    2018-03-01

    We have investigated the low temperature (LT) growth of GeSn-Ge-Si structures using rapid thermal chemical vapor deposition system utilizing Ge2H6 and SnCl4 as the reactive precursors. Due to inappropriate phenomena, such as, Ge etch and Sn segregation, it was hard to achieve high quality GeSn epitaxy at the temperature > 350 °C. On the contrary, we found that the SnCl4 promoted the reaction of Ge2H6 precursors in a certain process condition of LT, 240-360 °C. In return, we could perform the growth of GeSn epi layer with 7.7% of Sn and its remaining compressive strain of 71.7%. The surface propagated defects were increased with increasing the Sn content in the GeSn layer confirmed by TEM analysis. And we could calculate the activation energies at lower GeSn growth temperature regime using by Ge2H6 and SnCl4 precursors about 0.43 eV.

  6. GeSn-on-insulator substrate formed by direct wafer bonding

    Energy Technology Data Exchange (ETDEWEB)

    Lei, Dian; Wang, Wei; Gong, Xiao, E-mail: elegong@nus.edu.sg, E-mail: yeo@ieee.org; Yeo, Yee-Chia, E-mail: elegong@nus.edu.sg, E-mail: yeo@ieee.org [Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117576 (Singapore); Lee, Kwang Hong; Wang, Bing [Low Energy Electronic Systems (LEES), Singapore MIT Alliance for Research and Technology (SMART), 1 CREATE Way, #10-01 CREATE Tower, Singapore 138602 (Singapore); Bao, Shuyu [Low Energy Electronic Systems (LEES), Singapore MIT Alliance for Research and Technology (SMART), 1 CREATE Way, #10-01 CREATE Tower, Singapore 138602 (Singapore); School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Tan, Chuan Seng [School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore)

    2016-07-11

    GeSn-on-insulator (GeSnOI) on Silicon (Si) substrate was realized using direct wafer bonding technique. This process involves the growth of Ge{sub 1-x}Sn{sub x} layer on a first Si (001) substrate (donor wafer) followed by the deposition of SiO{sub 2} on Ge{sub 1-x}Sn{sub x}, the bonding of the donor wafer to a second Si (001) substrate (handle wafer), and removal of the Si donor wafer. The GeSnOI material quality is investigated using high-resolution transmission electron microscopy, high-resolution X-ray diffraction (HRXRD), atomic-force microscopy, Raman spectroscopy, and spectroscopic ellipsometry. The Ge{sub 1-x}Sn{sub x} layer on GeSnOI substrate has a surface roughness of 1.90 nm, which is higher than that of the original Ge{sub 1-x}Sn{sub x} epilayer before transfer (surface roughness is 0.528 nm). The compressive strain of the Ge{sub 1-x}Sn{sub x} film in the GeSnOI is as low as 0.10% as confirmed using HRXRD and Raman spectroscopy.

  7. Propagation of GeV neutrinos through Earth

    Science.gov (United States)

    Olivas, Yaithd Daniel; Sahu, Sarira

    2018-06-01

    We have studied the Earth matter effect on the oscillation of upward going GeV neutrinos by taking into account the three active neutrino flavors. For neutrino energy in the range 3 to 12 GeV we observed three distinct resonant peaks for the oscillation process νe ↔νμ,τ in three distinct densities. However, according to the most realistic density profile of the Earth, the second peak at neutrino energy 6.18 GeV corresponding to the density 6.6 g/cm3 does not exist. So the resonance at this energy can not be of MSW-type. For the calculation of observed flux of these GeV neutrinos on Earth, we considered two different flux ratios at the source, the standard scenario with the flux ratio 1 : 2 : 0 and the muon damped scenario with 0 : 1 : 0. It is observed that at the detector while the standard scenario gives the observed flux ratio 1 : 1 : 1, the muon damped scenario has a different ratio. For muon damped case with Eν 20 GeV, we get the average Φνe ∼ 0 and Φνμ ≃Φντ ≃ 0.45. The upcoming PINGU will be able to shed more light on the nature of the resonance in these GeV neutrinos and hopefully will also be able to discriminate among different processes of neutrino production at the source in GeV energy range.

  8. Neutron transmutation doped Ge bolometers

    Science.gov (United States)

    Haller, E. E.; Kreysa, E.; Palaio, N. P.; Richards, P. L.; Rodder, M.

    1983-01-01

    Some conclusions reached are as follow. Neutron Transmutation Doping (NTD) of high quality Ge single crystals provides perfect control of doping concentration and uniformity. The resistivity can be tailored to any given bolometer operating temperature down to 0.1 K and probably lower. The excellent uniformity is advantaged for detector array development.

  9. Poly-SiGe for MEMS-above-CMOS sensors

    CERN Document Server

    Gonzalez Ruiz, Pilar; Witvrouw, Ann

    2014-01-01

    Polycrystalline SiGe has emerged as a promising MEMS (Microelectromechanical Systems) structural material since it provides the desired mechanical properties at lower temperatures compared to poly-Si, allowing the direct post-processing on top of CMOS. This CMOS-MEMS monolithic integration can lead to more compact MEMS with improved performance. The potential of poly-SiGe for MEMS above-aluminum-backend CMOS integration has already been demonstrated. However, aggressive interconnect scaling has led to the replacement of the traditional aluminum metallization by copper (Cu) metallization, due to its lower resistivity and improved reliability. Poly-SiGe for MEMS-above-CMOS sensors demonstrates the compatibility of poly-SiGe with post-processing above the advanced CMOS technology nodes through the successful fabrication of an integrated poly-SiGe piezoresistive pressure sensor, directly fabricated above 0.13 m Cu-backend CMOS. Furthermore, this book presents the first detailed investigation on the influence o...

  10. Impacts of doping on epitaxial germanium thin film quality and Si-Ge interdiffusion

    KAUST Repository

    Zhou, Guangnan

    2018-04-03

    Ge-on-Si structures with three different dopants (P, As and B) and those without intentional doping were grown, annealed and characterized by several different material characterization methods. All samples have a smooth surface (roughness < 1.5 nm), and the Ge films are almost entirely relaxed. B doped Ge films have threading dislocations above 1 × 10 cm, while P and As doping can reduce the threading dislocation density to be less than 10 cm without annealing. The interdiffusion of Si and Ge of different films have been investigated experimentally and theoretically. A quantitative model of Si-Ge interdiffusion under extrinsic conditions across the full x range was established including the dislocationmediated diffusion. The Kirkendall effect has been observed. The results are of technical significance for the structure, doping, and process design of Ge-on-Si based devices, especially for photonic applications.

  11. Impacts of doping on epitaxial germanium thin film quality and Si-Ge interdiffusion

    KAUST Repository

    Zhou, Guangnan; Lee, Kwang Hong; Anjum, Dalaver H.; Zhang, Qiang; Zhang, Xixiang; Tan, Chuan Seng; Xia, Guangrui

    2018-01-01

    Ge-on-Si structures with three different dopants (P, As and B) and those without intentional doping were grown, annealed and characterized by several different material characterization methods. All samples have a smooth surface (roughness < 1.5 nm), and the Ge films are almost entirely relaxed. B doped Ge films have threading dislocations above 1 × 10 cm, while P and As doping can reduce the threading dislocation density to be less than 10 cm without annealing. The interdiffusion of Si and Ge of different films have been investigated experimentally and theoretically. A quantitative model of Si-Ge interdiffusion under extrinsic conditions across the full x range was established including the dislocationmediated diffusion. The Kirkendall effect has been observed. The results are of technical significance for the structure, doping, and process design of Ge-on-Si based devices, especially for photonic applications.

  12. Vertically grown Ge nanowire Schottky diodes on Si and Ge substrates

    Science.gov (United States)

    Chandra, Nishant; Tracy, Clarence J.; Cho, Jeong-Hyun; Picraux, S. T.; Hathwar, Raghuraj; Goodnick, Stephen M.

    2015-07-01

    The processing and performance of Schottky diodes formed from arrays of vertical Ge nanowires (NWs) grown on Ge and Si substrates are reported. The goal of this work is to investigate CMOS compatible processes for integrating NWs as components of vertically scaled integrated circuits, and elucidate transport in vertical Schottky NWs. Vertical phosphorus (P) doped Ge NWs were grown using vapor-liquid-solid epitaxy, and nickel (Ni)-Ge Schottky contacts were made to the tops of the NWs. Current-voltage (I-V) characteristics were measured for variable ranges of NW diameters and numbers of nanowires in the arrays, and the I-V characteristics were fit using modified thermionic emission theory to extract the barrier height and ideality factor. As grown NWs did not show rectifying behavior due to the presence of heavy P side-wall doping during growth, resulting in a tunnel contact. After sidewall etching using a dilute peroxide solution, rectifying behavior was obtained. Schottky barrier heights of 0.3-0.4 V and ideality factors close to 2 were extracted using thermionic emission theory, although the model does not give an accurate fit across the whole bias range. Attempts to account for enhanced side-wall conduction due to non-uniform P doping profile during growth through a simple shunt resistance improve the fit, but are still insufficient to provide a good fit. Full three-dimensional numerical modeling using Silvaco Atlas indicates that at least part of this effect is due to the presence of fixed charge and acceptor like traps on the NW surface, which leads to effectively high ideality factors.

  13. GE Healthcare | College of Engineering & Applied Science

    Science.gov (United States)

    Olympiad Girls Who Code Club FIRST Tech Challenge NSF I-Corps Site of Southeastern Wisconsin UW-Milwaukee ; Talent GE Healthcare is the founding partner of the Center for Advanced Embedded Systems (CAES), formerly GE Healthcare's needs for talent. Business Corporate Partners ANSYS Institute GE Healthcare Catalyst

  14. Radiation emission from wrinkled SiGe/SiGe nanostructure

    Czech Academy of Sciences Publication Activity Database

    Fedorchenko, Alexander I.; Cheng, H. H.; Sun, G.; Soref, R. A.

    2010-01-01

    Roč. 96, č. 11 (2010), s. 113104-113107 ISSN 0003-6951 Institutional research plan: CEZ:AV0Z20760514 Keywords : SiGe wrinkled nanostructures * si-based optical emitter * synchrotron radiation Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.820, year: 2010 http://apl.aip.org/resource/1/applab/v96/i11/p113104_s1?isAuthorized=no

  15. Selective epitaxial growth properties and strain characterization of Si1- x Ge x in SiO2 trench arrays

    Science.gov (United States)

    Koo, Sangmo; Jang, Hyunchul; Ko, Dae-Hong

    2017-04-01

    In this study, we investigated the formation of a Si1- x Ge x fin structure in SiO2 trench arrays via an ultra-high-vacuum chemical-vapor deposition (UHV-CVD) selective epitaxial growth (SEG) process. Defect generation and microstructures of Si1- x Ge x fin structures with different Ge concentrations ( x = 0.2, 0.3 and 0.45) were examined. In addition, the strain evolution of a Si1- x Ge x fin structure was analyzed by using reciprocal space mapping (RSM). An (111) facet was formed from the Si1- x Ge x epi-layer and SiO2 trench wall interface to minimize the interface and the surface energy. The Si1- x Ge x fin structures were fully relaxed along the direction perpendicular to the trenches regardless of the Ge concentration. On the other hand, the fin structures were fully or partially strained along the direction parallel to the trenches depending on the Ge concentration: fully strained Si0.8Ge0.2 and Si0.7Ge0.3, and a Si0.55Ge0.45 strain-relaxed buffer. We further confirmed that the strain on the Si1- x Ge x fin structures remained stable after oxide removal and H2/N2 post-annealing.

  16. Formation of the low-resistivity compound Cu_3Ge by low-temperature treatment in an atomic hydrogen flux

    International Nuclear Information System (INIS)

    Erofeev, E. V.; Kazimirov, A. I.; Fedin, I. V.; Kagadei, V. A.

    2016-01-01

    The systematic features of the formation of the low-resistivity compound Cu_3Ge by low-temperature treatment of a Cu/Ge two-layer system in an atomic hydrogen flux are studied. The Cu/Ge two-layer system is deposited onto an i-GaAs substrate. Treatment of the Cu/Ge/i-GaAs system, in which the layer thicknesses are, correspondingly, 122 and 78 nm, in atomic hydrogen with a flux density of 10"1"5 at cm"2 s"–"1 for 2.5–10 min at room temperature induces the interdiffusion of Cu and Ge, with the formation of a polycrystalline film containing the stoichiometric Cu_3Ge phase. The film consists of vertically oriented grains 100–150 nm in size and exhibits a minimum resistivity of 4.5 µΩ cm. Variations in the time of treatment of the Cu/Ge/i-GaAs samples in atomic hydrogen affect the Cu and Ge depth distribution, the phase composition of the films, and their resistivity. Experimental observation of the synthesis of the Cu_3Ge compound at room temperature suggests that treatment in atomic hydrogen has a stimulating effect on both the diffusion of Cu and Ge and the chemical reaction of Cu_3Ge-compound formation. These processes can be activated by the energy released upon the recombination of hydrogen atoms adsorbed at the surface of the Cu/Ge/i-GaAs sample.

  17. Photoproduction of long-lived holes and electronic processes in intrinsic electric fields seen through photoinduced absorption and dichroism in Ca sub 3 Ga sub 2 sub - sub x Mn sub x Ge sub 3 O sub 1 sub 2 garnets

    CERN Document Server

    Eremenko, V V; Kachur, I S; Piryatinskaya, V G; Ratner, A M; Kosmyna, M B; Nazarenko, B P; Puzikov, V M

    2003-01-01

    Long-lived photoinduced absorption and dichroism in the Ca sub 3 Ga sub 2 sub - sub x Mn sub x Ge sub 3 O sub 1 sub 2 garnets with x < 0.06 were examined versus temperature and pumping intensity. Unusual features of the kinetics of photoinduced phenomena are indicative of the underlying electronic processes. The comparison with the case of Ca sub 3 Mn sub 2 Ge sub 3 O sub 1 sub 2 , explored earlier by the authors, permits one to finally establish the main common mechanisms of photoinduced absorption and dichroism caused by random electric fields of photoproduced charges (hole polarons). The rate of their diffusion and relaxation through recombination is strongly influenced by the same fields, whose large statistical straggling is responsible for a broad continuous set of relaxation components (observed in the relaxation time range from 1 to about 1000 min). For Ca sub 3 Ga sub 2 sub - sub x Mn sub x Ge sub 3 O sub 1 sub 2 , the time and temperature dependences of photoinduced absorption and dichroism bear ...

  18. Magnetic properties of ultrathin Co/Ge(111) and Co/Ge(100) films

    International Nuclear Information System (INIS)

    Cheng, W. C.; Tsay, J. S.; Yao, Y. D.; Lin, K. C.; Yang, C. S.; Lee, S. F.; Tseng, T. K.; Neih, H. Y.

    2001-01-01

    The orientation of the magnetization and the occurrence of interfacial ferromagnetic inactive layers for ultrathin Co films grown on Ge(111) and Ge(100) surfaces have been studied using the in situ surface magneto-optic Kerr effect. On a Ge(111) substrate, cobalt films (≤28 monolayers) with in-plane easy axis of magnetization have been observed; however, on a Ge(100) substrate, ultrathin Co films (14 - 16 monolayers) with canted out-of-plane easy axis of magnetization were measured. The ferromagnetic inactive layers were formed due to the intermixing of Co and Ge and lowering the Curie temperature by reducing Co film thickness. The Co - Ge compound inactive layers were 3.8 monolayers thick for Co films grown on Ge(111) and 6.2 monolayers thick for Co films deposited on Ge(100). This is attributed to the difference of the density of surface atoms on Ge(111) and Ge(100). [copyright] 2001 American Institute of Physics

  19. Substrate Effects in Wideband SiGe HBT Mixer Circuits

    DEFF Research Database (Denmark)

    Johansen, Tom Keinicke; Vidkjær, Jens; Krozer, Viktor

    2005-01-01

    are also applied to predict short distance substrate coupling effects. Simulation results using extracted equivalent circuit models and substrate coupling networks are compared with experimental results obtained on a wideband mixer circuit implemented in a 0.35 μm, 60 GHz ft SiGe HBT BiCMOS process.......In this paper, the influence from substrate effects on the performance of wideband SiGe HBT mixer circuits is investigated. Equivalent circuit models including substrate networks are extracted from on-wafer test structures and compared with electromagnetic simulations. Electromagnetic simulations...

  20. Dipole Resonances of 76Ge

    Science.gov (United States)

    Ilieva, R. S.; Cooper, N.; Werner, V.; Rusev, G.; Pietralla, N.; Kelly, J. H.; Tornow, W.; Yates, S. W.; Crider, B. P.; Peters, E.

    2013-10-01

    Dipole resonances in 76Ge have been studied using the method of Nuclear Resonance Fluorescence (NRF). The experiment was performed using the Free Electron Laser facility at HI γS/TUNL, which produced linearly polarised quasi-monoenergetic photons in the 4-9 MeV energy range. Photon strength, in particular dipole strength, is an important ingredient in nuclear reaction calculations, and recent interest in its study has been stimulated by observations of a pygmy dipole resonance near the neutron separation energy Sn of certain nuclei. Furthermore, 76Ge is a candidate for 0 ν 2 β -decay. The results are complimentary to a relevant experiment done at TU Darmstadt using Bremsstrahlung beams. Single-resonance parities and a preliminary estimate of the total photo-excitation cross section will be presented. This work was supported by the U.S. DOE under grant no. DE-FG02-91ER40609.

  1. P/N InP solar cells on Ge wafers

    Science.gov (United States)

    Wojtczuk, Steven; Vernon, Stanley; Burke, Edward A.

    1994-01-01

    Indium phosphide (InP) P-on-N one-sun solar cells were epitaxially grown using a metalorganic chemical vapor deposition process on germanium (Ge) wafers. The motivation for this work is to replace expensive InP wafers, which are fragile and must be thick and therefore heavy, with less expensive Ge wafers, which are stronger, allowing use of thinner, lighter weight wafers. An intermediate InxGs1-xP grading layer starting as In(0.49)Ga(0.51) at the GaAs-coated Ge wafer surface and ending as InP at the top of the grading layer (backside of the InP cell) was used to attempt to bend some of the threading dislocations generated by lattice-mismatch between the Ge wafer and InP cell so they would be harmlessly confined in this grading layer. The best InP/Ge cell was independently measured by NASA-Lewis with a one-sun 25 C AMO efficiently measured by NASA-Lewis with a one-circuit photocurrent 22.6 mA/sq cm. We believe this is the first published report of an InP cell grown on a Ge wafer. Why get excited over a 9 percent InP/Ge cell? If we look at the cell weight and efficiency, a 9 percent InP cell on an 8 mil Ge wafer has about the same cell power density, 118 W/kg (BOL), as the best InP cell ever made, a 19 percent InP cell on an 18 mil InP wafer, because of the lighter Ge wafer weight. As cell panel materials become lighter, the cell weight becomes more important, and the advantage of lightweight cells to the panel power density becomes more important. In addition, although InP/Ge cells have a low beginning-of-life (BOL) efficiency due to dislocation defects, the InP/Ge cells are very radiation hard (end-of-life power similar to beginning-of-life). We have irradiated an InP/Ge cell with alpha particles to an equivalent fluence of 1.6 x 10(exp 16) 1 MeV electrons/sq cm and the efficiency is still 83 percent of its BOL value. At this fluence level, the power output of these InP/Ge cells matches the GaAs/Ge cell data tabulated in the JPL handbook. Data are presented

  2. Effects of C+ ion implantation on electrical properties of NiSiGe/SiGe contacts

    International Nuclear Information System (INIS)

    Zhang, B.; Yu, W.; Zhao, Q.T.; Buca, D.; Breuer, U.; Hartmann, J.-M.; Holländer, B.; Mantl, S.; Zhang, M.; Wang, X.

    2013-01-01

    We have investigated the morphology and electrical properties of NiSiGe/SiGe contact by C + ions pre-implanted into relaxed Si 0.8 Ge 0.2 layers. Cross-section transmission electron microscopy revealed that both the surface and interface of NiSiGe were improved by C + ions implantation. In addition, the effective hole Schottky barrier heights (Φ Bp ) of NiSiGe/SiGe were extracted. Φ Bp was observed to decrease substantially with an increase in C + ion implantation dose

  3. Enhanced charge storage capability of Ge/GeO2 core/shell nanostructure

    International Nuclear Information System (INIS)

    Yuan, C L; Lee, P S

    2008-01-01

    A Ge/GeO 2 core/shell nanostructure embedded in an Al 2 O 3 gate dielectrics matrix was produced. A larger memory window with good data retention was observed in the fabricated metal-insulator-semiconductor (MIS) capacitor for Ge/GeO 2 core/shell nanoparticles compared to Ge nanoparticles only, which is due to the high percentage of defects located on the surface and grain boundaries of the GeO 2 shell. We believe that the findings presented here provide physical insight and offer useful guidelines to controllably modify the charge storage properties of indirect semiconductors through defect engineering

  4. Enhanced charge storage capability of Ge/GeO(2) core/shell nanostructure.

    Science.gov (United States)

    Yuan, C L; Lee, P S

    2008-09-03

    A Ge/GeO(2) core/shell nanostructure embedded in an Al(2)O(3) gate dielectrics matrix was produced. A larger memory window with good data retention was observed in the fabricated metal-insulator-semiconductor (MIS) capacitor for Ge/GeO(2) core/shell nanoparticles compared to Ge nanoparticles only, which is due to the high percentage of defects located on the surface and grain boundaries of the GeO(2) shell. We believe that the findings presented here provide physical insight and offer useful guidelines to controllably modify the charge storage properties of indirect semiconductors through defect engineering.

  5. GeSbTe deposition for the PRAM application

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Junghyun [Nano Fabrication Center, SAIT, Suwon, P.O. Box 111 (Korea, Republic of); Choi, Sangjoon [Nano Fabrication Center, SAIT, Suwon, P.O. Box 111 (Korea, Republic of); Lee, Changsoo [Nano Fabrication Center, SAIT, Suwon, P.O. Box 111 (Korea, Republic of); Kang, Yoonho [Nano Fabrication Center, SAIT, Suwon, P.O. Box 111 (Korea, Republic of); Kim, Daeil [School of Materials Science and Engineering. University of Ulsan, San 29, Mugeo-Dong, Nam-Gu, Ulsan 680-749 (Korea, Republic of)]. E-mail: dkim84@mail.ulsan.ac.kr

    2007-02-15

    GeSbTe (GST) chalcogenide thin films for the phase-change random access memory (PRAM) were deposited by an atomic layer deposition (ALD) process. New precursors for GST thin films made with an ALD process were synthesized. Among the synthesized precursors, Ge(N(CH{sub 3}){sub 2}){sub 4}, Sb(N(CH{sub 3}){sub 2}){sub 4}, and Te(i-Pr){sub 2} (i-Pr = iso-propyl) were selected. Using the above precursors, GST thin films were deposited using an H{sub 2} plasma-assisted ALD process. Film resistivity abruptly changed after an N{sub 2} annealing process above a temperature of 350 deg. C. Cross-sectional scanning electron microscope (SEM) photographs of the GST films on the patterned substrate with aspect ratio of 7 shows that the step coverage is about 90%.

  6. Ion Beam Synthesis of Ge Nanowires. rev. ed.

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, T.

    2001-01-01

    The formation of Ge nanowires in V-grooves has been studied experimentally as well as theoretically. As substrate oxide covered Si V-grooves were used formed by anisotropic etching of (001)Si wafers and subsequent oxidation of their surface. Implantation of 1 x 10{sup 17} Ge{sup +}cm{sup -2} at 70 keV was carried out into the oxide layer covering the V-grooves. Ion irradiation induces shape changes of the V-grooves, which are captured in a novel continuum model of surface evolution. It describes theoretically the effects of sputtering, redeposition of sputtered atoms, and swelling. Thereby, the time evolution of the target surface is determined by a nonlinear integro-differential equation, which was solved numerically for the V-groove geometry. A very good agreement is achieved for the predicted surface shape and the shape observed in XTEM images. Surprisingly, the model predicts material (Si, O, Ge) transport into the V-groove bottom which also suggests an Ge accumulation there proven by STEM-EDX investigations. In this Ge rich bottom region, subsequent annealing in N{sub 2} atmosphere results in the formation of a nanowire by coalescence of Ge precipitates shown by XTEM images. The process of phase separation during the nanowire growth was studied by means of kinetic 3D lattice Monte-Carlo simulations. These simulations also indicate the disintegration of continuous wires into droplets mediated by thermal fluctuations. Energy considerations have identified a fragmentation threshold and a lower boundary for the droplet radii which were confirmed by the Monte Carlo simulation. The here given results indicate the possibility of achieving nanowires being several nanometers wide by further growth optimizations as well as chains of equally spaced clusters with nearly uniform diameter. (orig.)

  7. Effect of Ge Content on the Formation of Ge Nanoclusters in Magnetron-Sputtered GeZrOx-Based Structures

    OpenAIRE

    Khomenkova, L.; Lehninger, D.; Kondratenko, O.; Ponomaryov, S.; Gudymenko, O.; Tsybrii, Z.; Yukhymchuk, V.; Kladko, V.; von Borany, J.; Heitmann, J.

    2017-01-01

    Ge-rich ZrO2 films, fabricated by confocal RF magnetron sputtering of pure Ge and ZrO2 targets in Ar plasma, were studied by multi-angle laser ellipsometry, Raman scattering, Auger electron spectroscopy, Fourier transform infrared spectroscopy, and X-ray diffraction for varied deposition conditions and annealing treatments. It was found that as-deposited films are homogeneous for all Ge contents, thermal treatment stimulated a phase separation and a formation of crystalline Ge and ZrO2. The ?...

  8. Enhanced B doping in CVD-grown GeSn:B using B δ-doping layers

    Science.gov (United States)

    Kohen, David; Vohra, Anurag; Loo, Roger; Vandervorst, Wilfried; Bhargava, Nupur; Margetis, Joe; Tolle, John

    2018-02-01

    Highly doped GeSn material is interesting for both electronic and optical applications. GeSn:B is a candidate for source-drain material in future Ge pMOS device because Sn adds compressive strain with respect to pure Ge, and therefore can boost the Ge channel performances. A high B concentration is required to obtain low contact resistivity between the source-drain material and the metal contact. To achieve high performance, it is therefore highly desirable to maximize both the Sn content and the B concentration. However, it has been shown than CVD-grown GeSn:B shows a trade-off between the Sn incorporation and the B concentration (increasing B doping reduces Sn incorporation). Furthermore, the highest B concentration of CVD-grown GeSn:B process reported in the literature has been limited to below 1 × 1020 cm-3. Here, we demonstrate a CVD process where B δ-doping layers are inserted in the GeSn layer. We studied the influence of the thickness between each δ-doping layers and the δ-doping layers process conditions on the crystalline quality and the doping density of the GeSn:B layers. For the same Sn content, the δ-doping process results in a 4-times higher B doping than the co-flow process. In addition, a B doping concentration of 2 × 1021 cm-3 with an active concentration of 5 × 1020 cm-3 is achieved.

  9. Reduced Pressure-Chemical Vapour Deposition of Si/SiGe heterostructures for nanoelectronics

    International Nuclear Information System (INIS)

    Hartmann, J.M.; Andrieu, F.; Lafond, D.; Ernst, T.; Bogumilowicz, Y.; Delaye, V.; Weber, O.; Rouchon, D.; Papon, A.M.; Cherkashin, N.

    2008-01-01

    We have first of all quantified the impact of pressure on Si and SiGe growth kinetics. Definite growth rate and Ge concentration increases with the pressure have been evidenced at low temperatures (650-750 deg. C). By contrast, the high temperature (950-1050 deg. C) Si growth rate either increases or decreases with pressure (gaseous precursor depending). We have then described the selective epitaxial growth process we use to form Si or Si 0.7 Ge 0.3 :B raised sources and drains on ultra-thin patterned Silicon-On-Insulator (SOI) substrates. We have afterwards presented the specifics of SiGe virtual substrates and of the tensile-strained Si layers grown on top (used as templates for the elaboration of tensily strained-SOI wafers). The tensile strain, which can be tailored from 1.3 up to 3 GPa, leads to an electron mobility gain by a factor of 2 in n-Metal Oxide Semiconductor Field Effect Transistors (MOSFETs) built on top. High Ge content SiGe virtual substrates can also be used for the elaboration of compressively strained Ge channels, with impressive hole mobility gains (x9) compared to bulk Si. After that, we have described the main structural features of thick Ge layers grown directly on Si (that can be used as donor wafers for the elaboration of GeOI wafers or as the active medium of near infrared photo-detectors). Finally, we have shown how Si/SiGe multilayers can be used for the formation of high performance 3D devices such as multi-bridge channel or nano-beam gate-all-around FETs, the SiGe sacrificial layers being removed thanks to plasma dry etching, wet etching or in situ gaseous HCl etching

  10. Mushroom-free selective epitaxial growth of Si, SiGe and SiGe:B raised sources and drains

    Science.gov (United States)

    Hartmann, J. M.; Benevent, V.; Barnes, J. P.; Veillerot, M.; Lafond, D.; Damlencourt, J. F.; Morvan, S.; Prévitali, B.; Andrieu, F.; Loubet, N.; Dutartre, D.

    2013-05-01

    We have evaluated various Cyclic Selective Epitaxial Growth/Etch (CSEGE) processes in order to grow "mushroom-free" Si and SiGe:B Raised Sources and Drains (RSDs) on each side of ultra-short gate length Extra-Thin Silicon-On-Insulator (ET-SOI) transistors. The 750 °C, 20 Torr Si CSEGE process we have developed (5 chlorinated growth steps with four HCl etch steps in-between) yielded excellent crystalline quality, typically 18 nm thick Si RSDs. Growth was conformal along the Si3N4 sidewall spacers, without any poly-Si mushrooms on top of unprotected gates. We have then evaluated on blanket 300 mm Si(001) wafers the feasibility of a 650 °C, 20 Torr SiGe:B CSEGE process (5 chlorinated growth steps with four HCl etch steps in-between, as for Si). As expected, the deposited thickness decreased as the total HCl etch time increased. This came hands in hands with unforeseen (i) decrease of the mean Ge concentration (from 30% down to 26%) and (ii) increase of the substitutional B concentration (from 2 × 1020 cm-3 up to 3 × 1020 cm-3). They were due to fluctuations of the Ge concentration and of the atomic B concentration [B] in such layers (drop of the Ge% and increase of [B] at etch step locations). Such blanket layers were a bit rougher than layers grown using a single epitaxy step, but nevertheless of excellent crystalline quality. Transposition of our CSEGE process on patterned ET-SOI wafers did not yield the expected results. HCl etch steps indeed helped in partly or totally removing the poly-SiGe:B mushrooms on top of the gates. This was however at the expense of the crystalline quality and 2D nature of the ˜45 nm thick Si0.7Ge0.3:B recessed sources and drains selectively grown on each side of the imperfectly protected poly-Si gates. The only solution we have so far identified that yields a lesser amount of mushrooms while preserving the quality of the S/D is to increase the HCl flow during growth steps.

  11. GE's advanced nuclear reactor designs

    International Nuclear Information System (INIS)

    Berglund, R.C.

    1993-01-01

    The excess of US electrical generating capacity which has existed for the past 15 years is coming to an end as we enter the 1990s. Environmental and energy security issues associated with fossil fuels are kindling renewed interest in the nuclear option. The importance of these issues are underscored by the National Energy Strategy (NES) which calls for actions which open-quotes are designed to ensure that the nuclear power option is available to utilities.close quotes Utilities, utility associations, and nuclear suppliers, under the leadership of the Nuclear Power Oversight Committee (NPOC), have jointly developed a 14-point strategic plan aimed at establishing a predictable regulatory environment, standardized and pre-licensed Advanced Light Water Reactor (ALWR) nuclear plants, resolving the long-term waste management issue, and other open-quotes enabling conditions.close quotes GE is participating in this national effort and GE's family of advanced nuclear power plants feature two reactor designs, developed on a common technology base, aimed at providing a new generation of nuclear plants to provide safe, clean, economical electricity to the world's utilities in the 1990s and beyond. Together, the large-size (1300 MWe) Advanced Boiling Water Reactor (ABWR) and the small-size (600 MWe) Simplified Boiling Water Reactor (SBWR) are innovative, near-term candidates for expanding electrical generating capacity in the US and worldwide. Both possess the features necessary to do so safety, reliably, and economically

  12. Fabrication of SrGe2 thin films on Ge (100), (110), and (111) substrates

    Science.gov (United States)

    Imajo, T.; Toko, K.; Takabe, R.; Saitoh, N.; Yoshizawa, N.; Suemasu, T.

    2018-01-01

    Semiconductor strontium digermanide (SrGe2) has a large absorption coefficient in the near-infrared light region and is expected to be useful for multijunction solar cells. This study firstly demonstrates the formation of SrGe2 thin films via a reactive deposition epitaxy on Ge substrates. The growth morphology of SrGe2 dramatically changed depending on the growth temperature (300-700 °C) and the crystal orientation of the Ge substrate. We succeeded in obtaining single-oriented SrGe2 using a Ge (110) substrate at 500 °C. Development on Si or glass substrates will lead to the application of SrGe2 to high-efficiency thin-film solar cells.

  13. Neutron capture cross sections of $^{70,72,73,74,76}$ Ge at n_TOF EAR-1

    CERN Multimedia

    We propose to measure the (n;$\\gamma$ ) cross sections of the isotopes $^{70;72;73;74;76}$Ge. Neutron induced reactions on Ge are of importance for the astrophysical slow neutron capture process, which is responsible for forming about half of the overall elemental abundances heavier than Fe. The neutron capture cross section on Ge affects the abundances produced in this process for a number of heavier isotopes up to a mass number of A = 90. Additionally, neutron capture on Ge is of interest for low background experiments involving Ge detectors. Experimental cross section data presently available for Ge (n;$\\gamma$ ) are scarce and cover only a fraction of the neutron energy range of interest. (n;$\\gamma$ ) cross sections will be measured in the full energy range from 25 meV to about 200 keV at n TOF EAR-1.

  14. Search for sleptons in $e^+ e^-$ collisions at centre-of-mass energies of 161 GeV and 172 GeV

    CERN Document Server

    Barate, R; Décamp, D; Ghez, P; Goy, C; Lees, J P; Lucotte, A; Minard, M N; Nief, J Y; Pietrzyk, B; Casado, M P; Chmeissani, M; Comas, P; Crespo, J M; Delfino, M C; Fernández, E; Fernández-Bosman, M; Garrido, L; Juste, A; Martínez, M; Miquel, R; Mir, L M; Orteu, S; Padilla, C; Park, I C; Pascual, A; Perlas, J A; Riu, I; Sánchez, F; Teubert, F; Colaleo, A; Creanza, D; De Palma, M; Gelao, G; Iaselli, Giuseppe; Maggi, G; Maggi, M; Marinelli, N; Nuzzo, S; Ranieri, A; Raso, G; Ruggieri, F; Selvaggi, G; Silvestris, L; Tempesta, P; Tricomi, A; Zito, G; Huang, X; Lin, J; Ouyang, Q; Wang, T; Xie, Y; Xu, R; Xue, S; Zhang, J; Zhang, L; Zhao, W; Abbaneo, D; Alemany, R; Bazarko, A O; Becker, U; Bright-Thomas, P G; Cattaneo, M; Cerutti, F; Dissertori, G; Drevermann, H; Forty, Roger W; Frank, M; Hagelberg, R; Hansen, J B; Harvey, J; Janot, P; Jost, B; Kneringer, E; Knobloch, J; Lehraus, Ivan; Lutters, G; Mato, P; Minten, Adolf G; Moneta, L; Pacheco, A; Pusztaszeri, J F; Ranjard, F; Rizzo, G; Rolandi, Luigi; Rousseau, D; Schlatter, W D; Schmitt, M; Schneider, O; Tejessy, W; Tomalin, I R; Wachsmuth, H W; Wagner, A; Ajaltouni, Ziad J; Barrès, A; Boyer, C; Falvard, A; Ferdi, C; Gay, P; Guicheney, C; Henrard, P; Jousset, J; Michel, B; Monteil, S; Montret, J C; Pallin, D; Perret, P; Podlyski, F; Proriol, J; Rosnet, P; Rossignol, J M; Fearnley, Tom; Hansen, J D; Hansen, J R; Hansen, P H; Nilsson, B S; Rensch, B; Wäänänen, A; Daskalakis, G; Kyriakis, A; Markou, C; Simopoulou, Errietta; Siotis, I; Vayaki, Anna; Blondel, A; Brient, J C; Machefert, F P; Rougé, A; Rumpf, M; Valassi, Andrea; Videau, H L; Focardi, E; Parrini, G; Zachariadou, K; Cavanaugh, R J; Corden, M; Georgiopoulos, C H; Hühn, T; Jaffe, D E; Antonelli, A; Bencivenni, G; Bologna, G; Bossi, F; Campana, P; Capon, G; Casper, David William; Chiarella, V; Felici, G; Laurelli, P; Mannocchi, G; Murtas, F; Murtas, G P; Passalacqua, L; Pepé-Altarelli, M; Curtis, L; Dorris, S J; Halley, A W; Knowles, I G; Lynch, J G; O'Shea, V; Raine, C; Scarr, J M; Smith, K; Teixeira-Dias, P; Thompson, A S; Thomson, E; Thomson, F; Turnbull, R M; Geweniger, C; Graefe, G; Hanke, P; Hansper, G; Hepp, V; Kluge, E E; Putzer, A; Schmidt, M; Sommer, J; Tittel, K; Werner, S; Wunsch, M; Beuselinck, R; Binnie, David M; Cameron, W; Dornan, Peter J; Girone, M; Goodsir, S M; Martin, E B; Morawitz, P; Moutoussi, A; Nash, J; Sedgbeer, J K; Spagnolo, P; Stacey, A M; Williams, M D; Ghete, V M; Girtler, P; Kuhn, D; Rudolph, G; Betteridge, A P; Bowdery, C K; Colrain, P; Crawford, G; Finch, A J; Foster, F; Hughes, G; Jones, R W L; Sloan, Terence; Whelan, E P; Williams, M I; Hoffmann, C; Jakobs, K; Kleinknecht, K; Quast, G; Renk, B; Rohne, E; Sander, H G; Van Gemmeren, P; Zeitnitz, C; Aubert, Jean-Jacques; Benchouk, C; Bonissent, A; Bujosa, G; Calvet, D; Carr, J; Coyle, P; Diaconu, C A; Konstantinidis, N P; Leroy, O; Motsch, F; Payre, P; Talby, M; Sadouki, A; Thulasidas, M; Tilquin, A; Trabelsi, K; Aleppo, M; Ragusa, F; Berlich, R; Blum, Walter; Büscher, V; Dietl, H; Ganis, G; Gotzhein, C; Kroha, H; Lütjens, G; Lutz, Gerhard; Männer, W; Moser, H G; Richter, R H; Rosado-Schlosser, A; Schael, S; Settles, Ronald; Seywerd, H C J; Saint-Denis, R; Stenzel, H; Wiedenmann, W; Wolf, G; Boucrot, J; Callot, O; Chen, S; Cordier, A; Davier, M; Duflot, L; Grivaz, J F; Heusse, P; Höcker, A; Jacholkowska, A; Jacquet, M; Kim, D W; Le Diberder, F R; Lefrançois, J; Lutz, A M; Nikolic, I A; Schune, M H; Serin, L; Simion, S; Tournefier, E; Veillet, J J; Videau, I; Zerwas, D; Azzurri, P; Bagliesi, G; Bettarini, S; Bozzi, C; Calderini, G; Ciulli, V; Dell'Orso, R; Fantechi, R; Ferrante, I; Giassi, A; Gregorio, A; Ligabue, F; Lusiani, A; Marrocchesi, P S; Messineo, A; Palla, Fabrizio; Sanguinetti, G; Sciabà, A; Steinberger, Jack; Tenchini, Roberto; Vannini, C; Venturi, A; Verdini, P G; Blair, G A; Bryant, L M; Chambers, J T; Gao, Y; Green, M G; Medcalf, T; Perrodo, P; Strong, J A; Von Wimmersperg-Töller, J H; Botterill, David R; Clifft, R W; Edgecock, T R; Haywood, S; Maley, P; Norton, P R; Thompson, J C; Wright, A E; Bloch-Devaux, B; Colas, P; Kozanecki, Witold; Lançon, E; Lemaire, M C; Locci, E; Pérez, P; Rander, J; Renardy, J F; Rosowsky, A; Roussarie, A; Schuller, J P; Schwindling, J; Trabelsi, A; Vallage, B; Black, S N; Dann, J H; Kim, H Y; Litke, A M; McNeil, M A; Taylor, G; Booth, C N; Boswell, R; Brew, C A J; Cartwright, S L; Combley, F; Kelly, M S; Lehto, M H; Newton, W M; Reeve, J; Thompson, L F; Affholderbach, K; Böhrer, A; Brandt, S; Cowan, G D; Foss, J; Grupen, Claus; Saraiva, P; Smolik, L; Stephan, F; Apollonio, M; Bosisio, L; Della Marina, R; Giannini, G; Gobbo, B; Musolino, G; Pütz, J; Rothberg, J E; Wasserbaech, S R; Williams, R W; Armstrong, S R; Charles, E; Elmer, P; Ferguson, D P S; González, S; Greening, T C; Hayes, O J; Hu, H; Jin, S; McNamara, P A; Nachtman, J M; Nielsen, J; Orejudos, W; Pan, Y B; Saadi, Y; Scott, I J; Walsh, J; Wu Sau Lan; Wu, X; Yamartino, J M; Zobernig, G

    1997-01-01

    The data recorded by the ALEPH experiment at LEP at centre-of-mass energies of 161 GeV and 172 GeV were analysed to search for sleptons, the supersymmetric partners of leptons. No evidence for the production of these particles was found. The number of candidates observed is consistent with the background expected from four-fermion processes and gammagamma-interactions. Improved mass limits at 95% C.L. are reported.

  15. Search for sleptons in e+e- collisions at centre-of-mass energies of 161 GeV and 172 GeV

    Science.gov (United States)

    Barate, R.; Buskulic, D.; Decamp, D.; Ghez, P.; Goy, C.; Lees, J.-P.; Lucotte, A.; Minard, M.-N.; Nief, J.-Y.; Pietrzyk, B.; Casado, M. P.; Chmeissani, M.; Comas, P.; Crespo, J. M.; Delfino, M.; Fernandez, E.; Fernandez-Bosman, M.; Garrido, Ll.; Juste, A.; Martinez, M.; Miquel, R.; Mir, Ll. M.; Orteu, S.; Padilla, C.; Park, I. C.; Pascual, A.; Perlas, J. A.; Riu, I.; Sanchez, F.; Teubert, F.; Colaleo, A.; Creanza, D.; de Palma, M.; Gelao, G.; Iaselli, G.; Maggi, G.; Maggi, M.; Marinelli, N.; Nuzzo, S.; Ranieri, A.; Raso, G.; Ruggieri, F.; Selvaggi, G.; Silvestris, L.; Tempesta, P.; Tricomi, A.; Zito, G.; Huang, X.; Lin, J.; Ouyang, Q.; Wang, T.; Xie, Y.; Xu, R.; Xue, S.; Zhang, J.; Zhang, L.; Zhao, W.; Abbaneo, D.; Alemany, R.; Bazarko, A. O.; Becker, U.; Bright-Thomas, P.; Cattaneo, M.; Cerutti, F.; Dissertori, G.; Drevermann, H.; Forty, R. W.; Frank, M.; Hagelberg, R.; Hansen, J. B.; Harvey, J.; Janot, P.; Jost, B.; Kneringer, E.; Knobloch, J.; Lehraus, I.; Lutters, G.; Mato, P.; Minten, A.; Moneta, L.; Pacheco, A.; Pusztaszeri, J.-F.; Ranjard, F.; Rizzo, G.; Rolandi, L.; Rousseau, D.; Schlatter, D.; Schmitt, M.; Schneider, O.; Tejessy, W.; Tomalin, I. R.; Wachsmuth, H.; Wagner, A.; Ajaltouni, Z.; Barrès, A.; Boyer, C.; Falvard, A.; Ferdi, C.; Gay, P.; Guicheney, C.; Henrard, P.; Jousset, J.; Michel, B.; Monteil, S.; Montret, J.-C.; Pallin, D.; Perret, P.; Podlyski, F.; Proriol, J.; Rosnet, P.; Rossignol, J.-M.; Fearnley, T.; Hansen, J. D.; Hansen, J. R.; Hansen, P. H.; Nilsson, B. S.; Rensch, B.; Wäänänen, A.; Daskalakis, G.; Kyriakis, A.; Markou, C.; Simopoulou, E.; Vayaki, A.; Blondel, A.; Brient, J. C.; Machefert, F.; Rougé, A.; Rumpf, M.; Valassi, A.; Videau, H.; Focardi, E.; Parrini, G.; Zachariadou, K.; Cavanaugh, R.; Corden, M.; Georgiopoulos, C.; Huehn, T.; Jaffe, D. E.; Antonelli, A.; Bencivenni, G.; Bologna, G.; Bossi, F.; Campana, P.; Capon, G.; Casper, D.; Chiarella, V.; Felici, G.; Laurelli, P.; Mannocchi, G.; Murtas, F.; Murtas, G. P.; Passalacqua, L.; Pepe-Altarelli, M.; Curtis, L.; Dorris, S. J.; Halley, A. W.; Knowles, I. G.; Lynch, J. G.; O'Shea, V.; Raine, C.; Scarr, J. M.; Smith, K.; Teixeira-Dias, P.; Thompson, A. S.; Thomson, E.; Thomson, F.; Turnbull, R. M.; Geweniger, C.; Graefe, G.; Hanke, P.; Hansper, G.; Hepp, V.; Kluge, E. E.; Putzer, A.; Schmidt, M.; Sommer, J.; Tittel, K.; Werner, S.; Wunsch, M.; Beuselinck, R.; Binnie, D. M.; Cameron, W.; Dornan, P. J.; Girone, M.; Goodsir, S.; Martin, E. B.; Morawitz, P.; Moutoussi, A.; Nash, J.; Sedgbeer, J. K.; Spagnolo, P.; Stacey, A. M.; Williams, M. D.; Ghete, V. M.; Girtler, P.; Kuhn, D.; Rudolph, G.; Betteridge, A. P.; Bowdery, C. K.; Colrain, P.; Crawford, G.; Finch, A. J.; Foster, F.; Hughes, G.; Jones, R. W.; Sloan, T.; Whelan, E. P.; Williams, M. I.; Hoffmann, C.; Jakobs, K.; Kleinknecht, K.; Quast, G.; Renk, B.; Rohne, E.; Sander, H.-G.; van Gemmeren, P.; Zeitnitz, C.; Aubert, J. J.; Benchouk, C.; Bonissent, A.; Bujosa, G.; Calvet, D.; Carr, J.; Coyle, P.; Diaconu, C.; Konstantinidis, N.; Leroy, O.; Motsch, F.; Payre, P.; Talby, M.; Sadouki, A.; Thulasidas, M.; Tilquin, A.; Trabelsi, K.; Aleppo, M.; Ragusa, F.; Berlich, R.; Blum, W.; Büscher, V.; Dietl, H.; Ganis, G.; Gotzhein, C.; Kroha, H.; Lütjens, G.; Lutz, G.; Männer, W.; Moser, H.-G.; Richter, R.; Rosado-Schlosser, A.; Schael, S.; Settles, R.; Seywerd, H.; St. Denis, R.; Stenzel, H.; Wiedenmann, W.; Wolf, G.; Boucrot, J.; Callot, O.; Chen, S.; Cordier, A.; Davier, M.; Duflot, L.; Grivaz, J.-F.; Heusse, Ph.; Höcker, A.; Jacholkowska, A.; Jacquet, M.; Kim, D. W.; Le Diberder, F.; Lefrançois, J.; Lutz, A.-M.; Nikolic, I.; Schune, M.-H.; Serin, L.; Simion, S.; Tournefier, E.; Veillet, J.-J.; Videau, I.; Zerwas, D.; Azzurri, P.; Bagliesi, G.; Bettarini, S.; Bozzi, C.; Calderini, G.; Ciulli, V.; dell'Orso, R.; Fantechi, R.; Ferrante, I.; Giassi, A.; Gregorio, A.; Ligabue, F.; Lusiani, A.; Marrocchesi, P. S.; Messineo, A.; Palla, F.; Sanguinetti, G.; Sciabà, A.; Steinberger, J.; Tenchini, R.; Vannini, C.; Venturi, A.; Verdini, P. G.; Blair, G. A.; Bryant, L. M.; Chambers, J. T.; Gao, Y.; Green, M. G.; Medcalf, T.; Perrodo, P.; Strong, J. A.; von Wimmersperg-Toeller, J. H.; Botterill, D. R.; Clifft, R. W.; Edgecock, T. R.; Haywood, S.; Maley, P.; Norton, P. R.; Thompson, J. C.; Wright, A. E.; Bloch-Devaux, B.; Colas, P.; Fabbro, B.; Kozanecki, W.; Lançon, E.; Lemaire, M. C.; Locci, E.; Perez, P.; Rander, J.; Renardy, J.-F.; Rosowsky, A.; Roussarie, A.; Schuller, J.-P.; Schwindling, J.; Trabelsi, A.; Vallage, B.; Black, S. N.; Dann, J. H.; Kim, H. Y.; Litke, A. M.; McNeil, M. A.; Taylor, G.; Booth, C. N.; Boswell, R.; Brew, C. A. J.; Cartwright, S.; Combley, F.; Kelly, M. S.; Lehto, M.; Newton, W. M.; Reeve, J.; Thompson, L. F.; Affholderbach, K.; Böhrer, A.; Brandt, S.; Cowan, G.; Foss, J.; Grupen, C.; Saraiva, P.; Smolik, L.; Stephan, F.; Apollonio, M.; Bosisio, L.; della Marina, R.; Giannini, G.; Gobbo, B.; Musolino, G.; Putz, J.; Rothberg, J.; Wasserbaech, S.; Williams, R. W.; Armstrong, S. R.; Charles, E.; Elmer, P.; Ferguson, D. P. S.; González, S.; Greening, T. C.; Hayes, O. J.; Hu, H.; Jin, S.; McNamara, P. A.; Nachtman, J. M.; Nielsen, J.; Orejudos, W.; Pan, Y. B.; Saadi, Y.; Scott, I. J.; Walsh, J.; Sau, Lan Wu; Wu, X.; Yamartino, J. M.; Zobernig, G.

    1997-02-01

    The data recorded by the ALEPH experiment at LEP at centre-of-mass energies of 161 GeV and 172 GeV were analysed to search for sleptons, the supersymmetric partners of leptons. No evidence for the production of these particles was found. The number of candidates observed is consistent with the background expected from four-fermion processes and yy-interactions. Improved mass limits at 95% C.L. are reported.

  16. Ge/Si(001) heterostructures with dense arrays of Ge quantum dots: morphology, defects, photo-emf spectra and terahertz conductivity.

    Science.gov (United States)

    Yuryev, Vladimir A; Arapkina, Larisa V; Storozhevykh, Mikhail S; Chapnin, Valery A; Chizh, Kirill V; Uvarov, Oleg V; Kalinushkin, Victor P; Zhukova, Elena S; Prokhorov, Anatoly S; Spektor, Igor E; Gorshunov, Boris P

    2012-07-23

    : Issues of Ge hut cluster array formation and growth at low temperatures on the Ge/Si(001) wetting layer are discussed on the basis of explorations performed by high resolution STM and in-situ RHEED. Dynamics of the RHEED patterns in the process of Ge hut array formation is investigated at low and high temperatures of Ge deposition. Different dynamics of RHEED patterns during the deposition of Ge atoms in different growth modes is observed, which reflects the difference in adatom mobility and their 'condensation' fluxes from Ge 2D gas on the surface for different modes, which in turn control the nucleation rates and densities of Ge clusters. Data of HRTEM studies of multilayer Ge/Si heterostructures are presented with the focus on low-temperature formation of perfect films.Heteroepitaxial Si p-i-n-diodes with multilayer stacks of Ge/Si(001) quantum dot dense arrays built in intrinsic domains have been investigated and found to exhibit the photo-emf in a wide spectral range from 0.8 to 5 μm. An effect of wide-band irradiation by infrared light on the photo-emf spectra has been observed. Photo-emf in different spectral ranges has been found to be differently affected by the wide-band irradiation. A significant increase in photo-emf is observed in the fundamental absorption range under the wide-band irradiation. The observed phenomena are explained in terms of positive and neutral charge states of the quantum dot layers and the Coulomb potential of the quantum dot ensemble. A new design of quantum dot infrared photodetectors is proposed.By using a coherent source spectrometer, first measurements of terahertz dynamical conductivity (absorptivity) spectra of Ge/Si(001) heterostructures were performed at frequencies ranged from 0.3 to 1.2 THz in the temperature interval from 300 to 5 K. The effective dynamical conductivity of the heterostructures with Ge quantum dots has been discovered to be significantly higher than that of the structure with the same amount of bulk

  17. The role of SiGe buffer in growth and relaxation of Ge on free-standing Si(001) nano-pillars.

    Science.gov (United States)

    Zaumseil, P; Kozlowski, G; Schubert, M A; Yamamoto, Y; Bauer, J; Schülli, T U; Tillack, B; Schroeder, T

    2012-09-07

    We study the growth and relaxation processes of Ge nano-clusters selectively grown by chemical vapor deposition on free-standing 90 nm wide Si(001) nano-pillars with a thin Si(0.23)Ge(0.77) buffer layer. We found that the dome-shaped SiGe layer with a height of about 28 nm as well as the Ge dot deposited on top of it partially relaxes, mainly by elastic lattice bending. The Si nano-pillar shows a clear compliance behavior-an elastic response of the substrate on the growing film-with the tensile strained top part of the pillar. Additional annealing at 800 °C leads to the generation of misfit dislocation and reduces the compliance effect significantly. This example demonstrates that despite the compressive strain generated due to the surrounding SiO(2) growth mask it is possible to realize an overall tensile strain in the Si nano-pillar and following a compliant substrate effect by using a SiGe buffer layer. We further show that the SiGe buffer is able to improve the structural quality of the Ge nano-dot.

  18. Selective growth of Ge nanowires by low-temperature thermal evaporation.

    Science.gov (United States)

    Sutter, Eli; Ozturk, Birol; Sutter, Peter

    2008-10-29

    High-quality single-crystalline Ge nanowires with electrical properties comparable to those of bulk Ge have been synthesized by vapor-liquid-solid growth using Au growth seeds on SiO(2)/Si(100) substrates and evaporation from solid Ge powder in a low-temperature process at crucible temperatures down to 700 °C. High nanowire growth rates at these low source temperatures have been identified as being due to sublimation of GeO from substantial amounts of GeO(2) on the powder. The Ge nanowire synthesis from GeO is highly selective at our substrate temperatures (420-500 °C), i.e., occurs only on Au vapor-liquid-solid growth seeds. For growth of nanowires of 10-20 µm length on Au particles, an upper bound of 0.5 nm Ge deposition was determined in areas of bare SiO(2)/Si substrate without Au nanoparticles.

  19. From plastic to elastic stress relaxation in highly mismatched SiGe/Si heterostructures

    International Nuclear Information System (INIS)

    Isa, Fabio; Salvalaglio, Marco; Dasilva, Yadira Arroyo Rojas; Jung, Arik; Isella, Giovanni; Erni, Rolf; Niedermann, Philippe; Gröning, Pierangelo; Montalenti, Francesco; Känel, Hans von

    2016-01-01

    We present a detailed experimental and theoretical analysis of the epitaxial stress relaxation process in micro-structured compositionally graded alloys. We focus on the pivotal SiGe/Si(001) system employing patterned Si substrates at the micrometre-size scale to address the distribution of threading and misfit dislocations within the heterostructures. SiGe alloys with linearly increasing Ge content were deposited by low energy plasma enhanced chemical vapour deposition resulting in isolated, tens of micrometre tall 3D crystals. We demonstrate that complete elastic relaxation is achieved by appropriate choice of the Ge compositional grading rate and Si pillar width. We investigate the nature and distribution of dislocations along the [001] growth direction in SiGe crystals by transmission electron microscopy, chemical defect etching and etch pit counting. We show that for 3 μm wide Si pillars and a Ge grading rate of 1.5% μm −1 , only misfit dislocations are present while their fraction is reduced for higher Ge grading rates and larger structures due to dislocation interactions. The experimental results are interpreted with the help of theoretical calculations based on linear elasticity theory describing the competition between purely elastic and plastic stress relaxation with increasing crystal width and Ge compositional grading rate.

  20. Whispering Gallery Mode Resonances from Ge Micro-Disks on Suspended Beams

    Directory of Open Access Journals (Sweden)

    Abdelrahman Zaher Al-Attili

    2015-05-01

    Full Text Available Ge is considered to be one of the most promising materials for realizing full monolithic integration of a light source on a silicon (Si photonic chip. Tensile-strain is required to convert Ge into an optical gain material and to reduce the pumping required for population inversion. Several methods of strain application to Ge are proposed in literature, of which the use of free-standing beams fabricated by micro-electro-mechanical systems (MEMS processes are capable of delivering very high strain values. However, it is challenging to make an optical cavity within free-standing Ge beams, and here, we demonstrate the fabrication of a simple cavity while imposing tensile strain by suspension using Ge-On-Insulator (GOI wafers. Ge micro-disks are made on top of suspended SiO$_{2}$ beams by partially removing the supporting Si substrate. According to Raman spectroscopy, a slight tensile strain was applied to the Ge disks through the bending of the SiO2 beams. Whispering-Gallery-Mode (WGM resonances were observed from a disk with a diameter of 3um, consistent with the finite-domain time-difference simulations. The quality (Q factor was 192, and upon increasing the pumping power, the Q-factor was degraded due to the red-shift of Ge direct-gap absorption edge caused by heating.

  1. Photoluminescent characteristics of ion beam synthesized Ge nanoparticles in thermally grown SiO2 films

    International Nuclear Information System (INIS)

    Yu, C.F.; Chao, D.S.; Chen, Y.-F.; Liang, J.H.

    2013-01-01

    Prospects of developing into numerous silicon-based optoelectronic applications have prompted many studies on the optical properties of Ge nanoparticles within a silicon oxide (SiO 2 ) matrix. Even with such abundant studies, the fundamental mechanism underlying the Ge nanoparticle-induced photoluminescence (PL) is still an open question. In order to elucidate the mechanism, we dedicate this study to investigating the correlation between the PL properties and microstructure of the Ge nanoparticles synthesized in thermally grown SiO 2 films. Our spectral data show that the peak position, at ∼3.1 eV or 400 nm, of the PL band arising from the Ge nanoparticles was essentially unchanged under different Ge implantation fluences and the temperatures of the following annealing process, whereas the sample preparation parameters modified or even fluctuated (in the case of the annealing temperature) the peak intensity considerably. Given the microscopically observed correlation between the nanoparticle structure and the sample preparation parameters, this phenomenon is consistent with the mechanism in which the oxygen-deficiency-related defects in the Ge/SiO 2 interface act as the major luminescence centers; this mechanism also successfully explains the peak intensity fluctuation with the annealing temperature. Moreover, our FTIR data indicate the formation of GeO x upon ion implantation. Since decreasing of the oxygen-related defects by the GeO x formation is expected to be correlated with the annealing temperature, presence of the GeO x renders further experimental support to the oxygen defect mechanism. This understanding may assist the designing of the manufacturing process to optimize the Ge nanoparticle-based PL materials for different technological applications

  2. Improvement of photoluminescence from Ge layer with patterned Si3N4 stressors

    International Nuclear Information System (INIS)

    Oda, Katsuya; Okumura, Tadashi; Tani, Kazuki; Saito, Shin-ichi; Ido, Tatemi

    2014-01-01

    Lattice strain applied by patterned Si 3 N 4 stressors in order to improve the optical properties of Ge layers directly grown on a Si substrate was investigated. Patterned Si 3 N 4 stressors were fabricated by various methods and their effects on the strain and photoluminescence were studied. Although we found that when the stressor was fabricated by thermal chemical vapor deposition (CVD), the Ge waveguide was tensilely and compressively strained in the edge and center positions, respectively, and photoluminescence (PL) could be improved by decreasing the width of the waveguide, the crystallinity of the Ge waveguide was degraded by the thermal impact of the deposition process. Low-temperature methods were therefore used to make the patterned stressors. The tensile strain of the Ge layer increased from 0.14% to 0.2% when the stressor was grown by plasma enhanced CVD at 350 °C, but the effects of the increased tensile strain could not be confirmed because the Si 3 N 4 layer was unstable when irradiated with the excitation light used in photoluminescence measurements. Si 3 N 4 stressors grown by inductively coupled plasma CVD at room temperature increased the tensile strain of the Ge layer up to 0.4%, thus red-shifting the PL peak and obviously increasing the PL intensity. These results indicate that the Si 3 N 4 stressors fabricated by the room-temperature process efficiently improve the performance of Ge light-emitting devices. - Highlights: • Ge layers were directly grown on a Si substrate by low-temperature epitaxial growth. • Si 3 N 4 stressors were fabricated on the Ge layers by various methods. • Tensile strain of the Ge layers was improved by the Si 3 N 4 stressors. • Photoluminescence (PL) intensity was increased with the Si 3 N 4 stressors. • Red-shift of the PL spectra was observed from the tensile strained Ge layers

  3. Formation, structure, and phonon confinement effect of nanocrystalline Si1-xGex in SiO2-Si-Ge cosputtered films

    International Nuclear Information System (INIS)

    Yang, Y.M.; Wu, X.L.; Siu, G.G.; Huang, G.S.; Shen, J.C.; Hu, D.S.

    2004-01-01

    Using magnetron cosputtering of SiO 2 , Ge, and Si targets, Si-based SiO 2 :Ge:Si films were fabricated for exploring the influence of Si target proportion (P Si ) and annealing temperature (Ta) on formation, local structure, and phonon properties of nanocrystalline Si 1-x Ge x (nc-Si 1-x Ge x ). At low P Si and Ta higher than 800 deg. C, no nc-Si 1-x Ge x but a kind of composite nanocrystal consisting of a Ge core, GeSi shell, and amorphous Si outer shell is formed in the SiO 2 matrix. At moderate P Si , nc-Si 1-x Ge x begins to be formed at Ta=800 deg. C and coexists with nc-Ge at Ta=1100 deg. C. At high P Si , it was disclosed that both optical phonon frequency and lattice spacing of nc-Si 1-x Ge x increase with raising Ta. The possible origin of this phenomenon is discussed by considering three factors, the phonon confinement, strain effect, and composition variation of nc-Si 1-x Ge x . This work will be helpful in understanding the growth process of ternary GeSiO films and beneficial to further investigations on optical properties of nc-Ge 1-x Si x in the ternary matrix

  4. Room Temperature Ferromagnetic Mn:Ge(001

    Directory of Open Access Journals (Sweden)

    George Adrian Lungu

    2013-12-01

    Full Text Available We report the synthesis of a room temperature ferromagnetic Mn-Ge system obtained by simple deposition of manganese on Ge(001, heated at relatively high temperature (starting with 250 °C. The samples were characterized by low energy electron diffraction (LEED, scanning tunneling microscopy (STM, high resolution transmission electron microscopy (HRTEM, X-ray photoelectron spectroscopy (XPS, superconducting quantum interference device (SQUID, and magneto-optical Kerr effect (MOKE. Samples deposited at relatively elevated temperature (350 °C exhibited the formation of ~5–8 nm diameter Mn5Ge3 and Mn11Ge8 agglomerates by HRTEM, while XPS identified at least two Mn-containing phases: the agglomerates, together with a Ge-rich MnGe~2.5 phase, or manganese diluted into the Ge(001 crystal. LEED revealed the persistence of long range order after a relatively high amount of Mn (100 nm deposited on the single crystal substrate. STM probed the existence of dimer rows on the surface, slightly elongated as compared with Ge–Ge dimers on Ge(001. The films exhibited a clear ferromagnetism at room temperature, opening the possibility of forming a magnetic phase behind a nearly ideally terminated Ge surface, which could find applications in integration of magnetic functionalities on semiconductor bases. SQUID probed the co-existence of a superparamagnetic phase, with one phase which may be attributed to a diluted magnetic semiconductor. The hypothesis that the room temperature ferromagnetic phase might be the one with manganese diluted into the Ge crystal is formulated and discussed.

  5. 7-GeV Advanced Photon Source Conceptual Design Report

    International Nuclear Information System (INIS)

    1987-04-01

    During the past decade, synchrotron radiation emitted by circulating electron beams has come into wide use as a powerful, versatile source of x-rays for probing the structure of matter and for studying various physical processes. Several synchrotron radiation facilities with different designs and characteristics are now in regular operation throughout the world, with recent additions in this country being the 0.8-GeV and 2.5-GeV rings of NSLS at Brookhaven National Laboratory. However, none of the operating facilities has been designed to use a low-emittance, high-energy stored beam, together with modern undulator devices, to produce a large number of hard x-ray beams of extremely high brilliance. This document is a proposal to the Department of Energy to construct and operate high-energy synchrotron radiation facility at Argonne National Laboratory. We have now chosen to set the design energy of this facility at 7.0 GeV, with the capability to operate at up to 7.5 GeV

  6. Improved thermal stability and hole mobilities in a strained-Si/strained-Si1-yGe y/strained-Si heterostructure grown on a relaxed Si1-xGe x buffer

    International Nuclear Information System (INIS)

    Gupta, Saurabh; Lee, Minjoo L.; Isaacson, David M.; Fitzgerald, Eugene A.

    2005-01-01

    A dual channel heterostructure consisting of strained-Si/strained-Si 1-y Ge y on relaxed Si 1-x Ge x (y > x), provides a platform for fabricating metal-oxide-semiconductor field-effect transistors (MOSFETs) with high hole mobilities (μ eff ) which depend directly on Ge concentration and strain in the strained-Si 1-y Ge y layer. Ge out-diffuses from the strained-Si 1-y Ge y layer into relaxed Si 1-x Ge x during high temperature processing, reducing peak Ge concentration and strain in the strained-Si 1-y Ge y layer and degrades hole μ eff in these dual channel heterostructures. A heterostructure consisting of strained-Si/strained-Si 1-y Ge y /strained-Si, referred to as a trilayer heterostructure, grown on relaxed Si 1-x Ge x has much reduced Ge out-flux from the strained-Si 1-y Ge y layer and retains higher μ eff after thermal processing. Improved hole μ eff over similar dual channel heterostructures is also observed in this heterostructure. This could be a result of preventing the hole wavefunction tunneling into the low μ eff relaxed Si 1-x Ge x layer due to the additional valence band offset provided by the underlying strained-Si layer. A diffusion coefficient has been formulated and implemented in a finite difference scheme for predicting the thermal budget of the strained SiGe heterostructures. It shows that the trilayer heterostructures have superior thermal budgets at higher Ge concentrations. Ring-shaped MOSFETs were fabricated on both platforms and subjected to various processing temperatures in order to compare the extent of μ eff reduction with thermal budget. Hole μ eff enhancements are retained to a much higher extent in a trilayer heterostructure after high temperature processing as compared to a dual channel heterostructure. The improved thermal stability and hole μ eff of a trilayer heterostructure makes it an ideal platform for fabricating high μ eff MOSFETs that can be processed over higher temperatures without significant losses in hole

  7. The study on Ge-68 production

    International Nuclear Information System (INIS)

    Yang, Seung Dae; Kim, Sang Wook; Hur, Min Goo

    2009-06-01

    The Ge-68 is a correction source of PET and is used in radiopharmaceuticals synthesis. This project is mainly aimed to produce the Ge-68. Based on this project results, the local Ge-68 production can be possible and the revitalization of the radioisotope utilization research areas can be accomplished. The characteristics of the Ge-68 and Ga-68 are obtained and analyzed. The production conditions are also developed, and the domestic and overseas status of the art are considered. The stacked foil target is designed using Al disc and dried Ga 2 O 3 powder, and the irradiation target is also designed. The cross section of the nat. Ga(p,xn) 68 Ge reaction is obtained using the developed target. The separation experiment of cold Ge/Ga in the H 2 SO 4 -HCl solution are carried out as a simulation experiment of the radioactive Ge/Ga sources. The separation of Ge/Ga by liquid extraction of CCl 4 in 8M HCl is also accomplished. And the synthesis experiment of the Hematophorphyrin-Ga complex is performed

  8. Ultra-smooth epitaxial Ge grown on Si(001) utilizing a thin C-doped Ge buffer layer

    KAUST Repository

    Mantey, J.; Hsu, W.; James, J.; Onyegam, E. U.; Guchhait, S.; Banerjee, S. K.

    2013-01-01

    Here, we present work on epitaxial Ge films grown on a thin buffer layer of C doped Ge (Ge:C). The growth rate of Ge:C is found to slow over time and is thus unsuitable for thick (>20 nm) layers. We demonstrate Ge films from 10 nm to >150 nm

  9. Growth and characterization of isotopically enriched 70Ge and 74Ge single crystals

    International Nuclear Information System (INIS)

    Itoh, K.

    1992-10-01

    Isotopically enriched 70 Ge and 74 Ge single crystals were successfully gown by a newly developed vertical Bridgman method. The system allows us to reliably grow high purity Ge single crystals of approximately 1 cm 3 volume. To our knowledge, we have grown the first 70 Ge single crystal. The electrically active chemical impurity concentration for both crystals was found to be ∼2 x cm -3 which is two order of magnitude better that of 74 Ge crystals previously grown by two different groups. Isotopic enrichment of the 70 Ge and the 74 Ge crystals is 96.3% and 96.8%, respectively. The residual chemical impurities present in both crystals were identified as phosphorus, copper, aluminum, and indium. A wide variety of experiments which take advantage of the isotopic purity of our crystals are discussed

  10. Reduction of 68Ge activity containing liquid waste from 68Ga PET chemistry in nuclear medicine and radiopharmacy by solidification.

    Science.gov (United States)

    de Blois, Erik; Chan, Ho Sze; Roy, Kamalika; Krenning, Eric P; Breeman, Wouter A P

    PET with 68 Ga from the TiO 2 - or SnO 2 - based 68 Ge/ 68 Ga generators is of increasing interest for PET imaging in nuclear medicine. In general, radionuclidic purity ( 68 Ge vs. 68 Ga activity) of the eluate of these generators varies between 0.01 and 0.001%. Liquid waste containing low amounts of 68 Ge activity is produced by eluting the 68 Ge/ 68 Ga generators and residues from PET chemistry. Since clearance level of 68 Ge activity in waste may not exceed 10 Bq/g, as stated by European Directive 96/29/EURATOM, our purpose was to reduce 68 Ge activity in solution from >10 kBq/g to <10 Bq/g; which implies the solution can be discarded as regular waste. Most efficient method to reduce the 68 Ge activity is by sorption of TiO 2 or Fe 2 O 3 and subsequent centrifugation. The required 10 Bq per mL level of 68 Ge activity in waste was reached by Fe 2 O 3 logarithmically, whereas with TiO 2 asymptotically. The procedure with Fe 2 O 3 eliminates ≥90% of the 68 Ge activity per treatment. Eventually, to simplify the processing a recirculation system was used to investigate 68 Ge activity sorption on TiO 2 , Fe 2 O 3 or Zeolite. Zeolite was introduced for its high sorption at low pH, therefore 68 Ge activity containing waste could directly be used without further interventions. 68 Ge activity containing liquid waste at different HCl concentrations (0.05-1.0 M HCl), was recirculated at 1 mL/min. With Zeolite in the recirculation system, 68 Ge activity showed highest sorption.

  11. Investigation of the diffractive reaction p + N → [Σ+K0] + N at the proton energy of Ep = 70 GeV and observation of the decay process X(2000) → Σ+K0

    International Nuclear Information System (INIS)

    Vavilov, D.V.; Viktorov, V.A.; Golovkin, S.V.; Kozhevnikov, A.P.; Kubarovsky, V.P.; Kurshetsov, V.F.; Landsberg, L.G.; Molchanov, V.V.; Mukhin, V.A.; Petrenko, S.V.; Kolganov, V.Z.; Lomkatsi, G.S.; Nilov, A.F.; Smolyankin, V.T.

    2000-01-01

    The diffractive reaction p + N → [Σ + K 0 ] + N induced by 70-GeV protons is investigated at the SPHINX facility. The measured mass spectrum of the Σ + K 0 system originating from this reaction shows a resonance structure with a mass of M = 1995 ± 18 MeV and a width of Γ = 90 ± 32 MeV. The cross section for the formation of this structure is found to be σ = 182 ± 38 nb per target nucleon. These data comply well with the results that we obtained previously in studying the reaction p + N → [Σ 0 K + ] + N, where we observed the formation of the X(2000) → Σ 0 K + state, a candidate for an exotic baryon with hidden strangeness. The measured ratio R of the two branching fractions, R = Br[X(2000) → Σ + K 0 ]/Br[X(2000) → Σ 0 K + ] =1.91 ± 0.38, is consistent with the value of R = 2 expected for an isospin-1/2 baryon

  12. Effect of Ge nanocluster assembly self-organization at pulsed irradiation by low-energy ions during heteroepitaxy on Si

    CERN Document Server

    Dvurechenskij, A V; Smagina, Z V

    2001-01-01

    Using the method of scanning microscopy one studied experimentally size distribution of Ge clusters formed in course of experiments of two types at Ge heteroepitaxy on Si(111): regular process of molecular-beam epitaxy (MBE); pulse irradiation by approx = 200 eV energy Ge ions. The experiments were conducted at 350 deg C temperature. Pulse irradiation by an ion beam during heteroepitaxy was detected to result in reduction of the average size of Ge clusters, in compacting of their density and in reduction of mean square deviation from the average value in contrast to similar values in experiments devoted to regular MBE

  13. Elastic p-4He scattering near 1 GeV

    International Nuclear Information System (INIS)

    Wallace, S.J.; Alexander, Y.

    1977-02-01

    New 1.029 GeV p- 4 He data from an Argonne-UCLA-Minnesota collaboration are in excellent agreement with existing multiple diffraction theory predictions. The theoretical calculation includes spin and isospin dependence of the Δ intermediate state process that fills the first diffraction minimum. The recently normalized Saclay data and the older Brookhaven data disagree with our calculation and the new data

  14. Numerical simulation of microstructure of the GeSi alloy

    Energy Technology Data Exchange (ETDEWEB)

    Rasin, I.

    2006-09-08

    The goal of this work is to investigate pattern formation processes on the solid-liquid interface during the crystal growth of GeSi. GeSi crystals with cellular structure have great potential for applications in -ray and neutron optics. The interface patterns induce small quasi-periodic distortions of the microstructure called mosaicity. Existence and properties of this mosaicity are important for the application of the crystals. The properties depend on many factors; this dependence, is currently not known even not qualitatively. A better understanding of the physics near the crystal surface is therefore required, in order to optimise the growth process. There are three main physical processes in this system: phase-transition, diffusion and melt flow. Every process is described by its own set of equations. Finite difference methods and lattice kinetic methods are taken for solving these governing equations. We have developed a modification of the kinetic methods for the advectiondiffusion and extended this method for simulations of non-linear reaction diffusion equations. The phase-field method was chosen as a tool for describing the phase-transition. There are numerous works applied for different metallic alloys. An attempt to apply the method directly to simulation GeSi crystal growth showed that this method is unstable. This instability has not been observed in previous works due to the much smaller scale of simulations. We introduced a modified phase-field scheme, which enables to simulate pattern formation with the scale observed in experiment. A flow in the melt was taken in to account in the numerical model. The developed numerical model allows us to investigate pattern formation in GeSi crystals. Modelling shows that the flow near the crystal surface has impact on the patterns. The obtained patterns reproduce qualitatively and in some cases quantitatively the experimental results. (orig.)

  15. Inclusive phi-mesion production in 93 and 63 GeV/c hadron interactions

    International Nuclear Information System (INIS)

    Deurzen, P. van.

    1982-01-01

    In this thesis the measurement and analysis is described of the inclusive reaction hadron + proton → phi + anything at 93 and 63 GeV/c incident momentum. Data at 93 GeV/c were obtained for both negative and positive beam polarity and at 63 GeV/c for negative polarity only. A total of 2.5 million triggers were taken which after processing resulted in 11,822 phi-events. The aim of the experiment was to get a better understanding of the production characteristics of the phi-meson. (Auth.)

  16. Evidence for Kinetic Limitations as a Controlling Factor of Ge Pyramid Formation: a Study of Structural Features of Ge/Si(001) Wetting Layer Formed by Ge Deposition at Room Temperature Followed by Annealing at 600 °C.

    Science.gov (United States)

    Storozhevykh, Mikhail S; Arapkina, Larisa V; Yuryev, Vladimir A

    2015-12-01

    The article presents an experimental study of an issue of whether the formation of arrays of Ge quantum dots on the Si(001) surface is an equilibrium process or it is kinetically controlled. We deposited Ge on Si(001) at the room temperature and explored crystallization of the disordered Ge film as a result of annealing at 600 °C. The experiment has demonstrated that the Ge/Si(001) film formed in the conditions of an isolated system consists of the standard patched wetting layer and large droplike clusters of Ge rather than of huts or domes which appear when a film is grown in a flux of Ge atoms arriving on its surface. We conclude that the growth of the pyramids appearing at temperatures greater than 600 °C is controlled by kinetics rather than thermodynamic equilibrium whereas the wetting layer is an equilibrium structure. Primary 68.37.Ef; 68.55.Ac; 68.65.Hb; 81.07.Ta; 81.16.Dn.

  17. Annealing temperature effect on structure and electrical properties of films formed of Ge nanoparticles in SiO2

    International Nuclear Information System (INIS)

    Stavarache, Ionel; Lepadatu, Ana-Maria; Stoica, Toma; Ciurea, Magdalena Lidia

    2013-01-01

    Ge–SiO 2 films with high Ge/Si atomic ratio of about 1.86 were obtained by co-sputtering of Ge and SiO 2 targets and subsequently annealed at different temperatures between 600 and 1000 °C in a conventional furnace in order to show how the annealing process influences the film morphology concerning the Ge nanocrystal and/or amorphous nanoparticle formation and to study their electrical behaviour. Atomic force microscopy (AFM) imaging, Raman spectroscopy and electrical conductance measurements were performed in order to find out the annealing effect on the film surface morphology, as well as the Ge nanoparticle formation in correlation with the hopping conductivity of the films. AFM images show that the films annealed at 600 and 700 °C present a granular surface with particle height of about 15 nm, while those annealed at higher temperatures have smoother surface. The Raman investigations evidence Ge nanocrystals (including small ones) coexisting with amorphous Ge in the films annealed at 600 °C and show that almost all Ge is crystallized in the films annealed at 700 °C. The annealing at 800 °C disadvantages the Ge nanocrystal formation due to the strong Ge diffusion. This transition in Ge nanocrystals formation process by annealing temperature increase from 700 to 800 °C revealed by AFM and Raman spectroscopy measurements corresponds to a change in the electrical transport mechanism. Thus, in the 700 °C annealed films, the current depends on temperature according to a T −1/2 law which is typical for a tunnelling mechanism between neighbour Ge nanocrystals. In the 800 °C annealed films, the current–temperature characteristic has a T −1/4 dependence showing a hopping mechanism within an electronic band of localized states related to diffused Ge in SiO 2 .

  18. Ion-beam synthesis of Ge{sub x}Si{sub 1-x} strained layers for high speed electronic device applications

    Energy Technology Data Exchange (ETDEWEB)

    Elliman, R.G.; Jiang, H.; Wong, W.C.; Kringhoj, P. [Australian National Univ., Canberra, ACT (Australia)

    1996-12-31

    It is shown that Ge{sub x}S{sub 1-x} strained layers can be fabricated by Ge implantation and solid-phase epitaxy and that the use of these layers can improve the performance of electronic devices. Several materials science issues are addressed, including the effect of Ge on solid-phase-epitaxy, the effect of oxidation on the implanted Ge distribution, and the effect of Ge on the oxidation rate of Si. The process is demonstrated for metal-oxide-semiconductor field-effect-transistors (MOSFETs). 6 refs., 5 figs.

  19. Ion-beam synthesis of Ge{sub x}Si{sub 1-x} strained layers for high speed electronic device applications

    Energy Technology Data Exchange (ETDEWEB)

    Elliman, R G; Jiang, H; Wong, W C; Kringhoj, P [Australian National Univ., Canberra, ACT (Australia)

    1997-12-31

    It is shown that Ge{sub x}S{sub 1-x} strained layers can be fabricated by Ge implantation and solid-phase epitaxy and that the use of these layers can improve the performance of electronic devices. Several materials science issues are addressed, including the effect of Ge on solid-phase-epitaxy, the effect of oxidation on the implanted Ge distribution, and the effect of Ge on the oxidation rate of Si. The process is demonstrated for metal-oxide-semiconductor field-effect-transistors (MOSFETs). 6 refs., 5 figs.

  20. High performance Ω-gated Ge nanowire MOSFET with quasi-metallic source/drain contacts.

    Science.gov (United States)

    Burchhart, T; Zeiner, C; Hyun, Y J; Lugstein, A; Hochleitner, G; Bertagnolli, E

    2010-10-29

    Ge nanowires (NWs) about 2 µm long and 35 nm in diameter are grown heteroepitaxially on Si(111) substrates in a hot wall low-pressure chemical vapor deposition (LP-CVD) system using Au as a catalyst and GeH(4) as precursor. Individual NWs are contacted to Cu pads via e-beam lithography, thermal evaporation and lift-off techniques. Self-aligned and atomically sharp quasi-metallic copper-germanide source/drain contacts are achieved by a thermal activated phase formation process. The Cu(3)Ge segments emerge from the Cu contact pads through axial diffusion of Cu which was controlled in situ by SEM, thus the active channel length of the MOSFET is adjusted without any restrictions from a lithographic process. Finally the conductivity of the channel is enhanced by Ga(+) implantation leading to a high performance Ω-gated Ge-NW MOSFET with saturation currents of a few microamperes.

  1. Nuclear energy outlook: a GE perspective

    International Nuclear Information System (INIS)

    Fuller, J.

    2006-01-01

    Full text: Full text: As one of the world's leading suppliers of power generation and energy delivery technologies, GE Energy provides comprehensive solutions for coal, oil, natural gas and nuclear energy; renewable resources such as wind, solar and biogas, along with other alternative fuels. With the ever increasing demand for energy and pressures to decrease greenhouse gas emissions, global trends indicate a move towards building more base line nuclear generation capacity. As a reliable, cost-competitive option for commercial power generation, nuclear energy also addresses many of the issues the world faces when it comes to the environment. Since developing nuclear reactor technology in the 1950s, GE's Boiling Water Reactor (BWR) technology accounts for more than 90 operating plants in the world today. Building on that success, GE's ABWR design is now the first and only Generation 111 nuclear reactor in operation today. This advanced reactor technology, coupled with current construction experience and a qualified global supply chain, make ESBWR, GE's Generation III+ reactor design, an attractive option for owners considering adding nuclear generation capacity. In pursuit of new technologies, GE has teamed with Silex to develop, commercialize and license third generation laser enrichment technology. By acquiring the exclusive rights to develop and commercialize this technology, GE is positioned to support the anticipated global demands for enriched uranium. At GE, we are continuing to develop imaginative ideas and investing in products that are cost effective, increase productivity, limit greenhouse gas emissions, and improve safety and security for our customers

  2. Oxidation-resistant Ge-doped silicide coating on Cr-Cr2Nb alloys by pack cementation

    International Nuclear Information System (INIS)

    He Yirong

    1997-01-01

    The halide-activated pack cementation process was modified to produce a Ge-doped silicide diffusion coating on Cr-Cr 2 Nb alloys in a single processing step. The morphology and composition of the coating depended both on the pack composition and processing schedule and also on the composition and microstructure of the substrate. Higher Ge content in the pack suppressed the formation of CrSi 2 and reduced the growth kinetics of the coating. Ge was not homogeneously distributed in the coatings. Under cyclic and isothermal oxidation conditions, the Ge-doped silicide coating protected the Cr-Nb alloys from significant oxidation and from pesting by the formation of a Ge-doped silica film. (orig.)

  3. New channeling effects in the radiative emission of 150 GeV electrons in a thin germanium crystal

    International Nuclear Information System (INIS)

    Belkacem, A.; Chevallier, M.; Gaillard, M.J.; Genre, R.; Kirsch, R.; Poizat, J.C.; Remillieux, J.; Bologna, G.; Peigneux, J.P.; Sillou, D.; Spighel, M.; Cue, N.; Kimball, J.C.; Marsh, B.; Sun, C.R.

    1986-01-01

    The orientation dependence of the radiative emission of 150 GeV electrons and positrons incident at small angles with respect to the axial direction of a thin (0.185 mm) Ge crystal has been observed. The processes are well understood, except for channeled electrons, which radiate unexpected high energy photons. (orig.)

  4. Growth of Ferromagnetic Epitaxial Film of Hexagonal FeGe on (111) Ge Surface

    Science.gov (United States)

    Kumar, Dushyant; Joshi, P. C.; Hossain, Z.; Budhani, R. C.

    2014-03-01

    The realization of semiconductors showing ferromagnetic order at easily accessible temperatures has been of interest due to their potential use in spintronic devices where long spin life times are of key interest. We have realized the growth of FeGe thin films on Ge (111) wafers using pulsed laser deposition (PLD). The stoichiometric and single phase FeGe target used in PLD chamber has been made by arc melting. A typical θ-2 θ diffraction spectra performed on 40 nm thick FeGe film suggests the stabilization of β-Ni2In (B82-type) hexagonal phase with an epitaxial orientation of (0001)FeGe ||(111)Ge and [11-20]FeGe ||[-110]Ge. SEM images shows a granular structure with the formation of very large grains of about 100 to 500 nm in lateral dimension. The magnetization vs. temperature data taken from SQUID reveal the TC of ~ 270K. Since, PLD technique makes it easier to stabilize the B82 (Ni2In) hexagonal phase in thin FeGe films, this work opens opportunities to reinvestigate many conflicting results on various properties of the FeGe system.

  5. Ge nitride formation in N-doped amorphous Ge2Sb2Te5

    International Nuclear Information System (INIS)

    Jung, M.-C.; Lee, Y. M.; Kim, H.-D.; Kim, M. G.; Shin, H. J.; Kim, K. H.; Song, S. A.; Jeong, H. S.; Ko, C. H.; Han, M.

    2007-01-01

    The chemical state of N in N-doped amorphous Ge 2 Sb 2 Te 5 (a-GST) samples with 0-14.3 N at. % doping concentrations was investigated by high-resolution x-ray photoelectron spectroscopy (HRXPS) and Ge K-edge x-ray absorption spectroscopy (XAS). HRXPS showed negligible change in the Te 4d and Sb 4d core-level spectra. In the Ge 3d core-level spectra, a Ge nitride (GeN x ) peak developed at the binding energy of 30.2 eV and increased in intensity as the N-doping concentration increased. Generation of GeN x was confirmed by the Ge K-edge absorption spectra. These results indicate that the N atoms bonded with the Ge atoms to form GeN x , rather than bonding with the Te or Sb atoms. It has been suggested that the formation of Ge nitride results in increased resistance and phase-change temperature

  6. Thermal conductivity of sputtered amorphous Ge films

    International Nuclear Information System (INIS)

    Zhan, Tianzhuo; Xu, Yibin; Goto, Masahiro; Tanaka, Yoshihisa; Kato, Ryozo; Sasaki, Michiko; Kagawa, Yutaka

    2014-01-01

    We measured the thermal conductivity of amorphous Ge films prepared by magnetron sputtering. The thermal conductivity was significantly higher than the value predicted by the minimum thermal conductivity model and increased with deposition temperature. We found that variations in sound velocity and Ge film density were not the main factors in the high thermal conductivity. Fast Fourier transform patterns of transmission electron micrographs revealed that short-range order in the Ge films was responsible for their high thermal conductivity. The results provide experimental evidences to understand the underlying nature of the variation of phonon mean free path in amorphous solids

  7. Thermoelectric properties of Cu/Ag doped type-III Ba24Ge100 clathrates

    Science.gov (United States)

    Fu, Jiefei; Su, Xianli; Yan, Yonggao; Liu, Wei; Zhang, Zhengkai; She, Xiaoyu; Uher, Ctirad; Tang, Xinfeng

    2017-09-01

    Type-III Ba24Ge100 clathrates possess low thermal conductivity and high electrical conductivity at room temperature and, as such, have a great potential as thermoelectric materials for power generation. However, the Seebeck coefficient is very low due to the intrinsically high carrier concentration. In this paper, a series of Ba24CuxGe100-x and Ba24AgyGe100-y specimens were prepared by vacuum melting combined with the subsequent spark plasma sintering (SPS) process. Doping Cu or Ag on the Ge site not only suppresses the concentration of electrons but it also decreases the thermal conductivity. In addition, the carrier mobility and the Seebeck coefficient increase due to the decrease in the carrier concentration. Thus, the power factor is greatly improved, leading to an improvement in the dimensionless figure of merit ZT. Cu-doped Ba24Cu6Ge94 reaches the maximum ZT value of about 0.17 at 873 K, while Ag-doped Ba24Ag6Ge94 attains the dimensionless figure of merit ZT of 0.31 at 873 K, more than 2 times higher value compared to un-doped Ba24Ge100.

  8. SiGe derivatization by spontaneous reduction of aryl diazonium salts

    Science.gov (United States)

    Girard, A.; Geneste, F.; Coulon, N.; Cardinaud, C.; Mohammed-Brahim, T.

    2013-10-01

    Germanium semiconductors have interesting properties for FET-based biosensor applications since they possess high surface roughness allowing the immobilization of a high amount of receptors on a small surface area. Since SiGe combined low cost of Si and intrinsic properties of Ge with high mobility carriers, we focused the study on this particularly interesting material. The comparison of the efficiency of a functionalization process involving the spontaneous reduction of diazonium salts is studied on Si(1 0 0), SiGe and Ge semiconductors. XPS analysis of the functionalized surfaces reveals the presence of a covalent grafted layer on all the substrates that was confirmed by AFM. Interestingly, the modified Ge derivatives have still higher surface roughness after derivatization. To support the estimated thickness by XPS, a step measurement of the organic layers is done by AFM or by profilometer technique after a O2 plasma etching of the functionalized layer. This original method is well-adapted to measure the thickness of thin organic films on rough substrates such as germanium. The analyses show a higher chemical grafting on SiGe substrates compared with Si and Ge semiconductors.

  9. Study on ancient Chinese imitated GE ware by INAA and WDXRF

    International Nuclear Information System (INIS)

    Xie Guoxi; Feng Songlin; Feng Xiangqian; Wang Yanqing; Zhu Jihao; Yan Lingtong; Li Yongqiang; Han Hongye

    2007-01-01

    Imitated GE ware was one of the most famous products of Jingdezhen porcelain field in Ming dynasty (AD 1368-1644). The exterior features of its body and glaze are very marvelous. Black foot, purple mouth and crazing glaze are the main features of imitated GE ware. Until now, the key conditions of resulting these features are not clearly identified. In order to find the critical elements for firing these features, instrumental neutron activation analysis (INAA) and wavelength-dispersive X-ray fluorescence (WDXRF) were used to determine the element abundance patterns of imitated GE ware body and glaze. The experimental data was compared with that of imitated Longquan celadon and of Longquan celadon. The analytical results indicated that Fe, Ti and Na were the critical elements. The body of imitated GE ware which contains high Fe and Ti are the basic conditions of firing its black body, black foot and purple mouth. The glaze of imitated GE ware which contains high Na is the main condition of producing its crazing glaze. Na is the critical element which enlarges the difference in expansion coefficients between the glaze and body of imitated GE ware. Furthermore, Zijin soil was added into kaolin to make the body rich in Fe and Ti. And something which was rich in Na was used to produce crazing glaze in the manufacturing process of imitated GE ware

  10. Strain field mapping of dislocations in a Ge/Si heterostructure.

    Directory of Open Access Journals (Sweden)

    Quanlong Liu

    Full Text Available Ge/Si heterostructure with fully strain-relaxed Ge film was grown on a Si (001 substrate by using a two-step process by ultra-high vacuum chemical vapor deposition. The dislocations in the Ge/Si heterostructure were experimentally investigated by high-resolution transmission electron microscopy (HRTEM. The dislocations at the Ge/Si interface were identified to be 90° full-edge dislocations, which are the most efficient way for obtaining a fully relaxed Ge film. The only defect found in the Ge epitaxial film was a 60° dislocation. The nanoscale strain field of the dislocations was mapped by geometric phase analysis technique from the HRTEM image. The strain field around the edge component of the 60° dislocation core was compared with those of the Peierls-Nabarro and Foreman dislocation models. Comparison results show that the Foreman model with a = 1.5 can describe appropriately the strain field around the edge component of a 60° dislocation core in a relaxed Ge film on a Si substrate.

  11. Strain field mapping of dislocations in a Ge/Si heterostructure.

    Science.gov (United States)

    Liu, Quanlong; Zhao, Chunwang; Su, Shaojian; Li, Jijun; Xing, Yongming; Cheng, Buwen

    2013-01-01

    Ge/Si heterostructure with fully strain-relaxed Ge film was grown on a Si (001) substrate by using a two-step process by ultra-high vacuum chemical vapor deposition. The dislocations in the Ge/Si heterostructure were experimentally investigated by high-resolution transmission electron microscopy (HRTEM). The dislocations at the Ge/Si interface were identified to be 90° full-edge dislocations, which are the most efficient way for obtaining a fully relaxed Ge film. The only defect found in the Ge epitaxial film was a 60° dislocation. The nanoscale strain field of the dislocations was mapped by geometric phase analysis technique from the HRTEM image. The strain field around the edge component of the 60° dislocation core was compared with those of the Peierls-Nabarro and Foreman dislocation models. Comparison results show that the Foreman model with a = 1.5 can describe appropriately the strain field around the edge component of a 60° dislocation core in a relaxed Ge film on a Si substrate.

  12. Study on ancient Chinese imitated GE ware by INAA and WDXRF

    Science.gov (United States)

    Xie, Guoxi; Feng, Songlin; Feng, Xiangqian; Wang, Yanqing; Zhu, Jihao; Yan, Lingtong; Li, Yongqiang; Han, Hongye

    2007-11-01

    Imitated GE ware was one of the most famous products of Jingdezhen porcelain field in Ming dynasty (AD 1368-1644). The exterior features of its body and glaze are very marvelous. Black foot, purple mouth and crazing glaze are the main features of imitated GE ware. Until now, the key conditions of resulting these features are not clearly identified. In order to find the critical elements for firing these features, instrumental neutron activation analysis (INAA) and wavelength-dispersive X-ray fluorescence (WDXRF) were used to determine the element abundance patterns of imitated GE ware body and glaze. The experimental data was compared with that of imitated Longquan celadon and of Longquan celadon. The analytical results indicated that Fe, Ti and Na were the critical elements. The body of imitated GE ware which contains high Fe and Ti are the basic conditions of firing its black body, black foot and purple mouth. The glaze of imitated GE ware which contains high Na is the main condition of producing its crazing glaze. Na is the critical element which enlarges the difference in expansion coefficients between the glaze and body of imitated GE ware. Furthermore, Zijin soil was added into kaolin to make the body rich in Fe and Ti. And something which was rich in Na was used to produce crazing glaze in the manufacturing process of imitated GE ware.

  13. Study on ancient Chinese imitated GE ware by INAA and WDXRF

    Energy Technology Data Exchange (ETDEWEB)

    Xie Guoxi [Institute of High Energy Physics, Chinese Academy of Sciences, 19 Yu Quan Lu, Beijing 100049 (China); Graduated University of Chinese Academy of Sciences, Beijing 100049 (China); Feng Songlin [Institute of High Energy Physics, Chinese Academy of Sciences, 19 Yu Quan Lu, Beijing 100049 (China)], E-mail: fengsl@ihep.ac.cn; Feng Xiangqian; Wang Yanqing; Zhu Jihao; Yan Lingtong [Institute of High Energy Physics, Chinese Academy of Sciences, 19 Yu Quan Lu, Beijing 100049 (China); Li Yongqiang; Han Hongye [Beijing Institute of Cultural Relics, Beijing 100009 (China)

    2007-11-15

    Imitated GE ware was one of the most famous products of Jingdezhen porcelain field in Ming dynasty (AD 1368-1644). The exterior features of its body and glaze are very marvelous. Black foot, purple mouth and crazing glaze are the main features of imitated GE ware. Until now, the key conditions of resulting these features are not clearly identified. In order to find the critical elements for firing these features, instrumental neutron activation analysis (INAA) and wavelength-dispersive X-ray fluorescence (WDXRF) were used to determine the element abundance patterns of imitated GE ware body and glaze. The experimental data was compared with that of imitated Longquan celadon and of Longquan celadon. The analytical results indicated that Fe, Ti and Na were the critical elements. The body of imitated GE ware which contains high Fe and Ti are the basic conditions of firing its black body, black foot and purple mouth. The glaze of imitated GE ware which contains high Na is the main condition of producing its crazing glaze. Na is the critical element which enlarges the difference in expansion coefficients between the glaze and body of imitated GE ware. Furthermore, Zijin soil was added into kaolin to make the body rich in Fe and Ti. And something which was rich in Na was used to produce crazing glaze in the manufacturing process of imitated GE ware.

  14. Structure and optical properties of Ge/Si quantum dots formed by driving the evolution of Ge thin films via thermal annealing

    Science.gov (United States)

    Shu, Qijiang; Yang, Jie; Chi, Qingbin; Sun, Tao; Wang, Chong; Yang, Yu

    2018-04-01

    Ge/Si quantum dots (QDs) are fabricated by driving the transformation of a Ge thin film-deposited using the direct current (DC) magnetron sputtering technique by controlling the subsequent in situ annealing processes. The experimental results indicate that, with the increase in annealing temperature, the volume of Ge QDs increases monotonically, while the QD density initially increases then decreases. The maximal QD density can reach 1.1 × 1011 cm‑2 after a 10 min annealing at 650 °C. The Ge–Ge peak of Ge QDs obtained by Raman spectroscopy initially undergoes a blue shift and then a red shift with increasing annealing temperature. This behavior results from the competition between the dislocation and the strain relaxation in QDs. Concurrently, a series of photoelectric detectors are fabricated to evaluate the photoelectric performance of these annealed Ge QD samples. A high-photoelectricity response is demonstrated in the QD sample annealed at 650 °C. Our results pave a promising way for whole-silicon-material optical-electronic integration based on a simple and practicable fabrication method.

  15. GeV electron microtron

    International Nuclear Information System (INIS)

    Anon.

    1980-01-01

    A strong consensus has developed recently in the nuclear physics community that research with electromagnetic probes in the 1 to 2 GeV range generated by a high current 100% duty factor electron accelerator represents an exciting new frontier. Because of this rapidly growing interest, a design group of 5 ANL physicists and accelerator specialists recently reviewed developments in accelerator technology and developed conceptual designs for technical evaluation and subsequent cost analysis. Exploratory designs were developed for two concepts, the linac-stretcher ring and a modified microtron system. These were used to make a critical comparison of the two conceptual designs along with an improved microtron design, the double-sided microtron. The results are presented in Table VIII-I. The double-sided microtron shows promise for development into a substantially less expensive facility than a linac-ring system, but its technical feasibility remains to be established. The potential savings in capital cost are large for the microtron system, perhaps $10 million. They dictate that in the absence of a major technical limitation the double-sided microtron is the preferred design

  16. Experimental determination of the Ta–Ge phase diagram

    Energy Technology Data Exchange (ETDEWEB)

    Araújo Pinto da Silva, Antonio Augusto, E-mail: aaaps@ppgem.eel.usp.br [EEL/USP – Escola de Engenharia de Lorena (EEL), Universidade de São Paulo (USP), Pólo Urbo-Industrial Gleba AI-6, 12602-810 Lorena, SP (Brazil); Coelho, Gilberto Carvalho [EEL/USP – Escola de Engenharia de Lorena (EEL), Universidade de São Paulo (USP), Pólo Urbo-Industrial Gleba AI-6, 12602-810 Lorena, SP (Brazil); UniFoa – Centro Universitário de Volta Redonda, Núcleo de Pesquisa, Campus Três Poços, Avenida Paulo Erlei Alves Abrantes, 1325, Bairro Três Poços, 27240-560 Volta Redonda, RJ (Brazil); Nunes, Carlos Angelo; Suzuki, Paulo Atsushi [EEL/USP – Escola de Engenharia de Lorena (EEL), Universidade de São Paulo (USP), Pólo Urbo-Industrial Gleba AI-6, 12602-810 Lorena, SP (Brazil); Fiorani, Jean Marc; David, Nicolas; Vilasi, Michel [Université de Lorraine, Institut Jean Lamour, Faculté des Sciences et Technologies, BP 70239, F-54506 Vandoeuvre-lès-Nancy (France)

    2013-11-05

    Highlights: •Ta–Ge phase diagram propose for the first time. •The phase αTa{sub 5}Ge{sub 3} was not observed in samples investigated in this work. •Three eutectics reactions where determined with the liquid compositions at 20.5; 28.0; 97.0 at.% Ge. -- Abstract: In the present work, the Ta–Ge phase diagram has been experimentally studied, considering the inexistence of a Ta–Ge phase diagram in the literature. The samples were prepared via arc melting and characterized by Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS) and X-ray Diffraction (XRD). The intermetallics phases βTa{sub 3}Ge, αTa{sub 3}Ge, βTa{sub 5}Ge{sub 3} and TaGe{sub 2} where confirmed in this system. Three eutectics reactions where determined with the liquid compositions at 20.5; 28.0; 97.0 at.% Ge. The phases βTa{sub 3}Ge and βTa{sub 5}Ge{sub 3} solidifies congruently while TaGe{sub 2} is formed through a peritectic transformation. The temperature of the Ta-rich eutectic (L ↔ Ta{sub ss} + βTa{sub 3}Ge) was measured by the Pirani-Alterthum method at 2440 °C and the Ge-rich eutectic (L ↔ TaGe{sub 2} + Ge{sub ss}) by DTA at 937 °C.

  17. Study of the quasi-two body processes including {sigma}(1385) production in {pi}{sup -}p and K{sup -} reactions at 4 GeV/c; Estudio de procesos cuasi-dos cuerpos con produccion de {sigma} (1385) en interacciones {pi}{sup -}p y K{sup p} A 4 GeV/c

    Energy Technology Data Exchange (ETDEWEB)

    Aguilar-Benitez, M; Salicio, J

    1981-07-01

    An analysis of (1385) production in reactions of the type 0{sup +} 1/z 4 +{yields}>-1{sup +} 3+/2 and 0{sup -} + 1/2+{yields} 0{sup -} + 3*/2 is presented. A determination of the {sigma}(1385) production parameters Is performed and the results are compared with the predictions from several models. A transversity amplitudes reconstruction describing the processes {pi} {sup p} ->K(890) {sigma}(1385) and K{sup -}p {yields} 3{yields}{phi}(1385), {zeta}{sup -}{sigma}(1385) is obtained in a model independent way. We observe dominance of unnatural partly exchange in the production mechanisms. Exchanges of exotic quantum numbers are established by the study of {pi}p {yields} K{sup 0}+ {sigma}(1385)s and K{sup -} p{yields}>{pi}+{sigma}(1385){+-} processes. Additive quark model predictions are reasonable agreement with the experimental data. (Author)

  18. Top Mass Measurement at CLIC at 500 GeV

    CERN Document Server

    Simon, Frank; Poss, Stephane

    2012-01-01

    We present a study of the capability of a 500 GeV e+e- collider based on CLIC technology for precision measurements of top quark properties. The analysis is based on full detector simulations of the CLIC_ILD detector concept using Geant4, including realistic background contributions from two photon processes. Event reconstruction is performed using a particle flow algorithm with stringent cuts to control the influence of background. The mass and width of the top quark are studied in fully-hadronic and semi-leptonic decays of ttbar pairs using event samples of signal and standard model background processes corresponding to an integrated luminosity of 100/fb. Statistical uncertainties of the top mass given by the invariant mass of its decay products of 0.08 GeV and 0.09 GeV are obtained for the fully-hadronic and the semi-leptonic decay channel, respectively, demonstrating that similar precision to that at ILC can be achieved at CLIC despite less favorable experimental conditions.

  19. Pair production of pions with symmetric momenta in the range 0.5 <= Psub(T) <= 2.0 GeV/c in 70-GeV p-p collisions

    International Nuclear Information System (INIS)

    Abramov, V.V.; Baldin, V.Yu.; Buzulutskov, A.F.

    1981-01-01

    The process of pion pair production is studied in the 70 GeV pp collisions. The invariant cross section slope of the pp → π + π - + X process as a function of transverse mompsub(T)entum is found to have a break near 1 GeV/c. Fitting the cross section by a sum of two exponents gives the values of powers (12.3+-0.9) (GeV/c) -1 and (8.7+-0.6) (GeV/c) -1 . The experimental points at psub(T)>=1 GeV/c are significantly higher than predictions based on hard scattering models such as quantum chromodynamics and constituent interchange model. The largest disagreement is discovered for calculations of the cross section in the framework of quantum chromodynamics [ru

  20. Transitions of microstructure and photoluminescence properties of the Ge/ZnO multilayer films in certain annealing temperature region

    International Nuclear Information System (INIS)

    Zheng Tianhang; Li Ziquan; Chen Jiankang; Shen Kai; Sun Kefei

    2006-01-01

    The Ge/ZnO multilayer films have been prepared by rf magnetron sputtering. The effects of annealing on the microstructure and photoluminescence properties of the multilayers have been investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier-transform infrared (FTIR) spectrometry and photoluminescence (PL) spectrometry. The investigation of structural properties indicates that Zn 2 GeO 4 has been formed with (220) texture and Zn deficiency from Ge/ZnO multilayer films in the process of annealing. However, lower Zn/Ge ratio can be improved by annealing. The annealed multilayers show three main emission bands at 532, 700, and 761nm, which originate from the transition between oxygen vacancy (V o * ) and Zn vacancies (V Zn ), the radiative recombination of quantum-confined excitons (QCE) in Ge nanocrystals, and the optical transition in the GeO color centers, respectively. Finally, the fabrication of thin film Zn 2 GeO 4 from Ge/ZnO multilayer films by annealing at low temperature provides another approach to prepare the green-emitting oxide phosphor film:Zn 2 GeO 4 :Mn

  1. Different growth mechanisms of Ge by Stranski-Krastanow on Si (111) and (001) surfaces: An STM study

    Energy Technology Data Exchange (ETDEWEB)

    Teys, S.A., E-mail: teys@isp.nsc.ru

    2017-01-15

    Highlights: • Different atomic mechanisms of transition from two-dimensional to three-dimensional-layer growth on Sransky-Krastanov observed. • The transition from 2D–3D Ge growth on Si (111) and (001) is very different. • Various changes in morphology, surface structures and sequence Ge redistribution during the growth shown. • The sequence of appearance of different incorporation places of Ge atoms was shown. - Abstract: Structural and morphological features of the wetting layer formation and the transition to the three-dimensional Ge growth on (111) and (100) Si surfaces under quasi-equilibrium growth conditions were studied by means of scanning tunneling microscopy. The mechanism of the transition from the wetting layer to the three-dimensional Ge growth on Si was demonstrated. The principal differences and general trends of the atomic processes involved in the wetting layers formation on substrates with different orientations were demonstrated. The Ge growth is accompanied by the Ge atom redistribution and partial strain relaxation due to the formation of new surfaces, vacancies and surface structures of a decreased density. The analysis of three-dimensional Ge islands sites nucleation of after the wetting layer formation was carried out on the (111) surface. The transition to the three-dimensional growth at the Si(100) surface begins with single {105} facets nucleation on the rough Ge(100) surface.

  2. Different growth mechanisms of Ge by Stranski-Krastanow on Si (111) and (001) surfaces: An STM study

    International Nuclear Information System (INIS)

    Teys, S.A.

    2017-01-01

    Highlights: • Different atomic mechanisms of transition from two-dimensional to three-dimensional-layer growth on Sransky-Krastanov observed. • The transition from 2D–3D Ge growth on Si (111) and (001) is very different. • Various changes in morphology, surface structures and sequence Ge redistribution during the growth shown. • The sequence of appearance of different incorporation places of Ge atoms was shown. - Abstract: Structural and morphological features of the wetting layer formation and the transition to the three-dimensional Ge growth on (111) and (100) Si surfaces under quasi-equilibrium growth conditions were studied by means of scanning tunneling microscopy. The mechanism of the transition from the wetting layer to the three-dimensional Ge growth on Si was demonstrated. The principal differences and general trends of the atomic processes involved in the wetting layers formation on substrates with different orientations were demonstrated. The Ge growth is accompanied by the Ge atom redistribution and partial strain relaxation due to the formation of new surfaces, vacancies and surface structures of a decreased density. The analysis of three-dimensional Ge islands sites nucleation of after the wetting layer formation was carried out on the (111) surface. The transition to the three-dimensional growth at the Si(100) surface begins with single {105} facets nucleation on the rough Ge(100) surface.

  3. Isothermal cross-sections of Sr-Al-Ge and Ba-Al-Ge systems at 673 K

    International Nuclear Information System (INIS)

    Kutsenok, N.L.; Yanson, T.I.

    1987-01-01

    X-ray and microstructural analyses are used to study phase equilibria in Sr-Al-Ge and Ba-Al-Ge systems. Existence of SrAl 2 Ge 2 , Sr(Al, Ge) 2 Ba(Al, Ge) 2 , Sr 3 Al 2 Ge 2 , Ba 3 Al 2 Ge 2 ternary compounds is confirmed, a new BaGe 4 binary compound and also new ternary compounds of approximate composition Sr 57 Al 30 Ge 13 and Ba 20 Al 40 Ge 40 , which crystal structure is unknown, are detected. Aluminium solubility in SrAl 4 and BaAl 4 binary compounds (0.05 atomic fraction) is determined. Ba(Al, Ge) 2 compound homogeneity region is defined more exactly (aluminium content varies from 0.27 to 0.51 at. fractions)

  4. Effect of Ge atoms on crystal structure and optoelectronic properties of hydrogenated Si-Ge films

    Science.gov (United States)

    Li, Tianwei; Zhang, Jianjun; Ma, Ying; Yu, Yunwu; Zhao, Ying

    2017-07-01

    Optoelectronic and structural properties of hydrogenated microcrystalline silicon-germanium (μc-Si1-xGex:H) alloys prepared by radio-frequency plasma-enhanced chemical vapor deposition (RF-PECVD) were investigated. When the Ge atoms were predominantly incorporated in amorphous matrix, the dark and photo-conductivity decreased due to the reduced crystalline volume fraction of the Si atoms (XSi-Si) and the increased Ge dangling bond density. The photosensitivity decreased monotonously with Ge incorporation under higher hydrogen dilution condition, which was attributed to the increase in both crystallization of Ge and the defect density.

  5. Inspecting the microstructure of electrically active defects at the Ge/GeOx interface

    Science.gov (United States)

    Fanciulli, Marco; Baldovino, Silvia; Molle, Alessandro

    2012-02-01

    High mobility substrates are important key elements in the development of advanced devices targeting a vast range of functionalities. Among them, Ge showed promising properties promoting it as valid candidate to replace Si in CMOS technology. However, the electrical quality of the Ge/oxide interface is still a problematic issue, in particular for the observed inversion of the n-type Ge surface, attributed to the presence of dangling bonds inducing a severe band bending [1]. In this scenario, the identification of electrically active defects present at the Ge/oxide interface and the capability to passivate or anneal them becomes a mandatory issue aiming at an electrically optimized interface. We report on the application of highly sensitive electrically detected magnetic resonance (EDMR) techniques in the investigation of defects at the interface between Ge and GeO2 (or GeOx), including Ge dangling bonds and defects in the oxide [2]. In particular we will investigate how different surface orientations, e.g. the (001) against the (111) Ge surface, impacts the microstructure of the interface defects. [1] P. Tsipas and A. Dimoulas, Appl. Phys. Lett. 94, 012114 (2009) [2] S. Baldovino, A. Molle, and M. Fanciulli, Appl. Phys. Lett. 96, 222110 (2010)

  6. Electron Transport Properties of Ge nanowires

    Science.gov (United States)

    Hanrath, Tobias; Khondaker, Saiful I.; Yao, Zhen; Korgel, Brian A.

    2003-03-01

    Electron Transport Properties of Ge nanowires Tobias Hanrath*, Saiful I. Khondaker, Zhen Yao, Brian A. Korgel* *Dept. of Chemical Engineering, Dept. of Physics, Texas Materials Institute, and Center for Nano- and Molecular Science and Technology University of Texas at Austin, Austin, Texas 78712-1062 e-mail: korgel@mail.che.utexas.edu Germanium (Ge) nanowires with diameters ranging from 6 to 50 nm and several micrometer in length were grown via a supercritical fluid-liquid-solid synthesis. Parallel electron energy loss spectroscopy (PEELS) was employed to study the band structure and electron density in the Ge nanowires. The observed increase in plasmon peak energy and peak width with decreasing nanowire diameter is attributed to quantum confinement effects. For electrical characterization, Ge nanowires were deposited onto a patterned Si/SiO2 substrate. E-beam lithography was then used to form electrode contacts to individual nanowires. The influence of nanowire diameter, surface chemistry and crystallographic defects on electron transport properties were investigated and the comparison of Ge nanowire conductivity with respect to bulk, intrinsic Ge will be presented.

  7. Synthesis and characterization of Ge–Cr-based intermetallic compounds: GeCr3, GeCCr3, and GeNCr3

    International Nuclear Information System (INIS)

    Lin, S.; Tong, P.; Wang, B.S.; Huang, Y.N.; Song, W.H.; Sun, Y.P.

    2014-01-01

    Highlights: • Polycrystalline samples of GeCr 3 , GeCCr 3 , and GeNCr 3 are synthesized by using solid state reaction method. • A good quality of our samples is verified by the Rietveld refinement and electrical transport measurement. • We present a comprehensive understanding of physical properties of GeCr 3 , GeCCr 3 , and GeNCr 3 . -- Abstract: We report the synthesis of GeCr 3 , GeCCr 3 , and GeNCr 3 polycrystalline compounds, and present a systematic study of this series by the measurements of X-ray diffraction (XRD), magnetism, electrical/thermal transport, specific heat, and Hall coefficient. Good quality of our samples is verified by quite small value of residual resistivity and considerably large residual resistivity ratio. Based on the Rietveld refinement of XRD data, the crystallographic parameters are obtained, and, correspondingly, the sketches of crystal structure are plotted for all the samples. The ground states of GeCr 3 , GeCCr 3 , and GeNCr 3 are paramagnetic/antiferromagnetic metal, and even a Fermi-liquid behavior is observed in electrical transport at low temperatures. Furthermore, the analysis of the thermal conductivity data suggests the electron thermal conductivity plays a major role in total thermal conductivity for GeCr 3 at low temperatures, while the phonon thermal conductivity is dominant for GeCCr 3 and GeNCr 3 at high temperatures. The negative value of Seebeck coefficient and Hall coefficient indicate that the charge carriers are electron-type for GeCr 3 , GeCCr 3 , and GeNCr 3

  8. Black GE based on crystalline/amorphous core/shell nanoneedle arrays

    Science.gov (United States)

    Javey, Ali; Chueh, Yu-Lun; Fan, Zhiyong

    2014-03-04

    Direct growth of black Ge on low-temperature substrates, including plastics and rubber is reported. The material is based on highly dense, crystalline/amorphous core/shell Ge nanoneedle arrays with ultrasharp tips (.about.4 nm) enabled by the Ni catalyzed vapor-solid-solid growth process. Ge nanoneedle arrays exhibit remarkable optical properties. Specifically, minimal optical reflectance (<1%) is observed, even for high angles of incidence (.about.75.degree.) and for relatively short nanoneedle lengths (.about.1 .mu.m). Furthermore, the material exhibits high optical absorption efficiency with an effective band gap of .about.1 eV. The reported black Ge can have important practical implications for efficient photovoltaic and photodetector applications on nonconventional substrates.

  9. Fragment formation in GeV-energy proton and light heavy-ion induced reactions

    International Nuclear Information System (INIS)

    Murakami, T.; Haga, M.; Haseno, M.

    2002-01-01

    We have investigated similarities and differences among the fragment formation processes in GeV-energy light-ion and light heavy-ion induced reactions. We have newly measured inclusive and exclusive energy spectra of intermediate mass fragments (3 ≤ Z ≤ 30; IMFs) for 8-GeV 16 O and 20 Ne and 12-GeV 20 Ne induced target multifragmentations (TMFs) in order to compare them with those previously measured for 8- and 12-GeV proton induced TMFs. We fond noticeable difference in their spectrum shapes and magnitudes but all of them clearly indicate the existence of sideward-peaked components, indicating fragment formations are mainly dictated not by a incident energy per nucleon but by a total energy of the projectile. (author)

  10. Enhanced Emission of Quantum System in Si-Ge Nanolayer Structure.

    Science.gov (United States)

    Huang, Zhong-Mei; Huang, Wei-Qi; Dong, Tai-Ge; Wang, Gang; Wu, Xue-Ke

    2016-12-01

    It is very interesting that the enhanced peaks near 1150 and 1550 nm are observed in the photoluminescence (PL) spectra in the quantum system of Si-Ge nanolayer structure, which have the emission characteristics of a three-level system with quantum dots (QDs) pumping and emission of quasi-direct-gap band, in our experiment. In the preparing process of Si-Ge nanolayer structure by using a pulsed laser deposition method, it is discovered that the nanocrystals of Si and Ge grow in the (100) and (111) directions after annealing or electron beam irradiation. The enhanced PL peaks with multi-longitudinal-mode are measured at room temperature in the super-lattice of Si-Ge nanolayer quantum system on SOI.

  11. Memory properties of a Ge nanoring MOS device fabricated by pulsed laser deposition.

    Science.gov (United States)

    Ma, Xiying

    2008-07-09

    The non-volatile charge-storage properties of memory devices with MOS structure based on Ge nanorings have been studied. The two-dimensional Ge nanorings were prepared on a p-Si(100) matrix by means of pulsed laser deposition (PLD) using the droplet technique combined with rapid annealing. Complete planar nanorings with well-defined sharp inner and outer edges were formed via an elastic self-transformation droplet process, which is probably driven by the lateral strain of the Ge/Si layers and the surface tension in the presence of Ar gas. The low leakage current was attributed to the small roughness and the few interface states in the planar Ge nanorings, and also to the effect of Coulomb blockade preventing injection. A significant threshold-voltage shift of 2.5 V was observed when an operating voltage of 8 V was implemented on the device.

  12. Pair phase transition and its evolution on even 64-68Ge isotopes

    International Nuclear Information System (INIS)

    Tong Hong; Shi Zhuyi

    2004-01-01

    By using a microscopic sdIBM-2+2q . p . approach which is the phenomenological core plus two-quasi-particle model and the experimental single-particle energies, the levels of the ground-band, β-band, γ-band, and partial two-quasi-particle states on 64-68 Ge isotopes are successfully reproduced. Based on the phenomenological model and microscopic approach, it has been deduced that no s-boson in the nucleus is breaking up and aligning; and that when one d-boson does, the minimum aligned energy can be calculated. This paper explicitly indicates that, with the increase of neutron number, an evolution process of PPT objects, i.e. from the two-quasi-proton states (on 64 Ge nucleus) to the two-quasi-neutron states (on 68 Ge nucleus) may take place in even Ge isotopes. (authors)

  13. Molecular beam epitaxy grown Ge/Si pin layer sequence for photonic devices

    International Nuclear Information System (INIS)

    Schulze, J.; Oehme, M.; Werner, J.

    2012-01-01

    A key challenge to obtain a convergence of classical Si-based microelectronics and optoelectronics is the manufacturing of photonic integrated circuits integrable into classical Si-based integrated circuits. This integration would be greatly enhanced if similar facilities and technologies could be used. Therefore one approach is the development of optoelectronic components and devices made from group-IV-based materials such as SiGe, Ge or Ge:Sn. In this paper the optoelectronic performances of a pin diode made from a Ge/Si heterostructure pin layer sequence grown by molecular beam epitaxy are discussed. After a detailed description of the layer sequence growth and the device manufacturing process it will be shown that – depending on the chosen operating point and device design – the diode serves as a broadband high speed photo detector, Franz–Keldysh effect modulator or light emitting diode.

  14. Molecular beam epitaxy grown Ge/Si pin layer sequence for photonic devices

    Energy Technology Data Exchange (ETDEWEB)

    Schulze, J., E-mail: schulze@iht.uni-stuttgart.de; Oehme, M.; Werner, J.

    2012-02-01

    A key challenge to obtain a convergence of classical Si-based microelectronics and optoelectronics is the manufacturing of photonic integrated circuits integrable into classical Si-based integrated circuits. This integration would be greatly enhanced if similar facilities and technologies could be used. Therefore one approach is the development of optoelectronic components and devices made from group-IV-based materials such as SiGe, Ge or Ge:Sn. In this paper the optoelectronic performances of a pin diode made from a Ge/Si heterostructure pin layer sequence grown by molecular beam epitaxy are discussed. After a detailed description of the layer sequence growth and the device manufacturing process it will be shown that - depending on the chosen operating point and device design - the diode serves as a broadband high speed photo detector, Franz-Keldysh effect modulator or light emitting diode.

  15. Atomic-scale Ge diffusion in strained Si revealed by quantitative scanning transmission electron microscopy

    Science.gov (United States)

    Radtke, G.; Favre, L.; Couillard, M.; Amiard, G.; Berbezier, I.; Botton, G. A.

    2013-05-01

    Aberration-corrected scanning transmission electron microscopy is employed to investigate the local chemistry in the vicinity of a Si0.8Ge0.2/Si interface grown by molecular-beam epitaxy. Atomic-resolution high-angle annular dark field contrast reveals the presence of a nonuniform diffusion of Ge from the substrate into the strained Si thin film. On the basis of multislice calculations, a model is proposed to quantify the experimental contrast, showing that the Ge concentration in the thin film reaches about 4% at the interface and decreases monotonically on a typical length scale of 10 nm. Diffusion occurring during the growth process itself therefore appears as a major factor limiting the abruptness of interfaces in the Si-Ge system.

  16. Synthesis of GeSe2 Nanobelts Using Thermal Evaporation and Their Photoelectrical Properties

    Directory of Open Access Journals (Sweden)

    Lijie Zhang

    2014-01-01

    Full Text Available GeSe2 nanobelts were synthesized via a simple thermal-evaporation process by using gold particles as catalyst and GeSe2 flakes as starting materials. The morphology, crystal structure, and composition were characterized with scanning electron microscopy (SEM, high-resolution transmission electron microscopy (TEM, X-ray diffraction spectroscopy (XRD, X-ray photoelectron spectroscopy (XPS, and energy-dispersive X-ray spectroscopy (EDS. SEM micrographs show that most of GeSe2 nanobelts have distinct segmented structures (wide belt, zigzag belt, and narrow belt. A possible mechanism was proposed for the growth of segmented nanobelts. It is possible that the growth of the segmented nanobelts is dominated by both vapor-liquid-solid and vapor-solid mechanisms. Devices made of single GeSe2 nanobelt have been fabricated and their photoelectrical property has been investigated. Results indicate that these nanobelt devices are potential building blocks for optoelectronic applications.

  17. Stress-directed compositional patterning of SiGe substrates for lateral quantum barrier manipulation

    International Nuclear Information System (INIS)

    Ghosh, Swapnadip; Kaiser, Daniel; Sinno, Talid; Bonilla, Jose; Han, Sang M.

    2015-01-01

    While vertical stacking of quantum well and dot structures is well established in heteroepitaxial semiconductor materials, manipulation of quantum barriers in the lateral directions poses a significant engineering challenge. Here, we demonstrate lateral quantum barrier manipulation in a crystalline SiGe alloy using structured mechanical fields to drive compositional redistribution. To apply stress, we make use of a nano-indenter array that is pressed against a Si 0.8 Ge 0.2 wafer in a custom-made mechanical press. The entire assembly is then annealed at high temperatures, during which the larger Ge atoms are selectively driven away from areas of compressive stress. Compositional analysis of the SiGe substrates reveals that this approach leads to a transfer of the indenter array pattern to the near-surface elemental composition, resulting in near 100% Si regions underneath each indenter that are separated from each other by the surrounding Si 0.8 Ge 0.2 bulk. The “stress transfer” process is studied in detail using multiscale computer simulations that demonstrate its robustness across a wide range of applied stresses and annealing temperatures. While the “Si nanodot” structures formed here are not intrinsically useful as quantum structures, it is anticipated that the stress transfer process may be modified by judicious control of the SiGe film thickness and indenter array pattern to form more technologically useful structures

  18. One-step Ge/Si epitaxial growth.

    Science.gov (United States)

    Wu, Hung-Chi; Lin, Bi-Hsuan; Chen, Huang-Chin; Chen, Po-Chin; Sheu, Hwo-Shuenn; Lin, I-Nan; Chiu, Hsin-Tien; Lee, Chi-Young

    2011-07-01

    Fabricating a low-cost virtual germanium (Ge) template by epitaxial growth of Ge films on silicon wafer with a Ge(x)Si(1-x) (0 deposition method in one step by decomposing a hazardousless GeO(2) powder under hydrogen atmosphere without ultra-high vacuum condition and then depositing in a low-temperature region. X-ray diffraction analysis shows that the Ge film with an epitaxial relationship is along the in-plane direction of Si. The successful growth of epitaxial Ge films on Si substrate demonstrates the feasibility of integrating various functional devices on the Ge/Si substrates.

  19. Pseudomorphic GeSiSn, SiSn and Ge layers in strained heterostructures

    Science.gov (United States)

    Timofeev, V. A.; Nikiforov, A. I.; Tuktamyshev, A. R.; Mashanov, V. I.; Loshkarev, I. D.; Bloshkin, A. A.; Gutakovskii, A. K.

    2018-04-01

    The GeSiSn, SiSn layer growth mechanisms on Si(100) were investigated and the kinetic diagrams of the morphological GeSiSn, SiSn film states in the temperature range of 150 °C-450 °C at the tin content from 0% to 35% were built. The phase diagram of the superstructural change on the surface of Sn grown on Si(100) in the annealing temperature range of 0 °C-850 °C was established. The specular beam oscillations were first obtained during the SiSn film growth from 150 °C to 300 °C at the Sn content up to 35%. The transmission electron microscopy and x-ray diffractometry data confirm the crystal perfection and the pseudomorphic GeSiSn, SiSn film state, and also the presence of smooth heterointerfaces between GeSiSn or SiSn and Si. The photoluminescence for the multilayer periodic GeSiSn/Si structures in the range of 0.6-0.8 eV was detected. The blue shift with the excitation power increase is observed suggesting the presence of a type II heterostructure. The creation of tensile strained Ge films, which are pseudomorphic to the underlying GeSn layer, is confirmed by the results of the formation and analysis of the reciprocal space map in the x-ray diffractometry. The tensile strain in the Ge films reached the value in the range of 0.86%-1.5%. The GeSn buffer layer growth in the Sn content range from 8% to 12% was studied. The band structure of heterosystems based on pseudomorphic GeSiSn, SiSn and Ge layers was calculated and the valence and conduction band subband position dependences on the Sn content were built. Based on the calculation, the Sn content range in the GeSiSn, SiSn, and GeSn layers, which corresponds to the direct bandgap GeSiSn, SiSn, and Ge material, was obtained.

  20. From X-Rays to MRI: Physics in GE

    Science.gov (United States)

    Schmitt, Roland W.

    2004-03-01

    The GE Research Laboratory, founded in 1900, became the first laboratory of scientific research in U.S. industry. William Coolidge, a physicist, joined the laboratory in 1905 and produced two advances of immense importance. The first, ductile tungsten, is still the heart of every incandescent light bulb. The second, the "Coolidge" X-Ray tube, remains an essential tool of modern medicine. In the process, Coolidge explored two main approaches of physics in industry. One addresses a commercial problem or opportunity (better light bulbs) and finds interesting physics. The other explores interesting physics (X-rays) and creates a commercial opportunity. This paper addresses the mix of these approaches during GE's years as an "electric" (and therefore physics-based) company. Episodes include the following: the work of Irving Langmuir (1932 Nobel laureate in chemistry, but as much physicist as chemist); the post-World War II "golden age of industrial physics" when the endless frontier offered opportunities from nuclear power to diamond making to superconductivity; the Nobel-prize winning work of Ivar Giaever; and interdisciplinary efforts that enabled GE to become a world business leader in two medical diagnostic technologies it did not invent: computed tomography and magnetic resonance imaging. I will speculate on whether this mix of problem-driven and opportunity-driven effort is as relevant to the 21st century as it was to the 20th.

  1. Epitaxial Ge-crystal arrays for X-ray detection

    International Nuclear Information System (INIS)

    Kreiliger, T; Falub, C V; Müller, E; Känel, H von; Isa, F; Isella, G; Chrastina, D; Bergamaschini, R; Marzegalli, A; Miglio, L; Kaufmann, R; Niedermann, P; Neels, A; Dommann, A; Meduňa, M

    2014-01-01

    Monolithic integration of an X-ray absorber layer on a Si CMOS chip might be a potentially attractive way to improve detector performance at acceptable costs. In practice this requires, however, the epitaxial growth of highly mismatched layers on a Si-substrate, both in terms of lattice parameters and thermal expansion coefficients. The generation of extended crystal defects, wafer bowing and layer cracking have so far made it impossible to put the simple concept into practice. Here we present a way in which the difficulties of fabricating very thick, defect-free epitaxial layers may be overcome. It consists of an array of densely packed, three-dimensional Ge-crystals on a patterned Si(001) substrate. The finite gap between neighboring micron-sized crystals prevents layer cracking and substrate bowing, while extended defects are driven to the crystal sidewalls. We show that the Ge-crystals are indeed defect-free, despite the lattice misfit of 4.2%. The electrical characteristics of individual Ge/Si heterojunction diodes are obtained from in-situ measurements inside a scanning electron microscope. The fabrication of monolithically integrated detectors is shown to be compatible with Si-CMOS processing

  2. Progress toward a practical Nb--Ge conductor

    International Nuclear Information System (INIS)

    Braginski, A.I.; Gavaler, J.R.; Roland, G.W.; Daniel, M.R.; Janocko, M.A.; Santhanam, A.T.

    1976-01-01

    Properties of high-T/sub c/ Nb--Ge films deposited by sputtering and by chemical vapor deposition (CVD) have been investigated. Results of sputtering in the presence of controlled levels of O 2 , N 2 , Si, and of reactive sputtering in Ar--GeH 4 , suggest that the high-T/sub c/ A15 phase is impurity- or defect-stabilized. In CVD deposits two tetragonal modifications were found: sigma and T2, the latter probably stabilized by Cl 2 . High critical current densities, J/sub c/ (H, T) of fine-grained sputtered films are attributed to flux pinning on A15 grain boundaries. In coarse-grained CVD films high self-field J/sub c/'s, 10 6 to 10 7 A cm -2 at T = 4.2 0 K, are attributed to pinning on dispersed sigma-phase. Comparably high J/sub c/'s were also obtained in CVD A15 films doped with impurities. Low field ac losses p (H, T) were correlated with J/sub c/ and coating geometries. The feasibility of fabricating multifilamentary composite conductors by CVD was demonstrated experimentally and a fabrication process for long Nb 3 Ge CVD tapes is being developed

  3. Thermal transport through Ge-rich Ge/Si superlattices grown on Ge(0 0 1)

    Science.gov (United States)

    Thumfart, L.; Carrete, J.; Vermeersch, B.; Ye, N.; Truglas, T.; Feser, J.; Groiss, H.; Mingo, N.; Rastelli, A.

    2018-01-01

    The cross-plane thermal conductivities of Ge-rich Si/Ge superlattices have been measured using both time-domain thermoreflectance and the differential 3ω method. The superlattices were grown by molecular beam epitaxy on Ge(0 0 1) substrates. Crystal quality and structural information were investigated by x-ray diffractometry and transmission electron microscopy. The influence of segregation during growth on the composition profiles was modeled using the experimental growth temperatures and deposition rates. Those profiles were then employed to obtain parameter-free theoretical estimates of the thermal conductivity by combining first-principles calculations, Boltzmann transport theory and phonon Green’s functions. Good agreement between theory and experiment is observed. The thermal conductivity shows a strong dependence on the composition and the thickness of the samples. Moreover, the importance of the composition profile is reflected in the fact that the thermal conductivity of the superlattices is considerably lower than predicted values for alloys with the same average composition and thickness. Measurement on different samples with the same Si layer thickness and number of periods, but different Ge layer thickness, show that the thermal resistance is only weakly dependent on the Ge layers. We analyze this phenomenon based on the first-principles mode, and build an approximate parametrization showing that, in this regime, the resistivity of a SL is roughly linear on the amount of Si.

  4. Electromigration techniques for Ge(II) and Ge(IV) separation in germanium thio compounds

    Energy Technology Data Exchange (ETDEWEB)

    Facetti, J F; Vallejos, A [Asuncion Naciona Univ. (Paraguay). Inst. de Ciencias

    1971-01-01

    Using H.V. electromigration techniques, a good separation of the Ge(II) and Ge(IV) was achieved. The procedure was carried out in alkaline medium. And the final position of the separated species was established by, either neutron activation of the papa strips or chromatic reactions.

  5. The Role of Ge Wetting Layer and Ge Islands in Si MSM Photodetectors

    International Nuclear Information System (INIS)

    Mahmodi, H.; Hashim, M. R.

    2010-01-01

    In this work, Ge thin films were deposited on silicon substrates by radio frequency magnetron sputtering to form Ge islands from Ge layer on Si substrate during post-growth rapid thermal annealing (RTA). The size of the islands decreases from 0.6 to 0.1 as the rapid thermal annealing time increases from 30 s to 60 s at 900 deg. C. Not only that the annealing produces Ge islands but also wetting layer. Energy Dispersive X-ray Spectroscopy (EDX) and Scanning Electron Microscopy (SEM) were employed for structural analysis of Ge islands. Metal-Semiconductor-Metal photodetectors (MSM PDs) were fabricated on Ge islands (and wetting layer)/Si. The Ge islands and wetting layer between the contacts of the fabricated devices are etched in order to see their effects on the device. The performance of the Ge islands MSM-PD was evaluated by dark and photo current-voltage (I-V) measurements at room temperature (RT). It was found that the device with island and wetting layer significantly enhance the current gain (ratio of photo current to dark current) of the device.

  6. Electromigration techniques for Ge(II) and Ge(IV) separation in germanium thio compounds

    International Nuclear Information System (INIS)

    Facetti, J.F.; Vallejos, A.

    1971-01-01

    Using H.V. electromigration techniques, a good separation of the Ge(II) and Ge(IV) was achieved. The procedure was carried out in alkaline medium. And the final position of the separated species was established by, either neutron activation of the papa strips or chromatic reactions

  7. Precipitation and strengthening phenomena in Al-Si-Ge and Al-Cu-Si-Ge alloys

    International Nuclear Information System (INIS)

    Mitlin, D.; Morris, J.W.; Dahmen, U.; Radmilovic, V.

    2000-01-01

    The objective of this work was to determine whether Al rich Al-Si-Ge and 2000 type Al-Cu-Si-Ge alloys have sufficient hardness to be useful for structural applications. It is shown that in Al-Si-Ge it is not possible to achieve satisfactory hardness through a conventional heat treatment. This result is explained in terms of sluggish precipitation of the diamond-cubic Si-Ge phase coupled with particle coarsening. However, Al-Cu-Si-Ge displayed a uniquely fast aging response, a high peak hardness and a good stability during prolonged aging. The high hardness of the Cu containing alloy is due to the dense and uniform distribution of fine θ' precipitates (metastable Al 2 Cu) which are heterogeneously nucleated on the Si-Ge particles. High resolution TEM demonstrated that in both alloys all the Si-Ge precipitates start out, and remain multiply twinned throughout the aging treatment. Since the twinned section of the precipitate does not maintain a low index interface with the matrix, the Si-Ge precipitates are equiaxed in morphology. Copyright (2000) AD-TECH - International Foundation for the Advancement of Technology Ltd

  8. Phase equilibria, crystal chemistry, electronic structure and physical properties of Ag-Ba-Ge clathrates

    Energy Technology Data Exchange (ETDEWEB)

    Zeiringer, I.; Chen Mingxing [Institute of Physical Chemistry, University of Vienna, Waehringerstr. 42, 1090 Wien (Austria); Bednar, I.; Royanian, E.; Bauer, E. [Institute of Solid State Physics, Vienna University of Technology, Wiedner Hauptstr. 8-10, 1040 Wien (Austria); Podloucky, R.; Grytsiv, A. [Institute of Physical Chemistry, University of Vienna, Waehringerstr. 42, 1090 Wien (Austria); Rogl, P., E-mail: peter.franz.rogl@univie.ac.at [Institute of Physical Chemistry, University of Vienna, Waehringerstr. 42, 1090 Wien (Austria); Effenberger, H. [Institute of Mineralogy and Crystallography, University of Vienna, A-1090 Wien (Austria)

    2011-04-15

    In the Ag-Ba-Ge system the clathrate type-{Iota} solid solution, Ba{sub 8}Ag{sub x}Ge{sub 46-x-y{open_square}y}, extends at 800 deg. C from binary Ba{sub 8}Ge{sub 43{open_square}3} ({open_square} is a vacancy) to Ba{sub 8}Ag{sub 5.3}Ge{sub 40.7}. For the clathrate phase (1 {<=} x {<=} 5.3) the cubic space group Pm3-bar n was established by X-ray powder diffraction and confirmed by X-ray single-crystal analyses of the samples Ba{sub 8}Ag{sub 2.3}Ge{sub 41.9{open_square}1.8} and Ba{sub 8}Ag{sub 4.4}Ge{sub 41.3{open_square}0.3}. Increasing the concentration of Ag causes the lattice parameters of the solid solution to increase linearly from a value of a = 1.0656 (x = 0, y = 3) to a = 1.0842 (x = 4.8, y = 0) nm. Site preference determination using X-ray refinement reveals that Ag atoms preferentially occupy the 6d site randomly mixed with Ge and vacancies, which become filled in the compound Ba{sub 8}Ag{sub 4.8}Ge{sub 41.2} when the Ag content increases. At 600 {sup o}C the phase region of the clathrate solution Ba{sub 8}Ag{sub x}Ge{sub 46-x-y{open_square}y} becomes separated from the Ba-Ge boundary and extends from 6.6 to 9.8 at.% Ag. The compound Ba{sub 6}Ge{sub 25} (clathrate type-{Iota}X) dissolves at 800 {sup o}C a maximum of 1.5 at.% Ag. The homogeneity regions of the two ternary compounds BaAg{sub 2-x}Ge{sub 2+x} (ThCr{sub 2}Si{sub 2}-type, 0.2 {<=} x {<=} 0.7) and Ba(Ag{sub 1-x}Ge{sub x}){sub 2} (AlB{sub 2}-type, 0.65 {<=} x {<=} 0.75) were established at 800 deg. C. Studies of transport properties for the series of Ba{sub 8}Ag{sub x}Ge{sub 46-x-y{open_square}y} compounds evidenced that electrons are the predominant charge carriers with the Fermi energy close to a gap. Its position can be fine-tuned by the substitution of Ge by Ag atoms and by mechanical processing of the starting material, Ba{sub 8}Ge{sub 43}. The proximity of the electronic structure at Fermi energy of Ba{sub 8}Ag{sub x}Ge{sub 46-x-y{open_square}y} to a gap is also corroborated by density

  9. Enhanced formation of Ge nanocrystals in Ge : SiO2 layers by swift heavy ions

    International Nuclear Information System (INIS)

    Antonova, I V; Volodin, V A; Marin, D M; Skuratov, V A; Smagulova, S A; Janse van Vuuren, A; Neethling, J; Jedrzejewski, J; Balberg, I

    2012-01-01

    In this paper we report the ability of swift heavy Xe ions with an energy of 480 MeV and a fluence of 10 12 cm -2 to enhance the formation of Ge nanocrystals within SiO 2 layers with variable Ge contents. These Ge-SiO 2 films were fabricated by the co-sputtering of Ge and quartz sources which followed various annealing procedures. In particular, we found that the irradiation of the Ge : SiO 2 films with subsequent annealing at 500 °C leads to the formation of a high concentration of nanocrystals (NCs) with a size of 2-5 nm, whereas without irradiation only amorphous inclusions were observed. This effect, as evidenced by Raman spectra, is enhanced by pre-irradiation at 550 °C and post-irradiation annealing at 600 °C, which also leads to the observation of room temperature visible photoluminescence. (paper)

  10. The gastroesophageal (GE) scintiscan in detection of GE reflux and pulmonary aspiration in children

    International Nuclear Information System (INIS)

    Arasu, T.S.; Franken, E.A.; Wyllie, R.; Eigen, H.; Grosfeld, J.L.; Siddiqui, A.R.; Fitzgerald, J.F.

    1980-01-01

    Gastroesophageal scintiscans and barium examinations were performed on 30 children with documented GE reflux and 13 control patients. After instillation of 2 mCi of Tc99m sulfur colloid into the stomach, serial images of the abdomen and thorax were obtained. The GE scintiscan was positive in 17 of 30 with GE reflux; the barium study was positive in 15 of 30. A positive scintiscan and/or barium study was found in 21 of 30 patients with reflux, and none of the controls. Pulmonay aspiration of gastric contents was not detected by either method. We conclude that the GE scintiscan is complementary to barium studies in the diagnosis of GE reflux, and neither study approaches the accuracy of more sophisticated tests [fr

  11. 70Ge, 72Ge, 74Ge, 76Ge(d,3He)69Ga, 71Ga, 73Ga, 75Ga reactions at 26 MeV

    International Nuclear Information System (INIS)

    Rotbard, G.; La Rana, G.; Vergnes, M.; Berrier, G.; Kalifa, J.; Guilbaut, G.; Tamisier, R.

    1978-01-01

    The 70 Ge, 72 Ge, 74 Ge, 76 Ge(d, 3 He) 69 Ga, 71 Ga, 73 Ga, 75 Ga reactions have been studied at 26 MeV with 15 keV resolution (F.W.H.M), using the Orsay MP tandem accelerator and a split pole magnetic spectrometer. The spectroscopic factors are determined for 15 levels in 69 Ga and 11 levels in each of the 3 other Ga isotopes. Level schemes are proposed for the practically unknown 73 Ga and 75 Ga. Very simple model wave functions previously proposed for Ge nuclei are seen to reproduce quite well the measured occupation numbers for the proton orbitals. Anomalies in these occupation numbers are observed between Z=31 and 32 and between N=40 and 42, this last one corresponding to the structural transition observed recently in a comparison of the (p,t) and (t,p) reactions. These anomalies could be related to changes in the nuclear shape

  12. Experimental formation of Pb, Sn, Ge and Sb sulfides, selenides and chlorides in the presence of sal ammoniac: A contribution to the understanding of the mineral formation processes in coal wastes self-ignition

    Czech Academy of Sciences Publication Activity Database

    Laufek, F.; Veselovský, F.; Drábek, M.; Kříbek, B.; Klementová, Mariana

    176-177, May (2017), s. 1-7 ISSN 0166-5162 Institutional support: RVO:68378271 Keywords : coal wastes * metalloids * mineral formation * self-burning processes Subject RIV: DB - Geology ; Mineralogy OBOR OECD: Geology Impact factor: 4.783, year: 2016

  13. Voltage Controlled Hot Carrier Injection Enables Ohmic Contacts Using Au Island Metal Films on Ge.

    Science.gov (United States)

    Ganti, Srinivas; King, Peter J; Arac, Erhan; Dawson, Karl; Heikkilä, Mikko J; Quilter, John H; Murdoch, Billy; Cumpson, Peter; O'Neill, Anthony

    2017-08-23

    We introduce a new approach to creating low-resistance metal-semiconductor ohmic contacts, illustrated using high conductivity Au island metal films (IMFs) on Ge, with hot carrier injection initiated at low applied voltage. The same metallization process simultaneously allows ohmic contact to n-Ge and p-Ge, because hot carriers circumvent the Schottky barrier formed at metal/n-Ge interfaces. A 2.5× improvement in contact resistivity is reported over previous techniques to achieve ohmic contact to both n- and p- semiconductor. Ohmic contacts at 4.2 K confirm nonequilibrium current transport. Self-assembled Au IMFs are strongly orientated to Ge by annealing near the Au/Ge eutectic temperature. Au IMF nanostructures form, provided the Au layer is below a critical thickness. We anticipate that optimized IMF contacts may have applicability to many material systems. Optimizing this new paradigm for metal-semiconductor contacts offers the prospect of improved nanoelectronic systems and the study of voltage controlled hot holes and electrons.

  14. GeNemo: a search engine for web-based functional genomic data.

    Science.gov (United States)

    Zhang, Yongqing; Cao, Xiaoyi; Zhong, Sheng

    2016-07-08

    A set of new data types emerged from functional genomic assays, including ChIP-seq, DNase-seq, FAIRE-seq and others. The results are typically stored as genome-wide intensities (WIG/bigWig files) or functional genomic regions (peak/BED files). These data types present new challenges to big data science. Here, we present GeNemo, a web-based search engine for functional genomic data. GeNemo searches user-input data against online functional genomic datasets, including the entire collection of ENCODE and mouse ENCODE datasets. Unlike text-based search engines, GeNemo's searches are based on pattern matching of functional genomic regions. This distinguishes GeNemo from text or DNA sequence searches. The user can input any complete or partial functional genomic dataset, for example, a binding intensity file (bigWig) or a peak file. GeNemo reports any genomic regions, ranging from hundred bases to hundred thousand bases, from any of the online ENCODE datasets that share similar functional (binding, modification, accessibility) patterns. This is enabled by a Markov Chain Monte Carlo-based maximization process, executed on up to 24 parallel computing threads. By clicking on a search result, the user can visually compare her/his data with the found datasets and navigate the identified genomic regions. GeNemo is available at www.genemo.org. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

  15. Monolithic Ge-on-Si lasers for large-scale electronic-photonic integration

    Science.gov (United States)

    Liu, Jifeng; Kimerling, Lionel C.; Michel, Jurgen

    2012-09-01

    A silicon-based monolithic laser source has long been envisioned as a key enabling component for large-scale electronic-photonic integration in future generations of high-performance computation and communication systems. In this paper we present a comprehensive review on the development of monolithic Ge-on-Si lasers for this application. Starting with a historical review of light emission from the direct gap transition of Ge dating back to the 1960s, we focus on the rapid progress in band-engineered Ge-on-Si lasers in the past five years after a nearly 30-year gap in this research field. Ge has become an interesting candidate for active devices in Si photonics in the past decade due to its pseudo-direct gap behavior and compatibility with Si complementary metal oxide semiconductor (CMOS) processing. In 2007, we proposed combing tensile strain with n-type doping to compensate the energy difference between the direct and indirect band gap of Ge, thereby achieving net optical gain for CMOS-compatible diode lasers. Here we systematically present theoretical modeling, material growth methods, spontaneous emission, optical gain, and lasing under optical and electrical pumping from band-engineered Ge-on-Si, culminated by recently demonstrated electrically pumped Ge-on-Si lasers with >1 mW output in the communication wavelength window of 1500-1700 nm. The broad gain spectrum enables on-chip wavelength division multiplexing. A unique feature of band-engineered pseudo-direct gap Ge light emitters is that the emission intensity increases with temperature, exactly opposite to conventional direct gap semiconductor light-emitting devices. This extraordinary thermal anti-quenching behavior greatly facilitates monolithic integration on Si microchips where temperatures can reach up to 80 °C during operation. The same band-engineering approach can be extended to other pseudo-direct gap semiconductors, allowing us to achieve efficient light emission at wavelengths previously

  16. Monolithic Ge-on-Si lasers for large-scale electronic–photonic integration

    International Nuclear Information System (INIS)

    Liu, Jifeng; Kimerling, Lionel C; Michel, Jurgen

    2012-01-01

    A silicon-based monolithic laser source has long been envisioned as a key enabling component for large-scale electronic–photonic integration in future generations of high-performance computation and communication systems. In this paper we present a comprehensive review on the development of monolithic Ge-on-Si lasers for this application. Starting with a historical review of light emission from the direct gap transition of Ge dating back to the 1960s, we focus on the rapid progress in band-engineered Ge-on-Si lasers in the past five years after a nearly 30-year gap in this research field. Ge has become an interesting candidate for active devices in Si photonics in the past decade due to its pseudo-direct gap behavior and compatibility with Si complementary metal oxide semiconductor (CMOS) processing. In 2007, we proposed combing tensile strain with n-type doping to compensate the energy difference between the direct and indirect band gap of Ge, thereby achieving net optical gain for CMOS-compatible diode lasers. Here we systematically present theoretical modeling, material growth methods, spontaneous emission, optical gain, and lasing under optical and electrical pumping from band-engineered Ge-on-Si, culminated by recently demonstrated electrically pumped Ge-on-Si lasers with >1 mW output in the communication wavelength window of 1500–1700 nm. The broad gain spectrum enables on-chip wavelength division multiplexing. A unique feature of band-engineered pseudo-direct gap Ge light emitters is that the emission intensity increases with temperature, exactly opposite to conventional direct gap semiconductor light-emitting devices. This extraordinary thermal anti-quenching behavior greatly facilitates monolithic integration on Si microchips where temperatures can reach up to 80 °C during operation. The same band-engineering approach can be extended to other pseudo-direct gap semiconductors, allowing us to achieve efficient light emission at wavelengths previously

  17. Fabrication of Coaxial Si(1-x)Ge(x) Heterostructure Nanowires by O(2) Flow-Induced Bifurcate Reactions.

    Science.gov (United States)

    Kim, Ilsoo; Lee, Ki-Young; Kim, Ungkil; Park, Yong-Hee; Park, Tae-Eon; Choi, Heon-Jin

    2010-06-17

    We report on bifurcate reactions on the surface of well-aligned Si(1-x)Ge(x) nanowires that enable fabrication of two different coaxial heterostructure nanowires. The Si(1-x)Ge(x) nanowires were grown in a chemical vapor transport process using SiCl(4) gas and Ge powder as a source. After the growth of nanowires, SiCl(4) flow was terminated while O(2) gas flow was introduced under vacuum. On the surface of nanowires was deposited Ge by the vapor from the Ge powder or oxidized into SiO(2) by the O(2) gas. The transition from deposition to oxidation occurred abruptly at 2 torr of O(2) pressure without any intermediate region and enables selectively fabricated Ge/Si(1-x)Ge(x) or SiO(2)/Si(1-x)Ge(x) coaxial heterostructure nanowires. The rate of deposition and oxidation was dominated by interfacial reaction and diffusion of oxygen through the oxide layer, respectively.

  18. Magnetic properties of TbTiGe

    International Nuclear Information System (INIS)

    Prokes, K.; Tegus, O.; Brueck, E.; Gortenmulder, T.J.; Boer, F.R. de; Buschow, K.H.J.

    2001-01-01

    We have studied the magnetic properties of the compound TbTiGe by means of neutron diffraction in the temperature range 1.7-310 K. We also report on magnetization measurements made at different temperatures and fields. The compound TbTiGe adopts the tetragonal CeFeSi-structure type and orders antiferromagnetically at T N =286 K. The structure is collinear antiferromagnetic in the whole temperature range below T N , with the magnetic moments aligned along the tetragonal c-axis. The uncommon shape of the temperature dependence of the magnetization observed in our sample is attributed to small amounts of the ferromagnetic low-temperature modification of TbTiGe

  19. The Impact of HCl Precleaning and Sulfur Passivation on the Al2O3/Ge Interface in Ge Metal-Oxide-Semiconductor Capacitors

    International Nuclear Information System (INIS)

    Xue Bai-Qing; Chang Hu-Dong; Sun Bing; Wang Sheng-Kai; Liu Hong-Gang

    2012-01-01

    Surface treatment for Ge substrates using hydrogen chlorine cleaning and chemical passivation are investigated on AuTi/Al 2 O 3 /Ge metal-oxide-semiconductor capacitors. After hydrogen chlorine cleaning, a smooth Ge surface almost free from native oxide is demonstrated by atomic force microscopy and x-ray photoelectron spectroscopy observations. Passivation using a hydrogen chlorine solution is found to form a chlorine-terminated surface, while aqueous ammonium sulfide pretreatment results in a surface terminated by Ge-S bonding. Compared with chlorine-passivated samples, the sulfur-passivated ones show less frequency dispersion and better thermal stability based on capacitance-voltage characterizations. The samples with HCl pre-cleaning and (NH 4 ) 2 S passivation show less frequency dispersion than the HF pre-cleaning and (NH 4 ) 2 S passivated ones. The surface treatment process using hydrogen chlorine cleaning followed by aqueous ammonium sulfide passivation demonstrates a promising way to improve gate dielectric/Ge interface quality. (condensed matter: structure, mechanical and thermal properties)

  20. Search for the Standard Model Higgs boson in $e^+ e^-$ collisions at $\\sqrt{s}$ up to 202 GeV

    CERN Document Server

    Acciarri, M.; Adriani, O.; Aguilar-Benitez, M.; Alcaraz, J.; Alemanni, G.; Allaby, J.; Aloisio, A.; Alviggi, M.G.; Ambrosi, G.; Anderhub, H.; Andreev, Valery P.; Angelescu, T.; Anselmo, F.; Arefev, A.; Azemoon, T.; Aziz, T.; Bagnaia, P.; Bajo, A.; Baksay, L.; Balandras, A.; Baldew, S.V.; Banerjee, S.; Banerjee, Sw.; Barczyk, A.; Barillere, R.; Bartalini, P.; Basile, M.; Batalova, N.; Battiston, R.; Bay, A.; Becattini, F.; Becker, U.; Behner, F.; Bellucci, L.; Berbeco, R.; Berdugo, J.; Berges, P.; Bertucci, B.; Betev, B.L.; Bhattacharya, S.; Biasini, M.; Biland, A.; Blaising, J.J.; Blyth, S.C.; Bobbink, G.J.; Bohm, A.; Boldizsar, L.; Borgia, B.; Bourilkov, D.; Bourquin, M.; Braccini, S.; Branson, J.G.; Brochu, F.; Buffini, A.; Buijs, A.; Burger, J.D.; Burger, W.J.; Cai, X.D.; Capell, M.; Cara Romeo, G.; Carlino, G.; Cartacci, A.M.; Casaus, J.; Castellini, G.; Cavallari, F.; Cavallo, N.; Cecchi, C.; Cerrada, M.; Cesaroni, F.; Chamizo, M.; Chang, Y.H.; Chaturvedi, U.K.; Chemarin, M.; Chen, A.; Chen, G.; Chen, G.M.; Chen, H.F.; Chen, H.S.; Chiefari, G.; Cifarelli, L.; Cindolo, F.; Civinini, C.; Clare, I.; Clare, R.; Coignet, G.; Colino, N.; Costantini, S.; Cotorobai, F.; de la Cruz, B.; Csilling, A.; Cucciarelli, S.; Dai, T.S.; van Dalen, J.A.; D'Alessandro, R.; de Asmundis, R.; Deglon, P.; Degre, A.; Deiters, K.; della Volpe, D.; Delmeire, E.; Denes, P.; DeNotaristefani, F.; De Salvo, A.; Diemoz, M.; Dierckxsens, M.; van Dierendonck, D.; Dionisi, C.; Dittmar, M.; Dominguez, A.; Doria, A.; Dova, M.T.; Duchesneau, D.; Dufournaud, D.; Duinker, P.; El Mamouni, H.; Engler, A.; Eppling, F.J.; Erne, F.C.; Ewers, A.; Extermann, P.; Fabre, M.; Falagan, M.A.; Falciano, S.; Favara, A.; Fay, J.; Fedin, O.; Felcini, M.; Ferguson, T.; Fesefeldt, H.; Fiandrini, E.; Field, J.H.; Filthaut, F.; Fisher, P.H.; Fisk, I.; Forconi, G.; Freudenreich, K.; Furetta, C.; Galaktionov, Iouri; Ganguli, S.N.; Garcia-Abia, Pablo; Gataullin, M.; Gau, S.S.; Gentile, S.; Gheordanescu, N.; Giagu, S.; Gong, Z.F.; Grenier, Gerald Jean; Grimm, O.; Gruenewald, M.W.; Guida, M.; van Gulik, R.; Gupta, V.K.; Gurtu, A.; Gutay, L.J.; Haas, D.; Hasan, A.; Hatzifotiadou, D.; Hebbeker, T.; Herve, Alain; Hidas, P.; Hirschfelder, J.; Hofer, H.; Holzner, G.; Hoorani, H.; Hou, S.R.; Hu, Y.; Iashvili, I.; Jin, B.N.; Jones, Lawrence W.; de Jong, P.; Josa-Mutuberria, I.; Khan, R.A.; Kafer, D.; Kaur, M.; Kienzle-Focacci, M.N.; Kim, D.; Kim, J.K.; Kirkby, Jasper; Kiss, D.; Kittel, W.; Klimentov, A.; Konig, A.C.; Kopal, M.; Kopp, A.; Koutsenko, V.; Kraber, M.; Kraemer, R.W.; Krenz, W.; Kruger, A.; Kunin, A.; Ladron de Guevara, P.; Laktineh, I.; Landi, G.; Lebeau, M.; Lebedev, A.; Lebrun, P.; Lecomte, P.; Lecoq, P.; Le Coultre, P.; Lee, H.J.; Le Goff, J.M.; Leiste, R.; Levtchenko, P.; Li, C.; Likhoded, S.; Lin, C.H.; Lin, W.T.; Linde, F.L.; Lista, L.; Liu, Z.A.; Lohmann, W.; Longo, E.; Lu, Y.S.; Lubelsmeyer, K.; Luci, C.; Luckey, David; Lugnier, L.; Luminari, L.; Lustermann, W.; Ma, W.G.; Maity, M.; Malgeri, L.; Malinin, A.; Mana, C.; Mangeol, D.; Mans, J.; Marian, G.; Martin, J.P.; Marzano, F.; Mazumdar, K.; McNeil, R.R.; Mele, S.; Merola, L.; Meschini, M.; Metzger, W.J.; von der Mey, M.; Mihul, A.; Milcent, H.; Mirabelli, G.; Mnich, J.; Mohanty, G.B.; Moulik, T.; Muanza, G.S.; Muijs, A.J.M.; Musicar, B.; Musy, M.; Napolitano, M.; Nessi-Tedaldi, F.; Newman, H.; Niessen, T.; Nisati, A.; Kluge, Hannelies; Ofierzynski, R.; Organtini, G.; Oulianov, A.; Palomares, C.; Pandoulas, D.; Paoletti, S.; Paolucci, P.; Paramatti, R.; Park, H.K.; Park, I.H.; Passaleva, G.; Patricelli, S.; Paul, Thomas Cantzon; Pauluzzi, M.; Paus, C.; Pauss, F.; Pedace, M.; Pensotti, S.; Perret-Gallix, D.; Petersen, B.; Piccolo, D.; Pierella, F.; Pieri, M.; Piroue, P.A.; Pistolesi, E.; Plyaskin, V.; Pohl, M.; Pojidaev, V.; Postema, H.; Pothier, J.; Prokofev, D.O.; Prokofiev, D.; Quartieri, J.; Rahal-Callot, G.; Rahaman, M.A.; Raics, P.; Raja, N.; Ramelli, R.; Rancoita, P.G.; Ranieri, R.; Raspereza, A.; Raven, G.; Razis, P.; Ren, D.; Rescigno, M.; Reucroft, S.; Riemann, S.; Riles, Keith; Rodin, J.; Roe, B.P.; Romero, L.; Rosca, A.; Rosier-Lees, S.; Roth, Stefan; Rosenbleck, C.; Roux, B.; Rubio, J.A.; Ruggiero, G.; Rykaczewski, H.; Saremi, S.; Sarkar, S.; Salicio, J.; Sanchez, E.; Sanders, M.P.; Schafer, C.; Schegelsky, V.; Schmidt-Kaerst, S.; Schmitz, D.; Schopper, H.; Schotanus, D.J.; Schwering, G.; Sciacca, C.; Seganti, A.; Servoli, L.; Shevchenko, S.; Shivarov, N.; Shoutko, V.; Shumilov, E.; Shvorob, A.; Siedenburg, T.; Son, D.; Smith, B.; Spillantini, P.; Steuer, M.; Stickland, D.P.; Stone, A.; Stoyanov, B.; Straessner, A.; Sudhakar, K.; Sultanov, G.; Sun, L.Z.; Sushkov, S.; Suter, H.; Swain, J.D.; Szillasi, Z.; Sztaricskai, T.; Tang, X.W.; Tauscher, L.; Taylor, L.; Tellili, B.; Teyssier, D.; Timmermans, Charles; Ting, Samuel C.C.; Ting, S.M.; Tonwar, S.C.; Toth, J.; Tully, C.; Tung, K.L.; Uchida, Y.; Ulbricht, J.; Valente, E.; Vesztergombi, G.; Vetlitsky, I.; Vicinanza, D.; Viertel, G.; Villa, S.; Vivargent, M.; Vlachos, S.; Vodopianov, I.; Vogel, H.; Vogt, H.; Vorobev, I.; Vorobov, A.A.; Vorvolakos, A.; Wadhwa, M.; Wallraff, W.; Wang, M.; Wang, X.L.; Wang, Z.M.; Weber, A.; Weber, M.; Wienemann, P.; Wilkens, H.; Wu, S.X.; Wynhoff, S.; Xia, L.; Xu, Z.Z.; Yamamoto, J.; Yang, B.Z.; Yang, C.G.; Yang, H.J.; Yang, M.; Ye, J.B.; Yeh, S.C.; Zalite, A.; Zalite, Yu.; Zhang, Z.P.; Zhu, G.Y.; Zhu, R.Y.; Zichichi, A.; Zilizi, G.; Zimmermann, B.; Zoller, M.

    2001-01-01

    The Standard Model Higgs boson is searched for in 233.2 pb-1 of data collected by the L3 detector at centre of mass energies from 192 GeV to 202 GeV. These data are consistent with the expectations of Standard Model processes and no evidence of a Higgs signal is observed. A lower limit on the mass of the Standard Model Higgs boson of 107.0 GeV is set at the 95% confidence level.

  1. GE will finance 614-MW cogeneration plant

    International Nuclear Information System (INIS)

    Anon.

    1990-01-01

    The General Electric Power Funding Corporation, a unit of GE Capital, will provide up to $870 million in construction and permanent financing, and letters of credit to Cogen Technologies of Houston, Texas. The agreement will fund the construction of a 614-megawatt (MW), combined-cycle cogeneration plant to be built in Linden, New Jersey, and for the purchase of gas properties. The plant will be owned by Cogen Technologies. The financing is one of the largest packages ever for a cogeneration plant, GE said

  2. Phase diagram of the Ge-rich of the Ba–Ge system and characterisation of single-phase BaGe4

    International Nuclear Information System (INIS)

    Prokofieva, Violetta K.; Pavlova, Lydia M.

    2014-01-01

    Highlights: • The Ba-Ge phase diagram for the range 50–100 at.% Ge was constructed. • Single-phase BaGe 4 grown by the Czochralski method was characterised. • A phenomenological model for a liquid-liquid phase transition is proposed. - Abstract: The Ba–Ge binary system has been investigated by several authors, but some uncertainties remain regarding phases with Ba/Ge ⩽ 2. The goal of this work was to resolve the uncertainty about the current phase diagram of Ba–Ge by performing DTA, X-ray powder diffraction, metallographic and chemical analyses, and measurements of the electrical conductivity and viscosity. The experimental Ba–Ge phase diagram over the composition range of 50–100 at.% Ge was constructed from the cooling curves and single-phase BaGe 4 grown by the Czochralski crystal pulling method was characterised. Semiconducting BaGe 4 crystallised peritectically from the liquid phase near the eutectic. In the liquid state, the caloric effects were observed in the DTA curves at 1050 °C where there are no definite phase lines in the Ba–Ge phase diagram. These effects are confirmed by significant changes in the viscosity and electrical conductivity of a Ba–Ge alloy with eutectic composition at this temperature. A phenomenological model based on two different approaches, a phase approach and a chemical approach, is proposed to explain the isothermal liquid–liquid phase transition observed in the Ba–Ge system from the Ge side. Our results suggest that this transition is due to the peritectic reactions in the liquid phase. This reversible phase transition results in the formation of precursors of various metastable clathrate phases and is associated with sudden changes in the structure of Ba–Ge liquid alloys. Characteristics of both first- and second-order phase transitions are observed. Charge transfer appears to play an important role in this transition

  3. Double stage crystallization of bulk Ge20Te80 glass

    International Nuclear Information System (INIS)

    Parthasarathy, G.; Bandyopadhyay, A.K.; Gopal, E.S.R.; Subbanna, G.N.

    1984-01-01

    The growing interest of the semiconducting glasses is partly because of their interesting electrical and optical properties. These properties are usually connected with their crystallization. In many glasses, the glass-supercooled liquid transition precedes crystallization. The glass transition temperature (Tsub(g)) is found to exhibit multistage processes for a few systems. In this communication, we report the observation of a double Tsub(g) effect in bulk Ge 20 Te 80 glass and also explain the structural changes taking place in the two stages. (author)

  4. Diamond turning of Si and Ge single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Blake, P.; Scattergood, R.O.

    1988-12-01

    Single-point diamond turning studies have been completed on Si and Ge crystals. A new process model was developed for diamond turning which is based on a critical depth of cut for plastic flow-to-brittle fracture transitions. This concept, when combined with the actual machining geometry for single-point turning, predicts that {open_quotes}ductile{close_quotes} machining is a combined action of plasticity and fracture. Interrupted cutting experiments also provide a meant to directly measure the critical depth parameter for given machining conditions.

  5. The microstructure investigation of GeTi thin film used for non-volatile memory

    International Nuclear Information System (INIS)

    Shen Jie; Liu Bo; Song Zhitang; Xu Cheng; Liang Shuang; Feng Songlin; Chen Bomy

    2008-01-01

    GeTi thin film has been found to have the reversible resistance switching property in our previous work. In this paper, the microstructure of this material with a given composition was investigated. The film was synthesized by magnetron sputtering and treated by the rapid temperature process. The results indicate a coexist status of amorphous and polycrystalline states in the as-deposited GeTi film, and the grains in the film are extremely fine. Furthermore, not until the film annealed at 600 deg. C, can the polycrystalline state be detected by X-ray diffraction. Based on the morphological analysis, the sputtered GeTi has the column growth tendency, and the column structure vanishes with the temperature increasing. The microstructure and thermal property analysis indicate that GeTi does not undergo evident phase change process during the annealing process, which makes the switching mechanism of GeTi different from that of chalcogenide memory material, the most widely used phase change memory material

  6. Mechanical characterization of poly-SiGe layers for CMOS–MEMS integrated application

    International Nuclear Information System (INIS)

    Modlinski, Robert; Witvrouw, Ann; Verbist, Agnes; De Wolf, Ingrid; Puers, Robert

    2010-01-01

    Measuring mechanical properties at the microscale is essential to understand and to fabricate reliable MEMS. In this paper a tensile testing system and matching microscale test samples are presented. The test samples have a dog-bone-like structure. They are designed to mimic standard macro-tensile test samples. The micro-tensile tests are used to characterize 0.9 µm thick polycrystalline silicon germanium (poly-SiGe) films. The poly-SiGe film, that can be considered as a close equivalent to polycrystalline silicon (poly-Si), is studied as a very promising material for use in CMOS/MEMS integration in a single chip due to its low-temperature LPCVD deposition (T < 450 °C). The fabrication process of the poly-SiGe micro-tensile test structure is explained in detail: the design, the processing and post-processing, the testing and finally the results' discussion. The poly-SiGe micro-tensile results are also compared with nanoindentation data obtained on the same poly-SiGe films as well as with results obtained by other research groups

  7. Mechanical characterization of poly-SiGe layers for CMOS-MEMS integrated application

    Science.gov (United States)

    Modlinski, Robert; Witvrouw, Ann; Verbist, Agnes; Puers, Robert; De Wolf, Ingrid

    2010-01-01

    Measuring mechanical properties at the microscale is essential to understand and to fabricate reliable MEMS. In this paper a tensile testing system and matching microscale test samples are presented. The test samples have a dog-bone-like structure. They are designed to mimic standard macro-tensile test samples. The micro-tensile tests are used to characterize 0.9 µm thick polycrystalline silicon germanium (poly-SiGe) films. The poly-SiGe film, that can be considered as a close equivalent to polycrystalline silicon (poly-Si), is studied as a very promising material for use in CMOS/MEMS integration in a single chip due to its low-temperature LPCVD deposition (T < 450 °C). The fabrication process of the poly-SiGe micro-tensile test structure is explained in detail: the design, the processing and post-processing, the testing and finally the results' discussion. The poly-SiGe micro-tensile results are also compared with nanoindentation data obtained on the same poly-SiGe films as well as with results obtained by other research groups.

  8. Investigation of microstructure and morphology for the Ge on porous silicon/Si substrate hetero-structure obtained by molecular beam epitaxy

    International Nuclear Information System (INIS)

    Gouder, S.; Mahamdi, R.; Aouassa, M.; Escoubas, S.; Favre, L.; Ronda, A.; Berbezier, I.

    2014-01-01

    cost growth process of relaxed Ge buffer layer. • The process was achieved using compliant porous silicon (PS) template layers. • Single crystal Ge layers have been deposited by molecular beam epitaxy on PS. • SiGe layers obtained are fully relaxed and present a high Ge content (0.74–0.96). • SiGe layers could be used as relaxed pseudosubstrate in microelectronic technology

  9. Preparation of special purity Ge - S - I and Ge - Se - I glasses

    Science.gov (United States)

    Velmuzhov, A. P.; Sukhanov, M. V.; Shiryaev, V. S.; Kotereva, T. V.; Snopatin, G. E.; Churbanov, M. F.

    2017-05-01

    The paper considers the new approaches for the production of special pure Ge - S - I and Ge - Se - I glasses via the germanium(IV) iodide, germanium(II) sulfide, as well as the Ge2S3, Ge2S3I2 and Ge2Se3I2 glassy alloys. The glass samples containing 0.03-0.17 ppm(wt) hydrogen impurity in the form of SH-group, 0.04-0.15 ppm(wt) hydrogen impurity in the form of SeH-group, and 0.5-7.8 ppm(wt) oxygen impurity in the form of Ge-O were produced. Using a crucible technique, the single-index [GeSe4]95I5 glass fibers of 300-400 μm diameter were drawn. The minimum optical losses in the best fiber were 1.7 dB/m at a wavelength of 5.5 μm; the background optical losses were within 2-3 dB/m in the spectral range of 2.5-8 μm.

  10. Molecules for materials: germanium hydride neutrals and anions. Molecular structures, electron affinities, and thermochemistry of GeHn/GeHn- (n = 0-4) and Ge2Hn/Ge2Hn(-) (n = 0-6).

    Science.gov (United States)

    Li, Qian-Shu; Lü, Rui-Hua; Xie, Yaoming; Schaefer, Henry F

    2002-12-01

    The GeH(n) (n = 0-4) and Ge(2)H(n) (n = 0-6) systems have been studied systematically by five different density functional methods. The basis sets employed are of double-zeta plus polarization quality with additional s- and p-type diffuse functions, labeled DZP++. For each compound plausible energetically low-lying structures were optimized. The methods used have been calibrated against a comprehensive tabulation of experimental electron affinities (Chemical Reviews 102, 231, 2002). The geometries predicted in this work include yet unknown anionic species, such as Ge(2)H(-), Ge(2)H(2)(-), Ge(2)H(3)(-), Ge(2)H(4)(-), and Ge(2)H(5)(-). In general, the BHLYP method predicts the geometries closest to the few available experimental structures. A number of structures rather different from the analogous well-characterized hydrocarbon radicals and anions are predicted. For example, a vinylidene-like GeGeH(2) (-) structure is the global minimum of Ge(2)H(2) (-). For neutral Ge(2)H(4), a methylcarbene-like HGë-GeH(3) is neally degenerate with the trans-bent H(2)Ge=GeH(2) structure. For the Ge(2)H(4) (-) anion, the methylcarbene-like system is the global minimum. The three different neutral-anion energy differences reported in this research are: the adiabatic electron affinity (EA(ad)), the vertical electron affinity (EA(vert)), and the vertical detachment energy (VDE). For this family of molecules the B3LYP method appears to predict the most reliable electron affinities. The adiabatic electron affinities after the ZPVE correction are predicted to be 2.02 (Ge(2)), 2.05 (Ge(2)H), 1.25 (Ge(2)H(2)), 2.09 (Ge(2)H(3)), 1.71 (Ge(2)H(4)), 2.17 (Ge(2)H(5)), and -0.02 (Ge(2)H(6)) eV. We also reported the dissociation energies for the GeH(n) (n = 1-4) and Ge(2)H(n) (n = 1-6) systems, as well as those for their anionic counterparts. Our theoretical predictions provide strong motivation for the further experimental study of these important germanium hydrides. Copyright 2002 Wiley

  11. Strain distribution of confined Ge/GeO2 core/shell nanoparticles engineered by growth environments

    Science.gov (United States)

    Wei, Wenyan; Yuan, Cailei; Luo, Xingfang; Yu, Ting; Wang, Gongping

    2016-02-01

    The strain distributions of Ge/GeO2 core/shell nanoparticles confined in different host matrix grown by surface oxidation are investigated. The simulated results by finite element method demonstrated that the strains of the Ge core and the GeO2 shell strongly depend on the growth environments of the nanoparticles. Moreover, it can be found that there is a transformation of the strain on Ge core from tensile to compressive strain during the growth of Ge/GeO2 core/shell nanoparticles. And, the transformation of the strain is closely related with the Young's modulus of surrounding materials of Ge/GeO2 core/shell nanoparticles.

  12. Thermal transport property of Ge34 and d-Ge investigated by molecular dynamics and the Slack's equation

    International Nuclear Information System (INIS)

    Han-Fu, Wang; Wei-Guo, Chu; Yan-Jun, Guo; Hao, Jin

    2010-01-01

    In this study, we evaluate the values of lattice thermal conductivity κ L of type II Ge clathrate (Ge 34 ) and diamond phase Ge crystal (d-Ge) with the equilibrium molecular dynamics (EMD) method and the Slack's equation. The key parameters of the Slack's equation are derived from the thermodynamic properties obtained from the lattice dynamics (LD) calculations. The empirical Tersoff's potential is used in both EMD and LD simulations. The thermal conductivities of d-Ge calculated by both methods are in accordance with the experimental values. The predictions of the Slack's equation are consistent with the EMD results above 250 K for both Ge 34 and d-Ge. In a temperature range of 200–1000 K, the κ L value of d-Ge is about several times larger than that of Ge 34 . (condensed matter: structure, thermal and mechanical properties)

  13. Ultra-smooth epitaxial Ge grown on Si(001) utilizing a thin C-doped Ge buffer layer

    KAUST Repository

    Mantey, J.

    2013-01-01

    Here, we present work on epitaxial Ge films grown on a thin buffer layer of C doped Ge (Ge:C). The growth rate of Ge:C is found to slow over time and is thus unsuitable for thick (>20 nm) layers. We demonstrate Ge films from 10 nm to >150 nm are possible by growing pure Ge on a thin Ge:C buffer. It is shown that this stack yields exceedingly low roughness levels (comparable to bulk Si wafers) and contains fewer defects and higher Hall mobility compared to traditional heteroepitaxial Ge. The addition of C at the interface helps reduce strain by its smaller atomic radius and its ability to pin defects within the thin buffer layer that do not thread to the top Ge layer. © 2013 AIP Publishing LLC.

  14. Interfacial sharpness and intermixing in a Ge-SiGe multiple quantum well structure

    Science.gov (United States)

    Bashir, A.; Gallacher, K.; Millar, R. W.; Paul, D. J.; Ballabio, A.; Frigerio, J.; Isella, G.; Kriegner, D.; Ortolani, M.; Barthel, J.; MacLaren, I.

    2018-01-01

    A Ge-SiGe multiple quantum well structure created by low energy plasma enhanced chemical vapour deposition, with nominal well thickness of 5.4 nm separated by 3.6 nm SiGe spacers, is analysed quantitatively using scanning transmission electron microscopy. Both high angle annular dark field imaging and electron energy loss spectroscopy show that the interfaces are not completely sharp, suggesting that there is some intermixing of Si and Ge at each interface. Two methods are compared for the quantification of the spectroscopy datasets: a self-consistent approach that calculates binary substitutional trends without requiring experimental or computational k-factors from elsewhere and a standards-based cross sectional calculation. Whilst the cross section approach is shown to be ultimately more reliable, the self-consistent approach provides surprisingly good results. It is found that the Ge quantum wells are actually about 95% Ge and that the spacers, whilst apparently peaking at about 35% Si, contain significant interdiffused Ge at each side. This result is shown to be not just an artefact of electron beam spreading in the sample, but mostly arising from a real chemical interdiffusion resulting from the growth. Similar results are found by use of X-ray diffraction from a similar area of the sample. Putting the results together suggests a real interdiffusion with a standard deviation of about 0.87 nm, or put another way—a true width defined from 10%-90% of the compositional gradient of about 2.9 nm. This suggests an intrinsic limit on how sharp such interfaces can be grown by this method and, whilst 95% Ge quantum wells (QWs) still behave well enough to have good properties, any attempt to grow thinner QWs would require modifications to the growth procedure to reduce this interdiffusion, in order to maintain a composition of ≥95% Ge.

  15. Magnetic behavior of Si-Ge bond in SixGe4-x nano-clusters

    Science.gov (United States)

    Nahali, Masoud; Mehri, Ali

    2018-06-01

    The structure of SixGe4-x nano-clusters were optimized by MPW1B95 level of theory using MG3S and SDB-aug-cc-PVTZ basis set. The agreement of the calculated ionization and dissociation energies with experimental values validates the reported structures of nano-clusters and justifies the use of hybrid meta density functional method. Since the Si-Si bond is stronger than Si-Ge and Ge-Ge bonds, the Si-Si, Si-Ge, and Ge-Ge diagonal bonds determine the precedence of the stability in these nano-clusters. The hybrid meta density functional calculations were carried out to investigate the adsorption of CO on all possible SixGe4-x nano-clusters. It was found that the silicon atom generally makes a stronger bond with CO than germanium and thereby preferentially affects the shape of structures having higher multiplicity. In Si-Ge structures with higher spin more than 95% of spins accumulate on positions with less bonds to other atoms of the cluster. Through CO adsorption on these clusters bridge structures are made that behave as spin bridge which conduct the spin from the nano-cluster surface to the adsorbate atoms. A better understanding of bridged structures was achieved upon introducing the 'spin bridge' concept. Based on exhaustive spin density analysis, it was found that the reason for the extra negative charge on oxygen in the bridged structures is the relocation of spin from the surface through the bridge.

  16. Si/SiGe heterointerfaces in one-, two-, and three-dimensional nanostructures: their impact on SiGe light emission

    Science.gov (United States)

    Lockwood, David; Wu, Xiaohua; Baribeau, Jean-Marc; Mala, Selina; Wang, Xialou; Tsybeskov, Leonid

    2016-03-01

    Fast optical interconnects together with an associated light emitter that are both compatible with conventional Si-based complementary metal-oxide- semiconductor (CMOS) integrated circuit technology is an unavoidable requirement for the next-generation microprocessors and computers. Self-assembled Si/Si1-xGex nanostructures, which can emit light at wavelengths within the important optical communication wavelength range of 1.3 - 1.55 μm, are already compatible with standard CMOS practices. However, the expected long carrier radiative lifetimes observed to date in Si and Si/Si1-xGex nanostructures have prevented the attainment of efficient light-emitting devices including the desired lasers. Thus, the engineering of Si/Si1-xGex heterostructures having a controlled composition and sharp interfaces is crucial for producing the requisite fast and efficient photoluminescence (PL) at energies in the range 0.8-0.9 eV. In this paper we assess how the nature of the interfaces between SiGe nanostructures and Si in heterostructures strongly affects carrier mobility and recombination for physical confinement in three dimensions (corresponding to the case of quantum dots), two dimensions (corresponding to quantum wires), and one dimension (corresponding to quantum wells). The interface sharpness is influenced by many factors such as growth conditions, strain, and thermal processing, which in practice can make it difficult to attain the ideal structures required. This is certainly the case for nanostructure confinement in one dimension. However, we demonstrate that axial Si/Ge nanowire (NW) heterojunctions (HJs) with a Si/Ge NW diameter in the range 50 - 120 nm produce a clear PL signal associated with band-to-band electron-hole recombination at the NW HJ that is attributed to a specific interfacial SiGe alloy composition. For three-dimensional confinement, the experiments outlined here show that two quite different Si1-xGex nanostructures incorporated into a Si0.6Ge0.4 wavy

  17. Results on decay with emission of two neutrinos or Majorons in Ge from GERDA Phase I

    Science.gov (United States)

    Agostini, M.; Allardt, M.; Bakalyarov, A. M.; Balata, M.; Barabanov, I.; Barros, N.; Baudis, L.; Bauer, C.; Becerici-Schmidt, N.; Bellotti, E.; Belogurov, S.; Belyaev, S. T.; Benato, G.; Bettini, A.; Bezrukov, L.; Bode, T.; Borowicz, D.; Brudanin, V.; Brugnera, R.; Budjáš, D.; Caldwell, A.; Cattadori, C.; Chernogorov, A.; D'Andrea, V.; Demidova, E. V.; di Vacri, A.; Domula, A.; Doroshkevich, E.; Egorov, V.; Falkenstein, R.; Fedorova, O.; Freund, K.; Frodyma, N.; Gangapshev, A.; Garfagnini, A.; Grabmayr, P.; Gurentsov, V.; Gusev, K.; Hegai, A.; Heisel, M.; Hemmer, S.; Heusser, G.; Hofmann, W.; Hult, M.; Inzhechik, L. V.; Csáthy, J. Janicskó; Jochum, J.; Junker, M.; Kazalov, V.; Kihm, T.; Kirpichnikov, I. V.; Kirsch, A.; Klimenko, A.; Knöpfle, K. T.; Kochetov, O.; Kornoukhov, V. N.; Kuzminov, V. V.; Laubenstein, M.; Lazzaro, A.; Lebedev, V. I.; Lehnert, B.; Liao, H. Y.; Lindner, M.; Lippi, I.; Lubashevskiy, A.; Lubsandorzhiev, B.; Lutter, G.; Macolino, C.; Majorovits, B.; Maneschg, W.; Medinaceli, E.; Misiaszek, M.; Moseev, P.; Nemchenok, I.; Palioselitis, D.; Panas, K.; Pandola, L.; Pelczar, K.; Pullia, A.; Riboldi, S.; Rumyantseva, N.; Sada, C.; Salathe, M.; Schmitt, C.; Schneider, B.; Schönert, S.; Schreiner, J.; Schütz, A.-K.; Schulz, O.; Schwingenheuer, B.; Selivanenko, O.; Shirchenko, M.; Simgen, H.; Smolnikov, A.; Stanco, L.; Stepaniuk, M.; Ur, C. A.; Vanhoefer, L.; Vasenko, A. A.; Veresnikova, A.; von Sturm, K.; Wagner, V.; Walter, M.; Wegmann, A.; Wester, T.; Wilsenach, H.; Wojcik, M.; Yanovich, E.; Zavarise, P.; Zhitnikov, I.; Zhukov, S. V.; Zinatulina, D.; Zuber, K.; Zuzel, G.

    2015-09-01

    A search for neutrinoless decay processes accompanied with Majoron emission has been performed using data collected during Phase I of the GERmanium Detector Array (GERDA) experiment at the Laboratori Nazionali del Gran Sasso of INFN (Italy). Processes with spectral indices were searched for. No signals were found and lower limits of the order of 10 yr on their half-lives were derived, yielding substantially improved results compared to previous experiments with Ge. A new result for the half-life of the neutrino-accompanied decay of Ge with significantly reduced uncertainties is also given, resulting in yr.

  18. Shallow acceptors in strained Ge/Ge1-xSix heterostructures with quantum wells

    International Nuclear Information System (INIS)

    Aleshkin, V.Ya.; Andreev, B.A.; Gavrilenko, V.I.; Erofeeva, I.V.; Kozlov, D.V.; Kuznetsov, O.A.

    2000-01-01

    Dependence of acceptor localized state energies in quantum wells (strained layers of Ge in heterostructures Ge/Ge 1-x Si x ) on the width of quantum well and position in it was studied theoretically. Spectrum of impurity absorption in the far infrared range was calculated. Comparison of the results calculated and observed photoconductivity spectra permits estimating acceptor distribution over quantum well and suggesting conclusion that acceptors can be largely concentrated near heteroboundaries. Absorption spectrum was calculated bearing in mind resonance impurity states, which permits explaining the observed specific features in the photoconductivity spectrum short-wave range by transition to resonance energy levels, bound to upper subzones of dimensional quantization [ru

  19. Isobaric analogue states of 73Ge via 72Ge(3He,d)73As reaction

    International Nuclear Information System (INIS)

    Ramaswamy, C.R.; Puttaswamy, N.G.; Sarma, N.

    1974-01-01

    The 72 Ge( 3 He,d) 73 As reaction has been studied at 20 MeV incident 3 He energy using an MP tandem and a multigap spectrograph. The energy spectrum of deuterons in the region between 9 to 10.5 MeV excitation energy of 73 As shows analogue states corresponding to G.S., 570, 673, 805, 900, 1050, and 1350 KeV states of 73 Ge. Angular distributions for the analogue states and 1-values of the transferred protons are extracted. The results are compared with available data on the levels of 73 Ge. (author)

  20. Templated self-assembly of SiGe quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Dais, Christian

    2009-08-19

    This PhD thesis reports on the fabrication and characterization of exact aligned SiGe quantum dot structures. In general, SiGe quantum dots which nucleate via the Stranski-Krastanov growth mode exhibit broad size dispersion and nucleate randomly on the surface. However, to tap the full potential of SiGe quantum dots it is necessary to control the positioning and size of the dots on a nanometer length, e.g. for electronically addressing of individual dots. This can be realized by so-called templated self-assembly, which combines top-down lithography with bottom-up selfassembly. In this process the lithographically defined pits serve as pre-defined nucleation points for the epitaxially grown quantum dots. In this thesis, extreme ultraviolet interference lithography at a wavelength of e=13.4 nm is employed for prepatterning of the Si substrates. This technique allows the precise and fast fabrication of high-resolution templates with a high degree of reproducibility. The subsequent epitaxial deposition is either performed by molecular beam epitaxy or low-pressure chemical vapour deposition. It is shown that the dot nucleation on pre-patterned substrates depends strongly on the lithography parameters, e.g. size and periodicity of the pits, as well as on the epitaxy parameters, e.g. growth temperature or material coverage. The interrelations are carefully analyzed by means of scanning force microscopy, transmission electron microscopy and X-ray diffraction measurements. Provided that correct template and overgrowth parameters are chosen, perfectly aligned and uniform SiGe quantum dot arrays of different period, size as well as symmetry are created. In particular, the quantum dot arrays with the so far smallest period (35 nm) and smallest size dispersion are fabricated in this thesis. Furthermore, the strain fields of the underlying quantum dots allow the fabrication of vertically aligned quantum dot stacks. Combining lateral and vertical dot alignment results in three

  1. The properties of Ge quantum rings deposited by pulsed laser deposition.

    Science.gov (United States)

    Ma, Xiying

    2010-07-01

    SiGe ring-shape nanostructures have attracted much research interest because of the interesting morphology, mechanical, and electromagnetic properties. In this paper, we present the planar Ge nanorings with well-defined sharp edges self-assembled on Si (100) matrix prepared with pulsed laser deposition (PLD) in the present of Ar gas. The transforming mechanism of the droplets is discussed, which a dynamic deformation model has been developed to simulate the self-transforming process of the droplets. The rings were found to be formed in two steps: from droplets to cones and from cones to rings via an elastic self-deforming process, which were likely to be driven by the lateral strain of Ge/Si layers and the surface tension.

  2. The ratio Rdp of the quasi-elastic nd → p(nn) to the elastic np → pn charge-exchange process yields at 0 deg over 0.55-2.0 GeV neutron beam energy region: 2. Comparison of the results with the model dependent calculations

    International Nuclear Information System (INIS)

    Sharov, V.I.; Morozov, A.A.; Shindin, R.A.; Chernykh, E.V.; Nomofilov, A.A.; Strunov, L.N.

    2008-01-01

    In our previous paper, the new experimental results on ratio R dp of the quasi-elastic charge-exchange yield at 0 Lab d eg for the nd → p + (nn) reaction to the elastic np → pn charge-exchange yield, were presented. The measurements were carried out at the Nuclotron of the Veksler and Baldin Laboratory of High Energies of the Joint Institute for Nuclear Research at the neutron beam kinetic energies of 0.55, 0.8, 1.0,1.2, 1.4, 1.8 and 2.0 GeV. In this paper, the comparison of these R dp data with the R dp calculations obtained within the impulse approximation by using the invariant amplitude sets from the GW/VPI phase-shift analysis, is made. The calculated R dp values with the set of invariant amplitude data for the elastic np → pn charge exchange at θ p,CM = 0 deg are in a good agreement with the experimental data. It has been confirmed that at θ p,CM = 0 deg the nd → pnn process is caused by the elastic np → pn charge-exchange reaction. Thus, it has been shown that the obtained experimental R dp results can be used for the Delta-Sigma experimental programme to reduce the total ambiguity in the extraction of the amplitude parts

  3. Effect of controlling recrystallization from the melt on the residual stress and structural properties of the Silica-clad Ge core fiber

    Science.gov (United States)

    Zhao, Ziwen; Cheng, Xueli; He, Ting; Xue, Fei; Zhang, Wei; Chen, Na; Wen, Jianxiang; Zeng, Xianglong; Wang, Tingyun

    2017-09-01

    Effect of controlling recrystallization from the melt (1000 °C) on the residual stress and structural properties of a Ge core fiber via molten core drawing (MCD) method is investigated. Ge core fibers is investigated using Raman spectroscopy, scanning electron microscope (SEM), and X-ray diffraction (XRD). Compared with the as-drawn Ge fiber, the Raman peak of the recrystallized Ge fiber shift from 300 cm-1 to 300.6 cm-1 and full width at half maximum (FWHM) decreased from 5.36 cm-1 to 4.48 cm-1. The Ge crystal grains which sizes are of 200-600 nm were formed during the process of recrystallization; the XRD peak of (1 1 1) plane is observed after recrystallization. These results show that controlling recrystallization allows the release of the thermal stress, and improvement of the crystal quality of Ge core.

  4. Shallow acceptors in Ge/GeSi heterostructures with quantum wells in magnetic field

    International Nuclear Information System (INIS)

    Aleshkin, V.Ya.; Antonov, A.V.; Veksler, D.B.; Gavrilenko, V.I.; Erofeeva, I.V.; Ikonnikov, A.V.; Kozlov, D.V.; Spirin, K.E.; Kuznetsov, O.A.

    2005-01-01

    One investigated both theoretically and experimentally into shallow acceptors in Ge/GeSi heterostructures with quantum wells (QW) in a magnetic field. It is shown that alongside with lines of cyclotron resonance in magnetoabsorption spectra one observes transitions from the ground state of acceptor to the excited ones associated with the Landau levels from the first and the second subbands of dimensional quantization, and resonance caused by ionization of A + -centres. To describe impurity transitions in Ge/GeSi heterostructures with QW in a magnetic field and to interpret the experiment results in detail one uses numerical method of calculation based on expansion of wave function of acceptor in terms of basis of wave functions of holes in QW in the absence of magnetic field [ru

  5. Ge interactions on HfO2 surfaces and kinetically driven patterning of Ge nanocrystals on HfO2

    International Nuclear Information System (INIS)

    Stanley, Scott K.; Joshi, Sachin V.; Banerjee, Sanjay K.; Ekerdt, John G.

    2006-01-01

    Germanium interactions are studied on HfO 2 surfaces, which are prepared through physical vapor deposition (PVD) and by atomic layer deposition. X-ray photoelectron spectroscopy and temperature-programed desorption are used to follow the reactions of germanium on HfO 2 . Germanium chemical vapor deposition at 870 K on HfO 2 produces a GeO x adhesion layer, followed by growth of semiconducting Ge 0 . PVD of 0.7 ML Ge (accomplished by thermally cracking GeH 4 over a hot filament) also produces an initial GeO x layer, which is stable up to 800 K. PVD above 2.0 ML deposits semiconducting Ge 0 . Temperature programed desorption experiments of ∼1.0 ML Ge from HfO 2 at 400-1100 K show GeH 4 desorption below 600 K and GeO desorption above 850 K. These results are compared to Ge on SiO 2 where GeO desorption is seen at 550 K. Exploiting the different reactivity of Ge on HfO 2 and SiO 2 allows a kinetically driven patterning scheme for high-density Ge nanoparticle growth on HfO 2 surfaces that is demonstrated

  6. X-ray electron spectra of chalcogenide glasses and polycrystalline alloys of Ge-Te and As-Te systems

    International Nuclear Information System (INIS)

    Panus, V.R.

    1990-01-01

    Comparative investigation into structures of crystals and glasses in Ge-Te and As-Te two-component systems was conducted. Analysis of x-ray electron spectra of Ge-Te and As-Te systems indicates, that processes of dissociation-association resulting in formation of new structure units occur in telluride melts at synthesis temperatures. Structural chemical composition of binary glass-like alloys of Ge-Te and As-Te systems differs essentially from the one that corresponds to fusibility equilibrium curve. Oxygen doping into tellurium-base glasses results mainly in occurence of structures forecasted due to thermochemical calculation

  7. Tailoring the spin polarization in Ge/SiGe multiple quantum wells

    International Nuclear Information System (INIS)

    Giorgioni, Anna; Pezzoli, Fabio; Gatti, Eleonora; Grilli, Emanuele; Guzzi, Mario; Bottegoni, Federico; Cecchi, Stefano; Ciccacci, Franco; Isella, Giovanni; Trivedi, Dhara; Song, Yang; Li, Pengki; Dery, Hanan

    2013-01-01

    We performed spin-resolved photoluminescence measurements on Ge/SiGe multiple quantum wells with different well thickness and using different exciting power densities. The polarization of the direct emission strongly depends on the relative weight of electrons photoexcited from the light and the heavy hole subbands. The study of the polarization as a function of the exciting power highlights the role of the carrier-carrier interactions in determining spin depolarization

  8. Thin SiGe virtual substrates for Ge heterostructures integration on silicon

    International Nuclear Information System (INIS)

    Cecchi, S.; Chrastina, D.; Frigerio, J.; Isella, G.; Gatti, E.; Guzzi, M.; Müller Gubler, E.; Paul, D. J.

    2014-01-01

    The possibility to reduce the thickness of the SiGe virtual substrate, required for the integration of Ge heterostructures on Si, without heavily affecting the crystal quality is becoming fundamental in several applications. In this work, we present 1 μm thick Si 1−x Ge x buffers (with x > 0.7) having different designs which could be suitable for applications requiring a thin virtual substrate. The rationale is to reduce the lattice mismatch at the interface with the Si substrate by introducing composition steps and/or partial grading. The relatively low growth temperature (475 °C) makes this approach appealing for complementary metal-oxide-semiconductor integration. For all the investigated designs, a reduction of the threading dislocation density compared to constant composition Si 1−x Ge x layers was observed. The best buffer in terms of defects reduction was used as a virtual substrate for the deposition of a Ge/SiGe multiple quantum well structure. Room temperature optical absorption and photoluminescence analysis performed on nominally identical quantum wells grown on both a thick graded virtual substrate and the selected thin buffer demonstrates a comparable optical quality, confirming the effectiveness of the proposed approach

  9. Temperature dependence of the interband critical points of bulk Ge and strained Ge on Si

    Science.gov (United States)

    Fernando, Nalin S.; Nunley, T. Nathan; Ghosh, Ayana; Nelson, Cayla M.; Cooke, Jacqueline A.; Medina, Amber A.; Zollner, Stefan; Xu, Chi; Menendez, Jose; Kouvetakis, John

    2017-11-01

    Epitaxial Ge layers on a Si substrate experience a tensile biaxial stress due to the difference between the thermal expansion coefficients of the Ge epilayer and the Si substrate, which can be measured using asymmetric X-ray diffraction reciprocal space maps. This stress depends on temperature and affects the band structure, interband critical points, and optical spectra. This manuscripts reports careful measurements of the temperature dependence of the dielectric function and the interband critical point parameters of bulk Ge and Ge epilayers on Si using spectroscopic ellipsometry from 80 to 780 K and from 0.8 to 6.5 eV. The authors find a temperature-dependent redshift of the E1 and E1 + Δ1 critical points in Ge on Si (relative to bulk Ge). This redshift can be described well with a model based on thermal expansion coefficients, continuum elasticity theory, and the deformation potential theory for interband transitions. The interband transitions leading to E0‧ and E2 critical points have lower symmetry and therefore are not affected by the stress.

  10. High-pressure structural behavior of nanocrystalline Ge

    DEFF Research Database (Denmark)

    Wang, H.; Liu, J. F.; Yan, H.

    2007-01-01

    The equation of state and the pressure of the I-II transition have been studied for nanocrystalline Ge using synchrotron x-ray diffraction. The bulk modulus and the transition pressure increase with decreasing particle size for both Ge-I and Ge-II, but the percentage volume collapse at the transi...

  11. P-barp and pp elastic scattering from 10 GeV to 1000 GeV centre-of-mass energy

    International Nuclear Information System (INIS)

    Islam, M.M.; Fearnley, T.; Guillaud, J.P.

    1984-01-01

    Antiproton-proton and proton-proton elastic scattering are studied simultaneously over the energy range √s approx. (10-1000) GeV in a nucleon valence core model proposed earlier. The scattering is described as primarily due to two processes: diffraction and hard scattering. The latter originates from the scattering of a nucleon core off another core. Destructive interference between the two processes produces dips in p-barp and pp differential cross-sections. As energy increases beyond the ISR range (√s = (23-62) GeV), the dips get filled up, and eventually transform into shoulders or breaks at collider energies. Differences between p-barp and pp differential cross-sections persist even at collider energies. Comparison with ISR data shows that the model provides a quantitative description of pp elastic scattering in this energy range. Predictions of p-barp and pp differential cross-sections at future collider energies √s = 800 and 2000 GeV are given. In order to distinguish between competing models, need for measuring the p-barp differential cross-section at the ISR and SPS collider in the abs (t)-range (0.5-2.0) (GeV) 2 is stressed

  12. anti pp and pp elastic scattering from 10 GeV to 1000 GeV centre-of-mass energy

    Energy Technology Data Exchange (ETDEWEB)

    Islam, M.M. (Connecticut Univ., Storrs (USA). Dept. of Physics); Fearnley, T. (University Coll., London (UK). Dept. of Physics and Astronomy); Guillaud, J.P. (Grenoble-1 Univ., 74 - Annecy (France). Lab. de Physique des Particules)

    1984-06-21

    Antiproton-proton and proton-proton elastic scattering are studied simultaneously over the energy range ..sqrt..anti s approx.= (10/1000) GeV in a nucleon valence core model proposed earlier. The scattering is described as primarily due to two processes: diffraction and hard scattering. The latter originates from the scattering of a nucleon core off another core. Destructive interference between the two processes produces dips in anti pp and pp differential cross-sections. As energy increases beyond the ISR range (..sqrt..anti s = (23/62) GeV), the dips get filled up, and eventually transform into shoulders or breaks at collider energies. Differences between anti pp and pp differential cross-sections persist even at collider energies. Comparison with ISR data shows that the model provides a quantitative description of pp elastic scattering in this energy range. Predictions of anti pp and pp differential cross-sections at future collider energies ..sqrt..s = 800 and 2000 GeV are given. In order to distinguish between competing models, need for measuring the anti pp differential cross-section at the ISR and SPS collider in the vertical stroketvertical stroke-range (0.5/2.0) (GeV)/sup 2/ is stressed.

  13. P-barp and pp elastic scattering from 10 GeV to 1000 GeV centre-of-mass energy

    Energy Technology Data Exchange (ETDEWEB)

    Islam, M.M. (Connecticut Univ., Storrs (USA). Dept. of Physics); Fearnley, T. (University Coll., London (UK). Dept. of Physics and Astronomy); Guillaud, J.P. (L.A.P.P. - BP909, 74019 Annecy-Le-Vieux Cedex, France)

    1984-06-21

    Antiproton-proton and proton-proton elastic scattering are studied simultaneously over the energy range ..sqrt..s approx. (10-1000) GeV in a nucleon valence core model proposed earlier. The scattering is described as primarily due to two processes: diffraction and hard scattering. The latter originates from the scattering of a nucleon core off another core. Destructive interference between the two processes produces dips in p-barp and pp differential cross-sections. As energy increases beyond the ISR range (..sqrt..s = (23-62) GeV), the dips get filled up, and eventually transform into shoulders or breaks at collider energies. Differences between p-barp and pp differential cross-sections persist even at collider energies. Comparison with ISR data shows that the model provides a quantitative description of pp elastic scattering in this energy range. Predictions of p-barp and pp differential cross-sections at future collider energies ..sqrt..s = 800 and 2000 GeV are given. In order to distinguish between competing models, need for measuring the p-barp differential cross-section at the ISR and SPS collider in the abs (t)-range (0.5-2.0) (GeV)/sup 2/ is stressed.

  14. Giant magnetocaloric effect in isostructural MnNiGe-CoNiGe system by establishing a Curie-temperature window

    KAUST Repository

    Liu, E. K.; Zhang, H. G.; Xu, G. Z.; Zhang, X. M.; Ma, R. S.; Wang, W. H.; Chen, J. L.; Zhang, H. W.; Wu, G. H.; Feng, L.; Zhang, Xixiang

    2013-01-01

    An effective scheme of isostructural alloying was applied to establish a Curie-temperature window in isostructural MnNiGe-CoNiGe system. With the simultaneous accomplishment of decreasing structural-transition temperature and converting

  15. Microstructure evolution in pulsed laser deposited epitaxial Ge-Sb-Te chalcogenide thin films

    Energy Technology Data Exchange (ETDEWEB)

    Ross, Ulrich; Lotnyk, Andriy, E-mail: andriy.lotnyk@iom-leipzig.de; Thelander, Erik; Rauschenbach, Bernd

    2016-08-15

    The thin film deposition and structure of highly oriented telluride compounds is of particular interest for phase-change applications in next-generation non-volatile memory such as heterostructure designs, as well as for the investigation of novel optical, thermoelectric and ferroelectric properties in layered telluride compounds. In this work, epitaxial Ge-Sb-Te thin films were successfully produced by pulsed laser deposition on silicon with and without amorphous SiO{sub x} interlayer at elevated process temperatures from a Ge{sub 2}Sb{sub 2}Te{sub 5} target. Aberration-corrected high-resolution scanning transmission electron microscopy (STEM) imaging reveals a distinct interface configuration of the trigonal phase connected by a quasi van der Waals gap (vacancy) to the Sb/Te-passivated single crystalline Si substrate, yet also an intermediate textured growth regime in which the substrate symmetry is only weakly coupled to the thin film orientation, as well as strong deviation of composition at high deposition temperatures. Textured growth of Ge-Sb-Te thin film was also observed on SiO{sub x}/Si substrate with no evidence of an intermediate Sb/Te surface layer on top of an SiO{sub x} layer. In addition, particular defect structures formed by local reorganization of the stacking sequence across the vacancy gap are observed and appear to be intrinsic to these van der Waals-layered compounds. Theoretical image simulations of preferred stacking sequences can be matched to individual building blocks in the Ge-Sb-Te grain. - Highlights: • Atomic-resolution Cs-corrected STEM imaging of PLD deposited Ge-Sb-Te thin films. • Changing of overall composition with increasing deposition temperature. • Direct imaging of surface passivation Sb/Te layer at the Ge-Sb-Te/Si(111) interface. • The Sb/Te passivation layer is not a prerequisite for highly oriented growth of Ge-Sb-Te thin films.

  16. Catalyst engineering for lithium ion batteries: the catalytic role of Ge in enhancing the electrochemical performance of SnO2(GeO2)0.13/G anodes.

    Science.gov (United States)

    Zhu, Yun Guang; Wang, Ye; Han, Zhao Jun; Shi, Yumeng; Wong, Jen It; Huang, Zhi Xiang; Ostrikov, Kostya Ken; Yang, Hui Ying

    2014-12-21

    The catalytic role of germanium (Ge) was investigated to improve the electrochemical performance of tin dioxide grown on graphene (SnO(2)/G) nanocomposites as an anode material of lithium ion batteries (LIBs). Germanium dioxide (GeO(20) and SnO(2) nanoparticles (GeO(2))0.13/G nanocomposites can deliver a capacity of 1200 mA h g(-1) at a current density of 100 mA g(-1), which is much higher than the traditional theoretical specific capacity of such nanocomposites (∼ 702 mA h g(-1)). More importantly, the SnO(2)(GeO(2))0.13/G nanocomposites exhibited an improved rate, large current capability (885 mA h g(-1) at a discharge current of 2000 mA g(-1)) and excellent long cycling stability (almost 100% retention after 600 cycles). The enhanced electrochemical performance was attributed to the catalytic effect of Ge, which enabled the reversible reaction of metals (Sn and Ge) to metals oxide (SnO(2) and GeO(2)) during the charge/discharge processes. Our demonstrated approach towards nanocomposite catalyst engineering opens new avenues for next-generation high-performance rechargeable Li-ion batteries anode materials.

  17. Deeply virtual compton scattering at 6 GeV

    International Nuclear Information System (INIS)

    Berthot, J.; Chen, J.P.; Chudakov, E.

    2000-01-01

    We propose a measurement of the Deep Virtual Compton Scattering process (DVCS) ep → epγ in Hall A at Jefferson Lab with a 6 GeV beam. We are able to explore the onset of Q 2 scaling, by measuring a beam helicity asymmetry for Q 2 ranging from 1.5 to 2.5 GeV 2 at x B ∼0.35. At this kinematics, the asymmetry is dominated by the DVCS - Bethe-Heitler (BH) interference, which is proportional to the imaginary part of the DVCS amplitude amplified by the full magnitude of the BH amplitude. The imaginary part of the DVCS amplitude is expected to scale early. Indeed, the imaginary part of the forward Compton amplitude measured in deep inelastic scattering (via the optical theorem) scales at Q 2 as low as 1 GeV 2 . If the scaling regime is reached, we will make an 8% measurement of the skewed parton distributions (SPD) contributing to the DVCS amplitude. Also, this experiment allows us to separately estimate the size of the higher-twist effects, since they are only suppressed by an additional factor 1/Q compared to the leading-twist term, and have a different angular dependence. We use a polarized electron beam and detect the scattered electron in the HRSe, the real photon in an electromagnetic calorimeter (under construction) and the recoil proton in a shielded scintillator array (to be constructed). This allows as to determine the difference in cross-sections for electrons of opposite helicities. This observable is directly linked to the SPD's. We estimate that 25 days of beam (600 hours) are needed to achieve this goal. (authors)

  18. Deeply virtual compton scattering at 6 GeV

    Energy Technology Data Exchange (ETDEWEB)

    Berthot, J. [Universite Blaise Pascal, Clermont-Ferrand II, Lab. de Physique Corpusculaire (CNRS), 63 - Aubiere (France); Chen, J.P.; Chudakov, E. [National Accelerator Facility, Newport News, Virginia (United States)] [and others

    2000-07-01

    We propose a measurement of the Deep Virtual Compton Scattering process (DVCS) ep {yields} ep{gamma} in Hall A at Jefferson Lab with a 6 GeV beam. We are able to explore the onset of Q{sup 2} scaling, by measuring a beam helicity asymmetry for Q{sup 2} ranging from 1.5 to 2.5 GeV{sup 2} at x{sub B}{approx}0.35. At this kinematics, the asymmetry is dominated by the DVCS - Bethe-Heitler (BH) interference, which is proportional to the imaginary part of the DVCS amplitude amplified by the full magnitude of the BH amplitude. The imaginary part of the DVCS amplitude is expected to scale early. Indeed, the imaginary part of the forward Compton amplitude measured in deep inelastic scattering (via the optical theorem) scales at Q{sup 2} as low as 1 GeV{sup 2}. If the scaling regime is reached, we will make an 8% measurement of the skewed parton distributions (SPD) contributing to the DVCS amplitude. Also, this experiment allows us to separately estimate the size of the higher-twist effects, since they are only suppressed by an additional factor 1/Q compared to the leading-twist term, and have a different angular dependence. We use a polarized electron beam and detect the scattered electron in the HRSe, the real photon in an electromagnetic calorimeter (under construction) and the recoil proton in a shielded scintillator array (to be constructed). This allows as to determine the difference in cross-sections for electrons of opposite helicities. This observable is directly linked to the SPD's. We estimate that 25 days of beam (600 hours) are needed to achieve this goal. (authors)

  19. Fabrication of PureGaB Ge-on-Si photodiodes for well-controlled 100-pA-level dark currents

    NARCIS (Netherlands)

    Sammak, A.; Aminian, M.; Qi, L.; De Boer, W.B.; Charbon, E.; Nanver, L.K.

    2014-01-01

    The selective epitaxial growth of Ge-on-Si followed by in-situ deposition of a nm-thin Ga/B layer stack (PureGaB) has previously been shown to be a robust CMOS-compatible process for fabrication of Ge-on-Si photodiodes. In this paper, strategies to improve the control and reproducibility of PureGaB

  20. Structural, Dynamic, and Vibrational Properties during Heat Transfer in Si/Ge Superlattices: A Car-Parrinello Molecular Dynamics Study

    OpenAIRE

    Ji, Pengfei; Zhang, Yuwen; Yang, Mo

    2016-01-01

    The structural, dynamic, and vibrational properties during the heat transfer process in Si/Ge superlattices, are studied by analyzing the trajectories generated by the ab initio Car-Parrinello molecular dynamics simulation. The radial distribution functions and mean square displacements are calculated and further discussions are made to explain and probe the structural changes relating to the heat transfer phenomenon. Furthermore, the vibrational density of states of the two layers (Si/Ge) ar...

  1. Ge-rich graded-index Si1-xGex devices for MID-IR integrated photonics

    Science.gov (United States)

    Ramirez, J. M.; Vakarin, V.; Liu, Q.; Frigerio, J.; Ballabio, A.; Le Roux, X.; Benedikovic, D.; Alonso-Ramos, C.; Isella, G.; Vivien, L.; Marris-Morini, D.

    2018-02-01

    Mid-infrared (mid-IR) silicon photonics is becoming a prominent research with remarkable potential in several applications such as in early medical diagnosis, safe communications, imaging, food safety and many more. In the quest for the best material platform to develop new photonic systems, Si and Ge depart with a notable advantage over other materials due to the high processing maturity accomplished during the last part of the 20th century through the deployment of the CMOS technology. From an optical viewpoint, combining Si with Ge to obtain SiGe alloys with controlled stoichiometry is also of interest for the photonic community since permits to increase the effective refractive index and the nonlinear parameter, providing a fascinating playground to exploit nonlinear effects. Furthermore, using Ge-rich SiGe gives access to a range of deep mid-IR wavelengths otherwise inaccessible (λ 2-20 μm). In this paper, we explore for the first time the limits of this approach by measuring the spectral loss characteristic over a broadband wavelength range spanning from λ = 5.5 μm to 8.5 μm. Three different SiGe waveguide platforms are compared, each one showing higher compactness than the preceding through the engineering of the vertical Ge profile, giving rise to different confinement characteristics to the propagating modes. A flat propagation loss characteristic of 2-3 dB/cm over the entire wavelength span is demonstrated in Ge-rich graded-index SiGe waveguides of only 6 μm thick. Also, the role of the overlap fraction of the confined optical mode with the Si-rich area at the bottom side of the epitaxial SiGe waveguide is put in perspective, revealing a lossy characteristic compared to the other designs were the optical mode is located in the Ge-rich area at the top of the waveguide uniquely. These Ge-rich graded-index SiGe waveguides may pave the way towards a new generation of photonic integrated circuits operating at deep mid-IR wavelengths.

  2. Effect of ultrathin GeOx interfacial layer formed by thermal oxidation on Al2O3 capped Ge

    International Nuclear Information System (INIS)

    Han Le; Zhang Xiong; Wang Sheng-Kai; Xue Bai-Qing; Liu Hong-Gang; Wu Wang-Ran; Zhao Yi

    2014-01-01

    We propose a modified thermal oxidation method in which an Al 2 O 3 capping layer is used as an oxygen blocking layer (OBL) to form an ultrathin GeO x interfacial layer, and obtain a superior Al 2 O 3 /GeO x /Ge gate stack. The GeO x interfacial layer is formed in oxidation reaction by oxygen passing through the Al 2 O 3 OBL, in which the Al 2 O 3 layer could restrain the oxygen diffusion and suppress the GeO desorption during thermal treatment. The thickness of the GeO x interfacial layer would dramatically decrease as the thickness of Al 2 O 3 OBL increases, which is beneficial to achieving an ultrathin GeO x interfacial layer to satisfy the demand for small equivalent oxide thickness (EOT). In addition, the thickness of the GeO x interfacial layer has little influence on the passivation effect of the Al 2 O 3 /Ge interface. Ge (100) p-channel metal–oxide–semiconductor field-effect transistors (pMOSFETs) using the Al 2 O 3 /GeO x /Ge gate stacks exhibit excellent electrical characteristics; that is, a drain current on-off (I on /I off ) ratio of above 1×10 4 , a subthreshold slope of ∼ 120 mV/dec, and a peak hole mobility of 265 cm 2 /V·s are achieved. (condensed matter: structural, mechanical, and thermal properties)

  3. Photoreflectance Spectroscopy Characterization of Ge/Si0.16Ge0.84 Multiple Quantum Wells on Ge Virtual Substrate

    Directory of Open Access Journals (Sweden)

    Hung-Pin Hsu

    2013-01-01

    Full Text Available We report a detailed characterization of a Ge/Si0.16Ge0.84 multiple quantum well (MQW structure on Ge-on-Si virtual substrate (VS grown by ultrahigh vacuum chemical vapor deposition by using temperature-dependent photoreflectance (PR in the temperature range from 10 to 300 K. The PR spectra revealed a wide range of optical transitions from the MQW region as well as transitions corresponding to the light-hole and heavy-hole splitting energies of Ge-on-Si VS. A detailed comparison of PR spectral line shape fits and theoretical calculation led to the identification of various quantum-confined interband transitions. The temperature-dependent PR spectra of Ge/Si0.16Ge0.84 MQW were analyzed using Varshni and Bose-Einstein expressions. The parameters that describe the temperature variations of various quantum-confined interband transition energies were evaluated and discussed.

  4. Electronic structure of Ge-2 and Ge-2 and thermodynamic properties of Ge-2 from all electron ab initio investigations and Knudsen effusion mass spectroscopic measurements

    DEFF Research Database (Denmark)

    Shim, Irene; Baba, M. Sai; Gingerich, K.A.

    2002-01-01

    The low-lying states of the molecule Ge-2 and of the ion Ge-2(-) have been investigated by all electron ab initio multiconfiguration self-consistent field (CASSCF) and multi-reference configuration interaction (MRCI) calculations. The relativistic corrections for the Darwin contact term and for t......The low-lying states of the molecule Ge-2 and of the ion Ge-2(-) have been investigated by all electron ab initio multiconfiguration self-consistent field (CASSCF) and multi-reference configuration interaction (MRCI) calculations. The relativistic corrections for the Darwin contact term...... excited states are presented. Thermal functions based on the theoretically determined molecular parameters were used to derive the thermodynamic properties of the Ge-2 molecule from new mass spectrometric equilibrium data. The literature value for the dissociation energy of Ge-2 has been re...

  5. Higgs Candidates in $e^+ e^-$ Interactions at $\\sqrt{s}$= 206.6 GeV

    CERN Document Server

    Acciarri, M; Adriani, O; Aguilar-Benítez, M; Alcaraz, J; Alemanni, G; Allaby, James V; Aloisio, A; Alviggi, M G; Ambrosi, G; Anderhub, H; Andreev, V P; Angelescu, T; Anselmo, F; Arefev, A; Azemoon, T; Aziz, T; Bagnaia, P; Bajo, A; Baksay, L; Balandras, A; Baldew, S V; Todorova-Nová, S; Banerjee, Sw; Barczyk, A; Barillère, R; Bartalini, P; Basile, M; Batalova, N; Battiston, R; Bay, A; Becattini, F; Becker, U; Behner, F; Bellucci, L; Berbeco, R; Berdugo, J; Berges, P; Bertucci, B; Betev, B L; Bhattacharya, S; Biasini, M; Biland, A; Blaising, J J; Blyth, S C; Bobbink, Gerjan J; Böhm, A; Boldizsar, L; Borgia, B; Bourilkov, D; Bourquin, Maurice; Braccini, S; Branson, J G; Brochu, F; Buffini, A; Buijs, A; Burger, J D; Burger, W J; Cai, X D; Capell, M; Cara Romeo, G; Carlino, G; Cartacci, A M; Casaus, J; Castellini, G; Cavallari, F; Cavallo, N; Cecchi, C; Cerrada-Canales, M; Cesaroni, F; Chamizo-Llatas, M; Chang, Y H; Chaturvedi, U K; Chemarin, M; Chen, A; Chen, G; Chen, G M; Chen, H F; Chen, H S; Chiefari, G; Cifarelli, Luisa; Cindolo, F; Civinini, C; Clare, I; Clare, R; Coignet, G; Colino, N; Costantini, S; Cotorobai, F; de la Cruz, B; Csilling, Akos; Cucciarelli, S; Dai, T S; van Dalen, J A; D'Alessandro, R; De Asmundis, R; Déglon, P L; Degré, A; Deiters, K; Della Volpe, D; Delmeire, E; Denes, P; De Notaristefani, F; De Salvo, A; Diemoz, M; Dierckxsens, M; Van Dierendonck, D N; Dionisi, C; Dittmar, Michael; Dominguez, A; Doria, A; Dova, M T; Duchesneau, D; Dufournaud, D; Duinker, P; Durán, I; El-Mamouni, H; Engler, A; Eppling, F J; Erné, F C; Ewers, A; Extermann, Pierre; Fabre, M; Falagán, M A; Falciano, S; Favara, A; Fay, J; Fedin, O; Felcini, Marta; Ferguson, T; Fesefeldt, H S; Fiandrini, E; Field, J H; Filthaut, Frank; Fisher, P H; Fisk, I; Forconi, G; Freudenreich, Klaus; Furetta, C; Galaktionov, Yu; Ganguli, S N; García-Abia, P; Gataullin, M; Gau, S S; Gentile, S; Gheordanescu, N; Giagu, S; Gong, Z F; Grenier, G; Grimm, O; Grünewald, M W; Guida, M; van Gulik, R; Gupta, V K; Gurtu, A; Gutay, L J; Haas, D; Hasan, A; Hatzifotiadou, D; Hebbeker, T; Hervé, A; Hidas, P; Hirschfelder, J; Hofer, H; Holzner, G; Hoorani, H; Hou, S R; Hu, Y; Iashvili, I; Jin, B N; Jones, L W; de Jong, P; Josa-Mutuberria, I; Khan, R A; Käfer, D; Kaur, M; Kienzle-Focacci, M N; Kim, D; Kim, J K; Kirkby, Jasper; Kiss, D; Kittel, E W; Klimentov, A; König, A C; Kopal, M; Kopp, A; Koutsenko, V F; Kräber, M H; Krämer, R W; Krenz, W; Krüger, A; Kunin, A; Ladrón de Guevara, P; Laktineh, I; Landi, G; Lebeau, M; Lebedev, A; Lebrun, P; Lecomte, P; Lecoq, P; Le Coultre, P; Lee, H J; Le Goff, J M; Leiste, R; Levchenko, P M; Li Chuan; Likhoded, S A; Lin, C H; Lin, W T; Linde, Frank L; Lista, L; Liu, Z A; Lohmann, W; Longo, E; Lü, Y S; Lübelsmeyer, K; Luci, C; Luckey, D; Lugnier, L; Luminari, L; Lustermann, W; Ma Wen Gan; Maity, M; Malgeri, L; Malinin, A; Maña, C; Mangeol, D J J; Mans, J; Marian, G; Martin, J P; Marzano, F; Mazumdar, K; McNeil, R R; Mele, S; Merola, L; Meschini, M; Metzger, W J; Von der Mey, M; Mihul, A; Milcent, H; Mirabelli, G; Mnich, J; Mohanty, G B; Moulik, T; Muanza, G S; Muijs, A J M; Musicar, B; Musy, M; Napolitano, M; Nessi-Tedaldi, F; Newman, H; Niessen, T; Nisati, A; Nowak, H; Ofierzynski, R A; Organtini, G; Oulianov, A; Palomares, C; Pandoulas, D; Paoletti, S; Paolucci, P; Paramatti, R; Park, H K; Park, I H; Passaleva, G; Patricelli, S; Paul, T; Pauluzzi, M; Paus, C; Pauss, Felicitas; Pedace, M; Pensotti, S; Perret-Gallix, D; Petersen, B; Piccolo, D; Pierella, F; Pieri, M; Piroué, P A; Pistolesi, E; Plyaskin, V; Pohl, M; Pozhidaev, V; Postema, H; Pothier, J; Prokofiev, D O; Prokofev, D; Quartieri, J; Rahal-Callot, G; Rahaman, M A; Raics, P; Raja, N; Ramelli, R; Rancoita, P G; Ranieri, R; Raspereza, A V; Raven, G; Razis, P A; Ren, D; Rescigno, M; Reucroft, S; Riemann, S; Riles, K; Rodin, J; Roe, B P; Romero, L; Rosca, A; Rosier-Lees, S; Roth, S; Rosenbleck, C; Rubio, Juan Antonio; Ruggiero, G; Rykaczewski, H; Saremi, S; Sarkar, S; Salicio, J; Sánchez, E; Sanders, M P; Schäfer, C; Shchegelskii, V; Schmidt-Kärst, S; Schmitz, D; Schopper, Herwig Franz; Schotanus, D J; Schwering, G; Sciacca, C; Seganti, A; Servoli, L; Shevchenko, S; Shivarov, N; Shoutko, V; Shumilov, E; Shvorob, A V; Siedenburg, T; Son, D; Smith, B; Spillantini, P; Steuer, M; Stickland, D P; Stone, A; Stoyanov, B; Strässner, A; Sudhakar, K; Sultanov, G G; Sun, L Z; Sushkov, S V; Suter, H; Swain, J D; Szillási, Z; Sztaricskai, T; Tang, X W; Tauscher, Ludwig; Taylor, L; Tellili, B; Timmermans, C; Ting, Samuel C C; Ting, S M; Tonwar, S C; Tóth, J; Tully, C; Tung, K L; Uchida, Y; Ulbricht, J; Valente, E; Vesztergombi, G; Vetlitskii, I; Vicinanza, D; Viertel, Gert M; Villa, S; Vivargent, M; Vlachos, S; Vodopyanov, I; Vogel, H; Vogt, H; Vorobev, I; Vorobyov, A A; Vorvolakos, A; Wadhwa, M; Wallraff, W; Wang, M; Wang, X L; Wang, Z M; Weber, A; Weber, M; Wienemann, P; Wilkens, H; Wu, S X; Wynhoff, S; Xia, L; Xu, Z Z; Yamamoto, J; Yang, B Z; Yang, C G; Yang, H J; Yang, M; Ye, J B; Yeh, S C; Zalite, A; Zalite, Yu; Zhang, Z P; Zhu, G Y; Zhu, R Y; Zichichi, A; Zilizi, G; Zimmermann, B; Zöller, M

    2000-01-01

    In a search for the Standard Model Higgs boson, carried out on 212.5~$\\mathrm{pb^{-1}}$ of data collected by the L3 detector at the highest LEP centre-of-mass energies, including 116.5~$\\mathrm{pb^{-1}}$ above $\\sqrt{s} = 206$~GeV, an excess of candidates for the process $e^+ e^- \\rightarrow Z^{*}\\rightarrow HZ$ is found for Higgs masses near 114.5~GeV. We present an analysis of our data and the characteristics of our strongest candidates.

  6. Gas cluster ion beam assisted NiPt germano-silicide formation on SiGe

    Energy Technology Data Exchange (ETDEWEB)

    Ozcan, Ahmet S., E-mail: asozcan@us.ibm.com [IBM Almaden Research Center, 650 Harry Road, San Jose, California 95120 (United States); Lavoie, Christian; Jordan-Sweet, Jean [IBM T. J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, New York 10598 (United States); Alptekin, Emre; Zhu, Frank [IBM Semiconductor Research and Development Center, 2070 Route 52, Hopewell Junction, New York 12533 (United States); Leith, Allen; Pfeifer, Brian D.; LaRose, J. D.; Russell, N. M. [TEL Epion Inc., 900 Middlesex Turnpike, Bldg. 6, Billerica, Massachusetts 01821 (United States)

    2016-04-21

    We report the formation of very uniform and smooth Ni(Pt)Si on epitaxially grown SiGe using Si gas cluster ion beam treatment after metal-rich silicide formation. The gas cluster ion implantation process was optimized to infuse Si into the metal-rich silicide layer and lowered the NiSi nucleation temperature significantly according to in situ X-ray diffraction measurements. This novel method which leads to more uniform films can also be used to control silicide depth in ultra-shallow junctions, especially for high Ge containing devices, where silicidation is problematic as it leads to much rougher interfaces.

  7. Ge growth on vicinal si(001) surfaces: island's shape and pair interaction versus miscut angle.

    Science.gov (United States)

    Persichetti, L; Sgarlata, A; Fanfoni, M; Balzarotti, A

    2011-10-01

    A complete description of Ge growth on vicinal Si(001) surfaces is provided. The distinctive mechanisms of the epitaxial growth process on vicinal surfaces are clarified from the very early stages of Ge deposition to the nucleation of 3D islands. By interpolating high-resolution scanning tunneling microscopy measurements with continuum elasticity modeling, we assess the dependence of island's shape and elastic interaction on the substrate misorientation. Our results confirm that vicinal surfaces offer an additional degree of control over the shape and symmetry of self-assembled nanostructures.

  8. Electrical characterisation of SiGe heterojunction bipolar transistors and Si pseudo-HBTS

    Science.gov (United States)

    De Barros, O.; Le Tron, B.; Woods, R. C.; Giroult-Matlakowski, G.; Vincent, G.; Brémond, G.

    1996-08-01

    This paper reports an electrical characterisation of the emitter-base junction of Si pseudo-HBTs and SiGe HBTs fabricated in a CMOS compatible single polysilicon self-aligned process. From the reverse characteristics it appears that the definition of the emitter-base junction by plasma etching induces peripheral defects that increase the base current of the transistors. Deep level transient spectroscopy measurements show a deep level in the case of SiGe base, whose spatial origin is not fully determinate up to now.

  9. GE`s worldwide experience with IFO based gypsum producing flue gas desulfurization systems

    Energy Technology Data Exchange (ETDEWEB)

    Saleem, A. [GE Environmental Systems, Lebanon, PA (United States)

    1994-12-31

    The In-Situ Forced Oxidation (IFO) process to produce gypsum in a commercial scale flue gas desulfurization (FGD) system was first demonstrated by GE Environmental Systems in 1980 at the Monticello Generating Station of Texas Utilities. Since then, the IFO technology developed and demonstrated by GE has become the industry standard and is used extensively on a world-wide basis to produce both commercial and disposable-grade gypsum. The paper gives an overview of the development, demonstration, commercial design and current status of the IFO technology.

  10. Sulphur dissociation in nuclear emulsion at 3.7 and 200A GeV

    Energy Technology Data Exchange (ETDEWEB)

    El-Nadi, M.; Abdelsalam, A.; Shaat, E.A.; Abou Moussa, Z. [Physics Department, Faculty of Science, Cairo University, Giza (Egypt); Hussien, A. [Physics Department, Faculty of Science, Cairo University, Fayoum Branch, Fayoum (Egypt); Ali-Mossa, N. [Basic Science Department, Faculty of Engineering, Banha Branch, Zagazig University, Banha (Egypt); Kamel, S.; Hafiz, M.E. [Physics Department, Faculty of Education, Ain Shams University, Cairo (Egypt); Abdel-Waged, K.H. [Physics Department, Faculty of Science, Zagazig University, Banha (Egypt)

    2002-02-01

    In this work, the electromagnetic dissociation (EMD) of sulphur projectile induced by two widely differing energies in nuclear emulsions is investigated. Although the percentages of EMD events of the total numbers of studied interactions are relatively small, i.e. 5.7 and 14.4% for 3.7 and 200A GeV interactions respectively, one could extract some results out of them. The emission of a proton through the {sup 32}S({gamma}, p){sup 31}P channel is found to be a dominant process (43.8%) at 200A GeV whereas the single alpha emission through the {sup 32}S({gamma}, {alpha}){sup 28}Si channel is the dominant one (34.0%) at 3.7A GeV. Multiplicity distributions of hydrogen and helium isotopes as well as the measured probabilities for the different modes of fragmentation are studied. The comparison of the present results, from electromagnetic and peripheral nuclear interactions, indicates the effective role of the different reaction mechanisms at ultra-relativistic energy (200A GeV). The experimental inclusive cross sections of different fragmentation modes produced in the EMD of {sup 32}S ions at 200A GeV were found to be in satisfactory agreement with the predictions of the combined approach of Pshenichnov et al. (author)

  11. Revisiting local structural changes in GeO2 glass at high pressure.

    Science.gov (United States)

    Dong, Juncai; Yao, HuRong; Guo, Zhiying; Jia, Quanjie; Wang, Yan; An, Pengfei; Gong, Yu; Liang, Yaxiang; Chen, Dongliang

    2017-09-18

    Despite the great importance in fundamental and industrial fields, understanding structural changes for pressure-induced polyamorphism in network-forming glasses remains a formidable challenge. Here, we revisited the local structural transformations in GeO2 glass up to 54 GPa using x-ray absorption fine structure (XAFS) spectroscopy via a combination diamond anvil cell and polycapillary half-lens. Three polyamorphic transitions can be clearly identified by XAFS structure refinement. First, a progressive increase of the nearest Ge-O distance and bond disorder to a maximum at ~5-16 GPa, in the same pressure region of previously observed tetrahedral-octahedral transformation. Second, a markedly decrease of the nearest Ge-O distance at ~16-22.6 GPa but a slight increase at ~22.6-32.7 GPa, with a concomitant decrease of bond disorder. This stage can be related to a second-order-like transition from less dense to dense octahedral glass. Third, another decrease in the nearest Ge-O distance at ~32.7-41.4 GPa but a slight increase up to 54 GPa, synchronized with a gradual increase of bond disorder. This stage provides strong evidence for ultrahigh-pressure polyamorphism with coordination number >6. Furthermore, cooperative modification is observed in more distant shells. Those results provide a unified local structural picture for elucidating the polyamorphic transitions and densification process in GeO2 glass. © 2017 IOP Publishing Ltd.

  12. Revisiting local structural changes in GeO2 glass at high pressure.

    Science.gov (United States)

    Dong, Juncai; Yao, Hurong; Guo, Zhiying; Jia, Quanjie; Wang, Yan; An, Pengfei; Gong, Yu; Liang, Yaxiang; Chen, Dongliang

    2017-10-20

    Despite the great importance in fundamental and industrial fields, understanding structural changes for pressure-induced polyamorphism in network-forming glasses remains a formidable challenge. Here, we revisited the local structural transformations in GeO 2 glass up to 54 GPa using x-ray absorption fine structure (XAFS) spectroscopy via a combination diamond anvil cell and polycapillary half-lens. Three polyamorphic transitions can be clearly identified by XAFS structure refinement. First, a progressive increase of the nearest Ge-O distance and bond disorder to a maximum at ~5-16 GPa, in the same pressure region of previously observed tetrahedral-octahedral transformation. Second, a marked decrease of the nearest Ge-O distance at ~16-22.6 GPa but a slight increase at ~22.6-32.7 GPa, with a concomitant decrease of bond disorder. This stage can be related to a second-order-like transition from less dense to dense octahedral glass. Third, another decrease in the nearest Ge-O distance at ~32.7-41.4 GPa but a slight increase up to 54 GPa, synchronized with a gradual increase of bond disorder. This stage provides strong evidence for ultrahigh-pressure polyamorphism with coordination number  >6. Furthermore, cooperative modification is observed in more distant shells. Those results provide a unified local structural picture for elucidating the polyamorphic transitions and densification process in GeO 2 glass.

  13. Production, characterization and operation of {sup 76}Ge enriched BEGe detectors in GERDA

    Energy Technology Data Exchange (ETDEWEB)

    Agostini, M.; Bode, T.; Budjas, D.; Janicsko Csathy, J.; Lazzaro, A.; Schoenert, S. [Technische Universitaet Muenchen, Physik Department and Excellence Cluster Universe, Munich (Germany); Allardt, M.; Barros, N.; Domula, A.; Lehnert, B.; Wester, T.; Wilsenach, H.; Zuber, K. [Technische Universitaet Dresden, Institut fuer Kern- und Teilchenphysik, Dresden (Germany); Andreotti, E. [Institute for Reference Materials and Measurements, Geel (Belgium); Eberhard Karls Universitaet Tuebingen, Physikalisches Institut, Tuebingen (Germany); Bakalyarov, A.M.; Belyaev, S.T.; Lebedev, V.I.; Zhukov, S.V. [National Research Centre ' ' Kurchatov Institute' ' , Moscow (Russian Federation); Balata, M.; D' Andrea, V.; Ioannucci, L.; Junker, M.; Laubenstein, M.; Macolino, C.; Nisi, S.; Zavarise, P. [INFN Laboratori Nazionali del Gran Sasso and Gran Sasso Science Institute, Assergi (Italy); Barabanov, I.; Bezrukov, L.; Gurentsov, V.; Inzhechik, L.V.; Kazalov, V.; Kuzminov, V.V.; Lubsandorzhiev, B.; Yanovich, E. [Institute for Nuclear Research of the Russian Academy of Sciences, Moscow (Russian Federation); Baudis, L.; Benato, G.; Walter, M. [Physik Institut der Universitaet Zuerich, Zurich (Switzerland); Bauer, C.; Heisel, M.; Heusser, G.; Hofmann, W.; Kihm, T.; Kirsch, A.; Knoepfle, K.T.; Lindner, M.; Maneschg, W.; Salathe, M.; Schreiner, J.; Schwingenheuer, B.; Simgen, H.; Smolnikov, A.; Strecker, H.; Wagner, V.; Wegmann, A. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Becerici-Schmidt, N.; Caldwell, A.; Liao, H.Y.; Majorovits, B.; O' Shaughnessy, C.; Palioselitis, D.; Schulz, O.; Vanhoefer, L. [Max-Planck-Institut fuer Physik, Munich (Germany); Bellotti, E.; Pessina, G. [Universita Milano Bicocca, Dipartimento di Fisica, Milan (Italy); INFN Milano Bicocca, Milan (Italy); Belogurov, S.; Kornoukhov, V.N. [Institute for Nuclear Research of the Russian Academy of Sciences, Moscow (Russian Federation); Institute for Theoretical and Experimental Physics, Moscow (Russian Federation); Bettini, A.; Brugnera, R.; Garfagnini, A.; Hemmer, S.; Sada, C.; Von Sturm, K. [Dipartimento di Fisica e Astronomia dell' Universita di Padova, Padua (Italy); INFN Padova, Padua (Italy); Borowicz, D. [Jagiellonian University, Institute of Physics, Cracow (Poland); Joint Institute for Nuclear Research, Dubna (Russian Federation); Brudanin, V.; Egorov, V.; Kochetov, O.; Nemchenok, I.; Rumyantseva, N.; Shevchik, E.; Zhitnikov, I.; Zinatulina, D. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Cattadori, C.; Gotti, C. [INFN Milano Bicocca, Milan (Italy); Chernogorov, A.; Demidova, E.V.; Kirpichnikov, I.V.; Vasenko, A.A. [Institute for Theoretical and Experimental Physics, Moscow (Russian Federation); Falkenstein, R.; Freund, K.; Grabmayr, P.; Hegai, A.; Jochum, J.; Schmitt, C.; Schuetz, A.K. [Eberhard Karls Universitaet Tuebingen, Physikalisches Institut, Tuebingen (Germany); Frodyma, N.; Misiaszek, M.; Pelczar, K.; Wojcik, M.; Zuzel, G. [Jagiellonian University, Institute of Physics, Cracow (Poland); Gangapshev, A. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Institute for Nuclear Research of the Russian Academy of Sciences, Moscow (Russian Federation); Gusev, K. [Joint Institute for Nuclear Research, Dubna (Russian Federation); National Research Centre ' ' Kurchatov Institute' ' , Moscow (Russian Federation); Technische Universitaet Muenchen, Physik Department and Excellence Cluster Universe, Munich (Germany); Hult, M.; Lutter, G. [Institute for Reference Materials and Measurements, Geel (Belgium); Klimenko, A.; Lubashevskiy, A. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Lippi, I.; Stanco, L.; Ur, C.A. [INFN Padova, Padua (Italy); Pandola, L. [INFN Laboratori Nazionali del Sud, Catania (Italy); Pullia, A.; Riboldi, S. [Universita degli Studi di Milano, Dipartimento di Fisica, Milan (Italy); INFN Milano (Italy); Shirchenko, M. [Joint Institute for Nuclear Research, Dubna (Russian Federation); National Research Centre ' ' Kurchatov Institute' ' , Moscow (Russian Federation); Collaboration: GERDA Collaboration

    2015-02-01

    The GERmanium Detector Array (GERDA) at the Gran Sasso Underground Laboratory (LNGS) searches for the neutrinoless double beta decay (0νββ) of {sup 76}Ge. Germanium detectors made of material with an enriched {sup 76}Ge fraction act simultaneously as sources and detectors for this decay. During Phase I of the experiment mainly refurbished semi-coaxial Ge detectors from former experiments were used. For the upcoming Phase II, 30 new {sup 76}Ge enriched detectors of broad energy germanium (BEGe)- type were produced. A subgroup of these detectors has already been deployed in GERDA during Phase I. The present paper reviews the complete production chain of these BEGe detectors including isotopic enrichment, purification, crystal growth and diode production. The efforts in optimizing the mass yield and in minimizing the exposure of the {sup 76}Ge enriched germanium to cosmic radiation during processing are described. Furthermore, characterization measurements in vacuum cryostats of the first subgroup of seven BEGe detectors and their long-term behavior in liquid argon are discussed. The detector performance fulfills the requirements needed for the physics goals of GERDA Phase II. (orig.)

  14. Production, characterization and operation of {sup 76}Ge enriched BEGe detectors in GERDA

    Energy Technology Data Exchange (ETDEWEB)

    Agostini, M. [Physik Department and Excellence Cluster Universe, Technische Universität München, Munich (Germany); Allardt, M. [Institut für Kern- und Teilchenphysik, Technische Universität Dresden, Dresden (Germany); Andreotti, E. [Institute for Reference Materials and Measurements, Geel (Belgium); Physikalisches Institut, Eberhard Karls Universität Tübingen, Tübingen (Germany); Bakalyarov, A. M. [National Research Centre “Kurchatov Institute”, Moscow (Russian Federation); Balata, M. [INFN Laboratori Nazionali del Gran Sasso and Gran Sasso Science Institute, Assergi (Italy); and others

    2015-02-03

    The GERmanium Detector Array (Gerda) at the Gran Sasso Underground Laboratory (LNGS) searches for the neutrinoless double beta decay (0νββ) of {sup 76}Ge. Germanium detectors made of material with an enriched {sup 76}Ge fraction act simultaneously as sources and detectors for this decay. During Phase I of theexperiment mainly refurbished semi-coaxial Ge detectors from former experiments were used. For the upcoming Phase II, 30 new {sup 76}Ge enriched detectors of broad energy germanium (BEGe)-type were produced. A subgroup of these detectors has already been deployed in Gerda during Phase I. The present paper reviews the complete production chain of these BEGe detectors including isotopic enrichment, purification, crystal growth and diode production. The efforts in optimizing the mass yield and in minimizing the exposure of the {sup 76}Ge enriched germanium to cosmic radiation during processing are described. Furthermore, characterization measurements in vacuum cryostats of the first subgroup of seven BEGe detectors and their long-term behavior in liquid argon are discussed. The detector performance fulfills the requirements needed for the physics goals of Gerda Phase II.

  15. The 76Ge Program to Search for Neutrinoless Double-Beta Decay

    Science.gov (United States)

    Guiseppe, Vincente

    2017-09-01

    Neutrinoless double-beta decay searches play a major role in determining the nature of neutrinos, the existence of a lepton violating process, and the effective Majorana neutrino mass. The Majorana and Gerda Collaborations are operating arrays of high purity Ge detectors to search for neutrinoless double-beta decay in 76Ge. The Majorana Demonstrator is operating at the Sanford Underground Research Facility in South Dakota while the Gerda experiment is operating at LNGS in Italy. The Gerda and Majorana Demonstrator experiments have achieved the lowest backgrounds in the neutrinoless double-beta decay region of interest. These results, coupled with the superior energy resolution (0.1%) of Ge detectors demonstrate that 76Ge is an ideal isotope for a large next generation experiment. The LEGEND collaboration, with 220 members from 47 institutions around the world, has been formed to pursue a ton scale 76Ge experiment. Building on the successes of Gerda and Majorana, the LEGEND collaboration aims to develop a phased neutrinoless double-beta decay experimental program with discovery potential at a half-life significantly longer than 1027 years. This talk will present the initial results from the Majorana Demonstrator and Gerda experiments and the plan for the LEGEND program.

  16. Production, characterization and operation of Ge enriched BEGe detectors in GERDA

    Science.gov (United States)

    Agostini, M.; Allardt, M.; Andreotti, E.; Bakalyarov, A. M.; Balata, M.; Barabanov, I.; Barros, N.; Baudis, L.; Bauer, C.; Becerici-Schmidt, N.; Bellotti, E.; Belogurov, S.; Belyaev, S. T.; Benato, G.; Bettini, A.; Bezrukov, L.; Bode, T.; Borowicz, D.; Brudanin, V.; Brugnera, R.; Budjáš, D.; Caldwell, A.; Cattadori, C.; Chernogorov, A.; D'Andrea, V.; Demidova, E. V.; Domula, A.; Egorov, V.; Falkenstein, R.; Freund, K.; Frodyma, N.; Gangapshev, A.; Garfagnini, A.; Gotti, C.; Grabmayr, P.; Gurentsov, V.; Gusev, K.; Hegai, A.; Heisel, M.; Hemmer, S.; Heusser, G.; Hofmann, W.; Hult, M.; Inzhechik, L. V.; Ioannucci, L.; Janicskó Csáthy, J.; Jochum, J.; Junker, M.; Kazalov, V.; Kihm, T.; Kirpichnikov, I. V.; Kirsch, A.; Klimenko, A.; Knöpfle, K. T.; Kochetov, O.; Kornoukhov, V. N.; Kuzminov, V. V.; Laubenstein, M.; Lazzaro, A.; Lebedev, V. I.; Lehnert, B.; Liao, H. Y.; Lindner, M.; Lippi, I.; Lubashevskiy, A.; Lubsandorzhiev, B.; Lutter, G.; Macolino, C.; Majorovits, B.; Maneschg, W.; Misiaszek, M.; Nemchenok, I.; Nisi, S.; O'Shaughnessy, C.; Palioselitis, D.; Pandola, L.; Pelczar, K.; Pessina, G.; Pullia, A.; Riboldi, S.; Rumyantseva, N.; Sada, C.; Salathe, M.; Schmitt, C.; Schreiner, J.; Schulz, O.; Schütz, A.-K.; Schwingenheuer, B.; Schönert, S.; Shevchik, E.; Shirchenko, M.; Simgen, H.; Smolnikov, A.; Stanco, L.; Strecker, H.; Ur, C. A.; Vanhoefer, L.; Vasenko, A. A.; von Sturm, K.; Wagner, V.; Walter, M.; Wegmann, A.; Wester, T.; Wilsenach, H.; Wojcik, M.; Yanovich, E.; Zavarise, P.; Zhitnikov, I.; Zhukov, S. V.; Zinatulina, D.; Zuber, K.; Zuzel, G.

    2015-02-01

    The GERmanium Detector Array ( Gerda) at the Gran Sasso Underground Laboratory (LNGS) searches for the neutrinoless double beta decay () of Ge. Germanium detectors made of material with an enriched Ge fraction act simultaneously as sources and detectors for this decay. During Phase I of theexperiment mainly refurbished semi-coaxial Ge detectors from former experiments were used. For the upcoming Phase II, 30 new Ge enriched detectors of broad energy germanium (BEGe)-type were produced. A subgroup of these detectors has already been deployed in Gerda during Phase I. The present paper reviews the complete production chain of these BEGe detectors including isotopic enrichment, purification, crystal growth and diode production. The efforts in optimizing the mass yield and in minimizing the exposure of the Ge enriched germanium to cosmic radiation during processing are described. Furthermore, characterization measurements in vacuum cryostats of the first subgroup of seven BEGe detectors and their long-term behavior in liquid argon are discussed. The detector performance fulfills the requirements needed for the physics goals of Gerda Phase II.

  17. Magnetic characteristics and nanostructures of FePt granular films with GeO2 segregant

    Science.gov (United States)

    Ono, Takuya; Moriya, Tomohiro; Hatayama, Masatoshi; Tsumura, Kaoru; Kikuchi, Nobuaki; Okamoto, Satoshi; Kitakami, Osamu; Shimatsu, Takehito

    2017-01-01

    To realize a granular film composed of L10-FePt grains with high uniaxial magnetic anisotropy energy, Ku, and segregants for energy-assisted magnetic recording, a FePt-GeO2/FePt-C stacked film was investigated in the engineering process. The FePt-GeO2/FePt-C stacked film fabricated at a substrate temperature of 450 °C realized uniaxial magnetic anisotropy, Kugrain , of about 2.5 × 107 erg/cm3, which is normalized by the volume fraction of FePt grains, and a granular structure with an averaged grain size of 7.7 nm. As the thickness of the FePt-GeO2 upper layer was increased to 9 nm, the Ku values were almost constant. That result differs absolutely from the thickness dependences of the other oxide segregant materials such as SiO2 and TiO2. Such differences on the oxide segregant are attributed to their chemical bond. The strong covalent bond of GeO2 is expected to result in high Ku of the FePt-GeO2/FePt-C stacked films.

  18. Misfit-guided self-organization of anticorrelated Ge quantum dot arrays on Si nanowires.

    Science.gov (United States)

    Kwon, Soonshin; Chen, Zack C Y; Kim, Ji-Hun; Xiang, Jie

    2012-09-12

    Misfit-strain guided growth of periodic quantum dot (QD) arrays in planar thin film epitaxy has been a popular nanostructure fabrication method. Engineering misfit-guided QD growth on a nanoscale substrate such as the small curvature surface of a nanowire represents a new approach to self-organized nanostructure preparation. Perhaps more profoundly, the periodic stress underlying each QD and the resulting modulation of electro-optical properties inside the nanowire backbone promise to provide a new platform for novel mechano-electronic, thermoelectronic, and optoelectronic devices. Herein, we report a first experimental demonstration of self-organized and self-limited growth of coherent, periodic Ge QDs on a one-dimensional Si nanowire substrate. Systematic characterizations reveal several distinctively different modes of Ge QD ordering on the Si nanowire substrate depending on the core diameter. In particular, Ge QD arrays on Si nanowires of around 20 nm diameter predominantly exhibit an anticorrelated pattern whose wavelength agrees with theoretical predictions. The correlated pattern can be attributed to propagation and correlation of misfit strain across the diameter of the thin nanowire substrate. The QD array growth is self-limited as the wavelength of the QDs remains unchanged even after prolonged Ge deposition. Furthermore, we demonstrate a direct kinetic transformation from a uniform Ge shell layer to discrete QD arrays by a postgrowth annealing process.

  19. Search for a massive diphoton resonance at $\\sqrt{s}$ = 91-172 GeV

    CERN Document Server

    Ackerstaff, K; Allison, J; Altekamp, N; Anderson, K J; Anderson, S; Arcelli, S; Asai, S; Axen, D A; Azuelos, Georges; Ball, A H; Barberio, E; Barlow, R J; Bartoldus, R; Batley, J Richard; Baumann, S; Bechtluft, J; Beeston, C; Behnke, T; Bell, A N; Bell, K W; Bella, G; Bentvelsen, Stanislaus Cornelius Maria; Bethke, Siegfried; Biebel, O; Biguzzi, A; Bird, S D; Blobel, Volker; Bloodworth, Ian J; Bloomer, J E; Bobinski, M; Bock, P; Bonacorsi, D; Boutemeur, M; Bouwens, B T; Braibant, S; Brigliadori, L; Brown, R M; Burckhart, Helfried J; Burgard, C; Bürgin, R; Capiluppi, P; Carnegie, R K; Carter, A A; Carter, J R; Chang, C Y; Charlton, D G; Chrisman, D; Clarke, P E L; Cohen, I; Conboy, J E; Cooke, O C; Cuffiani, M; Dado, S; Dallapiccola, C; Dallavalle, G M; Davis, R; De Jong, S; del Pozo, L A; Desch, Klaus; Dienes, B; Dixit, M S; do Couto e Silva, E; Doucet, M; Duchovni, E; Duckeck, G; Duerdoth, I P; Eatough, D; Edwards, J E G; Estabrooks, P G; Evans, H G; Evans, M; Fabbri, Franco Luigi; Fanti, M; Faust, A A; Fiedler, F; Fierro, M; Fischer, H M; Fleck, I; Folman, R; Fong, D G; Foucher, M; Fürtjes, A; Futyan, D I; Gagnon, P; Gary, J W; Gascon, J; Gascon-Shotkin, S M; Geddes, N I; Geich-Gimbel, C; Geralis, T; Giacomelli, G; Giacomelli, P; Giacomelli, R; Gibson, V; Gibson, W R; Gingrich, D M; Glenzinski, D A; Goldberg, J; Goodrick, M J; Gorn, W; Grandi, C; Gross, E; Grunhaus, Jacob; Gruwé, M; Hajdu, C; Hanson, G G; Hansroul, M; Hapke, M; Hargrove, C K; Hart, P A; Hartmann, C; Hauschild, M; Hawkes, C M; Hawkings, R; Hemingway, Richard J; Herndon, M; Herten, G; Heuer, R D; Hildreth, M D; Hill, J C; Hillier, S J; Hobson, P R; Homer, R James; Honma, A K; Horváth, D; Hossain, K R; Howard, R; Hüntemeyer, P; Hutchcroft, D E; Igo-Kemenes, P; Imrie, D C; Ingram, M R; Ishii, K; Jawahery, A; Jeffreys, P W; Jeremie, H; Jimack, Martin Paul; Joly, A; Jones, C R; Jones, G; Jones, M; Jost, U; Jovanovic, P; Junk, T R; Karlen, D A; Kartvelishvili, V G; Kawagoe, K; Kawamoto, T; Kayal, P I; Keeler, Richard K; Kellogg, R G; Kennedy, B W; Kirk, J; Klier, A; Kluth, S; Kobayashi, T; Kobel, M; Koetke, D S; Kokott, T P; Kolrep, M; Komamiya, S; Kress, T; Krieger, P; Von Krogh, J; Kyberd, P; Lafferty, G D; Lahmann, R; Lai, W P; Lanske, D; Lauber, J; Lautenschlager, S R; Layter, J G; Lazic, D; Lee, A M; Lefebvre, E; Lellouch, Daniel; Letts, J; Levinson, L; Lloyd, S L; Loebinger, F K; Long, G D; Losty, Michael J; Ludwig, J; Macchiolo, A; MacPherson, A L; Mannelli, M; Marcellini, S; Markus, C; Martin, A J; Martin, J P; Martínez, G; Mashimo, T; Mättig, P; McDonald, W J; McKenna, J A; McKigney, E A; McMahon, T J; McPherson, R A; Meijers, F; Menke, S; Merritt, F S; Mes, H; Meyer, J; Michelini, Aldo; Mikenberg, G; Miller, D J; Mincer, A; Mir, R; Mohr, W; Montanari, A; Mori, T; Morii, M; Müller, U; Mihara, S; Nagai, K; Nakamura, I; Neal, H A; Nellen, B; Nisius, R; O'Neale, S W; Oakham, F G; Odorici, F; Ögren, H O; Oh, A; Oldershaw, N J; Oreglia, M J; Orito, S; Pálinkás, J; Pásztor, G; Pater, J R; Patrick, G N; Patt, J; Pearce, M J; Pérez-Ochoa, R; Petzold, S; Pfeifenschneider, P; Pilcher, J E; Pinfold, J L; Plane, D E; Poffenberger, P R; Poli, B; Posthaus, A; Rees, D L; Rigby, D; Robertson, S; Robins, S A; Rodning, N L; Roney, J M; Rooke, A M; Ros, E; Rossi, A M; Routenburg, P; Rozen, Y; Runge, K; Runólfsson, O; Ruppel, U; Rust, D R; Rylko, R; Sachs, K; Saeki, T; Sarkisyan-Grinbaum, E; Sbarra, C; Schaile, A D; Schaile, O; Scharf, F; Scharff-Hansen, P; Schenk, P; Schieck, J; Schleper, P; Schmitt, B; Schmitt, S; Schöning, A; Schröder, M; Schultz-Coulon, H C; Schumacher, M; Schwick, C; Scott, W G; Shears, T G; Shen, B C; Shepherd-Themistocleous, C H; Sherwood, P; Siroli, G P; Sittler, A; Skillman, A; Skuja, A; Smith, A M; Snow, G A; Sobie, Randall J; Söldner-Rembold, S; Springer, R W; Sproston, M; Stephens, K; Steuerer, J; Stockhausen, B; Stoll, K; Strom, D; Szymanski, P; Tafirout, R; Talbot, S D; Tanaka, S; Taras, P; Tarem, S; Teuscher, R; Thiergen, M; Thomson, M A; Von Törne, E; Towers, S; Trigger, I; Trócsányi, Z L; Tsur, E; Turcot, A S; Turner-Watson, M F; Utzat, P; Van Kooten, R; Verzocchi, M; Vikas, P; Vokurka, E H; Voss, H; Wäckerle, F; Wagner, A; Ward, C P; Ward, D R; Watkins, P M; Watson, A T; Watson, N K; Wells, P S; Wermes, N; White, J S; Wilkens, B; Wilson, G W; Wilson, J A; Wolf, G; Wyatt, T R; Yamashita, S; Yekutieli, G; Zacek, V; Zer-Zion, D

    1998-01-01

    A search for the resonant production of high mass photon pairs associated with a leptonic or hadronic system has been performed using a total data sample of 25.7 pb^-1 taken at centre-of-mass energies between 130 GeV and 172 GeV with the OPAL detector at LEP. The observed number of events is consistent with the expected number from Standard Model processes. The observed candidates are combined with search results from sqrt{s} ~ M_Z to place limits on Br(H^0 -> gamma gamma) within the Standard Model for Higgs boson masses up to 77 GeV, and on the production cross section of any scalar resonance decaying into di-photons. Upper limits on Br(H^0 -> gamma gamma) x sigma(e^+e^- -> H^0 Z^0) of 290 - 830 fb are obtained over 40 < M_H < 160 GeV. Type-I two-Higgs-doublet scalars which couple only to gauge bosons are ruled out up to a mass of 76.5 GeV at the 95% confidence level.

  20. Origin, secret, and application of the ideal phase-change material GeSbTe

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, Noboru [Advanced Technology Research Laboratories, Panasonic Corporation, 3-4 Hikaridai, Seika-cho, Soraku-gun, 619-0237 Kyoto (Japan); Nanoelectronics Research Institute, National Institute of Advanced Industrial Science and Technology, Central 4, 1-1-1, Higashi, Tsukuba, Ibaraki 305-8562 (Japan)

    2012-10-15

    Discovery of the GeSbTe phase-change alloy in particular along the GeTe-Sb{sub 2}Te{sub 3} tie-line took place in the mid-1980s. The amorphous alloys showed ideal properties, for example, high thermal stability at r.t. and laser-induced rapid crystallization with large optical changes. Thereafter, GeSbTe was successively applied to various optical disks such as DVDs and BDs. Through DSC and XRD analyses, the appearance of the metastable phase having a NaCl-type structure was observed over a wide compositional region. This was the ''key'' to realizing the ideal phase-change properties. During this year, the role of the constituent elements of Ge and Sb became clear by RMC modeling using AXS data at SPring-8, where the ''nucleation dominant crystallization process'' was well explained. The aspect of the latest Blu-ray Disc (BD) product of Panasonic: GeSbTe phase-change films are utilized in every recording layer. It is seen that the front-side recording layers, L1 and L2, are highly transparent. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  1. High-pressure EXAFS study of vitreous GeO2 up to 44 GPa

    International Nuclear Information System (INIS)

    Baldini, M.; Aquilanti, G.; Mao, H-k.; Yang, W.; Shen, G.; Pascarelli, S.; Mao, W. L.

    2010-01-01

    High-pressure extended x-ray absorption fine-structure measurements were performed on amorphous GeO 2 over increasing and decreasing pressure cycles at pressures up to 44 GPa. Several structural models based on crystalline phases with fourfold, fivefold, and sixfold coordination were used to fit the Ge-O first shell. The Ge-O bond lengths gradually increased up to 30 GPa. Three different pressure regimes were identified in the pressure evolution of the Ge-O bond distances. Below 13 GPa, the local structure was well described by a fourfold 'quartzlike' model whereas a disordered region formed by a mixture of four- and five-coordinated germanium-centered polyhedra was observed in the intermediate pressure range between 13 and 30 GPa. Above 30 GPa the structural transition to the maximum coordination could be considered complete. The present results shed light on the GeO 2 densification process and on the nature of the amorphous-amorphous transition, suggesting that the transition is more gradual and continuous than what has been previously reported.

  2. Ge{sup 4+} doped TiO{sub 2} for stoichiometric degradation of warfare agents

    Energy Technology Data Exchange (ETDEWEB)

    Stengl, Vaclav, E-mail: stengl@iic.cas.cz [Department of Solid State Chemistry, Institute of Inorganic Chemistry AS CR v.v.i., 250 68 Rez (Czech Republic); Grygar, Tomas Matys [Department of Solid State Chemistry, Institute of Inorganic Chemistry AS CR v.v.i., 250 68 Rez (Czech Republic); Oplustil, Frantisek; Nemec, Tomas [Military Technical Institute of Protection Brno, Veslarska 230, 628 00 Brno (Czech Republic)

    2012-08-15

    Highlights: Black-Right-Pointing-Pointer We prepared nanodisperse Ge{sup 4+} doped titania by a novel synthesis method. Black-Right-Pointing-Pointer Synthesis does not involve organic solvents, organometallics nor thermal processes. Black-Right-Pointing-Pointer The prepared materials are efficient in removal of chemical warfare agents. Black-Right-Pointing-Pointer Ge{sup 4+} doping improves rate of removal of soman and agent VX by TiO{sub 2}. - Abstract: Germanium doped TiO{sub 2} was prepared by homogeneous hydrolysis of aqueous solutions of GeCl{sub 4} and TiOSO{sub 4} with urea. The synthesized samples were characterized by X-ray diffraction, scanning electron microscopy, EDS analysis, specific surface area (BET) and porosity determination (BJH). Ge{sup 4+} doping increases surface area and content of amorphous phase in prepared samples. These oxides were used in an experimental evaluation of their reactivity with chemical warfare agent, sulphur mustard, soman and agent VX. Ge{sup 4+} doping worsens sulphur mustard degradation and improves soman and agent VX degradation. The best degree of removal (degradation), 100% of soman, 99% of agent VX and 95% of sulphur mustard, is achieved with sample with 2 wt.% of germanium.

  3. Gold fillings unravel the vacancy role in the phase transition of GeTe

    Science.gov (United States)

    Feng, Jinlong; Xu, Meng; Wang, Xiaojie; Lin, Qi; Cheng, Xiaomin; Xu, Ming; Tong, Hao; Miao, Xiangshui

    2018-02-01

    Phase change memory (PCM) is an important candidate for future memory devices. The crystalline phase of PCM materials contains abundant intrinsic vacancies, which plays an important role in the rapid phase transition upon memory switching. However, few experimental efforts have been invested to study these invisible entities. In this work, Au dopants are alloyed into the crystalline GeTe to fill the intrinsic Ge vacancies so that the role of these vacancies in the amorphization of GeTe can be indirectly studied. As a result, the reduction of Ge vacancies induced by Au dopants hampers the amorphization of GeTe as the activation energy of this process becomes higher. This is because the vacancy-interrupted lattice can be "repaired" by Au dopants with the recovery of bond connectivity. Our results demonstrate the importance of vacancies in the phase transition of chalcogenides, and we employ the percolation theory to explain the impact of these intrinsic defects on this vacancy-ridden crystal quantitatively. Specifically, the threshold of amorphization increases with the decrease in vacancies. The understanding of the vacancy effect sheds light on the long-standing puzzle of the mechanism of ultra-fast phase transition in PCMs. It also paves the way for designing low-power-consumption electronic devices by reducing the threshold of amorphization in chalcogenides.

  4. Si0.85Ge0.15 oxynitridation in nitric oxide/nitrous oxide ambient

    International Nuclear Information System (INIS)

    Dasgupta, Anindya; Takoudis, Christos G.; Lei Yuanyuan; Browning, Nigel D.

    2003-01-01

    Low temperature, nitric oxide (NO)/nitrous oxide (N 2 O) aided, sub-35 Aa Si 0.85 Ge 0.15 oxynitrides have been grown at 550 and 650 deg. C, while the oxynitridation feed gases have been preheated to 900 and 1000 deg. C, respectively, before entering the reaction zone. X-ray photoelectron spectroscopy and secondary ion mass spectroscopy (SIMS) data suggest that NO-assisted oxynitridation incorporates more nitrogen than the N 2 O-assisted one, while there is minimal Ge segregation towards the dielectric/substrate interface in both oxynitridation processes. Moreover, SIMS results suggest that nitrogen is distributed throughout the film in contrast to high temperature Si oxynitridation, where nitrogen incorporation takes place near the dielectric/substrate interface. Z-contrast imaging with scanning transmission electron microscopy shows that the oxynitride grown in NO at 650 degree sign C has a sharp interface with the bulk Si 0.85 Ge 0.15 , while the roughness of the dielectric/Si 0.85 Ge 0.15 substrate interface is less than 2 Aa. These results are discussed in the context of an overall mechanism of SiGe oxynitridation

  5. Solute trapping of Ge in Al

    International Nuclear Information System (INIS)

    Smith, P.M.; West, J.A.; Aziz, M.J.

    1992-01-01

    This paper reports on partitioning during rapid solidification of dilute Al-Ge alloys. Implanted thin films of Al have been pulsed-laser melted to obtain solidification at velocities in the range of 0.01 ms to 3.3 m/s, as measured by the transient conductance technique. Previous and subsequent Rutherford Backscattering depth profiling of the Ge solute in the Al alloys has been used to determine the nonequilibrium partition coefficient k. A significant degree of lateral film growth during solidification confines determination of k to the placing of an upper bound of 0.22 on k for solidification velocities in this range. The authors place a lower limit of 10 m/s on the diffusive velocity, which locates the transition from solute partitioning to solute trapping in the Continuous Growth Model

  6. The 400 GeV proton synchrotron

    International Nuclear Information System (INIS)

    1976-05-01

    A general account is given of the 400-GeV proton synchrotron, known as Super Proton Synchrotron (SPS), of the European Organization for Nuclear Research (CERN) at Geneva. A brief chapter on the history of the project covers the steps leading to the earlier plan for a 300-GeV accelerator at a new CERN laboratory elsewhere in Europe, abandoned in 1971 in favour of the present machine, and the progress of construction of the latter. The general features of the SPS design are outlined, illustrated by an aerial view of the CERN site, a plan of the SPS, and interior views of the SPS ring tunnel and main control room. (WSN)

  7. An X-band Schottky diode mixer in SiGe technology with tunable Marchand balun

    DEFF Research Database (Denmark)

    Michaelsen, Rasmus Schandorph; Johansen, Tom Keinicke; Tamborg, Kjeld M.

    2017-01-01

    In this paper, we propose a double balanced mixer with a tunable Marchand balun. The circuit is designed in a SiGe BiCMOS process using Schottky diodes. The tunability of the Marchand balun is used to enhance critical parameters for double balanced mixers. The local oscillator-IF isolation can...

  8. Europe at 400 GeV

    International Nuclear Information System (INIS)

    Walgate, R.

    1977-01-01

    The inaugural opening of the 400 GeV proton accelerator at CERN took place on 7 May 1977. A review of difficulties encountered during the 14 years since the SPS was first proposed is given and experiments already underway are outlined. The advantages of this facility over Fermilab and the type of experiment which can now be undertaken to answer some of the questions left open by Fermilab are discussed. (U.K.)

  9. GRETEL, Ge(Li) Gamma Spectra Unfolding

    International Nuclear Information System (INIS)

    1975-01-01

    1 - Nature of physical problem solved: The program performs the quantitative analysis of gamma-ray spectra obtained by Ge(Li) detectors, using special libraries which are prepared for each particular problem. 2 - Method of solution: The computer routines which detect and evaluate peak areas perform the following operations: - local smoothing of the spectrum; - first derivative of the smoothed spectrum, - peak location according to the change of sign of the first derivative; - computation of the net area of each peak found

  10. Morphological analysis of GeTe in inline phase change switches

    Energy Technology Data Exchange (ETDEWEB)

    King, Matthew R., E-mail: matthew.king2@ngc.com [Northrop Grumman Electronic Systems, Advanced Concepts and Technologies Division, 1212 Winterson Rd., Linthicum, Maryland 21090 (United States); Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States); El-Hinnawy, Nabil [Northrop Grumman Electronic Systems, Advanced Concepts and Technologies Division, 1212 Winterson Rd., Linthicum, Maryland 21090 (United States); Department of Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States); Salmon, Mike; Gu, Jitty [Evans Analytical Group, 628 Hutton St., Raleigh, North Carolina 27606 (United States); Wagner, Brian P.; Jones, Evan B.; Howell, Robert S.; Nichols, Doyle T.; Young, Robert M. [Northrop Grumman Electronic Systems, Advanced Concepts and Technologies Division, 1212 Winterson Rd., Linthicum, Maryland 21090 (United States); Borodulin, Pavel [Northrop Grumman Electronic Systems, Advanced Concepts and Technologies Division, 1212 Winterson Rd., Linthicum, Maryland 21090 (United States); Department of Electrical and Computer Engineering, The Johns Hopkins University, Baltimore, Maryland 21218 (United States)

    2015-09-07

    Crystallization and amorphization phenomena in indirectly heated phase change material-based devices were investigated. Scanning transmission electron microscopy was utilized to explore GeTe phase transition processes in the context of the unique inline phase change switch (IPCS) architecture. A monolithically integrated thin film heating element successfully converted GeTe to ON and OFF states. Device cycling prompted the formation of an active area which sustains the majority of structural changes during pulsing. A transition region on both sides of the active area consisting of polycrystalline GeTe and small nuclei (<15 nm) in an amorphous matrix was also observed. The switching mechanism, determined by variations in pulsing parameters, was shown to be predominantly growth-driven. A preliminary model for crystallization and amorphization in IPCS devices is presented.

  11. Self-Ordered Voids Formation in SiO2 Matrix by Ge Outdiffusion

    Directory of Open Access Journals (Sweden)

    B. Pivac

    2018-01-01

    Full Text Available The annealing behavior of very thin SiO2/Ge multilayers deposited on Si substrate by e-gun deposition in high vacuum was explored. It is shown that, after annealing at moderate temperatures (800°C in inert atmosphere, Ge is completely outdiffused from the SiO2 matrix leaving small (about 3 nm spherical voids embedded in the SiO2 matrix. These voids are very well correlated and formed at distances governed by the preexisting multilayer structure (in vertical direction and self-organization (in horizontal direction. The formed films produce intensive photoluminescence (PL with a peak at 500 nm. The explored dynamics of the PL decay show the existence of a very rapid process similar to the one found at Ge/SiO2 defected interface layers.

  12. Hard-photon production at $\\sqrt{s}$ = 161 and 172 GeV at LEP

    CERN Document Server

    Acciarri, M; Aguilar-Benítez, M; Ahlen, S P; Alcaraz, J; Alemanni, G; Allaby, James V; Aloisio, A; Alverson, G; Alviggi, M G; Ambrosi, G; Anderhub, H; Andreev, V P; Angelescu, T; Anselmo, F; Arefev, A; Azemoon, T; Aziz, T; Bagnaia, P; Baksay, L; Banerjee, S; Banerjee, Sw; Banicz, K; Barczyk, A; Barillère, R; Barone, L; Bartalini, P; Baschirotto, A; Basile, M; Battiston, R; Bay, A; Becattini, F; Becker, U; Behner, F; Berdugo, J; Berges, P; Bertucci, B; Betev, B L; Bhattacharya, S; Biasini, M; Biland, A; Bilei, G M; Blaising, J J; Blyth, S C; Bobbink, Gerjan J; Böck, R K; Böhm, A; Boldizsar, L; Borgia, B; Bourilkov, D; Bourquin, Maurice; Braccini, S; Branson, J G; Brigljevic, V; Brock, I C; Buffini, A; Buijs, A; Burger, J D; Burger, W J; Busenitz, J K; Button, A M; Cai, X D; Campanelli, M; Capell, M; Cara Romeo, G; Carlino, G; Cartacci, A M; Casaus, J; Castellini, G; Cavallari, F; Cavallo, N; Cecchi, C; Cerrada-Canales, M; Cesaroni, F; Chamizo-Llatas, M; Chang, Y H; Chaturvedi, U K; Chekanov, S V; Chemarin, M; Chen, A; Chen, G; Chen, G M; Chen, H F; Chen, H S; Chéreau, X J; Chiefari, G; Chien, C Y; Cifarelli, Luisa; Cindolo, F; Civinini, C; Clare, I; Clare, R; Cohn, H O; Coignet, G; Colijn, A P; Colino, N; Commichau, V; Costantini, S; Cotorobai, F; de la Cruz, B; Csilling, Akos; Dai, T S; D'Alessandro, R; De Asmundis, R; Degré, A; Deiters, K; Della Volpe, D; Denes, P; De Notaristefani, F; DiBitonto, Daryl; Diemoz, M; Van Dierendonck, D N; Di Lodovico, F; Dionisi, C; Dittmar, Michael; Dominguez, A; Doria, A; Dova, M T; Duchesneau, D; Duinker, P; Durán, I; Dutta, S; Easo, S; Efremenko, Yu V; El-Mamouni, H; Engler, A; Eppling, F J; Erné, F C; Ernenwein, J P; Extermann, Pierre; Fabre, M; Faccini, R; Falciano, S; Favara, A; Fay, J; Fedin, O; Felcini, Marta; Fenyi, B; Ferguson, T; Ferroni, F; Fesefeldt, H S; Fiandrini, E; Field, J H; Filthaut, Frank; Fisher, P H; Fisk, I; Forconi, G; Fredj, L; Freudenreich, Klaus; Furetta, C; Galaktionov, Yu; Ganguli, S N; García-Abia, P; Gau, S S; Gentile, S; Gheordanescu, N; Giagu, S; Goldfarb, S; Goldstein, J; Gong, Z F; Gougas, Andreas; Gratta, Giorgio; Grünewald, M W; Gupta, V K; Gurtu, A; Gutay, L J; Hartmann, B; Hasan, A; Hatzifotiadou, D; Hebbeker, T; Hervé, A; Van Hoek, W C; Hofer, H; Hong, S J; Hoorani, H; Hou, S R; Hu, G; Innocente, Vincenzo; Jenkes, K; Jin, B N; Jones, L W; de Jong, P; Josa-Mutuberria, I; Kasser, A; Khan, R A; Kamrad, D; Kamyshkov, Yu A; Kapustinsky, J S; Karyotakis, Yu; Kaur, M; Kienzle-Focacci, M N; Kim, D; Kim, D H; Kim, J K; Kim, S C; Kim, Y G; Kinnison, W W; Kirkby, A; Kirkby, D; Kirkby, Jasper; Kiss, D; Kittel, E W; Klimentov, A; König, A C; Kopp, A; Korolko, I; Koutsenko, V F; Krämer, R W; Krenz, W; Kunin, A; Ladrón de Guevara, P; Laktineh, I; Landi, G; Lapoint, C; Lassila-Perini, K M; Laurikainen, P; Lebeau, M; Lebedev, A; Lebrun, P; Lecomte, P; Lecoq, P; Le Coultre, P; Le Goff, J M; Leiste, R; Leonardi, E; Levchenko, P M; Li Chuan; Lin, C H; Lin, W T; Linde, Frank L; Lista, L; Liu, Z A; Lohmann, W; Longo, E; Lu, W; Lü, Y S; Lübelsmeyer, K; Luci, C; Luckey, D; Luminari, L; Lustermann, W; Ma Wen Gan; Maity, M; Majumder, G; Malgeri, L; Malinin, A; Maña, C; Mangeol, D J J; Mangla, S; Marchesini, P A; Marin, A; Martin, J P; Marzano, F; Massaro, G G G; McNally, D; McNeil, R R; Mele, S; Merola, L; Meschini, M; Metzger, W J; Von der Mey, M; Mi, Y; Mihul, A; Van Mil, A J W; Mirabelli, G; Mnich, J; Molnár, P; Monteleoni, B; Moore, R; Morganti, S; Moulik, T; Mount, R; Müller, S; Muheim, F; Muijs, A J M; Nahn, S; Napolitano, M; Nessi-Tedaldi, F; Newman, H; Niessen, T; Nippe, A; Nisati, A; Nowak, H; Oh, Yu D; Opitz, H; Organtini, G; Ostonen, R; Palomares, C; Pandoulas, D; Paoletti, S; Paolucci, P; Park, H K; Park, I H; Pascale, G; Passaleva, G; Patricelli, S; Paul, T; Pauluzzi, M; Paus, C; Pauss, Felicitas; Peach, D; Pei, Y J; Pensotti, S; Perret-Gallix, D; Petersen, B; Petrak, S; Pevsner, A; Piccolo, D; Pieri, M; Pinto, J C; Piroué, P A; Pistolesi, E; Plyaskin, V; Pohl, M; Pozhidaev, V; Postema, H; Produit, N; Prokofev, D; Prokofiev, D O; Rahal-Callot, G; Raja, N; Rancoita, P G; Rattaggi, M; Raven, G; Razis, P A; Read, K; Ren, D; Rescigno, M; Reucroft, S; Van Rhee, T; Riemann, S; Riles, K; Robohm, A; Rodin, J; Roe, B P; Romero, L; Rosier-Lees, S; Rosselet, P; Van Rossum, W; Roth, S; Rubio, Juan Antonio; Ruschmeier, D; Rykaczewski, H; Salicio, J; Sánchez, E; Sanders, M P; Sarakinos, M E; Sarkar, S; Sassowsky, M; Schäfer, C; Shchegelskii, V; Schmidt-Kärst, S; Schmitz, D; Schmitz, P; Scholz, N; Schopper, Herwig Franz; Schotanus, D J; Schwenke, J; Schwering, G; Sciacca, C; Sciarrino, D; Servoli, L; Shevchenko, S; Shivarov, N; Shoutko, V; Shukla, J; Shumilov, E; Shvorob, A V; Siedenburg, T; Son, D; Sopczak, André; Smith, B; Spillantini, P; Steuer, M; Stickland, D P; Stone, A; Stone, H; Stoyanov, B; Strässner, A; Strauch, K; Sudhakar, K; Sultanov, G G; Sun, L Z; Susinno, G F; Suter, H; Swain, J D; Tang, X W; Tauscher, Ludwig; Taylor, L; Ting, Samuel C C; Ting, S M; Tonutti, M; Tonwar, S C; Tóth, J; Tully, C; Tuchscherer, H; Tung, K L; Uchida, Y; Ulbricht, J; Uwer, U; Valente, E; Van de Walle, R T; Vesztergombi, G; Vetlitskii, I; Viertel, Gert M; Vivargent, M; Völkert, R; Vogel, H; Vogt, H; Vorobev, I; Vorobyov, A A; Vorvolakos, A; Wadhwa, M; Wallraff, W; Wang, J C; Wang, X L; Wang, Z M; Weber, A; Wittgenstein, F; Wu, S X; Wynhoff, S; Xu, J; Xu, Z Z; Yang, B Z; Yang, C G; Yao, X Y; Ye, J B; Yeh, S C; You, J M; Zalite, A; Zalite, Yu; Zemp, P; Zeng, Y; Zhang, Z; Zhang, Z P; Zhou, B; Zhu, G Y; Zhu, R Y; Zichichi, Antonino; Ziegler, F

    1997-01-01

    We have studied the process $e^+e^-{\\rightarrow}\\rm n {\\gamma}$ $(\\rm n{\\ge}2)$ at centre-of-mass energies of 161.3 GeV and 172.1 GeV. The analysis is based on a sample of events collected by the L3 detector in 1996 corresponding to total integrated luminosities of 10.7 ${\\rm pb^{-1}}$ and 10.1 ${\\rm pb^{-1}}$ respectively. The observed rates of events with two and more photons and the characteristic distributions are in good agreement with the Standard Model expectations. This is used to set lower limits on contact interaction energy scale parameters, on the QED cut-off parameters and on the mass of excited electrons.

  13. Self-assembly of Ge quantum dots on periodically corrugated Si surfaces

    International Nuclear Information System (INIS)

    Buljan, M.; Jerčinović, M.; Radić, N.; Facsko, S.; Baehtz, C.; Muecklich, A.; Grenzer, J.; Delač Marion, I.; Mikšić Trontl, V.; Kralj, M.; Holý, V.

    2015-01-01

    The fabrication of regularly ordered Ge quantum dot arrays on Si surfaces usually requires extensive preparation processing, ensuring clean and atomically ordered substrates, while the ordering parameters are quite limited by the surface properties of the substrate. Here, we demonstrate a simple method for fabrication of ordered Ge quantum dots with highly tunable ordering parameters on rippled Si surfaces. The ordering is achieved by magnetron sputter deposition, followed by an annealing in high vacuum. We show that the type of ordering and lattice vector parameters of the formed Ge quantum dot lattice are determined by the crystallographic properties of the ripples, i.e., by their shape and orientation. Moreover, the ordering is achieved regardless the initial amorphisation of the ripples surface and the presence of a thin oxide layer

  14. High-speed Si/GeSi hetero-structure Electro Absorption Modulator.

    Science.gov (United States)

    Mastronardi, L; Banakar, M; Khokhar, A Z; Hattasan, N; Rutirawut, T; Bucio, T Domínguez; Grabska, K M; Littlejohns, C; Bazin, A; Mashanovich, G; Gardes, F Y

    2018-03-19

    The ever-increasing demand for integrated, low power interconnect systems is pushing the bandwidth density of CMOS photonic devices. Taking advantage of the strong Franz-Keldysh effect in the C and L communication bands, electro-absorption modulators in Ge and GeSi are setting a new standard in terms of device footprint and power consumption for next generation photonics interconnect arrays. In this paper, we present a compact, low power electro-absorption modulator (EAM) Si/GeSi hetero-structure based on an 800 nm SOI overlayer with a modulation bandwidth of 56 GHz. The device design and fabrication tolerant process are presented, followed by the measurement analysis. Eye diagram measurements show a dynamic ER of 5.2 dB at a data rate of 56 Gb/s at 1566 nm, and calculated modulator power is 44 fJ/bit.

  15. Effect of Synthesis Procedure on Thermoelectric Property of SiGe Alloy

    Science.gov (United States)

    Li, Jing; Han, Jun; Jiang, Tao; Luo, Lili; Xiang, Yongchun

    2018-05-01

    SiGe thermoelectric material has been synthesized by ball milling combined with hot pressing (HP) or spark plasma sintering (SPS). Effects of ball milling time, powder to ball weight ratio and sintering method on microstructure and thermoelectric properties of SiGe are studied. The results show that longer ball milling time leads to decreased density and worse electrical properties. In the sintering process, SPS results in much larger density and better electrical properties than HP. The Si0.795Ge0.2B0.005 sample prepared by 2 h ball milling combined with SPS obtains a maximum power factor of 3.0 mW m-1 K-2 at 860 K and ZT of 0.95 at 1000 K.

  16. Morphological analysis of GeTe in inline phase change switches

    International Nuclear Information System (INIS)

    King, Matthew R.; El-Hinnawy, Nabil; Salmon, Mike; Gu, Jitty; Wagner, Brian P.; Jones, Evan B.; Howell, Robert S.; Nichols, Doyle T.; Young, Robert M.; Borodulin, Pavel

    2015-01-01

    Crystallization and amorphization phenomena in indirectly heated phase change material-based devices were investigated. Scanning transmission electron microscopy was utilized to explore GeTe phase transition processes in the context of the unique inline phase change switch (IPCS) architecture. A monolithically integrated thin film heating element successfully converted GeTe to ON and OFF states. Device cycling prompted the formation of an active area which sustains the majority of structural changes during pulsing. A transition region on both sides of the active area consisting of polycrystalline GeTe and small nuclei (<15 nm) in an amorphous matrix was also observed. The switching mechanism, determined by variations in pulsing parameters, was shown to be predominantly growth-driven. A preliminary model for crystallization and amorphization in IPCS devices is presented

  17. Photoreflectance Spectroscopy Characterization of Ge/Si0.16Ge0.84 Multiple Quantum Wells on Ge Virtual Substrate

    OpenAIRE

    Hsu, Hung-Pin; Yang, Pong-Hong; Huang, Jeng-Kuang; Wu, Po-Hung; Huang, Ying-Sheng; Li, Cheng; Huang, Shi-Hao; Tiong, Kwong-Kau

    2013-01-01

    We report a detailed characterization of a Ge/Si0.16Ge0.84 multiple quantum well (MQW) structure on Ge-on-Si virtual substrate (VS) grown by ultrahigh vacuum chemical vapor deposition by using temperature-dependent photoreflectance (PR) in the temperature range from 10 to 300 K. The PR spectra revealed a wide range of optical transitions from the MQW region as well as transitions corresponding to the light-hole and heavy-hole splitting energies of Ge-on-Si VS. A detailed comparison of PR spec...

  18. Strain relaxation of germanium-tin (GeSn) fins

    Science.gov (United States)

    Kang, Yuye; Huang, Yi-Chiau; Lee, Kwang Hong; Bao, Shuyu; Wang, Wei; Lei, Dian; Masudy-Panah, Saeid; Dong, Yuan; Wu, Ying; Xu, Shengqiang; Tan, Chuan Seng; Gong, Xiao; Yeo, Yee-Chia

    2018-02-01

    Strain relaxation of biaxially strained Ge1-xSnx layer when it is patterned into Ge1-xSnx fin structures is studied. Ge1-xSnx-on-insulator (GeSnOI) substrate was realized using a direct wafer bonding (DWB) technique and Ge1-xSnx fin structures were formed by electron beam lithography (EBL) patterning and dry etching. The strain in the Ge1-xSnx fins having fin widths (WFin) ranging from 1 μm down to 80 nm was characterized using micro-Raman spectroscopy. Raman measurements show that the strain relaxation increases with decreasing WFin. Finite element (FE) simulation shows that the strain component in the transverse direction relaxes with decreasing WFin, while the strain component along the fin direction remains unchanged. For various Ge1-xSnx fin widths, transverse strain relaxation was further extracted using micro-Raman spectroscopy, which is consistent with the simulation results.

  19. High spin states in 66,68Ge

    International Nuclear Information System (INIS)

    Hermkens, U.; Becker, F.; Eberth, J.; Freund, S.; Mylaeus, T.; Skoda, S.; Teichert, W.; Werth, A. v.d.

    1992-01-01

    High spin states of 66,68 Ge have been investigated at the FN Tandem accelerator of the University of Koeln via the reactions 40 Ca( 32 S,α2p,4p) 66,68 Ge at a beam energy of 100 MeV and 58 Ni( 16 O,α2p) 68 Ge at 65 MeV. The OSIRIS spectrometer with 12 escape suppressed Ge detectors was used to measure γγ coincidences and γ-ray angular distributions. In 66 Ge ( 68 Ge) 33 (22) new levels were found and 63 (62) new γ-transitions were placed in the level scheme. Both nuclei show a rather complicated but similar excitation pattern, ruled by the interplay of quasiparticle and collective degrees of freedom. The results are compared to the recently published EXVAM calculations for 68 Ge. (orig.)

  20. Status of NTD Ge bolometer material and devices

    International Nuclear Information System (INIS)

    Haller, E.E.; Haegel, N.M.; Park, I.S.

    1985-08-01

    This status report is a direct follow-up to the presentation given at the first IR Detector Technology Workshop which took place at NASA Ames Research Center on July 12 and 13, 1983. The conclusions which we presented at that meeting are still fully valid. In the meantime we have learned more about the physics of hopping conduction at very low temperatures which will be important for bolometer design and operation at ever decreasing temperatures. Resistivity measurements have been extended down to 50 mK. At such low temperatures, precise knowledge of the neutron capture cross sections sigma/sub n/ of the various Ge isotopes is critical if one is to make an accurate prediction of the dopant concentrations and compensation, and therefore resistivity, that will result from a given irradiation. We describe an empirical approach for obtaining the desired resistivity material and are in the process of conducting a set of experiments which will improve the knowledge of the effective sigma/sub n/ values for a given location in a particular reactor. A wider range of NTD Ge samples is now available. Noise measurements on bolometers with ion implanted contacts show that no 1/f noise component appears down to 1 Hz and probably lower. 4 refs., 5 figs

  1. Growth dynamics of SiGe nanowires by the Vapour Liquid Solid method and its impact on SiGe/Si axial heterojunction abruptness.

    Science.gov (United States)

    Pura, Jose Luis; Periwal, Priyanka; Baron, Thierry; Jimenez, Juan

    2018-06-05

    The Vapour Liquid Solid (VLS) method is by far the most extended procedure for bottom-up nanowire growth. This method also allows for the manufacture of nanowire axial heterojunctions in a straightforward way. To do this, during the growth process the precursor gases are switched on/off to obtain the desired change in the nanowire composition. Using this technique axially heterostructured nanowires can be grown, which are crucial for the fabrication of electronic and optoelectronic devices. SiGe/Si nanowires are compatible with Complementary Metal Oxide Semiconductor (CMOS) technology, this improves their versatility and the possibility of integration with the current electronic technologies. Abrupt heterointerfaces are fundamental for the development and correct operation of electronic and optoelectronic devices. Unfortunately, VLS growth of SiGe/Si heterojunctions does not provide abrupt transitions because of the high solubility of group IV semiconductors in Au, with the corresponding reservoir effect that precludes the growth of sharp interfaces. In this work, we studied the growth dynamics of SiGe/Si heterojunctions based on already developed models for VLS growth. A composition map of the Si-Ge-Au liquid alloy is proposed to better understand the impact of the growing conditions on the nanowire growth process and the heterojunction formation. The solution of our model provides heterojunction profiles in good agreement with experimental measurements. Finally, the in-depth study of the composition map provides a practical approach to reduce drastically the heterojunction abruptness by reducing the Si and Ge concentrations in the catalyst droplet. This converges with previous approaches that use catalysts aiming to reduce the solubility of the atomic species. This analysis opens new paths to reduce the heterojunction abruptness using Au catalysts, but the model can be naturally extended to other catalysts and semiconductors. © 2018 IOP Publishing Ltd.

  2. Physical characterization of Cu{sub 2}ZnGeSe{sub 4} thin films from annealing of Cu-Zn-Ge precursor layers

    Energy Technology Data Exchange (ETDEWEB)

    Buffière, M., E-mail: buffiere@imec.be [Imec—Partner in Solliance, Leuven (Belgium); Department of Electrical Engineering (ESAT), KU Leuven, Heverlee (Belgium); ElAnzeery, H. [Imec—Partner in Solliance, Leuven (Belgium); KACST-Intel Consortium Center of Excellence in Nano-manufacturing Applications (CENA), Riyadh (Saudi Arabia); Microelectronics System Design department, Nile University, Cairo (Egypt); Oueslati, S.; Ben Messaoud, K. [Imec—Partner in Solliance, Leuven (Belgium); KACST-Intel Consortium Center of Excellence in Nano-manufacturing Applications (CENA), Riyadh (Saudi Arabia); Department of Physics, Faculty of Sciences of Tunis, El Manar (Tunisia); Brammertz, G.; Meuris, M. [Imec Division IMOMEC — Partner in Solliance, Diepenbeek (Belgium); Institute for Material Research (IMO) Hasselt University, Diepenbeek (Belgium); Poortmans, J. [Imec—Partner in Solliance, Leuven (Belgium); Department of Electrical Engineering (ESAT), KU Leuven, Heverlee (Belgium)

    2015-05-01

    Cu{sub 2}ZnGeSe{sub 4} (CZGeSe) can be considered as a potential alternative for wide band gap thin film devices. In this work, CZGeSe thin films were deposited on Mo-coated soda lime glass substrates by sequential deposition of sputtered Cu, Zn and e-beam evaporated Ge layers from elemental targets followed by annealing at high temperature using H{sub 2}Se gas. We report on the effect of the precursor stack order and composition and the impact of the annealing temperature on the physical properties of CZGeSe thin films. The optimal layer morphology was obtained when using a Mo/Cu/Zn/Ge precursor stack annealed at 460 °C. We have observed that the formation of secondary phases such as ZnSe can be prevented by tuning the initial composition of the stack, the stack order and the annealing conditions. This synthesis process allows synthesizing CZGeSe absorber with an optical band gap of 1.5 eV. - Highlights: • Cu{sub 2}ZnGeSe{sub 4} (CZGeSe) thin films were deposited using a two-step process. • CZGeSe dense layers were obtained using a Mo/Cu/Zn/Ge precursor annealed at 460 °C. • Formation of ZnSe can be avoided by tuning the composition and order of the initial stack. • P-type CZGeSe absorber with an optical band gap of 1.5 eV was obtained.

  3. Nanoscale interfacial engineering to grow Ge on Si as virtual substrates and subsequent integration of GaAs

    Energy Technology Data Exchange (ETDEWEB)

    Leonhardt, Darin [Department of Chemical and Nuclear Engineering, University of New Mexico, Albuquerque, NM 87131 (United States); Sheng, Josephine; Cederberg, Jeffrey G.; Li Qiming; Carroll, Malcolm S. [Sandia National Laboratories, Albuquerque, NM 87185 (United States); Han, Sang M., E-mail: meister@unm.ed [Department of Chemical and Nuclear Engineering, University of New Mexico, Albuquerque, NM 87131 (United States)

    2010-08-31

    We have demonstrated the scalability of a process previously dubbed as Ge 'touchdown' on Si to substantially reduce threading dislocations below 10{sup 7}/cm{sup 2} in a Ge film grown on a 2 inch-diameter chemically oxidized Si substrate. This study also elucidates the overall mechanism of the touchdown process. The 1.4 nm thick chemical oxide is first formed by immersing Si substrates in a solution of H{sub 2}O{sub 2} and H{sub 2}SO{sub 4}. Subsequent exposure to Ge flux creates 3 to 7 nm-diameter voids in the oxide at a density greater than 10{sup 11}/cm{sup 2}. Comparison of data taken from many previous studies and ours shows an exponential dependence between oxide thickness and inverse temperature of void formation. Additionally, exposure to a Ge or Si atom flux decreases the temperature at which voids begin to form in the oxide. These results strongly suggest that Ge actively participates in the reaction with SiO{sub 2} in the void formation process. Once voids are created in the oxide under a Ge flux, Ge islands selectively nucleate within the void openings on the newly exposed Si. Island nucleation and growth then compete with the void growth reaction. At substrate temperatures between 823 and 1053 K, nanometer size Ge islands that nucleate within the voids continue to grow and coalesce into a continuous film over the remaining oxide. Coalescence of the Ge islands is believed to result in the creation of stacking faults in the Ge film at a density of 5 x 10{sup 7}/cm{sup 2}. Additionally, coalescence results in films of 3 {mu}m thickness having a root-mean-square roughness of 8 to 10 nm. We have found that polishing the films with dilute H{sub 2}O{sub 2} results in roughness values below 0.5 nm. However, stacking faults originating at the Ge-SiO{sub 2} interface and terminating at the Ge surface are polished at a slightly reduced rate, and show up as 1 to 2 nm raised lines on the polished Ge surface. These lines are then transferred into the

  4. Nanoscale interfacial engineering to grow Ge on Si as virtual substrates and subsequent integration of GaAs

    International Nuclear Information System (INIS)

    Leonhardt, Darin; Sheng, Josephine; Cederberg, Jeffrey G.; Li Qiming; Carroll, Malcolm S.; Han, Sang M.

    2010-01-01

    We have demonstrated the scalability of a process previously dubbed as Ge 'touchdown' on Si to substantially reduce threading dislocations below 10 7 /cm 2 in a Ge film grown on a 2 inch-diameter chemically oxidized Si substrate. This study also elucidates the overall mechanism of the touchdown process. The 1.4 nm thick chemical oxide is first formed by immersing Si substrates in a solution of H 2 O 2 and H 2 SO 4 . Subsequent exposure to Ge flux creates 3 to 7 nm-diameter voids in the oxide at a density greater than 10 11 /cm 2 . Comparison of data taken from many previous studies and ours shows an exponential dependence between oxide thickness and inverse temperature of void formation. Additionally, exposure to a Ge or Si atom flux decreases the temperature at which voids begin to form in the oxide. These results strongly suggest that Ge actively participates in the reaction with SiO 2 in the void formation process. Once voids are created in the oxide under a Ge flux, Ge islands selectively nucleate within the void openings on the newly exposed Si. Island nucleation and growth then compete with the void growth reaction. At substrate temperatures between 823 and 1053 K, nanometer size Ge islands that nucleate within the voids continue to grow and coalesce into a continuous film over the remaining oxide. Coalescence of the Ge islands is believed to result in the creation of stacking faults in the Ge film at a density of 5 x 10 7 /cm 2 . Additionally, coalescence results in films of 3 μm thickness having a root-mean-square roughness of 8 to 10 nm. We have found that polishing the films with dilute H 2 O 2 results in roughness values below 0.5 nm. However, stacking faults originating at the Ge-SiO 2 interface and terminating at the Ge surface are polished at a slightly reduced rate, and show up as 1 to 2 nm raised lines on the polished Ge surface. These lines are then transferred into the subsequent growth morphology of GaAs deposited by metal-organic chemical vapor

  5. C and Si delta doping in Ge by CH_3SiH_3 using reduced pressure chemical vapor deposition

    International Nuclear Information System (INIS)

    Yamamoto, Yuji; Ueno, Naofumi; Sakuraba, Masao; Murota, Junichi; Mai, Andreas; Tillack, Bernd

    2016-01-01

    C and Si delta doping in Ge are investigated using a reduced pressure chemical vapor deposition system to establish atomic-order controlled processes. CH_3SiH_3 is exposed at 250 °C to 500 °C to a Ge on Si (100) substrate using H_2 or N_2 carrier gas followed by a Ge cap layer deposition. At 350 °C, C and Si are uniformly adsorbed on the Ge surface and the incorporated C and Si form steep delta profiles below detection limit of SIMS measurement. By using N_2 as carrier gas, the incorporated C and Si doses in Ge are saturated at one mono-layer below 350 °C. At this temperature range, the incorporated C and Si doses are nearly the same, indicating CH_3SiH_3 is adsorbed on the Ge surface without decomposing the C−Si bond. On the other hand, by using H_2 as carrier gas, lower incorporated C is observed in comparison to Si. CH_3SiH_3 injected with H_2 carrier gas is adsorbed on Ge without decomposing the C−Si bond and the adsorbed C is reduced by dissociation of the C−Si bond during temperature ramp up to 550 °C. The adsorbed C is maintained on the Ge surface in N_2 at 550 °C. - Highlights: • C and Si delta doping in Ge is investigated using RPCVD system by CH_3SiH_3 exposure. • Atomically flat C and Si delta layers are fabricated at 350 °C. • Incorporated C and Si doses are saturated at one mono-layer below 350 °C. • CH_3SiH_3 adsorption occurred without decomposing C−Si bond. • Adsorbed C is desorbed due to dissociation by hydrogen during postannealing at 550 °C.

  6. Phase formation and texture of thin nickel germanides on Ge(001) and Ge(111)

    Energy Technology Data Exchange (ETDEWEB)

    De Schutter, B., E-mail: deschutter.bob@ugent.be; Detavernier, C. [Department of Solid-State Sciences, Ghent University, Krijgslaan 281/S1, 9000 Ghent (Belgium); Van Stiphout, K.; Santos, N. M.; Vantomme, A. [Instituut voor Kern- en Stralingsfysica, KU Leuven, Celestijnenlaan 200 D, B-3001 Leuven (Belgium); Bladt, E.; Bals, S. [Electron Microscopy for Materials Research (EMAT), University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); Jordan-Sweet, J.; Lavoie, C. [IBM T.J. Watson Research Center, Yorktown Heights, New York 10598 (United States); Comrie, C. M. [Department of Physics, University of Cape Town, Rondebosch 7700 (South Africa)

    2016-04-07

    We studied the solid-phase reaction between a thin Ni film and a single crystal Ge(001) or Ge(111) substrate during a ramp anneal. The phase formation sequence was determined using in situ X-ray diffraction and in situ Rutherford backscattering spectrometry (RBS), while the nature and the texture of the phases were studied using X-ray pole figures and transmission electron microscopy. The phase sequence is characterized by the formation of a single transient phase before NiGe forms as the final and stable phase. X-ray pole figures were used to unambiguously identify the transient phase as the ϵ-phase, a non-stoichiometric Ni-rich germanide with a hexagonal crystal structure that can exist for Ge concentrations between 34% and 48% and which forms with a different epitaxial texture on both substrate orientations. The complementary information gained from both RBS and X-ray pole figure measurements revealed a simultaneous growth of both the ϵ-phase and NiGe over a small temperature window on both substrate orientations.

  7. Amorphous inclusions during Ge and GeSn epitaxial growth via chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Gencarelli, F., E-mail: federica.gencarelli@imec.be [imec, Kapeldreef 75, 3001 Leuven (Belgium); Dept. of Metallurgy and Materials Engineering, KU Leuven, B-3001 Leuven (Belgium); Shimura, Y. [imec, Kapeldreef 75, 3001 Leuven (Belgium); Nuclear and Radiation Physics Section, KU Leuven, B-3001 Leuven (Belgium); Kumar, A. [imec, Kapeldreef 75, 3001 Leuven (Belgium); Nuclear and Radiation Physics Section, KU Leuven, B-3001 Leuven (Belgium); Vincent, B.; Moussa, A.; Vanhaeren, D.; Richard, O.; Bender, H. [imec, Kapeldreef 75, 3001 Leuven (Belgium); Vandervorst, W. [imec, Kapeldreef 75, 3001 Leuven (Belgium); Nuclear and Radiation Physics Section, KU Leuven, B-3001 Leuven (Belgium); Caymax, M.; Loo, R. [imec, Kapeldreef 75, 3001 Leuven (Belgium); Heyns, M. [imec, Kapeldreef 75, 3001 Leuven (Belgium); Dept. of Metallurgy and Materials Engineering, KU Leuven, B-3001 Leuven (Belgium)

    2015-09-01

    In this work, we discuss the characteristics of particular island-type features with an amorphous core that are developed during the low temperature epitaxial growth of Ge and GeSn layers by means of chemical vapor deposition with Ge{sub 2}H{sub 6}. Although further investigations are needed to unambiguously identify the origin of these features, we suggest that they are originated by the formation of clusters of H and/or contaminants atoms during growth. These would initially cause the formation of pits with crystalline rough facets over them, resulting in ring-shaped islands. Then, when an excess surface energy is overcome, an amorphous phase would nucleate inside the pits and fill them. Reducing the pressure and/or increasing the growth temperature can be effective ways to prevent the formation of these features, likely due to a reduction of the surface passivation from H and/or contaminant atoms. - Highlights: • Island features with amorphous cores develop during low T Ge(Sn) CVD with Ge{sub 2}H{sub 6.} • These features are thoroughly characterized in order to understand their origin. • A model is proposed to describe the possible evolution of these features. • Lower pressures and/or higher temperatures avoid the formation of these features.

  8. Multi-photon production in $e^{+}e^{-}$ collisions at $\\sqrt{s}$= 183 GeV

    CERN Document Server

    Ackerstaff, K.; Allison, John; Altekamp, N.; Anderson, K.J.; Anderson, S.; Arcelli, S.; Asai, S.; Ashby, S.F.; Axen, D.; Azuelos, G.; Ball, A.H.; Barberio, E.; Barlow, Roger J.; Bartoldus, R.; Batley, J.R.; Baumann, S.; Bechtluft, J.; Behnke, T.; Bell, Kenneth Watson; Bella, G.; Bentvelsen, S.; Bethke, S.; Betts, S.; Biebel, O.; Biguzzi, A.; Bird, S.D.; Blobel, V.; Bloodworth, I.J.; Bobinski, M.; Bock, P.; Bohme, J.; Boutemeur, M.; Braibant, S.; Bright-Thomas, P.; Brown, Robert M.; Burckhart, H.J.; Burgard, C.; Burgin, R.; Capiluppi, P.; Carnegie, R.K.; Carter, A.A.; Carter, J.R.; Chang, C.Y.; Charlton, David G.; Chrisman, D.; Ciocca, C.; Clarke, P.E.L.; Clay, E.; Cohen, I.; Conboy, J.E.; Cooke, O.C.; Couyoumtzelis, C.; Coxe, R.L.; Cuffiani, M.; Dado, S.; Dallavalle, G.Marco; Davis, R.; De Jong, S.; del Pozo, L.A.; de Roeck, A.; Desch, K.; Dienes, B.; Dixit, M.S.; Doucet, M.; Dubbert, J.; Duchovni, E.; Duckeck, G.; Duerdoth, I.P.; Eatough, D.; Estabrooks, P.G.; Etzion, E.; Evans, H.G.; Fabbri, F.; Fanfani, A.; Fanti, M.; Faust, A.A.; Fiedler, F.; Fierro, M.; Fischer, H.M.; Fleck, I.; Folman, R.; Furtjes, A.; Futyan, D.I.; Gagnon, P.; Gary, J.W.; Gascon, J.; Gascon-Shotkin, S.M.; Geich-Gimbel, C.; Geralis, T.; Giacomelli, G.; Giacomelli, P.; Gibson, V.; Gibson, W.R.; Gingrich, D.M.; Glenzinski, D.; Goldberg, J.; Gorn, W.; Grandi, C.; Gross, E.; Grunhaus, J.; Gruwe, M.; Hanson, G.G.; Hansroul, M.; Hapke, M.; Hargrove, C.K.; Hartmann, C.; Hauschild, M.; Hawkes, C.M.; Hawkings, R.; Hemingway, R.J.; Herndon, M.; Herten, G.; Heuer, R.D.; Hildreth, M.D.; Hill, J.C.; Hillier, S.J.; Hobson, P.R.; Hocker, James Andrew; Homer, R.J.; Honma, A.K.; Horvath, D.; Hossain, K.R.; Howard, R.; Huntemeyer, P.; Igo-Kemenes, P.; Imrie, D.C.; Ishii, K.; Jacob, F.R.; Jawahery, A.; Jeremie, H.; Jimack, M.; Joly, A.; Jones, C.R.; Jovanovic, P.; Junk, T.R.; Karlen, D.; Kartvelishvili, V.; Kawagoe, K.; Kawamoto, T.; Kayal, P.I.; Keeler, R.K.; Kellogg, R.G.; Kennedy, B.W.; Klier, A.; Kluth, S.; Kobayashi, T.; Kobel, M.; Koetke, D.S.; Kokott, T.P.; Kolrep, M.; Komamiya, S.; Kowalewski, Robert V.; Kress, T.; Krieger, P.; von Krogh, J.; Kyberd, P.; Lafferty, G.D.; Lanske, D.; Lauber, J.; Lautenschlager, S.R.; Lawson, I.; Layter, J.G.; Lazic, D.; Lee, A.M.; Lefebvre, E.; Lellouch, D.; Letts, J.; Levinson, L.; Liebisch, R.; List, B.; Littlewood, C.; Lloyd, A.W.; Lloyd, S.L.; Loebinger, F.K.; Long, G.D.; Losty, M.J.; Ludwig, J.; Lui, D.; Macchiolo, A.; Macpherson, A.; Mannelli, M.; Marcellini, S.; Markopoulos, C.; Martin, A.J.; Martin, J.P.; Martinez, G.; Mashimo, T.; Mattig, Peter; McDonald, W.John; McKenna, J.; Mckigney, E.A.; McMahon, T.J.; McPherson, R.A.; Meijers, F.; Menke, S.; Merritt, F.S.; Mes, H.; Meyer, J.; Michelini, A.; Mihara, S.; Mikenberg, G.; Miller, D.J.; Mir, R.; Mohr, W.; Montanari, A.; Mori, T.; Nagai, K.; Nakamura, I.; Neal, H.A.; Nellen, B.; Nisius, R.; O'Neale, S.W.; Oakham, F.G.; Odorici, F.; Ogren, H.O.; Oreglia, M.J.; Orito, S.; Palinkas, J.; Pasztor, G.; Pater, J.R.; Patrick, G.N.; Patt, J.; Perez-Ochoa, R.; Petzold, S.; Pfeifenschneider, P.; Pilcher, J.E.; Pinfold, J.; Plane, David E.; Poffenberger, P.; Poli, B.; Polok, J.; Przybycien, M.; Rembser, C.; Rick, H.; Robertson, S.; Robins, S.A.; Rodning, N.; Roney, J.M.; Roscoe, K.; Rossi, A.M.; Rozen, Y.; Runge, K.; Runolfsson, O.; Rust, D.R.; Sachs, K.; Saeki, T.; Sahr, O.; Sang, W.M.; Sarkisian, E.K.G.; Sbarra, C.; Schaile, A.D.; Schaile, O.; Scharf, F.; Scharff-Hansen, P.; Schieck, J.; Schmitt, B.; Schmitt, S.; Schoning, A.; Schorner, T.; Schroder, Matthias; Schumacher, M.; Schwick, C.; Scott, W.G.; Seuster, R.; Shears, T.G.; Shen, B.C.; Shepherd-Themistocleous, C.H.; Sherwood, P.; Siroli, G.P.; Sittler, A.; Skuja, A.; Smith, A.M.; Snow, G.A.; Sobie, R.; Soldner-Rembold, S.; Sproston, M.; Stahl, A.; Stephens, K.; Steuerer, J.; Stoll, K.; Strom, David M.; Strohmer, R.; Tafirout, R.; Talbot, S.D.; Tanaka, S.; Taras, P.; Tarem, S.; Teuscher, R.; Thiergen, M.; Thomson, M.A.; von Torne, E.; Torrence, E.; Towers, S.; Trigger, I.; Trocsanyi, Z.; Tsur, E.; Turcot, A.S.; Turner-Watson, M.F.; Van Kooten, Rick J.; Vannerem, P.; Verzocchi, M.; Vikas, P.; Voss, H.; Wackerle, F.; Wagner, A.; Ward, C.P.; Ward, D.R.; Watkins, P.M.; Watson, A.T.; Watson, N.K.; Wells, P.S.; Wermes, N.; White, J.S.; Wilson, G.W.; Wilson, J.A.; Wyatt, T.R.; Yamashita, S.; Yekutieli, G.; Zacek, V.; Zer-Zion, D.

    1998-01-01

    The process e+e- to gamma gamma (gamma) is studied using data recorded with the OPAL detector at LEP. The data sample corresponds to a total integrated luminosity of 56.2 pb-1 taken at a centre-of-mass energy of 183 GeV. The measured cross-section agrees well with the expectation from QED. A fit to the angular distribution is used to obtain improved limits at 95% CL on the QED cut-off parameters: Lambda+ > 233 GeV and Lambda- > 265 GeV as well as a mass limit for an excited electron, M(e*) > 227 GeV assuming equal e*egamma and eegamma couplings. No evidence for resonance production is found in the invariant mass spectrum of photon pairs. Limits are obtained for the cross-section times branching ratio for a resonance decaying into two photons.

  9. Multi-photon final states in $e^+ e^-$ collisions at $\\sqrt{s}$ = 130-172 GeV

    CERN Document Server

    Ackerstaff, K; Allison, J; Altekamp, N; Anderson, K J; Anderson, S; Arcelli, S; Asai, S; Axen, D A; Azuelos, Georges; Ball, A H; Barberio, E; Barlow, R J; Bartoldus, R; Batley, J Richard; Baumann, S; Bechtluft, J; Beeston, C; Behnke, T; Bell, A N; Bell, K W; Bella, G; Bentvelsen, Stanislaus Cornelius Maria; Bethke, Siegfried; Biebel, O; Biguzzi, A; Bird, S D; Blobel, Volker; Bloodworth, Ian J; Bloomer, J E; Bobinski, M; Bock, P; Bonacorsi, D; Boutemeur, M; Bouwens, B T; Braibant, S; Brigliadori, L; Brown, R M; Burckhart, Helfried J; Burgard, C; Bürgin, R; Capiluppi, P; Carnegie, R K; Carter, A A; Carter, J R; Chang, C Y; Charlton, D G; Chrisman, D; Clarke, P E L; Cohen, I; Conboy, J E; Cooke, O C; Cuffiani, M; Dado, S; Dallapiccola, C; Dallavalle, G M; Davis, R; De Jong, S; del Pozo, L A; Desch, Klaus; Dienes, B; Dixit, M S; do Couto e Silva, E; Doucet, M; Duchovni, E; Duckeck, G; Duerdoth, I P; Eatough, D; Edwards, J E G; Estabrooks, P G; Evans, H G; Evans, M; Fabbri, Franco Luigi; Fanti, M; Faust, A A; Fiedler, F; Fierro, M; Fischer, H M; Fleck, I; Folman, R; Fong, D G; Foucher, M; Fürtjes, A; Futyan, D I; Gagnon, P; Gary, J W; Gascon, J; Gascon-Shotkin, S M; Geddes, N I; Geich-Gimbel, C; Geralis, T; Giacomelli, G; Giacomelli, P; Giacomelli, R; Gibson, V; Gibson, W R; Gingrich, D M; Glenzinski, D A; Goldberg, J; Goodrick, M J; Gorn, W; Grandi, C; Gross, E; Grunhaus, Jacob; Gruwé, M; Hajdu, C; Hanson, G G; Hansroul, M; Hapke, M; Hargrove, C K; Hart, P A; Hartmann, C; Hauschild, M; Hawkes, C M; Hawkings, R; Hemingway, Richard J; Herndon, M; Herten, G; Heuer, R D; Hildreth, M D; Hill, J C; Hillier, S J; Hobson, P R; Homer, R James; Honma, A K; Horváth, D; Hossain, K R; Howard, R; Hüntemeyer, P; Hutchcroft, D E; Igo-Kemenes, P; Imrie, D C; Ingram, M R; Ishii, K; Jawahery, A; Jeffreys, P W; Jeremie, H; Jimack, Martin Paul; Joly, A; Jones, C R; Jones, G; Jones, M; Jost, U; Jovanovic, P; Junk, T R; Karlen, D A; Kartvelishvili, V G; Kawagoe, K; Kawamoto, T; Kayal, P I; Keeler, Richard K; Kellogg, R G; Kennedy, B W; Kirk, J; Klier, A; Kluth, S; Kobayashi, T; Kobel, M; Koetke, D S; Kokott, T P; Kolrep, M; Komamiya, S; Kress, T; Krieger, P; Von Krogh, J; Kyberd, P; Lafferty, G D; Lahmann, R; Lai, W P; Lanske, D; Lauber, J; Lautenschlager, S R; Layter, J G; Lazic, D; Lee, A M; Lefebvre, E; Lellouch, Daniel; Letts, J; Levinson, L; Lloyd, S L; Loebinger, F K; Long, G D; Losty, Michael J; Ludwig, J; Macchiolo, A; MacPherson, A L; Mannelli, M; Marcellini, S; Markus, C; Martin, A J; Martin, J P; Martínez, G; Mashimo, T; Mättig, P; McDonald, W J; McKenna, J A; McKigney, E A; McMahon, T J; McPherson, R A; Meijers, F; Menke, S; Merritt, F S; Mes, H; Meyer, J; Michelini, Aldo; Mikenberg, G; Miller, D J; Mincer, A; Mir, R; Mohr, W; Montanari, A; Mori, T; Morii, M; Müller, U; Mihara, S; Nagai, K; Nakamura, I; Neal, H A; Nellen, B; Nisius, R; O'Neale, S W; Oakham, F G; Odorici, F; Ögren, H O; Oh, A; Oldershaw, N J; Oreglia, M J; Orito, S; Pálinkás, J; Pásztor, G; Pater, J R; Patrick, G N; Patt, J; Pearce, M J; Pérez-Ochoa, R; Petzold, S; Pfeifenschneider, P; Pilcher, J E; Pinfold, J L; Plane, D E; Poffenberger, P R; Poli, B; Posthaus, A; Rees, D L; Rigby, D; Robertson, S; Robins, S A; Rodning, N L; Roney, J M; Rooke, A M; Ros, E; Rossi, A M; Routenburg, P; Rozen, Y; Runge, K; Runólfsson, O; Ruppel, U; Rust, D R; Rylko, R; Sachs, K; Saeki, T; Sarkisyan-Grinbaum, E; Sbarra, C; Schaile, A D; Schaile, O; Scharf, F; Scharff-Hansen, P; Schenk, P; Schieck, J; Schleper, P; Schmitt, B; Schmitt, S; Schöning, A; Schröder, M; Schultz-Coulon, H C; Schumacher, M; Schwick, C; Scott, W G; Shears, T G; Shen, B C; Shepherd-Themistocleous, C H; Sherwood, P; Siroli, G P; Sittler, A; Skillman, A; Skuja, A; Smith, A M; Snow, G A; Sobie, Randall J; Söldner-Rembold, S; Springer, R W; Sproston, M; Stephens, K; Steuerer, J; Stockhausen, B; Stoll, K; Strom, D; Szymanski, P; Tafirout, R; Talbot, S D; Tanaka, S; Taras, P; Tarem, S; Teuscher, R; Thiergen, M; Thomson, M A; Von Törne, E; Towers, S; Trigger, I; Trócsányi, Z L; Tsur, E; Turcot, A S; Turner-Watson, M F; Utzat, P; Van Kooten, R; Verzocchi, M; Vikas, P; Vokurka, E H; Voss, H; Wäckerle, F; Wagner, A; Ward, C P; Ward, D R; Watkins, P M; Watson, A T; Watson, N K; Wells, P S; Wermes, N; White, J S; Wilkens, B; Wilson, G W; Wilson, J A; Wolf, G; Wyatt, T R; Yamashita, S; Yekutieli, G; Zacek, V; Zer-Zion, D

    1998-01-01

    The process e^+e^- -> gamma gamma (gamma) is studied using data recorded with the OPAL detector at LEP. The data sample corresponds to a total integrated luminosity of 25.38 pb^{-1} taken at centre-of-mass energies of 130-172 GeV. The measured cross-sections agree well with the expectation from QED. In a combined fit using data from all centre-of-mass energies, the angular distribution is used to obtain improved limits on the cut-off parameters: Lambda_+ > 195 GeV and Lambda_- > 210 GeV (95% CL). In addition, limits on non-standard e^+e^-gamma couplings and contact interactions, as well as a 95% CL mass limit for an excited electron, M_{e^*} > 194 GeV for an e^+e^-gamma coupling kappa = 1, are determined.

  10. Dislocation reduction in heteroepitaxial Ge on Si using SiO{sub 2} lined etch pits and epitaxial lateral overgrowth

    Energy Technology Data Exchange (ETDEWEB)

    Leonhardt, Darin; Han, Sang M. [Department of Chemical and Nuclear Engineering, University of New Mexico, Albuquerque, New Mexico 87131 (United States)

    2011-09-12

    We report a technique that significantly reduces threading dislocations in Ge on Si heteroepitaxy. Germanium is first grown on Si and etched to produce pits in the surface where threading dislocations terminate. Further processing leaves a layer of SiO{sub 2} only within etch pits. Subsequent selective epitaxial Ge growth results in coalescence above the SiO{sub 2}. The SiO{sub 2} blocks the threading dislocations from propagating into the upper Ge epilayer. With annealed Ge films grown on Si, the said method reduces the defect density from 2.6 x 10{sup 8} to 1.7 x 10{sup 6} cm{sup -2}, potentially making the layer suitable for electronic and photovoltaic devices.

  11. Theoretical scenarios for 103 GeV to 1019 GeV

    International Nuclear Information System (INIS)

    Kaul, R.K.

    1996-01-01

    Basic dogmas of particle physics are reviewed. Some of their implications beyond the standard model are explored. Higgs sector of the standard model of electroweak interactions is the weakest link in the model. Elementary Higgs field makes the model unnatural beyond about 10 3 GeV. Supersymmetry provides the most attractive framework where in this problem can be addressed. This new symmetry, relating fermions and bosons, is expected to be operative at about 10 3 GeV. In addition, grand unification of the fundamental interactions can be studied consistently only within a supersymmetric formulation. Inclusion of gravity with other interactions leads to supergravity theories, which should emerge as a low energy description of a more fundamental theory, the string-theory. Supersymmetry again is an essential feature of such a theory. Quantum gravity, with its characteristic scale of 10 19 GeV, may well be described by a superstring theory. (author). 28 refs., 1 fig

  12. Electron-electron interaction in p-SiGe/Ge quantum wells

    International Nuclear Information System (INIS)

    Roessner, Benjamin; Kaenel, Hans von; Chrastina, Daniel; Isella, Giovanni; Batlogg, Bertram

    2005-01-01

    The temperature dependent magnetoresistance of high mobility p-SiGe/Ge quantum wells is studied with hole densities ranging from 1.7 to 5.9 x 10 11 cm -2 . At magnetic fields below the onset of quantum oscillations that reflect the high mobility values (up to 75000 cm 2 /Vs), we observe the clear signatures of electron-electron interaction. We compare our experiment with the theory of electron-electron interaction including the Zeeman band splitting. The observed magnetoresistance is well explained as a superposition of band structure induced positive magnetoresistance and the negative magntoresistance due to the electron-electron interaction effect

  13. Background components of Ge(Li) and GeHP-detectors in the passive shield

    International Nuclear Information System (INIS)

    Buraeva, E.A.; Davydov, M.G.; Zorina, L.V.; Stasov, V.V.

    2007-01-01

    The gamma-spectrometer Ge(Li)- and the extra pure Ge-detector background components in a specially designed passive shield were subjected to investigation in the land-based laboratory in 1996-2006. The measurement time period varied from 45 up to 240 hours. The detector background is caused by the radionuclides in the shield material, in the shield cells and in the detector materials. The prominence was given to the study of the revealed time dependence of 222 Rn daughter product background including '2 10 Pb 46.5 keV peak [ru

  14. Effect of Ge surface termination on oxidation behavior

    Science.gov (United States)

    Lee, Younghwan; Park, Kibyung; Cho, Yong Soo; Lim, Sangwoo

    2008-09-01

    Sulfur-termination was formed on the Ge(1 0 0) surface using (NH 4) 2S solution. Formation of Ge-S and the oxidation of the S-terminated Ge surface were monitored with multiple internal reflection Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. In the 0.5, 5, or 20% (NH 4) 2S solution, H-termination on the Ge(1 0 0) surface was substituted with S-termination in 1 min. When the S-terminated Ge(1 0 0) surface was exposed in air ambient, the oxidation was retarded for about 3600 min. The preservation time of the oxide layer up to one monolayer of S-terminated Ge(1 0 0) surface was about 120 times longer than for the H-terminated Ge(1 0 0) surface. However, the oxidation of S-terminated Ge(1 0 0) surface drastically increased after the threshold time. There was no significant difference in threshold time between S-terminations formed in 0.5, 5, and 20% (NH 4) 2S solutions. With the surface oxidation, desorption of S on the Ge surface was observed. The desorption behavior of sulfur on the S-terminated Ge(1 0 0) surface was independent of the concentration of the (NH 4) 2S solution that forms S-termination. Non-ideal S-termination on Ge surfaces may be related to drastic oxidation of the Ge surface. Finally, with the desulfurization on the S-terminated Ge(1 0 0) surface, oxide growth is accelerated.

  15. Role of the SiO2 buffer layer thickness in the formation of Si/SiO2/nc-Ge/SiO2 structures by dry oxidation

    International Nuclear Information System (INIS)

    Kling, A.; Ortiz, M.I.; Prieto, A.C.; Rodriguez, A.; Rodriguez, T.; Jimenez, J.; Ballesteros, C.; Soares, J.C.

    2006-01-01

    Nanomemories, containing Ge-nanoparticles in a SiO 2 matrix, can be produced by dry thermal oxidation of a SiGe layer deposited onto a Si-wafer with a barrier SiO 2 layer on its top. Rutherford backscattering spectrometry has been used to characterize the kinetics of the oxidation process, the composition profile of the growing oxide, the Ge-segregation and its diffusion into the barrier oxide in samples with thin and thick barrier oxide layers. The Ge segregated during the oxidation of the SiGe layer diffuses into the barrier oxide. In the first case the diffusion through the thin oxide is enhanced by the proximity of the substrate that acts as a sink for the Ge, resulting in the formation of a low Ge concentration SiGe layer in the surface of the Si-wafer. In the second case, the Ge-diffusion progresses as slowly as in bulk SiO 2 . Since barrier oxide layers as thin as possible are favoured for device fabrication, the structures should be oxidized at lower temperatures and the initial SiGe layer thickness reduced to minimize the Ge-diffusion

  16. XRD analysis of strained Ge-SiGe heterostructures on relaxed SiGe graded buffers grown by hybrid epitaxy on Si(0 0 1) substrates

    International Nuclear Information System (INIS)

    Franco, N.; Barradas, N.P.; Alves, E.; Vallera, A.M.; Morris, R.J.H.; Mironov, O.A.; Parker, E.H.C.

    2005-01-01

    Ge/Si 1-x Ge x inverted modulation doped heterostructures with Ge channel thickness of 16 and 20 nm were grown by a method of hybrid epitaxy followed by ex situ annealing at 650 deg. C for p-HMOS application. The thicker layers of the virtual substrate (6000 nm graded SiGe up to x = 0.6 and 1000 nm uniform composition with x = 0.6) were produced by ultrahigh vacuum chemical vapor deposition (UHV-CVD) while the thinner, Si(2 nm)-SiGe(20 nm)-Ge-SiGe(15 nm + 5 nm B-doped + 20 nm) active layers were grown by low temperature solid-source (LT-SS) MBE at T = 350 deg. C. As-grown and annealed samples were measured by X-ray diffraction (XRD). Reciprocal space maps (RSMs) allowed us to determine non-destructively the precise composition (∼1%) and strain of the Ge channel, along with similar information regarding the other layers that made up the whole structure. Layer thickness was determined with complementary high-resolution Rutherford backscattering (RBS) experiments

  17. Shell morphology and Raman spectra of epitaxial Ge-SixGe1-x and Si-SixGe1-x core-shell nanowires

    Science.gov (United States)

    Wen, Feng; Dillen, David C.; Kim, Kyounghwan; Tutuc, Emanuel

    2017-06-01

    We investigate the shell morphology and Raman spectra of epitaxial Ge-SixGe1-x and Si-SixGe1-x core-shell nanowire heterostructures grown using a combination of a vapor-liquid-solid (VLS) growth mechanism for the core, followed by in-situ epitaxial shell growth using ultra-high vacuum chemical vapor deposition. Cross-sectional transmission electron microscopy reveals that the VLS growth yields cylindrical Ge, and Si nanowire cores grown along the ⟨111⟩, and ⟨110⟩ or ⟨112⟩ directions, respectively. A hexagonal cross-sectional morphology is observed for Ge-SixGe1-x core-shell nanowires terminated by six {112} facets. Two distinct morphologies are observed for Si-SixGe1-x core-shell nanowires that are either terminated by four {111} and two {100} planes associated with the ⟨110⟩ growth direction or four {113} and two {111} planes associated with the ⟨112⟩ growth direction. We show that the Raman spectra of Si- SixGe1-x are correlated with the shell morphology thanks to epitaxial growth-induced strain, with the core Si-Si mode showing a larger red shift in ⟨112⟩ core-shell nanowires compared to their ⟨110⟩ counterparts. We compare the Si-Si Raman mode value with calculations based on a continuum elasticity model coupled with the lattice dynamic theory.

  18. Room Temperature Electroluminescence from Tensile-Strained Si0.13Ge0.87/Ge Multiple Quantum Wells on a Ge Virtual Substrate

    Directory of Open Access Journals (Sweden)

    Guangyang Lin

    2016-09-01

    Full Text Available Direct band electroluminescence (EL from tensile-strained Si0.13Ge0.87/Ge multiple quantum wells (MQWs on a Ge virtual substrate (VS at room temperature is reported herein. Due to the competitive result of quantum confinement Stark effect and bandgap narrowing induced by tensile strain in Ge wells, electroluminescence from Γ1-HH1 transition in 12-nm Ge wells was observed at around 1550 nm. As injection current density increases, additional emission shoulders from Γ2-HH2 transition in Ge wells and Ge VS appeared at around 1300–1400 nm and 1600–1700 nm, respectively. The peak energy of EL shifted to the lower energy side superquadratically with an increase of injection current density as a result of the Joule heating effect. During the elevation of environmental temperature, EL intensity increased due to a reduction of energy between L and Γ valleys of Ge. Empirical fitting of the relationship between the integrated intensity of EL (L and injection current density (J with L~Jm shows that the m factor increased with injection current density, suggesting higher light emitting efficiency of the diode at larger injection current densities, which can be attributed to larger carrier occupations in the Γ valley and the heavy hole (HH valance band at higher temperatures.

  19. Graphene growth on Ge(100)/Si(100) substrates by CVD method.

    Science.gov (United States)

    Pasternak, Iwona; Wesolowski, Marek; Jozwik, Iwona; Lukosius, Mindaugas; Lupina, Grzegorz; Dabrowski, Pawel; Baranowski, Jacek M; Strupinski, Wlodek

    2016-02-22

    The successful integration of graphene into microelectronic devices is strongly dependent on the availability of direct deposition processes, which can provide uniform, large area and high quality graphene on nonmetallic substrates. As of today the dominant technology is based on Si and obtaining graphene with Si is treated as the most advantageous solution. However, the formation of carbide during the growth process makes manufacturing graphene on Si wafers extremely challenging. To overcome these difficulties and reach the set goals, we proposed growth of high quality graphene layers by the CVD method on Ge(100)/Si(100) wafers. In addition, a stochastic model was applied in order to describe the graphene growth process on the Ge(100)/Si(100) substrate and to determine the direction of further processes. As a result, high quality graphene was grown, which was proved by Raman spectroscopy results, showing uniform monolayer films with FWHM of the 2D band of 32 cm(-1).

  20. Mobility-limiting mechanisms in single and dual channel strained Si/SiGe MOSFETs

    International Nuclear Information System (INIS)

    Olsen, S.H.; Dobrosz, P.; Escobedo-Cousin, E.; Bull, S.J.; O'Neill, A.G.

    2005-01-01

    Dual channel strained Si/SiGe CMOS architectures currently receive great attention due to maximum performance benefits being predicted for both n- and p-channel MOSFETs. Epitaxial growth of a compressively strained SiGe layer followed by tensile strained Si can create a high mobility buried hole channel and a high mobility surface electron channel on a single relaxed SiGe virtual substrate. However, dual channel n-MOSFETs fabricated using a high thermal budget exhibit compromised mobility enhancements compared with single channel devices, in which both electron and hole channels form in strained Si. This paper investigates the mobility-limiting mechanisms of dual channel structures. The first evidence of increased interface roughness due to the introduction of compressively strained SiGe below the tensile strained Si channel is presented. Interface corrugations degrade electron mobility in the strained Si. Roughness measurements have been carried out using AFM and TEM. Filtering AFM images allowed roughness at wavelengths pertinent to carrier transport to be studied and the results are in agreement with electrical data. Furthermore, the first comparison of strain measurements in the surface channels of single and dual channel architectures is presented. Raman spectroscopy has been used to study channel strain both before and after processing and indicates that there is no impact of the buried SiGe layer on surface macrostrain. The results provide further evidence that the improved performance of the single channel devices fabricated using a high thermal budget arises from improved surface roughness and reduced Ge diffusion into the Si channel

  1. Growth model and structure evolution of Ag layers deposited on Ge films.

    Science.gov (United States)

    Ciesielski, Arkadiusz; Skowronski, Lukasz; Górecka, Ewa; Kierdaszuk, Jakub; Szoplik, Tomasz

    2018-01-01

    We investigated the crystallinity and optical parameters of silver layers of 10-35 nm thickness as a function 2-10 nm thick Ge wetting films deposited on SiO 2 substrates. X-ray reflectometry (XRR) and X-ray diffraction (XRD) measurements proved that segregation of germanium into the surface of the silver film is a result of the gradient growth of silver crystals. The free energy of Ge atoms is reduced by their migration from boundaries of larger grains at the Ag/SiO 2 interface to boundaries of smaller grains near the Ag surface. Annealing at different temperatures and various durations allowed for a controlled distribution of crystal dimensions, thus influencing the segregation rate. Furthermore, using ellipsometric and optical transmission measurements we determined the time-dependent evolution of the film structure. If stored under ambient conditions for the first week after deposition, the changes in the transmission spectra are smaller than the measurement accuracy. Over the course of the following three weeks, the segregation-induced effects result in considerably modified transmission spectra. Two months after deposition, the slope of the silver layer density profile derived from the XRR spectra was found to be inverted due to the completed segregation process, and the optical transmission spectra increased uniformly due to the roughened surfaces, corrosion of silver and ongoing recrystallization. The Raman spectra of the Ge wetted Ag films were measured immediately after deposition and ten days later and demonstrated that the Ge atoms at the Ag grain boundaries form clusters of a few atoms where the Ge-Ge bonds are still present.

  2. Structure of Ag, Fe and Ge microclusters

    International Nuclear Information System (INIS)

    Montano, P.A.; Shenoy, G.K.; Schulze, W.

    1989-01-01

    The structures of Ag, Fe and Ge microclusters were determined using EXAFS. The measurements were performed over a wide range of clusters sizes. The clusters were prepared using the gas aggregation technique and isolated in solid argon at 4.2 K. The measurements were performed at the National Synchrotron Light Source (NSLS) at beam line X-18B. A strong contraction of the interatomic distances was observed for Ag dimers and multimers. Silver clusters larger than 12 A mean diameter show a small contraction of the nn distance and a structure consistent with an fcc lattice. By contrast clusters smaller than 12 A show the presence of a small expansion and a strong reduction or absence of nnn in the EXAFS signal. This points towards a different crystallographic structure for Ag microclusters with diameter less than 12 A. In iron clusters we observe a gradual reduction of the nn distance as the cluster size decreases. The interatomic distance for iron dimers was determined to be 1.94 A, in good agreement with earlier measurements. The iron microclusters show a bcc structure down to a mean diameter of 9 A. Iron clusters with 9 A mean diameter show a structure inconsistent with a bcc lattice. The new structure is consistent with an fcc or hcp lattice. The measurements on Ge clusters show the presence of only nearest neighbors. There was clear evidence of temporal annealing as determined by variations in the near edge structure of the K-absorption edge. Absorption edge measurements were also performed for free Ge clusters travelling perpendicular to the direction of the synchrotron radiation beam. The measurements performed on the free clusters were consistent with those obtained for matrix isolated clusters. (orig.)

  3. HPC4Energy Final Report : GE Energy

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Steven G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Van Zandt, Devin T. [GE Energy Consulting, Schenectady, NY (United States); Thomas, Brian [GE Energy Consulting, Schenectady, NY (United States); Mahmood, Sajjad [GE Energy Consulting, Schenectady, NY (United States); Woodward, Carol S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2014-02-25

    Power System planning tools are being used today to simulate systems that are far larger and more complex than just a few years ago. Advances in renewable technologies and more pervasive control technology are driving planning engineers to analyze an increasing number of scenarios and system models with much more detailed network representations. Although the speed of individual CPU’s has increased roughly according to Moore’s Law, the requirements for advanced models, increased system sizes, and larger sensitivities have outstripped CPU performance. This computational dilemma has reached a critical point and the industry needs to develop the technology to accurately model the power system of the future. The hpc4energy incubator program provided a unique opportunity to leverage the HPC resources available to LLNL and the power systems domain expertise of GE Energy to enhance the GE Concorda PSLF software. Well over 500 users worldwide, including all of the major California electric utilities, rely on Concorda PSLF software for their power flow and dynamics. This pilot project demonstrated that the GE Concorda PSLF software can perform contingency analysis in a massively parallel environment to significantly reduce the time to results. An analysis with 4,127 contingencies that would take 24 days on a single core was reduced to 24 minutes when run on 4,217 cores. A secondary goal of this project was to develop and test modeling techniques that will expand the computational capability of PSLF to efficiently deal with systems sizes greater than 150,000 buses. Toward this goal the matrix reordering implementation time was sped up 9.5 times by optimizing the code and introducing threading.

  4. Die Internen Und Externen Interferenzfehler Beim Lernprozess Des Deutschen Als Zweitfremdsprache Für Türkische Muttersprachler Und Vorschläge Zur Fehlertherapie Internal And External Interference Errors In The Process Of Learning German As A Second Foreign Language And Methods To Prevent Mistakes

    Directory of Open Access Journals (Sweden)

    Adnan OFLAZ

    2013-09-01

    Full Text Available Das Ziel dieser Untersuchung liegt darin, die verschiedenen Arten von Interferenzen, die beim Lernprozess der deutschen Sprache auftreten, zuerst theoretisch aufzuklären, dann systematisch mit der kontrastiven Methode durch eine Fehleranalyse zu bestimmen und danach auszuwerten. Die Beeinflussung der Sprache von einer anderen Sprache verursacht Überschneidungen. Interferenzfehler können wir in den Bereichen “Phonologie, Orthographie, Morphologie, Syntax, Semantik, Pragmatik oder auch Textlinguistik erkennen. Anschließend werden Vorschläge zur Fehlerkorrektur auf den grammatikalischen, ortographischen und lexikalischen Ebenen vorgenommen. Betrachtet man dies aus dem kognitiven Blickwinkel, kann jeder unschwer erkennen, dass die Vorkenntnisse retroaktive und proaktive Effekte haben. Das heißt, diese Kenntnisse können den Lernprozess entweder positiv oder negativ beeinträchtigen. Von diesem Ausgangspunkt aus werden in dieser Arbeit die Wechselwirkungen, die sowohl von der erstgelernten Fremdsprache als auch von der Muttersprache abhängig sind, der Reihe nach identifiziert, klassifiziert und abschliessend analysiert. Auf den Ergebnissen dieser Fehleranalyse basierend, machen Studenten unter dem Einfluss der interlingualen Interferenzen meist Fehler bei der Wortstellung, der Zeitform „Perfekt“, Pluralbildung, der Deklination der Adjektive, der Groß- bzw Kleinschreibung und bei dem Gebrauch der Konjunktionen sowie auf den lexikalischen Ebenen. Unter dem Einfluss der intralingualen Interferenzen machen sie Fehler bei der Bildung der Zeitformen „Perfekt und Präteritum“ und bei der Konjugation des Verbs. The primary aim of this study is to analyze the different types ofinterferences that may occur in the process of learning the Germanlanguage both theoretically and systematically by making use of thecontrastive method in order to detect and evaluate common errors. In asecond step, methods to correct these errors on a grammatical

  5. Radiation-modified structure of Ge25Sb15S60 and Ge35Sb5S60 glasses

    International Nuclear Information System (INIS)

    Kavetskyy, T.; Shpotyuk, O.; Kaban, I.; Hoyer, W.

    2008-01-01

    Atomic structures of Ge 25 Sb 15 S 60 and Ge 35 Sb 5 S 60 glasses are investigated in the γ-irradiated and annealed after γ-irradiation states by means of high-energy synchrotron x-ray diffraction technique. The first sharp diffraction peak (FSDP) is detected at around 1.1 A -1 in the structure factors of both alloys studied. The FSDP position is found to be stable for radiation/annealing treatment of the samples, while the FSDP intensity shows some changes between γ-irradiated and annealed states. The peaks in the pair distribution functions observed between 2 and 4 A are related to the Ge-S, Ge-Sb, and Sb-Sb first neighbor correlations and Ge-Ge second neighbor correlations in the edge-shared GeS 4/2 tetrahedra, and S-S and/or Ge-Ge second neighbor correlations in the corner-shared GeS 4/2 tetrahedra. Three mechanisms of the radiation-/annealing-induced changes are discussed in the framework of coordination topological defect formation and bond-free solid angle concepts

  6. Wozu Open-Access-Transformationsverträge?

    Directory of Open Access Journals (Sweden)

    Angela Holzer

    2017-07-01

    Full Text Available Die Deutsche Forschungsgemeinschaft (DFG hat im Frühjahr 2017 eine Ausschreibung veröffentlicht, um „Open-Access-Transformationsverträge“ zu unterstützen. Anträge können bis Ende 2018 gestellt werden. Dieser Artikel erläutert den Inhalt der Ausschreibung, erklärt die Beweggründe für die Ausschreibung, diskutiert die Vor- und Nachteile dieses Instruments der Open-Access-Transformation und legt dar, inwiefern einzelne Bibliotheken in Deutschland die Transformation befördern können.

  7. High spin spectroscopy of 70Ge

    International Nuclear Information System (INIS)

    Kumar Raju, M.; Sugathan, P.; Seshi Reddy, T.; Thirumala Rao, B.V.; Madhusudhana Rao, P.V.; Muralithar, S.; Singh, R.P.; Bhowmik, R.K.

    2011-01-01

    Structure of nuclei in mass 70 region is of interest due to presence of a variety of complex phenomenon. In these nuclei rapid change of nuclear shape with proton and neutron numbers, spin and excitation energy. Valance nucleons in f-p-g shell configuration will drive the nuclei towards high deformations. Relatively large values of quadrupole deformation are evident in the even-even nuclei in this region. Present study is aimed to explore the high spin structure of the 70 Ge nucleus. A negative parity structure was reported in an earlier study

  8. Axial Ge/Si nanowire heterostructure tunnel FETs

    Energy Technology Data Exchange (ETDEWEB)

    Picraux, Sanuel T [Los Alamos National Laboratory; Daych, Shadi A [Los Alamos National Laboratory

    2010-01-01

    The vapor-liquid-solid (VLS) growth of semiconductor nanowires allows doping and composition modulation along their axis and the realization of axial 1 D heterostructures. This provides additional flexibility in energy band-edge engineering along the transport direction which is difficult to attain by planar materials growth and processing techniques. We report here on the design, growth, fabrication, and characterization of asymmetric heterostructure tunnel field-effect transistors (HTFETs) based on 100% compositionally modulated Si/Ge axial NWs for high on-current operation and low ambipolar transport behavior. We discuss the optimization of band-offsets and Schottky barrier heights for high performance HTFETs and issues surrounding their experimental realization. Our HTFET devices with 10 nm PECVD SiN{sub x} gate dielectric resulted in a measured current drive exceeding 100 {mu}A/{mu}m (I/{pi}D) and 10{sup 5} I{sub on}/I{sub off} ratios.

  9. SiGe HBTs Optimization for Wireless Power Amplifier Applications

    Directory of Open Access Journals (Sweden)

    Pierre-Marie Mans

    2010-01-01

    Full Text Available This paper deals with SiGe HBTs optimization for power amplifier applications dedicated to wireless communications. In this work, we investigate the fT-BVCEO tradeoff by various collector optimization schemes such as epilayer thickness and dopant concentration, and SIC and CAP characteristics. Furthermore, a new trapezoidal base Germanium (Ge profile is proposed. Thanks to this profile, precise control of Ge content at the metallurgical emitter-base junction is obtained. Gain stability is obtained for a wide range of temperatures through tuning the emitter-base junction Ge percent. Finally, a comprehensive investigation of Ge introduction into the collector (backside Ge profile is conducted in order to improve the fT values at high injection levels.

  10. Fabrication of core-shell nanostructures via silicon on insulator dewetting and germanium condensation: towards a strain tuning method for SiGe-based heterostructures in a three-dimensional geometry.

    Science.gov (United States)

    Naffouti, Meher; David, Thomas; Benkouider, Abdelmalek; Favre, Luc; Cabie, Martiane; Ronda, Antoine; Berbezier, Isabelle; Abbarchi, Marco

    2016-07-29

    We report on a novel method for the implementation of core-shell SiGe-based nanocrystals combining silicon on insulator dewetting in a molecular beam epitaxy reactor with an ex situ Ge condensation process. With an in situ two-step process (annealing and Ge deposition) we produce two families of islands on the same sample: Si-rich, formed during the first step and, all around them, Ge-rich formed after Ge deposition. By increasing the amount of Ge deposited on the annealed samples from 0 to 18 monolayers, the islands' shape in the Si-rich zones can be tuned from elongated and flat to more symmetric and with a larger vertical aspect ratio. At the same time, the spatial extension of the Ge-rich zones is progressively increased as well as the Ge content in the islands. Further processing by ex situ rapid thermal oxidation results in the formation of a core-shell composition profile in both Si and Ge-rich zones with atomically sharp heterointerfaces. The Ge condensation induces a Ge enrichment of the islands' shell of up to 50% while keeping a pure Si core in the Si-rich zones and a ∼25% SiGe alloy in the Ge-rich ones. The large lattice mismatch between core and shell, the absence of dislocations and the islands' monocrystalline nature render this novel class of nanostructures a promising device platform for strain-based band-gap engineering. Finally, this method can be used for the implementation of ultralarge scale meta-surfaces with dielectric Mie resonators for light manipulation at the nanoscale.

  11. Pattern formation on Ge by low energy ion beam erosion

    International Nuclear Information System (INIS)

    Teichmann, Marc; Lorbeer, Jan; Frost, Frank; Rauschenbach, Bernd; Ziberi, Bashkim

    2013-01-01

    Modification of nanoscale surface topography is inherent to low-energy ion beam erosion processes and is one of the most important fields of nanotechnology. In this report a comprehensive study of surface smoothing and self-organized pattern formation on Ge(100) by using different noble gases ion beam erosion is presented. The investigations focus on low ion energies (⩽ 2000 eV) and include the entire range of ion incidence angles. It is found that for ions (Ne, Ar) with masses lower than the mass of the Ge target atoms, no pattern formation occurs and surface smoothing is observed for all angles of ion incidence. In contrast, for erosion with higher mass ions (Kr, Xe), ripple formation starts at incidence angles of about 65° depending on ion energy. At smaller incident angles surface smoothing occurs again. Investigations of the surface dynamics for specific ion incidence angles by changing the ion fluence over two orders of magnitude gives a clear evidence for coarsening and faceting of the surface pattern. Both observations indicate that gradient-dependent sputtering and reflection of primary ions play crucial role in the pattern evolution, just at the lowest accessible fluences. The results are discussed in relation to recently proposed redistributive or stress-induced models for pattern formation. In addition, it is argued that a large angular variation of the sputter yield and reflected primary ions can significantly contribute to pattern formation and evolution as nonlinear and non-local processes as supported by simulation of sputtering and ion reflection. (paper)

  12. Room-temperature ferromagnetic Cr-doped Ge/GeOx core–shell nanowires

    Science.gov (United States)

    Katkar, Amar S.; Gupta, Shobhnath P.; Motin Seikh, Md; Chen, Lih-Juann; Walke, Pravin S.

    2018-06-01

    The Cr-doped tunable thickness core–shell Ge/GeOx nanowires (NWs) were synthesized and characterized using x-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, energy-dispersive x-ray spectroscopy, x-ray photoelectron spectroscopy and magnetization studies. The shell thickness increases with the increase in synthesis temperature. The presence of metallic Cr and Cr3+ in core–shell structure was confirmed from XPS study. The magnetic property is highly sensitive to the core–shell thickness and intriguing room temperature ferromagnetism is realized only in core–shell NWs. The magnetization decreases with an increase in shell thickness and practically ceases to exist when there is no core. These NWs show remarkably high Curie temperature (TC > 300 K) with the dominating values of its magnetic remanence (MR) and coercivity (HC) compared to germanium dilute magnetic semiconductor nanomaterials. We believe that our finding on these Cr-doped Ge/GeOX core–shell NWs has the potential to be used as a hard magnet for future spintronic devices, owing to their higher characteristic values of ferromagnetic ordering.

  13. Optimal Ge/SiGe nanofin geometries for hole mobility enhancement: Technology limit from atomic simulations

    Science.gov (United States)

    Vedula, Ravi Pramod; Mehrotra, Saumitra; Kubis, Tillmann; Povolotskyi, Michael; Klimeck, Gerhard; Strachan, Alejandro

    2015-05-01

    We use first principles simulations to engineer Ge nanofins for maximum hole mobility by controlling strain tri-axially through nano-patterning. Large-scale molecular dynamics predict fully relaxed, atomic structures for experimentally achievable nanofins, and orthogonal tight binding is used to obtain the corresponding electronic structure. Hole transport properties are then obtained via a linearized Boltzmann formalism. This approach explicitly accounts for free surfaces and associated strain relaxation as well as strain gradients which are critical for quantitative predictions in nanoscale structures. We show that the transverse strain relaxation resulting from the reduction in the aspect ratio of the fins leads to a significant enhancement in phonon limited hole mobility (7× over unstrained, bulk Ge, and 3.5× over biaxially strained Ge). Maximum enhancement is achieved by reducing the width to be approximately 1.5 times the height and further reduction in width does not result in additional gains. These results indicate significant room for improvement over current-generation Ge nanofins, provide geometrical guidelines to design optimized geometries and insight into the physics behind the significant mobility enhancement.

  14. Optimal Ge/SiGe nanofin geometries for hole mobility enhancement: Technology limit from atomic simulations

    International Nuclear Information System (INIS)

    Vedula, Ravi Pramod; Mehrotra, Saumitra; Kubis, Tillmann; Povolotskyi, Michael; Klimeck, Gerhard; Strachan, Alejandro

    2015-01-01

    We use first principles simulations to engineer Ge nanofins for maximum hole mobility by controlling strain tri-axially through nano-patterning. Large-scale molecular dynamics predict fully relaxed, atomic structures for experimentally achievable nanofins, and orthogonal tight binding is used to obtain the corresponding electronic structure. Hole transport properties are then obtained via a linearized Boltzmann formalism. This approach explicitly accounts for free surfaces and associated strain relaxation as well as strain gradients which are critical for quantitative predictions in nanoscale structures. We show that the transverse strain relaxation resulting from the reduction in the aspect ratio of the fins leads to a significant enhancement in phonon limited hole mobility (7× over unstrained, bulk Ge, and 3.5× over biaxially strained Ge). Maximum enhancement is achieved by reducing the width to be approximately 1.5 times the height and further reduction in width does not result in additional gains. These results indicate significant room for improvement over current-generation Ge nanofins, provide geometrical guidelines to design optimized geometries and insight into the physics behind the significant mobility enhancement

  15. Optimal Ge/SiGe nanofin geometries for hole mobility enhancement: Technology limit from atomic simulations

    Energy Technology Data Exchange (ETDEWEB)

    Vedula, Ravi Pramod; Mehrotra, Saumitra; Kubis, Tillmann; Povolotskyi, Michael; Klimeck, Gerhard [School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47907 (United States); Strachan, Alejandro, E-mail: strachan@purdue.edu [School of Materials Engineering and Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907 (United States)

    2015-05-07

    We use first principles simulations to engineer Ge nanofins for maximum hole mobility by controlling strain tri-axially through nano-patterning. Large-scale molecular dynamics predict fully relaxed, atomic structures for experimentally achievable nanofins, and orthogonal tight binding is used to obtain the corresponding electronic structure. Hole transport properties are then obtained via a linearized Boltzmann formalism. This approach explicitly accounts for free surfaces and associated strain relaxation as well as strain gradients which are critical for quantitative predictions in nanoscale structures. We show that the transverse strain relaxation resulting from the reduction in the aspect ratio of the fins leads to a significant enhancement in phonon limited hole mobility (7× over unstrained, bulk Ge, and 3.5× over biaxially strained Ge). Maximum enhancement is achieved by reducing the width to be approximately 1.5 times the height and further reduction in width does not result in additional gains. These results indicate significant room for improvement over current-generation Ge nanofins, provide geometrical guidelines to design optimized geometries and insight into the physics behind the significant mobility enhancement.

  16. On the Potential Application of the Wrinkled SiGe/SiGe Nanofilms

    Czech Academy of Sciences Publication Activity Database

    Fedorchenko, Alexander I.; Cheng, H. H.; Wang, W.; Ch.

    2016-01-01

    Roč. 6, č. 2 (2016), s. 19-23 ISSN 2160-049X Institutional support: RVO:61388998 Keywords : wrinkled SiGe nanofilms * terahertz radiation * terahertz gap Subject RIV: BE - Theoretical Physics http://www.scirp.org/journal/wjm,http://dx.doi.org/10.4236/wjm.2016.62003

  17. Sample Scripts for Generating PaGE-OM XML [

    Lifescience Database Archive (English)

    Full Text Available Sample Scripts for Generating PaGE-OM XML This page is offering some sample scripts...on MySQL. Outline chart of procedure 6. Creating RDB tables for Generating PaGE-OM XML These scripts help yo...wnload: create_tables_sql2.zip 7. Generating PaGE-OM XML from phenotype data This sample Perl script helps y

  18. Innovative Ge Quantum Dot Functional Sensing and Metrology Devices

    Science.gov (United States)

    2017-08-21

    Sensing/Metrology Devices Period: May 26th 2015May 25th 2017 Investigators: Pei-Wen Li Affiliation: Department of Electrical Engineering , National...light sources as well as low-power, high-speed Ge photodetectors indeed requires the growth of direct-gap Ge, heterostructure engineering for...All these tasks cannot be simply conducted in terms of bulk Ge technology, and it is no doubt that nanoscience and nanotechnology would offer

  19. Electrical and magnetic transport properties of DyTiGe

    International Nuclear Information System (INIS)

    Dagula, W.; Tegus, O.; Li, X.W.; Zhang, L.; Brueck, E.; Boer, F.R. de; Buschow, K.H.J.

    2004-01-01

    Electrical resistivity and magnetoresistance of DyTiGe were investigated as a function of temperature and magnetic field. DyTiGe is an antiferromagnet with Neel temperature, T N , of 180 K. The electrical resistivity has an anomaly around T N . Below T N , the magnetoresistance of DyTiGe abruptly changes at a critical field. At 5 K, we observe a magnetoresistance reduction of about 20%

  20. New data on excited level scheme of 73Ge nucleus

    International Nuclear Information System (INIS)

    Kosyak, Yu.G.; Kaipov, D.K.; Chekushina, L.V.

    1990-01-01

    New data on the scheme of 73 Ge decay obtained by the method of reactor fast neutron inelastic scattering are presented. γ-Spectra from reaction 73 Ge(n, n'γ) 73 Ge at the angles of 90 and 124 deg of relatively incident neutron beam have been measured. Experimental populations of the levels are studied. 29 new γ-transitions have been identified, two new levels have been introduced

  1. Development of {sup 77}Ge/{sup 77}As parent-daughter system for periodic removal of {sup 77}As for environmental sanitation and biochemical purposes

    Energy Technology Data Exchange (ETDEWEB)

    Olah, Zita; Doczi, Rita [Budapest Univ. of Technology and Economics (Hungary). Inst. of Nuclear Techniques; Szuecs, Zoltan [Hungarian Academy of Sciences, Debrecen (Hungary). Inst. for Nuclear Research; Varga, Zoltan [Hungarian Academy of Sciences, Budapest (Hungary). Research Centre for Natural Sciences

    2015-07-01

    A simple method was developed for the separation of radioactive {sup 77}As from neutron irradiated natural GeO{sub 2} samples for environmental and biochemical studies. The method is based on the volatility of GeCl{sub 4}. The GeCl{sub 4} was co-evaporated from the reaction mixture with an azeotropic mixture of HCl and water, and immediately condensed into a separate finger part of the special glass apparatus which was cooled by liquid nitrogen. By inverting the room temperature and the deep frozen parts of the glass equipment after three half-lives of the {sup 77}Ge the separation process can be repetitive, getting a special type of {sup 77}Ge/{sup 77}As parent-daughter system. The radionuclidic purity of the remaining As fraction was found to be 99.95%. Its yield, however, drastically decreased in the second and subsequent separations.

  2. Development of 77Ge/77As parent-daughter system for periodic removal of 77As for environmental sanitation and biochemical purposes

    International Nuclear Information System (INIS)

    Olah, Zita; Doczi, Rita; Szuecs, Zoltan; Varga, Zoltan

    2015-01-01

    A simple method was developed for the separation of radioactive 77 As from neutron irradiated natural GeO 2 samples for environmental and biochemical studies. The method is based on the volatility of GeCl 4 . The GeCl 4 was co-evaporated from the reaction mixture with an azeotropic mixture of HCl and water, and immediately condensed into a separate finger part of the special glass apparatus which was cooled by liquid nitrogen. By inverting the room temperature and the deep frozen parts of the glass equipment after three half-lives of the 77 Ge the separation process can be repetitive, getting a special type of 77 Ge/ 77 As parent-daughter system. The radionuclidic purity of the remaining As fraction was found to be 99.95%. Its yield, however, drastically decreased in the second and subsequent separations.

  3. Interactions of hadrons in nuclear emulsion in the energy range 60 GeV - 400 GeV

    International Nuclear Information System (INIS)

    Holynski, R.

    1986-01-01

    Interactions of pions and protons in the energy range 60 GeV in nuclear emulsion have been analysed. The fragmentation process of the struck nucleus as well as the multiple production of relativistic particles have been investigated as a function of the primary energy and the effective thickness of the target. It is shown that both, the fragmentation of the target nucleus and particle production, can be described by models in which the projectile (or its constituents) undergoes multiple collisions inside the target nucleus. In particular the particle production in the projectile fragmentation region in pion-nucleus interactions is well described by the additive quark model. 47 refs., 35 figs., 2 tabs. (author)

  4. Electrical circuit model of ITO/AZO/Ge photodetector.

    Science.gov (United States)

    Patel, Malkeshkumar; Kim, Joondong

    2017-10-01

    In this data article, ITO/AZO/Ge photodetector was investigated for electrical circuit model. Due to the double (ITO and AZO) transparent metal-oxide films (DOI:10.1016/j.mssp.2016.03.007) (Yun et al., 2016) [1], the Ge heterojunction device has a better interface quality due to the AZO layer with a low electrical resistance due to the ITO layer (Yun et al., 2015) [2]. The electrical and interfacial benefitted ITO/AZO/Ge heterojunction shows the quality Schottky junction. In order to investigate the device, the ITO/AZO/Ge heterojunction was analyzed by R-C circuit model using the impedance spectroscopy.

  5. The first acceleration to 300 GeV

    CERN Multimedia

    CERN PhotoLab

    1976-01-01

    After the acceleration to 80 GeV in May the 200 GeV energy was attained on June 4, followed by a successful attempt to reach 300 GeV and then 400 GeV by the Council session on June 17. Here at the desk (centre) Boris Milman and Bas de Raad, (right) Pat Mills and a machine operator. Then standing on the back Jacques Althaber, Simon Van der Meer, Hans-Peter Kindermann, Raymond Rausch, John Adams, Klaus Batzner, and still back Antonio Millich, Jim Allaby, Wim Middelkoop, Bo Angerth, Hans Horisberger.

  6. Vertical Ge photodetector base on InP taper waveguide

    Science.gov (United States)

    Amiri, Iraj Sadegh; Ariannejad, M. M.; Azzuhri, S. R. B.; Anwar, T.; Kouhdaragh, V.; Yupapin, P.

    2018-06-01

    In this work, simulation is conducted to investigate Ge photodetectors monolithically integrated on Si chip. The performance of vertical Germanium photodetector with FDTD Solutions (optical simulation) and electrical simulation has been studied. Selective heteroepitaxy of Ge is functioned in the monolithic integration of Ge photodetectors. The potential of CMOS-compatible monolithic integration of Ge as photodetector is investigated and the performance optimization is presented. Additionally, the investigation is extended to electrical part, particularly in the conversion efficiency as well as operation under low supplied voltage condition.

  7. The Au modified Ge(1 1 0) surface

    Science.gov (United States)

    Zhang, L.; Kabanov, N. S.; Bampoulis, P.; Saletsky, A. M.; Zandvliet, H. J. W.; Klavsyuk, A. L.

    2018-05-01

    The pristine Ge(1 1 0) surface is composed of Ge pentagons, which are arranged in relatively large (16 × 2) and c(8 × 10) unit cells. The deposition of sub-monolayer amounts of Au and mild annealing results into de-reconstructed Ge(1 1 0) regions completely free of Ge pentagons and regions composed of nanowires that are aligned along the high symmetry [ 1 1 bar 0 ] direction of the Ge(1 1 0) surface. The de-reconstructed Ge(1 1 0) regions consist of atomic rows that are aligned along the [ 1 1 bar 0 ] direction. A substantial fraction of these substrate rows are straight and resemble the atom rows of the unreconstructed, i.e. bulk terminated, Ge(1 1 0) surface, whereas the other substrate rows have a meandering appearance. These meandering atom rows are comprised of two types of atoms, one type that appears dim, whereas the other type appears bright in filled-state scanning tunneling microscopy images. Using density functional theory calculations, we have tested more than 20 different atomic models for the meandering atom rows. The density functional theory calculations reveal that it is energetically favorable for the deposited Au atoms to exchange position with Ge atoms in the first layer. Based on these findings we conclude that the bright atoms are Ge atoms, whereas the dim atoms are Au atoms.

  8. Heteroepitaxial Ge-on-Si by DC magnetron sputtering

    Directory of Open Access Journals (Sweden)

    Martin Steglich

    2013-07-01

    Full Text Available The growth of Ge on Si(100 by DC Magnetron Sputtering at various temperatures is studied by Spectroscopic Ellipsometry and Transmission Electron Microscopy. Smooth heteroepitaxial Ge films are prepared at relatively low temperatures of 380°C. Typical Stransky-Krastanov growth is observed at 410°C. At lower temperatures (320°C, films are essentially amorphous with isolated nanocrystallites at the Si-Ge interface. A minor oxygen contamination at the interface, developing after ex-situ oxide removal, is not seen to hinder epitaxy. Compensation of dislocation-induced acceptors in Ge by sputtering from n-doped targets is proposed.

  9. A 100 GeV SLAC Linac

    International Nuclear Information System (INIS)

    Farkas, Zoltan D

    2002-01-01

    The SLAC beam energy can be increased from the current 50 GeV to 100 GeV, if we change the operating frequency from the present 2856 MHz to 11424 MHz, using technology developed for the NLC. We replace the power distribution system with a proposed NLC distribution system as shown in Fig. 1. The four 3 meter s-band 820 nS fill time accelerator sections are replaced by six 2 meter x-band 120 nS fill time sections. Thus the accelerator length per klystron retains the same length, 12 meters. The 4050 65MW-3.5(micro)S klystrons are replaced by 75MW-1.5(micro)S permanent magnet klystrons developed here and in Japan. The present input to the klystrons would be multiplied by a factor of 4 and possibly amplified. The SLED [1] cavities have to be replaced. The increase in beam voltage is due to the higher elastance to group velocity ratio, higher compression ratio and higher unloaded to external Q ratio of the new SLED cavities. The average power input is reduced because of the narrower klystron pulse width and because the klystron electro-magnets are replaced by permanent magnets

  10. Magnetic phase diagrams of UNiGe

    International Nuclear Information System (INIS)

    Nakotte, H.; Hagmusa, I.H.; Klaasse, J.C.P.; Hagmusa, I.H.; Klaasse, J.C.P.

    1997-01-01

    UNiGe undergoes two magnetic transitions in zero field. Here, the magnetic diagrams of UNiGe for B parallel b and B parallel c are reported. We performed temperatures scans of the magnetization in static magnetic fields up to 19.5T applied along the b and c axes. For both orientations 3 magnetic phases have been identified in the B-T diagrams. We confirmed the previously reported phase boundaries for B parallel c, and in addition we determined the location of the phase boundaries for B parallel b. We discuss a possible relationship of the two zero-field antiferromagnetic phases (commensurate: T<42K; incommensurate: 42K< T<50K) and the field-induced phase, which, at low temperatures, occurs between 18 and 25T or 4 and 10T for B parallel b or B parallel c, respectively. Finally, we discuss the field dependence of the electronic contribution γ to the specific heat for B parallel c up to 17.5T, and we find that its field dependence is similar to the one found in more itinerant uranium compounds

  11. Pulsed ion-beam assisted deposition of Ge nanocrystals on SiO2 for non-volatile memory device

    International Nuclear Information System (INIS)

    Stepina, N.P.; Dvurechenskii, A.V.; Armbrister, V.A.; Kirienko, V.V.; Novikov, P.L.; Kesler, V.G.; Gutakovskii, A.K.; Smagina, Z.V.; Spesivtzev, E.V.

    2008-01-01

    A floating gate memory structure, utilizing Ge nanocrystals (NCs) deposited on tunnel SiO 2 , have been fabricated using pulsed low energy ion-beam induced molecular-beam deposition (MBD) in ultra-high vacuum. The ion-beam action is shown to stimulate the nucleation of Ge NCs when being applied after thin Ge layer deposition. Growth conditions for independent change of NCs size and array density were established allowing to optimize the structure parameters required for memory device. Activation energy E = 0.25 eV was determined from the temperature dependence of NCs array density. Monte Carlo simulation has shown that the process, determining NCs array density, is the surface diffusion. Embedding of the crystalline Ge dots into silicon oxide was carried out by selective oxidation of Si(100)/SiO 2 /Ge(NCs)/poly-Si structure. MOS-capacitor obtained after oxidation showed a hysteresis in its C-V curves attributed to charge retention in the Ge dots

  12. Ge deposition on Si(1 0 0) in the conditions close to dynamic equilibrium between islands growth and their decay

    International Nuclear Information System (INIS)

    Shklyaev, A.A.; Budazhapova, A.E.

    2016-01-01

    Graphical abstract: - Highlights: • Solid source MBE is used for island growth by Ge deposition on Si(1 0 0) at 700–900 °C. • Islands acquire a monomodal size distribution at temperatures above 800 °C. • Islands form ordered arrays during Ge deposition at 900 °C. • Conditions close to dynamic equilibrium are realized for growth and decay of islands at 900 °C. • Shape of ordered islands is cone with shallow sidewalls. - Abstract: The formation of islands arrays during Ge deposition on Si(1 0 0) at high temperatures is studied using scanning tunneling and electron microscopies. It is found that the island size and shape distributions, which are known to be bimodal at growth temperatures below 700 °C, become monomodal at temperatures above 800 °C. The obtained data suggest that the processes such as island nucleation and Ostwald ripening become less significant in the surface morphology formation, giving the advantage to selective attachment of deposited Ge atoms to island sidewalls and spatially inhomogeneous Si-Ge intermixing, as the temperature increases. At 900 °C, the islands exhibit a tendency to form laterally ordered arrays when the growth conditions approach the dynamic equilibrium between the growth of islands and their decay by means of Si-Ge intermixing. The islands ordering is accompanied by their shape transformation into the cone with shallow sidewalls inclined from (1 0 0) by angles of around 10°.

  13. Multi-photon production in $e^{+}e^{-}$ collisions at $\\sqrt{s}$ = 189 GeV

    CERN Document Server

    Abbiendi, G.; Alexander, G.; Allison, John; Anderson, K.J.; Anderson, S.; Arcelli, S.; Asai, S.; Ashby, S.F.; Axen, D.; Azuelos, G.; Ball, A.H.; Barberio, E.; Barlow, Roger J.; Batley, J.R.; Baumann, S.; Bechtluft, J.; Behnke, T.; Bell, Kenneth Watson; Bella, G.; Bellerive, A.; Bentvelsen, S.; Bethke, S.; Betts, S.; Biebel, O.; Biguzzi, A.; Bloodworth, I.J.; Bock, P.; Bohme, J.; Boeriu, O.; Bonacorsi, D.; Boutemeur, M.; Braibant, S.; Bright-Thomas, P.; Brigliadori, L.; Brown, Robert M.; Burckhart, H.J.; Capiluppi, P.; Carnegie, R.K.; Carter, A.A.; Carter, J.R.; Chang, C.Y.; Charlton, David G.; Chrisman, D.; Ciocca, C.; Clarke, P.E.L.; Clay, E.; Cohen, I.; Conboy, J.E.; Cooke, O.C.; Couchman, J.; Couyoumtzelis, C.; Coxe, R.L.; Cuffiani, M.; Dado, S.; Dallavalle, G.Marco; Dallison, S.; Davis, R.; De Jong, S.; de Roeck, A.; Dervan, P.; Desch, K.; Dienes, B.; Dixit, M.S.; Donkers, M.; Dubbert, J.; Duchovni, E.; Duckeck, G.; Duerdoth, I.P.; Estabrooks, P.G.; Etzion, E.; Fabbri, F.; Fanfani, A.; Fanti, M.; Faust, A.A.; Feld, L.; Ferrari, P.; Fiedler, F.; Fierro, M.; Fleck, I.; Frey, A.; Furtjes, A.; Futyan, D.I.; Gagnon, P.; Gary, J.W.; Gaycken, G.; Geich-Gimbel, C.; Giacomelli, G.; Giacomelli, P.; Gibson, W.R.; Gingrich, D.M.; Glenzinski, D.; Goldberg, J.; Gorn, W.; Grandi, C.; Graham, K.; Gross, E.; Grunhaus, J.; Gruwe, M.; Hajdu, C.; Hanson, G.G.; Hansroul, M.; Hapke, M.; Harder, K.; Harel, A.; Hargrove, C.K.; Harin-Dirac, M.; Hauschild, M.; Hawkes, C.M.; Hawkings, R.; Hemingway, R.J.; Herten, G.; Heuer, R.D.; Hildreth, M.D.; Hill, J.C.; Hobson, P.R.; Hocker, James Andrew; Hoffman, Kara Dion; Homer, R.J.; Honma, A.K.; Horvath, D.; Hossain, K.R.; Howard, R.; Huntemeyer, P.; Igo-Kemenes, P.; Imrie, D.C.; Ishii, K.; Jacob, F.R.; Jawahery, A.; Jeremie, H.; Jimack, M.; Jones, C.R.; Jovanovic, P.; Junk, T.R.; Kanaya, N.; Kanzaki, J.; Karlen, D.; Kartvelishvili, V.; Kawagoe, K.; Kawamoto, T.; Kayal, P.I.; Keeler, R.K.; Kellogg, R.G.; Kennedy, B.W.; Kim, D.H.; Klier, A.; Kobayashi, T.; Kobel, M.; Kokott, T.P.; Kolrep, M.; Komamiya, S.; Kowalewski, Robert V.; Kress, T.; Krieger, P.; von Krogh, J.; Kuhl, T.; Kyberd, P.; Lafferty, G.D.; Landsman, H.; Lanske, D.; Lauber, J.; Lawson, I.; Layter, J.G.; Lellouch, D.; Letts, J.; Levinson, L.; Liebisch, R.; Lillich, J.; List, B.; Littlewood, C.; Lloyd, A.W.; Lloyd, S.L.; Loebinger, F.K.; Long, G.D.; Losty, M.J.; Lu, J.; Ludwig, J.; Lui, D.; Macchiolo, A.; Macpherson, A.; Mader, W.; Mannelli, M.; Marcellini, S.; Marchant, T.E.; Martin, A.J.; Martin, J.P.; Martinez, G.; Mashimo, T.; Mattig, Peter; McDonald, W.John; McKenna, J.; Mckigney, E.A.; McMahon, T.J.; McPherson, R.A.; Meijers, F.; Mendez-Lorenzo, P.; Merritt, F.S.; Mes, H.; Meyer, I.; Michelini, A.; Mihara, S.; Mikenberg, G.; Miller, D.J.; Mohr, W.; Montanari, A.; Mori, T.; Nagai, K.; Nakamura, I.; Neal, H.A.; Nisius, R.; O'Neale, S.W.; Oakham, F.G.; Odorici, F.; Ogren, H.O.; Okpara, A.; Oreglia, M.J.; Orito, S.; Pasztor, G.; Pater, J.R.; Patrick, G.N.; Patt, J.; Perez-Ochoa, R.; Petzold, S.; Pfeifenschneider, P.; Pilcher, J.E.; Pinfold, J.; Plane, David E.; Poffenberger, P.; Poli, B.; Polok, J.; Przybycien, M.; Quadt, A.; Rembser, C.; Rick, H.; Robertson, S.; Robins, S.A.; Rodning, N.; Roney, J.M.; Rosati, S.; Roscoe, K.; Rossi, A.M.; Rozen, Y.; Runge, K.; Runolfsson, O.; Rust, D.R.; Sachs, K.; Saeki, T.; Sahr, O.; Sang, W.M.; Sarkisian, E.K.G.; Sbarra, C.; Schaile, A.D.; Schaile, O.; Scharff-Hansen, P.; Schieck, J.; Schmitt, S.; Schoning, A.; Schroder, Matthias; Schumacher, M.; Schwick, C.; Scott, W.G.; Seuster, R.; Shears, T.G.; Shen, B.C.; Shepherd-Themistocleous, C.H.; Sherwood, P.; Siroli, G.P.; Skuja, A.; Smith, A.M.; Snow, G.A.; Sobie, R.; Soldner-Rembold, S.; Spagnolo, S.; Sproston, M.; Stahl, A.; Stephens, K.; Stoll, K.; Strom, David M.; Strohmer, R.; Surrow, B.; Talbot, S.D.; Taras, P.; Tarem, S.; Teuscher, R.; Thiergen, M.; Thomas, J.; Thomson, M.A.; Torrence, E.; Towers, S.; Trefzger, T.; Trigger, I.; Trocsanyi, Z.; Tsur, E.; Turner-Watson, M.F.; Ueda, I.; Van Kooten, Rick J.; Vannerem, P.; Verzocchi, M.; Voss, H.; Wackerle, F.; Wagner, A.; Waller, D.; Ward, C.P.; Ward, D.R.; Watkins, P.M.; Watson, A.T.; Watson, N.K.; Wells, P.S.; Wermes, N.; Wetterling, D.; White, J.S.; Wilson, G.W.; Wilson, J.A.; Wyatt, T.R.; Yamashita, S.; Zacek, V.; Zer-Zion, D.

    1999-01-01

    The process e+e- to 2 (or 3) gammas is studied using data recorded with the OPAL detector at LEP. The data sample taken at a centre-of-mass energy of 189 GeV corresponds to a total integrated luminosity of 178 pb-1. The measured cross-section agrees well with the expectation from QED. A fit to the angular distribution is used to obtain improved limits at 95% CL on the QED cut-off parameters: Lambda+ > 304 GeV and Lambda- > 295 GeV as well as a mass limit for an excited electron, Me* > 306 GeV assuming equal e*egamma and eegamma couplings. Graviton exchange in the context of theories with higher dimensions is excluded for scales G+ < 660 GeV and G- < 634 GeV. No evidence for resonance production is found in the invariant mass spectrum of photon pairs. Limits are obtained for the cross-section times branching ratio for a resonance decaying into two photons and produced in association with another photon.

  14. Search for Higgs bosons and new particles decaying into two photons at $\\sqrt{s}$ = 183 GeV

    CERN Document Server

    Ackerstaff, K; Allison, J; Altekamp, N; Anderson, K J; Anderson, S; Arcelli, S; Asai, S; Ashby, S F; Axen, D A; Azuelos, Georges; Ball, A H; Barberio, E; Barlow, R J; Bartoldus, R; Batley, J Richard; Baumann, S; Bechtluft, J; Behnke, T; Bell, K W; Bella, G; Bentvelsen, Stanislaus Cornelius Maria; Bethke, Siegfried; Betts, S; Biebel, O; Biguzzi, A; Bird, S D; Blobel, Volker; Bloodworth, Ian J; Bobinski, M; Bock, P; Böhme, J; Boutemeur, M; Braibant, S; Bright-Thomas, P G; Brown, R M; Burckhart, Helfried J; Burgard, C; Bürgin, R; Capiluppi, P; Carnegie, R K; Carter, A A; Carter, J R; Chang, C Y; Charlton, D G; Chrisman, D; Ciocca, C; Clarke, P E L; Clay, E; Cohen, I; Conboy, J E; Cooke, O C; Couyoumtzelis, C; Coxe, R L; Cuffiani, M; Dado, S; Dallavalle, G M; Davis, R; De Jong, S; del Pozo, L A; de Roeck, A; Desch, Klaus; Dienes, B; Dixit, M S; Doucet, M; Dubbert, J; Duchovni, E; Duckeck, G; Duerdoth, I P; Eatough, D; Estabrooks, P G; Etzion, E; Evans, H G; Fabbri, Franco Luigi; Fanfani, A; Fanti, M; Faust, A A; Fiedler, F; Fierro, M; Fischer, H M; Fleck, I; Folman, R; Fürtjes, A; Futyan, D I; Gagnon, P; Gary, J W; Gascon, J; Gascon-Shotkin, S M; Geich-Gimbel, C; Geralis, T; Giacomelli, G; Giacomelli, P; Gibson, V; Gibson, W R; Gingrich, D M; Glenzinski, D A; Goldberg, J; Gorn, W; Grandi, C; Gross, E; Grunhaus, Jacob; Gruwé, M; Hanson, G G; Hansroul, M; Hapke, M; Hargrove, C K; Hartmann, C; Hauschild, M; Hawkes, C M; Hawkings, R; Hemingway, Richard J; Herndon, M; Herten, G; Heuer, R D; Hildreth, M D; Hill, J C; Hillier, S J; Hobson, P R; Höcker, Andreas; Homer, R James; Honma, A K; Horváth, D; Hossain, K R; Howard, R; Hüntemeyer, P; Igo-Kemenes, P; Imrie, D C; Ishii, K; Jacob, F R; Jawahery, A; Jeremie, H; Jimack, Martin Paul; Joly, A; Jones, C R; Jovanovic, P; Junk, T R; Karlen, D A; Kartvelishvili, V G; Kawagoe, K; Kawamoto, T; Kayal, P I; Keeler, Richard K; Kellogg, R G; Kennedy, B W; Klier, A; Kluth, S; Kobayashi, T; Kobel, M; Koetke, D S; Kokott, T P; Kolrep, M; Komamiya, S; Kowalewski, R V; Kress, T; Krieger, P; Von Krogh, J; Kyberd, P; Lafferty, G D; Lanske, D; Lauber, J; Lautenschlager, S R; Lawson, I; Layter, J G; Lazic, D; Lee, A M; Lefebvre, E; Lellouch, Daniel; Letts, J; Levinson, L; Liebisch, R; List, B; Littlewood, C; Lloyd, A W; Lloyd, S L; Loebinger, F K; Long, G D; Losty, Michael J; Ludwig, J; Liu, D; Macchiolo, A; MacPherson, A L; Mannelli, M; Marcellini, S; Markopoulos, C; Martin, A J; Martin, J P; Martínez, G; Mashimo, T; Mättig, P; McDonald, W J; McKenna, J A; McKigney, E A; McMahon, T J; McPherson, R A; Meijers, F; Menke, S; Merritt, F S; Mes, H; Meyer, J; Michelini, Aldo; Mihara, S; Mikenberg, G; Miller, D J; Mir, R; Mohr, W; Montanari, A; Mori, T; Nagai, K; Nakamura, I; Neal, H A; Nellen, B; Nisius, R; O'Neale, S W; Oakham, F G; Odorici, F; Ögren, H O; Oreglia, M J; Orito, S; Pálinkás, J; Pásztor, G; Pater, J R; Patrick, G N; Patt, J; Pérez-Ochoa, R; Petzold, S; Pfeifenschneider, P; Pilcher, J E; Pinfold, James L; Plane, D E; Poffenberger, P R; Poli, B; Polok, J; Przybycien, M B; Rembser, C; Rick, Hartmut; Robertson, S; Robins, S A; Rodning, N L; Roney, J M; Roscoe, K; Rossi, A M; Rozen, Y; Runge, K; Runólfsson, O; Rust, D R; Sachs, K; Saeki, T; Sahr, O; Sang, W M; Sarkisyan-Grinbaum, E; Sbarra, C; Schaile, A D; Schaile, O; Scharf, F; Scharff-Hansen, P; Schieck, J; Schmitt, B; Schmitt, S; Schöning, A; Schörner-Sadenius, T; Schröder, M; Schumacher, M; Schwick, C; Scott, W G; Seuster, R; Shears, T G; Shen, B C; Shepherd-Themistocleous, C H; Sherwood, P; Siroli, G P; Sittler, A; Skuja, A; Smith, A M; Snow, G A; Sobie, Randall J; Söldner-Rembold, S; Sproston, M; Stahl, A; Stephens, K; Steuerer, J; Stoll, K; Strom, D; Ströhmer, R; Tafirout, R; Talbot, S D; Tanaka, S; Taras, P; Tarem, S; Teuscher, R; Thiergen, M; Thomson, M A; Von Törne, E; Torrence, E; Towers, S; Trigger, I; Trócsányi, Z L; Tsur, E; Turcot, A S; Turner-Watson, M F; Van Kooten, R; Vannerem, P; Verzocchi, M; Vikas, P; Voss, H; Wäckerle, F; Wagner, A; Ward, C P; Ward, D R; Watkins, P M; Watson, A T; Watson, N K; Wells, P S; Wermes, N; White, J S; Wilson, G W; Wilson, J A; Wyatt, T R; Yamashita, S; Yekutieli, G; Zacek, V; Zer-Zion, D

    1998-01-01

    A search for the resonant production of high mass photon pairs associated with a leptonic or hadronic system has been performed using a data sample of 57.7 pb-1 collected at an average center-of-mass energy of 182.6 GeV with the OPAL detector at LEP. No evidence for contributions from non-Standard Model physics processes was observed. The observed candidates are used to place limits on BR (H to gamma gamma) assuming a Standard Model production rate for Higgs boson masses up to 92 GeV, and on the production cross section for a scalar resonance decaying into di-photons up to a mass of 170 GeV. Upper limits on the product of cross section and branching ratios, sigma(e+e- to XY) * BR(X to gamma gamma) * BR(Y to f fbar) as low as 70fb are obtained over the M(X) range 10 - 170 GeV for the case where 10 90 GeV, independent of the nature of Y provided it decays to a fermion pair and has negligible width. Higgs scalars which couple only to gauge bosons at Standard Model strength are ruled out up to a mass of 90.0 GeV...

  15. Searches for charginos and neutralinos in $e^+ e^-$ collisions at $\\sqrt{s}$ = 161 and 172 GeV

    CERN Document Server

    Barate, R; Décamp, D; Ghez, P; Goy, C; Lees, J P; Lucotte, A; Minard, M N; Nief, J Y; Pietrzyk, B; Casado, M P; Chmeissani, M; Comas, P; Crespo, J M; Delfino, M C; Fernández, E; Fernández-Bosman, M; Garrido, L; Juste, A; Martínez, M; Merino, G; Miquel, R; Mir, L M; Padilla, C; Park, I C; Pascual, A; Perlas, J A; Riu, I; Sánchez, F; Colaleo, A; Creanza, D; De Palma, M; Gelao, G; Iaselli, Giuseppe; Maggi, G; Maggi, M; Marinelli, N; Nuzzo, S; Ranieri, A; Raso, G; Ruggieri, F; Selvaggi, G; Silvestris, L; Tempesta, P; Tricomi, A; Zito, G; Huang, X; Lin, J; Ouyang, Q; Wang, T; Xie, Y; Xu, R; Xue, S; Zhang, J; Zhang, L; Zhao, W; Abbaneo, D; Alemany, R; Bazarko, A O; Becker, U; Bright-Thomas, P G; Cattaneo, M; Cerutti, F; Dissertori, G; Drevermann, H; Forty, Roger W; Frank, M; Gianotti, F; Hagelberg, R; Hansen, J B; Harvey, J; Janot, P; Jost, B; Kneringer, E; Lehraus, Ivan; Mato, P; Minten, Adolf G; Moneta, L; Pacheco, A; Pusztaszeri, J F; Ranjard, F; Rizzo, G; Rolandi, Luigi; Rousseau, D; Schlatter, W D; Schmitt, M; Schneider, O; Tejessy, W; Teubert, F; Tomalin, I R; Wachsmuth, H W; Wagner, A; Ajaltouni, Ziad J; Barrès, A; Boyer, C; Falvard, A; Ferdi, C; Gay, P; Guicheney, C; Henrard, P; Jousset, J; Michel, B; Monteil, S; Montret, J C; Pallin, D; Perret, P; Podlyski, F; Proriol, J; Rosnet, P; Rossignol, J M; Fearnley, Tom; Hansen, J D; Hansen, J R; Hansen, P H; Nilsson, B S; Rensch, B; Wäänänen, A; Daskalakis, G; Kyriakis, A; Markou, C; Simopoulou, Errietta; Vayaki, Anna; Blondel, A; Brient, J C; Machefert, F P; Rougé, A; Rumpf, M; Valassi, Andrea; Videau, H L; Boccali, T; Focardi, E; Parrini, G; Zachariadou, K; Cavanaugh, R J; Corden, M; Georgiopoulos, C H; Hühn, T; Jaffe, D E; Antonelli, A; Bencivenni, G; Bologna, G; Bossi, F; Campana, P; Capon, G; Casper, David William; Chiarella, V; Felici, G; Laurelli, P; Mannocchi, G; Murtas, F; Murtas, G P; Passalacqua, L; Pepé-Altarelli, M; Curtis, L; Dorris, S J; Halley, A W; Knowles, I G; Lynch, J G; O'Shea, V; Raine, C; Scarr, J M; Smith, K; Teixeira-Dias, P; Thompson, A S; Thomson, E; Thomson, F; Turnbull, R M; Buchmüller, O L; Dhamotharan, S; Geweniger, C; Graefe, G; Hanke, P; Hansper, G; Hepp, V; Kluge, E E; Putzer, A; Sommer, J; Tittel, K; Werner, S; Wunsch, M; Beuselinck, R; Binnie, David M; Cameron, W; Dornan, Peter J; Girone, M; Goodsir, S M; Martin, E B; Morawitz, P; Moutoussi, A; Nash, J; Sedgbeer, J K; Spagnolo, P; Stacey, A M; Williams, M D; Ghete, V M; Girtler, P; Kuhn, D; Rudolph, G; Betteridge, A P; Bowdery, C K; Buck, P G; Colrain, P; Crawford, G; Finch, A J; Foster, F; Hughes, G; Jones, R W L; Sloan, Terence; Whelan, E P; Williams, M I; Giehl, I; Hoffmann, C; Jakobs, K; Kleinknecht, K; Quast, G; Renk, B; Rohne, E; Sander, H G; Van Gemmeren, P; Zeitnitz, C; Aubert, Jean-Jacques; Benchouk, C; Bonissent, A; Bujosa, G; Carr, J; Coyle, P; Diaconu, C A; Ealet, A; Fouchez, D; Konstantinidis, N P; Leroy, O; Motsch, F; Payre, P; Talby, M; Sadouki, A; Thulasidas, M; Tilquin, A; Trabelsi, K; Aleppo, M; Antonelli, M; Ragusa, F; Berlich, R; Blum, Walter; Büscher, V; Dietl, H; Ganis, G; Gotzhein, C; Kroha, H; Lütjens, G; Lutz, Gerhard; Männer, W; Moser, H G; Richter, R H; Rosado-Schlosser, A; Schael, S; Settles, Ronald; Seywerd, H C J; Saint-Denis, R; Stenzel, H; Wiedenmann, W; Wolf, G; Boucrot, J; Callot, O; Chen, S; Davier, M; Duflot, L; Grivaz, J F; Heusse, P; Höcker, A; Jacholkowska, A; Kim, D W; Le Diberder, F R; Lefrançois, J; Lutz, A M; Marumi, M; Schune, M H; Serin, L; Tournefier, E; Veillet, J J; Videau, I; Zerwas, D; Azzurri, P; Bagliesi, G; Bettarini, S; Bozzi, C; Calderini, G; Ciulli, V; Dell'Orso, R; Fantechi, R; Ferrante, I; Giassi, A; Gregorio, A; Ligabue, F; Lusiani, A; Marrocchesi, P S; Messineo, A; Palla, Fabrizio; Sanguinetti, G; Sciabà, A; Sguazzoni, G; Steinberger, Jack; Tenchini, Roberto; Vannini, C; Venturi, A; Verdini, P G; Blair, G A; Bryant, L M; Chambers, J T; Green, M G; Medcalf, T; Perrodo, P; Strong, J A; Von Wimmersperg-Töller, J H; Botterill, David R; Clifft, R W; Edgecock, T R; Haywood, S; Maley, P; Norton, P R; Thompson, J C; Wright, A E; Bloch-Devaux, B; Colas, P; Fabbro, B; Lançon, E; Lemaire, M C; Locci, E; Pérez, P; Rander, J; Renardy, J F; Rosowsky, A; Roussarie, A; Schwindling, J; Trabelsi, A; Vallage, B; Black, S N; Dann, J H; Kim, H Y; Litke, A M; McNeil, M A; Taylor, G; Booth, C N; Brew, C A J; Cartwright, S L; Combley, F; Kelly, M S; Lehto, M H; Reeve, J; Thompson, L F; Affholderbach, K; Böhrer, A; Brandt, S; Cowan, G D; Foss, J; Grupen, Claus; Smolik, L; Stephan, F; Apollonio, M; Bosisio, L; Della Marina, R; Giannini, G; Gobbo, B; Musolino, G; Pütz, J; Rothberg, J E; Wasserbaech, S R; Williams, R W; Armstrong, S R; Charles, E; Elmer, P; Ferguson, D P S; Gao, Y; González, S; Greening, T C; Hayes, O J; Hu, H; Jin, S; McNamara, P A; Nachtman, J M; Nielsen, J; Orejudos, W; Pan, Y B; Saadi, Y; Scott, I J; Walsh, J; Wu Sau Lan; Wu, X; Yamartino, J M; Zobernig, G

    1998-01-01

    The data recorded by the ALEPH detector at centre-of-mass energies of 161, 170, and 172 GeV are analysed for signals of chargino and neutralino production. No evidence of a signal is found, although candidate events consistent with the expectations from Standard Model processes are observed. Limits at 95% C.L. on the production cross sections are derived and bounds on the parameters of the Minimal Supersymmetric Standard Model are set. The lower limit on the mass of the lightest chargino is 85.5 GeV/c^2 for gaugino-like charginos (mu = -500 GeV/c^2), and 85.0 GeV/c^2 for Higgsino-like charginos (M_2 = 500 GeV/c^2), for heavy sneutrinos (M(snu) > 200 GeV/c^2) and tanb = sqrt(2). The effect of light sleptons on chargino and neutralino limits is investigated. The assumptions of a universal slepton mass and a universal gaugino mass are relaxed, allowing less model-dependent limits to be obtained.

  16. Reduction in the formation temperature of Poly-SiGe alloy thin film in Si/Ge system

    Science.gov (United States)

    Tah, Twisha; Singh, Ch. Kishan; Madapu, K. K.; Sarguna, R. M.; Magudapathy, P.; Ilango, S.

    2018-04-01

    The role of deposition temperature in the formation of poly-SiGe alloy thin film in Si/Ge system is reported. For the set ofsamples deposited without any intentional heating, initiation of alloying starts upon post annealingat ˜ 500 °C leading to the formation of a-SiGe. Subsequently, poly-SiGe alloy phase could formonly at temperature ≥ 800 °C. Whereas, for the set of samples deposited at 500 °C, in-situ formation of poly-SiGe alloy thin film could be observed. The energetics of the incoming evaporated atoms and theirsubsequent diffusionsin the presence of the supplied thermal energy is discussed to understand possible reasons for lowering of formation temperature/energyof the poly-SiGe phase.

  17. In-situ Ga doping of fully strained Ge1-xSnx heteroepitaxial layers grown on Ge(001) substrates

    DEFF Research Database (Denmark)

    Shimura, Y.; Takeuchi, S.; Nakatsuka, O.

    2012-01-01

    to the introduction of dislocations, due to the increase in the strain of the Ge1-xSnx layers. We achieved the growth of a fully strained Ge0.922Sn0.078 layer on Ge with a Ga concentration of 5.5×1019 /cm3 without any dislocations and stacking faults. The resistivity of the Ga-doped Ge1-xSnx layer decreased as the Sn...... content was increased. This decrease was due to an increase in the carrier concentration, with an increase in the activation level of Ga atoms in the Ge1-xSnx epitaxial layers being induced by the introduction of Sn. As a result, we found that the resistivity for the Ge0.950Sn0.050 layer annealed at 600°C...

  18. Study of dimuon pair production in e+ e- collisions from 196 - 202 GeV

    CERN Document Server

    Flacher, Henning

    2000-01-01

    In this thesis the electroweak process $e^{+} e^{-}$ --> $μ^{+} μ^{-}$ was studied and an inclusive and exclusive cross section were measured. Furthermore the forward-backward asymmetry Afb was determined from the exclusive event sample. The investigated data was recorded·with the detector ALEPH at centre-of-mass energies of 196, 200 and 202 GeV resulting in a total integrated luminosity of 208.1 pb-1. All the measured results are in good agreement with the Standard Model. From the measurements of total cross sections and angular distributions for all the two fermion processes at energies from 130 - 202 GeV limits on processes beyond the Standard Model were derived. For Contact Interactions they were found to be of the order of 10 TeV while for TeV-Scale Quantum Gravity a limit for the ultra-violet cut-off parameter of A::1 TeV could be derived.

  19. Remote plasma enhanced chemical deposition of non-crystalline GeO2 on Ge and Si substrates.

    Science.gov (United States)

    Lucovsky, Gerald; Zeller, Daniel

    2011-09-01

    Non-crystalline GeO2 films remote were plasma deposited at 300 degrees C onto Ge substrates after a final rinse in NH4OH. The reactant precursors gas were: (i) down-stream injected 2% GeH4 in He as the Ge precursor, and (ii) up-stream, plasma excited O2-He mixtures as the O precursor. Films annealed at 400 degrees C displayed no evidence for loss of O resulting in Ge sub-oxide formation, and for a 5-6 eV mid-gap absorption associated with formation of GeOx suboxide bonding, x deposited on Ge and annealed at 600 degrees C and 700 degrees C display spectra indicative of loss of O-atoms, accompanied with a 5.5 eV absorption. X-ray absorption spectroscopy and many-electron theory are combined to describe symmetries and degeneracies for O-vacancy bonding defects. These include comparisons with remote plasma-deposited non-crystalline SiO2 on Si substrates with SiON interfacial layers. Three different properties of remote plasma GeO2 films are addressed comparisons between (i) conduction band and band edge states of GeO2 and SiO2, and (ii) electronic structure of O-atom vacancy defects in GeO2 and SiO2, and differences between (iii) annealing of GeO2 films on Ge substrates, and Si substrates passivated with SiON interfacial transition regions important for device applications.

  20. Inelastic anti pp interactions at 22.4 GeV/c compared with e+e- annihilation into hadrons

    International Nuclear Information System (INIS)

    Boos, E.G.; Ermilova, D.I.; Samoilov, V.V.; Temiraliev, T.

    1982-01-01

    The 22.4 GeV/c anti pp interactions with the leading particle and the slow proton subtracted are used as data on soft processes. Considerable similarity between them and hard processes, such as e + e - annihilation into hardrons, is found by means of studying charged multiplicities. KNO scaling and longitudinal as well as transverse spectra. (orig.)

  1. Magnetic and electrical properties of epitaxial GeMn

    Energy Technology Data Exchange (ETDEWEB)

    Ahlers, Stefan

    2009-01-15

    In this work, GeMn magnetic semiconductors will be investigated. The fabrication of GeMn thin films with Mn contents up to 11.7% was realised with molecular beam epitaxy. At a fabrication temperature of 60 C, the suppression of Mn{sub x}Ge{sub y} phases could reproducibly be obtained. Dislocation free epitaxy of diamond-lattice type GeMn thin films was observed. In all fabrication conditions where Mn{sub x}Ge{sub y} suppression was feasible, an inhomogeneous dispersion of Mn was observed in form of a self-assembly of nanometre sized, Mn rich regions in a Ge rich matrix. Each Mn rich region exhibits ferromagnetic coupling with high Curie temperatures exceeding, in part, room temperature. The local ferromagnetic ordering leads to the formation of large, spatially separated magnetic moments, which induce a superparamagnetic behaviour of the GeMn thin films. At low temperatures {<=} 20 K, remanent behaviour was found to emerge. X-ray absorption experiments revealed a similarity of the Mn incorporation in diamond-lattice type GeMn thin films and in the hexagonal lattice of the intermetallic Mn{sub 5}Ge{sub 3} phase, respectively. These tetrahedra represent building blocks of the Mn{sub 5}Ge{sub 3} unit cell. The incorporation of Mn{sub 5}Ge{sub 3} building blocks was found to be accompanied by local structural disorder. The electrical properties of GeMn thin films were addressed by transport measurements. It was shown that by using a n-type Ge substrate, a pn energy barrier between epilayers and substrate to suppress parallel substrate conduction paths can be introduced. With the pn barrier concept, first results on the magnetotransport behaviour of GeMn thin films were obtained. GeMn was found to be p-type, but of high resistivity. a series of GeMn thin films was fabricated, where intermetallic Mn{sub x}Ge{sub y} phase separation was supported in a controlled manner. Phase separation was found to result in the formation of partially coherent, nanometre sized Mn{sub 5

  2. Growth of two-dimensional Ge crystal by annealing of heteroepitaxial Ag/Ge(111) under N2 ambient

    Science.gov (United States)

    Ito, Koichi; Ohta, Akio; Kurosawa, Masashi; Araidai, Masaaki; Ikeda, Mitsuhisa; Makihara, Katsunori; Miyazaki, Seiichi

    2018-06-01

    The growth of a two-dimensional crystal of Ge atoms on an atomically flat Ag(111) surface has been demonstrated by the thermal annealing of a heteroepitaxial Ag/Ge structure in N2 ambient at atmospheric pressure. The surface morphology and chemical bonding features of heteroepitaxial Ag(111) grown on wet-cleaned Ge(111) after annealing at different temperatures and for various times have been systematically investigated to control the surface segregation of Ge atoms and the planarization of the heteroepitaxial Ag(111) surface.

  3. Oxidation kinetics of Si and SiGe by dry rapid thermal oxidation, in-situ steam generation oxidation and dry furnace oxidation

    Science.gov (United States)

    Rozé, Fabien; Gourhant, Olivier; Blanquet, Elisabeth; Bertin, François; Juhel, Marc; Abbate, Francesco; Pribat, Clément; Duru, Romain

    2017-06-01

    The fabrication of ultrathin compressively strained SiGe-On-Insulator layers by the condensation technique is likely a key milestone towards low-power and high performances FD-SOI logic devices. However, the SiGe condensation technique still requires challenges to be solved for an optimized use in an industrial environment. SiGe oxidation kinetics, upon which the condensation technique is founded, has still not reached a consensus in spite of various studies which gave insights into the matter. This paper aims to bridge the gaps between these studies by covering various oxidation processes relevant to today's technological needs with a new and quantitative analysis methodology. We thus address oxidation kinetics of SiGe with three Ge concentrations (0%, 10%, and 30%) by means of dry rapid thermal oxidation, in-situ steam generation oxidation, and dry furnace oxidation. Oxide thicknesses in the 50 Å to 150 Å range grown with oxidation temperatures between 850 and 1100 °C were targeted. The present work shows first that for all investigated processes, oxidation follows a parabolic regime even for thin oxides, which indicates a diffusion-limited oxidation regime. We also observe that, for all investigated processes, the SiGe oxidation rate is systematically higher than that of Si. The amplitude of the variation of oxidation kinetics of SiGe with respect to Si is found to be strongly dependent on the process type. Second, a new quantitative analysis methodology of oxidation kinetics is introduced. This methodology allows us to highlight the dependence of oxidation kinetics on the Ge concentration at the oxidation interface, which is modulated by the pile-up mechanism. Our results show that the oxidation rate increases with the Ge concentration at the oxidation interface.

  4. Structure and superconducting properties of Nb3Ge prepared in a UHV system

    International Nuclear Information System (INIS)

    Habermeier, H.U.; Stuttgart Univ.

    1981-01-01

    Nb 3 Ge films are prepared by coevaporation of Nb and Ge under well defined and controlled conditions. The formation of the A15 Nb 3 Ge phase is studied by varying the processing parameters - composition, deposition temperature, and impurity gas background - systematically. Single phase samples with Tsub(c) onsets as high as 21.5 K and lattice parameters of 0.5148 nm only be obtained in an environment with no added impurities and a Ge concentration of 23.8 at%. Oxygen as impurity gas enhances Tsub(c) slightly in samples of the optimal composition, whereas hydrogen as impurity gas does not affect the formation and the Tsub(c) of the A15 phase at all. The structure, (lattice parameters, grain sizes, and phases present) and the superconducting properties (Tsub(c), Hsub(c2)(0)) of the samples show a systematic correlation of the preparation parameters and the physical properties. The experimental results are explained qualitatively within the frame of the linear chain model of A15 superconductors combined with the introduction of anti-site defects. (author)

  5. Single photon detection in a waveguide-coupled Ge-on-Si lateral avalanche photodiode.

    Science.gov (United States)

    Martinez, Nicholas J D; Gehl, Michael; Derose, Christopher T; Starbuck, Andrew L; Pomerene, Andrew T; Lentine, Anthony L; Trotter, Douglas C; Davids, Paul S

    2017-07-10

    We examine gated-Geiger mode operation of an integrated waveguide-coupled Ge-on-Si lateral avalanche photodiode (APD) and demonstrate single photon detection at low dark count for this mode of operation. Our integrated waveguide-coupled APD is fabricated using a selective epitaxial Ge-on-Si growth process resulting in a separate absorption and charge multiplication (SACM) design compatible with our silicon photonics platform. Single photon detection efficiency and dark count rate is measured as a function of temperature in order to understand and optimize performance characteristics in this device. We report single photon detection of 5.27% at 1310 nm and a dark count rate of 534 kHz at 80 K for a Ge-on-Si single photon avalanche diode. Dark count rate is the lowest for a Ge-on-Si single photon detector in this range of temperatures while maintaining competitive detection efficiency. A jitter of 105 ps was measured for this device.

  6. Probing GeV-scale MSSM neutralino dark matter in collider and direct detection experiments

    Science.gov (United States)

    Duan, Guang Hua; Wang, Wenyu; Wu, Lei; Yang, Jin Min; Zhao, Jun

    2018-03-01

    Given the recent constraints from the dark matter (DM) direct detections, we examine a light GeV-scale (2-30 GeV) neutralino DM in the alignment limit of the Minimal Supersymmetric Standard Model (MSSM). In this limit without decoupling, the heavy CP-even scalar H plays the role of the Standard Model (SM) Higgs boson while the other scalar h can be rather light so that the DM can annihilate through the h resonance or into a pair of h to achieve the observed relic density. With the current collider and cosmological constraints, we find that such a light neutralino DM above 6 GeV can be excluded by the XENON-1T (2017) limits while the survivied parameter space below 6 GeV can be fully tested by the future germanium-based light dark matter detections (such as CDEX), by the Higgs coupling precison measurements or by the production process e+e- → hA at an electron-positron collider (Higgs factory).

  7. Difference gel electrophoresis (DiGE) identifies differentially expressed proteins in endoscopically-collected pancreatic fluid

    Science.gov (United States)

    Paulo, Joao A.; Lee, Linda S.; Banks, Peter A.; Steen, Hanno; Conwell, Darwin L.

    2012-01-01

    Alterations in the pancreatic fluid proteome of individuals with chronic pancreatitis may offer insights into the development and progression of the disease. The endoscopic pancreas function test (ePFT) can safely collect large volumes of pancreatic fluid that are potentially amenable to proteomic analyses using difference gel electrophoresis (DiGE) coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS). Pancreatic fluid was collected endoscopically using the ePFT method following secretin stimulation from three individuals with severe chronic pancreatitis and three chronic abdominal pain controls. The fluid was processed to minimize protein degradation and the protein profiles of each cohort, as determined by DiGE and LC-MS/MS, were compared. This DiGE-LC-MS/MS analysis reveals proteins that are differentially expressed in chronic pancreatitis compared to chronic abdominal pain controls. Proteins with higher abundance in pancreatic fluid from chronic pancreatitis individuals include: actin, desmoplankin, alpha-1-antitrypsin, SNC73, and serotransferrin. Those of relatively lower abundance include carboxypeptidase B, lipase, alpha-1-antichymotrypsin, alpha-2-macroglobulin, Arp2/3 subunit 4, glyceraldehyde-3-phosphate dehydrogenase, and protein disulfide isomerase. Endoscopic collection (ePFT) in tandem with DiGE-LC-MS/MS is a suitable approach for pancreatic fluid proteome analysis, however, further optimization of our protocol, as outlined herein, may improve proteome coverage in future analyses. PMID:21792986

  8. Characterization of Ge Nano structures Embedded Inside Porous Silicon for Photonics Application

    International Nuclear Information System (INIS)

    Rahim, A.F.A.; Hashim, M.R.; Rahim, A.F.A.; Ali, N.K.

    2011-01-01

    In this work we prepared germanium nano structures by means of filling the material inside porous silicon (PS) using conventional and cost effective technique, thermal evaporator. The PS acts as patterned substrate. It was prepared by anodization of silicon wafer in ethanoic hydrofluoric acid (HF). A Ge layer was then deposited onto the PS by thermal evaporation. This was followed by deposition of Si layer by thermal evaporation and anneal at 650 degree Celsius for 30 min. The process was completed by Ni metal deposition using thermal evaporator followed by metal annealing of 400 degree Celsius for 10 min to form metal semiconductor metal (MSM) photodetector. Structural analysis of the samples was performed using energy dispersive x-ray analysis (EDX), scanning electron microscope (SEM), X-ray diffraction (XRD) and Raman spectroscopy (RS). EDX spectrum suggests the presence of Ge inside the pores structure. Raman spectrum showed that good crystalline structure of Ge can be produced inside silicon pores with a phase with the diamond structure by (111), (220) and (400) reflections. Finally current-voltage (I-V) measurement of the MSM photodetector was carried out and showed lower dark currents compared to that of Si control device. Interestingly the device showed enhanced current gain compared to Si device which can be associated with the presence of Ge nano structures in the porous silicon. (author)

  9. Response function of semiconductor detectors, Ge and Si(Li)

    International Nuclear Information System (INIS)

    Zevallos Chavez, Juan Yury

    2003-01-01

    The Response Function (RF) for Ge and Si(Li) semiconductor detectors was obtained. The RF was calculated for five detectors, four Hp Ge with active volumes of 89 cm 3 , 50 cm 3 , 8 cm 3 and 5 cm 3 , and one Si(Li) with 0.143 cm 3 of active volume. The interval of energy studied ranged from 6 keV up to 1.5 MeV. Two kinds of studies were done in this work. The first one was the RF dependence with the detection geometry. Here the calculation of the RF for a geometry named as simple and an extrapolation of that RF, were both done. The extrapolation process analyzed both, spectra obtained with a shielding geometry and spectra where the source-detector distance was modified. The second one was the RF dependence with the detection electronics. This study was done varying the shaping time of the pulse in the detection electronics. The purpose was to verify the effect of the ballistic deficit in the resolution of the detector. This effect was not observed. The RF components that describe the region of the total absorption of the energy of the incident photons, and the partial absorption of this energy, were both treated. In particular, empirical functions were proposed for the treatment of both, the multiple scattering originated in the detector (crystal), and the photon scattering originated in materials of the neighborhood of the crystal. Another study involving Monte Carlo simulations was also done in order to comprehend the photon scattering structures produced in an iron shield. A deconvolution method is suggested, for spectra related to scattered radiation in order to assess the dose delivered to the scatterer. (author)

  10. Improvement of photoluminescence from Ge layer with patterned Si{sub 3}N{sub 4} stressors

    Energy Technology Data Exchange (ETDEWEB)

    Oda, Katsuya, E-mail: Katsuya.Oda.cb@hitachi.com; Okumura, Tadashi; Tani, Kazuki; Saito, Shin-ichi; Ido, Tatemi

    2014-04-30

    Lattice strain applied by patterned Si{sub 3}N{sub 4} stressors in order to improve the optical properties of Ge layers directly grown on a Si substrate was investigated. Patterned Si{sub 3}N{sub 4} stressors were fabricated by various methods and their effects on the strain and photoluminescence were studied. Although we found that when the stressor was fabricated by thermal chemical vapor deposition (CVD), the Ge waveguide was tensilely and compressively strained in the edge and center positions, respectively, and photoluminescence (PL) could be improved by decreasing the width of the waveguide, the crystallinity of the Ge waveguide was degraded by the thermal impact of the deposition process. Low-temperature methods were therefore used to make the patterned stressors. The tensile strain of the Ge layer increased from 0.14% to 0.2% when the stressor was grown by plasma enhanced CVD at 350 °C, but the effects of the increased tensile strain could not be confirmed because the Si{sub 3}N{sub 4} layer was unstable when irradiated with the excitation light used in photoluminescence measurements. Si{sub 3}N{sub 4} stressors grown by inductively coupled plasma CVD at room temperature increased the tensile strain of the Ge layer up to 0.4%, thus red-shifting the PL peak and obviously increasing the PL intensity. These results indicate that the Si{sub 3}N{sub 4} stressors fabricated by the room-temperature process efficiently improve the performance of Ge light-emitting devices. - Highlights: • Ge layers were directly grown on a Si substrate by low-temperature epitaxial growth. • Si{sub 3}N{sub 4} stressors were fabricated on the Ge layers by various methods. • Tensile strain of the Ge layers was improved by the Si{sub 3}N{sub 4} stressors. • Photoluminescence (PL) intensity was increased with the Si{sub 3}N{sub 4} stressors. • Red-shift of the PL spectra was observed from the tensile strained Ge layers.

  11. Shell model description of Ge isotopes

    International Nuclear Information System (INIS)

    Hirsch, J G; Srivastava, P C

    2012-01-01

    A shell model study of the low energy region of the spectra in Ge isotopes for 38 ≤ N ≤ 50 is presented, analyzing the excitation energies, quadrupole moments, B(E2) values and occupation numbers. The theoretical results have been compared with the available experimental data. The shell model calculations have been performed employing three different effective interactions and valence spaces. We have used two effective shell model interactions, JUN45 and jj44b, for the valence space f 5/2 pg 9/2 without truncation. To include the proton subshell f 7/2 in valence space we have employed the fpg effective interaction due to Sorlin et al., with 48 Ca as a core and a truncation in the number of excited particles.

  12. 3 GeV Injector Design Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Wiedemann, H.; /SLAC, SSRL

    2009-12-16

    This Design Handbook is intended to be the main reference book for the specifications of the 3 GeV SPEAR booster synchrotron project. It is intended to be a consistent description of the project including design criteria, key technical specifications as well as current design approaches. Since a project is not complete till it's complete changes and modifications of early conceptual designs must be expected during the duration of the construction. Therefore, this Design Handbook is issued as a loose leaf binder so that individual sections can be replaced as needed. Each page will be dated to ease identification with respect to latest revisions. At the end of the project this Design Handbook will have become the 'as built' reference book of the injector for operations and maintenance personnel.

  13. Quantitative Auger analysis of Nb-Ge superconducting alloys

    International Nuclear Information System (INIS)

    Buitrago, R.H.

    1980-01-01

    The feasibility of using Auger electron analysis for quantitative analysis was investigated by studying Nb 3 Ge thin-film Auger data with different approaches. A method base on elemental standards gave consistent quantitative values with reported Nb-Ge data. Alloy sputter yields were also calculated and results were consistent with those for pure elements

  14. 75 FR 21680 - GE-Hitachi Global Laser Enrichment LLC;

    Science.gov (United States)

    2010-04-26

    ... Global Laser Enrichment LLC; Establishment of Atomic Safety and Licensing Board Pursuant to delegation by... over the following proceeding: GE-Hitachi Global Laser Enrichment LLC (GLE Commercial Facility) This... application of GE-Hitachi Global Laser Enrichment LLC for a license to possess and use source, byproduct, and...

  15. Thermoelectric Performance of Na-Doped GeSe

    NARCIS (Netherlands)

    Shaabani, Laaya; Aminorroaya-Yamini, Sima; Byrnes, Jacob; Akbar Nezhad, Ali; Blake, Graeme R

    2017-01-01

    Recently, hole-doped GeSe materials have been predicted to exhibit extraordinary thermoelectric performance owing largely to extremely low thermal conductivity. However, experimental research on the thermoelectric properties of GeSe has received less attention. Here, we have synthesized

  16. In-situ Ga doping of fully strained Ge1-xSnx heteroepitaxial layers grown on Ge(001) substrates

    International Nuclear Information System (INIS)

    Shimura, Y.; Takeuchi, S.; Nakatsuka, O.; Vincent, B.; Gencarelli, F.; Clarysse, T.; Vandervorst, W.; Caymax, M.; Loo, R.; Jensen, A.; Petersen, D.H.; Zaima, S.

    2012-01-01

    We have investigated the Ga and Sn content dependence of the crystallinity and electrical properties of Ga-doped Ge 1-x Sn x layers that are heteroepitaxially grown on Ge(001) substrates. The doping of Ga to levels as high as the solubility limit of Ga at the growth temperature leads to the introduction of dislocations, due to the increase in the strain of the Ge 1-x Sn x layers. We achieved the growth of a fully strained Ge 0.922 Sn 0.078 layer on Ge with a Ga concentration of 5.5 × 10 19 /cm 3 without any dislocations and stacking faults. The resistivity of the Ga-doped Ge 1-x Sn x layer decreased as the Sn content was increased. This decrease was due to an increase in the carrier concentration, with an increase in the activation level of Ga atoms in the Ge 1-x Sn x epitaxial layers being induced by the introduction of Sn. As a result, we found that the resistivity for the Ge 0.950 Sn 0.050 layer annealed at 600°C for 1 min is 3.6 times less than that of the Ga-doped Ge/Ge sample. - Highlights: ► Heavy Ga-doping into fully strained GeSn layers without the introduction of dislocations ► The uniform Ga depth profile allowed the introduction of Sn ► The decrease in resistivity with an increase in the activation level of Ga was caused by the introduction of Sn

  17. Optimization of Si–C reaction temperature and Ge thickness in C-mediated Ge dot formation

    Energy Technology Data Exchange (ETDEWEB)

    Satoh, Yuhki, E-mail: yu-ki@ecei.tohoku.ac.jp; Itoh, Yuhki; Kawashima, Tomoyuki; Washio, Katsuyoshi

    2016-03-01

    To form Ge dots on a Si substrate, the effect of thermal reaction temperature of sub-monolayer C with Si (100) was investigated and the deposited Ge thickness was optimized. The samples were prepared by solid-source molecular beam epitaxy with an electron-beam gun for C sublimation and a Knudsen cell for Ge evaporation. C of 0.25 ML was deposited on Si (100) at a substrate temperature of 200 °C, followed by a high-temperature treatment at the reaction temperature (T{sub R}) of 650–1000 °C to create Si–C bonds. Ge equivalent to 2 to 5 nm thick was subsequently deposited at 550 °C. Small and dense dots were obtained for T{sub R} = 750 °C but the dot density decreased and the dot diameter varied widely in the case of lower and higher T{sub R}. A dot density of about 2 × 10{sup 10} cm{sup −2} was achieved for Ge deposition equivalent to 3 to 5 nm thick and a standard deviation of dot diameter was the lowest of 10 nm for 5 nm thick Ge. These results mean that C-mediated Ge dot formation was strongly influenced not only by the c(4 × 4) reconstruction condition through the Si–C reaction but also the relationship between the Ge deposition thickness and the exposed Si (100)-(2 × 1) surface area. - Highlights: • The effect of Si–C reaction temperature on Ge dot formation was investigated. • Small and dense dots were obtained for T{sub R} = 750 °C. • The dot density of about 2 × 10{sup 10} cm{sup −2} was achieved for Ge = 3 to 5 nm. • The standard deviation of dot diameter was the lowest of 10 nm at Ge = 5 nm.

  18. GeNF - Experimental report 2006

    International Nuclear Information System (INIS)

    Pranzas, P.K.; Schreyer, A.; Willumeit, R.

    2007-01-01

    At the Geesthacht Neutron Facility GeNF about 212 experiments were performed in 2006 by GKSS and by or for external users, partners or contractors. In most cases the measurements were performed and analysed in cooperation by the guests and by the GKSS staff or by the permanent external user group staff. The activities, which are based on a proposal procedure and on the in house R and D program, are reported in 71 contributions in the present annual experimental report for the year 2006. The contributions may contain one or also several combined experiments. During 2006 the GKSS research reactor FRG-1 achieved an operation time of 197 days at the full 5 MW reactor power providing a neutron flux of ca. 1.4 x 10 14 thermal neutrons/cm 2 s. The cold neutron source was available during the complete operation time. The focus of the in house R and D work at GeNF instruments was the characterisation of nanostructures in engineering materials, the analysis of stresses and textures in welds and technical structures at ARES-2, TEX-2, DCD and SANS-2, the structural investigation of hydrogen containing substances such as polymers, colloids and biological macromolecules at SANS-1 as well as the characterisation of magnetic thin films at PNR, NeRo, POLDI and ROeDI. The thoroughly upgraded residual stress diffractomer ARES-2 went in full operation in spring 2006 as well as the new neutron tomography device at GENRA-3. The installation of modern experiment control hardware and software based on LabView was completed on all designated instruments. In the appendices I and II the experimental reports of REFSANS at FRM II are attached as well as of the GKSS outstation HARWI-II at DESY. Both instruments started full operation in 2006. (orig.)

  19. GeNF - experimental report 2003

    International Nuclear Information System (INIS)

    Schreyer, A.; Vollbrandt, J.; Willumeit, R.

    2004-01-01

    At the Geesthacht Neutron Facility GeNF about 210 experiments were performed in 2003 by GKSS and by or for external users, partners or contractors. In most cases the measurements were performed and analysed in cooperation by the guest and by the GKSS staff or by the permanent external user group staff. The activities, which are based on a proposal procedure and on the in house R and D program, are reported in 76 contributions in the present annual experimental report for the year 2003. The contributions may contain one or also several combined experiments. During 2003 the GKSS research reactor FRG-1 achieved an operation time of 252 days at the full 5 MW reactor power providing a neutron flux of ca. 1,4 x 10 14 thermal neutrons / cm 2 s. The cold neutron source was available during the complete operation time. The focus of the in house R and D work at GeNF instruments was the characterisation of metal alloys, the analysis of stresses in welds and technical structures at ARES, FSS, DCD and SANS-2, the structural investigation of hydrogen containing substances such as polymers, colloids and biological macromolecules at SANS-1 as well as the characterisation of magnetic thin films at PNR and ROeDI. The reflectomer TOREMA was thoroughly upgraded to the instrument NeRo and now offers new measurement possibilities. In the appendices the progress of the project REFSANS at FRM-II is reported as well as the experimental activities of the newly installed GKSS outstation HARWI-II at DESY. (orig.)

  20. GeNF - experimental report 2003

    Energy Technology Data Exchange (ETDEWEB)

    Schreyer, A; Vollbrandt, J; Willumeit, R [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. for Materials Research

    2004-07-01

    At the Geesthacht Neutron Facility GeNF about 210 experiments were performed in 2003 by GKSS and by or for external users, partners or contractors. In most cases the measurements were performed and analysed in cooperation by the guest and by the GKSS staff or by the permanent external user group staff. The activities, which are based on a proposal procedure and on the in house R and D program, are reported in 76 contributions in the present annual experimental report for the year 2003. The contributions may contain one or also several combined experiments. During 2003 the GKSS research reactor FRG-1 achieved an operation time of 252 days at the full 5 MW reactor power providing a neutron flux of ca. 1,4 x 10{sup 14} thermal neutrons / cm{sup 2} s. The cold neutron source was available during the complete operation time. The focus of the in house R and D work at GeNF instruments was the characterisation of metal alloys, the analysis of stresses in welds and technical structures at ARES, FSS, DCD and SANS-2, the structural investigation of hydrogen containing substances such as polymers, colloids and biological macromolecules at SANS-1 as well as the characterisation of magnetic thin films at PNR and ROeDI. The reflectomer TOREMA was thoroughly upgraded to the instrument NeRo and now offers new measurement possibilities. In the appendices the progress of the project REFSANS at FRM-II is reported as well as the experimental activities of the newly installed GKSS outstation HARWI-II at DESY. (orig.)

  1. GeNF - Experimental report 2006

    Energy Technology Data Exchange (ETDEWEB)

    Pranzas, P K; Schreyer, A; Willumeit, R [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. of Materials Research

    2007-07-01

    At the Geesthacht Neutron Facility GeNF about 212 experiments were performed in 2006 by GKSS and by or for external users, partners or contractors. In most cases the measurements were performed and analysed in cooperation by the guests and by the GKSS staff or by the permanent external user group staff. The activities, which are based on a proposal procedure and on the in house R and D program, are reported in 71 contributions in the present annual experimental report for the year 2006. The contributions may contain one or also several combined experiments. During 2006 the GKSS research reactor FRG-1 achieved an operation time of 197 days at the full 5 MW reactor power providing a neutron flux of ca. 1.4 x 10{sup 14} thermal neutrons/cm{sup 2}s. The cold neutron source was available during the complete operation time. The focus of the in house R and D work at GeNF instruments was the characterisation of nanostructures in engineering materials, the analysis of stresses and textures in welds and technical structures at ARES-2, TEX-2, DCD and SANS-2, the structural investigation of hydrogen containing substances such as polymers, colloids and biological macromolecules at SANS-1 as well as the characterisation of magnetic thin films at PNR, NeRo, POLDI and ROeDI. The thoroughly upgraded residual stress diffractomer ARES-2 went in full operation in spring 2006 as well as the new neutron tomography device at GENRA-3. The installation of modern experiment control hardware and software based on LabView was completed on all designated instruments. In the appendices I and II the experimental reports of REFSANS at FRM II are attached as well as of the GKSS outstation HARWI-II at DESY. Both instruments started full operation in 2006. (orig.)

  2. Hydrogen interaction kinetics of Ge dangling bonds at the Si0.25Ge0.75/SiO2 interface

    International Nuclear Information System (INIS)

    Stesmans, A.; Nguyen Hoang, T.; Afanas'ev, V. V.

    2014-01-01

    The hydrogen interaction kinetics of the GeP b1 defect, previously identified by electron spin resonance (ESR) as an interfacial Ge dangling bond (DB) defect occurring in densities ∼7 × 10 12  cm −2 at the SiGe/SiO 2 interfaces of condensation grown (100)Si/a-SiO 2 /Ge 0.75 Si 0.25 /a-SiO 2 structures, has been studied as function of temperature. This has been carried out, both in the isothermal and isochronal mode, through defect monitoring by capacitance-voltage measurements in conjunction with ESR probing, where it has previously been demonstrated the defects to operate as negative charge traps. The work entails a full interaction cycle study, comprised of analysis of both defect passivation (pictured as GeP b1 -H formation) in molecular hydrogen (∼1 atm) and reactivation (GeP b1 -H dissociation) in vacuum. It is found that both processes can be suitably described separately by the generalized simple thermal (GST) model, embodying a first order interaction kinetics description based on the basic chemical reactions GeP b1  + H 2  → GeP b1 H + H and GeP b1 H → GeP b1  + H, which are found to be characterized by the average activation energies E f  = 1.44 ± 0.04 eV and E d  = 2.23 ± 0.04 eV, and attendant, assumedly Gaussian, spreads σE f  = 0.20 ± 0.02 eV and σE d  = 0.15 ± 0.02 eV, respectively. The substantial spreads refer to enhanced interfacial disorder. Combination of the separately inferred kinetic parameters for passivation and dissociation results in the unified realistic GST description that incorporates the simultaneous competing action of passivation and dissociation, and which is found to excellently account for the full cycle data. For process times t a  ∼ 35 min, it is found that even for the optimum treatment temperature ∼380 °C, only ∼60% of the GeP b1 system can be electrically silenced, still far remote from device grade level. This

  3. Crystal structure of LaFe5Ge3O15 = LaFe5[GeO4][Ge2O7]O4

    International Nuclear Information System (INIS)

    Genkina, E.A.; Maksimov, B.A.; Mill, B.V.

    1991-01-01

    The authors have determined the structure of a new lanthanum-iron germanate LaFe 5 [GeO 4 ][GeO 4 ][Ge 2 O 7 ]O 4 (a = 18.040(4), b = 17.012(4), c = 7.591(1) angstrom, V = 2330.2(9) angstrom 3 , Z = 8, ρ t = 4.99 g/cm 3 , space ground Cmca, 1976 I hkl ≥ 3 σ(I), R = 4.5%). The compound is interesting because the framework simultaneously contains ortho- and diorthogroups of Ge and because of a classical set of coordination numbers (4,5,6) characteristic of trivalent iron within the composition of one structure. The coordination polyhedron of La has nine vertices

  4. Crystal growth kinetics in undercooled melts of pure Ge, Si and Ge-Si alloys

    Science.gov (United States)

    Herlach, Dieter M.; Simons, Daniel; Pichon, Pierre-Yves

    2018-01-01

    We report on measurements of crystal growth dynamics in semiconducting pure Ge and pure Si melts and in Ge100-xSix (x = 25, 50, 75) alloy melts as a function of undercooling. Electromagnetic levitation techniques are applied to undercool the samples in a containerless way. The growth velocity is measured by the utilization of a high-speed camera technique over an extended range of undercooling. Solidified samples are examined with respect to their microstructure by scanning electron microscopic investigations. We analyse the experimental results of crystal growth kinetics as a function of undercooling within the sharp interface theory developed by Peter Galenko. Transitions of the atomic attachment kinetics are found at large undercoolings, from faceted growth to dendrite growth. This article is part of the theme issue `From atomistic interfaces to dendritic patterns'.

  5. 20 GeV e+ x 400 GeV p: some synchrotron radiation considerations

    International Nuclear Information System (INIS)

    Humphrey, J.W.; Limon, P.J.

    1977-01-01

    The possibility of a 20 GeV electron ring in the 400 x 400 GeV 2 ISABELLE tunnel is considered. The conclusions that can be drawn from these considerations are: (1) much work remains to be done on the implications of synchrotron radiation for insertion design; (2) in the absence of considerations concerning insertion areas with longitudinal polarization, placing the electron ring in the same vertical plane as the electron ring is mildly favored; (3) creating insertions for longitudinally polarized electrons is difficult, and elementary considerations indicate that the synchrotron radiation flux in the insertion region will increase by a factor of approximately 100 and the luminosity may decrease by a factor of approximately 10; and (4) the creation of insertions for longitudinally polarized electrons favors placing the electron ring in the same horizontal plane as the proton ring

  6. Determination of core level line widths in XPS of GeS and GeSe

    International Nuclear Information System (INIS)

    Viljoen, P.E.

    1981-01-01

    Measured X-ray photoelectron spectra are broadened owing to several factors. They can be regarded as the sums of the instrument response functions and the finite source widths. By measuring the response function and deconvoluting the measured peak, the form of the measured peak, the instrument function and the deconvoluted line were determined. The former two seem to have a Gauss and the latter a Lorentz form. The X-ray source is known to have a Lorentz form. A simple method, using the shapes of all these lines, is proposed to determine the line width. Applied to GeS and GeSe lines it gives values that agree quite well with other determinations. Strictly speaking, the method is only applicable to our or other similar spectrometers, but it can be generally applied if the line shapes are known or can be determined [af

  7. Undoped and in-situ B doped GeSn epitaxial growth on Ge by atmospheric pressure-chemical vapor deposition

    DEFF Research Database (Denmark)

    Vincent, B.; Gencarelli, F.; Bender, H.

    2011-01-01

    In this letter, we propose an atmospheric pressure-chemical vapor deposition technique to grow metastable GeSn epitaxial layers on Ge. We report the growth of defect free fully strained undoped and in-situ B doped GeSn layers on Ge substrates with Sit contents up to 8%. Those metastable layers stay...

  8. Analýza procesů správy hypotéčních úvěrů ve společnosti GE Money bank a.s.

    OpenAIRE

    Andrlová, Jaroslava

    2013-01-01

    The subject of my dissertation is a process analysis of administration of Mortgage credit in G.E. Money bank Plc. The purpose of analysis is an improvement of selected process inside company. The theoretical part is dedicate to process analysis and corporate decision making process modeling.The practical part has two sections introduction of G.E Money bank Plc.basic description of Mortgage credit phases. The main part of my dissertation is a process analysis in G.E Money bank Plc. The analysi...

  9. Response function of semiconductor detectors, Ge and Si(Li); Funcao resposta de detectores semicondutores, Ge e Si(Li)

    Energy Technology Data Exchange (ETDEWEB)

    Zevallos Chavez, Juan Yury

    2003-07-01

    The Response Function (RF) for Ge and Si(Li) semiconductor detectors was obtained. The RF was calculated for five detectors, four Hp Ge with active volumes of 89 cm{sup 3} , 50 cm{sup 3} , 8 cm{sup 3} and 5 cm{sup 3}, and one Si(Li) with 0.143 cm{sup 3} of active volume. The interval of energy studied ranged from 6 keV up to 1.5 MeV. Two kinds of studies were done in this work. The first one was the RF dependence with the detection geometry. Here the calculation of the RF for a geometry named as simple and an extrapolation of that RF, were both done. The extrapolation process analyzed both, spectra obtained with a shielding geometry and spectra where the source-detector distance was modified. The second one was the RF dependence with the detection electronics. This study was done varying the shaping time of the pulse in the detection electronics. The purpose was to verify the effect of the ballistic deficit in the resolution of the detector. This effect was not observed. The RF components that describe the region of the total absorption of the energy of the incident photons, and the partial absorption of this energy, were both treated. In particular, empirical functions were proposed for the treatment of both, the multiple scattering originated in the detector (crystal), and the photon scattering originated in materials of the neighborhood of the crystal. Another study involving Monte Carlo simulations was also done in order to comprehend the photon scattering structures produced in an iron shield. A deconvolution method is suggested, for spectra related to scattered radiation in order to assess the dose delivered to the scatterer. (author)

  10. Band structure analysis in SiGe nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Amato, Michele [' Centro S3' , CNR-Istituto Nanoscienze, via Campi 213/A, 41100 Modena (Italy); Dipartimento di Scienze e Metodi dell' Ingegneria, Universita di Modena e Reggio Emilia, via Amendola 2 Pad. Morselli, I-42100 Reggio Emilia (Italy); Palummo, Maurizia [European Theoretical Spectroscopy Facility (ETSF) (Italy); CNR-INFM-SMC, Dipartimento di Fisica, Universita di Roma, ' Tor Vergata' , via della Ricerca Scientifica 1, 00133 Roma (Italy); Ossicini, Stefano, E-mail: stefano.ossicini@unimore.it [' Centro S3' , CNR-Istituto Nanoscienze, via Campi 213/A, 41100 Modena (Italy) and Dipartimento di Scienze e Metodi dell' Ingegneria, Universita di Modena e Reggio Emilia, via Amendola 2 Pad. Morselli, I-42100 Reggio Emilia (Italy) and European Theoretical Spectroscopy Facility - ETSF (Italy) and Centro Interdipartimentale ' En and Tech' , Universita di Modena e Reggio Emilia, via Amendola 2 Pad. Morselli, I-42100 Reggio Emilia (Italy)

    2012-06-05

    One of the main challenges for Silicon-Germanium nanowires (SiGe NWs) electronics is the possibility to modulate and engine their electronic properties in an easy way, in order to obtain a material with the desired electronic features. Diameter and composition constitute two crucial ways for the modification of the band gap and of the band structure of SiGe NWs. Within the framework of density functional theory we present results of ab initio calculations regarding the band structure dependence of SiGe NWs on diameter and composition. We point out the main differences with respect to the case of pure Si and Ge wires and we discuss the particular features of SiGe NWs that are useful for future technological applications.

  11. Effects of hydrogenation on magnetism of UNiGe

    Energy Technology Data Exchange (ETDEWEB)

    Adamska, A.M., E-mail: anna@mag.mff.cuni.cz [Department of Condensed Matter Physics, Charles University, Ke Karlovu 5, 12116 Prague 2 (Czech Republic); Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, al. Mickiewicza 30, 30 059 Cracow (Poland); Havela, L. [Department of Condensed Matter Physics, Charles University, Ke Karlovu 5, 12116 Prague 2 (Czech Republic); Prochazka, J. [Faculty of Sports and Physical Education, Charles University, Jose Martiho 31, 16252, Prague 6 (Czech Republic); Andreev, A.V. [Institute of Physics, Academy of Sciences, Na Slovance 2, 18221 Prague (Czech Republic); Skourski, Y. [Dresden High Magnetic Field Laboratory, Helmholtz-Zentrum Dresden-Rossendorf, 01314 Dresden (Germany)

    2011-12-15

    U-based intermetallic compound UNiGe absorbs hydrogen up to the stoichiometry UNiGeH{sub 1.2}. In analogy to other compounds with the TiNiSi-type of structure, the structure is modified into hexagonal. The zig-zag U-chains are stretched, the U-U spacing is largely enhanced and the ordering temperature increases up to 100 K. The ordered state has a spontaneous moment, but it is unlikely to be a simple ferromagnet. - Highlights: > UNiGe exhibits a variety of magnetic properties. > Hydrogenation modifies the crystal, electronic structure, and the magnetic properties. > Upon hydrogenation, the crystal symmetry of UNiGe increases from orthorhombic to hexagonal. > Magnetic ordering temperature of UNiGe (T{sub N}=44 K) is double in the hydride, possible second phase transition.

  12. Band structure analysis in SiGe nanowires

    International Nuclear Information System (INIS)

    Amato, Michele; Palummo, Maurizia; Ossicini, Stefano

    2012-01-01

    One of the main challenges for Silicon-Germanium nanowires (SiGe NWs) electronics is the possibility to modulate and engine their electronic properties in an easy way, in order to obtain a material with the desired electronic features. Diameter and composition constitute two crucial ways for the modification of the band gap and of the band structure of SiGe NWs. Within the framework of density functional theory we present results of ab initio calculations regarding the band structure dependence of SiGe NWs on diameter and composition. We point out the main differences with respect to the case of pure Si and Ge wires and we discuss the particular features of SiGe NWs that are useful for future technological applications.

  13. First evidence of low energy enhancement in Ge isotopes

    Directory of Open Access Journals (Sweden)

    Renstrøm T.

    2015-01-01

    Full Text Available The γ-strength functions and level densities of 73,74Ge have been extracted from particle-γ coincidence data using the Oslo method. In addition the γ-strength function of 74Ge above the neutron separation threshold, Sn = 10.196 MeV has been extracted from photoneutron measurements. When combined, these two experiments give a γ-strength function covering the energy range of ∼1-13 MeV for 74Ge. This thorough investigation of 74Ge is a part of an international campaign to study the previously reported low energy enhancement in this mass region in the γ-strength function from ∼3MeV towards lower γ energies. The obtained data show that both 73,74Ge display an increase in strength at low γ energies.

  14. Commissioning and operational results of the 12 GeV helium compression system at Jlab

    Energy Technology Data Exchange (ETDEWEB)

    Knudsen, Peter N. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Ganni, Venkatarao [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Dixon, Kelly D. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Norton, Robert O. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Creel, Jonathan D. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2015-12-01

    The new compressor system at Jefferson Lab (JLab) for the 12 GeV upgrade was commissioned in the spring of 2013 and incorporates many design changes, discussed in previous publications, to improve the operational range, efficiency, reliability and maintainability as compared to previous compressor skids used for this application. The 12 GeV helium compression system has five compressors configured with four pressure levels supporting three pressure levels in the new cold box. During compressor commissioning the compressors were operated independent of the cold box over a wide range of process conditions to verify proper performance including adequate cooling and oil removal. Isothermal and volumetric efficiencies over these process conditions for several built-involume ratios were obtained. This paper will discuss the operational envelope results and the modifications/improvements incorporated into the skids.

  15. Development of GE90 engine with largest thrust. GE90 engine no kaihatsu jokyo

    Energy Technology Data Exchange (ETDEWEB)

    Aono, H [Ishikawajima-Harima Heavy Industries, Co. Ltd., Tokyo (Japan)

    1994-05-01

    The present paper explained the turbofan engine GE90 which is being developed by General Electric Co., USA. That engine is to meet the thrust (takeoff thrust) of 300 to 530kN as required for the new-generation wide-fuselage civil transport plane which is being designed for its planned operation in the 1990's. In April, 1991, the world's strongest thrust of 480kN was achieved with engine elements also confirmed through element test. Thereafter, the engine underwent a flying test on board of Boeing 747 to materialize the planned operation in 1995. Made to be 9 in by-pass ratio and about 40 in overall pressure ratio, the GE90 was given the concept that advantage could be secured in both propulsive efficiency and thermal efficiency. That concept could be materialized by the development of composite fan blade technology and energy-efficient technology which were both demonstrated with an unducted fan. In spite of its pressure ratio of 22, the GE90's high pressure compressor demonstrates its polytropic efficiency which is equal to that of the low pressure ratio compressor. 3 refs., 19 figs., 1 tab.

  16. Molecular beam epitaxy growth of [CrGe/MnGe/FeGe] superlattices: Toward artificial B20 skyrmion materials with tunable interactions

    Science.gov (United States)

    Ahmed, Adam S.; Esser, Bryan D.; Rowland, James; McComb, David W.; Kawakami, Roland K.

    2017-06-01

    Skyrmions are localized magnetic spin textures whose stability has been shown theoretically to depend on material parameters including bulk Dresselhaus spin orbit coupling (SOC), interfacial Rashba SOC, and magnetic anisotropy. Here, we establish the growth of a new class of artificial skyrmion materials, namely B20 superlattices, where these parameters could be systematically tuned. Specifically, we report the successful growth of B20 superlattices comprised of single crystal thin films of FeGe, MnGe, and CrGe on Si(1 1 1) substrates. Thin films and superlattices are grown by molecular beam epitaxy and are characterized through a combination of reflection high energy electron diffraction, X-ray diffraction, and cross-sectional scanning transmission electron microscopy (STEM). X-ray energy dispersive spectroscopy (XEDS) distinguishes layers by elemental mapping and indicates good interface quality with relatively low levels of intermixing in the [CrGe/MnGe/FeGe] superlattice. This demonstration of epitaxial, single-crystalline B20 superlattices is a significant advance toward tunable skyrmion systems for fundamental scientific studies and applications in magnetic storage and logic.

  17. Strain-free Ge/GeSiSn Quantum Cascade Lasers Based on L-Valley Intersubband Transitions

    National Research Council Canada - National Science Library

    Soret, R. A; Sun, G; Cheng, H; Menendez, J; Khurgin, J

    2007-01-01

    The authors propose a Ge/Ge0.76Si0.19Sn0.05 quantum cascade laser using intersubband transitions at L valleys of the conduction band which has a clean offset of 150 meV situated below other energy valleys Gamma and X...

  18. Ab-initio calculations of semiconductor MgGeP{sub 2} and MgGeAs{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Kocak, B.; Ciftci, Y.O., E-mail: yasemin@gazi.edu.tr

    2016-05-15

    Highlights: • MgGeP{sub 2} and MgGeAs{sub 2} are semiconductor compounds. • MgGeP{sub 2} and MgGeAs{sub 2} are energetically, mechanically and dynamically stable. • The electronic charge density contour plot shows that the nature of bonding is a mixture of ionic-covalent. - Abstract: In this study, we focus on structural, electronic, elastic, lattice dynamic and optic properties of MgGeP{sub 2} and MgGeAs{sub 2} using ab-initio density-functional theory (DFT) within Armiento-Mattson 2005 (AM05) scheme of the generalized gradient approximation (GGA) for the exchange-correlation potential. Our computed structural results are in reasonable agreement with the literature. The band gap of these compounds is predicted to be direct. Our elastic results prove that these compounds are mechanically stable. The obtained phonon spectra of MgGeP{sub 2} and MgGeAs{sub 2} do not exhibit any significant imaginary branches using GGA-AM05 for the exchange-correlation approximation. Further analysis of the optical response of the dielectric functions, optical reflectivity, refractive index, extinction coefficient and electron energy loss delves into for the energy range of 0–22.5 eV. It motivated that there exists an optical polarization anisotropy of these compounds for optoelectronic device applications.

  19. A Waveform Archiving System for the GE Solar 8000i Bedside Monitor.

    Science.gov (United States)

    Fanelli, Andrea; Jaishankar, Rohan; Filippidis, Aristotelis; Holsapple, James; Heldt, Thomas

    2018-01-01

    Our objective was to develop, deploy, and test a data-acquisition system for the reliable and robust archiving of high-resolution physiological waveform data from a variety of bedside monitoring devices, including the GE Solar 8000i patient monitor, and for the logging of ancillary clinical and demographic information. The data-acquisition system consists of a computer-based archiving unit and a GE Tram Rac 4A that connects to the GE Solar 8000i monitor. Standard physiological front-end sensors connect directly to the Tram Rac, which serves as a port replicator for the GE monitor and provides access to these waveform signals through an analog data interface. Together with the GE monitoring data streams, we simultaneously collect the cerebral blood flow velocity envelope from a transcranial Doppler ultrasound system and a non-invasive arterial blood pressure waveform along a common time axis. All waveform signals are digitized and archived through a LabView-controlled interface that also allows for the logging of relevant meta-data such as clinical and patient demographic information. The acquisition system was certified for hospital use by the clinical engineering team at Boston Medical Center, Boston, MA, USA. Over a 12-month period, we collected 57 datasets from 11 neuro-ICU patients. The system provided reliable and failure-free waveform archiving. We measured an average temporal drift between waveforms from different monitoring devices of 1 ms every 66 min of recorded data. The waveform acquisition system allows for robust real-time data acquisition, processing, and archiving of waveforms. The temporal drift between waveforms archived from different devices is entirely negligible, even for long-term recording.

  20. Conductance relaxation in GeBiTe: Slow thermalization in an open quantum system

    Science.gov (United States)

    Ovadyahu, Z.

    2018-02-01

    This work describes the microstructure and transport properties of GeBixTey films with emphasis on their out-of-equilibrium behavior. Persistent-photoconductivity (PPC), previously studied in the phase-change compound GeSbxTey , is also quite prominent in this system. Much weaker PPC response is observed in the pure GeTe compound and when alloying GeTe with either In or Mn. Films made from these compounds share the same crystallographic structure, the same p -type conductivity, a similar compositional disorder extending over mesoscopic scales, and similar mosaic morphology. The enhanced photoconductive response exhibited by the Sb and Bi alloys may therefore be related to their common chemistry. Persistent photoconductivity is observable in GeBixTey films at the entire range of sheet resistances studied in this work (≈103Ω to ≈55 M Ω ). The excess conductance produced by a brief exposure to infrared illumination decays with time as a stretched exponential (Kohlrausch law). Intrinsic electron-glass effects, on the other hand, are observable in thin films of GeBixTey only for samples that are strongly localized just like it was noted with the seven electron glasses previously studied. These include a memory dip which is the defining attribute of the phenomenon. The memory dip in GeBixTey is the widest amongst the germanium-telluride alloys studied to date consistent with the high carrier concentration N ≥1021cm-3 of this compound. The thermalization process exhibited in either the PPC state or in the electron-glass regime is sluggish but the temporal law of the relaxation from the out-of-equilibrium state is distinctly different. Coexistence of the two phenomena give rise to some nontrivial effects, in particular, the visibility of the memory dip is enhanced in the PPC state. The relation between this effect and the dependence of the memory-effect magnitude on the ratio between the interparticle interaction and quench disorder is discussed.

  1. Mechanical relaxation in chalcogenide glasses of the Ge-As-S system

    International Nuclear Information System (INIS)

    Bilanych, V.S.; Melnychenko, T.D.; Rizak, V.M.; Makauz, I.I.

    2006-01-01

    The temperature and frequency-related dependences of the internal friction and the shear modulus in Ge x As 40-x S 60 glasses have been studied. The maxima of internal friction of both the relaxation and non relaxation types have been found in the low-temperature range. A relaxation maximum has been revealed in the vitrification region, and its parameters have been determined. Possible mechanisms of these processes have been discussed

  2. eDT and Model-based Configuration of 12GeV CEBAF

    Energy Technology Data Exchange (ETDEWEB)

    Turner, Dennison L. [Jefferson Lab, Newport News, VA (United States)

    2015-09-01

    This poster will discuss model-driven setup of CEBAF for the 12GeV era, focusing on the elegant Download Tool (eDT). eDT is a new operator tool that generates magnet design setpoints for various machine energies and pass configurations. eDT was developed in the effort towards a process for reducing machine configuration time and reproducibility by way of an accurate accelerator model.

  3. Integrated X-band FMCW front-end in SiGe BiCMOS

    NARCIS (Netherlands)

    Suijker, Erwin; de Boer, Lex; Visser, Guido; van Dijk, Raymond; Poschmann, Michael; van Vliet, Frank Edward

    2010-01-01

    An integrated X-band FMCW front-end is reported. The front-end unites the core functionality of an FMCW transmitter and receiver in a 0.25 μm SiGe BiCMOS process. The chip integrates a PLL for the carrier generation, and single-side band and image-reject mixers for up- and down-conversion of the

  4. Azimuthal correlations in anti pp interactions at 22.4 GeV/c

    International Nuclear Information System (INIS)

    Reimer, P.

    Data are presented on azimuthal two particle correlations and the effect is estimated of resonance production on these correlations in anti pp interactions at 22.4 GeV/c. Attention is paid to correlations between two charged pions produced in the process anti p+p→ two charged pions + anything. The dependence is described of the azimuthal asymmetry parameter on rapidity difference. (Z.J.)

  5. Fragmentation of 22Ne in emulsion at 4.1 A GeV/c

    International Nuclear Information System (INIS)

    El-Naghy, A.; Krasnov, S.A.; Tolstov, K.D.

    1987-01-01

    Charge distributions of projectile fragments produced in the interactions of 22 Ne beams with emulsion at 4.1 A GeV/c have been studied. Correlations between projectile and target fragments and among projectile fragments are presented. The change of charge yield distribution with the violence of the collision has been shown. The present analysis contradicts theoretical calculations describing the inclusive charge yield distribution of fragments by a single process

  6. Transient and temperature-dependent phenomena in Ge:Be and Ge:Zn far infrared photoconductors

    International Nuclear Information System (INIS)

    Haegel, N.M.

    1985-11-01

    An experimental study of the transient and temperature-dependent behavior of Ge:Be and Ge:Zn photoconductors has been performed under the low background photon flux conditions (p dot approx. = 10 8 photons/second) typical of astronomy and astrophysics applications. The responsivity of Ge:Be and Ge:Zn detectors is strongly temperature-dependent in closely compensated material, and the effect of compensation on free carrier lifetime in Ge:Be has been measured using the photo-Hall effect technique. Closely compensated material has been obtained by controlling the concentration of novel hydrogen-related shallow acceptor complexes, A(Be,H) and A(Zn,H), which exist in doped crystals grown under a H 2 atmosphere. A review of selection criteria for multilevel materials for optimum photoconductor performance is included. 55 refs., 47 figs

  7. GeO2/Ge structure submitted to annealing in deuterium: Incorporation pathways and associated oxide modifications

    Science.gov (United States)

    Bom, N. M.; Soares, G. V.; Hartmann, S.; Bordin, A.; Radtke, C.

    2014-10-01

    Deuterium (D) incorporation in GeO2/Ge structures following D2 annealing was investigated. Higher D concentrations were obtained for GeO2/Ge samples in comparison to their SiO2/Si counterparts annealed in the same conditions. Oxygen vacancies produced during the annealing step in D2 constitute defect sites for D incorporation, analogous to defects at the SiO2/Si interfacial region. Besides D incorporation, volatilization of the oxide layer is also observed as a consequence of D2 annealing, especially in the high temperature regime of the present study (>450 °C). In parallel to this volatilization, the stoichiometry and chemical structure of remnant oxide are modified as well. These results evidence the broader impact of forming gas annealing in dielectric/Ge structures with respect to SiO2/Si counterparts.

  8. SiGe BiCMOS manufacturing platform for mmWave applications

    Science.gov (United States)

    Kar-Roy, Arjun; Howard, David; Preisler, Edward; Racanelli, Marco; Chaudhry, Samir; Blaschke, Volker

    2010-10-01

    TowerJazz offers high volume manufacturable commercial SiGe BiCMOS technology platforms to address the mmWave market. In this paper, first, the SiGe BiCMOS process technology platforms such as SBC18 and SBC13 are described. These manufacturing platforms integrate 200 GHz fT/fMAX SiGe NPN with deep trench isolation into 0.18μm and 0.13μm node CMOS processes along with high density 5.6fF/μm2 stacked MIM capacitors, high value polysilicon resistors, high-Q metal resistors, lateral PNP transistors, and triple well isolation using deep n-well for mixed-signal integration, and, multiple varactors and compact high-Q inductors for RF needs. Second, design enablement tools that maximize performance and lowers costs and time to market such as scalable PSP and HICUM models, statistical and Xsigma models, reliability modeling tools, process control model tools, inductor toolbox and transmission line models are described. Finally, demonstrations in silicon for mmWave applications in the areas of optical networking, mobile broadband, phased array radar, collision avoidance radar and W-band imaging are listed.

  9. Thermoelectric cross-plane properties on p- and n-Ge/Si{sub x}Ge{sub 1-x} superlattices

    Energy Technology Data Exchange (ETDEWEB)

    Ferre Llin, L.; Samarelli, A. [University of Glasgow, School of Engineering, Oakfield Avenue, Glasgow G12 8LT (United Kingdom); Cecchi, S.; Chrastina, D.; Isella, G. [L-NESS, Politecnico di Milano, Via Anzani 42, 22100 Como (Italy); Müller Gubler, E. [ETH, Electron Microscopy ETH Zurich, Wolgang-Pauli-Str. Ch-8093 Zurich (Switzerland); Etzelstorfer, T.; Stangl, J. [Johannes Kepler Universität, Institute of Semiconductor and Solid State Physics, A-4040 Linz (Austria); Paul, D.J., E-mail: Douglas.Paul@glasgow.ac.uk [University of Glasgow, School of Engineering, Oakfield Avenue, Glasgow G12 8LT (United Kingdom)

    2016-03-01

    Silicon and germanium materials have demonstrated an increasing attraction for energy harvesting, due to their sustainability and integrability with complementary metal oxide semiconductor and micro-electro-mechanical-system technology. The thermoelectric efficiencies for these materials, however, are very poor at room temperature and so it is necessary to engineer them in order to compete with telluride based materials, which have demonstrated at room temperature the highest performances in literature [1]. Micro-fabricated devices consisting of mesa structures with integrated heaters, thermometers and Ohmic contacts were used to extract the cross-plane values of the Seebeck coefficient and the thermal conductivity from p- and n-Ge/Si{sub x}Ge{sub 1-x} superlattices. A second device consisting in a modified circular transfer line method structure was used to extract the electrical conductivity of the materials. A range of p-Ge/Si{sub 0.5}Ge{sub 0.5} superlattices with different doping levels was investigated in detail to determine the role of the doping density in dictating the thermoelectric properties. A second set of n-Ge/Si{sub 0.3}Ge{sub 0.7} superlattices was fabricated to study the impact that quantum well thickness might have on the two thermoelectric figures of merit, and also to demonstrate a further reduction of the thermal conductivity by scattering phonons at different wavelengths. This technique has demonstrated to lower the thermal conductivity by a 25% by adding different barrier thicknesses per period. - Highlights: • Growth of epitaxial Ge/SiGe superlattices on Si substrates as energy harvesters • Study of cross-plane thermoelectric properties of Ge/SiGe superlattices at 300 K • Thermoelectric figures of merit studied as a function of doping density • Phonon scattering at different wavelengths to reduce thermal transport.

  10. Temperature-induced assembly of semiconductor nanocrystals into fractal architectures and thermoelectric power properties in Au/Ge bilayer films

    Energy Technology Data Exchange (ETDEWEB)

    Li Quanbao; Wang Jian; Jiao Zheng [Shanghai Applied Radiation Institute, Institute of Nanochemistry and Nanobiology, School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444 (China); Wu Minghong, E-mail: mhwu@staff.shu.edu.cn [Shanghai Applied Radiation Institute, Institute of Nanochemistry and Nanobiology, School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444 (China); Shek, Chan-Hung; Lawrence Wu, C.M.; Lai, Joseph K.L. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Chen Zhiwen, E-mail: cnzwchen@yahoo.com.cn [Shanghai Applied Radiation Institute, Institute of Nanochemistry and Nanobiology, School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444 (China); Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong)

    2011-08-15

    Highlights: > Ge fractal architectures were achieved by temperature-induced assembly. > The appearance of fractal architectures influences the thermoelectric power. > But it has little effect on the resistivity. > The values of the superlocalization exponent were within 1.22 {<=} {xi} {<=} 1.29. > It was higher than expected for two-dimension fractal system. - Abstract: Fractal architectures of semiconductor nanocrystals were successfully achieved by temperature-induced assembly of semiconductor nanocrystals in gold/germanium (Au/Ge) bilayer films. New assessment strategies of fractal architectures are of fundamental importance in the development of micro/nano-devices. Temperature-dependent properties including resistivity and thermoelectric power (TEP) of Au/Ge bilayer films with self-similar fractal patterns were investigated in detail. Experimental results indicated that the microstructure of Au film plays an important role in the characteristics of Au/Ge bilayer films after annealing and the crystallization processes of amorphous Ge accompany by fractal formation of Ge nanocrystals via temperature-induced assembly. The appearance of fractal architectures has significantly influence on the TEP but little effect on the resistivity of the annealed bilayer film. By analysis of the data, we found that the values of superlocalization exponent are within 1.22 {<=} {xi} {<=} 1.29, which are higher than expected for two-dimension fractal systems. The results provided possible evidence for the superlocalization on fractal architectures in Au/Ge bilayer films. The TEP measurements are considered a more effective method than the conductivity for investigating superlocalization in a percolating system.

  11. (Zn, Mg)2GeO4:Mn2+ submicrorods as promising green phosphors for field emission displays: hydrothermal synthesis and luminescence properties.

    Science.gov (United States)

    Shang, Mengmeng; Li, Guogang; Yang, Dongmei; Kang, Xiaojiao; Peng, Chong; Cheng, Ziyong; Lin, Jun

    2011-10-07

    (Zn(1-x-y)Mg(y))(2)GeO(4): xMn(2+) (y = 0-0.30; x = 0-0.035) phosphors with uniform submicrorod morphology were synthesized through a facile hydrothermal process. X-Ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), photoluminescence (PL), and cathodoluminescence (CL) spectroscopy were utilized to characterize the samples. SEM and TEM images indicate that Zn(2)GeO(4):Mn(2+) samples consist of submicrorods with lengths around 1-2 μm and diameters around 200-250 nm, respectively. The possible formation mechanism for Zn(2)GeO(4) submicrorods has been presented. PL and CL spectroscopic characterizations show that pure Zn(2)GeO(4) sample shows a blue emission due to defects, while Zn(2)GeO(4):Mn(2+) phosphors exhibit a green emission corresponding to the characteristic transition of Mn(2+) ((4)T(1)→(6)A(1)) under the excitation of UV and low-voltage electron beam. Compared with Zn(2)GeO(4):Mn(2+) sample prepared by solid-state reaction, Zn(2)GeO(4):Mn(2+) phosphors obtained by hydrothermal process followed by high temperature annealing show better luminescence properties. In addition, codoping Mg(2+) ions into the lattice to substitute for Zn(2+) ions can enhance both the PL and CL intensity of Zn(2)GeO(4):Mn(2+) phosphors. Furthermore, Zn(2)GeO(4):Mn(2+) phosphors exhibit more saturated green emission than the commercial FEDs phosphor ZnO:Zn, and it is expected that these phosphors are promising for application in field-emission displays.

  12. Pulse shape discrimination performance of inverted coaxial Ge detectors

    Science.gov (United States)

    Domula, A.; Hult, M.; Kermaïdic, Y.; Marissens, G.; Schwingenheuer, B.; Wester, T.; Zuber, K.

    2018-05-01

    We report on the characterization of two inverted coaxial Ge detectors in the context of being employed in future 76Ge neutrinoless double beta (0 νββ) decay experiments. It is an advantage that such detectors can be produced with bigger Ge mass as compared to the planar Broad Energy Ge (BEGe) or p-type Point Contact (PPC) detectors that are currently used in the GERDA and MAJORANA DEMONSTRATOR 0 νββ decay experiments respectively. This will result in a lower background for the search of 0 νββ decay due to a reduction of detector surface to volume ratio, cables, electronics and holders which are dominating nearby radioactive sources. The measured resolution near the 76Ge Q-value at 2039 keV is 2.3 keV FWHM and their pulse-shape discrimination of background events are similar to BEGe and PPC detectors. It is concluded that this type of Ge-detector is suitable for usage in 76Ge 0 νββ decay experiments.

  13. GeNF - Experimental report 2008

    Energy Technology Data Exchange (ETDEWEB)

    Pranzas, Philipp Klaus; Mueller, Martin; Willumeit, Regine; Schreyer, Andreas [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Materialforschung

    2009-12-11

    At the Geesthacht Neutron Facility GeNF about 182 experiments were performed in 2008 by GKSS and by or for external users, partners or contractors. In most cases the measurements were performed and analysed in cooperation by the guests, by GKSS staff or by the permanent external user group staff. The activities, which are based on a proposal procedure and on the in house R and D program, are reported in 76 contributions in the present annual experimental report for the year 2008. The contributions may contain several combined experiments. During 2008 the GKSS research reactor FRG-1 achieved an operation time of 175 days at the full 5 MW reactor power providing a neutron flux of ca. 1.4.10{sup 14} thermal neutrons/cm{sup 2} s. The focus of the in house R and D work at GeNF instruments in 2008 was the characterisation of nanostructures in engineering materials, the analysis of stresses and textures in welds and technical structures at SANS-2, DCD, ARES-2 and TEX-2, the structural investigation of hydrogen containing substances such as polymers, colloids and biological macromolecules at SANS-1 as well as the characterisation of magnetic thin films at NeRo, PNR, POLDI and ROeDI. The modern experiment control hardware (e.g. sample environments, like magnets, cryostats or furnaces) and software based on LabView was continuously improved on all instruments. In the appendices I and II the experimental reports of the GKSS outstation at the FRM II are attached as well as of the GKSS outstation at DESY. The massive activity at the FRM II outstation is documented by the increasing number of REFSANS reports, accumulated to nine. Three reports show the activities of GKSS in the field of texture measurement at the instrument STRESS-SPEC. The instrument HARWI II at the synchrotron storage ring DORIS III at DESY is accepted very well by the community and is heavily overbooked in all fields (tomography, diffraction, etc.). After an 8-month shutdown period for an upgrade in the frame

  14. GeNF - Experimental report 2008

    International Nuclear Information System (INIS)

    Pranzas, Philipp Klaus; Mueller, Martin; Willumeit, Regine; Schreyer, Andreas

    2009-01-01

    At the Geesthacht Neutron Facility GeNF about 182 experiments were performed in 2008 by GKSS and by or for external users, partners or contractors. In most cases the measurements were performed and analysed in cooperation by the guests, by GKSS staff or by the permanent external user group staff. The activities, which are based on a proposal procedure and on the in house R and D program, are reported in 76 contributions in the present annual experimental report for the year 2008. The contributions may contain several combined experiments. During 2008 the GKSS research reactor FRG-1 achieved an operation time of 175 days at the full 5 MW reactor power providing a neutron flux of ca. 1.4.10 14 thermal neutrons/cm 2 s. The focus of the in house R and D work at GeNF instruments in 2008 was the characterisation of nanostructures in engineering materials, the analysis of stresses and textures in welds and technical structures at SANS-2, DCD, ARES-2 and TEX-2, the structural investigation of hydrogen containing substances such as polymers, colloids and biological macromolecules at SANS-1 as well as the characterisation of magnetic thin films at NeRo, PNR, POLDI and ROeDI. The modern experiment control hardware (e.g. sample environments, like magnets, cryostats or furnaces) and software based on LabView was continuously improved on all instruments. In the appendices I and II the experimental reports of the GKSS outstation at the FRM II are attached as well as of the GKSS outstation at DESY. The massive activity at the FRM II outstation is documented by the increasing number of REFSANS reports, accumulated to nine. Three reports show the activities of GKSS in the field of texture measurement at the instrument STRESS-SPEC. The instrument HARWI II at the synchrotron storage ring DORIS III at DESY is accepted very well by the community and is heavily overbooked in all fields (tomography, diffraction, etc.). After an 8-month shutdown period for an upgrade in the frame of the

  15. GeNF - Experimental report 2007

    Energy Technology Data Exchange (ETDEWEB)

    Pranzas, P K; Schreyer, A; Willumeit, R [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Materialforschung

    2008-11-05

    At the Geesthacht Neutron Facility GeNF about 203 experiments were performed in 2007 by GKSS and by or for external users, partners or contractors. In most cases the measurements were performed and analysed in cooperation by the guests and by the GKSS staff or by the permanent external user group staff. The activities, which are based on a proposal procedure and on the in house R and D program, are reported in 70 contributions in the present annual experimental report for the year 2007. The contributions may contain one or also several combined experiments. During 2007 the GKSS research reactor FRG-1 achieved an operation time of 204 days at the full 5 MW reactor power providing a neutron flux of ca. 1.4 x 10{sup 14} thermal neutrons/cm{sup 2}s. In May/June 2007 the FRG-1 was upgraded with a new cold neutron source yielding a flux increase at the five instruments using cold neutrons of up to 40 %. The focus of the in house R and D work at GeNF instruments in 2007 was the characterisation of nano-structures in engineering materials, the analysis of stresses and textures in welds and technical structures at SANS-2, DCD, ARES-2 and TEX-2, the structural investigation of hydrogen containing substances such as polymers, colloids and biological macromolecules at SANS-1 as well as the characterisation of magnetic thin films at NeRo, PNR, POLDI and ROeDI. The modern experiment control hardware and software based on LabView was continuously improved on all instruments. In the appendices I and II the experimental reports of the GKSS outstation at the FRM II are attached as well as of the GKSS outstation at DESY. At the neutron reflectometer REFSANS at FRM II measurements are possible using a broad range of the scattering vector with reflectivities up to 10{sup -7}. Three reports show the activities of GKSS in the field of texture measurement at the instrument STRESS-SPEC. The instrument HARWI II at DESY is accepted very well by the community and is overbooked in all fields

  16. GeNF - Experimental report 2007

    International Nuclear Information System (INIS)

    Pranzas, P.K.; Schreyer, A.; Willumeit, R.

    2008-01-01

    At the Geesthacht Neutron Facility GeNF about 203 experiments were performed in 2007 by GKSS and by or for external users, partners or contractors. In most cases the measurements were performed and analysed in cooperation by the guests and by the GKSS staff or by the permanent external user group staff. The activities, which are based on a proposal procedure and on the in house R and D program, are reported in 70 contributions in the present annual experimental report for the year 2007. The contributions may contain one or also several combined experiments. During 2007 the GKSS research reactor FRG-1 achieved an operation time of 204 days at the full 5 MW reactor power providing a neutron flux of ca. 1.4 x 10 14 thermal neutrons/cm 2 s. In May/June 2007 the FRG-1 was upgraded with a new cold neutron source yielding a flux increase at the five instruments using cold neutrons of up to 40 %. The focus of the in house R and D work at GeNF instruments in 2007 was the characterisation of nano-structures in engineering materials, the analysis of stresses and textures in welds and technical structures at SANS-2, DCD, ARES-2 and TEX-2, the structural investigation of hydrogen containing substances such as polymers, colloids and biological macromolecules at SANS-1 as well as the characterisation of magnetic thin films at NeRo, PNR, POLDI and ROeDI. The modern experiment control hardware and software based on LabView was continuously improved on all instruments. In the appendices I and II the experimental reports of the GKSS outstation at the FRM II are attached as well as of the GKSS outstation at DESY. At the neutron reflectometer REFSANS at FRM II measurements are possible using a broad range of the scattering vector with reflectivities up to 10 -7 . Three reports show the activities of GKSS in the field of texture measurement at the instrument STRESS-SPEC. The instrument HARWI II at DESY is accepted very well by the community and is overbooked in all fields (tomography

  17. An investigation of proton pair correlations relevant to the neutrinoless double beta decay of 76Ge

    Science.gov (United States)

    Ticehurst, David R.

    The observation of neutrinoless double beta decay (0nubetabeta ) would demonstrate that the neutrino is a Majorana particle and allow determination of its mass by comparing the measured decay rate to the calculated rate. The main uncertainty in the calculation of the 0 nubetabeta rate is due to uncertainties in the nuclear structure models used in the computation of the nuclear matrix elements for the decay process. This project tested the validity of using wavefunctions for the nuclear states involved in the 0nubetabeta process that are based on a first-order application of the Bardeen-Cooper-Schrieffer (BCS) theory of superconductivity. In the BCS approximation, most of the strength for two-nucleon transfer reactions should be for transitions to the 0 + ground state of the final nucleus (i.e., little strength should go to the 0+ excited states). This experiment measured the strength to the first 0+ excited state for the 74Ge( 3He,n)76Se and 76Ge( 3He,n)78Se reactions relative to the strength for transition to the 0+ ground state in selenium. For both nuclei, and at 3He beam energies of 15 and 21 MeV, the observed relative strength for transfer to the first 0+ excited state was less than 13%. This result supports the validity of using the BCS approximation to describe the ground state of both 76Se and 78Se and is consistent with the results of recent ( 3He,n) cross section measurements on 74Ge and 76Ge. In addition, the magnitude and shape of the measured angular distributions suggest that contribution of the sequential two-nucleon transfer process, which is an indicator of long-range nucleon-nucleon correlations, is over-predicted by the DWBA code FRESCO.

  18. Photon pair production by e/sup +/e/sup -/ annihilation and search for supersymmetric photinos at energies greater than 40 GeV

    Energy Technology Data Exchange (ETDEWEB)

    Althoff, M; Braunschweig, W; Kirschfink, F J; Luebelsmeyer, K; Martyn, H U; Rosskamp, R; Schmitz, D; Siebke, H; Wallraff, W; Eisenmann, J

    1984-12-01

    The cross section for the process e/sup +/e/sup -/->..gamma gamma.. has been measured for c.m. energies 39.5 < W < 46.8 GeV. Good agreement with the predictions of QED was found and lower limits for the cut-off parameters of 6 GeV (95% confidence level) have been determined. A search for two photon final states with missing energy provided lower limits on the masses of the photino and selectron.

  19. Deuteron-deuteron scattering at 3.0, 3.4 and 3.7 GeV/c, theoretical interpretation in the Glauber model

    International Nuclear Information System (INIS)

    Ballot, J.L.; L'Huillier, M.; Combes, M.P.; Tatischeff, B.

    1984-01-01

    An analysis of deuteron-deuteron scattering data at 3.0, 3.4 and 3.7 GeV/c is given in the framework of the Glauber NN multiple scattering model. The model accounts qualitatively well for the larger momentum transfer data. The model cannot reproduce the observed experimental bump at small transfer in the region of missing mass 2GeV/c, because pionic processes have been considered. Nevertheless it shows that the nucleon background is important

  20. Theory and design aspects of the 1 GeV proton compressor ring for pulsed beams of spallation neutrons and muons

    International Nuclear Information System (INIS)

    Rees, G.H.

    1988-05-01

    In the present paper, an outline design is presented for a 50 Hz, 1 GeV proton compressor ring of Japanese Hadron Project. The design aims are to provide two pulses of 1 GeV protons with an average current of 200 μA, one pulse with the time duration of 20 ns and the other of 100 - 200 ns. Very important aspects of magnet lattice, injection scheme, bunch compression process, beam instabilities are discussed. (author)

  1. Observation of e(+)e(-) -> eta ' J/psi center-of-mass energies between 4.189 and 4.600 GeV

    NARCIS (Netherlands)

    Ablikim, M.; Achasov, M. N.; Ahmed, S.; Ai, X. C.; Albayrak, O.; Albrecht, M.; Ambrose, D. J.; Amoroso, A.; An, F. F.; An, Q.; Bai, J. Z.; Ferroli, R. Baldini; Ban, Y.; Bennett, D. W.; Bennett, J. V.; Berger, N.; Bertani, M.; Bettoni, D.; Bian, J. M.; Bianchi, F.; Boger, E.; Boyko, I.; Briere, R. A.; Cai, H.; Cai, X.; Cakir, O.; Calcaterra, A.; Cao, G. F.; Cetin, S. A.; Chang, J. F.; Chelkov, G.; Chen, G.; Chen, H. S.; Chen, H. Y.; Chen, J. C.; Chen, M. L.; Chen, S.; Chen, S. J.; Chen, X.; Chen, X. R.; Chen, Y. B.; Cheng, H. P.; Chu, X. K.; Cibinetto, G.; Dai, H. L.; Dai, J. P.; Dbeyssi, A.; Dedovich, D.; Deng, Z. Y.; Denig, A.; Denysenko, I.; Destefanis, M.; De Mori, F.; Ding, Y.; Dong, C.; Dong, J.; Dong, L. Y.; Dong, M. Y.; Dou, Z. L.; Du, S. X.; Duan, P. F.; Fan, J. Z.; Fang, J.; Fang, S. S.; Fang, X.; Fang, Y.; Farinelli, R.; Fava, L.; Fedorov, O.; Feldbauer, F.; Felici, G.; Feng, C. Q.; Fioravanti, E.; Fritsch, M.; Fu, C. D.; Gao, Q.; Gao, X. L.; Gao, X. Y.; Gao, Y.; Gao, Z.; Garzia, I.; Goetzen, K.; Gong, L.; Gong, W. X.; Gradl, W.; Greco, M.; Gu, M. H.; Gu, Y. T.; Guan, Y. H.; Guo, A. Q.; Guo, L. B.; Guo, R. P.; Guo, Y.; Guo, Y. P.; Haddadi, Z.; Hafner, A.; Han, S.; Hao, X. Q.; Harris, F. A.; He, K. L.; Heinsius, F. H.; Held, T.; Heng, Y. K.; Holtmann, T.; Hou, Z. L.; Hu, C.; Hu, H. M.; Hu, J. F.; Hu, T.; Hu, Y.; Huang, G. S.; Huang, J. S.; Huang, X. T.; Huang, X. Z.; Huang, Y.; Huang, Z. L.; Hussain, T.; Ji, Q.; Ji, Q. P.; Ji, X. B.; Ji, X. L.; Jiang, L. W.; Jiang, X. S.; Jiang, X. Y.; Jiao, J. B.; Jiao, Z.; Jin, D. P.; Jin, S.; Johansson, T.; Julin, A.; Kalantar-Nayestanaki, N.; Kang, X. L.; Kang, X. S.; Kavatsyuk, M.; Ke, B. C.; Kiese, P.; Kliemt, R.; Kloss, B.; Kolcu, O. B.; Kopf, B.; Kornicer, M.; Kupsc, A.; Kuehn, W.; Lange, J. S.; Lara, M.; Larin, P.; Leithoff, H.; Leng, C.; Li, C.; Li, Cheng; Li, D. M.; Li, F.; Li, F. Y.; Li, G.; Li, H. B.; Li, H. J.; Li, J. C.; Li, Jin; Li, K.; Li, K.; Li, Lei; Li, P. R.; Li, Q. Y.; Li, T.; Li, W. D.; Li, W. G.; Li, X. L.; Li, X. N.; Li, X. Q.; Li, Y. B.; Li, Z. B.; Liang, H.; Liang, Y. F.; Liang, Y. T.; Liao, G. R.; Lin, D. X.; Liu, B.; Liu, B. J.; Liu, C. X.; Liu, D.; Liu, F. H.; Liu, Fang; Liu, Feng; Liu, H. B.; Liu, H. H.; Liu, H. H.; Liu, H. M.; Liu, J.; Liu, J. B.; Liu, J. P.; Liu, J. Y.; Liu, K.; Liu, K. Y.; Liu, L. D.; Liu, P. L.; Liu, Q.; Liu, S. B.; Liu, X.; Liu, Y. B.; Liu, Y. Y.; Liu, Z. A.; Liu, Zhiqing; Loehner, H.; Lou, X. C.; Lu, H. J.; Lu, J. G.; Lu, Y.; Lu, Y. P.; Luo, C. L.; Luo, M. X.; Luo, T.; Luo, X. L.; Lyu, X. R.; Ma, F. C.; Ma, H. L.; Ma, L. L.; Ma, M. M.; Ma, Q. M.; Ma, T.; Ma, X. N.; Ma, X. Y.; Ma, Y. M.; Maas, F. E.; Maggiora, M.; Mao, Y. J.; Mao, Z. P.; Marcello, S.; Messchendorp, J. G.; Mezzadri, G.; Min, J.; Mitchell, R. E.; Mo, X. H.; Mo, Y. J.; Morales, C. Morales; Muchnoi, N. Yu.; Muramatsu, H.; Musiol, P.; Nefedov, Y.; Nerling, F.; Nikolaev, I. B.; Ning, Z.; Nisar, S.; Niu, S. L.; Niu, X. Y.; Olsen, S. L.; Ouyang, Q.; Pacetti, S.; Pan, Y.; Patteri, P.; Pelizaeus, M.; Peng, H. P.; Peters, K.; Pettersson, J.; Ping, J. L.; Ping, R. G.; Poling, R.; Prasad, V.; Qi, H. R.; Qi, M.; Qian, S.; Qiao, C. F.; Qin, L. Q.; Qin, N.; Qin, X. S.; Qin, Z. H.; Qiu, J. F.; Rashid, K. H.; Redmer, C. F.; Ripka, M.; Rong, G.; Rosner, Ch.; Ruan, X. D.; Sarantsev, A.; Savrie, M.; Schnier, C.; Schoenning, K.; Schumann, S.; Shan, W.; Shao, M.; Shen, C. P.; Shen, P. X.; Shen, X. Y.; Sheng, H. Y.; Shi, M.; Song, W. M.; Song, X. Y.; Sosio, S.; Spataro, S.; Sun, G. X.; Sun, J. F.; Sun, S. S.; Sun, X. H.; Sun, Y. J.; Sun, Y. Z.; Sun, Z. J.; Sun, Z. T.; Tang, C. J.; Tang, X.; Tapan, I.; Thorndike, E. H.; Tiemens, M.; Uman, I.; Varner, G. S.; Wang, B.; Wang, B. L.; Wang, D.; Wang, D. Y.; Wang, K.; Wang, L. L.; Wang, L. S.; Wang, M.; Wang, P.; Wang, P. L.; Wang, S. G.; Wang, W.; Wang, W. P.; Wang, X. F.; Wang, Y.; Wang, Y. D.; Wang, Y. F.; Wang, Y. Q.; Wang, Z.; Wang, Z. G.; Wang, Z. H.; Wang, Z. Y.; Wang, Z. Y.; Weber, T.; Wei, D. H.; Wei, J. B.; Weidenkaff, P.; Wen, S. P.; Wiedner, U.; Wolke, M.; Wu, L. H.; Wu, L. J.; Wu, Z.; Xia, L.; Xia, L. G.; Xia, Y.; Xiao, D.; Xiao, H.; Xiao, Z. J.; Xie, Y. G.; Xiu, Q. L.; Xu, G. F.; Xu, J. J.; Xu, L.; Xu, Q. J.; Xu, Q. N.; Xu, X. P.; Yan, L.; Yan, W. B.; Yan, W. C.; Yan, Y. H.; Yang, H. J.; Yang, H. X.; Yang, L.; Yang, Y. X.; Ye, M.; Ye, M. H.; Yin, J. H.; Yu, B. X.; Yu, C. X.; Yu, J. S.; Yuan, C. Z.; Yuan, W. L.; Yuan, Y.; Yuncu, A.; Zafar, A. A.; Zallo, A.; Zeng, Y.; Zeng, Z.; Zhang, B. X.; Zhang, B. Y.; Zhang, C.; Zhang, C. C.; Zhang, D. H.; Zhang, H. H.; Zhang, H. Y.; Zhang, J.; Zhang, J. J.; Zhang, J. L.; Zhang, J. Q.; Zhang, J. W.; Zhang, J. Y.; Zhang, J. Z.; Zhang, K.; Zhang, L.; Zhang, S. Q.; Zhang, X. Y.; Zhang, Y.; Zhang, Y. H.; Zhang, Y. N.; Zhang, Y. T.; Zhang, Yu; Zhang, Z. H.; Zhang, Z. P.; Zhang, Z. Y.; Zhao, G.; Zhao, J. W.; Zhao, J. Y.; Zhao, J. Z.; Zhao, Lei; Zhao, Ling; Zhao, M. G.; Zhao, Q.; Zhao, Q. W.; Zhao, S. J.; Zhao, T. C.; Zhao, Y. B.; Zhao, Z. G.; Zhemchugov, A.; Zheng, B.; Zheng, J. P.; Zheng, W. J.; Zheng, Y. H.; Zhong, B.; Zhou, L.; Zhou, X.; Zhou, X. K.; Zhou, X. R.; Zhou, X. Y.; Zhu, K.; Zhu, K. J.; Zhu, S.; Zhu, S. H.; Zhu, X. L.; Zhu, Y. C.; Zhu, Y. S.; Zhu, Z. A.; Zhuang, J.; Zotti, L.; Zou, B. S.; Zou, J. H.

    2016-01-01

    The process e(+)e(-) -> eta' J/psi is observed for the first time with a statistical significance of 8.6 sigma at center-of-mass energy root s = 4.226 GeV and 7.3 sigma at root s = 4.258 GeV using data samples collected with the BESIII detector. The Born cross sections are measured to be (3.7 +/-

  2. Efficient tunable luminescence of SiGe alloy sheet polymers

    International Nuclear Information System (INIS)

    Vogg, G.; Meyer, A. J.-P.; Miesner, C.; Brandt, M. S.; Stutzmann, M.

    2001-01-01

    Crystalline SiGe alloy sheet polymers were topotactically prepared from epitaxially grown calcium germanosilicide Ca(Si 1-x Ge x ) 2 precursor films in the whole composition range. These polygermanosilynes are found to be a well-defined mixture of the known siloxene and polygermyne sheet polymers with the OH groups exclusively bonded to silicon. The optical properties determined by photoluminescence and optical reflection measurements identify the mixed SiGe sheet polymers as direct semiconductors with efficient luminescence tunable in the energy range between 2.4 and 1.3 eV. [copyright] 2001 American Institute of Physics

  3. A CoGeNT confirmation of the DAMA signal

    International Nuclear Information System (INIS)

    Foot, R.

    2010-01-01

    The CoGeNT Collaboration has recently reported a rising low energy spectrum in their ultra low noise Germanium detector. This is particularly interesting as the energy range probed by CoGeNT overlaps with the energy region in which DAMA has observed their annual modulation signal. We show that the mirror dark matter candidate can simultaneously explain both the DAMA annual modulation signal and the rising low energy spectrum observed by CoGeNT. This constitutes a model dependent confirmation of the DAMA signal and adds weight to the mirror dark matter paradigm.

  4. Development of high responsivity Ge:Ga photoconductors

    International Nuclear Information System (INIS)

    Haegel, N.M.; Hueschen, M.R.; Haller, E.E.

    1984-06-01

    Czochralski-grown gallium-doped germanium (Ge:Ga) single crystal samples with a compensation of 10 -4 have been modified by the indiffusion of Cu to produce photoconductors which provide NEPs comparable to current optimum Ge:Ga detectors, but exhibit responsivities a factor of 5 to 6 times higher when tested at a background photon flux of 10 8 photons/sec at lambda=93 μm. The introduction of Cu, a triple acceptor in Ge which acts as a neutral scattering center, reduces carrier mobility and extends the breakdown field significantly in this ultra-low compensation material

  5. Spin-polarized photoemission from SiGe heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Ferrari, A.; Bottegoni, F.; Isella, G.; Cecchi, S.; Chrastina, D.; Finazzi, M.; Ciccacci, F. [LNESS-Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano (Italy)

    2013-12-04

    We apply the principles of Optical Orientation to measure by Mott polarimetry the spin polarization of electrons photoemitted from different group-IV heterostructures. The maximum measured spin polarization, obtained from a Ge/Si{sub 0.31}Ge{sub 0.69} strained film, undoubtedly exceeds the maximum value of 50% attainable in bulk structures. The explanation we give for this result lies in the enhanced band orbital mixing between light hole and split-off valence bands as a consequence of the compressive strain experienced by the thin Ge layer.

  6. Soft chemistry routes to GeS2 nanoparticles

    Science.gov (United States)

    Courthéoux, Laurence; Mathiaud, Romain; Ribes, Michel; Pradel, Annie

    2018-04-01

    Spherical GeS2 particles are prepared by a low temperature liquid route with TEOG as germanium precursor and either H2S or thioacetamide (TAA) as sulfur precursors. The size and agglomeration of the particles change depending upon the temperature and nature of the solvent. Most synthesis lead to preparing amorphous GeS2. When the reaction kinetic is slowed down by using TAA at 25 °C, the obtained GeS2 product presents a larger order in the range of few Å as proven by Raman spectroscopy, even though it is still an amorphous compound as suggested by X-Ray diffraction and TEM experiments.

  7. Gadolinium scandium germanide, Gd2Sc3Ge4

    Directory of Open Access Journals (Sweden)

    Sumohan Misra

    2009-04-01

    Full Text Available Gd2Sc3Ge4 adopts the orthorhombic Pu5Rh4-type structure. The crystal structure contains six sites in the asymmetric unit: two sites are statistically occupied by rare-earth atoms with Gd:Sc ratios of 0.967 (4:0.033 (4 and 0.031 (3:0.969 (3, one site (.m. symmetry is occupied by Sc atoms, and three distinct sites (two of which with .m. symmetry are occupied by Ge atoms. The rare-earth atoms form two-dimensional slabs with Ge atoms occupying the trigonal-prismatic voids.

  8. Muonium hyperfine parameters in Si1-x Ge x alloys

    International Nuclear Information System (INIS)

    King, Philip; Lichti, Roger; Cottrell, Stephen; Yonenaga, Ichiro

    2006-01-01

    We present studies of muonium behaviour in bulk, Czochralski-grown Si 1- x Ge x alloy material, focusing in particular on the hyperfine parameter of the tetrahedral muonium species. In contrast to the bond-centred species, the hyperfine parameter of the tetrahedral-site muonium centre (Mu T ) appears to vary non-linearly with alloy composition. The temperature dependence of the Mu T hyperfine parameter observed in low-Ge alloy material is compared with that seen in pure Si, and previous models of the Mu T behaviour in Si are discussed in the light of results from Si 1- x Ge x alloys

  9. High-pressure structural behaviour of nanocrystalline Ge

    International Nuclear Information System (INIS)

    Wang, H; Liu, J F; He, Y; Wang, Y; Chen, W; Jiang, J Z; Olsen, J Staun; Gerward, L

    2007-01-01

    The equation of state and the pressure of the I-II transition have been studied for nanocrystalline Ge using synchrotron x-ray diffraction. The bulk modulus and the transition pressure increase with decreasing particle size for both Ge-I and Ge-II, but the percentage volume collapse at the transition remains constant. Simplified models for the high-pressure structural behaviour are presented, based on the assumption that a large fraction of the atoms reside in grain boundary regions of the nanocrystalline material. The interface structure plays a significant role in affecting the transition pressure and the bulk modulus

  10. Interaction of slow neutrons with 74Ge single crystals

    International Nuclear Information System (INIS)

    Pshenichnyj, V.A.; Pak En Men; Vorobkalo, F.M.; Vertebnyj, V.P.

    1986-01-01

    The total cross section of monocrystal from germanium-74 isotope by the time-of-flight method in the 0.017-10 eV range is measured. At room temperatures the above monocrystal possesses the capability of separating from the white reactor spectrum intensive beams of thermal neutrons. It is shown that the 74 Ge monocrystal by its filtering properties approaches to the Si monocrystal. The observed cross sections for Si, Ge, 74 Ge monocrystals in the thermal region of neutron energy are indicated in the study

  11. Recent progress in GeSi electro-absorption modulators

    International Nuclear Information System (INIS)

    Chaisakul, Papichaya; Marris-Morini, Delphine; Rouifed, Mohamed-Said; Coudevylle, Jean-René; Roux, Xavier Le; Edmond, Samson; Vivien, Laurent; Frigerio, Jacopo; Chrastina, Daniel; Isella, Giovanni

    2014-01-01

    Electro-absorption from GeSi heterostructures is receiving growing attention as a high performance optical modulator for short distance optical interconnects. Ge incorporation with Si allows strong modulation mechanism using the Franz–Keldysh effect and the quantum-confined Stark effect from bulk and quantum well structures at telecommunication wavelengths. In this review, we discuss the current state of knowledge and the on-going challenges concerning the development of high performance GeSi electro-absorption modulators. We also provide feasible future prospects concerning this research topic. (review)

  12. Ge L{sub 3}-edge x-ray absorption near-edge structure study of structural changes accompanying conductivity drift in the amorphous phase of Ge{sub 2}Sb{sub 2}Te{sub 5}

    Energy Technology Data Exchange (ETDEWEB)

    Mitrofanov, K. V. [Nanoelectronics Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba 305-8562 (Japan); Kolobov, A. V., E-mail: a.kolobov@aist.go.jp; Fons, P. [Nanoelectronics Research Institute and Green Nanoelectronics Center, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba 305-8562, Japan and Synchrotron Radiation Research Institute (JASRI), SPring-8, 1-1-1, Kouto, Sayo, Hyogo 679-5198 (Japan); Wang, X.; Tominaga, J. [Nanoelectronics Research Institute and Green Nanoelectronics Center, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba 305-8562 (Japan); Tamenori, Y.; Uruga, T. [Synchrotron Radiation Research Institute (JASRI), SPring-8, 1-1-1, Kouto, Sayo, Hyogo 679-5198 (Japan); Ciocchini, N.; Ielmini, D. [DEIB - Politecnico di Milano, Piazza L. Da Vinci 32, 20133 Milano (Italy)

    2014-05-07

    A gradual uncontrollable increase in the resistivity of the amorphous phase of phase-change alloys, such as Ge{sub 2}Sb{sub 2}Te{sub 5}, known as drift, is a serious technological issue for application of phase-change memory. While it has been proposed that drift is related to structural relaxation, no direct structural results have been reported so far. Here, we report the results of Ge L{sub 3}-edge x-ray absorption measurements that suggest that the drift in electrical conductivity is associated with the gradual conversion of tetrahedrally coordinated Ge sites into pyramidal sites, while the system still remains in the amorphous phase. Based on electronic configuration arguments, we propose that during this process, which is governed by the existence of lone-pair electrons, the concentration of free carriers in the system decreases resulting in an increase in resistance despite the structural relaxation towards the crystalline phase.

  13. The metallization of Ge-doped plastics

    International Nuclear Information System (INIS)

    Huser, G.; Recoules, V.; Salin, G.; Galmiche, D.; Ozaki, N.; Miyanishi, K.; Kodama, R.; Sano, T.; Sakawa, Y.

    2013-01-01

    Ge-doped plastics are used in inertial fusion targets. Doped plastics are complex mixtures and the validation of their properties in a broad range of thermodynamic conditions requires an experimental validation. The metallization of plastics appears when shock waves generated by power lasers create pressures around 10 6 bar and temperatures around 10.000 K. The shock front propagating in the plastic becomes reflective. We have performed experiments to test the mathematical models describing the compressibility of such materials. We have compared the Thomas-Fermi model that is implemented in the QEOS formalism (Quotidian Equation of State) with 2 other models: the Sommerfeld metal model and a model that allows the closure of the semi-conducting gap. It appears that the Thomas-Fermi model predicts satisfactorily the compressibility of a mixture compressed at a few 10 6 bars, but over-estimates the average ionisation by a factor up to 10 which leads to an over-estimation of the metallization step

  14. Higgs Candidates in $e^{+}e^{-}$ Interactions at $\\sqrt{s}$ = 206.6 GeV

    CERN Document Server

    Acciarri, M.; Adriani, O.; Aguilar-Benitez, M.; Alcaraz, J.; Alemanni, G.; Allaby, J.; Aloisio, A.; Alviggi, M.G.; Ambrosi, G.; Anderhub, H.; Andreev, Valery P.; Angelescu, T.; Anselmo, F.; Arefev, A.; Azemoon, T.; Aziz, T.; Bagnaia, P.; Bajo, A.; Baksay, L.; Balandras, A.; Baldew, S.V.; Banerjee, S.; Banerjee, Sw.; Barczyk, A.; Barillere, R.; Bartalini, P.; Basile, M.; Batalova, N.; Battiston, R.; Bay, A.; Becattini, F.; Becker, U.; Behner, F.; Bellucci, L.; Berbeco, R.; Berdugo, J.; Berges, P.; Bertucci, B.; Betev, B.L.; Bhattacharya, S.; Biasini, M.; Biland, A.; Blaising, J.J.; Blyth, S.C.; Bobbink, G.J.; Bohm, A.; Boldizsar, L.; Borgia, B.; Bourilkov, D.; Bourquin, M.; Braccini, S.; Branson, J.G.; Brochu, F.; Buffini, A.; Buijs, A.; Burger, J.D.; Burger, W.J.; Cai, X.D.; Capell, M.; Cara Romeo, G.; Carlino, G.; Cartacci, A.M.; Casaus, J.; Castellini, G.; Cavallari, F.; Cavallo, N.; Cecchi, C.; Cerrada, M.; Cesaroni, F.; Chamizo, M.; Chang, Y.H.; Chaturvedi, U.K.; Chemarin, M.; Chen, A.; Chen, G.; Chen, G.M.; Chen, H.F.; Chen, H.S.; Chiefari, G.; Cifarelli, L.; Cindolo, F.; Civinini, C.; Clare, I.; Clare, R.; Coignet, G.; Colino, N.; Costantini, S.; Cotorobai, F.; de la Cruz, B.; Csilling, A.; Cucciarelli, S.; Dai, T.S.; van Dalen, J.A.; D'Alessandro, R.; de Asmundis, R.; Deglon, P.; Degre, A.; Deiters, K.; della Volpe, D.; Delmeire, E.; Denes, P.; DeNotaristefani, F.; De Salvo, A.; Diemoz, M.; Dierckxsens, M.; van Dierendonck, D.; Dionisi, C.; Dittmar, M.; Dominguez, A.; Doria, A.; Dova, M.T.; Duchesneau, D.; Dufournaud, D.; Duinker, P.; Duran, I.; El Mamouni, H.; Engler, A.; Eppling, F.J.; Erne, F.C.; Ewers, A.; Extermann, P.; Fabre, M.; Falagan, M.A.; Falciano, S.; Favara, A.; Fay, J.; Fedin, O.; Felcini, M.; Ferguson, T.; Fesefeldt, H.; Fiandrini, E.; Field, J.H.; Filthaut, F.; Fisher, P.H.; Fisk, I.; Forconi, G.; Freudenreich, K.; Furetta, C.; Galaktionov, Iouri; Ganguli, S.N.; Garcia-Abia, Pablo; Gataullin, M.; Gau, S.S.; Gentile, S.; Gheordanescu, N.; Giagu, S.; Gong, Z.F.; Grenier, Gerald Jean; Grimm, O.; Gruenewald, M.W.; Guida, M.; van Gulik, R.; Gupta, V.K.; Gurtu, A.; Gutay, L.J.; Haas, D.; Hasan, A.; Hatzifotiadou, D.; Hebbeker, T.; Herve, Alain; Hidas, P.; Hirschfelder, J.; Hofer, H.; Holzner, G.; Hoorani, H.; Hou, S.R.; Hu, Y.; Iashvili, I.; Jin, B.N.; Jones, Lawrence W.; de Jong, P.; Josa-Mutuberria, I.; Khan, R.A.; Kafer, D.; Kaur, M.; Kienzle-Focacci, M.N.; Kim, D.; Kim, J.K.; Kirkby, Jasper; Kiss, D.; Kittel, W.; Klimentov, A.; Konig, A.C.; Kopal, M.; Kopp, A.; Koutsenko, V.; Kraber, M.; Kraemer, R.W.; Krenz, W.; Kruger, A.; Kunin, A.; Ladron de Guevara, P.; Laktineh, I.; Landi, G.; Lebeau, M.; Lebedev, A.; Lebrun, P.; Lecomte, P.; Lecoq, P.; Le Coultre, P.; Lee, H.J.; Le Goff, J.M.; Leiste, R.; Levtchenko, P.; Li, C.; Likhoded, S.; Lin, C.H.; Lin, W.T.; Linde, F.L.; Lista, L.; Liu, Z.A.; Lohmann, W.; Longo, E.; Lu, Y.S.; Lubelsmeyer, K.; Luci, C.; Luckey, David; Lugnier, L.; Luminari, L.; Lustermann, W.; Ma, W.G.; Maity, M.; Malgeri, L.; Malinin, A.; Mana, C.; Mangeol, D.; Mans, J.; Marian, G.; Martin, J.P.; Marzano, F.; Mazumdar, K.; McNeil, R.R.; Mele, S.; Merola, L.; Meschini, M.; Metzger, W.J.; von der Mey, M.; Mihul, A.; Milcent, H.; Mirabelli, G.; Mnich, J.; Mohanty, G.B.; Moulik, T.; Muanza, G.S.; Muijs, A.J.M.; Musicar, B.; Musy, M.; Napolitano, M.; Nessi-Tedaldi, F.; Newman, H.; Niessen, T.; Nisati, A.; Kluge, Hannelies; Ofierzynski, R.; Organtini, G.; Oulianov, A.; Palomares, C.; Pandoulas, D.; Paoletti, S.; Paolucci, P.; Paramatti, R.; Park, H.K.; Park, I.H.; Passaleva, G.; Patricelli, S.; Paul, Thomas Cantzon; Pauluzzi, M.; Paus, C.; Pauss, F.; Pedace, M.; Pensotti, S.; Perret-Gallix, D.; Petersen, B.; Piccolo, D.; Pierella, F.; Pieri, M.; Piroue, P.A.; Pistolesi, E.; Plyaskin, V.; Pohl, M.; Pojidaev, V.; Postema, H.; Pothier, J.; Prokofev, D.O.; Prokofev, D.; Quartieri, J.; Rahal-Callot, G.; Rahaman, M.A.; Raics, P.; Raja, N.; Ramelli, R.; Rancoita, P.G.; Ranieri, R.; Raspereza, A.; Raven, G.; Razis, P.; Ren, D.; Rescigno, M.; Reucroft, S.; Riemann, S.; Riles, Keith; Rodin, J.; Roe, B.P.; Romero, L.; Rosca, A.; Rosier-Lees, S.; Roth, Stefan; Rosenbleck, C.; Rubio, J.A.; Ruggiero, G.; Rykaczewski, H.; Saremi, S.; Sarkar, S.; Salicio, J.; Sanchez, E.; Sanders, M.P.; Schafer, C.; Schegelsky, V.; Schmidt-Kaerst, S.; Schmitz, D.; Schopper, H.; Schotanus, D.J.; Schwering, G.; Sciacca, C.; Seganti, A.; Servoli, L.; Shevchenko, S.; Shivarov, N.; Shoutko, V.; Shumilov, E.; Shvorob, A.; Siedenburg, T.; Son, D.; Smith, B.; Spillantini, P.; Steuer, M.; Stickland, D.P.; Stone, A.; Stoyanov, B.; Straessner, A.; Sudhakar, K.; Sultanov, G.; Sun, L.Z.; Sushkov, S.; Suter, H.; Swain, J.D.; Szillasi, Z.; Sztaricskai, T.; Tang, X.W.; Tauscher, L.; Taylor, L.; Tellili, B.; Timmermans, Charles; Ting, Samuel C.C.; Ting, S.M.; Tonwar, S.C.; Toth, J.; Tully, C.; Tung, K.L.; Uchida, Y.; Ulbricht, J.; Valente, E.; Vesztergombi, G.; Vetlitsky, I.; Vicinanza, D.; Viertel, G.; Villa, S.; Vivargent, M.; Vlachos, S.; Vodopianov, I.; Vogel, H.; Vogt, H.; Vorobev, I.; Vorobov, A.A.; Vorvolakos, A.; Wadhwa, M.; Wallraff, W.; Wang, M.; Wang, X.L.; Wang, Z.M.; Weber, A.; Weber, M.; Wienemann, P.; Wilkens, H.; Wu, S.X.; Wynhoff, S.; Xia, L.; Xu, Z.Z.; Yamamoto, J.; Yang, B.Z.; Yang, C.G.; Yang, H.J.; Yang, M.; Ye, J.B.; Yeh, S.C.; Zalite, A.; Zalite, Yu.; Zhang, Z.P.; Zhu, G.Y.; Zhu, R.Y.; Zichichi, A.; Zilizi, G.; Zimmermann, B.; Zoller, M.

    2000-01-01

    In a search for the Standard Model Higgs boson, carried out on 212.5 pb-1 of data collected by the L3 detector at the highest LEP centre-of-mass energies, including 116.5 pb-1 above root(s) = 206GeV, an excess of candidates for the process e+e- -> Z* -> HZ is found for Higgs masses near 114.5GeV. We present an analysis of our data and the characteristics of our strongest candidates.

  15. DisGeNET-RDF: harnessing the innovative power of the Semantic Web to explore the genetic basis of diseases.

    Science.gov (United States)

    Queralt-Rosinach, Núria; Piñero, Janet; Bravo, Àlex; Sanz, Ferran; Furlong, Laura I

    2016-07-15

    DisGeNET-RDF makes available knowledge on the genetic basis of human diseases in the Semantic Web. Gene-disease associations (GDAs) and their provenance metadata are published as human-readable and machine-processable web resources. The information on GDAs included in DisGeNET-RDF is interlinked to other biomedical databases to support the development of bioinformatics approaches for translational research through evidence-based exploitation of a rich and fully interconnected linked open data. http://rdf.disgenet.org/ support@disgenet.org. © The Author 2016. Published by Oxford University Press.

  16. K vacancy production in collisions of 63 MeV Cu ions with Ge and Ag atoms

    International Nuclear Information System (INIS)

    Frank, W.; Jaracz, R.; Kaun, K.-H.; Rudiger, J.; Stachura, Z.

    1980-01-01

    The mechanism of K-shell vacancy production is studied in t in an X-ray-scattered ion coincidence experiment with 1 MeV/a.m.u. 63 Cu 4+ ion incident onto natural Ge and Ag targets. The impact parameter dependent K-shell vacancy production probability measured in the experiment is interpreted in terms of the rotational coupling and the statistical models. The dependence of the vacancy sharing process in the Cu-Ge collision system on the impact parameter is obtained and compared with the predictions of the Briggs-Myerhof-Demkov model

  17. RBS characterization of the deposition of very thin SiGe/SiO2 multilayers by LPCVD

    International Nuclear Information System (INIS)

    Munoz-Martin, A.; Climent-Font, A.; Rodriguez, A.; Sangrador, J.; Rodriguez, T.

    2005-01-01

    Multilayer structures consisting of several alternated layers of SiGe and SiO 2 with thickness ranging from 2 or Si as well as the deposition of SiO 2 on Si show negligible incubation times. The deposition of SiO 2 on SiGe, however, exhibits an incubation time of several minutes, which would be related to the oxidation of the surface necessary for the SiO 2 deposition to start. In all cases the film thickness increases linearly with deposition time, thus allowing the growth rates to be determined. These data allow the deposition process of these very thin layers to be accurately controlled

  18. Determination of adiabatic temperature change in MnFe(P,Ge) compounds with pulse-field method

    International Nuclear Information System (INIS)

    Trung, N T; Tegus, O; Cam Thanh, D T; Buschow, K H J; Brueck, E; Klaasse, J C P

    2010-01-01

    Fast magnetic measurements performed by means of a 20 T pulse-field magnet provide a good approach for directly monitoring the magnetocaloric effect of the MnFe(P,Ge) compounds. Based on the comparison of magnetization curves obtained either in an adiabatic or isothermal process, we propose that the method introduced by Levitin et al is applicable to determine the adiabatic temperature change for an equivalent field change in first-order magnetic transition materials. More strikingly, experimental results confirm that the first-order nature of the transition in MnFe(P,Ge) alloys is not a limiting factor to the operation frequency of a magnetic refrigerator.

  19. Antimony segregation in Ge and formation of n-type selectively doped Ge films in molecular beam epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Yurasov, D. V., E-mail: Inquisitor@ipm.sci-nnov.ru; Antonov, A. V.; Drozdov, M. N.; Schmagin, V. B.; Novikov, A. V. [Institute for Physics of Microstructures, Russian Academy of Sciences, GSP-105, 603950 Nizhny Novgorod (Russian Federation); Lobachevsky State University of Nizhni Novgorod, 23 Prospekt Gagarina, 603950 Nizhny Novgorod (Russian Federation); Spirin, K. E. [Institute for Physics of Microstructures, Russian Academy of Sciences, GSP-105, 603950 Nizhny Novgorod (Russian Federation)

    2015-10-14

    Antimony segregation in Ge(001) films grown by molecular beam epitaxy was studied. A quantitative dependence of the Sb segregation ratio in Ge on growth temperature was revealed experimentally and modeled theoretically taking into account both the terrace-mediated and step-edge-mediated segregation mechanisms. A nearly 5-orders-of-magnitude increase in the Sb segregation ratio in a relatively small temperature range of 180–350 °C was obtained, which allowed to form Ge:Sb doped layers with abrupt boundaries and high crystalline quality using the temperature switching method that was proposed earlier for Si-based structures. This technique was employed for fabrication of different kinds of n-type Ge structures which can be useful for practical applications like heavily doped n{sup +}-Ge films or δ-doped layers. Estimation of the doping profiles sharpness yielded the values of 2–5 nm per decade for the concentration gradient at the leading edge and 2–3 nm for the full-width-half-maximum of the Ge:Sb δ-layers. Electrical characterization of grown Ge:Sb structures revealed nearly full electrical activation of Sb atoms and the two-dimensional nature of charge carrier transport in δ-layers.

  20. Single ferromagnetic fluctuations in UCoGe revealed by 73Ge- and 59Co-NMR studies

    Science.gov (United States)

    Manago, Masahiro; Ishida, Kenji; Aoki, Dai

    2018-02-01

    73Ge and 59Co nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) measurements have been performed on a 73Ge-enriched single-crystalline sample of the ferromagnetic superconductor UCoGe in the paramagnetic state. The 73Ge NQR parameters deduced from NQR and NMR are close to those of another isostructural ferromagnetic superconductor URhGe. The Knight shifts of the Ge and Co sites are well scaled to each other when the magnetic field is parallel to the b or c axis. The hyperfine coupling constants of Ge are estimated to be close to those of Co. The large difference of spin susceptibilities between the a and b axes could lead to the different response of the superconductivity and ferromagnetism with the field parallel to these directions. The temperature dependence of the nuclear spin-lattice relaxation rates 1 /T1 at the two sites is similar to each other above 5 K. These results indicate that the itinerant U-5 f electrons are responsible for the ferromagnetism in this compound, consistent with previous studies. The similarities and differences in the three ferromagnetic superconductors are discussed.

  1. 3D hollow framework of GeOx with ultrathin shell for improved anode performance in lithium-ion batteries

    International Nuclear Information System (INIS)

    Fang, Zhen; Qiang, Tingting; Fang, Jiaxin; Song, Yixuan; Ma, Qiuyang; Ye, Ming; Qiang, Feiqiang; Geng, Baoyou

    2015-01-01

    Highlights: • 3D hollow framework of GeO x was synthesized using hydrothermal procedure. • The obtained GeO x 3D hollow framework has large surface area and porous thin shell. • The structure improved the cycle and rate performances. - Abstract: In this paper, 3D hollow framework of GeO x is synthesized using a bubble-template hydrothermal procedure. The as-obtained hollow structure exhibits excellent cycling performance and rate capability in comparison with GeO x nanoparticles when used as an anode material in lithium ion batteries. The GeO x 3D hollow framework shows a high capacity of up to 1480 mAh·g −1 and 1109 mAh·g −1 at 80 mA·g −1 and 1600 mA·g −1 current density, respectively. The excellent lithium storage performance can be attributed to the unique 3D hollow framework. The framework not only acts as the buffer layer to alleviate the strain during lithiation, but also facilitates the electron transfer during the charge/discharge processes

  2. Ag-NP@Ge-nanotaper/Si-micropillar ordered arrays as ultrasensitive and uniform surface enhanced Raman scattering substrates.

    Science.gov (United States)

    Liu, Jing; Meng, Guowen; Li, Zhongbo; Huang, Zhulin; Li, Xiangdong

    2015-11-21

    Surface-enhanced Raman scattering (SERS) is considered to be an excellent candidate for analytical detection schemes, because of its molecular specificity, rapid response and high sensitivity. Here, SERS-substrates of Ag-nanoparticle (Ag-NP) decorated Ge-nanotapers grafted on hexagonally ordered Si-micropillar (denoted as Ag-NP@Ge-nanotaper/Si-micropillar) arrays are fabricated via a combinatorial process of two-step etching to achieve hexagonal Si-micropillar arrays, chemical vapor deposition of flocky Ge-nanotapers on each Si-micropillar and decoration of Ag-NPs onto the Ge-nanotapers through galvanic displacement. With high density three-dimensional (3D) "hot spots" created from the large quantities of the neighboring Ag-NPs and large-scale uniform morphology, the hierarchical Ag-NP@Ge-nanotaper/Si-micropillar arrays exhibit strong and reproducible SERS activity. Using our hierarchical 3D SERS-substrates, both methyl parathion (a commonly used pesticide) and PCB-2 (one congener of highly toxic polychlorinated biphenyls) with concentrations down to 10(-7) M and 10(-5) M have been detected respectively, showing great potential in SERS-based rapid trace-level detection of toxic organic pollutants in the environment.

  3. Coulomb-nuclear interference with 6Li: Isospin character of the 21+ excitation in 70,72,74Ge

    International Nuclear Information System (INIS)

    Barbosa, M.D.L.; Borello-Lewin, T.; Horodynski-Matsushigue, L.B.; Duarte, J.L.M.; Rodrigues, C.L.; Rodrigues, M.R.D.; Ukita, G.M.

    2005-01-01

    Ratios of B(E2) to B(IS2), that is, of the reduced quadrupole transition probabilities related, respectively, to charge and mass were e