WorldWideScience

Sample records for included thermal annealing

  1. Morphological, thermal and annealed microhardness ...

    Indian Academy of Sciences (India)

    Unknown

    blended with sugarcane bagasse which showed good me- chanical properties when investigated by SEM, thermal gravimetric analysis (TGA), DSC and tensile testing (Chiel- lini et al 2001). An increase in the engineering yield stress was observed, with a decline in tensile impact strength. With DSC on annealing, a small ...

  2. Morphological, thermal and annealed microhardness ...

    Indian Academy of Sciences (India)

    The present paper reports the preparation of full IPNs of gelatin and polyacrylonitrile. Various compositions of gluteraldehyde crosslinked gelatin and N,N′-methylene-bis-acrylamide crosslinked PAN were characterized by SEM and DSC techniques. The IPNs were also thermally pretreated by the annealing process.

  3. Thermal annealing of tilted fiber Bragg gratings

    Science.gov (United States)

    González-Vila, Á.; Rodríguez-Cobo, L.; Mégret, P.; Caucheteur, C.; López-Higuera, J. M.

    2016-05-01

    We report a practical study of the thermal decay of cladding mode resonances in tilted fiber Bragg gratings, establishing an analogy with the "power law" evolution previously observed on uniform gratings. We examine how this process contributes to a great thermal stability, even improving it by means of a second cycle slightly increasing the annealing temperature. In addition, we show an improvement of the grating spectrum after annealing, with respect to the one just after inscription, which suggests the application of this method to be employed to improve saturation issues during the photo-inscription process.

  4. Thermal annealing in neutron-irradiated tribromobenzenes

    DEFF Research Database (Denmark)

    Siekierska, K.E.; Halpern, A.; Maddock, A. G.

    1968-01-01

    The distribution of 82Br among various products in neutron-irradiated isomers of tribromobenzene has been investigated, and the effect of thermal annealing examined. Reversed-phase partition chromatography was employed for the determination of radioactive organic products, and atomic bromine...

  5. Response of neutron-irradiated RPV steels to thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Iskander, S.K.; Sokolov, M.A.; Nanstad, R.K.

    1997-03-01

    One of the options to mitigate the effects of irradiation on reactor pressure vessels (RPVs) is to thermally anneal them to restore the fracture toughness properties that have been degraded by neutron irradiation. This paper summarizes experimental results of work performed at the Oak Ridge National Laboratory (ORNL) to study the annealing response of several irradiated RPV steels.

  6. Novel thermal annealing methodology for permanent tuning polymer optical fiber Bragg gratings to longer wavelengths.

    Science.gov (United States)

    Pospori, A; Marques, C A F; Sagias, G; Lamela-Rivera, H; Webb, D J

    2018-01-22

    The Bragg wavelength of a polymer optical fiber Bragg grating can be permanently shifted by utilizing the thermal annealing method. In all the reported fiber annealing cases, the authors were able to tune the Bragg wavelength only to shorter wavelengths, since the polymer fiber shrinks in length during the annealing process. This article demonstrates a novel thermal annealing methodology for permanently tuning polymer optical fiber Bragg gratings to any desirable spectral position, including longer wavelengths. Stretching the polymer optical fiber during the annealing process, the period of Bragg grating, which is directly related with the Bragg wavelength, can become permanently longer. The methodology presented in this article can be used to multiplex polymer optical fiber Bragg gratings at any desirable spectral position utilizing only one phase-mask for their photo-inscription, reducing thus their fabrication cost in an industrial setting.

  7. Far-infrared spectroscopy of thermally annealed tungsten silicide films

    International Nuclear Information System (INIS)

    Amiotti, M.; Borghesi, A.; Guizzetti, G.; Nava, F.; Santoro, G.

    1991-01-01

    The far-infrared transmittance spectrum of tungsten silicide has been observed for the first time. WSi 2 polycrystalline films were prepared by coevaporation and chemical-vapour deposition on silicon wafers, and subsequently thermally annealed at different temperatures. The observed structures are interpreted, on the basis of the symmetry properties of the crystal, such as infrared-active vibrational modes. Moreover, the marked lineshape dependence on annealing temperature enables this technique to analyse the formation of the solid silicide phases

  8. Rapid Thermal annealing of silicon layers amorphized by ion implantation

    International Nuclear Information System (INIS)

    Hasenack, C.M.

    1986-01-01

    The recrystallization behavior and the supression mechanisms of the residual defects of silicon layers amorphized by ion implantation, were investigated. The samples were annealed with the aid of a rapid thermal annealing (RTA) system at temperature range from 850 to 1200 0 C, and annealing time up to 120 s. Random and aligned Rutherford backscattering spectroscopy were used to analyse the samples. Similarities in the recrystallization behavior for layers implanted with ions of the same chemical groups such as As or Sb; Ge, Sn or Pb, In or Ga, are observed. The results show that the effective supression of resisual defects of the recrystallired layers is vinculated to the redistribution of impurities via thermal diffusion. (author) [pt

  9. Thermal annealing of femtosecond laser written structures in silica glass

    NARCIS (Netherlands)

    Witcher, J.J.; Reichman, W.B.; Fletcher, L.B.; Troy, N.W.; Krol, D.M.

    2013-01-01

    We have investigated the thermal stability of femtosecond laser modification inside fused silica. Raman and FL spectroscopy show that fs-laser induced non-bridging oxygen hole center (NBOHC) defects completely disappear at 300 °C, whereas changes in Si-O ring structures only anneal out after heat

  10. Thermal annealing and ionic abrasion in ZnTe

    International Nuclear Information System (INIS)

    Bensahel, D.

    1975-01-01

    Thermal annealing of the ZnTe crystal is studied first in order to obtain information on the aspect of the penetration profile. Ionic abrasion is then investigated to find out whether it produces the same effects as ionic implantation, especially for luminescence [fr

  11. Doped ZnO nanowires obtained by thermal annealing.

    Science.gov (United States)

    Shan, C X; Liu, Z; Wong, C C; Hark, S K

    2007-02-01

    Doped ZnO nanowires were prepared in a very simple and inexpensive thermal annealing method using ZnSe nanowires as a precursor. As doped, P doped, and As/P codoped ZnO nanowires were obtained in this method. X-ray diffraction shows that the zincblende ZnSe nanowires were converted to doped wurtzite ZnO nanowires. The incorporation of the dopants was confirmed by energy dispersive X-ray spectroscopy. The doping concentration could be adjusted by changing the annealing temperature and duration. Scanning electron microscopy indicated that the morphology of the ZnSe nanowires was essentially retained after the annealing and doping process. Photoluminescence spectroscopy also verified the incorporation of the dopants into the nanowires.

  12. Optimized Laser Thermal Annealing on Germanium for High Dopant Activation and Low Leakage Current

    DEFF Research Database (Denmark)

    Shayesteh, Maryam; O' Connell, Dan; Gity, Farzan

    2014-01-01

    In this paper, state-of-the-art laser thermal annealing is used to fabricate Ge diodes. We compared the effect of laser thermal annealing (LTA) and rapid thermal annealing (RTA) on dopant activation and electrical properties of phosphorus and Arsenic-doped n +/p junctions. Using LTA, high carrier...

  13. Electro-optical characteristics of indium tin oxide (ITO) films: effect of thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Morgan, D.V.; Salehi, A.; Aliyu, Y.H.; Bunce, R.W. [University of Wales College of Cardiff (United Kingdom). School of Electrical, Electronics and System Engineering

    1996-02-01

    The effect of thermal annealing on the electrical and optical characteristics of ITO films prepared by reactive sputtering and thermal evaporation have been studied. The effect of the thermal annealing is to improve the conductivity and the optical transmission in the shorter wavelength region. The conductivity of the films increases with annealing temperature, this behaviour is associated with grain growth in the film. (author)

  14. Dating thermal events at Cerro Prieto using fission track annealing

    Energy Technology Data Exchange (ETDEWEB)

    Sanford, S.J.; Elders, W..

    1981-01-01

    Data from laboratory experiments and geologic fading studies were compiled from published sources to produce lines of iso-annealing for apatite in time-temperature space. Fission track ages were calculated for samples from two wells at Cerro Prieto, one with an apparently simple and one with an apparently complex thermal history. Temperatures were estimated by empirical vitrinite reflectance geothermometry, fluid inclusion homogenization and oxygen isotope equilibrium. These estimates were compared with logs of measured borehole temperatures.

  15. 10 CFR 50.66 - Requirements for thermal annealing of the reactor pressure vessel.

    Science.gov (United States)

    2010-01-01

    ... Requirements for thermal annealing of the reactor pressure vessel. (a) For those light water nuclear power... operating plan must include: (i) A detailed description of the pressure vessel and all structures and... For those cases where materials are removed from the beltline of the pressure vessel, the stress...

  16. Positron annihilation studies on reactor irradiated and thermal annealed ferrocene

    International Nuclear Information System (INIS)

    Marques Netto, A.; Carvalho, R.S.; Magalhaes, W.F.; Sinisterra, R.D.

    1996-01-01

    Retention and thermal annealing following (n, γ) reaction in solid ferrocene, Fe(C 5 H 5 ) 2 , were studied by positron annihilation lifetime spectroscopy (PAL). Positronium (Ps) formation was observed in the non-irradiated compound with a probability or intensity (I 3 ) of 30%. Upon irradiation of the compound with thermal neutrons in a nuclear reactor, I 3 decreases with increasing irradiation time. Thermal treatment again increases I 3 values from 16% to 25%, revealing an important proportion of molecular reformation without variation of the ortho-positronium lifetime (τ 3 ). These results point out the major influence of the electronic structure as determining the Ps yields in the pure complex. In the irradiated and non irradiated complexes the results are satisfactorily explained on the basis of the spur model. (orig.)

  17. Enabling Inkjet Printed Graphene for Ion Selective Electrodes with Postprint Thermal Annealing.

    Science.gov (United States)

    He, Qing; Das, Suprem R; Garland, Nathaniel T; Jing, Dapeng; Hondred, John A; Cargill, Allison A; Ding, Shaowei; Karunakaran, Chandran; Claussen, Jonathan C

    2017-04-12

    Inkjet printed graphene (IPG) has recently shown tremendous promise in reducing the cost and complexity of graphene circuit fabrication. Herein we demonstrate, for the first time, the fabrication of an ion selective electrode (ISE) with IPG. A thermal annealing process in a nitrogen ambient environment converts the IPG into a highly conductive electrode (sheet resistance changes from 52.8 ± 7.4 MΩ/□ for unannealed graphene to 172.7 ± 33.3 Ω/□ for graphene annealed at 950 °C). Raman spectroscopy and field emission scanning electron microscopy (FESEM) analysis reveals that the printed graphene flakes begin to smooth at an annealing temperature of 500 °C and then become more porous and more electrically conductive when annealed at temperatures of 650 °C and above. The resultant thermally annealed, IPG electrodes are converted into potassium ISEs via functionalization with a poly(vinyl chloride) (PVC) membrane and valinomycin ionophore. The developed potassium ISE displays a wide linear sensing range (0.01-100 mM), a low detection limit (7 μM), minimal drift (8.6 × 10 -6 V/s), and a negligible interference during electrochemical potassium sensing against the backdrop of interfering ions [i.e., sodium (Na), magnesium (Mg), and calcium (Ca)] and artificial eccrine perspiration. Thus, the IPG ISE shows potential for potassium detection in a wide variety of human fluids including plasma, serum, and sweat.

  18. Thermal annealing of natural, radiation-damaged pyrochlore

    Energy Technology Data Exchange (ETDEWEB)

    Zietlow, Peter; Beirau, Tobias; Mihailova, Boriana; Groat, Lee A.; Chudy, Thomas; Shelyug, Anna; Navrotsky, Alexandra; Ewing, Rodney C.; Schlüter, Jochen; Škoda, Radek; Bismayer, Ulrich

    2017-01-01

    Abstract

    Radiation damage in minerals is caused by the α-decay of incorporated radionuclides, such as U and Th and their decay products. The effect of thermal annealing (400–1000 K) on radiation-damaged pyrochlores has been investigated by Raman scattering, X-ray powder diffraction (XRD), and combined differential scanning calorimetry/thermogravimetry (DSC/TG). The analysis of three natural radiation-damaged pyrochlore samples from Miass/Russia [6.4 wt% Th, 23.1·10

  19. Rapid magnetic hardening by rapid thermal annealing in NdFeB-based nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Chu, K.-T.; Jin, Z Q; Chakka, Vamsi M; Liu, J P [Department of Physics, University of Texas at Arlington, Arlington, TX 76019 (United States)

    2005-11-21

    A systematic study of heat treatments and magnetic hardening of NdFeB-based melt-spun nanocomposite ribbons have been carried out. Comparison was made between samples treated by rapid thermal annealing and by conventional furnace annealing. Heating rates up to 200 K s{sup -1} were adopted in the rapid thermal processing. It was observed that magnetic hardening can be realized in an annealing time as short as 1 s. Coercivity of 10.2 kOe in the nanocomposites has been obtained by rapid thermal annealing for 1 s, and prolonged annealing did not give any increase in coercivity. Detailed results on the effects of annealing time, temperature and heating rate have been obtained. The dependence of magnetic properties on the annealing parameters has been investigated. Structural characterization revealed that there is a close correlation between magnetic hardening and nanostructured morphology. The coercivity mechanism was also studied by analysing the magnetization minor loops.

  20. Advanced phase change composite by thermally annealed defect-free graphene for thermal energy storage.

    Science.gov (United States)

    Xin, Guoqing; Sun, Hongtao; Scott, Spencer Michael; Yao, Tiankai; Lu, Fengyuan; Shao, Dali; Hu, Tao; Wang, Gongkai; Ran, Guang; Lian, Jie

    2014-09-10

    Organic phase change materials (PCMs) have been utilized as latent heat energy storage and release media for effective thermal management. A major challenge exists for organic PCMs in which their low thermal conductivity leads to a slow transient temperature response and reduced heat transfer efficiency. In this work, 2D thermally annealed defect-free graphene sheets (GSs) can be obtained upon high temperature annealing in removing defects and oxygen functional groups. As a result of greatly reduced phonon scattering centers for thermal transport, the incorporation of ultralight weight and defect free graphene applied as nanoscale additives into a phase change composite (PCC) drastically improve thermal conductivity and meanwhile minimize the reduction of heat of fusion. A high thermal conductivity of the defect-free graphene-PCC can be achieved up to 3.55 W/(m K) at a 10 wt % graphene loading. This represents an enhancement of over 600% as compared to pristine graphene-PCC without annealing at a comparable loading, and a 16-fold enhancement than the pure PCM (1-octadecanol). The defect-free graphene-PCC displays rapid temperature response and superior heat transfer capability as compared to the pristine graphene-PCC or pure PCM, enabling transformational thermal energy storage and management.

  1. Enhanced bulk heterojunction devices prepared by thermal and solvent vapor annealing processes

    Science.gov (United States)

    Forrest, Stephen R.; Thompson, Mark E.; Wei, Guodan; Wang, Siyi

    2017-09-19

    A method of preparing a bulk heterojunction organic photovoltaic cell through combinations of thermal and solvent vapor annealing are described. Bulk heterojunction films may prepared by known methods such as spin coating, and then exposed to one or more vaporized solvents and thermally annealed in an effort to enhance the crystalline nature of the photoactive materials.

  2. Thermal annealing of natural, radiation-damaged pyrochlore

    Energy Technology Data Exchange (ETDEWEB)

    Zietlow, Peter; Mihailova, Boriana [Hamburg Univ. (Germany). Dept. of Earth Sciences; Beirau, Tobias [Hamburg Univ. (Germany). Dept. of Earth Sciences; Stanford Univ., CA (United States). Dept. of Geological Sciences; and others

    2017-03-01

    Radiation damage in minerals is caused by the α-decay of incorporated radionuclides, such as U and Th and their decay products. The effect of thermal annealing (400-1000 K) on radiation-damaged pyrochlores has been investigated by Raman scattering, X-ray powder diffraction (XRD), and combined differential scanning calorimetry/thermogravimetry (DSC/TG). The analysis of three natural radiation-damaged pyrochlore samples from Miass/Russia [6.4 wt% Th, 23.1.10{sup 18} α-decay events per gram (dpg)], Panda Hill/Tanzania (1.6 wt% Th, 1.6.10{sup 18} dpg), and Blue River/Canada (10.5 wt% U, 115.4.10{sup 18} dpg), are compared with a crystalline reference pyrochlore from Schelingen (Germany). The type of structural recovery depends on the initial degree of radiation damage (Panda Hill 28%, Blue River 85% and Miass 100% according to XRD), as the recrystallization temperature increases with increasing degree of amorphization. Raman spectra indicate reordering on the local scale during annealing-induced recrystallization. As Raman modes around 800 cm{sup -1} are sensitive to radiation damage (M. T. Vandenborre, E. Husson, Comparison of the force field in various pyrochlore families. I. The A{sub 2}B{sub 2}O{sub 7} oxides. J. Solid State Chem. 1983, 50, 362, S. Moll, G. Sattonnay, L. Thome, J. Jagielski, C. Decorse, P. Simon, I. Monnet, W. J. Weber, Irradiation damage in Gd{sub 2}Ti{sub 2}O{sub 7} single crystals: Ballistic versus ionization processes. Phys. Rev. 2011, 84, 64115.), the degree of local order was deduced from the ratio of the integrated intensities of the sum of the Raman bands between 605 and 680 cm{sup -1} divided by the sum of the integrated intensities of the bands between 810 and 860 cm{sup -1}. The most radiation damaged pyrochlore (Miass) shows an abrupt recovery of both, its short- (Raman) and long-range order (X-ray) between 800 and 850 K, while the weakly damaged pyrochlore (Panda Hill) begins to recover at considerably lower temperatures (near 500 K

  3. Effect of thermal annealing on properties of polycrystalline ZnO thin films

    Science.gov (United States)

    Gritsenko, L. V.; Abdullin, Kh. A.; Gabdullin, M. T.; Kalkozova, Zh. K.; Kumekov, S. E.; Mukash, Zh. O.; Sazonov, A. Yu.; Terukov, E. I.

    2017-01-01

    Electrical properties (density, carriers mobility, resistivity), optical absorption and photoluminescence spectra of ZnO, grown by MOCVD and hydrothermal methods, have been investigated depending on the annealing and treatment modes in a hydrogen plasma. It has been shown that the electrical and photoluminescent (PL) properties of ZnO are strongly dependent on gas atmosphere during annealing. The annealing in oxygen atmosphere causes a sharp drop of carrier mobility and films conductivity due to the absorption of oxygen on grain boundaries. The process of ZnO electrical properties recovery by the thermal annealing in inert atmosphere (nitrogen), in oil (2×10-2 mbar) and oil-free (1×10-5 mbar) vacuum has been investigated. The hydrogen plasma treatment influence on the intensity of near-band-gap emission (NBE) has been studied. The effect of annealing and subsequent plasma treatment on PL intensity depends on the gas atmosphere of preliminary thermal annealing.

  4. Effect of thermal annealing on the surface properties of electrospun polymer fibers.

    Science.gov (United States)

    Chen, Jiun-Tai; Chen, Wan-Ling; Fan, Ping-Wen; Yao, I-Chun

    2014-02-01

    Electrospun polymer fibers are gaining importance because of their unique properties and applications in areas such as drug delivery, catalysis, or tissue engineering. Most studies to control the morphology and properties of electrospun polymer fibers focus on changing the electrospinning conditions. The effects of post-treatment processes on the morphology and properties of electrospun polymer fibers, however, are little studied. Here, the effect of thermal annealing on the surface properties of electrospun polymer fibers is investigated. Poly(methyl methacrylate) and polystyrene fibers are fist prepared by electrospinning, followed by thermal annealing processes. Upon thermal annealing, the surface roughness of the electrospun polymer fibers decreases. The driving force of the smoothing process is the minimization of the interfacial energy between polymer fibers and air. The water contact angles of the annealed polymer fibers also decrease with the annealing time. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. The effect of thermal annealing on the properties of thin alumina films prepared by low pressure MOCVD

    NARCIS (Netherlands)

    Haanappel, V.A.C.; Haanappel, V.A.C.; van de Vendel, D.; van Corbach, H.D.; Fransen, T.; Gellings, P.J.

    1995-01-01

    Thin amorphous alumina films were prepared on stainless steel, type AISI 304, by low pressure metal-organic chemical vapour deposition. The effect of thermal annealing in nitrogen (for 2, 4 and 17 h at 600, 700 and 800 °C) on the film properties, including the protection of the underlying substrate

  6. Behavior of oxygen in zinc oxide films through thermal annealing and its effect on sheet resistance

    International Nuclear Information System (INIS)

    Hiramatsu, Takahiro; Furuta, Mamoru; Matsuda, Tokiyoshi; Li, Chaoyang; Hirao, Takashi

    2011-01-01

    Behavior of oxygen in sputtering deposited ZnO films through thermal annealing and its effect on sheet resistance of the films were investigated. The crystallinities of the ZnO film were improved by post-deposition annealing in vacuum. However, the sheet resistance of ZnO film was dramatically decreased after post-deposition annealing in vacuum at more than 300 deg. C, while O 2 desorbed from the film. The oxygen vacancies which acted as donors were formed by the thermal annealing in vacuum. The sheet resistance of the films was recovered by annealing in oxygen ambient. In this paper, 18 O 2 gas as an oxygen isotope was used as the annealing ambient in order to distinguish from 16 O, which was constituent atom of the ZnO films. SIMS analysis revealed that 18 O diffused into the ZnO film from the top surface by 18 O 2 annealing. Therefore oxygen vacancies formed by the post-deposition annealing in vacuum could be compensated by the annealing in oxygen ambient.

  7. Defect annealing and thermal desorption of deuterium in low dose HFIR neutron-irradiated tungsten

    Science.gov (United States)

    Shimada, Masashi; Hara, Masanori; Otsuka, Teppei; Oya, Yasuhisa; Hatano, Yuji

    2015-08-01

    Three tungsten samples irradiated at High Flux Isotope Reactor at Oak Ridge National Laboratory were exposed to deuterium plasma (ion fluence of 1 × 1026 m-2) at three different temperatures (100, 200, and 500 °C) in Tritium Plasma Experiment at Idaho National Laboratory. Subsequently, thermal desorption spectroscopy was performed with a ramp rate of 10 °C min-1 up to 900 °C, and the samples were annealed at 900 °C for 0.5 h. These procedures were repeated three times to uncover defect-annealing effects on deuterium retention. The results show that deuterium retention decreases approximately 70% for at 500 °C after each annealing, and radiation damages were not annealed out completely even after the 3rd annealing. TMAP modeling revealed the trap concentration decreases approximately 80% after each annealing at 900 °C for 0.5 h.

  8. Thermally and Electrically Conductive Nanopapers from Reduced Graphene Oxide: Effect of Nanoflakes Thermal Annealing on the Film Structure and Properties.

    Science.gov (United States)

    Bernal, M Mar; Tortello, Mauro; Colonna, Samuele; Saracco, Guido; Fina, Alberto

    2017-12-05

    In this study, we report a novel strategy to prepare graphene nanopapers from direct vacuum filtration. Instead of the conventional method, i.e., thermal annealing nanopapers at extremely high temperatures prepared from graphene oxide (GO) or partially reduced GO, we fabricate our graphene nanopapers directly from suspensions of fully reduced graphene oxide (RGO), obtained after RGO and thermal annealing at 1700 °C in vacuum. By using this approach, we studied the effect of thermal annealing on the physical properties of the macroscopic graphene-based papers. Indeed, we demonstrated that the enhancement of the thermal and electrical properties of graphene nanopapers prepared from annealed RGO is strongly influenced by the absence of oxygen functionalities and the morphology of the nanoflakes. Hence, our methodology can be considered as a valid alternative to the classical approach.

  9. Thermalization, Freeze-out, and Noise: Deciphering Experimental Quantum Annealers

    Science.gov (United States)

    Marshall, Jeffrey; Rieffel, Eleanor G.; Hen, Itay

    2017-12-01

    By contrasting the performance of two quantum annealers operating at different temperatures, we address recent questions related to the role of temperature in these devices and their function as "Boltzmann samplers." Using a method to reliably calculate the degeneracies of the energy levels of large-scale spin-glass instances, we are able to estimate the instance-dependent effective temperature from the output of annealing runs. Our results corroborate the "freeze-out" picture which posits two regimes, one in which the final state corresponds to a Boltzmann distribution of the final Hamiltonian with a well-defined "effective temperature" determined at a freeze-out point late in the annealing schedule, and another regime in which such a distribution is not necessarily expected. We find that the output distributions of the annealers do not, in general, correspond to a classical Boltzmann distribution for the final Hamiltonian. We also find that the effective temperatures at different programing cycles fluctuate greatly, with the effect worsening with problem size. We discuss the implications of our results for the design of future quantum annealers to act as more-effective Boltzmann samplers and for the programing of such annealers.

  10. Sintering Characteristics of Multilayered Thermal Barrier Coatings Under Thermal Gradient and Isothermal High Temperature Annealing Conditions

    Science.gov (United States)

    Rai, Amarendra K.; Schmitt, Michael P.; Bhattacharya, Rabi; Zhu, Dongming; Wolfe, Douglas E.

    2014-01-01

    Pyrochlore oxides have most of the relevant attributes for use as next generation thermal barrier coatings such as phase stability, low sintering kinetics and low thermal conductivity. One of the issues with the pyrochlore oxides is their lower toughness and therefore higher erosion rate compared to the current state-of-the-art TBC material, yttria (6 to 8 wt%) stabilized zirconia (YSZ). In this work, sintering characteristics were investigated for novel multilayered coating consisted of alternating layers of pyrochlore oxide viz Gd2Zr2O7 and t' low k (rare earth oxide doped YSZ). Thermal gradient and isothermal high temperature (1316 C) annealing conditions were used to investigate sintering and cracking in these coatings. The results are then compared with that of relevant monolayered coatings and a baseline YSZ coating.

  11. Thermal annealing of waveguides formed by ion implantation of silica-on-si

    International Nuclear Information System (INIS)

    Johnson, C.M.; Ridgway, M.C.; Simpson, P.J.

    1998-01-01

    Full text: Buried channel waveguides were fabricated by ion implantation of PECVD-grown silica-on-Si. Post-implantation annealing was observed to have a significant influence on waveguide loss as measured at both 1.3 and 1.55 nm. Waveguide loss decreased abruptly from an as-implanted value of ∼1 dB/cm to ∼0.15 dB/cm following a 500 deg C/1 hr annealing cycle. However, annealing at greater temperatures (600 deg C) yielded a loss value comparable to the as implanted result (∼1dB/cm). This paper will address the factors that potentially influenced the observed loss behaviour which included thermally-induced changes to density and refractive index, precipitation of the implanted ions (Si) and mode profile spreading and subsequent interaction with the waveguide surface. Using surface profilometry and variable-energy positron spectroscopy, no significant density or structural changes were observed over the temperature range of 400-600deg C. The refractive index exhibited comparable behaviour as measured with prism coupling. The potential influence of precipitation was determined by comparing Si implantation with dual Si and O implantation, the latter with a dose ratio of 1:2. In addition, waveguides were also fabricated as a function of implantation energy to characterise the influence of the surface proximity

  12. Surface modification of cellulose acetate membrane using thermal annealing to enhance produced water treatment

    Science.gov (United States)

    Kusworo, T. D.; Aryanti, N.; Firdaus, M. M. H.; Sukmawati, H.

    2015-12-01

    This study is performed primarily to investigate the effect of surface modification of cellulose acetate using thermal annealing on the enhancement of membrane performance for produced water treatment. In this study, Cellulose Acetate membranes were casted using dry/wet phase inversion technique. The effect of additive and post-treatment using thermal annealing on the membrane surface were examined for produced water treatment. Therma annealing was subjected to membrane surface at 60 and 70 °C for 5, 10 and 15 second, respectively. Membrane characterizations were done using membrane flux and rejection with produced water as a feed, Scanning Electron Microscopy (SEM) and Fourier Transform Infra Red (FTIR) analysis. Experimental results showed that asymmetric cellulose acetate membrane can be made by dry/wet phase inversion technique. The results from the Scanning Electron Microscopy (FESEM) analysis was also confirmed that polyethylene glycol as additivie in dope solution and thermal annealing was affected the morphology and membrane performance for produced water treatment, respectively. Scanning electron microscopy micrographs showed that the selective layer and the substructure of membrane became denser and more compact after the thermal annealing processes. Therefore, membrane rejection was significantly increased while the flux was slighty decreased, respectively. The best membrane performance is obtained on the composition of 18 wt % cellulose acetate, poly ethylene glycol 5 wt% with thermal annealing at 70° C for 15 second.

  13. Surface modification of cellulose acetate membrane using thermal annealing to enhance produced water treatment

    Energy Technology Data Exchange (ETDEWEB)

    Kusworo, T. D., E-mail: tdkusworo@che.undip.ac.id; Aryanti, N., E-mail: nita.aryanti@gmail.com; Firdaus, M. M. H.; Sukmawati, H. [Chemical Engineering, Faculty of Engineering, Diponegoro University Prof. Soedarto Street, Tembalang, Semarang, 50239, Phone/Fax : (024)7460058 (Indonesia)

    2015-12-29

    This study is performed primarily to investigate the effect of surface modification of cellulose acetate using thermal annealing on the enhancement of membrane performance for produced water treatment. In this study, Cellulose Acetate membranes were casted using dry/wet phase inversion technique. The effect of additive and post-treatment using thermal annealing on the membrane surface were examined for produced water treatment. Therma annealing was subjected to membrane surface at 60 and 70 °C for 5, 10 and 15 second, respectively. Membrane characterizations were done using membrane flux and rejection with produced water as a feed, Scanning Electron Microscopy (SEM) and Fourier Transform Infra Red (FTIR) analysis. Experimental results showed that asymmetric cellulose acetate membrane can be made by dry/wet phase inversion technique. The results from the Scanning Electron Microscopy (FESEM) analysis was also confirmed that polyethylene glycol as additivie in dope solution and thermal annealing was affected the morphology and membrane performance for produced water treatment, respectively. Scanning electron microscopy micrographs showed that the selective layer and the substructure of membrane became denser and more compact after the thermal annealing processes. Therefore, membrane rejection was significantly increased while the flux was slighty decreased, respectively. The best membrane performance is obtained on the composition of 18 wt % cellulose acetate, poly ethylene glycol 5 wt% with thermal annealing at 70° C for 15 second.

  14. Thermal annealing effects on AlGaAsSb/GaSb laser structure: Bandgap energy blueshift and thermal conductivity enhancement

    Science.gov (United States)

    Ilahi, S.; Yacoubi, N.; Genty, F.

    2017-07-01

    In this paper, we have investigated the effects of thermal annealing on optical properties and thermal conductivity of AlGaAsSb/GaSb laser structure using photo-thermal deflection spectroscopy PDS. In fact, optical absorption spectrum and thermal conductivity have been determined by comparison between experimental and theoretical phase of PDS signal. We have found that band gap energy is blue shifted of 70 meV for the as grown to the sample annealed for 1 h. Indeed, the highest thermal conductivity is found around of 11 W/m.K for AlGaAsSb/GaSb annealed for 1 h, which presents a promising result for vertical-cavity surface-emitting lasers (VCSELs).

  15. Thermal annealing of protocrystalline a-Si:H

    NARCIS (Netherlands)

    Muller, T.F.G.; Arendse, C.J.; Halindintwali, S.; Knoesen, D.; Schropp, R.E.I.

    2011-01-01

    It proves difficult to obtain a set of protocrystalline silicon materials with different characteristics from the same deposition chamber to study the exact nature of these transition region materials. Hot-wire deposited protocrystalline silicon was thus isochronically annealed at different

  16. Electric field assisted thermal annealing reorganization of graphene oxide/polystyrene latex films

    Directory of Open Access Journals (Sweden)

    2011-09-01

    Full Text Available Graphene/polymer films were prepared by casting water dispersion of graphene oxide (GO in the presence of polystyrene (PS latex particles. The samples were heated up to 180°C and exposed to an external electric voltage during their annealing. We observed that for the GO/PS films deposited before the electric field assisted thermal annealing the polymer latex was embedded in the graphene sheets, while the electric field assisted thermal annealing induces a phase separation with the enrichment of the PS phase above an underlying GO layer. For the films annealed under an external electric field we have also found that as the electric current passes through the GO film, GO could be recovered to reduced GO with decreased resistance.

  17. Relationship between beta radiation induced thermoluminescence and thermal annealing procedures in ZrO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Rivera, T. [ESIME-IPN, Culhuacan, 04430 Mexico D.F. (Mexico); Azorin, J.; Campero, A.; Velasquez, C. [UAM-I, 09340 Mexico D.F. (Mexico); Furetta, C. [Physics Department, Rome University ' ' La Sapienza' ' , Rome (Italy)

    2004-07-01

    The influence of thermal treatment on the glow curve characteristics of undoped ZrO2 polycrystalline powder were studied in the range 700 to 1100 . The TL intensity of annealed ZrO2 powder, previously exposed to a given beta dose, submitted to different thermal treatments in the range from 700 to 1100 increases as the annealing temperature is increased. The TL glow curve of ZrO2 powder beta irradiated at absorbed doses up to 20 Gy exhibited a single peak centered at 200 . Furthermore, if the absorbed dose is increased up to 25 Gy the glow curve changes, appearing a second peak with its maximum centered at 250 . Then, it could be concluded that the TL response of ZrO2 powder is closely related to the annealing procedures and the creation of charge trapping centers corresponding to the 200 and 250 TL peaks depends on the annealing temperature. (Author)

  18. Silicon nanoparticle synthesis by short-period thermal anneals at atmospheric pressure in argon

    International Nuclear Information System (INIS)

    Spencer, Gregory; Anyamesem-Mensah, Benedict; Galloway, Heather C.; Bandyopadhyay, Anup; Frasier, Daniel

    2011-01-01

    Silicon nanoparticles have been studied for a wide variety of applications including nanoelectronic, photovoltaic, and optoelectronic devices. In this work, silicon nanoparticles were synthesized by short-period annealing of silicon-on-insulator substrates to temperatures ranging between 600 and 900 deg. C in argon gas at atmospheric pressure. Two different top silicon layers were deposited by ion-beam sputtering onto oxidized substrates. The thinner 6 nm top layer samples were annealed to temperatures for 30 s periods while thicker 15 nm top layer samples were annealed for 60 s periods. For both sets of samples, nanoparticles were observed to form at all the anneal temperatures through imaging by AFM. One long-period UHV anneal study, with 30-min anneal times, observed nanoparticle formation at temperatures similar to the current work while another similar long-period UHV anneal reported nanoparticle formation only above well-defined formation temperatures that depended upon the starting top layer thickness. In the current work, the average nanoparticle radius was found to increase both with the final anneal temperature and anneal period. For the highest anneal temperatures of the 6 nm top layer samples, a changing surface topography indicated that the thinner Si source layer was becoming depleted and the nanoparticle formation process was nearing completion. No such changes were observed for the thicker 15 nm samples at the same temperatures.

  19. Structural, Optical, and Dielectric Properties of Azure B Thin Films and Impact of Thermal Annealing

    Science.gov (United States)

    Zeyada, H. M.; Zidan, H. M.; Abdelghany, A. M.; Abbas, I.

    2017-07-01

    Thin films of azure B (AB) have been prepared by thermal evaporation. Structural, optical, and dielectric characteristics of as-prepared and annealed samples were studied. AB is polycrystalline in as-synthesized powder form. Detailed x-ray diffraction studies showed amorphous structure for pristine and annealed films. Fourier-transform infrared vibrational spectroscopy indicated minor changes in molecular bonds of AB thin films either after deposition or after thermal annealing. Optical transmittance and reflection spectra of prepared thin films were studied at nearly normal light incidence in the spectral range from 200 nm to 2500 nm, showing marked changes without new peaks. Annealing increased the absorption coefficient and decreased the optical bandgap. Onset and optical energy gaps of pristine films were found to obey indirect allowed transition with values of 1.10 eV and 2.64 eV, respectively. Annealing decreased the onset and optical energy gaps to 1.0 eV and 2.57 eV, respectively. The dispersion parameters before and after annealing are discussed in terms of a single-oscillator model. The spectra of the dielectric constants ( ɛ 1, ɛ 2) were found to depend on the annealing temperature in addition to the incident photon energy.

  20. Enhanced bolometric properties of TiO2-x thin films by thermal annealing

    Science.gov (United States)

    Ashok Kumar Reddy, Y.; Shin, Young Bong; Kang, In-Ku; Lee, Hee Chul; Sreedhara Reddy, P.

    2015-07-01

    The effect of thermal annealing on the bolometric properties of TiO2-x films was investigated. The test-patterned TiO2-x samples were annealed at 300 °C temperature in order to enhance their structural and electrical properties for effective infrared image sensor device applications. The crystallinity was changed from amorphous to rutile/anatase in annealed TiO2-x films. Compared to the as-deposited samples, a decrement of the band gap and a decrease of the electrical resistivity were perceived in annealed samples. We found that the annealed samples show linear current-voltage (I-V) characteristic performance, which implies that ohmic contact was well formed at the interface between the TiO2-x and the Ti electrode. Moreover, the annealed TiO2-x sample had a significantly low 1/f noise parameter (1.21 × 10-13) with a high bolometric parameter (β) value compared to those of the as-deposited samples. As a result, the thermal annealing process can be used to prepare TiO2-x film for a high-performance bolometric device.

  1. Pd-based alloy nanoclusters in ion-implanted silica: Formation and stability under thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Battaglin, G.; Cattaruzza, E.; De Marchi, G.; Gonella, F.; Mattei, G. E-mail: mattei@padova.infm.it; Maurizio, C.; Mazzoldi, P.; Parolin, M.; Sada, C.; Calliari, I

    2002-05-01

    In this work we report on the formation and stability under thermal annealing of Pd-Cu and Pd-Ag alloy nanoclusters obtained by sequential ion implantation in silica. The role of the annealing atmosphere on the alloy cluster formation and stability is investigated. A comparison is made with similar alloy-based systems obtained by sequential ion implantation in silica of Au-Ag or Au-Cu followed by annealing under similar conditions, in order to evidence the peculiar effect of the various metals in controlling the alloy evolution and/or decomposition.

  2. Thermal annealing recovery of fracture toughness in HT9 steel after irradiation to high doses

    Energy Technology Data Exchange (ETDEWEB)

    Byun, Thak Sang, E-mail: byunts@ornl.gov [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Baek, Jong-Hyuk [Korea Atomic Energy Research Institute, Daejeon 305-353 (Korea, Republic of); Anderoglu, Osman; Maloy, Stuart A. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Toloczko, Mychailo B. [Pacific Northwest National Laboratory, Richland, WA 99352 (United States)

    2014-06-01

    The HT9 ferritic/martensitic steel with a nominal chemistry of Fe(bal.)12%Cr1%MoVW has been used as a primary core material for fast fission reactors such as FFTF because of its high resistance to radiation-induced swelling and embrittlement. Both static and dynamic fracture test results have shown that the HT9 steel can become brittle when it is exposed to high dose irradiation at a relatively low temperature (<430 °C). This article aims at a comprehensive discussion on the thermal annealing recovery of fracture toughness in the HT9 steel after irradiation up to 3148 dpa at 378504 °C. A specimen reuse technique has been established and applied to this study: the fracture specimens were tested Charpy specimens or broken halves of Charpy bars (13 × 3 × 4 mm). The post-anneal fracture test results indicated that much of the radiation-induced damage can be recovered by a simple thermal annealing schedule: the fracture toughness was incompletely recovered by 550 °C annealing, while nearly complete or complete recovery occurred after 650 °C annealing. This indicates that thermal annealing is a feasible damage mitigation technique for the reactor components made of HT9 steel. The partial recovery is probably due to the non-removable microstructural damages such as void or gas bubble formation, elemental segregation and precipitation.

  3. Investigation of thermal annealing effects on microstructural and optical properties of HfO{sub 2} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Modreanu, M. [Tyndall National Institute, Cork (Ireland)]. E-mail: mircea.modreanu@tyndall.ie; Sancho-Parramon, J. [Tyndall National Institute, Cork (Ireland); Durand, O. [Thales Research and Technology France, Route Departementale 128, F-91767 Palaiseau Cedex (France); Servet, B. [Thales Research and Technology France, Route Departementale 128, F-91767 Palaiseau Cedex (France); Stchakovsky, M. [Horiba Jobin-Yvon, Thin Film Division, Chilly-Mazarin (France); Eypert, C. [Horiba Jobin-Yvon, Thin Film Division, Chilly-Mazarin (France); Naudin, C. [HORIBA Jobin-Yvon Raman Division, Villeneuve d' Ascq (France); Knowles, A. [HORIBA Jobin-Yvon Ltd., Raman Division, Middlesex (United Kingdom); Bridou, F. [Laboratoire Charles Fabry de l' Institut d' Optique, CNRS, Unite mixte de Recherche 85801, 91403 Orsay Cedex (France); Ravet, M.-F. [Laboratoire Charles Fabry de l' Institut d' Optique, CNRS, Unite mixte de Recherche 85801, 91403 Orsay Cedex (France)

    2006-10-31

    In the present paper, we investigate the effect of thermal annealing on optical and microstructural properties of HfO{sub 2} thin films (from 20 to 190 nm) obtained by plasma ion assisted deposition (PIAD). After deposition, the HfO{sub 2} films were annealed in N{sub 2} ambient for 3 h at 300, 350, 450, 500 and 750 deg. C. Several characterisation techniques including X-ray reflectometry (XRR), X-ray diffraction (XRD), spectroscopic ellipsometry (SE), UV Raman and FTIR were used for the physical characterisation of the as-deposited and annealed HfO{sub 2} thin films. The results indicate that as-deposited PIAD HfO{sub 2} films are mainly amorphous and a transition to a crystalline phase occurs at a temperature higher than 450 deg. C depending on the layer thickness. The crystalline grains consist of cubic and monoclinic phases already classified in literature but this work provides the first evidence of amorphous-cubic phase transition at a temperature as low as 500 deg. C. According to SE, XRR and FTIR results, an increase in the interfacial layer thickness can be observed only for high temperature annealing. The SE results show that the amorphous phase of HfO{sub 2} (in 20 nm thick samples) has an optical bandgap of 5.51 eV. Following its transition to a crystalline phase upon annealing at 750 deg. C, the optical bandgap increases to 5.85 eV.

  4. Including gauge corrections to thermal leptogenesis

    International Nuclear Information System (INIS)

    Huetig, Janine

    2013-01-01

    This thesis provides the first approach of a systematic inclusion of gauge corrections to leading order to the ansatz of thermal leptogenesis. We have derived a complete expression for the integrated lepton number matrix including all resummations needed. For this purpose, a new class of diagram has been invented, namely the cylindrical diagram, which allows diverse investigations into the topic of leptogenesis such as the case of resonant leptogenesis. After a brief introduction of the topic of the baryon asymmetry in the universe and a discussion of its most promising solutions as well as their advantages and disadvantages, we have presented our framework of thermal leptogenesis. An effective model was described as well as the associated Feynman rules. The basis for using nonequilibrium quantum field theory has been built in chapter 3. At first, the main definitions have been presented for equilibrium thermal field theory, afterwards we have discussed the Kadanoff-Baym equations for systems out of equilibrium using the example of the Majorana neutrino. The equations have also been solved in the context of leptogenesis in chapter 4. Since gauge corrections play a crucial role throughout this thesis, we have also repeated the naive ansatz by replacing the free equilibrium propagator by propagators including thermal damping rates due to the Standard Model damping widths for lepton and Higgs fields. It is shown that this leads to a comparable result to the solutions of the Boltzmann equations for thermal leptogenesis. Thus it becomes obvious that Standard Model corrections are not negligible for thermal leptogenesis and therefore need to be included systematically from first principles. In order to achieve this we have started discussing the calculation of ladder rung diagrams for Majorana neutrinos using the HTL and the CTL approach in chapter 5. All gauge corrections are included in this framework and thus it has become the basis for the following considerations

  5. Transmission electron microscope studies of laser and thermally annealed ion implanted silicon

    International Nuclear Information System (INIS)

    Narayan, J.; Young, R.T.; White, C.W.

    1978-01-01

    Transmission electron microscopy has been used to study the effects of high power laser pulses on boron, phosphorous and arsenic implanted [100] silicon crystals. No defects (dislocations, dislocation loops and/or stacking faults) were observed in either as-grown or implanted silicon after one pulse of ruby laser irradiation (lambda = 0.694 μm, pulse energy density 1.5 to 1.8 J cm -2 , 50 x 10 -9 pulse duration time). The concentration of boron in solution, as inferred from electrical measurements, could exceed the equilibrium solubility. In thermally annealed specimens, on the other hand, significant damage remained even after annealing at 1100 0 C for 30 minutes. On thermally annealing the implanted, laser-treated specimens, precipitation of the implanted boron ions occurred whenever the implanted doses were in excess of the equilibrium solubility limits. The relationship of these observations to the results of electrical measurements made on these samples will be discussed

  6. Phase formation polycrystalline vanadium oxide via thermal annealing process under controlled nitrogen pressure

    Science.gov (United States)

    Jessadaluk, S.; Khemasiri, N.; Rahong, S.; Rangkasikorn, A.; Kayunkid, N.; Wirunchit, S.; Horprathum, M.; Chananonnawathron, C.; Klamchuen, A.; Nukeaw, J.

    2017-09-01

    This article provides an approach to improve and control crystal phases of the sputtering vanadium oxide (VxOy) thin films by post-thermal annealing process. Usually, as-deposited VxOy thin films at room temperature are amorphous phase: post-thermal annealing processes (400 °C, 2 hrs) under the various nitrogen (N2) pressures are applied to improve and control the crystal phase of VxOy thin films. The crystallinity of VxOy thin films changes from amorphous to α-V2O5 phase or V9O17 polycrystalline, which depend on the pressure of N2 carrier during annealing process. Moreover, the electrical resistivity of the VxOy thin films decrease from 105 Ω cm (amorphous) to 6×10-1 Ω cm (V9O17). Base on the results, our study show a simply method to improve and control phase formation of VxOy thin films.

  7. Development of a supplemental surveillance program for reactor pressure vessel thermal annealing

    International Nuclear Information System (INIS)

    Server, W.L.; Rosinski, S.T.

    1997-01-01

    The technical decision to thermally anneal a nuclear reactor pressure vessel (RPV) depends upon the level of embrittlement in the RPV steels, the amount of recovery of fracture toughness properties expected from the anneal, and the rate of re-embrittlement after the vessel is placed back into service. The recovery of Charpy impact toughness properties after annealing can be estimated initially by using a recovery model developed using experimental measurements of recovery (such as that developed by Eason et al. for U.S. vessel materials). However, actual validation measurements on plant-specific archived vessel materials (hopefully in the existing surveillance program) are needed; otherwise, irradiated surrogate materials, essentially the same as the RPV steels or bounding in expected behavior, must be utilized. The efficient use of any of these materials requires a supplemental surveillance program focused at both recovery and reirradiation embrittlement. Reconstituted Charpy specimens and new surveillance capsules will most likely be needed as part of this supplemental surveillance program. A new version of ASTM E 509 has recently been approved which provides guidance on thermal annealing in general and specifically for the development of an annealing supplemental surveillance program. The post-anneal re-embrittlement properties are crucial for continued plant operation, and the use of a re-embrittlement model, such as the lateral shift approach, may be overly conservative. This paper illustrates the new ASTM E 509 Standard Guide methodology for an annealing supplemental surveillance program. As an example, the proposed program for the Palisades RPV beltline steels is presented which covers the time from annealing to the end of operating license and beyond, if license renewal is pursued. The Palisades nuclear power plant RPV was planned to be annealed in 1998, but that plant is currently being re-evaluated. The proposed anneal was planned to be conducted at a

  8. Thermal annealing response following irradiation of a CMOS imager for the JUICE JANUS instrument

    Science.gov (United States)

    Lofthouse-Smith, D.-D.; Soman, M. R.; Allanwood, E. A. H.; Stefanov, K. D.; Holland, A. D.; Leese, M.; Turne, P.

    2018-03-01

    ESA's JUICE (JUpiter ICy moon Explorer) spacecraft is an L-class mission destined for the Jovian system in 2030. Its primary goals are to investigate the conditions for planetary formation and the emergence of life, and how does the solar system work. The JANUS camera, an instrument on JUICE, uses a 4T back illuminated CMOS image sensor, the CIS115 designed by Teledyne e2v. JANUS imager test campaigns are studying the CIS115 following exposure to gammas, protons, electrons and heavy ions, simulating the harsh radiation environment present in the Jovian system. The degradation of 4T CMOS device performance following proton fluences is being studied, as well as the effectiveness of thermal annealing to reverse radiation damage. One key parameter for the JANUS mission is the Dark current of the CIS115, which has been shown to degrade in previous radiation campaigns. A thermal anneal of the CIS115 has been used to accelerate any annealing following the irradiation as well as to study the evolution of any performance characteristics. CIS115s have been irradiated to double the expected End of Life (EOL) levels for displacement damage radiation (2×1010 protons, 10 MeV equivalent). Following this, devices have undergone a thermal anneal cycle at 100oC for 168 hours to reveal the extent to which CIS115 recovers pre-irradiation performance. Dark current activation energy analysis following proton fluence gives information on trap species present in the device and how effective anneal is at removing these trap species. Thermal anneal shows no quantifiable change in the activation energy of the dark current following irradiation.

  9. Synthesis of B–Sb by rapid thermal annealing of B/Sb multilayer films

    Indian Academy of Sciences (India)

    layer with predetermined thickness of boron and antimony and subsequently subjecting the multilayer to rapid thermal annealing. The films were characterized by measuring microstructural, optical and compositional properties. 2. Experimental. Multilayer films of B and Sb were deposited onto Si and fused silica substrates ...

  10. Effect of thermal annealing on optical properties of implanted GaAs

    NARCIS (Netherlands)

    Kulik, M; Komarov, FF; Maczka, D

    GaAs samples doped with indium atoms by ion implantation and thermal annealed were studied using a channelling method, Rutherford backscattering, and an ellipsometry. From these measurements it was observed that the layer implanted with 3 x 10(16) cm(-2) indium dose was totally damaged and its

  11. A novel method for biopolymer surface nanostructuring by platinum deposition and subsequent thermal annealing

    Czech Academy of Sciences Publication Activity Database

    Slepička, P.; Juřík, P.; Kolská, Z.; Malinský, Petr; Macková, Anna; Michaljaničová, I.; Švorčík, V.

    2012-01-01

    Roč. 7, č. 671 (2012), s. 1-6 ISSN 1931-7573 R&D Projects: GA ČR(CZ) GBP108/12/G108 Institutional support: RVO:61389005 Keywords : nanopattering * surface morphology * biopolymer * platinum sputtering * thermal annealing Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 2.524, year: 2012

  12. Magnetic structure of Fe-based amorphous and thermal annealed microwires

    Energy Technology Data Exchange (ETDEWEB)

    Olivera, J. [Depto. Fisica, Universidad de Oviedo, Calvo Sotelo s/n, 33007 Oviedo (Spain); Provencio, M. [Instituto de Ciencia de Materiales, CSIC, Cantoblanco, 28049 Madrid (Spain); Prida, V.M. [Depto. Fisica, Universidad de Oviedo, Calvo Sotelo s/n, 33007 Oviedo (Spain); Hernando, B. [Depto. Fisica, Universidad de Oviedo, Calvo Sotelo s/n, 33007 Oviedo (Spain)]. E-mail: grande@pinon.ccu.uniovi.es; Santos, J.D. [Depto. Fisica, Universidad de Oviedo, Calvo Sotelo s/n, 33007 Oviedo (Spain); Perez, M.J. [Depto. Fisica, Universidad de Oviedo, Calvo Sotelo s/n, 33007 Oviedo (Spain); Gorria, P. [Depto. Fisica, Universidad de Oviedo, Calvo Sotelo s/n, 33007 Oviedo (Spain); Sanchez, M.L. [Depto. Fisica, Universidad de Oviedo, Calvo Sotelo s/n, 33007 Oviedo (Spain); Belzunce, F.J. [Depto. Ciencia de los Materiales e Ingenieria Metalurgica, Universidad de Oviedo, Independencia 13, 33004 Oviedo (Spain)

    2005-07-15

    The magnetic structure of amorphous and thermal annealed glass coated microwires is studied by thermomagnetic, DSC, and Bitter domain pattern techniques. The long-range dipolar interaction between parallel aligned microwires and the appearance of large Barkhausen jumps steps in the axially magnetized loops are discussed in terms of reversal magnetization process.

  13. Thermal design and analysis of the HTGR fuel element vertical carbonizing and annealing furnace

    International Nuclear Information System (INIS)

    Llewellyn, G.H.

    1977-06-01

    Computer analyses of the thermal design for the proposed HTGR fuel element vertical carbonizing and annealing furnace were performed to verify its capability and to determine the required power input and distribution. Although the furnace is designed for continuous operation, steady-state temperature distributions were obtained by assuming internal heat generation in the fuel elements to simulate their mass movement. The furnace thermal design, the analysis methods, and the results are discussed herein

  14. Simulation of the diffusion of implanted impurities in silicon structures at the rapid thermal annealing

    International Nuclear Information System (INIS)

    Komarov, F.F.; Komarov, A.F.; Mironov, A.M.; Makarevich, Yu.V.; Miskevich, S.A.; Zayats, G.M.

    2011-01-01

    Physical and mathematical models and numerical simulation of the diffusion of implanted impurities during rapid thermal treatment of silicon structures are discussed. The calculation results correspond to the experimental results with a sufficient accuracy. A simulation software system has been developed that is integrated into ATHENA simulation system developed by Silvaco Inc. This program can simulate processes of the low-energy implantation of B, BF 2 , P, As, Sb, C ions into the silicon structures and subsequent rapid thermal annealing. (authors)

  15. Thermal annealing recovery of fracture toughness in HT9 steel after irradiation to high doses

    Science.gov (United States)

    Byun, Thak Sang; Baek, Jong-Hyuk; Anderoglu, Osman; Maloy, Stuart A.; Toloczko, Mychailo B.

    2014-06-01

    The HT9 ferritic/martensitic steel with a nominal chemistry of Fe(bal.)12%Cr1%MoVW has been used as a primary core material for fast fission reactors such as FFTF because of its high resistance to radiation-induced swelling and embrittlement. Both static and dynamic fracture test results have shown that the HT9 steel can become brittle when it is exposed to high dose irradiation at a relatively low temperature (steel after irradiation up to 3148 dpa at 378504 °C. A specimen reuse technique has been established and applied to this study: the fracture specimens were tested Charpy specimens or broken halves of Charpy bars (13 × 3 × 4 mm). The post-anneal fracture test results indicated that much of the radiation-induced damage can be recovered by a simple thermal annealing schedule: the fracture toughness was incompletely recovered by 550 °C annealing, while nearly complete or complete recovery occurred after 650 °C annealing. This indicates that thermal annealing is a feasible damage mitigation technique for the reactor components made of HT9 steel. The partial recovery is probably due to the non-removable microstructural damages such as void or gas bubble formation, elemental segregation and precipitation.

  16. Characterization for Ceramic-coated magnets using E-beam and thermal annealing methods

    International Nuclear Information System (INIS)

    Kim, Hyug Jong; Kim, Hee Gyu; Kang, In Gu; Kim, Min Wan; Yang, Ki Ho; Lee, Byung Cheol; Choi, Byung Ho

    2009-01-01

    Hard magnet was usually used by coating SiO 2 ceramic thick films followed by the thermal annealing process. In this work, the alternative annealing process for NdFeB magnets using e-beam sources(1∼2 MeV, 50∼400 kGy) was investigated. NdFeB magnets was coated with ceramic thick films using the spray method. The optimal annealing parameter for e-beam source reveals to be 1 MeV and 300 kGy. The sample prepared at 1 MeV and 300 kGy was characterized by the analysis of the surface morphology, film hardness, adhesion and chemical stability. The mechanical property of thick film, especially film hardness, is better than that of thermal annealed samples at 180 .deg. C. As a result, e-beam annealing process will be one of candidate and attractive heat treatment process. In future, manufacturing process will be carried out in cooperation with the magnet company

  17. Structural changes induced by thermal annealing in Cr/C multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Tu, Yuchun [MOE Key Laboratory of Advanced Micro-structured Materials, School of Physics Science and Engineering, Tongji University, Shanghai 200092 (China); Sorbonne Universités, UPMC Univ Paris 06, Laboratoire de Chimie Physique-Matière et Rayonnement, 11 rue Pierre et Marie Curie, F-75231 Paris cedex 05 (France); CNRS UMR 7614, Laboratoire de Chimie Physique-Matière et Rayonnement, 11 rue Pierre et Marie Curie, F-75231 Paris cedex 05 (France); Zhu, Jingtao, E-mail: jtzhu@tongji.edu.cn [MOE Key Laboratory of Advanced Micro-structured Materials, School of Physics Science and Engineering, Tongji University, Shanghai 200092 (China); Li, Haochuan [MOE Key Laboratory of Advanced Micro-structured Materials, School of Physics Science and Engineering, Tongji University, Shanghai 200092 (China); Jonnard, Philippe; Le Guen, Karine; André, Jean-Michel [Sorbonne Universités, UPMC Univ Paris 06, Laboratoire de Chimie Physique-Matière et Rayonnement, 11 rue Pierre et Marie Curie, F-75231 Paris cedex 05 (France); CNRS UMR 7614, Laboratoire de Chimie Physique-Matière et Rayonnement, 11 rue Pierre et Marie Curie, F-75231 Paris cedex 05 (France); Chen, Hong [MOE Key Laboratory of Advanced Micro-structured Materials, School of Physics Science and Engineering, Tongji University, Shanghai 200092 (China); Wang, Zhanshan, E-mail: wangzs@tongji.edu.cn [MOE Key Laboratory of Advanced Micro-structured Materials, School of Physics Science and Engineering, Tongji University, Shanghai 200092 (China)

    2014-09-15

    Highlights: • We reported experimental results on thermal effects of Cr/C multilayer. • The period thicknesses of Cr/C multilayers expand or contract with different carbon layer thickness ratios upon 600 °C annealing. • More chromium carbide formed at the interfaces after annealing. - Abstract: The structural changes induced by thermal annealing in Cr/C multilayers were investigated. Cr/C multilayers with period thickness of 5 nm and bi-layer number of 30 were deposited by direct current magnetron sputtering, and characterized by using grazing incidence X-ray reflectivity, X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. The results suggest that the period thicknesses of Cr/C multilayers expand or contract with different carbon layer thickness ratios (the ratio of the carbon layer thickness to the multilayer period) upon annealing and the physical mechanism was explored in detail. Carbon layer in Cr/C multilayers become graphitized from amorphous state. Such graphitization of the carbon layer causes a decrease in its density, thus an increase in its thickness. The annealing process also causes a reduction in period due to the formation of denser carbide, which can be confirmed by the XPS results.

  18. Conventional and rapid thermal annealing of spray pyrolyzed copper indium gallium sulfide thin films

    International Nuclear Information System (INIS)

    Aydin, Erkan; Sankir, Mehmet; Sankir, Nurdan Demirci

    2014-01-01

    Highlights: • Spray pyrolysis of copper indium gallium sulfide (CuInGaS 2 ) thin films. • Environmentally friendly method to produce solar cell quality absorber layers. • Effects of post-annealing process on the film properties of CuInGaS 2 . • Pros-and-cons of conventional and rapid thermal annealing. • Enhanced electrical and optical properties via annealing. - Abstract: With this study for the first time effects of post annealing on morphological, structural, optical and electrical properties of spray pyrolyzed copper–indium–gallium–sulfide (CuInGaS 2 ) thin films have been investigated. Pros-and-cons of conventional (CA) and rapid thermal annealing (RTA) have been discussed to obtain the high quality thin film absorbers for solar cell applications. X-ray diffraction analysis revealed that all of the spray pyrolyzed CuInGaS 2 thin films have chalcopyrite structures with a highly (1 1 2) preferential orientation. Raman spectra also confirmed this structure. However, metal oxide secondary phases such as copper oxide and gallium oxide were detected when the temperature ramp rate was increased during RTA process. Energy dispersive X-ray measurements revealed that both copper and gallium diffused through the surface after annealing processes. Moreover, copper diffusion became pronounced especially at high annealing temperatures. Optical transmission measurements in the wavelength range between 600 and 1100 nm showed that band gap energy of CuInGaS 2 thin films was ranging between 1.36 and 1.51 eV depending on the annealing conditions. Very high mobility values have been observed for both processes. The maximum electrical mobility, 30.9 cm 2 /V s, was observed for the films annealed at 600 °C via CA. This is the highest reported value among the CuInGaS 2 thin film absorbers deposited by both solution and vacuum based techniques. As a result, post-annealing of spray pyrolyzed CuInGaS 2 thin films without usage of highly toxic gases, reported in this

  19. Dewetting of Epitaxial Silver Film on Silicon by Thermal Annealing

    Science.gov (United States)

    Sanders, Charlotte E.; Kellogg, Gary L.; Shih, C.-K.

    2013-03-01

    It has been shown that noble metals can grow epitaxially on semiconducting and insulating substrates, despite being a non-wetting system: low temperature deposition followed by room temperature annealing leads to atomically flat film morphology. However, the resulting metastable films are vulnerable to dewetting, which has limited their utility for applications under ambient conditions. The physics of this dewetting is of great interest but little explored. We report on an investigation of the dewetting of epitaxial Ag(111) films on Si(111) and (100). Low energy electron microscopy (LEEM) shows intriguing evolution in film morphology and crystallinity, even at temperatures below 100oC. On the basis of these findings, we can begin to draw compelling inferences about film-substrate interaction and the kinetics of dewetting. Financial support is from NSF, DGE-0549417 and DMR-0906025. This work was performed, in part, at the Center for Integrated Nanotechnologies, User Facility operated for the U.S. DOE Office of Science. Sandia National Lab is managed and operated by Sandia Corp., a subsidiary of Lockheed Martin Corp., for the U.S. DOE's National Nuclear Security Administration under DE-AC04-94AL85000.

  20. Rapid thermal annealing of FePt and FePt/Cu thin films

    Energy Technology Data Exchange (ETDEWEB)

    Brombacher, Christoph

    2011-01-10

    Chemically ordered FePt is one of the most promising materials to reach the ultimate limitations in storage density of future magnetic recording devices due to its high uniaxial magnetocrystalline anisotropy and a corrosion resistance superior to rare-earth based magnets. In this study, FePt and FePt/Cu bilayers have been sputter deposited at room temperature onto thermally oxidized silicon wafers, glass substrates and self-assembled arrays of spherical SiO{sub 2} particles with diameters down to 10 nm. Millisecond flash lamp annealing, as well as conventional rapid thermal annealing was employed to induce the phase transformation from the chemically disordered A1 phase into the chemically ordered L1{sub 0} phase. The influence of the annealing temperature, annealing time and the film thickness on the ordering transformation and (001) texture evolution of FePt films with near equiatomic composition was studied. Whereas flash lamp annealed FePt films exhibit a polycrystalline morphology with high chemical L1{sub 0} order, rapid thermal annealing can lead to the formation of chemically ordered FePt films with (001) texture on amorphous SiO{sub 2}/Si substrates. The resultant high perpendicular magnetic anisotropy and large coercivities up to 40 kOe are demonstrated. Simultaneously to the ordering transformation, rapid thermal annealing to temperatures exceeding 600 C leads to a break up of the continuous FePt film into separated islands. This dewetting behavior was utilized to create regular arrays of FePt nanostructures on SiO{sub 2} particle templates with periods down to 50 nm. The addition of Cu improves the (001) texture formation and chemical ordering for annealing temperatures T{sub a} {<=}600 C. In addition, the magnetic anisotropy and the coercivity of the ternary FePtCu alloy can be effectively tailored by adjusting the Cu content. The prospects of FePtCu based exchange spring media, as well as the magnetic properties of FePtCu nanostructures fabricated

  1. Self-Healing Thermal Annealing: Surface Morphological Restructuring Control of GaN Nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Conroy, Michele; Li, Haoning; Zubialevich, Vitaly Z.; Kusch, Gunnar; Schmidt, Michael; Collins, Timothy; Glynn, Colm; Martin, Robert W.; O’Dwyer, Colm; Morris, Michael D.; Holmes, Justin D.; Parbrook, Peter J.

    2016-12-07

    With advances in nanolithography and dry etching, top-down methods of nanostructuring have become a widely used tool for improving the efficiency of optoelectronics. These nano dimensions can offer various benefits to the device performance in terms of light extraction and efficiency, but often at the expense of emission color quality. Broadening of the target emission peak and unwanted yellow luminescence are characteristic defect-related effects due to the ion beam etching damage, particularly for III–N based materials. In this article we focus on GaN based nanorods, showing that through thermal annealing the surface roughness and deformities of the crystal structure can be “self-healed”. Correlative electron microscopy and atomic force microscopy show the change from spherical nanorods to faceted hexagonal structures, revealing the temperature-dependent surface morphology faceting evolution. The faceted nanorods were shown to be strain- and defect-free by cathodoluminescence hyperspectral imaging, micro-Raman, and transmission electron microscopy (TEM). In-situ TEM thermal annealing experiments allowed for real time observation of dislocation movements and surface restructuring observed in ex-situ annealing TEM sampling. This thermal annealing investigation gives new insight into the redistribution path of GaN material and dislocation movement post growth, allowing for improved understanding and in turn advances in optoelectronic device processing of compound semiconductors.

  2. Synthesis of borides in molybdenum implanted by B+ ions under thermal and electron annealing

    International Nuclear Information System (INIS)

    Kazdaev, Kh.R.; Akchulakov, M.T.; Bayadilov, E.M.; Ehngel'ko, V.I.; Lazarenko, A.V.; Chebukov, E.S.

    1989-01-01

    The possibility of formation of borides in the near surface layers of monocrystalline molybdenum implanted by boron ions at 35 keV energy under thermal and pulsed electron annealing by an electon beam at 140 keV energy is investigated. It is found that implantation of boron ions into molybdenum with subsequent thermal annealing permits to produce both molybdenum monoboride (α-MoB) and boride (γ-Mo 2 B) with rather different formation mechanisms. Formation of the α-MoB phase occurs with the temperature elevation from the centers appeared during implantation, while the γ-Mo 2 B phase appears only on heating the implanted layers up to definite temperature as a result of the phase transformation of the solid solution into a chemical compound. Pulsed electron annealing instead of thermal annealing results mainly in formation of molybdenum boride (γ-Mo 2 B), the state of structure is determined by the degree of heating of implanted layers and their durable stay at temperatures exceeding the threshold values

  3. Effects of Thermal Annealing Upon the Morphology of Polymer-Fullerene Blends

    KAUST Repository

    Verploegen, Eric

    2010-08-18

    Grazing incidence X-ray scattering (GIXS) is used to characterize the morphology of poly(3-hexylthiophene) (P3HT)-phenyl-C61-butyric acid methyl ester (PCBM) thin film bulk heterojunction (BHJ) blends as a function of thermal annealing temperature, from room temperature to 220 °C. A custom-built heating chamber for in situ GIXS studies allows for the morphological characterization of thin films at elevated temperatures. Films annealed with a thermal gradient allow for the rapid investigation of the morphology over a range of temperatures that corroborate the results of the in situ experiments. Using these techniques the following are observed: the melting points of each component; an increase in the P3HT coherence length with annealing below the P3HT melting temperature; the formation of well-oriented P3HT crystallites with the (100) plane parallel to the substrate, when cooled from the melt; and the cold crystallization of PCBM associated with the PCBM glass transition temperature. The incorporation of these materials into BHJ blends affects the nature of these transitions as a function of blend ratio. These results provide a deeper understanding of the physics of how thermal annealing affects the morphology of polymer-fullerene BHJ blends and provides tools to manipulate the blend morphology in order to develop high-performance organic solar cell devices. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Recombination luminescence in irradiated silicon - Effects of thermal annealing and lithium impurity.

    Science.gov (United States)

    Johnson, E. S.; Compton, W. D.

    1971-01-01

    Use of luminescence in irradiated silicon to determine the thermal stability of the defects responsible for the recombination. It is found that the defect responsible for the zero-phonon line at 0.97 eV has an annealing behavior similar to that of the divacancy and that the zero-phonon line at 0.79 eV anneals in a manner similar to the G-15 or K-center. Annealing at temperatures up to 500 C generates other defects whose luminescence is distinct from that seen previously. Addition of lithium to the material produces defects with new characteristic luminescence. Of particular importance is a defect with a level at E sub g -1.045 eV.

  5. Thermal annealing effects on non-peripheral octahexylphthalocyanine doped polymer bulk heterojunction solar cells

    Science.gov (United States)

    De Romeo Banoukepa, Gilles; Masuda, Tetsuya; Fujii, Akihiko; Shimizu, Yo; Ozaki, Masanori

    2014-01-01

    We investigated the thermal annealing temperature dependence of the photovoltaic properties of organic thin film solar cells based on a bulk heterojunction of poly(3-hexylthiophene) (P3HT) and 1-(3-methoxy-carbonyl)-propyl-1-1-phenyl-(6,6)C61 (PCBM) doped with the soluble phthalocyanine derivative 1,4,8,11,15,18,22,25-octahexylphthalocyanine (C6PcH2). The photocurrent density was increased by 45% and the power conversion efficiency was improved to 3.9% by annealing at 130 °C. The annealing temperature dependence of the photovoltaic properties is discussed by considering the result of X-ray diffraction and photoluminescence measurements.

  6. Formation and Device Application of Ge Nanowire Heterostructures via Rapid Thermal Annealing

    OpenAIRE

    Tang, Jianshi; Wang, Chiu-Yen; Xiu, Faxian; Zhou, Yi; Chen, Lih-Juann; Wang, Kang L.

    2011-01-01

    We reviewed the formation of Ge nanowire heterostructure and its field-effect characteristics by a controlled reaction between a single-crystalline Ge nanowire and Ni contact pads using a facile rapid thermal annealing process. Scanning electron microscopy and transmission electron microscopy demonstrated a wide temperature range of 400~500°C to convert the Ge nanowire to a single-crystalline Ni2Ge/Ge/Ni2Ge nanowire heterostructure with atomically sharp interfaces. More importantly, we studie...

  7. Fast thermal annealing of implantation defects in silicon. Solid phase epitaxy and residual imperfection recovery

    International Nuclear Information System (INIS)

    Adekoya, O.A.

    1987-06-01

    Basic processes ruling the crystal reconstitution in solid phase during fast thermal annealing are studied; the role of electronic and thermodynamic effects at the interface is precised, following the implantations of a donor element (p + ), an acceptor element (B + ) and an intrinsic element (Ge + ). Then, after recrystallization, the electric role of residual point defects is shown together with the possibility of total recovery and an important electric activation of the doping [fr

  8. Effect of thermal annealing treatment with titanium chelate on buffer layer in inverted polymer solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Zhiyong [College of Science, Shenyang Agricultural University, Shenyang 110866 (China); Wang, Ning, E-mail: ning_wang@outlook.com [School of Electrical and Electronic and Engineering, Nanyang Technological University 639798 (Singapore); Fu, Yan, E-mail: 1060945062@qq.com [College of Science, Shenyang Agricultural University, Shenyang 110866 (China)

    2016-12-15

    Highlights: • The TIPD layer as electron extraction layer and instead of Ca or LiF. • Impact of the work function of TIPD layer by thermal annealing treatment. • Importance of TIPD layer as electron extraction layer for work function and potential barrier. - Abstract: The solution processable electron extraction layer (EEL) is crucial for polymer solar cells (PSCs). Here, we investigated titanium (diisopropoxide) bis(2,4-pentanedionate) (TIPD) as an EEL and fabricated inverted PSCs with a blend of poly(3-hexylthiophene) (P3HT) and indene-C60 bisadduct (ICBA) acting as the photoactive layer, with a structure of ITO/TIPD/P3HT:ICBA/MoO{sub 3}/Ag. After thermal annealing treatment at 150 °C for 15 min, the PSC performances increased from 3.85% to 6.84% and they achieve stable power conversion efficiency (PCE), with a similar PCE compared with TiO{sub 2} as an EEL by the vacuum evaporated method. Fourier transform infrared spectroscopy (FTIR) and ultraviolet photoelectron spectroscopy (UPS) confirmed that the TIPD decomposed and formed the Ti=O bond, and the energy level of the lowest unoccupied molecular orbital and the highest occupied molecular orbital increased. The space charge limited current (SCLC) measurements further confirmed the improvement in electron collection and the transport ability using TIPD as the EEL and thermal annealing.

  9. Effect of thermal annealing treatment with titanium chelate on buffer layer in inverted polymer solar cells

    International Nuclear Information System (INIS)

    Liu, Zhiyong; Wang, Ning; Fu, Yan

    2016-01-01

    Highlights: • The TIPD layer as electron extraction layer and instead of Ca or LiF. • Impact of the work function of TIPD layer by thermal annealing treatment. • Importance of TIPD layer as electron extraction layer for work function and potential barrier. - Abstract: The solution processable electron extraction layer (EEL) is crucial for polymer solar cells (PSCs). Here, we investigated titanium (diisopropoxide) bis(2,4-pentanedionate) (TIPD) as an EEL and fabricated inverted PSCs with a blend of poly(3-hexylthiophene) (P3HT) and indene-C60 bisadduct (ICBA) acting as the photoactive layer, with a structure of ITO/TIPD/P3HT:ICBA/MoO 3 /Ag. After thermal annealing treatment at 150 °C for 15 min, the PSC performances increased from 3.85% to 6.84% and they achieve stable power conversion efficiency (PCE), with a similar PCE compared with TiO 2 as an EEL by the vacuum evaporated method. Fourier transform infrared spectroscopy (FTIR) and ultraviolet photoelectron spectroscopy (UPS) confirmed that the TIPD decomposed and formed the Ti=O bond, and the energy level of the lowest unoccupied molecular orbital and the highest occupied molecular orbital increased. The space charge limited current (SCLC) measurements further confirmed the improvement in electron collection and the transport ability using TIPD as the EEL and thermal annealing.

  10. Cluster-assembled cubic zirconia films with tunable and stable nanoscale morphology against thermal annealing

    KAUST Repository

    Borghi, F.

    2016-08-05

    Nanostructured zirconium dioxide (zirconia) films are very promising for catalysis and biotechnological applications: a precise control of the interfacial properties of the material at different length scales and, in particular, at the nanoscale, is therefore necessary. Here, we present the characterization of cluster-assembled zirconia films produced by supersonic cluster beam deposition possessing cubic structure at room temperature and controlled nanoscale morphology. We characterized the effect of thermal annealing in reducing and oxidizing conditions on the crystalline structure, grain dimensions, and topography. We highlight the mechanisms of film growth and phase transitions, which determine the observed interfacial morphological properties and their resilience against thermal treatments. Published by AIP Publishing.

  11. Cluster-assembled cubic zirconia films with tunable and stable nanoscale morphology against thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Borghi, F.; Lenardi, C.; Podestà, A.; Milani, P., E-mail: pmilani@mi.infn.it [CIMAINA and Dipartimento di Fisica, Università degli Studi di Milano, via Celoria 16, 20133 Milano (Italy); Sogne, E. [CIMAINA and Dipartimento di Fisica, Università degli Studi di Milano, via Celoria 16, 20133 Milano (Italy); European School of Molecular Medicine (SEMM), IFOM-IEO, Milano (Italy); Merlini, M. [Dipartimento di Scienze della Terra “Ardito Desio”, Università degli Studi di Milano, via Mangiagalli 32, 20133 Milano (Italy); Ducati, C. [Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS (United Kingdom)

    2016-08-07

    Nanostructured zirconium dioxide (zirconia) films are very promising for catalysis and biotechnological applications: a precise control of the interfacial properties of the material at different length scales and, in particular, at the nanoscale, is therefore necessary. Here, we present the characterization of cluster-assembled zirconia films produced by supersonic cluster beam deposition possessing cubic structure at room temperature and controlled nanoscale morphology. We characterized the effect of thermal annealing in reducing and oxidizing conditions on the crystalline structure, grain dimensions, and topography. We highlight the mechanisms of film growth and phase transitions, which determine the observed interfacial morphological properties and their resilience against thermal treatments.

  12. Microstructural analysis of the thermal annealing of ice-Ih using EBSD

    Science.gov (United States)

    Hidas, Károly; Tommasi, Andréa; Mainprice, David; Chauve, Thomas; Barou, Fabrice; Montagnat, Maurine

    2017-04-01

    Rocks deformed in the middle crust and deeper in the Earth typically remain at high temperature for extended time spans after the cessation of deformation. This results in annealing of the deformation microstructure by a series of thermally activated, diffusion-based processes, namely: recovery and static recrystallization, which may also modify the crystal preferred orientation (CPO) or texture. Understanding the effects of annealing on the microstructure and CPO is therefore of utmost importance for the interpretation of the microstructures and for the estimation of the anisotropy of physical properties of lower crustal and mantle rocks. Ice-Ih -the typical form of water ice on the Earth's surface, with hexagonal crystal symmetry- deforms essentially by glide of dislocations on the basal plane [1], thus it has high viscoplastic anisotropy, which induces strong heterogeneity of stresses and strains at both the intra- and intergranular scales [2-3]. This behavior makes ice-Ih an excellent analog material for silicate minerals that compose the Earth. In situ observations of the evolution of the microstructures and CPO during annealing enable the study of the interplay between the various physical processes involved in annealing (recovery, nucleation, grain growth). They also allow the analysis of the impact of the preexisting deformation microstructures on the microstructural and CPO evolution during annealing. Here we studied the evolution of the microstructure of ice-Ih during static recrystallization by stepwise annealing experiments. We alternated thermal annealing and electron backscatter diffraction (EBSD) analyses on polycrystalline columnar ice-Ih pre-deformed in uniaxial compression at temperature of -7 °C to strains of 3.0-5.2. Annealing experiments were carried out at -5 °C and -2 °C up to a maximum of 3.25 days, typically in 5-6 steps. EBSD crystal orientation maps obtained after each annealing step permit the description of microstructural changes

  13. Nickel oxide films by thermal annealing of ion-beam-sputtered Ni: Structure and electro-optical properties

    Czech Academy of Sciences Publication Activity Database

    Horák, Pavel; Remeš, Zdeněk; Bejšovec, Václav; Vacík, Jiří; Daniš, S.; Kormunda, M.

    2017-01-01

    Roč. 640, č. 10 (2017), s. 52-59 ISSN 0040-6090 R&D Projects: GA ČR(CZ) GBP108/12/G108; GA ČR(CZ) GA14-05053S; GA MŠk LM2015056 Institutional support: RVO:61389005 ; RVO:68378271 Keywords : NiO * ion beam sputtering * thermal annealing * nuclear analytical methods * optical properties Subject RIV: JK - Corrosion ; Surface Treatment of Materials; BM - Solid Matter Physics ; Magnetism (FZU-D) OBOR OECD: Coating and films; Condensed matter physics (including formerly solid state physics, supercond.) (FZU-D) Impact factor: 1.879, year: 2016

  14. Influence of thermal annealing on the memory effect in MIS structures containing crystalline Si nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Meier, Sebastian; Brueggemann, R. [Institut fuer Physik, Carl von Ossietzky Universitaet Oldenburg, 26111 Oldenburg (Germany); Kirilov, Kiril [Department of Solid State Physics and Microelectronics, Sofia Univ. (Bulgaria); Levi, Zelma; Manolov, E. [Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee Blvd., 1784 Sofia (Bulgaria); Nedev, N. [Instituto de Ingenieria Universidad Autonoma de Baja California, Benito Juarez Blvd., s/n, C.P. 21280, Mexicali, Baja California, Mexico (Mexico)

    2007-07-01

    Silicon nanocrystals embedded in a SiO{sub 2} matrix are fabricated by thermal annealing of Metal/SiO{sub 2}/SiO{sub x}/c-Si structures (x=1.15) at 1000 C in N{sub 2} atmosphere for 30 or 60 min. High frequency C-V measurements demonstrate that both types of sample can be charged negatively or positively by applying a positive or negative bias voltage to the gate. The clockwise hysteresis windows of 30 and 60 min annealed samples are about 7 and 5.5 V for the {+-}12 V scanning range (E{sub ox}={+-}2.4 MV/cm), respectively. Although the samples annealed for 60 min have a smaller hysteresis window, they have two important advantages compared to the 30 min annealed ones: a lower defect density at the c-Si wafer/SiO{sub 2} interface and a smaller value of the fixed oxide charge close to this interface.

  15. Carrier Compensation Induced by Thermal Annealing in Al-Doped ZnO Films

    Directory of Open Access Journals (Sweden)

    Takashi Koida

    2017-02-01

    Full Text Available This study investigated carrier compensation induced by thermal annealing in sputtered ZnO:Al (Al2O3: 0.25, 0.5, 1.0, and 2.0 wt % films. The films were post-annealed in a N2 atmosphere at low (1 × 10−23 atm and high (1 × 10−4 atm oxygen partial pressures (PO2. In ZnO:Al films with low Al contents (i.e., 0.25 wt %, the carrier density (n began to decrease at annealing temperatures (Ta of 600 °C at low PO2. At higher PO2 and/or Al contents, n values began to decrease significantly at lower Ta (ca. 400 °C. In addition, Zn became desorbed from the films during heating in a high vacuum (i.e., <1 × 10−7 Pa. These results suggest the following: (i Zn interstitials and Zn vacancies are created in the ZnO lattice during post-annealing treatments, thereby leading to carrier compensation by acceptor-type Zn vacancies; (ii The compensation behavior is significantly enhanced for ZnO:Al films with high Al contents.

  16. Effect of thermal annealing on structural and optical properties of In2S3 thin films

    Science.gov (United States)

    Choudhary, Sonu

    2015-08-01

    There is a highly need of an alternate of toxic materials CdS for solar cell applications and indium sulfide is found the most suitable candidate to replace CdS due to its non-toxic and environmental friendly nature. In this paper, the effect of thermal annealing on the structural and optical properties of indium sulfide (In2S3) thin films is undertaken. The indium sulfide thin films of 121 nm were deposited on glass substrates employing thermal evaporation method. The films were subjected to the X-ray diffractometer and UV-Vis spectrophotometer respectively for structural and optical analysis. The XRD pattern show that the as-deposited thin film was amorphous in nature and crystallinity is found to be varied with annealing temperature. The optical analysis reveals that the optical band gap is varied with annealing. The optical parameters like absorption coefficient, extinction coefficient and refractive index were calculated. The results are in good agreement with available literature.

  17. Surface morphology evolution of amorphous Fe-Si layers upon thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Sun, C M; Tsang, H K; Wong, S P; Ke, N [Department of Electronic Engineering, Chinese University of Hong Kong, Shatin, NT, Hong Kong (China); Hark, S K [Department of Physics, Chinese University of Hong Kong, Shatin, NT, Hong Kong (China)], E-mail: cmsun@ee.cuhk.edu.hk

    2008-04-21

    Changes in the surface morphology of ion-beam-synthesized amorphous Fe-Si layers after rapid thermal annealing (RTA) and furnace annealing (FA) were investigated using atomic force microscopy and transmission electron microscopy. Completely amorphous Fe-Si layers were formed by Fe implantation at a dosage of 5 x 10{sup 15} cm{sup -2} using a metal vapour vacuum arc ion source under 80 kV extraction voltage and cryogenic temperature. After RTA at 850 deg. C, {beta}-FeSi{sub 2} precipitates in Si are completely aggregated from this amorphous Fe-Si layer and the surface of the implanted layer remains flat. To date, no obvious photoluminescence (PL) spectrum has been reported from RTA treated {beta}-FeSi{sub 2} precipitates. However, after annealing at 850 deg. C for 40 s, high-quality {beta}-FeSi{sub 2} precipitates in Si are obtained which clearly show 1.5 {mu}m PL at 80 K for the first time. Even though additional long-term FA at 850 deg. C can enhance PL intensity to a limited extent, the longer thermal treatment induces the outdiffusion of {beta}-FeSi{sub 2} precipitates and degrades the surface flatness.

  18. Thermal Annealing Reduces Geminate Recombination in TQ1:N2200 All-Polymer Solar Cells

    KAUST Repository

    Karuthedath, Safakath

    2018-03-27

    A combination of steady-state and time-resolved spectroscopic measurements is used to investigate the photophysics of the all-polymer bulk heterojunction system TQ1:N2200. Upon thermal annealing a doubling of the external quantum efficiency and an improved fill factor (FF) is observed, resulting in an increase in the power conversion efficiency. Carrier extraction is similar for both blends, as demonstrated by time-resolved electric-field-induced second harmonic generation experiments in conjunction with transient photocurrent studies, spanning the ps-µs time range. Complementary transient absorption spectroscopy measurements reveal that the different quantum efficiencies originate from differences in charge carrier separation and recombination at the polymer-polymer interface: in as-spun samples ~35 % of the charges are bound in interfacial charge-transfer states and recombine geminately, while this pool is reduced to ~7 % in thermally-annealed sample, resulting in higher short-circuit currents. Time-delayed collection field experiments demonstrate a field-dependent charge generation process in as-spun samples, which reduces the FF. In contrast, field-dependence of charge generation is weak in annealed films. While both devices exhibit significant non-geminate recombination competing with charge extraction, causing low FFs, our results demonstrate that the donor/acceptor interface in all-polymer solar cells can be favourably altered to enhance charge separation, without compromising charge transport and extraction.

  19. Thermal annealing of lattice-matched InGaAs/InAlAs Quantum-Cascade Lasers

    Science.gov (United States)

    Mathonnière, Sylvain; Semtsiv, M. P.; Ted Masselink, W.

    2017-11-01

    We describe the evolution of optical power, threshold current, and emission wavelength of a lattice-matched InGaAs/InAlAs Quantum-Cascade Laser (QCL) emitting at 13 μm grown by gas-source molecular-beam epitaxy under thermal annealing. Pieces from the same 2-in wafer were annealed at 600 °C, 650 °C, or 700 °C for 1 h; one control piece remained unannealed. No change in threshold current and emission wavelength was observed. The slope efficiency and maximum emission power increase for the 600 °C anneal, but higher annealing temperatures resulted in degraded performance. This result stands in contrast with the observation that strain-compensated structures cannot withstand annealing temperature of 600 °C. Useful information for post-growth processing steps and the role of interface roughness in QCL performance are obtained.

  20. Effects of rapid thermal annealing on the optical and electrical properties of InN epilayers

    International Nuclear Information System (INIS)

    Shu, G W; Wu, P F; Liu, Y W; Wang, J S; Shen, J L; Lin, T Y; Pong, P J; Chi, G C; Chang, H J; Chen, Y F; Lee, Y C

    2006-01-01

    We studied the optical and electrical properties of InN epilayers with rapid thermal annealing (RTA). The intensity of the photoluminescence (PL) and the carrier mobility were found to increase as the temperature of RTA was increased. We suggest that the formation of compensating acceptors (indium vacancies) after RTA is responsible for the improvement of the quality in InN. The dependence of the PL emission peak on carrier concentration provides a possible method for estimating the carrier concentration in degenerate InN. (letter to the editor)

  1. Defect annealing and thermal desorption of deuterium in low dose HFIR neutron-irradiated tungsten

    Energy Technology Data Exchange (ETDEWEB)

    Masashi Shimada; M. Hara; T. Otsuka; Y. Oya; Y. Hatano

    2014-05-01

    Accurately estimating tritium retention in plasma facing components (PFCs) and minimizing its uncertainty are key safety issues for licensing future fusion power reactors. D-T fusion reactions produce 14.1 MeV neutrons that activate PFCs and create radiation defects throughout the bulk of the material of these components. Recent studies show that tritium migrates and is trapped in bulk (>> 10 µm) tungsten beyond the detection range of nuclear reaction analysis technique [1-2], and thermal desorption spectroscopy (TDS) technique becomes the only established diagnostic that can reveal hydrogen isotope behavior in in bulk (>> 10 µm) tungsten. Radiation damage and its recovery mechanisms in neutron-irradiated tungsten are still poorly understood, and neutron-irradiation data of tungsten is very limited. In this paper, systematic investigations with repeated plasma exposures and thermal desorption are performed to study defect annealing and thermal desorption of deuterium in low dose neutron-irradiated tungsten. Three tungsten samples (99.99 at. % purity from A.L.M.T. Co., Japan) irradiated at High Flux Isotope Reactor at Oak Ridge National Laboratory were exposed to high flux (ion flux of (0.5-1.0)x1022 m-2s-1 and ion fluence of 1x1026 m-2) deuterium plasma at three different temperatures (100, 200, and 500 °C) in Tritium Plasma Experiment at Idaho National Laboratory. Subsequently, thermal desorption spectroscopy (TDS) was performed with a ramp rate of 10 °C/min up to 900 °C, and the samples were annealed at 900 °C for 0.5 hour. These procedures were repeated three (for 100 and 200 °C samples) and four (for 500 °C sample) times to uncover damage recovery mechanisms and its effects on deuterium behavior. The results show that deuterium retention decreases approximately 90, 75, and 66 % for 100, 200, and 500 °C, respectively after each annealing. When subjected to the same TDS recipe, the desorption temperature shifts from 800 °C to 600 °C after 1st annealing

  2. Implications of Thermal Annealing on the Benzene Vapor Sensing Behavior of PEVA-Graphene Nanocomposite Threads.

    Science.gov (United States)

    Patel, Sanjay V; Cemalovic, Sabina; Tolley, William K; Hobson, Stephen T; Anderson, Ryan; Fruhberger, Bernd

    2018-02-14

    The effect of thermal treatments, on the benzene vapor sensitivity of polyethylene (co-)vinylacetate (PEVA)/graphene nanocomposite threads, used as chemiresistive sensors, was investigated using DC resistance measurements, differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). These flexible threads are being developed as low-cost, easy-to-measure chemical sensors that can be incorporated into smart clothing or disposable sensing patches. Chemiresistive threads were solution-cast or extruded from PEVA and vapor in dry air. In addition, annealing increased the speed of response and recovery upon exposure to and removal of benzene vapor. DSC results showed that the presence of graphene raises the freezing point, and may allow greater crystallinity, in the nanocomposite after annealing. SEM images confirm increased surface roughness/area, which may account for the increase response speed after annealing. Benzene vapor detection at 5 ppm is demonstrated with limits of detection estimated to be as low as 1.5 ppm, reflecting an order of magnitude improvement over unannealed threads.

  3. Influence of Thermal Annealing on the Microstructural Properties of Indium Tin Oxide Nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sung Nam; Kim, Seung Bin [Pohang University of Science and Technology, Pohang (Korea, Republic of); Choi, Hyun Chul [Chonnam National University, Gwangju (Korea, Republic of)

    2012-01-15

    In this work, we studied the microstructural changes of ITO during the annealing process. ITO nanoparticles were prepared by the sol-gel method using indium tin hydroxide as the precursor. The prepared sample was investigated using TEM, powder XRD, XPS, DRIFT, and 2D correlation analysis. The O 1s XPS spectra suggested that the microstructural changes during the annealing process are closely correlated with the oxygen sites of the ITO nanoparticles. The temperature-dependent in situ DRIFT spectra suggested that In-OH in the terminal sites is firstly decomposed and, then, Sn-O-Sn is produced in the ITO nanoparticles during the thermal annealing process. Based on the 2D correlation analysis, we deduced the following sequence of events: 1483 (due to In-OH bending mode) → 2268, 2164 (due to In-OH stretching mode) → 1546 (due to overtones of Sn- O-Sn modes) → 1412 (due to overtones of Sn-O-Sn modes) cm{sup -1}.

  4. Highly Efficient Organic UV Photodetectors Based on Polyfluorene and Naphthalenediimide Blends: Effect of Thermal Annealing

    Directory of Open Access Journals (Sweden)

    Gorkem Memisoglu

    2012-01-01

    Full Text Available A solution-processed organic ultraviolet photodetector (UV-PD is introduced. The active layer of the UV-PD consists of poly(9,9-dioctyl fluorenyl-2,7–yleneethynylene (PFE and N,N′-bis-n-butyl-1,4,5,8- naphthalenediimide (BNDI with a weight ratio of 3 : 1 in chloroform. The effect of thermal annealing on the device properties was investigated from room temperature to 80∘C. The full device structure of ITO/PEDOT:PSS/PFE:BNDI (3 : 1/Al gave responsivity of 410 mA/W at −4 V under 1 mW/cm2 UV light at 368 nm when 60∘C of annealing temperature was used during its preparation. The devices that were annealed over the crystallization temperature of PFE showed a charge transfer resistance increase and a mobility decrease.

  5. Interpretation of microstructure evolution during self-annealing and thermal annealing of nanocrystalline electrodeposits—A comparative study

    DEFF Research Database (Denmark)

    Pantleon, Karen; Somers, Marcel A. J.

    2010-01-01

    Electrodeposition results in a non-equilibrium state of the as-deposited nanocrystalline microstructure, which evolves towards an energetically more favorable state as a function of time and/or temperature upon deposition. Real-time investigation of the evolving microstructure in copper, silver......-annealing kinetics of copper and silver electrodeposits as well as the annealing kinetics of electrodeposited nickel. Similarities and characteristic differences of the kinetics and mechanisms of microstructure evolution in the various electrodeposits are discussed and the experimental results are attempted...... and nickel electrodeposits was achieved by time-resolved X-ray diffraction line profile analysis and crystallographic texture analysis during room temperature storage and during isothermal annealing at elevated temperatures. These in-situ studies with unique time resolution allowed quantification of the self...

  6. Evolution of the microstructure, residual stresses, and mechanical properties of W-Si-N coatings after thermal annealing

    NARCIS (Netherlands)

    Cavaleiro, A; Marques, AP; Fernandes, JV; Carvalho, NJM; De Hosson, JT

    W-Si-N films were deposited by reactive sputtering in a Ar + N-2 atmosphere from a W target encrusted with different number of Si pieces and followed by a thermal annealing at increasing temperatures up to 900 degrees C. Three iron-based substrates with different thermal expansion coefficients, in

  7. Thermal annealing study on P3HT: PCBM based bulk heterojunction organic solar cells using impedance spectroscopy

    International Nuclear Information System (INIS)

    Gollu, Sankara Rao; Sharma, Ramakant; G, Srinivas; Gupta, Dipti

    2014-01-01

    Recently, Thermal annealing is an important process for bulk heterojunction organic solar cells (BHJ OSCs) to improve the device efficiency and performance of the organic solar cells. Here in, we have examined the changes in the efficiency and morphology of P3HT: PCBM film according to the thermal annealing temperature to find the changes during the annealing process by measuring the optical absorption, atomic force microscope and X-ray diffraction. We also investigated the effect of different annealing process conditions (without, pre- and post-annealing) on the device performance of the inverted bulk heterojunction organic solar cells consist the structure of ITO/ ZnO / P3HT: PCBM / MoO 3 / Al by measuring AC impedance characteristics. Particularly, the power conversion efficiency (PCE), crystalline nature of the polymer, light absorption and the surface smoothness of P3HT: PCBM films are significantly improved after the annealing process. These results indicated the improvement in terms of PCE, interface smoothness between the P3HT: PCBM and MoO 3 layers of the post annealed device originated from the decrease of series resistance between P3HT: PCBM layer and Al electrodes, which could be due to decrease in the effective life time of charge carriers

  8. Compositional evolution of Pd-based nanoclusters under thermal annealing in ion implanted SiO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Mattei, G. E-mail: mattei@padova.infm.it; Battaglin, G.; Bello, V.; Cattaruzza, E.; De Julian, C.; De Marchi, G.; Maurizio, C.; Mazzoldi, P.; Parolin, M.; Sada, C

    2004-06-01

    Sequential ion implantation has been used to synthesize Pd-based alloy nanoclusters in SiO{sub 2}. Three systems have been investigated (PdCu, PdAg and PdFe) in terms of nanocluster formation and stability under thermal annealing. In particular, we focused on the role played by the annealing atmosphere. A comparison is made with similar alloy-based systems obtained by sequential ion implantation in silica of Au-Ag or Au-Cu followed by annealing under similar conditions. Strong similarities have been found in the compositional evolution of Pd-based and Au-based nanoclusters.

  9. Origin of two maxima in specific heat in enthalpy relaxation under thermal history composed of cooling, annealing, and heating.

    Science.gov (United States)

    Sakatsuji, Waki; Konishi, Takashi; Miyamoto, Yoshihisa

    2016-12-01

    The origin of two maxima in specific heat observed at the higher and the lower temperatures in the glass-transition region in the heating process has been studied for polymethyl methacrylate and polyvinyl chloride using differential scanning calorimetry, and the calculation was done using the phenomenological model equation under a thermal history of the typical annealing experiment composed of cooling, annealing, and heating. The higher maximum is observed above the glass-transition temperature, and it remains almost unchanged independent of annealing time t_{a}, while the lower one is observed above an annealing temperature T_{a} and shifts toward the higher one, increasing its magnitude with t_{a}. The analysis by the phenomenological model equation proposed in order to interpret the memory effect in the glassy state clarifies that under a typical annealing history, two maxima in specific heat essentially appear. The shift of the lower maximum toward higher temperatures from above T_{a} is caused by an increase in the amount of relaxation during annealing with t_{a}. The annealing temperature and the amount of relaxation during annealing play a major role in the determination of the number of maxima in the specific heat.

  10. Thermal properties and structure of cast carbon-containing invar and superinvar alloys after two-stage annealing

    Science.gov (United States)

    Grachev, S. V.; Filippov, M. A.; Chermenskii, V. I.; Kharchuk, M. D.; Konchakovskii, I. V.; Zhilin, A. S.; Tokarev, V. V.; Nikiforova; S. M.

    2013-07-01

    The effect of carbon content on thermal properties of cast superinvar alloys subjected to two-stage annealing is studied. It is shown that carbon improves the casting properties of the alloys but raises the temperature coefficient of linear expansion (CTLE). Two-stage high-temperature annealing makes it possible to remove carbon from the solid solution and to transfer it into graphite, which is accompanied by decrease in the CTLE.

  11. Thermal annealing and pressure effects on BaFe2-xCoxAs2 single crystals.

    Science.gov (United States)

    Shin, Dongwon; Jung, Soon-Gil; Prathiba, G; Seo, Soonbeom; Choi, Ki-Young; Kim, Kee Hoon; Park, Tuson

    2017-11-26

    We investigate the pressure and thermal annealing effects on BaFe2-xCoxAs2 (Co-Ba122) single crystals with x = 0.1 and 0.17 via electrical transport measurements. The thermal annealing treatment not only enhances the superconducting transition temperature (Tc) from 9.6 to 12.7 K for x = 0.1 and from 18.1 to 21.0 K for x = 0.17, but also increases the antiferromagnetic transition temperature (TN). Simultaneous enhancement of Tc and TN by the thermal annealing treatment indicates that thermal annealing could substantially improve the quality of the Co-doped Ba122 samples. Interestingly, Tc of the Co-Ba122 compounds shows a scaling behavior with a linear dependence on the resistivity value at 290 K, irrespective of tuning parameters, such as chemical doping, pressure, and thermal annealing. These results not only provide an effective way to access the intrinsic properties of the BaFe2As2 system, but also may shed a light on designing new materials with higher superconducting transition temperature. © 2017 IOP Publishing Ltd.

  12. Thermal annealing and pressure effects on BaFe2-xCoxAs2single crystals.

    Science.gov (United States)

    Shin, Dongwon; Jung, Soon-Gil; Prathiba, G; Seo, Soonbeom; Choi, Ki-Young; Kim, Kee Hoon; Park, Tuson

    2017-12-08

    We investigate the pressure and thermal annealing effects on BaFe 2-x Co x As 2 (Co-Ba122) single crystals with x  =  0.1 and 0.17 via electrical transport measurements. The thermal annealing treatment not only enhances the superconducting transition temperature (T c ) from 9.6 to 12.7 K for x  =  0.1 and from 18.1 to 21.0 K for x  =  0.17, but also increases the antiferromagnetic transition temperature (T N ). Simultaneous enhancement of T c and T N by the thermal annealing treatment indicates that thermal annealing could substantially improve the quality of the Co-doped Ba122 samples. Interestingly, T c of the Co-Ba122 compounds shows a scaling behavior with a linear dependence on the resistivity value at 290 K, irrespective of tuning parameters such as chemical doping, pressure, and thermal annealing. These results not only provide an effective way to access the intrinsic properties of the BaFe 2 As 2 system, but may also shed a light on designing new materials with higher superconducting transition temperature.

  13. Field emission behavior of carbon nanotube field emitters after high temperature thermal annealing

    Directory of Open Access Journals (Sweden)

    Yuning Sun

    2014-07-01

    Full Text Available The carbon nanotube (CNT field emitters have been fabricated by attaching a CNT film on a graphite rod using graphite adhesive material. The CNT field emitters showed much improved field emission properties due to increasing crystallinity and decreasing defects in CNTs after the high temperature thermal annealing at 900 °C in vacuum ambient. The CNT field emitters showed the low turn-on electric field of 1.15 V/μm, the low threshold electric field of 1.62 V/μm, and the high emission current of 5.9 mA which corresponds to a current density of 8.5 A/cm2. In addition, the CNT field emitters indicated the enhanced field emission properties due to the multi-stage effect when the length of the graphite rod increases. The CNT field emitter showed good field emission stability after the high temperature thermal annealing. The CNT field emitter revealed a focused electron beam spot without any focusing electrodes and also showed good field emission repeatability.

  14. Effect of thermal annealing treatment with titanium chelate on buffer layer in inverted polymer solar cells

    Science.gov (United States)

    Liu, Zhiyong; Wang, Ning; Fu, Yan

    2016-12-01

    The solution processable electron extraction layer (EEL) is crucial for polymer solar cells (PSCs). Here, we investigated titanium (diisopropoxide) bis(2,4-pentanedionate) (TIPD) as an EEL and fabricated inverted PSCs with a blend of poly(3-hexylthiophene) (P3HT) and indene-C60 bisadduct (ICBA) acting as the photoactive layer, with a structure of ITO/TIPD/P3HT:ICBA/MoO3/Ag. After thermal annealing treatment at 150 °C for 15 min, the PSC performances increased from 3.85% to 6.84% and they achieve stable power conversion efficiency (PCE), with a similar PCE compared with TiO2 as an EEL by the vacuum evaporated method. Fourier transform infrared spectroscopy (FTIR) and ultraviolet photoelectron spectroscopy (UPS) confirmed that the TIPD decomposed and formed the Tidbnd O bond, and the energy level of the lowest unoccupied molecular orbital and the highest occupied molecular orbital increased. The space charge limited current (SCLC) measurements further confirmed the improvement in electron collection and the transport ability using TIPD as the EEL and thermal annealing.

  15. Effect of thermal annealing on a novel polyamide–imide polymer membrane for aggressive acid gas separations

    KAUST Repository

    Vaughn, Justin T.

    2012-05-01

    A fluorinated, 6FDA based polyamide-imide is investigated for the purification of CH 4 from CO 2 and H 2S containing gas streams. Dense polymer films were thermally annealed and showed that increased annealing temperatures at constant annealing time caused transport behavior that does not resemble physical aging. Free volume increased after annealing at 200°C for 24h relative to annealing at 150°C for the same time. CO 2 and CH 4 permeabilities and diffusivities did not decrease as a result of the higher annealing temperature, and in fact, were shown to increase slightly. A change to the intrinsic microstructure that cannot be described by simple, densification based physical aging is hypothesized to be the reason for this trend. Furthermore, annealing increased CO 2 induced plasticization resistance and a temperature of 200°C was shown to have the greatest effect on plasticization suppression. Annealing at 200°C for 24h suppressed pure gas CO 2 plasticization up to 450psia. Fluorescence spectroscopy revealed increased intramolecular charge transfer, which is presumably due to increased electron conjugation over the N-phenyl bond. Additionally, intermolecular charge transfer increased with thermal annealing, as inferred from fluorescence intensity measurements and XRD patterns. 50/50 CO 2/CH 4 mixed gas permeation measurements reveal stable separation performance up to 1000psia. Ternary mixed gas feeds containing toluene/CO 2/CH 4 and H 2S/CO 2/CH 4 show antiplasticization, but more importantly, selectivity losses due to plasticization did not occur up to 900psia of total feed pressure. These results show that the polyamide-imide family represents a promising class of separation materials for aggressive acid gas purifications. © 2012 Elsevier B.V.

  16. Low thermal budget annealing technique for high performance amorphous In-Ga-ZnO thin film transistors

    Directory of Open Access Journals (Sweden)

    Joong-Won Shin

    2017-07-01

    Full Text Available In this paper, we investigate a low thermal budget post-deposition-annealing (PDA process for amorphous In-Ga-ZnO (a-IGZO oxide semiconductor thin-film-transistors (TFTs. To evaluate the electrical characteristics and reliability of the TFTs after the PDA process, microwave annealing (MWA and rapid thermal annealing (RTA methods were applied, and the results were compared with those of the conventional annealing (CTA method. The a-IGZO TFTs fabricated with as-deposited films exhibited poor electrical characteristics; however, their characteristics were improved by the proposed PDA process. The CTA-treated TFTs had excellent electrical properties and stability, but the CTA method required high temperatures and long processing times. In contrast, the fabricated RTA-treated TFTs benefited from the lower thermal budget due to the short process time; however, they exhibited poor stability. The MWA method uses a low temperature (100 °C and short annealing time (2 min because microwaves transfer energy directly to the substrate, and this method effectively removed the defects in the a-IGZO TFTs. Consequently, they had a higher mobility, higher on-off current ratio, lower hysteresis voltage, lower subthreshold swing, and higher interface trap density than TFTs treated with CTA or RTA, and exhibited excellent stability. Based on these results, low thermal budget MWA is a promising technology for use on various substrates in next generation displays.

  17. Annealing effect on thermal conductivity and microhardness of carbon nanotube containing Se80Te16Cu4 glassy composites

    Science.gov (United States)

    Upadhyay, A. N.; Tiwari, R. S.; Singh, Kedar

    2018-02-01

    This study deals with the effect of thermal annealing on structural/microstructural, thermal and mechanical behavior of pristine Se80Te16Cu4 and carbon nanotubes (CNTs) containing Se80Te16Cu4 glassy composites. Pristine Se80Te16Cu4, 3 and 5 wt%CNTs-Se80Te16Cu4 glassy composites are annealed in the vicinity of glass transition temperature to onset crystallization temperature (340–380 K). X-ray diffraction (XRD) pattern revealed formation of polycrystalline phases of hexagonal CuSe and trigonal selenium. The indexed d-values in XRD patterns are in well conformity with the d-values obtained after the indexing of the ring pattern of selected area electron diffraction pattern of TEM images. The SEM investigation exhibited that the grain size of the CNTs containing Se80Te16Cu4 glassy composites increased with increasing annealing temperature and decreased at further higher annealing temperature. Thermal conductivity, microhardness exhibited a substantial increase with increasing annealing temperature of 340–360 K and slightly decreases for 380 K. The variation of thermal conductivity and microhardness can be explained by cross-linking formation and voids reduction.

  18. Influence of Annealing on the Optical Parameters of In2S3 Thin Films Produced by Thermal Evaporation

    Science.gov (United States)

    Izadneshan, H.; Gremenok, V. F.

    2014-05-01

    In2S3 thin fi lms are grown on glass substrates by vacuum thermal evaporation followed by annealing in vacuum between 330 and 400 °C for different time durations. We have investigated the infl uence of the annealing parameters on the characteristics of thin fi lms. It is shown that thermal treatment changed the crystal structure and optical energy band gap of In2S3 thin fi lms. Two energy band gaps were determined for all the fi lms, one indirect and the other direct.

  19. Effect of rapid thermal annealing on InP1−xBix grown by molecular beam epitaxy

    International Nuclear Information System (INIS)

    Wu, X Y; Wang, K; Pan, W W; Wang, P; Li, Y Y; Song, Y X; Gu, Y; Yue, L; Xu, H; Zhang, Z P; Cui, J; Gong, Q; Wang, S M

    2015-01-01

    The effect of post-growth rapid thermal annealing on structural and optical properties of InP 1−x Bi x thin films was investigated. InPBi shows good thermal stability up to 500 °C and a modest improvement in photoluminescence (PL) intensity with an unchanged PL spectral feature. Bismuth outdiffusion from InPBi and strain relaxation are observed at about 600 °C. The InPBi sample annealed at 800 °C shows an unexpected PL spectrum with different energy transitions. (paper)

  20. Evaluation of system requirements and standards development for thermal annealing of reactor pressure vessels. Progress report, March-September 1982

    International Nuclear Information System (INIS)

    Server, W.L.

    1983-03-01

    The material property data on thermal annealing of reactor-pressure-vessel steels have been reviewed. The most-critical materials are high copper welds; the data indicate that close to full recovery of Charpy V-notch properties can be realized by annealing at 850 0 F for 1 week (168 hours). However, the variability and sparcity of annealing recovery data dictate appropriate surveillance and experimental test programs. Of particular concern are the actual fracture-toughness changes and the differences between test- and power-reactor conditions. A survey of pressurized-water-reactor vendors, architect engineers, and consultants has been performed to assess the feasibility of performing a thermal-annealing cycle to restore the beltline material properties to their original state. This survey also addressed the issue of whether or not an actual annealing demonstration should be performed. It is the consensus view of the industry that in-situ reactor-vessel annealing can be done, but several areas still need to be studied and the American Society of Mechanical Engineers' Boiler and Pressure Vessel Code guidelines need to be defined

  1. Formation and Device Application of Ge Nanowire Heterostructures via Rapid Thermal Annealing

    Directory of Open Access Journals (Sweden)

    Jianshi Tang

    2011-01-01

    Full Text Available We reviewed the formation of Ge nanowire heterostructure and its field-effect characteristics by a controlled reaction between a single-crystalline Ge nanowire and Ni contact pads using a facile rapid thermal annealing process. Scanning electron microscopy and transmission electron microscopy demonstrated a wide temperature range of 400~500°C to convert the Ge nanowire to a single-crystalline Ni2Ge/Ge/Ni2Ge nanowire heterostructure with atomically sharp interfaces. More importantly, we studied the effect of oxide confinement during the formation of nickel germanides in a Ge nanowire. In contrast to the formation of Ni2Ge/Ge/Ni2Ge nanowire heterostructures, a segment of high-quality epitaxial NiGe was formed between Ni2Ge with the confinement of Al2O3 during annealing. A twisted epitaxial growth mode was observed in both two Ge nanowire heterostructures to accommodate the large lattice mismatch in the NixGe/Ge interface. Moreover, we have demonstrated field-effect transistors using the nickel germanide regions as source/drain contacts to the Ge nanowire channel. Our Ge nanowire transistors have shown a high-performance p-type behavior with a high on/off ratio of 105 and a field-effect hole mobility of 210 cm2/Vs, which showed a significant improvement compared with that from unreacted Ge nanowire transistors.

  2. Thermal annealing effect on poly(3-hexylthiophene): fullerene:copper-phthalocyanine ternary photoactive layer.

    Science.gov (United States)

    Derouiche, H; Mohamed, A B

    2013-01-01

    We have fabricated poly(3-hexylthiophene) (P3HT)/copper phthalocyanine (CuPc)/fullerene (C60) ternary blend films. This photoactive layer is sandwiched between an indium tin oxide (ITO)/poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT/PSS) photoanode and a bathocuproine (BCP)/aluminium photocathode. The thin films have been characterized by atomic force microscope (AFM) and ultraviolet/visible spectroscopy in order to study the influence of P3HT doping on the morphological and optical properties of the photoactive layer. We have also compared the I-V characteristics of three different organic solar cells: ITO/PEDOT:PSS/CuPc₀.₅:C60₀.₅/BCP/Al and ITO/PEDOT:PSS/P3HT₀.₃:CuPc₀.₃:C60₀.₄/BCP/Al with and without annealing. Both structures show good photovoltaic behaviour. Indeed, the incorporation of P3HT into CuPc:C60 thin film improves all the photovoltaic characteristics. We have also seen that thermal annealing significantly improves the optical absorption ability and stabilizes the organic solar cells making it more robust to chemical degradation.

  3. Neutron, gamma ray and post-irradiation thermal annealing effects on power semiconductor switches

    International Nuclear Information System (INIS)

    Schwarze, G.E.; Frasca, A.J.

    1994-01-01

    The effects of neutrons and gamma rays on the electrical and switching characteristics of power semiconductor switches must be known and understood by the designer of the power conditioning, control, and transmission subsystem of space nuclear power systems. The SP-100 radiation requirements at 25 m from the nuclear source are a neutron fluence of 10 13 n/cm 2 and a gamma dose of 0.5 Mrads. Experimental data showing the effects of neutrons and gamma rays on the performance characteristics of power-type NPN Bipolar Junction Transistors (BJTs), Metal-Oxide-Semiconductor Field Effect Transistors (MOSFETs), and Static Induction Transistors (SITs) are given in this paper. These three types of devices were tested at radiation levels which met or exceeded the SP-100 requirements. For the SP-100 radiation requirements, the BJTs were found to be most sensitive to neutrons, the MOSFETs were most sensitive to gamma rays, and the SITs were only slightly sensitive to neutrons. Post-irradiation thermal anneals at 300 K and up to 425 K were done on these devices and the effectiveness of these anneals are also discussed

  4. Neutron, gamma ray and post-irradiation thermal annealing effects on power semiconductor switches

    Science.gov (United States)

    Schwarze, G. E.; Frasca, A. J.

    1991-01-01

    The effects of neutron and gamma rays on the electrical and switching characteristics of power semiconductor switches must be known and understood by the designer of the power conditioning, control, and transmission subsystem of space nuclear power systems. The SP-100 radiation requirements at 25 m from the nuclear source are a neutron fluence of 10(exp 13) n/sq cm and a gamma dose of 0.5 Mrads. Experimental data showing the effects of neutrons and gamma rays on the performance characteristics of power-type NPN Bipolar Junction Transistors (BJTs), Metal-Oxide-Semiconductor Field Effect Transistors (MOSFETs), and Static Induction Transistors (SITs) are presented. These three types of devices were tested at radiation levels which met or exceeded the SP-100 requirements. For the SP-100 radiation requirements, the BJTs were found to be most sensitive to neutrons, the MOSFETs were most sensitive to gamma rays, and the SITs were only slightly sensitive to neutrons. Post-irradiation thermal anneals at 300 K and up to 425 K were done on these devices and the effectiveness of these anneals are also discussed.

  5. Thermal Annealing Effect on Poly(3-hexylthiophene: Fullerene:Copper-Phthalocyanine Ternary Photoactive Layer

    Directory of Open Access Journals (Sweden)

    H. Derouiche

    2013-01-01

    Full Text Available We have fabricated poly(3-hexylthiophene (P3HT/copper phthalocyanine (CuPc/fullerene (C60 ternary blend films. This photoactive layer is sandwiched between an indium tin oxide (ITO/poly(3,4-ethylenedioxythiophene:poly(styrene sulfonate (PEDOT/PSS photoanode and a bathocuproine (BCP/aluminium photocathode. The thin films have been characterized by atomic force microscope (AFM and ultraviolet/visible spectroscopy in order to study the influence of P3HT doping on the morphological and optical properties of the photoactive layer. We have also compared the characteristics of three different organic solar cells: ITO/PEDOT:PSS/CuPc0.5:C600.5/BCP/Al and ITO/PEDOT:PSS/P3HT0.3:CuPc0.3:C600.4/BCP/Al with and without annealing. Both structures show good photovoltaic behaviour. Indeed, the incorporation of P3HT into CuPc:C60 thin film improves all the photovoltaic characteristics. We have also seen that thermal annealing significantly improves the optical absorption ability and stabilizes the organic solar cells making it more robust to chemical degradation.

  6. Characteristics of OMVPE grown GaAsBi QW lasers and impact of post-growth thermal annealing

    Science.gov (United States)

    Kim, Honghyuk; Guan, Yingxin; Babcock, Susan E.; Kuech, Thomas F.; Mawst, Luke J.

    2018-03-01

    Laser diodes employing a strain-compensated GaAs1-xBix/GaAs1-yPy single quantum well (SQW) active region were grown by organometallic vapor phase epitaxy (OMVPE). High resolution x-ray diffraction, room temperature photoluminescence, and real-time optical reflectance measurements during the OMVPE growth were used to find the optimum process window for the growth of the active region material. Systematic post-growth in situ thermal anneals of various lengths were carried out in order to investigate the impacts of thermal annealing on the laser device performance characteristics. While the lowest threshold current density was achieved after the thermal annealing for 30 min at 630 °C, a gradual decrease in the external differential quantum efficiency was observed as the annealing time increases. It was observed that the temperature sensitivities of the threshold current density increase while those of lasing wavelength and slope efficiency remain nearly constant with increasing annealing time. Z-contrast scanning transmission electron microscopic) analysis revealed inhomogeneous Bi distribution within the QW active region.

  7. Structural changes in nanocrystalline Bi2Te3/Bi2Se3 multilayer thin films caused by thermal annealing

    Science.gov (United States)

    Hamada, Jun; Takashiri, Masayuki

    2017-06-01

    To assess the performance of thermoelectric devices with nanostructured materials at high operating temperatures, we investigated the effects of structural changes on the thermoelectric properties of nanocrystalline bismuth telluride (Bi2Te3)/bismuth selenide (Bi2Se3) multilayer thin films caused by thermal annealing. Multilayer thin films with 12 and 48 layers were fabricated by radio-frequency magnetron sputtering. These thin films were then thermally annealed at temperatures ranging from 250 to 350 °C. As the annealing temperature increased, flake-like nanocrystals were grown in the 12- and 48-layer thin films. X-ray diffraction peaks from three alloys, which were determined to be Bi2Te3, Bi2Se3, and (Bi2Te3)0.4(Bi2Se3)0.6, were observed in the thin films. This indicates that Bi2Te3 and Bi2Se3 layers were not completely diffused mutually in this range of annealing temperature. The 12- and 48-layer thin films exhibited increases in both the electrical conductivity and the absolute value of the Seebeck coefficient at the annealing temperature of 300 °C. One possible explanation for this improvement is that the band structure is tuned by inducing strain during the variation of atomic composition in the multilayer thin films. As a result, the power factor was significantly improved by the thermal annealing. In particular, the maximum power factor reached 13.7 μW/(cm K2) in the 12-layer thin film at the annealing temperature of 350 °C. Therefore, we may conclude that if the multilayer thin films undergo structural changes at higher operating temperature (≈350 °C), thermoelectric devices composed of multilayer thin films are expected to exhibit suitable thermoelectric performance.

  8. SERS activity of Ag decorated nanodiamond and nano-β-SiC, diamond-like-carbon and thermally annealed diamond thin film surfaces.

    Science.gov (United States)

    Kuntumalla, Mohan Kumar; Srikanth, Vadali Venkata Satya Siva; Ravulapalli, Satyavathi; Gangadharini, Upender; Ojha, Harish; Desai, Narayana Rao; Bansal, Chandrahas

    2015-09-07

    In the recent past surface enhanced Raman scattering (SERS) based bio-sensing has gained prominence owing to the simplicity and efficiency of the SERS technique. Dedicated and continuous research efforts have been made to develop SERS substrates that are not only stable, durable and reproducible but also facilitate real-time bio-sensing. In this context diamond, β-SiC and diamond-like-carbon (DLC) and other related thin films have been promoted as excellent candidates for bio-technological applications including real time bio-sensing. In this work, SERS activities of nanodiamond, nano-β-SiC, DLC, thermally annealed diamond thin film surfaces were examined. DLC and thermally annealed diamond thin films were found to show SERS activity without any metal nanostructures on their surfaces. The observed SERS activities of the considered surfaces are explained in terms of the electromagnetic enhancement mechanism and charge transfer resonance process.

  9. Luminescence and Thermal Annealing of Sputtered Deposited - and Samarium-Doped Amorphous AlN Films

    Science.gov (United States)

    Maqbool, Muhammad

    Thin films of thulium- and samarium-doped AlN are deposited on silicon (111) substrates at 77 K by RF magnetron sputtering method. 200-400 nm thick films are grown at 100-200 watts RF power and 5-8 mTorr nitrogen, using a metal target of Al with Tm and Sm separately. X-rays diffraction results show that films are amorphous. Cathodoluminescence studies are performed at room temperature and two dominant peaks are observed in Tm at 467 nm from 1D2 → 3F4 transition and 480 nm from 1G4 to the ground state 3H6 transition. Other peaks in the visible region are obtained at 650 nm and 685 nm due to 1G4 → 3F4 and 1D2 → 3H4 transitions. Peaks in the ultraviolet and infrared region are also obtained at 371 nm and 802 nm as a result from 1D2 → 3H6 and 3H4 → 3H6 transition, respectively. Sm gives four peaks at 564 nm, 600 nm, 648 nm and 707 nm as a result of 4G5/2 → 6H5/2, 4G5/2 → 6H7/2, 4G5/2 → 6H9/2 and 4G5/2 → 6H11/2 transitions. Films are thermally annealed at 1200 K for half an hour in a nitrogen atmosphere. Thermal annealing enhances the intensity of luminescence.

  10. Fabrication of Ohmic contact on semi-insulating 4H-SiC substrate by laser thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Yue; Lu, Wu-yue; Wang, Tao; Chen, Zhi-zhan, E-mail: zzchen@shnu.edu.cn [Department of Physics, Shanghai Normal University, 100 Guilin Road, Shanghai 200234 (China)

    2016-06-14

    The Ni contact layer was deposited on semi-insulating 4H-SiC substrate by magnetron sputtering. The as-deposited samples were treated by rapid thermal annealing (RTA) and KrF excimer laser thermal annealing (LTA), respectively. The RTA annealed sample is rectifying while the LTA sample is Ohmic. The specific contact resistance (ρ{sub c}) is 1.97 × 10{sup −3} Ω·cm{sup 2}, which was determined by the circular transmission line model. High resolution transmission electron microscopy morphologies and selected area electron diffraction patterns demonstrate that the 3C-SiC transition zone is formed in the near-interface region of the SiC after the as-deposited sample is treated by LTA, which is responsible for the Ohmic contact formation in the semi-insulating 4H-SiC.

  11. Activated Carbon Fibers "Thickly Overgrown" by Ag Nanohair Through Self-Assembly and Rapid Thermal Annealing

    Science.gov (United States)

    Yan, Xuefeng; Xu, Sijun; Wang, Qiang; Fan, Xuerong

    2017-11-01

    Anisotropic nanomaterial-modified carbon fibers attract increasing attention because of their superior properties over traditional ones. In this study, activated carbon fibers (ACFs) "thickly overgrown" by Ag nanohair were prepared through self-assembly and rapid thermal annealing. Viscose fibers with well-dispersed silver nanoparticles (AgNPs) on surfaces were first prepared through self-assembly of hyperbranched poly(amino-amine) (HBPAA)-capped AgNPs on viscose surfaces. HBPAA endowed the AgNP surfaces with negative charges and abundant amino groups, allowing AgNPs to monodispersively self-assemble to fiber surfaces. Ag nanohair-grown ACFs were prepared by sequential pre-oxidation and carbonization. Because the carbonization furnace was open-ended, ACFs are immediately transferrable to the outside of the furnace. Therefore, the Ag liquid adsorbed by ACF pores squeezed out to form Ag nanowires through thermal contraction. FESEM characterization indicated that Ag nanohairs stood on ACF surface and grew from ACF caps. XPS and XRD characterization showed that Ag successfully assembled to fiber surfaces and retained its metallic state even after high-temperature carbonization. TG analysis suggested that Ag nanohair-grown ACFs maintained their excellent thermal stabilities. Finally, the fabricated ACFs showed excellent and durable antibacterial activities, and the developed method may provide a potential strategy for preparing metal nanowire-grown ACFs.

  12. A market based active/reactive dispatch including transformer taps and reactor and capacitor banks using Simulated Annealing

    International Nuclear Information System (INIS)

    Gomes, Mario Helder; Saraiva, Joao Tome

    2009-01-01

    This paper describes an optimization model to be used by System Operators in order to validate the economic schedules obtained by Market Operators together with the injections from Bilateral Contracts. These studies will be performed off-line in the day before operation and the developed model is based on adjustment bids submitted by generators and loads and it is used by System Operators if that is necessary to enforce technical or security constraints. This model corresponds to an enhancement of an approach described in a previous paper and it now includes discrete components as transformer taps and reactor and capacitor banks. The resulting mixed integer formulation is solved using Simulated Annealing, a well known metaheuristic specially suited for combinatorial problems. Once the Simulated Annealing converges and the values of the discrete variables are fixed, the resulting non-linear continuous problem is solved using Sequential Linear Programming to get the final solution. The developed model corresponds to an AC version, it includes constraints related with the capability diagram of synchronous generators and variables allowing the computation of the active power required to balance active losses. Finally, the paper includes a Case Study based on the IEEE 118 bus system to illustrate the results that it is possible to obtain and their interest. (author)

  13. A market based active/reactive dispatch including transformer taps and reactor and capacitor banks using Simulated Annealing

    Energy Technology Data Exchange (ETDEWEB)

    Gomes, Mario Helder [Departamento de Engenharia Electrotecnica, Instituto Politecnico de Tomar, Quinta do Contador, Estrada da Serra, 2300 Tomar (Portugal); Saraiva, Joao Tome [INESC Porto, Faculdade de Engenharia, Universidade do Porto, Campus da FEUP, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal)

    2009-06-15

    This paper describes an optimization model to be used by System Operators in order to validate the economic schedules obtained by Market Operators together with the injections from Bilateral Contracts. These studies will be performed off-line in the day before operation and the developed model is based on adjustment bids submitted by generators and loads and it is used by System Operators if that is necessary to enforce technical or security constraints. This model corresponds to an enhancement of an approach described in a previous paper and it now includes discrete components as transformer taps and reactor and capacitor banks. The resulting mixed integer formulation is solved using Simulated Annealing, a well known metaheuristic specially suited for combinatorial problems. Once the Simulated Annealing converges and the values of the discrete variables are fixed, the resulting non-linear continuous problem is solved using Sequential Linear Programming to get the final solution. The developed model corresponds to an AC version, it includes constraints related with the capability diagram of synchronous generators and variables allowing the computation of the active power required to balance active losses. Finally, the paper includes a Case Study based on the IEEE 118 bus system to illustrate the results that it is possible to obtain and their interest. (author)

  14. The Effect of Thermal Annealing on the Optical Properties of a-SiC:H Films Produced by DC Sputtering Methods: I

    Directory of Open Access Journals (Sweden)

    Lusitra Munisa

    2003-04-01

    Full Text Available Silicon Target Case. The effects of thermal annealing treatment on the optical properties of amorphous silicon carbon films deposited by silicon target in an argon, methane and hydrogen gas mixture have been studied using ultra violet-visible (uv-vis spectroscopy. Both n and α, and consequently the real and imaginary parts of the dielectric constant, show a considerable variation with subsequent annealing up to annealing temperature 500 °C, with the most rapid changes occurring for temperature 300 °C. The films tend denser as the annealing temperature increased up to 500°C. The optical gap improved slightly upon annealing, where as the disorder of the amorphous network reduced. The annealing treatment produces reorganization of the amorphous network since thermal annealing results in dissociation of hydrogenated bonds (Si-H and C-H.

  15. Thermal annealing and transient electronic excitations induced interfacial and magnetic effects on Pt/Co/Pt trilayer

    Science.gov (United States)

    Sehdev, Neeru; Medwal, Rohit; Malik, Rakesh; Kandasami, Asokan; Kanjilal, Dinakar; Annapoorni, S.

    2018-04-01

    Present study investigates the importance of thermal annealing and transient electronic excitations (using 100 MeV oxygen ions) in assisting the interfacial atomic diffusion, alloy composition, and magnetic switching field distributions in Pt/Co/Pt stacked trilayer. X-ray diffraction analysis reveals that thermal annealing results in the formation of the face centered tetragonal L1°CoPt phase. The Rutherford back scattering spectra shows a trilayer structure for as-deposited and as-irradiated films. Interlayer mixing on the thermally annealed films further improves by electronic excitations produced by high energy ion irradiation. Magnetically hard face centered tetragonal CoPt alloy retains its hard phase after ion irradiation and reveals an enhancement in the structural ordering and magnetic stability. Enhancement in the homogeneity of alloy composition and its correlation with the magnetic switching field is evident from this study. A detailed investigation of the contributing parameters shows that the magnetic switching behaviour varies with the type of thermal annealing, transient electronic excitations of ion beams and combination of these processes.

  16. Enhanced Formation of Si Nanocrystals in SiO2 by Light-Filtering Rapid Thermal Annealing

    Science.gov (United States)

    Chen, Xiaobo; Chen, Guangping

    2015-04-01

    In this work, silicon-rich oxide (SRO) films with designed thickness of 100 nm were deposited by a bipolar pulse and radio frequency magnetron co-sputtering. For comparison, the samples were then treated in a nitrogen atmosphere by conventional rapid thermal annealing (CRTA) or light-filtering rapid thermal annealing (LRTA) at 900-1100°C for 2 min. Raman spectra, grazing incident X-ray diffraction (XRD), transmission electron microscopy (TEM), Hall measurements, and current density-voltage measurements were carried out to analyze the microstructural and electrical properties of samples. Compared with the control sample using CRTA method, the crystalline volume fraction and number density of Si nanocrystals (SiNCs) in silicon oxide prepared by LRTA were greatly increased. The quantum effects of the short wave-length light (less than 800 nm) of these tungsten halogen lamps during the rapid thermal annealing process have negative effects on the formation of SiNCs in SiO2 films. SiNCs with crystal volume fraction of 73%, average size of 2.53 nm, and number density of 1.1 × 1012 cm-2 embedded in the amorphous SiO2 matrix can be formed by LRTA at 1100°C. Enhancement of more than one order of magnitude in conductivity and higher current density were obtained from the LRTA annealed sample compared to the CRTA annealed sample. The improvements in conductivity and current density were attributed to the high density SiNCs. Our results show that the LRTA method is a suitable annealing tool for the formation of SiNC in thin SiOx films.

  17. Time effects in the thermal annealing of Fe/V multilayers

    CERN Document Server

    Borges, J F M

    2003-01-01

    We report a study on the structural and magnetic properties of iron-vanadium thin films grown in multilayer form and mixed by thermal treatment. The multilayer samples were annealed at 610 deg. C for times ranging from 10 to 540 min. The samples were structurally characterized by means of x-ray diffraction (XRD) and by x-ray absorption spectroscopy (XAS). The magnetic characterization was carried out with a conventional alternating gradient magnetometer (AGM) and by conversion electron Moessbauer spectroscopy (CEMS). The XRD result for the as-deposited multilayer shows a high degree of crystallinity while the CEMS result suggests an abrupt interface, since no significant contribution from vanadium in iron is observed. After the thermal treatment, the results from XRD show a phase transformation of the disordered body-centred-cubic structure (alpha-phase) into a tetragonal structure (sigma-phase) and a subsequent return to the alpha-phase. This alpha-sigma-alpha oscillation is not reported in the literature av...

  18. Effects of Thermal Annealing on Structural and Magnetic Properties of Lithium Ferrite Nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Jovic, Natasa G.; Masadeh, Ahmad S.; Kremenovic, Aleksandar S.; Antic, Bratislav V.; Blanusa, Jovan L.; Cvjeticanin, Nikola D.; Goya, Gerardo F.; Antisari, Marco Vittori; Bozin, Emil S.; (FPC-Serbia); (MSU); (Zaragoza); (ENEA); (Columbia); (Vinca)

    2010-01-12

    Pure, crystalline, {approx}10 nm lithium ferrite phase (Li{sub 0.5}Fe{sub 2.5}O{sub 4}), was successfully synthesized at very low temperature using a modified combustion method. The crystal structure and microstructure evolution of this system upon annealing were monitored by a careful investigation of X-ray diffractograms collected on a synchrotron source. Comparative analysis of the results obtained from the full profile Rietveld method (in reciprocal space) and the pair distribution function method (in direct space) was carried out. Nanocrystalline samples exhibit similar crystal structure, on average, with a partial ordering of Li{sup +} and Fe{sup 3+} ions between octahedral 4b and 12d sites on the spinel crystal lattice (space group P4{sub 3}32). After annealing at 973 K, cation distribution changes to a completely ordered, resembling that which is seen in the bulk lithium ferrite. The PDF analysis reveals abnormally high values of oxygen atomic displacement parameters in tetrahedral 8c sites (O1) indicating a significant disordering of the O1 network and suggests migration of lithium ions from 4b sites to the outer layers of nanoparticles. Analysis of room temperature Moessbauer spectra has shown that the hyperfine field for Fe{sup 3+} ions in tetrahedral 8c sites is the most sensitive on increasing the particle size and improving the crystallinity. From the differential thermal analysis, it was found that a lower driving force is required to induce an order-disorder phase transition in nanocrystalline samples, compared to the bulk-like sample, presumably due to the higher crystal disordering in these samples.

  19. Effects of Thermal Annealing on Structural and Magnetic Properties of Lithium Ferrite Nanoparticles

    International Nuclear Information System (INIS)

    Jovic, Natasa G.; Masadeh, Ahmad S.; Kremenovic, Aleksandar S.; Antic, Bratislav V.; Blanusa, Jovan L.; Cvjeticanin, Nikola D.; Goya, Gerardo F.; Antisari, Marco Vittori; Bozin, Emil S.

    2009-01-01

    Pure, crystalline, ∼10 nm lithium ferrite phase (Li 0.5 Fe 2.5 O 4 ), was successfully synthesized at very low temperature using a modified combustion method. The crystal structure and microstructure evolution of this system upon annealing were monitored by a careful investigation of X-ray diffractograms collected on a synchrotron source. Comparative analysis of the results obtained from the full profile Rietveld method (in reciprocal space) and the pair distribution function method (in direct space) was carried out. Nanocrystalline samples exhibit similar crystal structure, on average, with a partial ordering of Li + and Fe 3+ ions between octahedral 4b and 12d sites on the spinel crystal lattice (space group P4 3 32). After annealing at 973 K, cation distribution changes to a completely ordered, resembling that which is seen in the bulk lithium ferrite. The PDF analysis reveals abnormally high values of oxygen atomic displacement parameters in tetrahedral 8c sites (O1) indicating a significant disordering of the O1 network and suggests migration of lithium ions from 4b sites to the outer layers of nanoparticles. Analysis of room temperature Moessbauer spectra has shown that the hyperfine field for Fe 3+ ions in tetrahedral 8c sites is the most sensitive on increasing the particle size and improving the crystallinity. From the differential thermal analysis, it was found that a lower driving force is required to induce an order-disorder phase transition in nanocrystalline samples, compared to the bulk-like sample, presumably due to the higher crystal disordering in these samples.

  20. In situ transmission electron microscopy analyses of thermally annealed self catalyzed GaAs nanowires grown by molecular beam epitaxy

    DEFF Research Database (Denmark)

    Ambrosini, S.; Wagner, Jakob Birkedal; Booth, Tim

    2011-01-01

    Self catalyzed GaAs nanowires grown on Si-treated GaAs substrates were studied with a transmission electron microscope before and after annealing at 600◦C. At room temperature the nanowires have a zincblende structure and are locally characterized by a high density of rotational twins and stackin...... faults. Selected area diffraction patterns and high-resolution transmission electron microscopy images show that nanowires undergo structural modifications upon annealing, suggesting a decrease of defect density following the thermal treatment....

  1. Nanocrystals formation and intense green emission in thermally annealed AlN:Ho films for microlaser cavities and photonic applications

    Science.gov (United States)

    Maqbool, Muhammad; Ali, Ghafar; Cho, Sung Oh; Ahmad, Iftikhar; Mehmood, Mazhar; Kordesch, Martin E.

    2010-08-01

    Plasma magnetron sputtered thin films of AlN:Ho deposited on flat silicon substrates and optical fiber were characterized and analyzed for structural changes after thermal annealing at 1173 K for 40 min, by atomic force microscopy (AFM). The films grown, at liquid nitrogen temperature, on silicon substrates were amorphous while those deposited around optical fiber were crystalline. The films were also investigated for any change in the luminescence when thermal activation was performed for 40 min in a nitrogen atmosphere. The AFM analysis identified the existence of crystalline structures in parts of the films after thermal annealing. The x-ray diffraction could not provide those results. The films around optical fiber were crystalline even deposited at liquid nitrogen temperature. Clearly, amorphous films are hard to achieve on smaller substrate size. Direct observation of green emission is possible with naked eye, when the thermally annealed films are studied under cathodoluminescence. The green emission occurs at 549 nm as a result from S52→I58 transition in Ho3+ that enhanced with thermal activation, making it a very useful candidate for photonic and optical devices applications.

  2. Non-Stoichiometric Amorphous Indium Selenide Thin Films as a Buffer Layer for CIGS Solar Cells with Various Temperatures in Rapid Thermal Annealing.

    Science.gov (United States)

    Yoo, Myoung Han; Kim, Nam-Hoon

    2016-05-01

    The conventional structure of most of copper indium gallium diselenide (Culn(1-x)Ga(x)Se2, CIGS) solar cells includes a CdS thin film as a buffer layer. Cd-free buffer layers have attracted great interest for use in photovoltaic applications to avoid the use of hazardous and toxic materials. The RF magnetron sputtering method was used with an InSe2 compound target to prepare the indium selenide precursor. Rapid thermal annealing (RTA) was conducted in ambient N2 gas to control the concentration of volatile Se from the precursor with a change in temperature. The nature of the RTA-treated indium selenide thin films remained amorphous under annealing temperatures of ≤ 700 degrees C. The Se concentration of the RTA-treated specimens demonstrated an opposite trend to the annealing temperature. The optical transmittance and band gap energies were 75.33% and 2.451-3.085 eV, respectively, and thus were suitable for the buffer layer. As the annealing temperature increased, the resistivity decreased by an order-of-magnitude from 10(4) to 10(1) Ω-cm. At lower Se concentrations, the conductivity abruptly changed from p-type to n-type without crystallite formation in the amorphous phase, with the carrier concentration in the order of 10(17) cm(-3).

  3. Effect of rapid thermal annealing and hydrogen plasma treatment on the microstructure and light-emission of silicon-rich oxide film

    CERN Document Server

    Wang Yong; Chen Chang Yong; Diao Hong Wei; Zhang Shi Bin; Xu Yan Yue; Kong Guang Lin; Liao Xian Bo

    2002-01-01

    Silicon-rich silicon oxide (SRSO) films are prepared by plasma-enhanced chemical vapor deposition method at the substrate temperature of 200 degree C. The effect of rapid thermal annealing and hydrogen plasma treatment on the microstructure and light-emission of SRSO films are investigated in detail using micro-Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy and photoluminescence (PL) spectra. It is found that the phase-separation degree of the films decreases with increasing annealing temperature from 300 to 600 degree C, which it increases with increasing annealing temperature from 600 to 900 degree C. The light-emission of the films are enhanced with increasing annealing temperature up to 500 degree C, while it is rapidly reduced when the annealing temperature exceeds 600 degree C. The peak position of the PL spectrum blue shifts by annealing at the temperature of 300 degree C, then it redshifts with further raising annealing temperature. The following hydrogen plasma treatment results i...

  4. One accelerated method for predicting thermal annealing effects in post-irradiation CMOS devices

    International Nuclear Information System (INIS)

    He Baoping; Zhou Heqin; Guo Hongxia; Luo Yinhong; Zhang Fengqi; Yao Zhibin

    2005-01-01

    A method for accelerated predictions of the long-term anneal effects was presented. In order to find the correspondence between two anneals time, our estimating conditions were that each isochronal step was equal to the duration of the isothermal anneal leading to the same level of charge detrapping. The long term isothermal behavior at 100 degree C and 24 degree C of the type CC4007 CMOS devices were predicted by using isochronal anneal data of 25-250 degree C and compared with an experimental isothermal. The authors note a good agreement between simulation and experiment. (authors)

  5. Rapid thermal annealing of sputter-deposited ZnO:Al films for microcrystalline Si thin-film solar cells

    Directory of Open Access Journals (Sweden)

    Hanajiri T.

    2012-06-01

    Full Text Available Rapid thermal annealing of sputter-deposited ZnO and Al-doped ZnO (AZO films with and without an amorphous silicon (a-Si capping layer was investigated using a radio-frequency (rf argon thermal plasma jet of argon at atmospheric pressure. The resistivity of bare ZnO films on glass decreased from 108 to 104–105 Ω cm at maximum surface temperatures Tmaxs above 650 °C, whereas the resistivity increased from 10-4 to 10-3–10-2Ω cm for bare AZO films. On the other hand, the resistivity of AZO films with a 30-nm-thick a-Si capping layer remained below 10-4Ω cm, even after TPJ annealing at a Tmax of 825 °C. The film crystallization of both AZO and a-Si layers was promoted without the formation of an intermixing layer. Additionally, the crystallization of phosphorous- and boron-doped a-Si layers at the sample surface was promoted, compared to that of intrinsic a-Si under the identical plasma annealing conditions. The TPJ annealing of n+-a-Si/textured AZO was applied for single junction n-i-p microcrystalline Si thin-film solar cells.

  6. Thermal annealing behavior of niobium-implanted {alpha}-Al{sub 2}O{sub 3} under reducing environment

    Energy Technology Data Exchange (ETDEWEB)

    Zeng Jianer; Naramoto, Hiroshi; Aoki, Yasushi; Yamamoto, Shunya; Gan Mingle; Takeshita, Hidefumi [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    1997-03-01

    Thermal annealing behavior is studied in {alpha}-Al{sub 2}O{sub 3} implanted with {sup 93}Nb{sup +} using RBS/channeling technique and optical absorption spectrometry. The samples with <0001> and <112-bar0> orientations are implanted with 300 keV and 400 keV {sup 93}Nb{sup +} ions. Thermal annealing under reducing environment (Ar+3%H{sub 2}) is employed in the temperature range from 600 to 1000degC to explore unusual materials phase. The annealing up to 1000degC for an hour does not show any essential change in RBS/channeling spectra in two kinds of samples but the significant decrease in the visible region is observed in optical absorption spectra. After annealing at 1000degC for 10 hours, the recovery of the lattice damage is detected by RBS/channeling analysis especially in (112-bar0) sample. In the optical absorption spectra, new absorption envelope appears in the ultraviolet region. The results are related to the formation of niobium metal fine particles, and the sharp distribution is realized especially in (0001) sample. (author)

  7. A Lumped Thermal Model Including Thermal Coupling and Thermal Boundary Conditions for High Power IGBT Modules

    DEFF Research Database (Denmark)

    Bahman, Amir Sajjad; Ma, Ke; Blaabjerg, Frede

    2018-01-01

    Detailed thermal dynamics of high power IGBT modules are important information for the reliability analysis and thermal design of power electronic systems. However, the existing thermal models have their limits to correctly predict these complicated thermal behavior in the IGBTs: The typically used...... thermal model based on one-dimensional RC lumps have limits to provide temperature distributions inside the device, moreover some variable factors in the real-field applications like the cooling and heating conditions of the converter cannot be adapted. On the other hand, the more advanced three......-dimensional thermal models based on Finite Element Method (FEM) need massive computations, which make the long-term thermal dynamics difficult to calculate. In this paper, a new lumped three-dimensional thermal model is proposed, which can be easily characterized from FEM simulations and can acquire the critical...

  8. Effect of substrate properties and thermal annealing on the resistivity of molybdenum thin films

    International Nuclear Information System (INIS)

    Schmid, U.; Seidel, H.

    2005-01-01

    In this study, the influence of substrate properties (e.g. roughness characteristics and chemical composition) on the electrical resistivity of evaporated molybdenum thin films is investigated as a function of varying parameters, such as film thickness (25-115 nm) and post-deposition annealing with temperatures up to T PDA = 900 deg. C. A thermally oxidized silicon wafer with very low surface roughness was used as one substrate type. In contrast, a low temperature co-fired ceramics substrate with a glass encapsulant printed in thick film technology is the representative for rough surface morphology. The electrical resistivity follows the prediction of the size effect up to T PDA = 600 deg. C independent of substrate nature. On the silicon-based substrate, the thickness-independent portion of the film resistivity ρ g in the 'as deposited' state is about 29 times higher than the corresponding bulk value for a mono-crystalline sample. Thin films of this refractory metal on the SiO 2 /Si substrate exhibit an average grain size of 4.9 nm and a negative temperature coefficient of resistivity (TCR). On the glass/ceramic-based substrate, however, ρ g is half the value as compared to that obtained on the SiO 2 /Si substrate and the TCR is positive

  9. Thermally induced phase transformation in multi-phase iron oxide nanoparticles on vacuum annealing

    Science.gov (United States)

    Anupama, A. V.; Keune, W.; Sahoo, B.

    2017-10-01

    The evolution of magnetic phases in multi-phase iron oxide nanoparticles, synthesized via the transferred arc plasma induced gas phase condensation method, was investigated by X-ray diffraction, vibrating sample magnetometry and 57Fe Mössbauer spectroscopy. The particles are proposed to be consisting of three different iron oxide phases: α-Fe2O3, γ-Fe2O3 and Fe3O4. These nanoparticles were exposed to high temperature (∼935 K) under vacuum (10-3 mbar He pressure), and the thermally induced phase transformations were investigated. The Rietveld refinement of the X-ray diffraction data corroborates the least-squares fitting of the transmission Mössbauer spectra in confirming the presence of Fe3O4, γ-Fe2O3 and α-Fe2O3 phases before the thermal treatment, while only Fe3O4 and α-Fe2O3 phases exist after thermal treatment. On thermal annealing in vacuum, conversion from γ-Fe2O3 to Fe3O4 and α-Fe2O3 was observed. Interestingly, we have observed a phase transformation occurring in the temperature range ∼498 K-538 K, which is strikingly lower than the phase transformation temperature of γ-Fe2O3 to α-Fe2O3 (573-623 K) in air. Combining the results of Rietveld refinement of X-ray diffraction patterns and Mössbauer spectroscopy, we have attributed this phase transformation to the phase conversion of a metastable "defected and strained" d-Fe3O4 phase, present in the as-prepared sample, to the α-Fe2O3 phase. Stabilization of the phases by controlling the phase transformations during the use of different iron-oxide nanoparticles is the key factor to select them for a particular application. Our investigation provides insight into the effect of temperature and chemical nature of the environment, which are the primary factors governing the phase stability, suitability and longevity of the iron oxide nanomaterials prepared by the gas-phase condensation method for various applications.

  10. Electrode Materials, Thermal Annealing Sequences, and Lateral/Vertical Phase Separation of Polymer Solar Cells from Multiscale Molecular Simulations

    KAUST Repository

    Lee, Cheng-Kuang

    2014-12-10

    © 2014 American Chemical Society. The nanomorphologies of the bulk heterojunction (BHJ) layer of polymer solar cells are extremely sensitive to the electrode materials and thermal annealing conditions. In this work, the correlations of electrode materials, thermal annealing sequences, and resultant BHJ nanomorphological details of P3HT:PCBM BHJ polymer solar cell are studied by a series of large-scale, coarse-grained (CG) molecular simulations of system comprised of PEDOT:PSS/P3HT:PCBM/Al layers. Simulations are performed for various configurations of electrode materials as well as processing temperature. The complex CG molecular data are characterized using a novel extension of our graph-based framework to quantify morphology and establish a link between morphology and processing conditions. Our analysis indicates that vertical phase segregation of P3HT:PCBM blend strongly depends on the electrode material and thermal annealing schedule. A thin P3HT-rich film is formed on the top, regardless of bottom electrode material, when the BHJ layer is exposed to the free surface during thermal annealing. In addition, preferential segregation of P3HT chains and PCBM molecules toward PEDOT:PSS and Al electrodes, respectively, is observed. Detailed morphology analysis indicated that, surprisingly, vertical phase segregation does not affect the connectivity of donor/acceptor domains with respective electrodes. However, the formation of P3HT/PCBM depletion zones next to the P3HT/PCBM-rich zones can be a potential bottleneck for electron/hole transport due to increase in transport pathway length. Analysis in terms of fraction of intra- and interchain charge transports revealed that processing schedule affects the average vertical orientation of polymer chains, which may be crucial for enhanced charge transport, nongeminate recombination, and charge collection. The present study establishes a more detailed link between processing and morphology by combining multiscale molecular

  11. Application of fast thermal annealing to ferrites treatment; Application du recuit thermique rapide au traitement des ferrites

    Energy Technology Data Exchange (ETDEWEB)

    Legros, R.

    1995-12-31

    Annealing of magneto-optic memory disks require very fast treatment not to damage glass substrate. This article relates the optimisation of process and the choice of the most suitable alloy. Thermal rise time is linear for 15 s, then a 5 s constant 1273 degree Kelvin step is applied, and then a cooling phase starting at switching off the twelve 1 kw lamps. The most suitable alloy is the one containing manganese additions. (D.L.) 18 refs.

  12. Influence of thermal annealing on microstructural, morphological, optical properties and surface electronic structure of copper oxide thin films

    Energy Technology Data Exchange (ETDEWEB)

    Akgul, Funda Aksoy, E-mail: fundaaksoy01@gmail.com [Department of Physics, Nigde University, 51240 Nigde (Turkey); Center for Solar Energy Research and Applications, Middle East Technical University, 06800 Ankara (Turkey); Akgul, Guvenc, E-mail: guvencakgul@gmail.com [Bor Vocational School, Nigde University, 51700 Nigde (Turkey); Center for Solar Energy Research and Applications, Middle East Technical University, 06800 Ankara (Turkey); Yildirim, Nurcan [Department of Physics Engineering, Ankara University, 06100 Ankara (Turkey); Department of Metallurgical and Materials Engineering, Middle East Technical University, 06800 Ankara (Turkey); Unalan, Husnu Emrah [Department of Metallurgical and Materials Engineering, Middle East Technical University, 06800 Ankara (Turkey); Center for Solar Energy Research and Applications, Middle East Technical University, 06800 Ankara (Turkey); Turan, Rasit [Department of Physics, Middle East Technical University, 06800 Ankara (Turkey); Center for Solar Energy Research and Applications, Middle East Technical University, 06800 Ankara (Turkey)

    2014-10-15

    In this study, effect of the post-deposition thermal annealing on copper oxide thin films has been systemically investigated. The copper oxide thin films were chemically deposited on glass substrates by spin-coating. Samples were annealed in air at atmospheric pressure and at different temperatures ranging from 200 to 600°C. The microstructural, morphological, optical properties and surface electronic structure of the thin films have been studied by diagnostic techniques such as X-ray diffraction (XRD), Raman spectroscopy, ultraviolet–visible (UV–VIS) absorption spectroscopy, field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). The thickness of the films was about 520 nm. Crystallinity and grain size was found to improve with annealing temperature. The optical bandgap of the samples was found to be in between 1.93 and 2.08 eV. Cupric oxide (CuO), cuprous oxide (Cu{sub 2}O) and copper hydroxide (Cu(OH){sub 2}) phases were observed on the surface of as-deposited and 600 °C annealed thin films and relative concentrations of these three phases were found to depend on annealing temperature. A complete characterization reported herein allowed us to better understand the surface properties of copper oxide thin films which could then be used as active layers in optoelectronic devices such as solar cells and photodetectors. - Highlights: • Effect of post-deposition annealing on copper oxide thin films was investigated. • Structural, optical, and electronic properties of the thin films were determined. • Oxidation states of copper oxide thin films were confirmed by XPS analysis. • Mixed phases of CuO and Cu{sub 2}O were found to coexist in copper oxide thin films.

  13. High-temperature stability of chemically vapor-deposited tungsten-silicon couples rapid thermal annealed in ammonia and argon

    International Nuclear Information System (INIS)

    Broadbent, E.K.; Morgan, A.E.; Flanner, J.M.; Coulman, B.; Sadana, D.K.; Burrow, B.J.; Ellwanger, R.C.

    1988-01-01

    A rapid thermal anneal (RTA) in an NH 3 ambient has been found to increase the thermal stability of W films chemically vapor deposited (CVD) on Si. W films deposited onto single-crystal Si by low-pressure CVD were rapid thermal annealed at temperatures between 500 and 1100 0 C in NH 3 and Ar ambients. The reactions were studied using Rutherford backscattering spectrometry, x-ray diffraction, Auger electron spectroscopy, transmission electron microscopy, and four-point resistivity probe. High-temperature (≥1000 0 C) RTA in Ar completely converted W into the low resistivity (31 μΩ cm) tetragonal WSi 2 phase. In contrast, after a prior 900 0 C RTA in NH 3 , N inclusion within the W film and at the W/Si interface almost completely suppressed the W-Si reaction. Detailed examination, however, revealed some patches of WSi 2 formed at the interface accompanied by long tunnels extending into the substrate, and some crystalline precipitates in the substrate close to the interface. The associated interfacial contact resistance was only slightly altered by the 900 0 C NH 3 anneal. The NH 3 -treated W film acted as a diffusion barrier in an Al/W/Si contact metallurgy up to at least 550 0 C, at which point some increase in contact resistance was measured

  14. High-temperature stability of chemically vapor-deposited tungsten-silicon couples rapid thermal annealed in ammonia and argon

    Energy Technology Data Exchange (ETDEWEB)

    Broadbent, E.K.; Morgan, A.E.; Flanner, J.M.; Coulman, B.; Sadana, D.K.; Burrow, B.J.; Ellwanger, R.C.

    1988-12-15

    A rapid thermal anneal (RTA) in an NH/sub 3/ ambient has been found to increase the thermal stability of W films chemically vapor deposited (CVD) on Si. W films deposited onto single-crystal Si by low-pressure CVD were rapid thermal annealed at temperatures between 500 and 1100 /sup 0/C in NH/sub 3/ and Ar ambients. The reactions were studied using Rutherford backscattering spectrometry, x-ray diffraction, Auger electron spectroscopy, transmission electron microscopy, and four-point resistivity probe. High-temperature (greater than or equal to1000 /sup 0/C) RTA in Ar completely converted W into the low resistivity (31 ..mu cap omega.. cm) tetragonal WSi/sub 2/ phase. In contrast, after a prior 900 /sup 0/C RTA in NH/sub 3/, N inclusion within the W film and at the W/Si interface almost completely suppressed the W-Si reaction. Detailed examination, however, revealed some patches of WSi/sub 2/ formed at the interface accompanied by long tunnels extending into the substrate, and some crystalline precipitates in the substrate close to the interface. The associated interfacial contact resistance was only slightly altered by the 900 /sup 0/C NH/sub 3/ anneal. The NH/sub 3/-treated W film acted as a diffusion barrier in an Al/W/Si contact metallurgy up to at least 550 /sup 0/C, at which point some increase in contact resistance was measured.

  15. A Large-Area Nanoplasmonic Sensor Fabricated by Rapid Thermal Annealing Treatment for Label-Free and Multi-Point Immunoglobulin Sensing

    Directory of Open Access Journals (Sweden)

    Hana Tzu-Han Lin

    2017-05-01

    Full Text Available Immunoglobulins are important biomarkers to evaluate the immune status or development of infectious diseases. To provide timely clinical treatments, it is important to continuously monitor the level of multiple immunoglobulins. Localized surface plasmon resonance (LSPR-based nanoplasmonic sensors have been demonstrated for multiplex immunoglobulins detection. However, the sensor fabrication process is usually slow and complicated, so it is not accessible for large-area and batch fabrication. Herein, we report a large-area (2 cm × 2 cm nanofabrication method using physical vapor deposition followed by a rapid thermal annealing treatment. To optimize the sensor performance, we systematically characterized three fabrication conditions, including (1 the deposition thickness; (2 the maximum annealing temperature, and (3 the annealing time. The corresponding absorbance spectrum profile and surface morphology of the nanostructures were observed by a UV-VIS spectrometer and atomic force microscopy. We then tested the sensitivity of the sensor using a glucose solution at different concentrations. The results showed that the sensor with 10 nm gold deposition thickness under 5-min 900 °C rapid thermal annealing can achieve the highest sensitivity (189 nm RIU−1. Finally, we integrated this nanoplasmonic sensor with a microchannel and a motorized stage to perform a 10-spot immunoglobulin detection in 50 min. Based on its real-time, dynamic and multi-point analyte detection capability, the nanoplasmonic sensor has the potential to be applied in high-throughput or multiplex immunoassay analysis, which would be beneficial for disease diagnosis or biomedical research in a simple and cost-effective platform.

  16. A Large-Area Nanoplasmonic Sensor Fabricated by Rapid Thermal Annealing Treatment for Label-Free and Multi-Point Immunoglobulin Sensing.

    Science.gov (United States)

    Lin, Hana Tzu-Han; Yang, Chuan-Kai; Lin, Chi-Chen; Wu, Albert Meng-Hsin; Wang, Lon A; Huang, Nien-Tsu

    2017-05-02

    Immunoglobulins are important biomarkers to evaluate the immune status or development of infectious diseases. To provide timely clinical treatments, it is important to continuously monitor the level of multiple immunoglobulins. Localized surface plasmon resonance (LSPR)-based nanoplasmonic sensors have been demonstrated for multiplex immunoglobulins detection. However, the sensor fabrication process is usually slow and complicated, so it is not accessible for large-area and batch fabrication. Herein, we report a large-area (2 cm × 2 cm) nanofabrication method using physical vapor deposition followed by a rapid thermal annealing treatment. To optimize the sensor performance, we systematically characterized three fabrication conditions, including (1) the deposition thickness; (2) the maximum annealing temperature, and (3) the annealing time. The corresponding absorbance spectrum profile and surface morphology of the nanostructures were observed by a UV-VIS spectrometer and atomic force microscopy. We then tested the sensitivity of the sensor using a glucose solution at different concentrations. The results showed that the sensor with 10 nm gold deposition thickness under 5-min 900 °C rapid thermal annealing can achieve the highest sensitivity (189 nm RIU -1 ). Finally, we integrated this nanoplasmonic sensor with a microchannel and a motorized stage to perform a 10-spot immunoglobulin detection in 50 min. Based on its real-time, dynamic and multi-point analyte detection capability, the nanoplasmonic sensor has the potential to be applied in high-throughput or multiplex immunoassay analysis, which would be beneficial for disease diagnosis or biomedical research in a simple and cost-effective platform.

  17. Recovery in dc and rf performance of off-state step-stressed AlGaN/GaN high electron mobility transistors with thermal annealing

    International Nuclear Information System (INIS)

    Kim, Byung-Jae; Hwang, Ya-Hsi; Ahn, Shihyun; Zhu, Weidi; Dong, Chen; Lu, Liu; Ren, Fan; Holzworth, M. R.; Jones, Kevin S.; Pearton, Stephen J.; Smith, David J.; Kim, Jihyun; Zhang, Ming-Lan

    2015-01-01

    The recovery effects of thermal annealing on dc and rf performance of off-state step-stressed AlGaN/GaN high electron mobility transistors were investigated. After stress, reverse gate leakage current and sub-threshold swing increased and drain current on-off ratio decreased. However, these degradations were completely recovered after thermal annealing at 450 °C for 10 mins for devices stressed either once or twice. The trap densities, which were estimated by temperature-dependent drain-current sub-threshold swing measurements, increased after off-state step-stress and were reduced after subsequent thermal annealing. In addition, the small signal rf characteristics of stressed devices were completely recovered after thermal annealing

  18. Improvement in Field Electron Emission Performance of Natural-Precursor-Grown Carbon Nanofibers by Thermal Annealing in Argon Atmosphere

    Science.gov (United States)

    Ghosh, Pradip; Zamri, Mohd; Ghosh, Debasish; Soga, Tetsuo; Jimbo, Takashi; Hashimoto, Shinobu; Ohashi, Shuho; Tanemura, Masaki

    2011-01-01

    Carbon nanofibers (CNFs) were grown on a graphite substrate by the spray pyrolysis of a botanical hydrocarbon, turpentine oil, using ferrocene as the catalyst and sulfur as the promoter. The as-grown CNFs were annealed at 450 °C for 30 min in an air, and then at 1800 °C in an argon atmosphere for 2 h. The annealed CNFs have better degree of crystallinity and reduced number of defects compared with the as-grown CNFs confirmed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, and thermogravimetric analysis. The as-grown and annealed CNFs were found to be effective electron emitters with turn-on fields of 3.2 and 2.1 V/µm, respectively. The improvement in field emission (FE) performance can be explained in terms of the higher degree of graphitization of the CNFs after thermal annealing. This improved FE performance of the natural precursor grown CNFs was comparable to the FE performance level attainable for the conventional carbon nanomaterials grown using petroleum products. Thus, it was considered that the use of petroleum products could be avoidable for CNF growth and that CNFs grown using ecofriendly materials are very promising for the application in future field emission displays (FEDs).

  19. Formation of vacancy and oxygen containing complexes in Cz-Si by rapid thermal annealing

    International Nuclear Information System (INIS)

    Akhmetov, V.; Kissinger, G.; Ammon, W. von

    2009-01-01

    Changes of the oxygen (O) state in Czochralski silicon (Cz Si) caused by rapid thermal annealing (RTA) were studied by means of Fourier transform infrared spectroscopy (FTIR) in a highly sensitive mode. The formation of vacancy (V) and O containing complexes VO 4 , previously known only from radiation experiments was observed as a result of RTA of Si wafers under clean room conditions without applying any irradiation. The use of half wafers during RTA processing and the use of the second untreated part of the same wafer as a reference during precise differential FTIR measurements allowed us to reveal, quite reproducibly, the small RTA induced changes in the absorbance in the level of ∼10 -5 in absorbance units. Special attention was paid to separate the real contribution from the bulk from a possible surface related contribution in the recorded differential absorbance spectra. As a result, the quantitatively reproducible vibrational absorption band 985 cm -1 at room temperature known of VO 4 was revealed in each of the examined wafers after RTA. The concentration of the observed complexes was approximately 1.4x10 13 cm -3 as estimated from the integrated calibration factor for interstitial oxygen (O i ). No traces of VO, VO 2 , VO 3 , VO 5 and VO 6 were found in a similar level. A moderate decrease, in the level of 10 13 -10 14 cm -3 , of the content of oxygen dimers (O 2i , 1012 cm -1 ) and trimers (O 3i , 1005 cm -1 ) in as-grown Si was observed after RTA. Changes in the concentration of O i did not exceed approximately 0.5%. Possible reasons for the preferential formation of VO 4 by RTA are briefly discussed.

  20. Study of the optical properties and the carbonaceous clusters in thermally-annealed CR-39 and Makrofol-E polymer-based solid-state nuclear track detectors

    International Nuclear Information System (INIS)

    El Ghazaly, M.

    2012-01-01

    The induced modifications in the optical properties of CR-39 and Makrofol-E polymer-based solid state nuclear track detectors were investigated after thermal annealing at a temperature of 200 .deg. C for different durations. The optical properties were studied using an UV-visible spectrophotometer. From the UV-visible spectra, the direct and the indirect optical band gaps, Urbach's energies, and the number of carbon atoms in a cluster were determined. The absorbance of CR-39 plastic detector was found to decrease with increasing annealing time while the absorbance of Makrofol-E decreased with increasing annealing time. The width of the tail of localized states in the band gap ΔE was evaluated with the Urbach method. The optical energy band gaps were obtained from the direct and the indirect allowed transitions in K-space. Both of the direct and the indirect band gaps of the annealed CR-39 detector decrease with increasing annealing time while in Makrofol-E, they decreased after an annealing time of 15 minute and then showed no remarkable changes for a prolonged annealing times. Urbach's energy decreased significantly for both CR-39 and Makrofol-E with increasing annealing time. The number of carbon atoms in a cluster increased in the CR-39 detector with increasing annealing time while it decreased with increasing annealing time for Makrofol-E. We may conclude that the CR-39 detector undergoes greater modifications than the Makrofol-E detector upon thermal annealing at 200 .deg. C. In conclusion, the induced modifications in the optical properties of CR-39 and Makrofol-E are correlated with the temperature and the duration of annealing.

  1. Thermal Annealing induced relaxation of compressive strain in porous GaN structures

    KAUST Repository

    Ben Slimane, Ahmed

    2012-01-01

    The effect of annealing on strain relaxation in porous GaN fabricated using electroless chemical etching is presented. The Raman shift of 1 cm-1 in phonon frequency of annealed porous GaN with respect to as-grown GaN corresponds to a relaxation of compressive strain by 0.41 ± 0.04 GPa. The strain relief promises a marked reduction in threading dislocation for subsequent epitaxial growth.

  2. Isothermal capacitance transient spectroscopy (ICTS) study for midgap levels in Hb-GaAs by rapid thermal annealing

    Science.gov (United States)

    Cho, Hoon Young; Kim, Eun Kyu; Min, Suk-Ki; Choh, Sung Ho

    1989-04-01

    We studied the midgap levels by using isothermal capacitance transient spectroscopy (ICTS) in Hb-GaAs which had been processed by rapid thermal annealing (RTA). As the annealing time at 850 °C increased, the EL2 trap ( E c-0.81 eV) was transformed to the EX2 trap ( E c-0.73 eV) and eventually to the EX1 trap ( E c-0.87 eV). The diffusivity of the EL2 trap obtained from the experimental result of the heat treatment was about 1.02·10-8cm2/s at 850 °C. This result indicate that the EL2 trap contains an interstitial arsenic atom. The result of the transformation to the EX1 and EX2 traps suggests that, when the EL2 trap is VAsASiVGaAsGa, the EX2 trap may be VAsVGaAsGa, which Asi is diffused out during a thermal annealing.

  3. An anti-bacterial approach to nanoscale roughening of biomimetic rice-like pattern PP by thermal annealing

    Science.gov (United States)

    Jafari Nodoushan, Emad; Ebrahimi, Nadereh Golshan; Ayazi, Masoumeh

    2017-11-01

    In this paper, we introduced thermal annealing treatment as an effective way of increasing the nanoscale roughness of a semi-crystalline polymer surface. Annealing treatment applied to a biomimetic microscale pattern of rice leaf to achieve a superhydrophobic surface with a hierarchical roughness. Resulted surfaces was characterized by XRD, AFM and FE-SEM instruments and showed an increase of roughness and cristallinity within both time and temperature of treatment. These two parameters also impact on measured static contact angle up to 158°. Bacterial attachment potency has an inverse relationship with the similarity of surface pattern dimensions and bacterial size and due to that, thermal annealing could be an effective way to create anti-bacterial surface beyond its effect on water repellency. Point in case, the anti-bacterial properties of produced water-repellence surfaces of PP were measured and counted colonies of both gram-negative (E. coli) and gram-positive (S. aureus) bacteria reduced with the nature of PP and hierarchical pattern on that. Anti-bacterial characterization of the resulted surface reveals a stunning reduction in adhesion of gram-positive bacteria to the surface. S. aureus reduction rates equaled to 95% and 66% when compared to control blank plate and smooth surface of PP. Moreover, it also could affect the other type of bacteria, gram-negative (E. coli). In the latter case, adhesion reduction rates calculated 66% and 53% when against to the same controls, respectively.

  4. Annealing Effect on the Thermoelectric Properties of Bi2Te3 Thin Films Prepared by Thermal Evaporation Method

    Directory of Open Access Journals (Sweden)

    Jyun-Min Lin

    2013-01-01

    Full Text Available Bismuth telluride-based compounds are known to be the best thermoelectric materials within room temperature region, which exhibit potential applications in cooler or power generation. In this paper, thermal evaporation processes were adopted to fabricate the n-type Bi2Te3 thin films on SiO2/Si substrates. The influence of thermal annealing on the microstructures and thermoelectric properties of Bi2Te3 thin films was investigated in temperature range 100–250°C. The crystalline structures and morphologies were characterized by X-ray diffraction and field emission scanning electron microscope analyses. The Seebeck coefficients, electrical conductivity, and power factor were measured at room temperature. The experimental results showed that both the Seebeck coefficient and power factor were enhanced as the annealing temperature increased. When the annealing temperature increased to 250°C for 30 min, the Seebeck coefficient and power factor of n-type Bi2Te3-based thin films were found to be about −132.02 μV/K and 6.05 μW/cm·K2, respectively.

  5. Current-induced metal-insulator transition in VO x thin film prepared by rapid-thermal-annealing

    International Nuclear Information System (INIS)

    Cho, Choong-Rae; Cho, SungIl; Vadim, Sidorkin; Jung, Ranju; Yoo, Inkyeong

    2006-01-01

    The phenomenon of metal-insulator transition (MIT) in polycrystalline VO x thin films and their preparations have been studied. The films were prepared by sputtering of vanadium thin films succeeded by Rapid Thermal Annealing (RTA) in oxygen ambient at 500 deg. C. Crystalline, compositional, and morphological characterizations reveal a continuous change of phase from vanadium metal to the highest oxide phase, V 2 O 5 , with the time of annealing. Electrical MIT switching has been observed in these films. Sweeping mode, electrode area, and temperature dependent MIT has been studied in Pt/VO x /Pt vertical structure. The important parameters for MIT in VO x have been found to be the current density and the electric field, which depend on carrier density in the films

  6. Diffusion of gold in silicon during rapid thermal annealing: Effectiveness of the surface as a sink for self-interstitials

    Science.gov (United States)

    Lerch, W.; Stolwijk, N. A.

    1998-02-01

    Rapid thermal annealing was used for short-time diffusion experiments of gold in dislocation-free floating-zone silicon of {100} orientation at 1050 °C and 1119 °C. Concentration-depth profiles measured by the spreading-resistance technique are well described within the framework of the kick-out mechanism involving generation of silicon self-interstitials. More specifically, the gold-incorporation rate appears to be controlled by the outdiffusion of excess self-interstitials towards the surfaces. As a special feature, the measurements reveal a continuous increase of the gold boundary concentration which approaches the pertaining solubility limit only after prolonged annealing. This can be interpreted in terms of a limited effectiveness of gold-alloyed {100} silicon surfaces as sinks for self-interstitials. The validity of this interpretation is supported by computer modeling of the experimental data yielding finite values for the self-interstitial surface-annihilation velocity.

  7. Evolution of interface and surface structures of ZnO/Al2 O3 multilayers upon rapid thermal annealing

    Science.gov (United States)

    Liu, H. H.; Chen, Q. Y.; Chang, C. F.; Hsieh, W. C.; Wadekar, P. V.; Huang, H. C.; Liao, H. H.; Seo, H. W.; Chu, W. K.

    2015-03-01

    ZnO ∖Al2O3 multilayers were deposited on sapphires by atomic layer deposition at 85°C. This low substrate temperature ensures good interface smoothness useful for study of interfacial reaction or interdiffusion. Our study aimed at the effects of rapid thermal annealing at different annealing temperatures, times and PAr:PO2. XRR and XRD techniques were used to investigate the kinetics from which various terms of the activation energies could be determined. HR-TEM and electron diffraction were carried out to correlate the microstructures and interfacial alignments as a result of the reactions. AFM were used to assist SEM profiling of the surface morphological evolution in association with the TEM observations.

  8. Pure thermal sensitisation and pre-dose effect of OSL in both unfired and annealed quartz samples

    Energy Technology Data Exchange (ETDEWEB)

    Oniya, Ebenezer O., E-mail: ebenezer.oniya@aaua.edu.ng [Physics and Electronics Department, Adekunle Ajasin University, 342111 Akungba Akoko (Nigeria); Polymeris, George S. [Institute of Nuclear Sciences, Ankara University, Beşevler 06100, Ankara (Turkey); Jibiri, Nnamdi N. [Department of Physics, University of Ibadan, Ibadan (Nigeria); Tsirliganis, Nestor C. [Department of Archaeometry and Physicochemical Measurements, R.C. ‘Athena’, P.O. Box 159, Kimmeria University Campus, 67100 Xanthi (Greece); Babalola, Israel A. [Department of Physics, University of Ibadan, Ibadan (Nigeria); Kitis, George [Nuclear Physics Laboratory, Department of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece)

    2017-06-01

    The sensitisation of quartz has attracted much attention since its thorough understanding is important in luminescence studies and dating applications. The present investigation examines the influence of pure thermal activation and predose treatments on the sensitisation of different components of linearly modulated optically stimulated luminescence (LM-OSL) measured at room temperature (RT) thereby eliminating undesired thermal quenching effects. Annealed and unfired quartz samples from Nigeria were used. The OSL measurements were carried out using an automated RISØTL/OSL reader (model-TL/OSL–DA–15). A new approach was adopted to match each of the resolved components of the RT-LM-OSL to respective thermoluminescence (TL) peaks that share the same electron trap and recombination centers. Pure thermal activation and pre-dose treatments respectively affect the sensitisation of all the components of the RT-LM-OSL in a similar manner as the one reported for the 110 °C TL peak but without thermal quenching contributions. Component C4 in annealed samples that was identified to share the same electron trap and recombination centers with the 110 °C TL peak was also proved appropriate for RT-LM-OSL, instead of the initial part of the continuous wave (CW) OSL signal, thus the methods can serve as complementary dating methods.

  9. Pure thermal sensitisation and pre-dose effect of OSL in both unfired and annealed quartz samples

    International Nuclear Information System (INIS)

    Oniya, Ebenezer O.; Polymeris, George S.; Jibiri, Nnamdi N.; Tsirliganis, Nestor C.; Babalola, Israel A.; Kitis, George

    2017-01-01

    The sensitisation of quartz has attracted much attention since its thorough understanding is important in luminescence studies and dating applications. The present investigation examines the influence of pure thermal activation and predose treatments on the sensitisation of different components of linearly modulated optically stimulated luminescence (LM-OSL) measured at room temperature (RT) thereby eliminating undesired thermal quenching effects. Annealed and unfired quartz samples from Nigeria were used. The OSL measurements were carried out using an automated RISØTL/OSL reader (model-TL/OSL–DA–15). A new approach was adopted to match each of the resolved components of the RT-LM-OSL to respective thermoluminescence (TL) peaks that share the same electron trap and recombination centers. Pure thermal activation and pre-dose treatments respectively affect the sensitisation of all the components of the RT-LM-OSL in a similar manner as the one reported for the 110 °C TL peak but without thermal quenching contributions. Component C4 in annealed samples that was identified to share the same electron trap and recombination centers with the 110 °C TL peak was also proved appropriate for RT-LM-OSL, instead of the initial part of the continuous wave (CW) OSL signal, thus the methods can serve as complementary dating methods.

  10. Cascade annealing: an overview

    International Nuclear Information System (INIS)

    Doran, D.G.; Schiffgens, J.O.

    1976-04-01

    Concepts and an overview of radiation displacement damage modeling and annealing kinetics are presented. Short-term annealing methodology is described and results of annealing simulations performed on damage cascades generated using the Marlowe and Cascade programs are included. Observations concerning the inconsistencies and inadequacies of current methods are presented along with simulation of high energy cascades and simulation of longer-term annealing

  11. Controlling Growth High Uniformity Indium Selenide (In2Se3) Nanowires via the Rapid Thermal Annealing Process at Low Temperature.

    Science.gov (United States)

    Hsu, Ya-Chu; Hung, Yu-Chen; Wang, Chiu-Yen

    2017-09-15

    High uniformity Au-catalyzed indium selenide (In 2 Se 3) nanowires are grown with the rapid thermal annealing (RTA) treatment via the vapor-liquid-solid (VLS) mechanism. The diameters of Au-catalyzed In 2 Se 3 nanowires could be controlled with varied thicknesses of Au films, and the uniformity of nanowires is improved via a fast pre-annealing rate, 100 °C/s. Comparing with the slower heating rate, 0.1 °C/s, the average diameters and distributions (standard deviation, SD) of In 2 Se 3 nanowires with and without the RTA process are 97.14 ± 22.95 nm (23.63%) and 119.06 ± 48.75 nm (40.95%), respectively. The in situ annealing TEM is used to study the effect of heating rate on the formation of Au nanoparticles from the as-deposited Au film. The results demonstrate that the average diameters and distributions of Au nanoparticles with and without the RTA process are 19.84 ± 5.96 nm (30.00%) and about 22.06 ± 9.00 nm (40.80%), respectively. It proves that the diameter size, distribution, and uniformity of Au-catalyzed In 2 Se 3 nanowires are reduced and improved via the RTA pre-treated. The systemic study could help to control the size distribution of other nanomaterials through tuning the annealing rate, temperatures of precursor, and growth substrate to control the size distribution of other nanomaterials. Graphical Abstract Rapid thermal annealing (RTA) process proved that it can uniform the size distribution of Au nanoparticles, and then it can be used to grow the high uniformity Au-catalyzed In 2 Se 3 nanowires via the vapor-liquid-solid (VLS) mechanism. Comparing with the general growth condition, the heating rate is slow, 0.1 °C/s, and the growth temperature is a relatively high growth temperature, > 650 °C. RTA pre-treated growth substrate can form smaller and uniform Au nanoparticles to react with the In 2 Se 3 vapor and produce the high uniformity In 2 Se 3 nanowires. The in situ annealing TEM is used to realize the effect of heating

  12. The effect of thermal annealing on the properties of Al2O3-films prepared by MOCVD at atmoshperic pressure

    NARCIS (Netherlands)

    Haanappel, V.A.C.; Haanappel, V.A.C.; van Corbach, H.D.; Fransen, T.; Gellings, P.J.

    1994-01-01

    Thin films deposited at 330°C by metal organic chemical vapour deposition on stainless steel, type AISI 304, were annealed in a nitrogen atmosphere for 1, 2 and 4 h at 600, 700 and 800°C. The film properties, including the protection of the underlying substrate against high temperature corrosion,

  13. Thermal defect annealing of swift heavy ion irradiated ThO2

    Science.gov (United States)

    Palomares, Raul I.; Tracy, Cameron L.; Neuefeind, Joerg; Ewing, Rodney C.; Trautmann, Christina; Lang, Maik

    2017-08-01

    Isochronal annealing, neutron total scattering, and Raman spectroscopy were used to characterize the structural recovery of polycrystalline ThO2 irradiated with 2-GeV Au ions to a fluence of 1 × 1013 ions/cm2. Neutron diffraction patterns show that the Bragg signal-to-noise ratio increases and the unit cell parameter decreases as a function of isochronal annealing temperature, with the latter reaching its pre-irradiation value by 750 °C. Diffuse neutron scattering and Raman spectroscopy measurements indicate that an isochronal annealing event occurs between 275-425 °C. This feature is attributed to the annihilation of oxygen point defects and small oxygen defect clusters.

  14. Thermal annealing studies of GeTe-Sb2Te3 alloys with multiple interfaces

    Directory of Open Access Journals (Sweden)

    Valeria Bragaglia

    2017-08-01

    Full Text Available A high degree of vacancy ordering is obtained by annealing amorphous GeTe-Sb2Te3 (GST alloys deposited on a crystalline substrate, which acts as a template for the crystallization. Under annealing the material evolves from amorphous to disordered rocksalt, to ordered rocksalt with vacancies arranged into (111 oriented layers, and finally converts into the stable trigonal phase. The role of the interface in respect to the formation of an ordered crystalline phase is studied by comparing the transformation stages of crystalline GST with and without a capping layer. The capping layer offers another crystallization interface, which harms the overall crystalline quality.

  15. Instantons in Quantum Annealing: Thermally Assisted Tunneling Vs Quantum Monte Carlo Simulations

    Science.gov (United States)

    Jiang, Zhang; Smelyanskiy, Vadim N.; Boixo, Sergio; Isakov, Sergei V.; Neven, Hartmut; Mazzola, Guglielmo; Troyer, Matthias

    2015-01-01

    Recent numerical result (arXiv:1512.02206) from Google suggested that the D-Wave quantum annealer may have an asymptotic speed-up than simulated annealing, however, the asymptotic advantage disappears when it is compared to quantum Monte Carlo (a classical algorithm despite its name). We show analytically that the asymptotic scaling of quantum tunneling is exactly the same as the escape rate in quantum Monte Carlo for a class of problems. Thus, the Google result might be explained in our framework. We also found that the transition state in quantum Monte Carlo corresponds to the instanton solution in quantum tunneling problems, which is observed in numerical simulations.

  16. The influence of thermal annealing on structure and oxidation of iron nanowires

    Directory of Open Access Journals (Sweden)

    Krajewski Marcin

    2015-03-01

    Full Text Available Raman spectroscopy as well as Mössbauer spectroscopy were applied in order to study the phase composition of iron nanowires and its changes, caused by annealing in a neutral atmosphere at several temperatures ranging from 200°C to 800°C. As-prepared nanowires were manufactured via a simple chemical reduction in an external magnetic field. Both experimental techniques proved formation of the surface layer covered by crystalline iron oxides, with phase composition dependent on the annealing temperature (Ta. At higher Ta, hematite was the dominant phase in the nanowires.

  17. Integrated solutions for atmosphere production and control when annealing thermal exchanger tubes

    International Nuclear Information System (INIS)

    Chaffotte, Florent; Pinte, Gilles; Bockel-Macal, Savine; Bruchet, Pierre

    2012-01-01

    After having outlined and described the role of the atmosphere for tube annealing processes (carbon exchanges, gas phase interactions, carbon transfer at the metal-gas interface, carbon diffusion within tubes, parameters affecting oxidation), this article presents different solutions aimed at the production of atmospheres for tube annealing: nitrogen-diluted endothermic atmosphere, or nitrogen-hydrogen atmospheres. It discusses how this atmosphere must be selected. It presents different solutions for the control of these atmospheres: control of carbon potential, or control of the carbon flow. The benefits of such a control are illustrated by an example where tubes are processed in a continuous oven equipped with rollers heated by radiating tubes

  18. Fabrication of extremely thermal-stable GaN template on Mo substrate using double bonding and step annealing process

    Science.gov (United States)

    Qing, Wang; Yang, Liu; Yongjian, Sun; Yuzhen, Tong; Guoyi, Zhang

    2016-08-01

    A new layer transfer technique which comprised double bonding and a step annealing process was utilized to transfer the GaN epilayer from a sapphire substrate to a Mo substrate. Combined with the application of the thermal-stable bonding medium, the resulting two-inch-diameter GaN template showed extremely good stability under high temperature and low stress state. Moreover, no cracks and winkles were observed. The transferred GaN template was suitable for homogeneous epitaxial, thus could be used for the direct fabrication of vertical LED chips as well as power electron devices. It has been confirmed that the double bonding and step annealing technique together with the thermal-stable bonding layer could significantly improve the bonding strength and stress relief, finally enhancing the thermal stability of the transferred GaN template. Project supported by the Guangdong Innovative Research Team Program (No. 2009010044), the China Postdoctoral Science Foundation (No. 2014M562233), the National Natural Science Foundation of Guangdong, China (No. 2015A030312011), and the Opened Fund of the State Key Laboratory on Integrated Optoelectronics (No. IOSKL2014KF17).

  19. Annealing study and thermal investigation on bismuth sulfide thin films prepared by chemical bath deposition in basic medium

    Science.gov (United States)

    Dachraoui, O.; Merino, J. M.; Mami, A.; León, M.; Caballero, R.; Maghraoui-Meherzi, H.

    2018-02-01

    Bismuth sulfide thin films were prepared by chemical bath deposition using thiourea as sulfide ion source in basic medium. First, the effects of both the deposition parameters on film growth as well as the annealing effect under argon and sulfur atmosphere on as-deposited thin films were studied. The parameters were found to be influential using the Doehlert matrix experimental design methodology. Ranges for a maximum surface mass of films (3 mg cm-2) were determined. A well-crystallized major phase of bismuth sulfide with stoichiometric composition was achieved at 190 °C for 3 h. The prepared thin films were characterized using grazing incidence X-ray diffraction, scanning electron microscopy and energy-dispersive X-ray analysis. Second, the bandgap energy value was found to be 1.5 eV. Finally, the thermal properties have been studied for the first time by means of the electropyroelectric (EPE) technique. Indeed, the thermal conductivity varied in the range of 1.20-0.60 W m-1 K-1, while the thermal diffusivity values increased in terms of the annealing effect ranging from 1.8 to 3.5 10-7 m2 s-1.

  20. Rapid thermal annealed Molybdenum back contact for Cu2ZnSnS4 thin film solar cells

    Science.gov (United States)

    Liu, Xiaolei; Cui, Hongtao; Kong, Charlie; Hao, Xiaojing; Huang, Yidan; Liu, Fangyang; Song, Ning; Conibeer, Gavin; Green, Martin

    2015-03-01

    In this work, an industrially viable manufacturing process—rapid thermal annealing (RTA) of Molybdenum back contact is proposed and investigated to improve the performance of sputtered Cu2ZnSnS4 (CZTS) solar cells. The RTA process was found to facilitate Na diffusion from soda lime glass to Mo as well as CZTS and improve the crystallinity of the Mo film. Consequently, the surface morphology of the subsequently deposited CZTS absorbers is improved, which results in significant enhancement of open circuit voltage, short-circuit current density, fill factor, and conversion efficiency.

  1. Rapid thermal annealed Molybdenum back contact for Cu2ZnSnS4 thin film solar cells

    International Nuclear Information System (INIS)

    Liu, Xiaolei; Cui, Hongtao; Kong, Charlie; Hao, Xiaojing; Huang, Yidan; Liu, Fangyang; Song, Ning; Conibeer, Gavin; Green, Martin

    2015-01-01

    In this work, an industrially viable manufacturing process—rapid thermal annealing (RTA) of Molybdenum back contact is proposed and investigated to improve the performance of sputtered Cu 2 ZnSnS 4 (CZTS) solar cells. The RTA process was found to facilitate Na diffusion from soda lime glass to Mo as well as CZTS and improve the crystallinity of the Mo film. Consequently, the surface morphology of the subsequently deposited CZTS absorbers is improved, which results in significant enhancement of open circuit voltage, short-circuit current density, fill factor, and conversion efficiency

  2. 1-Dimensional simulation of thermal annealing in a commercial nuclear power plant reactor pressure vessel wall section

    Energy Technology Data Exchange (ETDEWEB)

    Nakos, J.T.; Rosinski, S.T.; Acton, R.U.

    1994-11-01

    The objective of this work was to provide experimental heat transfer boundary condition and reactor pressure vessel (RPV) section thermal response data that can be used to benchmark computer codes that simulate thermal annealing of RPVS. This specific protect was designed to provide the Electric Power Research Institute (EPRI) with experimental data that could be used to support the development of a thermal annealing model. A secondary benefit is to provide additional experimental data (e.g., thermal response of concrete reactor cavity wall) that could be of use in an annealing demonstration project. The setup comprised a heater assembly, a 1.2 in {times} 1.2 m {times} 17.1 cm thick [4 ft {times} 4 ft {times} 6.75 in] section of an RPV (A533B ferritic steel with stainless steel cladding), a mockup of the {open_quotes}mirror{close_quotes} insulation between the RPV and the concrete reactor cavity wall, and a 25.4 cm [10 in] thick concrete wall, 2.1 in {times} 2.1 in [10 ft {times} 10 ft] square. Experiments were performed at temperature heat-up/cooldown rates of 7, 14, and 28{degrees}C/hr [12.5, 25, and 50{degrees}F/hr] as measured on the heated face. A peak temperature of 454{degrees}C [850{degrees}F] was maintained on the heated face until the concrete wall temperature reached equilibrium. Results are most representative of those RPV locations where the heat transfer would be 1-dimensional. Temperature was measured at multiple locations on the heated and unheated faces of the RPV section and the concrete wall. Incident heat flux was measured on the heated face, and absorbed heat flux estimates were generated from temperature measurements and an inverse heat conduction code. Through-wall temperature differences, concrete wall temperature response, heat flux absorbed into the RPV surface and incident on the surface are presented. All of these data are useful to modelers developing codes to simulate RPV annealing.

  3. X-Ray diffraction analysis of thermally evaporated copper tin selenide thin films at different annealing temperature

    International Nuclear Information System (INIS)

    Mohd Amirul Syafiq Mohd Yunos; Zainal Abidin Talib; Wan Mahmood Mat Yunus; Josephine Liew Ying Chyi; Wilfred Sylvester Paulus

    2010-01-01

    Semiconductor thin films Copper Tin Selenide, Cu 2 SnSe 3 , a potential compound for semiconductor radiation detector or solar cell applications were prepared by thermal evaporation method onto well-cleaned glass substrates. The as-deposited films were annealed in flowing purified nitrogen, N 2 , for 2 hours in the temperature range from 100 to 500 degree Celsius. The structure of as-deposited and annealed films has been studied by X-ray diffraction technique. The semi-quantitative analysis indicated from the Reitveld refinement show that the samples composed of Cu 2 SnSe 3 and SnSe. These studies revealed that the films were structured in mixed phase between cubic space group F-43 m (no. 216) and orthorhombic space group P n m a (no. 62). The crystallite size and lattice strain were determined from Scherrer calculation method. The results show that increasing in annealing temperature resulted in direct increase in crystallite size and decrease in lattice strain. (author)

  4. Understanding the microwave annealing of silicon

    Directory of Open Access Journals (Sweden)

    Chaochao Fu

    2017-03-01

    Full Text Available Though microwave annealing appears to be very appealing due to its unique features, lacking an in-depth understanding and accurate model hinder its application in semiconductor processing. In this paper, the physics-based model and accurate calculation for the microwave annealing of silicon are presented. Both thermal effects, including ohmic conduction loss and dielectric polarization loss, and non-thermal effects are thoroughly analyzed. We designed unique experiments to verify the mechanism and extract relevant parameters. We also explicitly illustrate the dynamic interaction processes of the microwave annealing of silicon. This work provides an in-depth understanding that can expedite the application of microwave annealing in semiconductor processing and open the door to implementing microwave annealing for future research and applications.

  5. Thermal annealing of carbon nanotubes reveals a toxicological impact of the structural defects

    Science.gov (United States)

    Figarol, Agathe; Pourchez, Jérémie; Boudard, Delphine; Forest, Valérie; Berhanu, Sarah; Tulliani, Jean-Marc; Lecompte, Jean-Pierre; Cottier, Michèle; Bernache-Assollant, Didier; Grosseau, Philippe

    2015-04-01

    The biological response to pristine and annealed multi-walled carbon nanotubes (MWCNT) was assessed on murine macrophages (RAW 264.7). First, the physicochemical features of the as-produced MWCNT and annealed at 2125 °C for 1 h were fully characterized. A decrease in structural defects, hydrophobicity and catalytic impurities was detected after annealing. Thereafter, their impact on cytotoxicity, oxidative stress, and pro-inflammatory response was investigated at concentrations ranging from 15 to 120 µg mL-1. No effect of the 2125 °C treatment was detected on the cytotoxicity. In contrast, the annealed carbon nanotubes showed a significant increase of the pro-inflammatory response. We assumed that this behavior was due to the reduction in structural defects that may modify the layer of adsorbed biomolecules. Surprisingly, the purification of metallic catalysts did not have any significant impact on the oxidative stress. We suggested that the structural improvements from the 2125 °C treatment can decrease the carbon nanotube scavenging capacity and thus allow a higher free radical release which may counterbalance the decrease of oxidative stress due to a lower content of metallic impurities.

  6. Effect of thermal annealing on the structural, optical and dielectrical properties of P3HT:PC{sub 70}BM nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Aloui, Walid, E-mail: alouiwalid26@yahoo.fr [Laboratory of Condensed Matter and Nanosciences, Faculty of Sciences of Monastir, Avenue of the Environment, 5019 Monastir (Tunisia); Adhikari, Tham [Department of Chemistry, Queen’s University, Kingston, ON K7L 3N6 (Canada); Nunzi, Jean-Michel [Department of Chemistry, Queen’s University, Kingston, ON K7L 3N6 (Canada); Department of Physics, Engineering Physics and Astronomy, Queen’s University, Kingston, ON K7L 3N6 (Canada); Bouazizi, Abdelaziz [Laboratory of Condensed Matter and Nanosciences, Faculty of Sciences of Monastir, Avenue of the Environment, 5019 Monastir (Tunisia)

    2016-06-15

    Highlights: • A typical structure of ITO/PEDOT: PSS/P3HT: PC{sub 70}BM/Al was fabricated. • Charge carrier diffusion and recombination have been calculated. • AFM and optical results show that thermal annealing promotes the phase separation. • The annealing process improves the transport of charges. - Abstract: The effect of thermal annealing on the optical, structural and the dielectric properties of P3HT:PC{sub 70}BM blended films were investigated. By means of atomic force microscopy, we observed the morphology evolution of the annealed P3HT:PC{sub 70}BM nanocomposites. Raman spectroscopy showed a substantial ordering in the polymer film after annealing. The absorption spectra of the annealed P3HT:PC{sub 70}BM films were improved and red shifted than un-annealed samples. The results indicate that the P3HT in the nanocomposite becomes an ordered structure with annealing. The ordered P3HT facilitates the charge transport. From the photoluminescence measurements, the formation of polymer crystallites was observed upon annealing. Thus, the device efficiency reaches 2.2% after annealing at 150 °C. Impedance spectroscopy shows the classical complex plan curves; the low frequency is related to the effective lifetime of charge carriers and the high frequency corresponds to the diffusion time of these carriers. Global mobilities are in the range 3.8–4.6 × 10{sup −3} cm{sup 2} V{sup −1} s{sup −1}.

  7. Chemical and electrical characterisation of the segregation of Al from a CuAl alloy (90%:10% wt) with thermal anneal

    International Nuclear Information System (INIS)

    Byrne, C.; Brady, A.; Walsh, L.; McCoy, A.P.; Bogan, J.; McGlynn, E.; Rajani, K.V.; Hughes, G.

    2016-01-01

    A copper–aluminium (CuAl) alloy (90%:10% wt) has been investigated in relation to segregation of the alloying element Al, from the alloy bulk during vacuum anneal treatments. X-ray photoelectron spectroscopy (XPS) measurements were used to track the surface enrichment of Al segregating from the alloy bulk during in situ ultra-high vacuum anneals. Secondary ion mass spectroscopy (SIMS) indicates a build-up of Al at the surface of the annealed alloy relative to the bulk composition. Metal oxide semiconductor (MOS) CuAl/SiO 2 /Si structures show a shift in flatband voltage upon thermal anneal consistent with the segregation of the Al to the alloy/SiO 2 interface. Electrical four point probe measurements indicate that the segregation of Al from the alloy bulk following thermal annealing results in a decrease in film resistivity. X-ray diffraction data shows evidence for significant changes in crystal structure upon annealing, providing further evidence for expulsion of Al from the alloy bulk. - Highlights: • CuAl alloy (90%:Al 10% wt) deposited and vacuum annealed • XPS and SIMS data show segregation of Al from the alloy bulk. • Chemical changes seen indicate the reduction of Cu oxide and growth of Al Oxide. • Electrical measurements indicate a chemical change at the metal/SiO 2 interface. • All data consistent with Cu diffusion barrier layer formed

  8. Effect of an in-situ thermal annealing on the structural properties of self-assembled GaSb/GaAs quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Fernández-Delgado, N., E-mail: natalia.fernandezdelgado@alum.uca.es [Department of Material Science, Metallurgical Engineering and Inorganic Chemistry, IMEYMAT, University of Cádiz, 11510, Puerto Real, Cádiz (Spain); Herrera, M. [Department of Material Science, Metallurgical Engineering and Inorganic Chemistry, IMEYMAT, University of Cádiz, 11510, Puerto Real, Cádiz (Spain); Chisholm, M.F. [Scanning Transmission Electron Microscopy Group, Oak Ridge National Laboratory, TN (United States); Kamarudin, M.A. [Department of Physics, Lancaster University, Lancaster, LA1 4YB (United Kingdom); Department of Physics, Faculty of Science, Universiti Putra Malaysia, 43400, UPM Serdang, Selangor (Malaysia); Zhuang, Q.D.; Hayne, M. [Department of Physics, Lancaster University, Lancaster, LA1 4YB (United Kingdom); Molina, S.I. [Department of Material Science, Metallurgical Engineering and Inorganic Chemistry, IMEYMAT, University of Cádiz, 11510, Puerto Real, Cádiz (Spain)

    2017-02-15

    Highlights: • GaSb QDs are more elongated and Sb is less concentrated after the thermal annealing. • The density of misfit dislocations in GaSb QDs is reduced after the annealing. • Threading dislocations in GaSb/GaAs QDs are Sb-rich after the thermal annealing. • The gliding of a threading dislocation favors Sb diffusion in GaSb/GaAs QDs. - Abstract: In this work, the effect of the application of a thermal annealing on the structural properties of GaSb/GaAs quantum dots (QDs) is analyzed by aberration corrected high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and electron energy loss spectroscopy (EELS) Our results show that the GaSb/GaAs QDs are more elongated after the annealing, and that the interfaces are less abrupt due to the Sb diffusion. We have also found a strong reduction in the misfit dislocation density with the annealing. The analysis by EELS of a threading dislocation has shown that the dislocation core is rich in Sb. In addition, the region of the GaAs substrate delimited by the threading dislocation is shown to be Sb-rich as well. An enhanced diffusion of Sb due to a mechanism assisted by the dislocation movement is discussed.

  9. Thermal annealing behaviour of Pd Schottky contacts on melt-grown single crystal ZnO studied by IV and CV measurements

    International Nuclear Information System (INIS)

    Mtangi, W.; Auret, F.D.; Chawanda, A.; Janse van Rensburg, P.J.; Coelho, S.M.M.; Nel, J.M.; Diale, M.; Schalkwyk, L. van; Nyamhere, C.

    2012-01-01

    Highlights: ► Highly rectifying Pd/ZnO contacts have been fabricated. ► The rectification behaviour decrease with annealing temperature. ► The surface donor concentration increases with increase in annealing temperature. ► The depletion layer width at a specific reverse voltage decreases with increase in annealing temperature. - Abstract: Current–voltage (IV) and capacitance–voltage (CV) measurement techniques have successfully been employed to study the effects of annealing highly rectifying Pd/ZnO Schottky contacts. IV results reveal a decrease in the contact quality with increasing annealing temperature as confirmed by a decrease in the zero bias barrier height and an increase in the reverse current measured at −1.5 V. An average barrier height of (0.77 ± 0.02) eV has been calculated by assuming pure thermionic emission for the as-deposited material and as (0.56 ± 0.03) eV after annealing at 550 °C. The reverse current has been measured as (2.10 ± 0.01) × 10 −10 A for the as-deposited and increases by 5 orders of magnitude after annealing at 550 °C to (1.56 ± 0.01) × 10 −5 A. The depletion layer width measured at −2.0 V has shown a strong dependence on thermal annealing as it decreases from 1.09 μm after annealing at 200 °C to 0.24 μm after annealing at 500 °C, resulting in the modification of the dopant concentration within the depletion region and hence the current flowing through the interface from pure thermionic emission to thermionic field emission with the donor concentrations increasing from 6.90 × 10 15 cm −3 at 200 °C to 6.06 × 10 16 cm −3 after annealing at 550 °C. This increase in the volume concentration has been explained as an effect of a conductive channel that shifts closer to the surface after sample annealing. The series resistance has been observed to decrease with increase in annealing temperature. The Pd contacts have shown high stability up to an annealing temperature of 250 °C as revealed by the IV

  10. Thermal annealing behaviour of Pd Schottky contacts on melt-grown single crystal ZnO studied by IV and CV measurements

    Energy Technology Data Exchange (ETDEWEB)

    Mtangi, W., E-mail: wilbert.mtangi@up.ac.za [Department of Physics, University of Pretoria, Private Bag X20, Hatfield 0028 (South Africa); Auret, F.D.; Chawanda, A.; Janse van Rensburg, P.J.; Coelho, S.M.M.; Nel, J.M.; Diale, M.; Schalkwyk, L. van [Department of Physics, University of Pretoria, Private Bag X20, Hatfield 0028 (South Africa); Nyamhere, C. [Department of Physics, P.O. Box 77000, Nelson Mandela Metropolitan University, Port Elizabeth 6031 (South Africa)

    2012-02-15

    Highlights: Black-Right-Pointing-Pointer Highly rectifying Pd/ZnO contacts have been fabricated. Black-Right-Pointing-Pointer The rectification behaviour decrease with annealing temperature. Black-Right-Pointing-Pointer The surface donor concentration increases with increase in annealing temperature. Black-Right-Pointing-Pointer The depletion layer width at a specific reverse voltage decreases with increase in annealing temperature. - Abstract: Current-voltage (IV) and capacitance-voltage (CV) measurement techniques have successfully been employed to study the effects of annealing highly rectifying Pd/ZnO Schottky contacts. IV results reveal a decrease in the contact quality with increasing annealing temperature as confirmed by a decrease in the zero bias barrier height and an increase in the reverse current measured at -1.5 V. An average barrier height of (0.77 {+-} 0.02) eV has been calculated by assuming pure thermionic emission for the as-deposited material and as (0.56 {+-} 0.03) eV after annealing at 550 Degree-Sign C. The reverse current has been measured as (2.10 {+-} 0.01) Multiplication-Sign 10{sup -10} A for the as-deposited and increases by 5 orders of magnitude after annealing at 550 Degree-Sign C to (1.56 {+-} 0.01) Multiplication-Sign 10{sup -5} A. The depletion layer width measured at -2.0 V has shown a strong dependence on thermal annealing as it decreases from 1.09 {mu}m after annealing at 200 Degree-Sign C to 0.24 {mu}m after annealing at 500 Degree-Sign C, resulting in the modification of the dopant concentration within the depletion region and hence the current flowing through the interface from pure thermionic emission to thermionic field emission with the donor concentrations increasing from 6.90 Multiplication-Sign 10{sup 15} cm{sup -3} at 200 Degree-Sign C to 6.06 Multiplication-Sign 10{sup 16} cm{sup -3} after annealing at 550 Degree-Sign C. This increase in the volume concentration has been explained as an effect of a conductive channel

  11. Effect of rapid thermal annealing observed by photoluminescence measurement in GaAs1-xN x layers

    International Nuclear Information System (INIS)

    Bousbih, F.; Bouzid, S.B.; Hamdouni, A.; Chtourou, R.; Harmand, J.C.

    2005-01-01

    A set of GaAs 1-x N x samples with small nitrogen content were investigated by photoluminescence (PL) measurements as function of irradiance in order to investigate the effect of rapid thermal annealing (RTA) on photoluminescence (PL) properties. The analysis of PL spectra as function of irradiance and nitrogen content shows that the PL spectra associated to the GaAs 1- x N x layers are the result of the nitrogen localized state recombination. The results are examined as a consequence of a rapid thermal annealing (RTA). The variation of the emission band peak energy (E p ), at 10 K as a function of irradiance, is fitted by a theoretical model taking into account two types of nitrogen localized states. The variation of the PL intensity versus irradiance in the range from 1.59 to 159 W/cm 2 for different GaAs 1-x N x samples confirm that the PL spectra result from the nitrogen localized state recombination

  12. Investigating the Effect of Thermal Annealing Process on the Photovoltaic Performance of the Graphene-Silicon Solar Cell

    Directory of Open Access Journals (Sweden)

    Lifei Yang

    2015-01-01

    Full Text Available Graphene-silicon (Gr-Si Schottky solar cell has attracted much attention recently as promising candidate for low-cost photovoltaic application. For the fabrication of Gr-Si solar cell, the Gr film is usually transferred onto the Si substrate by wet transfer process. However, the impurities induced by this process at the graphene/silicon (Gr/Si interface, such as H2O and O2, degrade the photovoltaic performance of the Gr-Si solar cell. We found that the thermal annealing process can effectively improve the photovoltaic performance of the Gr-Si solar cell by removing these impurities at the Gr/Si interface. More interestingly, the photovoltaic performance of the Gr-Si solar cell can be improved, furthermore, when exposed to air environment after the thermal annealing process. Through investigating the characteristics of the Gr-Si solar cell and the properties of the Gr film (carrier density and sheet resistance, we point out that this phenomenon is caused by the natural doping effect of the Gr film.

  13. Irradiation embrittlement of reactor pressure vessel steels: Considerations for thermal annealing

    International Nuclear Information System (INIS)

    Burke, M.G.; Freyer, P.D.; Mager, T.R.

    1993-01-01

    In this paper, an overview of the irradiation embrittlement phenomenon is presented from a structure-properties viewpoint. Effects of irradiation conditions on embrittlement are first reviewed: irradiation temperature, fluence, flux, and steel or alloy composition. Then, the techniques for identifying/characterizing the irradiation-induced microstructural features are described: TEM/STEM (electron microscopy), small angle neutron scattering, atom probe field-ion microscopy, positron annihilation lifetime spectroscopy. Mechanisms of hardening and embrittlement generally consist of a ''precipitation-type'' and a ''damage-type'' component and the potential of annealing treatments for restoring the most of the original pressure vessel material toughness is examined; its conditions and mechanisms involved are discussed. Feasibility and economic evaluation of annealing costs is also carried out. 90 refs., 4 figs

  14. Thermoluminiscence and thermal annealing of F centres in KCL gamma irradiated

    International Nuclear Information System (INIS)

    Ausin Alonso, Vicente.

    1976-01-01

    The thermoluminiscence spectrum and phosphorescence decays of Harshaw KCl samples gamma irradiated at room temperature have been studied up to 400 0 C. For the six peaks found, the order of recombination kinetics, the pre-exponential factor and the activation energy have been obtained. It has been observed that the area under the thermoluminiscence curve is always proportional to the F centre concentration in the sample before heating. It was also found that there is an annealing step of F centres corresponding to each thermoluminiscence peak, when the temperature of the sample is raised at a constant rate. It is concluded that the F centres play the role of recombination centres in the annealing process, the interstitials being the mobile entities moving towards there combination centre. At some stage in the process light is emitted. (author)

  15. Thermal stability of RuO sub 2 -based bottom electrodes during various ambient annealings

    CERN Document Server

    Ahn, J H; Choi, G P; Choi, W Y; Kim, H G; Lee, W J; Yoon, S G

    1999-01-01

    RuO sub 2 thin films were prepared on SiO sub 2 /Si, TiN/SiO sub 2 /Si and Ru/poly-Si by using DC magnetron sputtering. The annealing of the RuO sub 2 -based bottom electrodes was performed in oxygen and argon ambients and in high vacuum in the temperature range of 400 .deg. C approx 800 .deg. C. In oxygen-ambient annealing, the surface morphology was drastically changed due to the evaporation of ruthenium dioxides in the form of RuO sub 3 and RuO sub 4. The RuO sub 2 thin film annealed in high vacuum was reduced to the Ru metal phase. Evaporation and reduction of the RuO sub 2 thin films could actually be observed during the deposition of (Ba,Sr)TiO sub 3 thin films. oxygen diffusion through the RuO sub 2 /diffusion barrier/poly-Si structures is also discussed

  16. Study of defects created in silicon during thermal annealings - Correlation with the presence of oxygen

    International Nuclear Information System (INIS)

    Olivier, Michel

    1975-01-01

    Defects generation and precipitation phenomena in Czochralski silicon crystals annealed ten of hours at 1000 C have been observed. The defects (perfect dislocation loops emitted by semi-coherent precipitates, Frank loops in correlation with coherent precipitates) are studied by Transmission Electron Microscopy, X-Ray Topography and chemical etching. The generation of defects is connected to the precipitation of interstitial oxygen as it is shown by studying the infrared absorption at 9 μm. We present a lot of experimental results which indicates that the precipitates are SiO 2 clusters; in particular, we show that this hypothesis can explain the presence, after annealing, of an infrared absorption band at 8,2 μm. Some results on Czochralski silicon crystals annealed at 1150 deg. C and 1250 deg. C are then presented. In particular, X-Ray Topography studies show the presence of large (∼100 μm) Frank loops which seem connected to oxygen precipitation. (author) [fr

  17. Effect of Thermal Annealing on Carbon in In-situ Phosphorous-Doped Si{sub 1-x}C{sub x} films

    Energy Technology Data Exchange (ETDEWEB)

    Adam, Thomas, E-mail: tadam@us.ibm.com [IBM Research at Albany Nanotech, 257 Fuller Road, Albany, NY 12203 (United States); Loubet, Nicolas [STMicroelectronics at Albany Nanotech, 257 Fuller Road, Albany, NY 12203 (United States); Reznicek, Alexander; Paruchuri, Vamsi [IBM Research at Albany Nanotech, 257 Fuller Road, Albany, NY 12203 (United States); Sampson, Ron [STMicroelectronics at Albany Nanotech, 257 Fuller Road, Albany, NY 12203 (United States); Sadana, Devendra [IBM Research, 1101 Kitchawan Road, Yorktown, NY 10598 (United States)

    2012-02-01

    The effect of thermal heat treatment on carbon in in-situ phosphorous-doped silicon-carbon is studied as a function of annealing temperature and type. Films of 0 to 2% carbon were deposited using cyclic chemical vapor deposition at reduced pressures. Secondary ion-mass spectroscopy and high-resolution X-ray diffraction were employed to extract the total and substitutional carbon concentration in samples with phosphorous levels of mid-10{sup 20} cm{sup -3}. It was found that millisecond laser annealing drastically improves substitutionality while high thermal budget treatments (furnace, rapid-thermal, or spike annealing) resulted in an almost complete loss of substitutional carbon, independent of preceding or subsequent laser heat treatments.

  18. Effects of thickness and annealing condition on magnetic properties and thermal stabilities of Ta/Nd/NdFeB/Nd/Ta sandwiched films

    International Nuclear Information System (INIS)

    Liu Wen-Feng; Zhang Min-Gang; Zhang Ke-Wei; Zhang Hai-Jie; Chai Yue-Sheng; Xu Xiao-Hong

    2016-01-01

    Ta/Nd/NdFeB/Nd/Ta sandwiched films are deposited by magnetron sputtering on Si (100) substrates, and subsequently annealed in vacuum at different temperatures for different time. It is found that both the thickness of NdFeB and Nd layer and the annealing condition can affect the magnetic properties of Ta/Nd/NdFeB/Nd/Ta films. Interestingly, the thickness and annealing temperature show the relevant behaviors that can affect the magnetic properties of the film. The high coercivity of 24.1 kOe (1 Oe = 79.5775 A/m) and remanence ratio (remanent magnetization/saturation magnetization) of 0.94 can be obtained in a Ta/Nd(250 nm)/NdFeB(600 nm)/Nd(250 nm)/Ta film annealed for 3 min at 1023 K. In addition, the thermal stability of the film is also linked to the thickness of NdFeB and Nd layer and the annealing temperature as well. The excellent thermal stability can be achieved in a Ta/Nd(250 nm)/NdFeB(600 nm)/Nd(250 nm)/Ta film annealed at 1023 K. (paper)

  19. Continuous anneal method for characterizing the thermal stability of ultraviolet Bragg gratings

    DEFF Research Database (Denmark)

    Rathje, Jacob; Kristensen, Martin; Pedersen, Jens Engholm

    2000-01-01

    We present a new method for determining the long-term stability of UV-induced fiber Bragg gratings. We use a continuous temperature ramp method in which systematic variation of the ramp speed probes both the short- and long-term stability. Results are obtained both for gratings written in D2 loaded...... we resolve two separate energy distributions, suggesting that two different defects are involved. The experiments show that complicated decays originating from various energy distributions can be analyzed with this continuous isochronal anneal method. The results have both practical applications...

  20. Microstructural and Fractographic Characterization of a Thermally Embrittled Nuclear Grade Steel: Part I - Annealing

    Directory of Open Access Journals (Sweden)

    Tarpani José R.

    2002-01-01

    Full Text Available A nuclear reactor pressure vessel steel was submitted to different annealing heat treatments aimed at simulating neutron irradiation damage. The obtained microstructures were mechanically tested with subsequent metallographic and fractographic characterization. The relevant microstructural and fractographic aspects were employed in the interpretation of the mechanical behavior of the microstructures in both quasi-static (J-R curve and dynamic (Charpy impact loading regimes. A well defined relationship was determined between the elastic-plastic fracture toughness parameter J-integral and the Charpy impact energy for very most of the microstructures.

  1. Transparent thin-film transistor exploratory development via sequential layer deposition and thermal annealing

    International Nuclear Information System (INIS)

    Hong, David; Chiang, Hai Q.; Presley, Rick E.; Dehuff, Nicole L.; Bender, Jeffrey P.; Park, Cheol-Hee; Wager, John F.; Keszler, Douglas A.

    2006-01-01

    A novel deposition methodology is employed for exploratory development of a class of high-performance transparent thin-film transistor (TTFT) channel materials involving oxides composed of heavy-metal cations with (n - 1)d 10 ns 0 (n ≥ 4) electronic configurations. The method involves sequential radio-frequency sputter deposition of thin, single cation oxide layers and subsequent post-deposition annealing in order to obtain a multi-component oxide thin film. The viability of this rapid materials development methodology is demonstrated through the realization of high-performance TTFTs with channel layers composed of zinc oxide/tin oxide, and tin oxide/indium oxide

  2. Thermal effect on structural and magnetic properties of Fe78B13Si9 annealed amorphous ribbons

    Directory of Open Access Journals (Sweden)

    Soltani Mohamed Larbi

    2017-01-01

    Full Text Available In the present work, we study the influence of thermal treatments on the magnetic properties of as-quenched and pre-crystallized Fe78Si9B13 after stress relaxation. The crystallization behavior of amorphous and treated Fe78Si9B13 ribbons was revisited. The measurements were carried out by means of Differential Scanning Calorimetry, by X-ray diffraction and by Vibrating Sample Magnetometer, Susceptometer and fluxmeter. Relaxed samples were heated in the resistivity device up to 700°C and annealed near the onset temperature about 420°C for respectively 1, 3, 5, 8 hours. In as-quenched samples, two transition points occur at about 505°C and 564°C but in relaxed sample, the transition points have been found about 552°C and 568°C. Kinetics of crystallization was deduced for all studied samples. Annealing of the as-purchased ribbon shows the occurrence of α-Fe and tetragonal Fe3B resulting from the crystallization of the remaining amorphous phase. The effects on magnetic properties were pointed out by relating the structural evolution of the samples. The magnetic measurements show that annealing change the saturation magnetization and the coercive magnetic field values, hence destroying the good magnetic properties of the material. The heat treatment shows that the crystallization has greatly altered the shape of the cycles and moved the magnetic saturation point of the samples. The effect of treatment on the magneto-crystalline anisotropy is also demonstrated.

  3. Effect of thermal annealing in vacuum on the photovoltaic properties of electrodeposited Cu2O-absorber solar cell

    Directory of Open Access Journals (Sweden)

    Dimopoulos T.

    2014-07-01

    Full Text Available Heterojunction solar cells were fabricated by electrochemical deposition of p-type, cuprous oxide (Cu2O absorber on sputtered, n-type ZnO layer. X-ray diffraction measurements revealed that the as-deposited absorber consists mainly of Cu2O, but appreciable amounts of metallic Cu and cupric oxide (CuO are also present. These undesired oxidation states are incorporated during the deposition process and have a detrimental effect on the photovoltaic properties of the cells. The open circuit voltage (VOC, short circuit current density (jSC, fill factor (FF and power conversion efficiency (η of the as-deposited cells are 0.37 V, 3.71 mA/cm2, 35.7% and 0.49%, respectively, under AM1.5G illumination. We show that by thermal annealing in vacuum, at temperatures up to 300 °C, compositional purity of the Cu2O absorber could be obtained. A general improvement of the heterojunction and bulk materials quality is observed, reflected upon the smallest influence of the shunt and series resistance on the transport properties of the cells in dark and under illumination. Independent of the annealing temperature, transport is dominated by the space-charge layer generation-recombination current. After annealing at 300 °C the solar cell parameters could be significantly improved to the values of: VOC = 0.505 V, jSC = 4.67 mA/cm2, FF = 47.1% and η = 1.12%.

  4. Thermal effect on structural and magnetic properties of Fe78B13Si9 annealed amorphous ribbons

    Science.gov (United States)

    Soltani, Mohamed Larbi; Touares, Abdelhay; Aboki, Tiburce A. M.; Gasser, Jean-Georges

    2017-08-01

    In the present work, we study the influence of thermal treatments on the magnetic properties of as-quenched and pre-crystallized Fe78Si9B13 after stress relaxation. The crystallization behavior of amorphous and treated Fe78Si9B13 ribbons was revisited. The measurements were carried out by means of Differential Scanning Calorimetry, by X-ray diffraction and by Vibrating Sample Magnetometer, Susceptometer and fluxmeter. Relaxed samples were heated in the resistivity device up to 700°C and annealed near the onset temperature about 420°C for respectively 1, 3, 5, 8 hours. In as-quenched samples, two transition points occur at about 505°C and 564°C but in relaxed sample, the transition points have been found about 552°C and 568°C. Kinetics of crystallization was deduced for all studied samples. Annealing of the as-purchased ribbon shows the occurrence of α-Fe and tetragonal Fe3B resulting from the crystallization of the remaining amorphous phase. The effects on magnetic properties were pointed out by relating the structural evolution of the samples. The magnetic measurements show that annealing change the saturation magnetization and the coercive magnetic field values, hence destroying the good magnetic properties of the material. The heat treatment shows that the crystallization has greatly altered the shape of the cycles and moved the magnetic saturation point of the samples. The effect of treatment on the magneto-crystalline anisotropy is also demonstrated.

  5. 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.

  6. A thermal lens model including the Soret effect

    International Nuclear Information System (INIS)

    Cabrera, Humberto; Sira, Eloy; Rahn, Kareem; Garcia-Sucre, Maximo

    2009-01-01

    In this letter we generalize the thermal lens model to account for the Soret effect in binary liquid mixtures. This formalism permits the precise determination of the Soret coefficient in a steady-state situation. The theory is experimentally verified using the measured values in the ethanol/water mixtures. The time evolution of the Soret signal has been used to derive mass-diffusion times from which mass-diffusion coefficients were calculated. (Author)

  7. Enhanced Photoelectrochemical Behavior of H-TiO2 Nanorods Hydrogenated by Controlled and Local Rapid Thermal Annealing

    Science.gov (United States)

    Wang, Xiaodan; Estradé, Sonia; Lin, Yuanjing; Yu, Feng; Lopez-Conesa, Lluis; Zhou, Hao; Gurram, Sanjeev Kumar; Peiró, Francesca; Fan, Zhiyong; Shen, Hao; Schaefer, Lothar; Braeuer, Guenter; Waag, Andreas

    2017-05-01

    Recently, colored H-doped TiO2 (H-TiO2) has demonstrated enhanced photoelectrochemical (PEC) performance due to its unique crystalline core—disordered shell nanostructures and consequent enhanced conduction behaviors between the core-shell homo-interfaces. Although various hydrogenation approaches to obtain H-TiO2 have been developed, such as high temperature hydrogen furnace tube annealing, high pressure hydrogen annealing, hydrogen-plasma assisted reaction, aluminum reduction and electrochemical reduction etc., there is still a lack of a hydrogenation approach in a controlled manner where all processing parameters (temperature, time and hydrogen flux) were precisely controlled in order to improve the PEC performance of H-TiO2 and understand the physical insight of enhanced PEC performance. Here, we report for the first time a controlled and local rapid thermal annealing (RTA) approach to prepare hydrogenated core-shell H-TiO2 nanorods grown on F:SnO2 (FTO) substrate in order to address the degradation issue of FTO in the typical TiO2 nanorods/FTO system observed in the conventional non-RTA treated approaches. Without the FTO degradation in the RTA approach, we systematically studied the intrinsic relationship between the annealing temperature, structural, optical, and photoelectrochemical properties in order to understand the role of the disordered shell on the improved photoelectrochemical behavior of H-TiO2 nanorods. Our investigation shows that the improvement of PEC performance could be attributed to (i) band gap narrowing from 3.0 to 2.9 eV; (ii) improved optical absorption in the visible range induced by the three-dimensional (3D) morphology and rough surface of the disordered shell; (iii) increased proper donor density; (iv) enhanced electron-hole separation and injection efficiency due to the formation of disordered shell after hydrogenation. The RTA approach developed here can be used as a suitable hydrogenation process for TiO2 nanorods/FTO system for

  8. Thermal-annealing effects on the structural and magnetic properties of 10% Fe-doped SnO{sub 2} nanoparticles synthetized by a polymer precursor method

    Energy Technology Data Exchange (ETDEWEB)

    Aragón, F.H., E-mail: fermin964@hotmail.com [Núcleo de Física Aplicada, Instituto de Física, Universidade de Brasília, Brasília DF 70910-900 (Brazil); Instituto de Ciências Biológicas, Pós-graduação em Nanociência e Nanobiotecnologia, Universidade de Brasília, Brasilia DF 70919-970 (Brazil); Coaquira, J.A.H. [Núcleo de Física Aplicada, Instituto de Física, Universidade de Brasília, Brasília DF 70910-900 (Brazil); Nagamine, L.C.C.M.; Cohen, R. [Instituto de Física, Universidade de São Paulo, São Paulo SP 05508-090 (Brazil); Silva, S.W. da [Núcleo de Física Aplicada, Instituto de Física, Universidade de Brasília, Brasília DF 70910-900 (Brazil); Instituto de Ciências Biológicas, Pós-graduação em Nanociência e Nanobiotecnologia, Universidade de Brasília, Brasilia DF 70919-970 (Brazil); and others

    2015-02-01

    In this work, we present the experimental results of Sn{sub 0.9}Fe{sub 0.1}O{sub 2} nanoparticles synthesized by a polymer precursor method. Studies were performed in the as-prepared (AP) and thermally-annealed (TA) samples. The X-ray diffraction (XRD) data analysis carried out using the Rietveld refinement method shows the formation of only the rutile-type structure in the AP sample and this phase remains stable for the TA sample. Additionally, the mean crystallite size shows an increase from ∼4 nm to ∼17 nm after the annealing and a clear reduction of the residual strain has also been determined. Micro-Raman spectroscopy measurements show the formation of an iron oxide phase (likely α-Fe{sub 2}O{sub 3}) after the thermal treatment. Magnetic measurements show a paramagnetic behavior for the AP sample and the coexistence of a weak ferromagnetism and paramagnetism for the TA sample. The magnetically-ordered contribution of the TA sample has been assigned to the formation of the hematite phase. DC and AC magnetic features of the TA sample are consistent with a cluster-glass behavior which seems to be related to the magnetic disorder of spins located at the particle surface. Those spins clusters seem to be formed due to the diffusion of iron ions from the core of the particle to the surface caused by the annealing process. - Highlights: • Thermal annealing effects in the 10% Fe-doped SnO{sub 2} nanoparticles have been studied. • XRD data analysis shows the formation of the rutile-type structure. • Raman measurements show the formation of small amount of α-Fe{sub 2}O{sub 3} after the annealing. • Paramagnetic and magnetically ordered phases were determined after the annealing. • Spin clusters likely at the particle surface have been formed after the annealing.

  9. Effect of thermal annealing on the microstructures and photocatalytic performance of silver orthophosphate: The synergistic mechanism of Ag vacancies and metallic Ag

    International Nuclear Information System (INIS)

    Yan, Tingjiang; Guan, Wenfei; Xiao, Ying; Tian, Jun; Qiao, Zheng; Zhai, Huishan; Li, Wenjuan; You, Jinmao

    2017-01-01

    Highlights: • Ag 3 PO 4 was initially prepared via ion-exchange reaction and then annealed in air. • Thermal annealing also resulted in the formation of metallic Ag and Ag vacancies. • The annealed samples exhibited superior activity to the pristine sample. • Both Ag vacancies and metallic Ag contributed to the high activity. - Abstract: In this work, a simple thermal annealing route has been developed to improve the photocatalytic performance of silver orthophosphate (Ag 3 PO 4 ) photocatalyst toward organic pollutants degradation under visible light irradiation. The experimental results indicated that thermal treatment of Ag 3 PO 4 led to an obvious lattice shift towards right and significantly narrowed band gap energies due to the formation of Ag vacancies and metallic Ag during Ag 3 PO 4 decomposition. These structural variations notably affected the photocatalytic performance of Ag 3 PO 4 photocatalysts. The activity of the annealed samples was found to be significantly enhanced toward the degradation of MO dye. The highest activity was observed over the sample annealed at 400 °C, which exceeded that of pristine Ag 3 PO 4 by a factor of about 21 times. By means of photoluminescence spectroscopy and photoelectrochemical measurements, we propose that the enormous enhancement in activity was mainly attributed to the efficient separation of photogenerated electrons and holes driven by the synergistic effect of Ag vacancies and metallic Ag. The strong interaction between annealed particles also inhibited the dissolution of Ag + from Ag 3 PO 4 into aqueous solution, contributing to an improved photocatalytic stability. The strategy presented here provides an ideal platform for the design of other highly efficient and stable Ag-based photocatalysts for broad applications in the field of photocatalysis.

  10. Evolution of free volume in ultrasoft magnetic FeZrN films during thermal annealing

    NARCIS (Netherlands)

    Chechenin, NG; van Veen, A; Schut, H; Chezan, AR; Boerma, DO; Vystavel, T; De Hosson, JTM; DeHaven, PW; Field, DP; Harkness, SD; Sutliff, JA; Szpunar, JA; Tang, L; Thomson, T; Vaudin, MD

    2002-01-01

    The thermal stability of nanocrystalline ultra-soft magnetic (Fe98Zr2)(1-x)N-x films with x=0.10-0.25 was studied using high-resolution transmission electron microscopy (HRTEM), positron beam analysis (PBA) and thermal desorption spectrometry (TDS). The results demonstrate that grain growth during

  11. Redshift and blueshift of GaNAs/GaAs multiple quantum wells induced by rapid thermal annealing

    Science.gov (United States)

    Sun, Yijun; Cheng, Zhiyuan; Zhou, Qiang; Sun, Ying; Sun, Jiabao; Liu, Yanhua; Wang, Meifang; Cao, Zhen; Ye, Zhi; Xu, Mingsheng; Ding, Yong; Chen, Peng; Heuken, Michael; Egawa, Takashi

    2018-02-01

    The effects of rapid thermal annealing (RTA) on the optical properties of GaNAs/GaAs multiple quantum wells (MQWs) grown by chemical beam epitaxy (CBE) are studied by photoluminescence (PL) at 77 K. The results show that the optical quality of the MQWs improves significantly after RTA. With increasing RTA temperature, PL peak energy of the MQWs redshifts below 1023 K, while it blueshifts above 1023 K. Two competitive processes which occur simultaneously during RTA result in redshift at low temperature and blueshift at high temperature. It is also found that PL peak energy shift can be explained neither by nitrogen diffusion out of quantum wells nor by nitrogen reorganization inside quantum wells. PL peak energy shift can be quantitatively explained by a modified recombination coupling model in which redshift nonradiative recombination and blueshift nonradiative recombination coexist. The results obtained have significant implication on the growth and RTA of GaNAs material for high performance optoelectronic device application.

  12. Investigation of Near-Surface Defects Induced by Spike Rapid Thermal Annealing in c-SILICON Solar Cells

    Science.gov (United States)

    Liu, Guodong; Ren, Pan; Zhang, Dayong; Wang, Weiping; Li, Jianfeng

    2016-01-01

    The defects induced by a spike rapid thermal annealing (RTA) process in crystalline silicon (c-Si) solar cells were investigated by the photoluminescence (PL) technique and the transmission electron microscopy (TEM), respectively. Dislocation defects were found to form in the near-surface junction region of the monocrystalline Si solar cell after a spike RTA process was performed at 1100∘C. Photo J-V characteristics were measured on the Si solar cell before and after the spike RTA treatments to reveal the effects of defects on the Si cell performances. In addition, the Silvaco device simulation program was used to study the effects of defects density on the cell performances by fitting the experimental data of RTA-treated cells. The results demonstrate that there was an obvious degradation in the Si solar cell performances when the defect density after the spike RTA treatment was above 1×1013cm-3.

  13. Structural Reorganization of CNC in Injection-Molded CNC/PBAT Materials under Thermal Annealing.

    Science.gov (United States)

    Mariano, Marcos; El Kissi, Nadia; Dufresne, Alain

    2016-10-04

    Composite materials were prepared by extrusion and injection molding from polybutyrate adipate terephthalate (PBAT) and high aspect ratio cellulose nanocrystals (CNCs) extracted from capim dourado fibers. Three CNC contents were used, corresponding to 0.5, 1, and 2 times the theoretical percolation threshold. Small-amplitude oscillary shear (SAOS) experiments show that as the CNC content increases, a more elastic behavior is observed but no percolating network can form within the polymeric matrix as a result of the high shear rates involved during the injection-molding process. Annealing of the samples at 170 °C was performed, and the possible reorganization of the nanofiller was investigated. This reorganization was further elucidated using 2D-SAOS and creep experiments.

  14. In-redistribution in a GaInN quantum well upon thermal annealing

    International Nuclear Information System (INIS)

    Hahn, E.; Rosenauer, A.; Gerthsen, D.; Off, J.; Perez-Solorzano, V.; Jetter, M.; Scholz, F.

    2002-01-01

    A GaInN quantum-well structure with an average In-concentration of 16%, grown by metal organic chemical vapor deposition (MOCVD) on a SiC substrate, was studied by transmission electron microscopy (TEM) and photoluminescence spectroscopy (PL) before and after an one-hour annealing treatment at 980 C. Due to the heat treatment, the formation of In-rich clusters with extensions between 10 nm and 100 nm and In-concentrations above 80% was observed. Nevertheless, the PL exhibits a blue shift in the PL-peak energy of about 90 meV compared to the as-grown sample and do not show a significant influence of the In-rich clusters on the emission wavelength. (Abstract Copyright [2002], Wiley Periodicals, Inc.)

  15. SU-E-T-112: Experimental Characterization of a Novel Thermal Reservoir for Consistent and Accurate Annealing of High-Sensitivity TLDs.

    Science.gov (United States)

    Donahue, W; Bongiorni, P; Hearn, R; Rodgers, J; Nath, R; Chen, Z

    2012-06-01

    To develop and characterize a novel thermal reservoir for consistent and accurate annealing of high-sensitivity thermoluminescence dosimeters (TLD-100H) for dosimetry of brachytherapy sources. The sensitivity of TLD-100H is about 18 times that of TLD-100 which has clear advantages in for interstitial brachytherapy sources. However, the TLD-100H requires a short high temperature annealing cycle (15 min.) and opening and closing the oven door causes significant temperature fluctuations leading to unreliable measurements. A new thermal reservoir made of aluminum alloy was developed to provide stable temperature environment in a standard hot air oven. The thermal reservoir consisted of a 20 cm × 20 cm × 8 cm Al block with a machine-milled chamber in the middle to house the aluminum TLD holding tray. The thermal reservoir was placed inside the oven until it reaches thermal equilibrium with oven chamber. The temperatures of the oven chamber, heat reservoir, and TLD holding tray were monitored by two independent thermo-couples which interfaced digitally to a control computer. A LabView interface was written for monitoring and recording the temperatures in TLD holding tray, the thermal reservoir, and oven chamber. The temperature profiles were measured as a function of oven-door open duration. The settings for oven chamber temperature and oven door open-close duration were optimized to achieve a stable temperature of 240 0C in the TLD holding tray. Complete temperature profiles of the TLD annealing tray over the entire annealing process were obtained. A LabView interface was written for monitoring and recording the temperatures in TLD holding The use of the thermal reservoir has significantly reduced the temperature fluctuations caused by the opening of oven door when inserting the TLD holding tray into the oven chamber. It has enabled consistent annealing of high-sensitivity TLDs. A comprehensive characterization of a custom-built novel thermal reservoir for annealing

  16. Activation of ion implanted Si for backside processing by Ultra-fast Laser Thermal Annealing: Energy homogeneity and micro-scale sheet resistance

    DEFF Research Database (Denmark)

    Huet, K.; Lin, Rong; Boniface, C

    2009-01-01

    In this paper ion activation of implanted silicon using ultra-fast laser thermal annealing (LTA) process was discussed. The results stated that there was high dopant activation using LTA process for over 70%, excellent within shot activation uniformity, and there was a possibility for overlap...

  17. Electrical and structural properties of (Pd/Au) Schottky contact to as grown and rapid thermally annealed GaN grown by MBE

    Energy Technology Data Exchange (ETDEWEB)

    Nirwal, Varun Singh, E-mail: varun.nirwal30@gmail.com; Singh, Joginder; Gautam, Khyati; Peta, Koteswara Rao [Department of Electronic Science, University of Delhi South Campus, Benito Juarez Road, New Delhi-110021 (India)

    2016-05-06

    We studied effect of thermally annealed GaN surface on the electrical and structural properties of (Pd/Au) Schottky contact to Ga-polar GaN grown by molecular beam epitaxy on Si substrate. Current voltage (I-V) measurement was used to study electrical properties while X-ray diffraction (XRD) measurement was used to study structural properties. The Schottky barrier height calculated using I-V characteristics was 0.59 eV for (Pd/Au) Schottky contact on as grown GaN, which increased to 0.73 eV for the Schottky contact fabricated on 700 °C annealed GaN film. The reverse bias leakage current at -1 V was also significantly reduced from 6.42×10{sup −5} A to 7.31×10{sup −7} A after annealing. The value of series resistance (Rs) was extracted from Cheung method and the value of R{sub s} decreased from 373 Ω to 172 Ω after annealing. XRD results revealed the formation of gallide phases at the interface of (Pd/Au) and GaN for annealed sample, which could be the reason for improvement in the electrical properties of Schottky contact after annealing.

  18. Thermal Annealing Effect on Structural, Morphological, and Sensor Performance of PANI-Ag-Fe Based Electrochemical E. coli Sensor for Environmental Monitoring.

    Science.gov (United States)

    Mohammad Naim, Norshafadzila; Abdullah, H; Umar, Akrajas Ali; Abdul Hamid, Aidil; Shaari, Sahbudin

    2015-01-01

    PANI-Ag-Fe nanocomposite thin films based electrochemical E. coli sensor was developed with thermal annealing. PANI-Ag-Fe nanocomposite thin films were prepared by oxidative polymerization of aniline and the reduction process of Ag-Fe bimetallic compound with the presence of nitric acid and PVA. The films were deposited on glass substrate using spin-coating technique before they were annealed at 300 °C. The films were characterized using XRD, UV-Vis spectroscopy, and FESEM to study the structural and morphological properties. The electrochemical sensor performance was conducted using I-V measurement electrochemical impedance spectroscopy (EIS). The sensitivity upon the presence of E. coli was measured in clean water and E. coli solution. From XRD analysis, the crystallite sizes were found to become larger for the samples after annealing. UV-Vis absorption bands for samples before and after annealing show maximum absorbance peaks at around 422 nm-424 nm and 426 nm-464 nm, respectively. FESEM images show the diameter size for nanospherical Ag-Fe alloy particles increases after annealing. The sensor performance of PANI-Ag-Fe nanocomposite thin films upon E. coli cells in liquid medium indicates the sensitivity increases after annealing.

  19. Thermal Annealing Effect on Structural, Morphological, and Sensor Performance of PANI-Ag-Fe Based Electrochemical E. coli Sensor for Environmental Monitoring

    Directory of Open Access Journals (Sweden)

    Norshafadzila Mohammad Naim

    2015-01-01

    Full Text Available PANI-Ag-Fe nanocomposite thin films based electrochemical E. coli sensor was developed with thermal annealing. PANI-Ag-Fe nanocomposite thin films were prepared by oxidative polymerization of aniline and the reduction process of Ag-Fe bimetallic compound with the presence of nitric acid and PVA. The films were deposited on glass substrate using spin-coating technique before they were annealed at 300°C. The films were characterized using XRD, UV-Vis spectroscopy, and FESEM to study the structural and morphological properties. The electrochemical sensor performance was conducted using I-V measurement electrochemical impedance spectroscopy (EIS. The sensitivity upon the presence of E. coli was measured in clean water and E. coli solution. From XRD analysis, the crystallite sizes were found to become larger for the samples after annealing. UV-Vis absorption bands for samples before and after annealing show maximum absorbance peaks at around 422 nm–424 nm and 426 nm–464 nm, respectively. FESEM images show the diameter size for nanospherical Ag-Fe alloy particles increases after annealing. The sensor performance of PANI-Ag-Fe nanocomposite thin films upon E. coli cells in liquid medium indicates the sensitivity increases after annealing.

  20. Rapid thermal annealing effects on the microstructure and the thermoelectric properties of electrodeposited Bi{sub 2}Te{sub 3} film

    Energy Technology Data Exchange (ETDEWEB)

    Rashid, Mohammad Mamunur [School of Electrical Engineering, University of Ulsan, 93 Daehak-ro, Nam-gu, Ulsan 680-749 (Korea, Republic of); Cho, Kyung Ho [Agency for Defense Development, Yuseong P.O. Box 35-42, Daejeon 305-600 (Korea, Republic of); Chung, Gwiy-Sang, E-mail: gschung@ulsan.ac.kr [School of Electrical Engineering, University of Ulsan, 93 Daehak-ro, Nam-gu, Ulsan 680-749 (Korea, Republic of)

    2013-08-15

    Bismuth telluride thermoelectric films were prepared by galvanostatic process from 1 M nitric acid solution containing 8 mM Bi{sup 3+} and 8 mM HTeO{sub 2}{sup +}. Both the n and p-type films were deposited. The thermoelectric properties of the films were measured before and after the rapid thermal annealing treatment to observe the annealing effects on the as-deposited film. Post annealing treatment was carried out under Ar environment at 200–300 °C for 2–10 min duration. Annealing effects on microstructure were examined from X-Ray diffraction (XRD) patterns and Scanning Electron Microscopy images. Electrical transport properties were analyzed by Hall Effect measurement system. The analysis revealed that the carrier density decreased and the carrier mobility increased with the enhancing of annealing temperature and duration. The Seebeck coefficient and power factor were improved significantly after rapid annealing treatment for both n and p-type Bi{sub 2}Te{sub 3} films. For n-type Bi{sub 2}Te{sub 3} film, the Seebeck coefficient improved about three-fold (from −57 to −169.49 μV/K) and the power factor improved around six-fold (from 2.74 to 17.37 μW/K{sup 2} cm) after annealing. On the other hand, for p-type Bi{sub 2}Te{sub 3} film the Seebeck coefficient enhanced around three-fold (from 28 to 112.3 μV/K) and the power factor enhanced around two-fold (from 2.57 to 4.43 μW/K{sup 2} cm) after annealing.

  1. Structural and mechanical study of thermally annealed tungsten nitride thin films

    Directory of Open Access Journals (Sweden)

    P.L. Moharana

    2016-09-01

    Full Text Available Tungsten nitride films were deposited by RF reactive magnetron sputtering using Tungsten target. The films were subsequently annealed under high vacuum at different temperatures (700–850 °C for 2 h each. The phase of the films were obtained using X-ray diffraction. EDAX and Nano-indentation tests were carried out to obtain the elemental composition and hardness respectively. XRD results of the as prepared film show the formation of pure fcc W2N phase and it is stable up to 700 °C. Beyond 700 °C mixed phase of W and W2N were observed. Mechanical study shows almost stable hardness value up to 700 °C temperature and beyond that temperature, hardness value reduce drastically, due to transformation of W2N phase to pure W phase. Our preliminary study shows that these films were stable up to <800 °C.

  2. The change of electric field and of some other insulating properties during isochronal annealing in thermally poled Ge-doped silica films

    DEFF Research Database (Denmark)

    Liu, Q.M.; Poumellec, B.; Braga, D.

    2005-01-01

    The secondary electron emission contrast between poled and unpoled regions in thermally poled Ge-doped silica films were measured according to different annealing temperatures and electron doses with electron acceleration energy of 5 keV. It is used for measuring the change on annealing of poling...... induced electric field and other insulating properties like electron traps population and conductivity in high field. Concerning the change of the contrast at low dose arising from the poling electric field, we show that this field begins to disappear at around 450 degrees C and is erased completely...

  3. Si diffusion in compositional disordering of Si-implanted GaAs/AlGaAs superlattices induced by rapid thermal annealing

    International Nuclear Information System (INIS)

    Uematsu, Masashi; Yanagawa, Fumihiko

    1988-01-01

    The Si diffusion in Si-implanted GaAs/Al 0.5 Ga 0.5 As superlattices intermixed in the disrodering process induced by rapid thermal annealing (RTA), is investigated by means of secondary ion mass spectroscopy (SIMS). The SIMS profiles indicate that no fast Si diffusion occurs during the disordering, and the disordering occurs when the Si concentration exceeds 1 x 10 19 cm -3 , which is about three times larger than the threshold value for the disordering by furnace annealing (FA). The number of Si atoms which are allowed to pass through the heterointerface is considered to be essential for disordering. (author)

  4. Effects of thermal annealing on deep-level defects and minority-carrier electron diffusion length in Be-doped InGaAsN

    International Nuclear Information System (INIS)

    Xie, S.Y.; Yoon, S.F.; Wang, S.Z.

    2005-01-01

    We report the effects of ex situ thermal annealing on the deep-level defects and the minority-carrier electron diffusion length in Be-doped, p-type In 0.03 Ga 0.97 As 0.99 N 0.01 grown by solid source molecular-beam epitaxy. Deep-level transient spectroscopy measurements reveal two majority-carrier hole traps, HT1 (0.18 eV) and HT4 (0.59 eV), and two minority-carrier electron traps, ET1 (0.09 eV) and ET3 (0.41 eV), in the as-grown sample. For the sample with postgrowth thermal annealing, the overall deep-level defect-concentration is decreased. Two hole traps, HT2 (0.39 eV) and HT3 (0.41 eV), and one electron trap, ET2 (0.19 eV), are observed. We found that the minority-carrier electron diffusion length increases by ∼30% and the leakage current of the InGaAsN/GaAs p-n junction decreases by 2-3 orders after thermal annealing. An increase of the net acceptor concentration after annealing is also observed and can be explained by a recently proposed three-center-complex model

  5. Synthesis of stoichiometric Ca{sub 2}Fe{sub 2}O{sub 5} nanoparticles by high-energy ball milling and thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Amorim, B.F.; Morales, M.A.; Bohn, F.; Carriço, A.S. [Departamento de Física Teórica e Experimental, Universidade Federal do Rio Grande do Norte, 59078-900 Natal, RN (Brazil); Medeiros, S.N. de, E-mail: sndemedeiros@gmail.com [Departamento de Física Teórica e Experimental, Universidade Federal do Rio Grande do Norte, 59078-900 Natal, RN (Brazil); Dantas, A.L. [Departamento de Física, Universidade do Estado do Rio Grande do Norte, 59610-210 Mossoró, RN (Brazil)

    2016-05-01

    We report the synthesis of Ca{sub 2}Fe{sub 2}O{sub 5} nanoparticles by high-energy ball milling and thermal annealing from α-Fe{sub 2}O{sub 3} and CaCO{sub 3}. Magnetization measurements, Mössbauer and X-ray spectra reveal that annealing at high temperatures leads to better quality samples. Our results indicate nanoparticles produced by 10 h high-energy ball milling and thermal annealing for 2 h at 1100 °C achieve improved stoichiometry and the full weak ferromagnetic signal of Ca{sub 2}Fe{sub 2}O{sub 5}. Samples annealed at lower temperatures show departure from stoichiometry, with a higher occupancy of Fe{sup 3+} in octahedral sites, and a reduced magnetization. Thermal relaxation for temperatures in the 700–1100 °C range is well represented by a Néel model, assuming a random orientation of the weak ferromagnetic moment of the Ca{sub 2}Fe{sub 2}O{sub 5} nanoparticles.

  6. Laser thermal annealing of Ge, optimized for highly activated dopants and diode ION/IOFF ratios

    DEFF Research Database (Denmark)

    Shayesteh, M.; O'Connell, D.; Gity, F.

    2014-01-01

    and ideality factor (n) approximately 1.2-1.5 was achieved with LTA. However RTA revealed very high ION/IOFF ratio approximately 107, and n close to 1. Non ideal behavior in LTA diodes is attributed to existence of deep level defects in the junction, contributing to leakage current. Meanwhile ideal behavior...... of RTA diodes is due to removal of defects in the junction during the high thermal budget....

  7. Structural stability of hydrogenated amorphous carbon overcoats used in heat-assisted magnetic recording investigated by rapid thermal annealing

    KAUST Repository

    Wang, N.

    2013-01-01

    Ultrathin amorphous carbon (a-C) films are extensively used as protective overcoats of magnetic recording media. Increasing demands for even higher storage densities have necessitated the development of new storage technologies, such as heat-assisted magnetic recording (HAMR), which uses laser-assisted heating to record data on high-stability media that can store single bits in extremely small areas (∼1 Tbit/in.2). Because HAMR relies on locally changing the coercivity of the magnetic medium by raising the temperature above the Curie temperature for data to be stored by the magnetic write field, it raises a concern about the structural stability of the ultrathin a-C film. In this study, rapid thermal annealing (RTA) experiments were performed to examine the thermal stability of ultrathin hydrogenated amorphous carbon (a-C:H) films deposited by plasma-enhanced chemical vapor deposition. Structural changes in the a-C:H films caused by RTA were investigated by x-ray photoelectron spectroscopy, Raman spectroscopy, x-ray reflectivity, and conductive atomic force microscopy. The results show that the films exhibit thermal stability up to a maximum temperature in the range of 400-450 °C. Heating above this critical temperature leads to hydrogen depletion and sp 2 clustering. The critical temperature determined by the results of this study represents an upper bound of the temperature rise due to laser heating in HAMR hard-disk drives and the Curie temperature of magnetic materials used in HAMR hard disks. © 2013 American Institute of Physics.

  8. EFFECT OF PRE-ANNEALING TEMPERATURE ON THE GROWTH OF ALIGNED α-Fe2O3 NANOWIRES VIA A TWO-STEP THERMAL OXIDATION

    Science.gov (United States)

    Rashid, Norhana Mohamed; Kishi, Naoki; Soga, Tetsuo

    2016-03-01

    Pre-annealing as part of a two-step thermal oxidation process has a significant effect on the growth of hematite (α-Fe2O3) nanowires on Fe foil. High-density aligned nanowires were obtained on iron foils pre-annealed at 300∘C under a dry air flow for 30min. The X-ray diffraction (XRD) patterns indicate that the nanowires are transformed from the small α-Fe2O3 grains and uniquely grow in the (110) direction. The formation of a high-density of small grains by pre-annealing improved the alignment and density of the α-Fe2O3 nanowires.

  9. Analysis of Thermal Performance in a Bidirectional Thermocycler by Including Thermal Contact Characteristics

    Directory of Open Access Journals (Sweden)

    Jyh Jian Chen

    2014-12-01

    Full Text Available This paper illustrates an application of a technique for predicting the thermal characteristics of a bidirectional thermocycling device for polymerase chain reaction (PCR. The micromilling chamber is oscillated by a servo motor and contacted with different isothermal heating blocks to successfully amplify the DNA templates. Because a comprehensive database of contact resistance factors does not exist, it causes researchers to not take thermal contact resistance into consideration at all. We are motivated to accurately determine the thermal characteristics of the reaction chamber with thermal contact effects existing between the heater surface and the chamber surface. Numerical results show that the thermal contact effects between the heating blocks and the reaction chamber dominate the temperature variations and the ramping rates inside the PCR chamber. However, the influences of various temperatures of the ambient conditions on the sample temperature during three PCR steps can be negligible. The experimental temperature profiles are compared well with the numerical simulations by considering the thermal contact conductance coefficient which is empirical by the experimental fitting. To take thermal contact conductance coefficients into consideration in the thermal simulation is recommended to predict a reasonable temperature profile of the reaction chamber during various thermal cycling processes. Finally, the PCR experiments present that Hygromycin B DNA templates are amplified successfully. Furthermore, our group is the first group to introduce the thermal contact effect into theoretical study that has been applied to the design of a PCR device, and to perform the PCR process in a bidirectional thermocycler.

  10. Effects of thickness and annealing condition on magnetic properties and thermal stabilities of Ta/Nd/NdFeB/Nd/Ta sandwiched films

    Science.gov (United States)

    Liu, Wen-Feng; Zhang, Min-Gang; Zhang, Ke-Wei; Zhang, Hai-Jie; Xu, Xiao-Hong; Chai, Yue-Sheng

    2016-11-01

    Ta/Nd/NdFeB/Nd/Ta sandwiched films are deposited by magnetron sputtering on Si (100) substrates, and subsequently annealed in vacuum at different temperatures for different time. It is found that both the thickness of NdFeB and Nd layer and the annealing condition can affect the magnetic properties of Ta/Nd/NdFeB/Nd/Ta films. Interestingly, the thickness and annealing temperature show the relevant behaviors that can affect the magnetic properties of the film. The high coercivity of 24.1 kOe (1 Oe = 79.5775 A/m) and remanence ratio (remanent magnetization/saturation magnetization) of 0.94 can be obtained in a Ta/Nd(250 nm)/NdFeB(600 nm)/Nd(250 nm)/Ta film annealed for 3 min at 1023 K. In addition, the thermal stability of the film is also linked to the thickness of NdFeB and Nd layer and the annealing temperature as well. The excellent thermal stability can be achieved in a Ta/Nd(250 nm)/NdFeB(600 nm)/Nd(250 nm)/Ta film annealed at 1023 K. Program supported by the National Natural Science Foundation of China (Grant No. 51305290), the Higher Education Technical Innovation Project of Shanxi Province, China (Grant No. 2013133), the Fund Program for the Scientific Activities of Selected Returned Overseas Professionals of Shanxi Province, China (Grant No. 2015003), and the Program for the Key Team of Scientific and Technological Innovation of Shanxi Province, China (Grant No. 2013131009).

  11. The effect of thermal annealing on the optical band gap of cadmium sulphide thin films, prepared by the chemical bath deposition technique

    International Nuclear Information System (INIS)

    Ampong, F. K.; Boakye, F.; Asare Donkor, N. K.

    2010-01-01

    Cadmium sulphide thin films have been prepared by the chemical bath deposition technique (ph 11, 70 degree centigrade). Two different sets of films were prepared under varied conditions and concentrations of their ions sources (Cd 2+ from cadmium nitrate, S 2- from thiourea) and Na 2 EDTA as a complexing agent. A UV mini-Schimazu UV-VIS Spectrophotometer was used to determine the optical absorbance of the films as a function of wavelength at room temperature over the wavelength range 200 - 600 nm. The samples were then thermally annealed for thirty minutes, at temperatures of 100 degree centigrade, and 200 degree centigrade, after which the absorbance of the films were again recorded. The band gap values obtained for the sample with 0.5 M CdS as deposited, annealed at 100 degree centigrade and 200 degree centigrade were 2.1 eV, 2.2 eV and 2.3 eV respectively. Whilst the values obtained for the sample 0.15 CdS as deposited, annealed at 100 degree centigrade and annealed at 200 degree centigrade were 2.0 eV, 2.01 eV and 2.02 eV respectively. The increase in band gap with annealing temperature might be attributed to the improvement in crystallinity in the films. (au)

  12. Effects of thermal annealing on the radiation produced electron paramagnetic resonance spectra of bovine and equine tooth enamel: Fossil and modern

    International Nuclear Information System (INIS)

    Weeks, Robert A.; Bogard, James S.; Elam, J. Michael; Weinand, Daniel C.; Kramer, Andrew

    2003-01-01

    The concentration of stable radiation-induced paramagnetic states in fossil teeth can be used as a measure of sample age. Temperature excursions >100 deg. C, however, can cause the paramagnetic state clock to differ from the actual postmortem time. We have heated irradiated enamel from both fossilized bovid and modern equine (MEQ) teeth for 30 min in 50 deg. C increments from 100 to 300 deg. C, measuring the electron paramagnetic resonance (EPR) spectrum after each anneal, to investigate such effects. Samples were irradiated again after the last anneal, with doses of 300-1200 Gy from 60 Co photons, and measured. Two unirradiated MEQ samples were also annealed for 30 min at 300 deg. C, one in an evacuated EPR tube and the other in a tube open to the atmosphere, and subsequently irradiated. The data showed that hyperfine components attributed to the alanine radical were not detected in the irradiated MEQ sample until after the anneals. The spectrum of the MEQ sample heated in air and then irradiated was similar to that of the heat treated fossil sample. We conclude that the hyperfine components are due to sample heating to temperatures/times >100 deg. C/30 min and that similarities between fossil and MEQ spectra after the 300 deg. C/30 min MEQ anneal are also due to sample heating. We conclude that the presence of the hyperfine components in spectra of fossil tooth enamel indicate that such thermal events occurred either at the time of death, or during the postmortem history

  13. Photothermal deflection technique investigation of annealing temperature and time effects on optical and thermal conductivity of V/V2O5 alternating layers structure

    Science.gov (United States)

    Khalfaoui, A.; Ilahi, S.; Abdel-Rahman, M.; Zia, M. F.; Alduraibi, M.; Ilahi, B.; Yacoubi, N.

    2017-10-01

    The VxOy material is fabricated by alternating multilayer of V/V2O5. Two sets of VxOy are presented annealed at 300 °C and 400 °C for 20, 30 and 40 min. We have determined optical absorption spectra of the two sets by comparison between experimental and theoretical PDS amplitude signal. In fact, a variation of the bandgap energy from 2.34eV to 2.49 eV has found for both set annealed at 300 °C and 400 °C for various annealing time. The variation of bandgap energy is discussed testifying a structural and compositional change. Moreover, thermal conductivity of the set annealed at 400 °C showed a variation from 1.96 W/m K to 6.2 W/m K noting a decrease up to 2.89 W/m K for that annealed for 30 min.

  14. Effect of thermal annealing on the redistribution of alkali metals in Cu(In,Ga)Se2 solar cells on glass substrate

    Science.gov (United States)

    Kamikawa, Yukiko; Nishinaga, Jiro; Ishizuka, Shogo; Tayagaki, Takeshi; Guthrey, Harvey; Shibata, Hajime; Matsubara, Koji; Niki, Shigeru

    2018-03-01

    The precise control of alkali-metal concentrations in Cu(In,Ga)Se2 (CIGS) solar cells via post deposition treatment (PDT) has recently attracted attention. When PDT is performed at an elevated temperature, an accompanying annealing effect is expected. Here, we investigate how thermal annealing affects the redistribution of alkali metals in CIGS solar cells on glass substrates and the properties of the solar cells. In addition, we investigate the origin of non-homogeneous alkali-metal depth profiles that are typical of CIGS grown using a three-stage process. In particular, we use secondary-ion mass spectrometry measurements of the ion concentration as a function of distance from the CIGS surface to investigate the impact of thermal annealing on the distribution of alkali metals (Na, Ka, and Rb) and constituent elements (Ga and In) in the CIGS absorbers. We find that the depth profiles of the alkali metals strongly reflect the density of sites that tend to accommodate alkali metals, i.e., vacancies. Annealing at elevated temperature caused a redistribution of the alkali metals. The thermal-diffusion kinetics of alkali metals depends strongly on the species involved. We introduced low flux potassium fluoride (KF) to study a side effect of KF-PDT, i.e., Na removal from CIGS, separately from its predominant effects such as surface modification. When sufficient amounts of Na are supplied from the soda lime glass via annealing at an elevated temperature, the negative effect was not apparent. Conversely, when the Na supply was not sufficient, it caused a deterioration of the photovoltaic properties.

  15. Effect of Thermal Annealing on the Redistribution of Alkali Metals in Cu(In,Ga)Se2 Solar Cells on Glass Substrate

    Energy Technology Data Exchange (ETDEWEB)

    Guthrey, Harvey L [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Kamikawa, Yukiko [National Institute of Advanced Industrial Science and Technology (AIST); Nishinaga, Jiro [National Institute of Advanced Industrial Science and Technology (AIST); Ishizuka, Shogo [National Institute of Advanced Industrial Science and Technology (AIST); Tayagaki, Takeshi [National Institute of Advanced Industrial Science and Technology (AIST); Shibata, Hajime [National Institute of Advanced Industrial Science and Technology (AIST); Matsubara, Koji [National Institute of Advanced Industrial Science and Technology (AIST); Niki, Shigeru [National Institute of Advanced Industrial Science and Technology (AIST)

    2018-03-02

    The precise control of alkali-metal concentrations in Cu(In,Ga)Se2 (CIGS) solar cells via post deposition treatment (PDT) has recently attracted attention. When PDT is performed at an elevated temperature, an accompanying annealing effect is expected. Here, we investigate how thermal annealing affects the redistribution of alkali metals in CIGS solar cells on glass substrates and the properties of the solar cells. In addition, we investigate the origin of non-homogeneous alkali-metal depth profiles that are typical of CIGS grown using a three-stage process. In particular, we use secondary-ion mass spectrometry measurements of the ion concentration as a function of distance from the CIGS surface to investigate the impact of thermal annealing on the distribution of alkali metals (Na, Ka, and Rb) and constituent elements (Ga and In) in the CIGS absorbers. We find that the depth profiles of the alkali metals strongly reflect the density of sites that tend to accommodate alkali metals, i.e., vacancies. Annealing at elevated temperature caused a redistribution of the alkali metals. The thermal-diffusion kinetics of alkali metals depends strongly on the species involved. We introduced low flux potassium fluoride (KF) to study a side effect of KF-PDT, i.e., Na removal from CIGS, separately from its predominant effects such as surface modification. When sufficient amounts of Na are supplied from the soda lime glass via annealing at an elevated temperature, the negative effect was not apparent. Conversely, when the Na supply was not sufficient, it caused a deterioration of the photovoltaic properties.

  16. Electrical characteristics and preparation of (Ba0.5Sr0.5)TiO3 films by spray pyrolysis and rapid thermal annealing

    International Nuclear Information System (INIS)

    Koo, Horngshow; Ku, Hongkou; Kawai, Tomoji; Chen Mi

    2007-01-01

    Functional films of (Ba 0.5 Sr 0.5 )TiO 3 on Pt (1000 A)/Ti (100 A)/SiO 2 (2000 A)/Si substrates are prepared by spray pyrolysis and subsequently rapid thermal annealing. Barium nitrate, strontium nitrate and titanium isopropoxide are used as starting materials with ethylene glycol as solvent. For (Ba 0.5 Sr 0.5 )TiO 3 functional thin film, thermal characteristics of the precursor powder scratched from as-sprayed films show a remarkable peak around 300-400degC and 57.7% weight loss up to 1000degC. The as-sprayed precursor film with coffee-like color and amorphous-like phase is transformed into the resultant film with white, crystalline perovskite phase and characteristic peaks (110) and (100). The resultant films show correspondent increases of dielectric constant, leakage current and dissipation factor with increasing annealing temperatures. The dielectric constant is 264 and tangent loss is 0.21 in the resultant films annealed at 750degC for 5 min while leakage current density is 1.5x10 -6 A/cm 2 in the film annealed at 550degC for 5 min. (author)

  17. Studies of thermal annealing and dope composition on the enhancement of separation performance cellulose acetate membrane for brackish water treatment from Jepara

    Directory of Open Access Journals (Sweden)

    Tutuk Djoko Kusworo

    2014-08-01

    Full Text Available Membrane is an alternative technology of water treatment with filtration principle that is being widely developed and used for water treatment. The main objective of this study was to make an asymmetric membrane using cellulose acetate polymer and study the effect of additive and annealing treatment on the morphology structure and performance of cellulose acetate membranes in brackish water treatment. Asymmetric membranes for brackish water treatment were casted using a casting machine process from dope solutions containing cellulose acetates and acetone as a solvent. Membranes was prepared by phase inversion method  with variation of polyethylene glycol (PEG concentration of 1 and 5 wt% and with thermal annealing at 60 oC in 10 seconds and without thermal annealing behavior. Membrane characterization consists of calculation of membrane flux and rejection with brackish water as a feed from Jepara. The research concluded that asymmetric cellulose acetate membrane can be made by dry/wet phase inversion method. The more added concentration of PEG will be resulted the larger pore of membrane. Meanwhile the higher temperature and the longer time of annealing treatment, the skin layer of membrane become denser. Membrane with the composition of 18 wt% cellulose acetate, 5 wt% PEG, 1 wt% distilled water, with heat treatment at temperature of 60 oC for 10 seconds is obtained optimal performance.

  18. Catalyst-free synthesis of nitrogen-doped graphene via thermal annealing graphite oxide with melamine and its excellent electrocatalysis.

    Science.gov (United States)

    Sheng, Zhen-Huan; Shao, Lin; Chen, Jing-Jing; Bao, Wen-Jing; Wang, Feng-Bin; Xia, Xing-Hua

    2011-06-28

    The electronic and chemical properties of graphene can be modulated by chemical doping foreign atoms and functional moieties. The general approach to the synthesis of nitrogen-doped graphene (NG), such as chemical vapor deposition (CVD) performed in gas phases, requires transitional metal catalysts which could contaminate the resultant products and thus affect their properties. In this paper, we propose a facile, catalyst-free thermal annealing approach for large-scale synthesis of NG using low-cost industrial material melamine as the nitrogen source. This approach can completely avoid the contamination of transition metal catalysts, and thus the intrinsic catalytic performance of pure NGs can be investigated. Detailed X-ray photoelectron spectrum analysis of the resultant products shows that the atomic percentage of nitrogen in doped graphene samples can be adjusted up to 10.1%. Such a high doping level has not been reported previously. High-resolution N1s spectra reveal that the as-made NG mainly contains pyridine-like nitrogen atoms. Electrochemical characterizations clearly demonstrate excellent electrocatalytic activity of NG toward the oxygen reduction reaction (ORR) in alkaline electrolytes, which is independent of nitrogen doping level. The present catalyst-free approach opens up the possibility for the synthesis of NG in gram-scale for electronic devices and cathodic materials for fuel cells and biosensors.

  19. Rapid Thermal Annealing and Hydrogen Passivation of Polycrystalline Silicon Thin-Film Solar Cells on Low-Temperature Glass

    Directory of Open Access Journals (Sweden)

    Mason L. Terry

    2007-01-01

    Full Text Available The changes in open-circuit voltage (Voc, short-circuit current density (Jsc, and internal quantum efficiency (IQE of aLuminum induced crystallization, ion-assisted deposition (ALICIA polycrystalline silicon thin-film solar cells on low-temperature glass substrates due to rapid thermal anneal (RTA treatment and subsequent remote microwave hydrogen plasma passivation (hydrogenation are examined. Voc improvements from 130 mV to 430 mV, Jsc improvements from 1.2 mA/cm2 to 11.3 mA/cm2, and peak IQE improvements from 16% to > 70% are achieved. A 1-second RTA plateau at 1000°C followed by hydrogenation increases the Jsc by a factor of 5.5. Secondary ion mass spectroscopy measurements are used to determine the concentration profiles of dopants, impurities, and hydrogen. Computer modeling based on simulations of the measured IQE data reveals that the minority carrier lifetime in the absorber region increases by 3 orders of magnitude to about 1 nanosecond (corresponding to a diffusion length of at least 1 μm due to RTA and subsequent hydrogenation. The evaluation of the changes in the quantum efficiency and Voc due to RTA and hydrogenation with computer modeling significantly improves the understanding of the limiting factors to cell performance.

  20. Investigations of rapid thermal annealing induced structural evolution of ZnO: Ge nanocomposite thin films via GISAXS

    Energy Technology Data Exchange (ETDEWEB)

    Ceylan, Abdullah, E-mail: aceylanabd@yahoo.com [Department of Physics Eng., Hacettepe University, Beytepe, 06800 Ankara (Turkey); Ozcan, Yusuf [Department of Electricity and Energy, Pamukkale University, Denizli (Turkey); Orujalipoor, Ilghar [Department of Nanotechnology and Nanomedicine, Hacettepe University, Beytepe, 06800 Ankara (Turkey); Huang, Yen-Chih; Jeng, U-Ser [National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu Science Park, Hsinchu, Taiwan (China); Ide, Semra [Department of Physics Eng., Hacettepe University, Beytepe, 06800 Ankara (Turkey); Department of Nanotechnology and Nanomedicine, Hacettepe University, Beytepe, 06800 Ankara (Turkey)

    2016-06-07

    In this work, we present in depth structural investigations of nanocomposite ZnO: Ge thin films by utilizing a state of the art grazing incidence small angle x-ray spectroscopy (GISAXS) technique. The samples have been deposited by sequential r.f. and d.c. sputtering of ZnO and Ge thin film layers, respectively, on single crystal Si(100) substrates. Transformation of Ge layers into Ge nanoparticles (Ge-np) has been initiated by ex-situ rapid thermal annealing of asprepared thin film samples at 600 °C for 30, 60, and 90 s under forming gas atmosphere. A special attention has been paid on the effects of reactive and nonreactive growth of ZnO layers on the structural evolution of Ge-np. GISAXS analyses have been performed via cylindrical and spherical form factor calculations for different nanostructure types. Variations of the size, shape, and distributions of both ZnO and Ge nanostructures have been determined. It has been realized that GISAXS results are not only remarkably consistent with the electron microscopy observations but also provide additional information on the large scale size and shape distribution of the nanostructured components.

  1. Formation of silicon nanoislands on crystalline silicon substrates by thermal annealing of silicon rich oxide deposited by low pressure chemical vapour deposition

    International Nuclear Information System (INIS)

    Yu Zhenrui; Aceves-Mijares, Mariano; Luna-Lopez, A; Du Jinhui; Bian Dongcai

    2006-01-01

    We report the preparation and characterization of Si nanoislands grown on a c-Si substrate by thermal annealing of silicon-rich oxide (SRO) films deposited using a conventional low pressure chemical vapour deposition (LPCVD) technique. Transmission electron microscopy revealed that a high density of Si nanoislands was formed on the surface of the c-Si substrate during thermal annealing. The nanoislands are nanocrystallites with the same crystal orientation as the substrate. The strain at the c-Si/SRO interface is probably the main reason for the nucleation of the self-assembled Si nanoislands that epitaxially grow on the c-Si substrate. The proposed method is very simple and compatible with Si integrated circuit technology

  2. Energy band structure tailoring of vertically aligned InAs/GaAsSb quantum dot structure for intermediate-band solar cell application by thermal annealing process.

    Science.gov (United States)

    Liu, Wei-Sheng; Chu, Ting-Fu; Huang, Tien-Hao

    2014-12-15

    This study presents an band-alignment tailoring of a vertically aligned InAs/GaAs(Sb) quantum dot (QD) structure and the extension of the carrier lifetime therein by rapid thermal annealing (RTA). Arrhenius analysis indicates a larger activation energy and thermal stability that results from the suppression of In-Ga intermixing and preservation of the QD heterostructure in an annealed vertically aligned InAs/GaAsSb QD structure. Power-dependent and time-resolved photoluminescence were utilized to demonstrate the extended carrier lifetime from 4.7 to 9.4 ns and elucidate the mechanisms of the antimony aggregation resulting in a band-alignment tailoring from straddling to staggered gap after the RTA process. The significant extension in the carrier lifetime of the columnar InAs/GaAsSb dot structure make the great potential in improving QD intermediate-band solar cell application.

  3. Directed Self-Assembly of Polystyrene- b -poly(propylene carbonate) on Chemical Patterns via Thermal Annealing for Next Generation Lithography

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Guan-Wen [MOE Laboratory of; Wu, Guang-Peng [MOE Laboratory of; Chen, Xuanxuan [Institute for Molecular Engineering, University of Chicago, Chicago, Illinois 60637, United States; Xiong, Shisheng [Institute for Molecular Engineering, University of Chicago, Chicago, Illinois 60637, United States; Materials Science Division, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, Illinois 60439, United States; Arges, Christopher G. [Cain Department; Ji, Shengxiang [Key Laboratory of Polymer Ecomaterials,; Nealey, Paul F. [Institute for Molecular Engineering, University of Chicago, Chicago, Illinois 60637, United States; Materials Science Division, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, Illinois 60439, United States; Lu, Xiao-Bing [State Key Laboratory of; Darensbourg, Donald J. [Department of Chemistry, Texas A& amp,M University, 3255 TAMU, College Station, Texas 77843, United States; Xu, Zhi-Kang [MOE Laboratory of

    2017-01-23

    Directed self-assembly (DSA) of block copolymers (BCPs) combines advantages of conventional photolithography and polymeric materials and shows competence in semiconductors and data storage applications. Driven by the more integrated, much smaller and higher performance of the electronics, however, the industry standard polystyrene-block-poly(methyl methacrylate) (PS-b-PMM.A) in DSA strategy cannot meet the rapid development of lithography technology because its intrinsic limited Flory-Huggins interaction parameter (chi). Despite hundreds of block copolymers have been developed, these BCPs systems are usually subject to a trade-off between high chi and thermal treatment, resulting in incompatibility with the current nanomanufacturing fab processes. Here we discover that polystyrene-b-poly(propylene carbonate) (PS-b-PPC) is well qualified to fill key positions on DSA strategy for the next-generation lithography. The estimated chi-value for PS-b-PPC is 0.079, that is, two times greater than PS-b-PMMA (chi = 0.029 at 150 degrees C), while processing the ability to form perpendicular sub-10 nm morphologies (cylinder and lamellae) via the industry preferred thermal-treatment. DSA of lamellae forming PS-b-PPC on chemoepitaxial density multiplication demonstrates successful sub-10 nm long-range order features on large-area patterning for nanofabrication. Pattern transfer to the silicon substrate through industrial sequential infiltration synthesis is also implemented successfully. Compared with the previously reported methods to orientation control BCPs with high chi-value (including solvent annealing, neutral top-coats, and chemical modification), the easy preparation, high chi value, and etch selectivity while enduring thermal treatment demonstrates PS-b-PPC as a rare and valuable candidate for advancing the field of nanolithography.

  4. The effect of pre-heating and pre-irradiation with gamma-rays on thermal annealing in-bis-[n-benzoil-n-(o) tolylhydroxylaminate] cooper (II)

    International Nuclear Information System (INIS)

    Nakanishi, C.; Silva, C.P.G. da.

    1990-02-01

    The main purpose of this work was to make a contribution on the study of the chemical effects of the (N,γ) reaction on copper chelate. The influence of some factors such as pre-heating and pre-irradiation with gama-rays on the retention and thermal annealing of bis [N-benzoyl-N-(o)tolylhydroxylaminate] copper (II) was investigated. The complex was synthesized and later characterized by means of: determination of the melting-point, elemental analysis, infra-red and visible range absortion spectrophotometry. The compound was heated and also irradiated with gamma-rays in order to verify the effect of thermolysis on the retention. It seems that heat and gamma-radiaition can produce deffects which will lower the susceptibility of the compound to thermal annealling. On the basis on the model envolving electronic species some explanation of ours results were made and a mechanism was proposed for the retention and thermal annealing assuming the capture of free electrons and also the existence of holes. (author) [pt

  5. The effect of pre-heating and pre-irradiation with gamma rays on thermal annealing in bis [n-benzoil-n-phenyl hydroxilaminate] copper (II)

    International Nuclear Information System (INIS)

    Nakanishi, C.; Silva, C.P.G. da.

    1988-10-01

    The main purpose of this work was to make a contribution to the study of the chemical effects of the (n,γ) reaction on copper chelate. The influence of some factors such as pre-heating and pre-irradiation with gamma-rays on the retention and thermal annealing of bis-[N-benzoil-N-phenlhydroxilaminate] copper (II) was investigated. The complex was synthesized and later characterized by means of: determination of the melting-Point, elemental analysis, infra-red and vesible range absortion spectrophotometry. The compound was heated and also irradiated with gamma-rays in order to verify the effect of thermolysis and radiolysis on the retention. It seems that heat gamma-radiation can produce deffects which will lower the susceptibility of the compound to thermal annealing. On the model envolving electronic species some explanation of ours results were made and a mechanism was proposed for the retention and thermal annealing aasuming the capture of free electrons and also the existence of holes. (author) [pt

  6. Effect of thermal annealing on the optical and electronic properties of ZnO thin films grown on p-Si substrates

    Energy Technology Data Exchange (ETDEWEB)

    Han, W.G. [Department of Materials Science and Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Kang, S.G. [Department of Materials Science and Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Kim, T.W. [Advanced Semiconductor Research Center, Division of Electrical and Computer Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of)]. E-mail: twk@hanyang.ac.kr; Kim, D.W. [Semiconductor Materials Laboratory, Nano-Device Research Center, Korea Institute of Science and Technology, P.O. Box 131, Cheongryang, Seoul 130-650 (Korea, Republic of); Cho, W.J. [Semiconductor Materials Laboratory, Nano-Device Research Center, Korea Institute of Science and Technology, P.O. Box 131, Cheongryang, Seoul 130-650 (Korea, Republic of)

    2005-05-30

    The effects of annealing on the optical and the electronics properties of ZnO thin films grown on p-Si(1 0 0) substrates by using radio frequency magnetron sputtering were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), photoluminescence (PL), and X-ray photoelectron spectroscopy (XPS) measurements. The XRD patterns and pole figures showed that the crystallinity of the ZnO films grown on p-Si(1 0 0) substrates was improved by thermal treatment. XRD patterns, pole figures, and TEM images showed that the as-grown and the annealed ZnO films grown on Si(1 0 0) substrates had a c-axis preferential orientation in the [0 0 0 1] crystal direction. The PL spectra showed that luminescence peaks related to the free excitons and the deep levels appeared after annealing. The XPS spectra showed that the peak positions corresponding to the O 1s and the Zn 2p shifted slightly after thermal treatment. These results can help improve understanding of thermal effects on the optical and the electronic properties of ZnO thin films grown on p-Si(1 0 0) substrates.

  7. Effects of Rapid Thermal Annealing on the Structural, Electrical, and Optical Properties of Zr-Doped ZnO Thin Films Grown by Atomic Layer Deposition

    Directory of Open Access Journals (Sweden)

    Jingjin Wu

    2016-08-01

    Full Text Available The 4 at. % zirconium-doped zinc oxide (ZnO:Zr films grown by atomic layer deposition (ALD were annealed at various temperatures ranging from 350 to 950 °C. The structural, electrical, and optical properties of rapid thermal annealing (RTA treated ZnO:Zr films have been evaluated to find out the stability limit. It was found that the grain size increased at 350 °C and decreased between 350 and 850 °C, while creeping up again at 850 °C. UV–vis characterization shows that the optical band gap shifts towards larger wavelengths. The Hall measurement shows that the resistivity almost keeps constant at low annealing temperatures, and increases rapidly after treatment at 750 °C due to the effect of both the carrier concentration and the Hall mobility. The best annealing temperature is found in the range of 350–550 °C. The ZnO:Zr film-coated glass substrates show good optical and electrical performance up to 550 °C during superstrate thin film solar cell deposition.

  8. Effect of rapid thermal annealing on the Mo back contact properties for Cu2ZnSnSe4 solar cells

    International Nuclear Information System (INIS)

    Placidi, Marcel; Espindola-Rodriguez, Moises; Lopez-Marino, Simon; Sanchez, Yudania; Giraldo, Sergio; Acebo, Laura; Neuschitzer, Markus; Alcobé, Xavier; Pérez-Rodríguez, Alejandro; Saucedo, Edgardo

    2016-01-01

    The effect of a rapid thermal process (RTP) on the molybdenum (Mo) back contact for Cu 2 ZnSnSe 4 (CZTSe) solar cells is here investigated. It is shown that the annealing of the Mo layer during 5 min at 550 °C, not only improves the crystalline quality of the back contact (avoiding the absorber decomposition at this region because Mo becomes more resistant to the selenization), but also helps achieving higher crystalline quality of the absorber with bigger grains, reducing the current leakage through the heterojunction. We demonstrate that this is related to the relaxation of the compressive stress of the CZTSe absorber, when synthesized on the RTP annealed substrates. CZTSe solar cells prepared on annealed Mo films exhibited higher short circuit current densities and higher open circuit voltages, resulting in 10% and 33% higher fill factors and efficiencies. - Highlights: • An RTP annealing applied for the first time on Mo for CZTSe solar cells. • Clear improvement of the efficiency from 5.7 to 7.6% with RTP treatment. • Discussion of this improvement with adequate material/device characterizations. • Stress-induced defects responsible of the electrical leakage are revealed.

  9. Effects of Rapid Thermal Annealing on the Structural, Electrical, and Optical Properties of Zr-Doped ZnO Thin Films Grown by Atomic Layer Deposition.

    Science.gov (United States)

    Wu, Jingjin; Zhao, Yinchao; Zhao, Ce Zhou; Yang, Li; Lu, Qifeng; Zhang, Qian; Smith, Jeremy; Zhao, Yongming

    2016-08-13

    The 4 at. % zirconium-doped zinc oxide (ZnO:Zr) films grown by atomic layer deposition (ALD) were annealed at various temperatures ranging from 350 to 950 °C. The structural, electrical, and optical properties of rapid thermal annealing (RTA) treated ZnO:Zr films have been evaluated to find out the stability limit. It was found that the grain size increased at 350 °C and decreased between 350 and 850 °C, while creeping up again at 850 °C. UV-vis characterization shows that the optical band gap shifts towards larger wavelengths. The Hall measurement shows that the resistivity almost keeps constant at low annealing temperatures, and increases rapidly after treatment at 750 °C due to the effect of both the carrier concentration and the Hall mobility. The best annealing temperature is found in the range of 350-550 °C. The ZnO:Zr film-coated glass substrates show good optical and electrical performance up to 550 °C during superstrate thin film solar cell deposition.

  10. Thermal annealing effects on the interface state density of metal-oxide-semiconductor capacitors with electron cyclotron resonance plasma enhanced chemical vapor deposition Silicon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Maiolo, L. [Istituto di Fotonica e Nanotecnologie (IFN), CNR, Via Cineto Romano 42, 00156 Rome (Italy)], E-mail: lmaiolo@ifn.cnr.it; Pecora, A.; Cuscuna, M.; Fortunato, G. [Istituto di Fotonica e Nanotecnologie (IFN), CNR, Via Cineto Romano 42, 00156 Rome (Italy)

    2007-07-16

    Silicon dioxide films (SiO{sub 2}), deposited at room temperature by electron cyclotron resonance (ECR) plasma reactor from a gas phase combination of O{sub 2}, SiH{sub 4} and He, present excellent structural and electrical properties. However, when fabricating field effect devices it is also crucial to minimize the defect density at the semiconductor/insulator interface. We show that the interface state density, investigated in Al/SiO{sub 2}/Si MOS capacitors, can be substantially reduced performing post-deposition annealing. In particular we studied the effects of annealing temperature and time in different gas ambient: vacuum, nitrogen and forming gas (5% H{sub 2} + N{sub 2}). We found that interface state passivation mainly occurs when thermal annealing is performed after Al-contact deposition and that it is quite insensitive to the annealing atmosphere. The present results clearly suggest that the hydrogen passivation mechanism is driven by the H-containing species present in the film and a possible mechanism to explain the results is proposed.

  11. Thermal annealing effects on the interface state density of metal-oxide-semiconductor capacitors with electron cyclotron resonance plasma enhanced chemical vapor deposition Silicon dioxide

    International Nuclear Information System (INIS)

    Maiolo, L.; Pecora, A.; Cuscuna, M.; Fortunato, G.

    2007-01-01

    Silicon dioxide films (SiO 2 ), deposited at room temperature by electron cyclotron resonance (ECR) plasma reactor from a gas phase combination of O 2 , SiH 4 and He, present excellent structural and electrical properties. However, when fabricating field effect devices it is also crucial to minimize the defect density at the semiconductor/insulator interface. We show that the interface state density, investigated in Al/SiO 2 /Si MOS capacitors, can be substantially reduced performing post-deposition annealing. In particular we studied the effects of annealing temperature and time in different gas ambient: vacuum, nitrogen and forming gas (5% H 2 + N 2 ). We found that interface state passivation mainly occurs when thermal annealing is performed after Al-contact deposition and that it is quite insensitive to the annealing atmosphere. The present results clearly suggest that the hydrogen passivation mechanism is driven by the H-containing species present in the film and a possible mechanism to explain the results is proposed

  12. Effect of Pre-Annealing on Thermal and Optical Properties of ZnO and Al-ZnO Thin Films

    Science.gov (United States)

    Saravanan, P.; Gnanavelbabu, A.; Pandiaraj, P.

    Zinc oxide (ZnO) nanoparticles were synthesized by a simple solution route method using zinc acetate as the precursor and ethanol as the solvent. At a temperature of 60∘C, a clear homogenous solution is heated to 100∘C for ethanol evaporation. Then the obtained precursor powder is annealed at 600∘C for the formation of ZnO nanocrystalline structure. Doped ZnO particle is also prepared by using aluminum nitrate nonahydrate to produce aluminum (Al)-doped nanoparticles using the same solution route method followed by annealing. Thin film fabrication is done by air evaporation method using the polymer polyvinyl alcohol (PVA). To analyze the optical and thermal properties for undoped and doped ZnO nanocrystalline thin film by precursor annealing, characterizations such as UV, FTIR, AFM, TGA/DTA, XRD, EDAX and Photoluminescence (PL) were also taken. It was evident that precursor annealing had great influence on thermal and optical properties of thin films while ZnO and AZO film showed low crystallinity and intensity than in the powder form. TGA/DTA suggests pre-annealing effect improves the thermal stability, which ensures that Al ZnO nanoparticle can withstand at high temperature too which is the crucial advantage in the semiconductor devices. UV spectroscopy confirmed the presence of ZnO nanoparticles in the thin film by an absorbance peak observed at 359nm with an energy bandgap of 3.4eV. A peak obtained at 301nm with an energy bandgap of 4.12eV shows a blue shift due to the presence of Al-doped ZnO nanoparticles. Both ZnO and AZO bandgap increased due to precursor annealing. In this research, PL spectrum is also studied in order to determine the optical property of the nanoparticle embedded thin film. From PL spectrum, it is observed that the intensity of the doped ZnO is much more enhanced as the dopant concentration is increased to 1wt.% and 2wt.% of Al in ZnO.

  13. Formation of shallow junctions for VLSI by ion implantation and rapid thermal annealing

    International Nuclear Information System (INIS)

    Oeztuerk, M.C.

    1988-01-01

    In this work, several techniques were studied to form shallow junctions in silicon by ion implantation. These include ion implantation through thin layers of silicon dioxide and ion implantation through a thick polycrystalline silicon layer. These techniques can be used to reduce the junction depth. Their main disadvantage is dopant loss in the surface layer. As an alternative, preamorphization of the Si substrate prior to boron implantation to reduce boron channeling was investigated. The disadvantage of preamorphization is the radiation damage introduced into the Si substrate using the implant. Preamorphization by silicon self-implantation has been studied before. The goal of this study was to test Ge as an alternative amorphizing agent. It was found that good-quality p + -n junctions can be formed by both boron and BF 2 ion implantation into Ge-preamorphized Si provided that the preamorphization conditions are optimized. If the amorphous crystalline interface is sufficiently close to the surface, it is possible to completely remove the end-of-range damage. If these defects are not removed and are left in the depletion region, they can result in poor-quality, leaky junctions

  14. Electrical, optical, and photoluminescence properties of ZnO films subjected to thermal annealing and treatment in hydrogen plasma

    Energy Technology Data Exchange (ETDEWEB)

    Abdullin, Kh. A.; Gabdullin, M. T. [al-Farabi Kazakh National University, National Nanotechnology Laboratory of Open Type (Kazakhstan); Gritsenko, L. V. [Kazakh National Technical Research University (Kazakhstan); Ismailov, D. V.; Kalkozova, Zh. K. [al-Farabi Kazakh National University, National Nanotechnology Laboratory of Open Type (Kazakhstan); Kumekov, S. E., E-mail: skumekov@mail.ru; Mukash, Zh. O. [Kazakh National Technical Research University (Kazakhstan); Sazonov, A. Yu. [200 University Avenue West, University of Waterloo (Canada); Terukov, E. I. [Russian Academy of Sciences, Ioffe Physical–Technical Institute (Russian Federation)

    2016-08-15

    The photoluminescence and optical absorption spectra and electrical properties of ZnO films grown by the metal–organic chemical vapor deposition and hydrothermal techniques, subjected to heat treatments and plasma treatment in a hydrogen atmosphere, are studied. It is shown that the adsorption of oxygen at grain boundaries upon annealing in an oxidizing atmosphere determines the electrical properties of the films. Vacuum annealing improves the electrical properties of the samples after degradation induced by annealing in air. Treatment in hydrogen plasma passivates surface states at the grain boundaries. The intrinsic photoluminescence intensity after plasma treatment is higher in the case of increased amounts of oxygen adsorbed at grain surfaces upon annealing in air. Surface states involving oxygen and hydrogen atoms are responsible for the high-intensity intrinsic photoluminescence band.

  15. Effect of thermal annealing on structural properties of GeSn thin films grown by molecular beam epitaxy

    Science.gov (United States)

    Zhang, Z. P.; Song, Y. X.; Li, Y. Y.; Wu, X. Y.; Zhu, Z. Y. S.; Han, Y.; Zhang, L. Y.; Huang, H.; Wang, S. M.

    2017-10-01

    GeSn alloy with 7.68% Sn concentration grown by molecular beam epitaxy has been rapidly annealed at different temperatures from 300°C to 800°C. Surface morphology and roughness annealed below or equal to 500°C for 1 min have no obvious changes, while the strain relaxation rate increasing. When the annealing temperature is above or equal to 600°C, significant changes occur in surface morphology and roughness, and Sn precipitation is observed at 700°C. The structural properties are analyzed by reciprocal space mapping in the symmetric (004) and asymmetric (224) planes by high resolution X-ray diffraction. The lateral correlation length and the mosaic spread are extracted for the epi-layer peaks in the asymmetric (224) diffraction. The most suitable annealing temperature to improve both the GeSn lattice quality and relaxation rate is about 500°C.

  16. Microstructural evolution of Au/TiO{sub 2} nanocomposite films: The influence of Au concentration and thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Borges, J., E-mail: joelborges@fisica.uminho.pt [Instituto Pedro Nunes, Laboratório de Ensaios, Desgaste e Materiais, Rua Pedro Nunes, 3030-199 Coimbra (Portugal); SEG-CEMUC, Mechanical Engineering Department, University of Coimbra, 3030-788 Coimbra (Portugal); Centro/Departamento de Física, Universidade do Minho, Campus de Gualtar, 4710-057 Braga (Portugal); Kubart, T.; Kumar, S.; Leifer, K. [Solid-State Electronics, Department of Engineering Sciences, Uppsala University, P.O. Box 534, Uppsala SE-751 21 (Sweden); Rodrigues, M.S. [Instituto Pedro Nunes, Laboratório de Ensaios, Desgaste e Materiais, Rua Pedro Nunes, 3030-199 Coimbra (Portugal); Centro/Departamento de Física, Universidade do Minho, Campus de Gualtar, 4710-057 Braga (Portugal); Duarte, N.; Martins, B.; Dias, J.P. [Instituto Pedro Nunes, Laboratório de Ensaios, Desgaste e Materiais, Rua Pedro Nunes, 3030-199 Coimbra (Portugal); Cavaleiro, A. [SEG-CEMUC, Mechanical Engineering Department, University of Coimbra, 3030-788 Coimbra (Portugal); Vaz, F. [SEG-CEMUC, Mechanical Engineering Department, University of Coimbra, 3030-788 Coimbra (Portugal); Centro/Departamento de Física, Universidade do Minho, Campus de Gualtar, 4710-057 Braga (Portugal)

    2015-04-01

    Nanocomposite thin films consisting of a dielectric matrix, such as titanium oxide (TiO{sub 2}), with embedded gold (Au) nanoparticles were prepared and will be analysed and discussed in detail in the present work. The evolution of morphological and structural features was studied for a wide range of Au concentrations and for annealing treatments in air, for temperatures ranging from 200 to 800 °C. Major findings revealed that for low Au atomic concentrations (at.%), there are only traces of clustering, and just for relatively high annealing temperatures, T ≥ 500 °C. Furthermore, the number of Au nanoparticles is extremely low, even for the highest annealing temperature, T = 800 °C. It is noteworthy that the TiO{sub 2} matrix also crystallizes in the anatase phase for annealing temperatures above 300 °C. For intermediate Au contents (5 at.% ≤ C{sub Au} ≤ 15 at.%), the formation of gold nanoclusters was much more evident, beginning at lower annealing temperatures (T ≥ 200 °C) with sizes ranging from 2 to 25 nm as the temperature increased. A change in the matrix crystallization from anatase to rutile was also observed in this intermediate range of compositions. For the highest Au concentrations (> 20 at.%), the films tended to form relatively larger clusters, with sizes above 20 nm (for T ≥ 400 °C). It is demonstrated that the structural and morphological characteristics of the films are strongly affected by the annealing temperature, as well as by the particular amounts, size and distribution of the Au nanoparticles dispersed in the TiO{sub 2} matrix. - Highlights: • Au:TiO{sub 2} films were produced by magnetron sputtering and post-deposition annealing. • The Au concentration in the films increases with the Au pellet area. • Annealing induced microstructural changes in the films. • The nanoparticle size evolution with temperature depends on the Au concentration.

  17. Thermal Insulation System for Non-Vacuum Applications Including a Multilayer Composite

    Science.gov (United States)

    Fesmire, James E. (Inventor)

    2017-01-01

    The thermal insulation system of the present invention is for non-vacuum applications and is specifically tailored to the ambient pressure environment with any level of humidity or moisture. The thermal insulation system includes a multilayered composite including i) at least one thermal insulation layer and at least one compressible barrier layer provided as alternating, successive layers, and ii) at least one reflective film provided on at least one surface of the thermal insulation layer and/or said compressible barrier layer. The different layers and materials and their combinations are designed to provide low effective thermal conductivity for the system by managing all modes of heat transfer. The thermal insulation system includes an optional outer casing surrounding the multilayered composite. The thermal insulation system is particularly suited for use in any sub-ambient temperature environment where moisture or its adverse effects are a concern. The thermal insulation system provides physical resilience against damaging mechanical effects including compression, flexure, impact, vibration, and thermal expansion/contraction.

  18. Impact of thermal annealing on wettability and antifouling characteristics of alginate poly-l-lysine polyelectrolyte multilayer films.

    Science.gov (United States)

    Diamanti, Eleftheria; Muzzio, Nicolas; Gregurec, Danijela; Irigoyen, Joseba; Pasquale, Miguel; Azzaroni, Omar; Brinkmann, Martin; Moya, Sergio Enrique

    2016-09-01

    Polyelectrolyte multilayers (PEMs) of poly-l-lysine (PLL) and alginic acid sodium salt (Alg) are fabricated applying the layer by layer technique and annealed at a constant temperature; 37, 50 and 80°C, for 72h. Atomic force microscopy reveals changes in the topography of the PEM, which is changing from a fibrillar to a smooth surface. Advancing contact angle in water varies from 36° before annealing to 93°, 77° and 95° after annealing at 37, 50 and 80°C, respectively. Surface energy changes after annealing were calculated from contact angle measurements performed with organic solvents. Quartz crystal microbalance with dissipation, contact angle and fluorescence spectroscopy measurements show a significant decrease in the adsorption of the bovine serum albumin protein to the PEMs after annealing. Changes in the physical properties of the PEMs are interpreted as a result of the reorganization of the polyelectrolytes in the PEMs from a layered structure into complexes where the interaction of polycations and polyanions is enhanced. This work proposes a simple method to endow bio-PEMs with antifouling characteristics and tune their wettability. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Effect of thermal annealing on electron spin relaxation of beryllium-doped In{sub 0.8}Ga{sub 0.2}As{sub 0.45}P{sub 0.55} bulk

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Hao; Harasawa, Ryo; Yasue, Yuya; Aritake, Takanori; Jiang, Canyu; Tackeuchi, Atsushi, E-mail: atacke@waseda.jp [Department of Applied Physics, Waseda University, Shinjuku, Tokyo 169-8555 (Japan); Ji, Lian; Lu, Shulong [Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Dushu Lake Higher Education Town, Ruoshui Road 398, Suzhou Industrial Park, Suzhou (China)

    2016-08-15

    The effect of thermal annealing on the electron spin relaxation of beryllium-doped In{sub 0.8}Ga{sub 0.2}As{sub 0.45}P{sub 0.55} bulk was investigated by time-resolved spin-dependent pump and probe reflection measurement with a high time resolution of 200 fs. Three similar InGaAsP samples were examined one of which was annealed at 800 °C for 1 s, one was annealed at 700 °C for 1 s and the other was not annealed after crystal growth by molecular beam epitaxy. Although the carrier lifetimes of the 700 °C-annealed sample and the unannealed sample were similar, that of the 800 °C-annealed sample was extended to 11.6 (10.4) ns at 10 (300) K, which was more than two (four) times those of the other samples. However, interestingly the spin relaxation time of the 800 °C-annealed sample was found to be similar to those of the other two samples. Particularly at room temperature, the spin relaxation times are 143 ps, 147 ps, and 111 ps for the 800 °C-annealed sample, 700 °C-annealed sample, and the unannealed sample, respectively.

  20. Effect of thermal annealing on electron spin relaxation of beryllium-doped In0.8Ga0.2As0.45P0.55 bulk

    Directory of Open Access Journals (Sweden)

    Hao Wu

    2016-08-01

    Full Text Available The effect of thermal annealing on the electron spin relaxation of beryllium-doped In0.8Ga0.2As0.45P0.55 bulk was investigated by time-resolved spin-dependent pump and probe reflection measurement with a high time resolution of 200 fs. Three similar InGaAsP samples were examined one of which was annealed at 800 °C for 1 s, one was annealed at 700 °C for 1 s and the other was not annealed after crystal growth by molecular beam epitaxy. Although the carrier lifetimes of the 700 °C-annealed sample and the unannealed sample were similar, that of the 800 °C-annealed sample was extended to 11.6 (10.4 ns at 10 (300 K, which was more than two (four times those of the other samples. However, interestingly the spin relaxation time of the 800 °C-annealed sample was found to be similar to those of the other two samples. Particularly at room temperature, the spin relaxation times are 143 ps, 147 ps, and 111 ps for the 800 °C-annealed sample, 700 °C-annealed sample, and the unannealed sample, respectively.

  1. Reflectance improvement by thermal annealing of sputtered Ag/ZnO back reflectors in a-Si:H thin film silicon solar cells

    DEFF Research Database (Denmark)

    Haug, Franz-Josef; Söderström, Karin; Pahud, Céline

    2011-01-01

    Silver can be used as the back contact and reflector in thin film silicon solar cells. When deposited on textured substrates, silver films often exhibit reduced reflectance due to absorption losses by the excitation of surface plasmon resonances. We show that thermal annealing of the silver back...... reflector increases its reflectance drastically. The process is performed at low temperature (150°C) to allow the use of plastic sheets such as polyethylene naphthalate and increases the efficiency of single junction amorphous solar cells dramatically. We present the best result obtained on a flexible...

  2. Rapid thermal annealing effect on the spatial resistivity distribution of AZO thin films deposited by pulsed-direct-current sputtering for solar cells applications

    Energy Technology Data Exchange (ETDEWEB)

    Ayachi, Boubakeur, E-mail: boubakeur.ayachi@ed.univ-lille1.fr [Institute of Electronics, Microelectronics and Nanotechnology, Lille 1 University, Avenue Poincaré, UMR 8520, CS 60069, Villeneuve d’Ascq 59652 (France); Aviles, Thomas [CROSSLUX, Avenue Georges Vacher, ZI Rousset Peynier, Immeuble CCE, Rousset 13106 (France); Vilcot, Jean-Pierre [Institute of Electronics, Microelectronics and Nanotechnology, Lille 1 University, Avenue Poincaré, UMR 8520, CS 60069, Villeneuve d’Ascq 59652 (France); Sion, Cathy [Institute of Electronics, Microelectronics and Nanotechnology, Lille 1 University, Avenue Poincaré, UMR 8520, CS 60069, Villeneuve d’Ascq 59652 (France); Ecole Centrale Lille, Cité Scientifique – CS20048, Villeneuve d’Ascq 59651 (France)

    2016-03-15

    Graphical abstract: - Highlights: • High quality pulsed-DC sputtered AZO thin films were obtained after RTA treatment. • RTA for 30 s was sufficient to achieve uniform spatial resistivity distribution. • RTA for longer than 1 min showed a small increase in resistivity value. • Such improvement was attributed to grain boundaries passivation and doping activation. • In the framework of low cost solar cells development, RTA process would be helpful. - Abstract: Room temperature deposited aluminium-doped zinc oxide thin films on glass substrate, using pulsed-DC magnetron sputtering, have shown high optical transmittance and low electrical resistivity with high uniformity of its spatial distribution after they were exposed to a rapid thermal annealing process at 400 °C under N{sub 2}H{sub 2} atmosphere. It is particularly interesting to note that such an annealing process of AZO thin films for only 30 s was sufficient, on one hand to improve their optical transmittance from 73% to 86%, on the other hand to both decrease their resistivity from 1.7 × 10{sup −3} Ω cm to 5.1 × 10{sup −4} Ω cm and achieve the highest uniformity spatial distribution. To understand the mechanisms behind such improvements of the optoelectronic properties, electrical, optical, structural and morphological changes as a function of annealing time have been investigated by using hall measurement, UV–visible spectrometry, X-ray diffraction and scanning electron microscope imaging, respectively.

  3. X-ray diffraction and high resolution transmission electron microscopy characterization of intermetallics formed in Fe/Ti nanometer-scale multilayers during thermal annealing

    International Nuclear Information System (INIS)

    Wu, Z.L.; Peng, T.X.; Cao, B.S.; Lei, M.K.

    2009-01-01

    Intermetallics formation in the Fe/Ti nanometer-scale multilayers magnetron-sputtering deposited on Si(100) substrate during thermal annealing at 623-873 K was investigated by using small and wide angle X-ray diffraction and cross-sectional high-resolution transmission electron microscopy. The Fe/Ti nanometer-scale multilayers were constructed with bilayer thickness of 16.2 nm and the sublayer thickness ratio of 1:1. At the annealing temperature of 623 K, intermetallics FeTi were formed by nucleation at the triple joins of α-Fe(Ti)/α-Ti interface and α-Ti grain boundary with an orientational correlation of FeTi(110)//α-Ti(100) and FeTi[001]//α-Ti[001] to adjacent α-Ti grains. The lateral growth of intermetallics FeTi which is dependent on the diffusion path of Ti led to a coalescence into an intermetallic layer. With an increase in the annealing temperature, intermetallics Fe 2 Ti were formed between the intermetallics FeTi and the excess Fe due to the limitation of Fe and Ti atomic concentrations, resulting in the coexistence of intermetallics FeTi and Fe 2 Ti. It was found that the low energy interface as well as the dominant diffusion path constrained the nucleation and growth of intermetallics during interfacial reaction in the nanometer-scale metallic multilayers.

  4. Origin of a Raman scattering peak generated in single-walled carbon nanotubes by X-ray irradiation and subsequent thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Murakami, Toshiya; Matsuda, Mitsuaki; Itoh, Chihiro, E-mail: citoh@sys.wakayama-u.ac.jp [Department of Materials Science, Wakayama University, 930 Sakaedani, Wakayama 640-8510 (Japan); Kisoda, Kenji [Department of Physics, Wakayama University, 930 Sakaedani, Wakayama 640-8510 (Japan)

    2016-08-15

    We have found that a Raman scattering (RS) peak around 1870 cm{sup −1} was produced by the annealing of the X-ray irradiated film of single-walled carbon nanotubes (SWNTs) at 450 {sup o}C. The intensity of 1870-cm{sup −1} peak showed a maximum at the probe energy of 2.3 eV for the RS spectroscopy with various probe lasers. Both the peak position and the probe-energy dependence were almost identical to those of the one-dimensional carbon chains previously reported in multi-walled carbon nanotubes. Consequently, we concluded that the 1870-cm{sup −1} peak found in the present study is attributed to carbon chains. The formation of carbon chains by the annealing at temperature lower than 500 {sup o}C is firstly reported by the present study. The carbon chains would be formed by aggregation of the interstitial carbons, which are formed as a counterpart of carbon vacancies by X-ray irradiation diffused on SWNT walls. The result indicates that the combination of X-ray irradiation and subsequent thermal annealing is a feasible tool for generating new nanostructures in SWNT.

  5. Effect of In Situ Thermal Annealing on Structural, Optical, and Electrical Properties of CdS/CdTe Thin Film Solar Cells Fabricated by Pulsed Laser Deposition

    Directory of Open Access Journals (Sweden)

    Alaa Ayad Al-mebir

    2016-01-01

    Full Text Available An in situ thermal annealing process (iTAP has been introduced before the common ex situ cadmium chloride (CdCl2 annealing to improve crystal quality and morphology of the CdTe thin films after pulsed laser deposition of CdS/CdTe heterostructures. A strong correlation between the two annealing processes was observed, leading to a profound effect on the performance of CdS/CdTe thin film solar cells. Atomic force microscopy and Raman spectroscopy show that the iTAP in the optimal processing window produces considerable CdTe grain growth and improves the CdTe crystallinity, which results in significantly improved optoelectronic properties and quantum efficiency of the CdS/CdTe solar cells. A power conversion efficiency of up to 7.0% has been obtained on thin film CdS/CdTe solar cells of absorber thickness as small as 0.75 μm processed with the optimal iTAP at 450°C for 10–20 min. This result illustrates the importance of controlling microstructures of CdTe thin films and iTAP provides a viable approach to achieve such a control.

  6. Influence of CO annealing in metal-oxide-semiconductor capacitors with SiO2 films thermally grown on Si and on SiC

    Science.gov (United States)

    Pitthan, E.; dos Reis, R.; Corrêa, S. A.; Schmeisser, D.; Boudinov, H. I.; Stedile, F. C.

    2016-01-01

    Understanding the influence of SiC reaction with CO, a by-product of SiC thermal oxidation, is a key point to elucidate the origin of electrical defects in SiC metal-oxide-semiconductor (MOS) devices. In this work, the effects on electrical, structural, and chemical properties of SiO2/Si and SiO2/SiC structures submitted to CO annealing were investigated. It was observed that long annealing times resulted in the incorporation of carbon from CO in the Si substrate, followed by deterioration of the SiO2/Si interface, and its crystallization as SiC. Besides, this incorporated carbon remained in the Si surface (previous SiO2/Si region) after removal of the silicon dioxide film by HF etching. In the SiC case, an even more defective surface region was observed due to the CO interaction. All MOS capacitors formed using both semiconductor materials presented higher leakage current and generation of positive effective charge after CO annealings. Such results suggest that the negative fixed charge, typically observed in SiO2/SiC structures, is not originated from the interaction of the CO by-product, formed during SiC oxidation, with the SiO2/SiC interfacial region.

  7. Long duration blade loss simulations including thermal growths for dual-rotor gas turbine engine

    Science.gov (United States)

    Sun, Guangyoung; Palazzolo, Alan; Provenza, A.; Lawrence, C.; Carney, K.

    2008-09-01

    This paper presents an approach for blade loss simulation including thermal growth effects for a dual-rotor gas turbine engine supported on bearing and squeeze film damper. A nonlinear ball bearing model using the Hertzian formula predicts ball contact load and stress, while a simple thermal model estimates the thermal growths of bearing components during the blade loss event. The modal truncation augmentation method combined with a proposed staggered integration scheme is verified through simulation results as an efficient tool for analyzing a flexible dual-rotor gas turbine engine dynamics with the localized nonlinearities of the bearing and damper, with the thermal growths and with a flexible casing model. The new integration scheme with enhanced modeling capability reduces the computation time by a factor of 12, while providing a variety of solutions with acceptable accuracy for durations extending over several thermal time constants.

  8. Influence of Thermal Annealing and a Glass Coating on the Strength of Soda-Lime-Silicate Glass

    Science.gov (United States)

    2017-11-01

    glass used in a variety of military ballistic armor applications. A mixture of glass powder and isopropyl alcohol was sprayed onto the tin side of as...temperature at 3 °C/min. Plates that were scratched showed a noticeable strength increase following the annealing process; however, the addition of

  9. Structural, topographical and magnetic evolution of RF-sputtered Fe-Ni alloy based thin films with thermal annealing

    International Nuclear Information System (INIS)

    Lisha, R; Geetha, P; Anantharaman, M R; Hysen, T; Avasthi, D K; Ramanujan, R V

    2014-01-01

    Metglas 2826 MB having a nominal composition of Fe 40 Ni 38 Mo 4 B 18 is an excellent soft magnetic material and finds application in sensors and memory heads. However, the thin-film forms of Fe 40 Ni 38 Mo 4 B 18 are seldom studied, although they are important in micro-electro-mechanical systems/nano-electro-mechanical systems devices. The stoichiometry of the film plays a vital role in determining the structural and magnetic properties of Fe 40 Ni 38 Mo 4 B 18 thin films: retaining the composition in thin films is a challenge. Thin films of 52 nm thickness were fabricated by RF sputtering technique on silicon substrate from a target of nominal composition of Fe 40 Ni 38 Mo 4 B 18 . The films were annealed at temperatures of 400 °C and 600 °C. The micro-structural studies of films using glancing x-ray diffractometer (GXRD) and transmission electron microscope (TEM) revealed that pristine films are crystalline with (FeNiMo) 23 B 6 phase. Atomic force microscope (AFM) images were subjected to power spectral density analysis to understand the probable surface evolution mechanism during sputtering and annealing. X-ray photoelectron spectroscopy (XPS) was employed to determine the film composition. The sluggish growth of crystallites with annealing is attributed to the presence of molybdenum in the thin film. The observed changes in magnetic properties were correlated with annealing induced structural, compositional and morphological changes. (papers)

  10. Mesoscale Benchmark Demonstration Problem 1: Mesoscale Simulations of Intra-granular Fission Gas Bubbles in UO2 under Post-irradiation Thermal Annealing

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yulan; Hu, Shenyang Y.; Montgomery, Robert; Gao, Fei; Sun, Xin; Tonks, Michael; Biner, Bullent; Millet, Paul; Tikare, Veena; Radhakrishnan, Balasubramaniam; Andersson , David

    2012-04-11

    A study was conducted to evaluate the capabilities of different numerical methods used to represent microstructure behavior at the mesoscale for irradiated material using an idealized benchmark problem. The purpose of the mesoscale benchmark problem was to provide a common basis to assess several mesoscale methods with the objective of identifying the strengths and areas of improvement in the predictive modeling of microstructure evolution. In this work, mesoscale models (phase-field, Potts, and kinetic Monte Carlo) developed by PNNL, INL, SNL, and ORNL were used to calculate the evolution kinetics of intra-granular fission gas bubbles in UO2 fuel under post-irradiation thermal annealing conditions. The benchmark problem was constructed to include important microstructural evolution mechanisms on the kinetics of intra-granular fission gas bubble behavior such as the atomic diffusion of Xe atoms, U vacancies, and O vacancies, the effect of vacancy capture and emission from defects, and the elastic interaction of non-equilibrium gas bubbles. An idealized set of assumptions was imposed on the benchmark problem to simplify the mechanisms considered. The capability and numerical efficiency of different models are compared against selected experimental and simulation results. These comparisons find that the phase-field methods, by the nature of the free energy formulation, are able to represent a larger subset of the mechanisms influencing the intra-granular bubble growth and coarsening mechanisms in the idealized benchmark problem as compared to the Potts and kinetic Monte Carlo methods. It is recognized that the mesoscale benchmark problem as formulated does not specifically highlight the strengths of the discrete particle modeling used in the Potts and kinetic Monte Carlo methods. Future efforts are recommended to construct increasingly more complex mesoscale benchmark problems to further verify and validate the predictive capabilities of the mesoscale modeling

  11. Correlation of Etch Pits and Dislocations in As-grown and Thermal Cycle-Annealed HgCdTe(211) Films

    Science.gov (United States)

    Vaghayenegar, M.; Jacobs, R. N.; Benson, J. D.; Stoltz, A. J.; Almeida, L. A.; Smith, David J.

    2017-08-01

    This paper reports observations of the different types of etch pits and dislocations present in thick HgCdTe (211) layers grown by molecular beam epitaxy on CdTe/Si (211) composite substrates. Dislocation analysis for as-grown and thermal cycle-annealed samples has been carried out using bright-field transmission electron microscopy. Triangular pits present in as-grown material are associated with a mixture of Frank partials and perfect dislocations, while pits with fish-eye shapes have perfect dislocations with 1/2[0\\bar{1}1] Burgers vector. The dislocations beneath skew pits are more complex as they have two different crystallographic directions, and are associated with a mixture of Shockley partials and perfect dislocations. Dislocation analysis of samples after thermal cycle annealing (TCA) shows that the majority of dislocations under the etch pits are short segments of perfect dislocations with 1/2[0\\bar{1}1] Burgers vector while the remainder are Shockley partials. The absence of fish-eye shape pits in TCA samples suggests that they are associated with mobile dislocations that have reacted during annealing, causing the overall etch pit density to be reduced. Very large pits with a density ˜2×103 cm-2 are observed in as-grown and TCA samples. These defects thread from within the CdTe buffer layer into the upper regions of the HgCdTe layers. Their depth in as-grown material is so large that it is not possible to locate and identify the underlying defects.

  12. Microstructure and optical response optimization of Ge/Si quantum dots transformed from the sputtering-grown Ge thin film by manipulating the thermal annealing.

    Science.gov (United States)

    Shu, Qijiang; Wang, Rongfei; Yang, Jie; Zhang, Mingling; Zeng, Tianjian; Sun, Tao; Wang, Chong; Yang, Yu

    2018-03-02

    A series of zero-dimensional Ge/Si quantum dots (QDs) samples are fabricated by inducing the transformation from the two-dimensional Ge thin film, which is grown by the traditional direct current (DC) magnetron sputtering, via regulating the annealing process. The QD density increases sharply after the post rapid thermal annealing (PRTA). The observations of atomic force microscopy (AFM) and Raman spectroscopy suggest that the good morphology of Ge QDs results from an appropriate thermodynamics and kinetics surrounding shaped by the cooperative interaction of the Ge-Si lattice mismatch, the film's surface temperature, and the difference in thermal expansion coefficients between Ge and Si. The photoluminescence (PL) peaks of Ge QDs are detected in monolayer Ge QDs with ultrahigh density at 17 K. The Metal-Ge/Si QDs-Metal (MGM) photodetector fabricated from the ultrahigh-density QDs sample exhibits a relatively high current gain, absolute photoelectric responsivity, and internal quantum efficiency (IQE). Our results demonstrate that the high-quality Ge QDs with strong light absorption and quantum confinement effect can be realized by modulating DC magnetron sputtering and the PRTA process. This paves the way for realizing silicon-based optoelectronic devices with high performance by the traditional, relatively low-cost, and large-scale production nanomaterial fabricating method.

  13. Optimization of the contact resistance in the interface structure of n-type Al/a-SiC:H by thermal annealing for optoelectronics applications

    Energy Technology Data Exchange (ETDEWEB)

    Ambrosio, Roberto; Mireles, Jose Jr. [Technology and Engineering Institute, Ciudad Juarez University UACJ, Av. Del Charro 450N, 32310, Chihuahua (Mexico); Torres, Alfonso; Zuniga, Carlos; Moreno, Mario [National Institute for Astrophysics Optics and Electronics INAOE, Luis E. Erro 1, PO Box 51 and 216, 7200, Puebla (Mexico)

    2010-07-15

    The presented work meets the requirements for integration of amorphous silicon carbon films with silicon technology in order to obtain a complete optoelectronic system such as light emitting diodes and its electronic readout circuits. The key enabler for this integration scheme is the low temperature of deposition of a-SiC:H films and an ohmic behavior in the interface metal/a-SiC:H. In this work, the optimization of the interface Al/a-SiC:H films are performed by means of thermal annealing timing. The a-SiC:H films were deposited by enhanced chemical vapor deposition from CH{sub 4}/SiH{sub 4} and C{sub 2}H{sub 2}/SiH{sub 4} mixtures. The structural and optical properties of the deposited films are presented. An implantation phosphorous dose was used for doping before fabrication of patterned aluminum contacts. The implanted films were electrically characterized by the transfer length method (TLM) measuring a sheet resistance value as low as 171 M{omega}/square. The Schottky behavior was improved to ohmic behavior after several hours in thermal annealing treatments at 350 C, which allows to obtain a reasonable contact resistance values in the range from 8.6 to 26.8 k{omega}. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  14. Cu-Al alloy formation by thermal annealing of Cu/Al multilayer films deposited by cyclic metal organic chemical vapor deposition

    Science.gov (United States)

    Moon, Hock Key; Yoon, Jaehong; Kim, Hyungjun; Lee, Nae-Eung

    2013-05-01

    One of the most important issues in future Cu-based interconnects is to suppress the resistivity increase in the Cu interconnect line while decreasing the line width below 30 nm. For the purpose of mitigating the resistivity increase in the nanoscale Cu line, alloying Cu with traces of other elements is investigated. The formation of a Cu alloy layer using chemical vapor deposition or electroplating has been rarely studied because of the difficulty in forming Cu alloys with elements such as Al. In this work, Cu-Al alloy films were successfully formed after thermal annealing of Cu/Al multilayers deposited by cyclic metal-organic chemical vapor deposition (C-MOCVD). After the C-MOCVD of Cu/Al multilayers without gas phase reaction between the Cu and Al precursors in the reactor, thermal annealing was used to form Cu-Al alloy films with a small Al content fraction. The resistivity of the alloy films was dependent on the Al precursor delivery time and was lower than that of the aluminum-free Cu film. No presence of intermetallic compounds were detected in the alloy films by X-ray diffraction measurements and transmission electron spectroscopy.

  15. Correlating the silicon surface passivation to the nanostructure of low-temperature a-Si:H after rapid thermal annealing

    Science.gov (United States)

    Macco, Bart; Melskens, Jimmy; Podraza, Nikolas J.; Arts, Karsten; Pugh, Christopher; Thomas, Owain; Kessels, Wilhelmus M. M.

    2017-07-01

    Using an inductively coupled plasma, hydrogenated amorphous silicon (a-Si:H) films have been prepared at very low temperatures (advantage of the low-temperature approach is the facile suppression of undesired epitaxial growth. The correlation between the a-Si:H nanostructure and the activation of a-Si:H/c-Si interface passivation, upon annealing, has been studied in detail. This yields a structural model that qualitatively describes the different processes that take place in the a-Si:H films during annealing. The presented experimental findings and insights can prove to be useful in the further development of very thin a-Si:H passivation layers for use in silicon heterojunction solar cells.

  16. Semiconductor annealing

    International Nuclear Information System (INIS)

    Young, J.M.; Scovell, P.D.

    1982-01-01

    A process for annealing crystal damage in ion implanted semiconductor devices in which the device is rapidly heated to a temperature between 450 and 900 0 C and allowed to cool. It has been found that such heating of the device to these relatively low temperatures results in rapid annealing. In one application the device may be heated on a graphite element mounted between electrodes in an inert atmosphere in a chamber. (author)

  17. Pulsed Laser Annealing of Carbon

    Science.gov (United States)

    Abrahamson, Joseph P.

    This dissertation investigates laser heating of carbon materials. The carbon industry has been annealing carbon via traditional furnace heating since at least 1800, when Sir Humphry Davy produced an electric arc with carbon electrodes made from carbonized wood. Much knowledge has been accumulated about carbon since then and carbon materials have become instrumental both scientifically and technologically. However, to this day the kinetics of annealing are not known due to the slow heating and cooling rates of furnaces. Additionally, consensus has yet to be reached on the cause of nongraphitizability. Annealing trajectories with respect to time at temperature are observed from a commercial carbon black (R250), model graphitizable carbon (anthracene coke) and a model nongraphitizable carbon (sucrose char) via rapid laser heating. Materials were heated with 1064 nm and 10.6 im laser radiation from a Q-switched Nd:YAG laser and a continuous wave CO2 laser, respectively. A pulse generator was used reduce the CO2 laser pulse width and provide high temporal control. Time-temperature-histories with nanosecond temporal resolution and temperature reproducibility within tens of degrees Celsius were determined by spectrally resolving the laser induced incandescence signal and applying multiwavelength pyrometry. The Nd:YAG laser fluences include: 25, 50, 100, 200, 300, and 550 mJ/cm2. The maximum observed temperature ranged from 2,400 °C to the C2 sublimation temperature of 4,180 °C. The CO2 laser was used to collect a series of isothermal (1,200 and 2,600 °C) heat treatments versus time (100 milliseconds to 30 seconds). Laser heated samples are compared to furnace annealing at 1,200 and 2,600 °C for 1 hour. The material transformation trajectory of Nd:YAG laser heated carbon is different than traditional furnace heating. The traditional furnace annealing pathway is followed for CO2 laser heating as based upon equivalent end structures. The nanostructure of sucrose char

  18. Enhanced antiadhesive properties of chitosan/hyaluronic acid polyelectrolyte multilayers driven by thermal annealing: Low adherence for mammalian cells and selective decrease in adhesion for Gram-positive bacteria.

    Science.gov (United States)

    Muzzio, Nicolás E; Pasquale, Miguel A; Diamanti, Eleftheria; Gregurec, Danijela; Moro, Marta Martinez; Azzaroni, Omar; Moya, Sergio E

    2017-11-01

    The development of antifouling coatings with restricted cell and bacteria adherence is fundamental for many biomedical applications. A strategy for the fabrication of antifouling coatings based on the layer-by-layer assembly and thermal annealing is presented. Polyelectrolyte multilayers (PEMs) assembled from chitosan and hyaluronic acid were thermally annealed in an oven at 37°C for 72h. The effect of annealing on the PEM properties and topography was studied by atomic force microscopy, ζ-potential, circular dichroism and contact angle measurements. Cell adherence on PEMs before and after annealing was evaluated by measuring the cell spreading area and aspect ratio for the A549 epithelial, BHK kidney fibroblast, C2C12 myoblast and MC-3T3-E1 osteoblast cell lines. Chitosan/hyaluronic acid PEMs show a low cell adherence that decreases with the thermal annealing, as observed from the reduction in the average cell spreading area and more rounded cell morphology. The adhesion of S. aureus (Gram-positive) and E. coli (Gram-negative) bacteria strains was quantified by optical microscopy, counting the number of colony-forming units and measuring the light scattering of bacteria suspension after detachment from the PEM surface. A 20% decrease in bacteria adhesion was selectively observed in the S. aureus strain after annealing. The changes in mammalian cell and bacteria adhesion correlate with the changes in topography of the chitosan/hyaluronic PEMs from a rough fibrillar 3D structure to a smoother and planar surface after thermal annealing. Copyright © 2017. Published by Elsevier B.V.

  19. Thermal annealing of high dose radiation induced damage at room temperature in alkaline. Stored energy, thermoluminescence and coloration

    International Nuclear Information System (INIS)

    Delgado, L.

    1980-01-01

    The possible relation between stored energy, thermoluminescence and colour centre annealing in gamma and electron irradiated alkali halides is studied. Thermoluminescence occurs at temperature higher than the temperature at which the main stored energy peak appears. No stored energy release is detected in additively coloured KC1 samples. Plastic deformation and doping with Ca and Sr induce a stored energy spectrum different from the spectrum observed in pure and as cleaved samples, but the amount of stored energy does not change for a given irradiation dose.Capacity of alkali halides to store energy by irradiation increases as the cation size decreases. (Author) 51 refs

  20. Chemical bonding modifications of tetrahedral amorphous carbon and nitrogenated tetrahedral amorphous carbon films induced by rapid thermal annealing

    International Nuclear Information System (INIS)

    McCann, R.; Roy, S.S.; Papakonstantinou, P.; Bain, M.F.; Gamble, H.S.; McLaughlin, J.A.

    2005-01-01

    Tetrahedral amorphous carbon (ta-C) and nitrogenated tetrahedral amorphous carbon films (ta-CN x ), deposited by double bend off plane Filtered Vacuum Cathodic Arc were annealed up to 1000 deg. C in flowing argon for 2 min. Modifications on the chemical bonding structure of the rapidly annealed films, as a function of temperature, were investigated by NEXAFS, X-ray photoelectron and Raman spectroscopies. The interpretation of these spectra is discussed. The results demonstrate that the structure of undoped ta-C films prepared at floating potential with an arc current of 80 A remains stable up to 900 deg. C, whereas that of ta-CN x containing 12 at.% nitrogen is stable up to 700 deg. C. At higher temperatures, all the spectra indicated the predominant formation of graphitic carbon. Through NEXAFS studies, we clearly observed three π* resonance peaks at the ' N K edge structure. The origin of these three peaks is not well established in the literature. However our temperature-dependant study ascertained that the first peak originates from C=N bonds and the third peak originates from the incorporation of nitrogen into the graphite like domains

  1. Hydro-Thermal Scheduling by a Hybrid Evolutionary Programming—Simulated Annealing Method in a Large Power System

    Science.gov (United States)

    Nayak, Nimain Charan; Rajan, C. Christober Asir

    2010-10-01

    This Paper proposes a new hybrid algorithm for solving the Unit Commitment problem in Hydrothermal Power System using a hybrid Evolutionary Programming—Simulated Annealing method. The main objective of this project is to find the generation scheduling by committing the generating units such that the total operating cost can be minimized by satisfying both the forecasted load demand and various operating constraints of the generating units. It is a Global Optimization technique for solving Unit Commitment Problem, operates on a system, which is designed to encode each unit's operating schedule with regard to its minimum up/down time. In this method, the unit commitment schedule is coded as a string of symbols. An initial population of parent solutions is generated at random. Here the parents are obtained from a predefined set of solutions i.e. each and every solution is adjusted to meet the requirements. Then, random recommitment is carried out with respect to the unit's minimum down times. Simulated Annealing (SA) is a powerful optimization procedure that has been successfully applied to a number of combinatorial optimization problems. It avoids entrapment at local optimum by maintaining a short term memory of recently obtained solutions. Numerical results are shown comparing the cost solutions and computation time obtained by using the proposed hybrid method than conventional methods like Dynamic Programming, Lagrangian Relaxation.

  2. Influence of thermal annealing and radiation enhanced diffusion processes on surface plasmon resonance of gold implanted dielectric matrices

    Science.gov (United States)

    Devi, Ksh. Devarani; Ojha, Sunil; Singh, Fouran

    2018-03-01

    Gold nanoparticles (AuNPs) embedded in fused silica and sapphire dielectric matrices were synthesized by Au ion implantation. Systematic investigations were carried out to study the influence of implantation dose, post annealing temperature, swift heavy ion (SHI) irradiation and radiation enhanced diffusion (RED). Rutherford Backscattering Spectrometry (RBS) measurements were carried out to quantify concentration and depth profile of Au present in the host matrices. X-ray diffraction (XRD) was employed to characterize AuNPs formation. As-implanted and post-annealed films were irradiated using 100 MeV Ag ions to investigate the effect of electronic energy deposition on size and shape of NPs, which is estimated indirectly by the peak shape analysis of surface plasmon resonance (SPR). The effect of volume fraction of Au and their redistribution is also reported. A strong absorption in near infra red region is also noticed and understood by the formation of percolated NPs in dielectric matrices. It is quite clear from these results that the effect of RED assisted Oswald ripening is much more pronounced than the conventional Oswald ripening for the growth of NPs in the case of silica host matrices. However for sapphire matrices, it seems that growth of NPs already completed during implantation and it may be attributed to the high diffusivity of Au in sapphire matrices during implantation process.

  3. Thermal Annealing to Modulate the Shape Memory Behavior of a Biobased and Biocompatible Triblock Copolymer Scaffold in the Human Body Temperature Range.

    Science.gov (United States)

    Merlettini, Andrea; Gigli, Matteo; Ramella, Martina; Gualandi, Chiara; Soccio, Michelina; Boccafoschi, Francesca; Munari, Andrea; Lotti, Nadia; Focarete, Maria Letizia

    2017-08-14

    A biodegradable and biocompatible electrospun scaffold with shape memory behavior in the physiological temperature range is here presented. It was obtained starting from a specifically designed, biobased PLLA-based triblock copolymer, where the central block is poly(propylene azelate-co-propylene sebacate) (P(PAz60PSeb40)) random copolymer. Shape memory properties are determined by the contemporary presence of the low melting crystals of the P(PAz60PSeb40) block, acting as switching segment, and of the high melting crystal phase of PLLA blocks, acting as physical network. It is demonstrated that a straightforward annealing process applied to the crystal phase of the switching element gives the possibility to tune the shape recovery temperature from about 25 to 50 °C, without the need of varying the copolymer's chemical structure. The thermal annealing approach here presented can be thus considered a powerful strategy for "ad hoc" programming the same material for applications requiring different recovery temperatures. Fibroblast culture experiments demonstrated scaffold biocompatibility.

  4. Numerical Acoustic Models Including Viscous and Thermal losses: Review of Existing and New Methods

    DEFF Research Database (Denmark)

    Andersen, Peter Risby; Cutanda Henriquez, Vicente; Aage, Niels

    2017-01-01

    This work presents an updated overview of numerical methods including acoustic viscous and thermal losses. Numerical modelling of viscothermal losses has gradually become more important due to the general trend of making acoustic devices smaller. Not including viscothermal acoustic losses...... in such numerical computations will therefore lead to inaccurate or even wrong results. Both, Finite Element Method (FEM) and Boundary Element Method (BEM), formulations are available that incorporate these loss mechanisms. Including viscothermal losses in FEM computations can be computationally very demanding, due...... and BEM method including viscothermal dissipation are compared and investigated....

  5. Proceedings of the twenty-fourth water reactor safety information meeting. Volume 2: Reactor pressure vessel embrittlement and thermal annealing; Reactor vessel lower head integrity; Evaluation and projection of steam generator tube condition and integrity

    Energy Technology Data Exchange (ETDEWEB)

    Monteleone, S. [comp.] [Brookhaven National Lab., Upton, NY (United States)

    1997-02-01

    This three-volume report contains papers presented at the Twenty-Fourth Water Reactor Safety Information Meeting held at the Bethesda Marriott Hotel, Bethesda, Maryland, October 21--23, 1996. The papers are printed in the order of their presentation in each session and describe progress and results of programs in nuclear safety research conducted in this country and abroad. Foreign participation in the meeting included papers presented by researchers from Czech Republic, Finland, France, Japan, Norway, Russia and United Kingdom. This volume is divided into the following sections: reactor pressure vessel embrittlement and thermal annealing; reactor vessel lower head integrity; and evaluation and projection of steam generator tube condition and integrity. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database.

  6. Proceedings of the twenty-fourth water reactor safety information meeting. Volume 2: Reactor pressure vessel embrittlement and thermal annealing; Reactor vessel lower head integrity; Evaluation and projection of steam generator tube condition and integrity

    International Nuclear Information System (INIS)

    Monteleone, S.

    1997-02-01

    This three-volume report contains papers presented at the Twenty-Fourth Water Reactor Safety Information Meeting held at the Bethesda Marriott Hotel, Bethesda, Maryland, October 21--23, 1996. The papers are printed in the order of their presentation in each session and describe progress and results of programs in nuclear safety research conducted in this country and abroad. Foreign participation in the meeting included papers presented by researchers from Czech Republic, Finland, France, Japan, Norway, Russia and United Kingdom. This volume is divided into the following sections: reactor pressure vessel embrittlement and thermal annealing; reactor vessel lower head integrity; and evaluation and projection of steam generator tube condition and integrity. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database

  7. Combined analytical and phonon-tracking approaches to model thermal conductivity of etched and annealed nanoporous silicon

    Energy Technology Data Exchange (ETDEWEB)

    Randrianalisoa, Jaona [Centre de Thermique de Lyon, Villeurbanne (France); CETHIL UMR5008, CNRS, INSA-Lyon Universite Lyon 1, Villeurbanne (France); Baillis, Dominique [CETHIL UMR5008, CNRS, INSA-Lyon Universite Lyon 1, Villeurbanne (France)

    2009-10-15

    A combination of analytical and phonon-tracking approaches is proposed to predict thermal conductivity of porous nanostructured thick materials. The analytical approach derives the thermal conductivity as function of the intrinsic properties of the material and properties characterizing the phonon interaction with pore walls. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  8. Semiconductor annealing

    International Nuclear Information System (INIS)

    Young, J.M.; Scovell, P.D.

    1981-01-01

    A process for annealing crystal damage in ion implanted semiconductor devices is described in which the device is rapidly heated to a temperature between 450 and 600 0 C and allowed to cool. It has been found that such heating of the device to these relatively low temperatures results in rapid annealing. In one application the device may be heated on a graphite element mounted between electrodes in an inert atmosphere in a chamber. The process may be enhanced by the application of optical radiation from a Xenon lamp. (author)

  9. GaInAs Junction FET with InP buffer layer prepared by selective ion implantation of Be and rapid thermal annealing

    International Nuclear Information System (INIS)

    Selders, J.; Wachs, H.J.; Jurgensen, H.

    1986-01-01

    GaInAs JFETs were fabricated on VPE-grown GaInAs layers. The pn junctions have been realised with Be ion implantation and rapid thermal annealing. The devices show a high transconductance of 130 mS/mm and an electron saturation velocity of 1.8 x 10 7 cm/s. Channel mobilities measured at the complete device are as high as 6800 cm 2 /Vs. These excellent device properties are due to the use of an undoped InP buffer layer which avoids the diffusion of Fe from the substrate into the active layer. The data were supported by S-parameter measurements which gave a frequency limit of 20 GHz for gate dimensions of 1.6 by 200 μm 2 . (author)

  10. Solution-processed n-type fullerene field-effect transistors prepared using CVD-grown graphene electrodes: improving performance with thermal annealing.

    Science.gov (United States)

    Jeong, Yong Jin; Yun, Dong-Jin; Jang, Jaeyoung; Park, Seonuk; An, Tae Kyu; Kim, Lae Ho; Kim, Se Hyun; Park, Chan Eon

    2015-03-07

    Solution-processed organic field effect transistors (OFETs), which are amenable to facile large-area processing methods, have generated significant interest as key elements for use in all-organic electronic applications aimed at realizing low-cost, lightweight, and flexible devices. The low performance levels of n-type solution-processed bottom-contact OFETs unfortunately continue to pose a barrier to their commercialization. In this study, we introduced a combination of CVD-grown graphene source/drain (S/D) electrodes and fullerene (C60) in a solution-processable n-type semiconductor toward the fabrication of n-type bottom-contact OFETs. The C60 coating in the channel region was achieved by modifying the surface of the oxide gate dielectric layer with a phenyl group-terminated self-assembled monolayer (SAM). The graphene and phenyl group in the SAMs induced π-π interactions with C60, which facilitated the formation of a C60 coating. We also investigated the effects of thermal annealing on the reorganization properties and field-effect performances of the overlaying solution-processed C60 semiconductors. We found that thermal annealing of the C60 layer on the graphene surface improved the crystallinity of the face-centered cubic (fcc) phase structure, which improved the OFET performance and yielded mobilities of 0.055 cm(2) V(-1) s(-1). This approach enables the realization of solution-processed C60-based FETs using CVD-grown graphene S/D electrodes via inexpensive and solution-process techniques.

  11. Thermal annealing and UV irradiation effects on structure, morphology, photoluminescence and optical absorption spectra of EDTA-capped ZnS nanoparticles

    Science.gov (United States)

    Osman, M. A.; Othman, A. A.; El-Said, Waleed A.; Abd-Elrahim, A. G.; Abu-sehly, A. A.

    2016-02-01

    Monodispersed ZnS nanoparticles (NPs) were prepared by the chemical precipitation method. Thermally induced structural, morphological and optical changes have been investigated using x-ray diffraction, high-resolution transmission electron microscopy, optical absorption, photoluminescence (PL), and Fourier transform infrared and Raman spectroscopy. It was found that D increases with increasing annealing temperature (T a). The onset of the ZnS phase transition from cubic to hexagonal structure takes place at 400 °C, while cubic ZnS transforms into hexagonal ZnO via thermal oxidation in air at 600 °C. It is also noted that increasing T a results in the red shift of the optical band gap (E\\text{g}\\text{opt} ) and the thermal bleaching of exciton absorption. The PL spectrum of as-prepared ZnS nanopowder shows UV emission bands at 363 and 395 nm and blue and green emission at 438 and 515 nm, respectively. With increasing T a up to 500 °C, these bands were quenched and red-shifted. In addition, the UV irradiation effects on colloidal ZnS NPs were investigated. UV irradiation at a dose  ZnS NPs was discussed and an energy band diagram was proposed.

  12. Effects of thermal annealing on the optical, spectroscopic, and structural properties of tris (8-hydroxyquinolinate) gallium films grown on quartz substrates

    Energy Technology Data Exchange (ETDEWEB)

    Muhammad, Fahmi Fariq, E-mail: fahmi982@gmail.com [Low Dimensional Materials Research Center, Department of Physics, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia); Department of Physics, Faculty of Science and Engineering, University of Koya, Koya, Kurdistan Region (Iraq); Sulaiman, Khaulah [Low Dimensional Materials Research Center, Department of Physics, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia)

    2011-10-03

    Highlights: {yields} Achieving a broad absorption band for Gaq3 covering the whole UV and some parts of visible spectra. {yields} Increasing photoluminescence emission to five times stronger than that of pristine film. {yields} Conformational changes towards the formation of crystalline {alpha}-Gaq3 polymorph. {yields} Determination of glass transition temperature for Gaq3 (T{sub g} 182 deg. C) and Alq3 (T{sub g} = 173 deg. C). {yields} Improving and understanding the physical properties of Gaq3 film by means of thermal treatment. - Abstract: In this study we report the optical, spectroscopic, and structural properties of vacuum deposited tris (8-hydroxyquinolinate) gallium film upon thermal annealing in the temperature range from 85 deg. C to 255 deg. C under a flowing nitrogen gas for 10 min. The optical UV-vis-NIR and luminescence spectroscopy measurements were performed to estimate the absorption bands, optical energy gap (E{sub g}), and photoluminescence (PL) of the films. Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) techniques were used to probe the spectroscopic and structural nature of the films. We show that, by annealing the films from 85 deg. C to 235 deg. C, it is possible to achieve an enhanced absorption and increased photoluminescence to five times stronger than that of the pristine film. The PL quenching at 255 deg. C was attributed to the presence of plainer chains allow easy going for excitons to a long distance due to the crystalline region formation of {alpha}-Gaq3 polymorph. The reduction in E{sub g} and infrared absorption bands upon annealing were referred to the enhancement in {pi}-{pi} interchain interaction and conformational changes by re-arrangement of the Gaq3 quinolinate ligands, respectively. Stokes shift for the films were observed and calculated. From the differential scanning calorimetry, DSC measurements, higher glass transition temperature was observed for Gaq3 (T{sub g} = 182 deg. C) compared to

  13. Uncertainty-driven nuclear data evaluation including thermal (n,α) applied to 59Ni

    Science.gov (United States)

    Helgesson, P.; Sjöstrand, H.; Rochman, D.

    2017-11-01

    This paper presents a novel approach to the evaluation of nuclear data (ND), combining experimental data for thermal cross sections with resonance parameters and nuclear reaction modeling. The method involves sampling of various uncertain parameters, in particular uncertain components in experimental setups, and provides extensive covariance information, including consistent cross-channel correlations over the whole energy spectrum. The method is developed for, and applied to, 59Ni, but may be used as a whole, or in part, for other nuclides. 59Ni is particularly interesting since a substantial amount of 59Ni is produced in thermal nuclear reactors by neutron capture in 58Ni and since it has a non-threshold (n,α) cross section. Therefore, 59Ni gives a very important contribution to the helium production in stainless steel in a thermal reactor. However, current evaluated ND libraries contain old information for 59Ni, without any uncertainty information. The work includes a study of thermal cross section experiments and a novel combination of this experimental information, giving the full multivariate distribution of the thermal cross sections. In particular, the thermal (n,α) cross section is found to be 12.7 ± . 7 b. This is consistent with, but yet different from, current established values. Further, the distribution of thermal cross sections is combined with reported resonance parameters, and with TENDL-2015 data, to provide full random ENDF files; all of this is done in a novel way, keeping uncertainties and correlations in mind. The random files are also condensed into one single ENDF file with covariance information, which is now part of a beta version of JEFF 3.3. Finally, the random ENDF files have been processed and used in an MCNP model to study the helium production in stainless steel. The increase in the (n,α) rate due to 59Ni compared to fresh stainless steel is found to be a factor of 5.2 at a certain time in the reactor vessel, with a relative

  14. Empirical Validation of a Thermal Model of a Complex Roof Including Phase Change Materials

    Directory of Open Access Journals (Sweden)

    Stéphane Guichard

    2015-12-01

    Full Text Available This paper deals with the empirical validation of a building thermal model of a complex roof including a phase change material (PCM. A mathematical model dedicated to PCMs based on the heat apparent capacity method was implemented in a multi-zone building simulation code, the aim being to increase the understanding of the thermal behavior of the whole building with PCM technologies. In order to empirically validate the model, the methodology is based both on numerical and experimental studies. A parametric sensitivity analysis was performed and a set of parameters of the thermal model has been identified for optimization. The use of the generic optimization program called GenOpt® coupled to the building simulation code enabled to determine the set of adequate parameters. We first present the empirical validation methodology and main results of previous work. We then give an overview of GenOpt® and its coupling with the building simulation code. Finally, once the optimization results are obtained, comparisons of the thermal predictions with measurements are found to be acceptable and are presented.

  15. DOE's annealing prototype demonstration projects

    International Nuclear Information System (INIS)

    Warren, J.; Nakos, J.; Rochau, G.

    1997-01-01

    One of the challenges U.S. utilities face in addressing technical issues associated with the aging of nuclear power plants is the long-term effect of plant operation on reactor pressure vessels (RPVs). As a nuclear plant operates, its RPV is exposed to neutrons. For certain plants, this neutron exposure can cause embrittlement of some of the RPV welds which can shorten the useful life of the RPV. This RPV embrittlement issue has the potential to affect the continued operation of a number of operating U.S. pressurized water reactor (PWR) plants. However, RPV material properties affected by long-term irradiation are recoverable through a thermal annealing treatment of the RPV. Although a dozen Russian-designed RPVs and several U.S. military vessels have been successfully annealed, U.S. utilities have stated that a successful annealing demonstration of a U.S. RPV is a prerequisite for annealing a licensed U.S. nuclear power plant. In May 1995, the Department of Energy's Sandia National Laboratories awarded two cost-shared contracts to evaluate the feasibility of annealing U.S. licensed plants by conducting an anneal of an installed RPV using two different heating technologies. The contracts were awarded to the American Society of Mechanical Engineers (ASME) Center for Research and Technology Development (CRTD) and MPR Associates (MPR). The ASME team completed its annealing prototype demonstration in July 1996, using an indirect gas furnace at the uncompleted Public Service of Indiana's Marble Hill nuclear power plant. The MPR team's annealing prototype demonstration was scheduled to be completed in early 1997, using a direct heat electrical furnace at the uncompleted Consumers Power Company's nuclear power plant at Midland, Michigan. This paper describes the Department's annealing prototype demonstration goals and objectives; the tasks, deliverables, and results to date for each annealing prototype demonstration; and the remaining annealing technology challenges

  16. Economic Dispatch for Power System Included Wind and Solar Thermal Energy

    Directory of Open Access Journals (Sweden)

    Saoussen BRINI

    2009-07-01

    Full Text Available With the fast development of technologies of alternative energy, the electric power network can be composed of several renewable energy resources. The energy resources have various characteristics in terms of operational costs and reliability. In this study, the problem is the Economic Environmental Dispatching (EED of hybrid power system including wind and solar thermal energies. Renewable energy resources depend on the data of the climate such as the wind speed for wind energy, solar radiation and the temperature for solar thermal energy. In this article it proposes a methodology to solve this problem. The resolution takes account of the fuel costs and reducing of the emissions of the polluting gases. The resolution is done by the Strength Pareto Evolutionary Algorithm (SPEA method and the simulations have been made on an IEEE network test (30 nodes, 8 machines and 41 lines.

  17. Rapid flash annealing of thermally reactive copolymers in a roll-to-roll process for polymer solar cells

    DEFF Research Database (Denmark)

    Helgesen, Martin; Carlé, Jon Eggert; Andreasen, Birgitta

    2012-01-01

    Light induced thermocleaving of a thermally reactive copolymer based on dithienylthiazolo[5,4-d]thiazole (DTZ) and silolodithiophene (SDT) in contact with the heat sensitive substrate the heat sensitive substrate polyethyleneterphthalate (PET) was effectively demonstrated with the use of high...... intensity pulsed light, delivered by a commercial photonic sintering system. Thermally labile ester groups are positioned on the DTZ unit of the copolymer that can be eliminated thermally for enhanced photochemical stability and advantages in terms of processing (solubility/insolubility switching......). The photonic sintering system was successfully implemented in a full roll-to-roll process on flexible PET substrates and large-area polymer solar cell modules were prepared by solution processing of five layers under ambient conditions using the photonic sintering system for thermocleaving of the active layer...

  18. Enhanced propylene/propane separation by thermal annealing of an intrinsically microporous Hydroxyl-functionalized polyimide membrane

    KAUST Repository

    Swaidan, Ramy Jawdat

    2015-08-06

    Effective separation of propylene/propane is vital to the chemical industry where C3H6 is used as feedstock for a variety of important chemicals. The purity requirements are currently met with cryogenic distillation, which is an extremely energy-intensive process. Hybrid arrangements incorporating highly selective membranes (α>20) have been proposed to “debottleneck” the process and potentially improve the economics. Selective and permeable membranes can be obtained by the design of polymers of intrinsic microporosity (PIMs). In this work, a 250 °C annealed polyimide (PIM-6FDA-OH) membrane produced among the highest reported pure-gas C3H6/C3H8 selectivity of 30 for a solution-processable polymer to date. The high selectivity resulted from enhanced diffusivity selectivity due to the formation of inter-chain charge-transfer-complexes. Although there were some inevitable losses in selectivity under 50:50 mixed-gas feed conditions due to competitive sorption, relatively high selectivities were preserved due to enhanced plasticization resistance.

  19. Thermal annealing behavior of nano-size metal-oxide particles synthesized by ion implantation in Fe-Cr alloy

    Science.gov (United States)

    Zheng, C.; Gentils, A.; Ribis, J.; Borodin, V. A.; Descoins, M.; Mangelinck, D.; Dalle, F.; Arnal, B.; Delauche, L.

    2017-05-01

    Oxide dispersion strengthened (ODS) steels are promising structural materials for the next generation nuclear reactors, as well as fusion facilities. The detailed understanding of the mechanisms involved in the precipitation of nano-oxides during ODS steel production would strongly contribute to the improvement of the mechanical properties and the optimization of manufacturing of ODS steels, with a potentially strong economic impact for their industrialization. A useful tool for the experimental study of nano-oxide precipitation is ion implantation, a technique that is widely used to synthesize precipitate nanostructures in well-controlled conditions. Earlier, we have demonstrated the feasibility of synthesizing aluminum-oxide particles in the high purity Fe-10Cr alloy by consecutive implantation with Al and O ions at room temperature. This paper describes the effects of high-temperature annealing after the ion implantation stage on the development of the aluminum based oxide nanoparticle system. Using transmission electron microscopy and atom probe tomography experiments, we demonstrate that post-implantation heat treatment induces the growth of the nano-sized oxides in the implanted region and nucleation of new oxide precipitates behind the implantation zone as a result of the diffusion driven broadening of implant profiles. A tentative scenario for the development of metal-oxide nano-particles at both ion implantation and heat treatment stages is suggested based on the experimental observations.

  20. MHD SIMULATIONS OF CORONAL SUPRA-ARCADE DOWNFLOWS INCLUDING ANISOTROPIC THERMAL CONDUCTION

    Energy Technology Data Exchange (ETDEWEB)

    Zurbriggen, E.; Costa, A.; Schneiter, M.; Cécere, M. [Instituto de Investigaciones en Astronomía Teórica y Experimental (IATE), Córdoba (Argentina); Esquivel, A., E-mail: ezurbriggen@unc.edu.ar, E-mail: acosta@unc.edu.ar [Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México (Mexico)

    2016-11-20

    Coronal supra-arcade downflows (SADs) are observed as dark trails descending toward hot turbulent-fan-shaped regions. Due to the large temperature values and gradients in these fan regions, the thermal conduction (TC) should be very efficient. While several models have been proposed to explain the triggering and the evolution of SADs, none of these scenarios address a systematic consideration of TC. Thus, we accomplish this task numerically simulating the evolution of SADs within this framework. That is, SADs are conceived as voided (subdense) cavities formed by nonlinear waves triggered by downflowing bursty localized reconnection events in a perturbed hot fan. We generate a properly turbulent fan, obtained by a stirring force that permits control of the energy and vorticity input in the medium where SADs develop. We include anisotropic TC and consider plasma properties consistent with observations. Our aim is to study whether it is possible to prevent SADs from vanishing by thermal diffusion. We find that this will be the case, depending on the turbulence parameters, in particular if the magnetic field lines are able to envelope the voided cavities, thermally isolating them from the hot environment. Velocity shear perturbations that are able to generate instabilities of the Kelvin–Helmholtz type help to produce magnetic islands, extending the lifetime of SADs.

  1. Complete characterization by Raman spectroscopy of the structural properties of thin hydrogenated diamond-like carbon films exposed to rapid thermal annealing

    International Nuclear Information System (INIS)

    Rose, Franck; Wang, Na; Smith, Robert; Xiao, Qi-Fan; Dai, Qing; Marchon, Bruno; Inaba, Hiroshi; Matsumura, Toru; Saito, Yoko; Matsumoto, Hiroyuki; Mangolini, Filippo; Carpick, Robert W.

    2014-01-01

    We have demonstrated that multi-wavelength Raman and photoluminescence spectroscopies are sufficient to completely characterize the structural properties of ultra-thin hydrogenated diamond-like carbon (DLC:H) films subjected to rapid thermal annealing (RTA, 1 s up to 659 °C) and to resolve the structural differences between films grown by plasma-enhanced chemical vapor deposition, facing target sputtering and filtered cathodic vacuum arc with minute variations in values of mass density, hydrogen content, and sp 3 fraction. In order to distinguish unequivocally between films prepared with different density, thickness, and RTA treatment, a new method for analysis of Raman spectra was invented. This newly developed analysis method consisted of plotting the position of the Raman G band of carbon versus its full width at half maximum. Moreover, we studied the passivation of non-radiative recombination centers during RTA by performing measurements of the increase in photoluminescence in conjunction with the analysis of DLC:H networks simulated by molecular dynamics. The results show that dangling bond passivation is primarily a consequence of thermally-induced sp 2 clustering rather than hydrogen diffusion in the film.

  2. Preparation of Reduced Graphene Oxide:ZnO Hybrid Cathode Interlayer Using In Situ Thermal Reduction/Annealing for Interconnecting Nanostructure and Its Effect on Organic Solar Cell.

    Science.gov (United States)

    Zheng, Ding; Huang, Wei; Fan, Pu; Zheng, Yifan; Huang, Jiang; Yu, Junsheng

    2017-02-08

    A novel hybrid cathode interlayer (CIL) consisting of reduced graphene oxide and zinc oxide (ZnO) is realized in the inverted organic solar cells (OSCs). A dual-nozzle spray coating system and facile one-step in situ thermal reduction/annealing (ITR/ITA) method are introduced to precisely control the components of the CIL, assemble ZnO with graphene oxide, and reduce graphene oxide into in situ thermal reduced graphene oxide (IT-RGO), simultaneously. The ZnO:IT-RGO hybrid CIL shows high electric conductivity, interconnecting nanostructure, and matched energy level, which leads to a significant enhancement in the power conversion efficiency from 6.16% to 8.04% for PTB7:PC 71 BM and from 8.02% to 9.49% for PTB7-Th:PC 71 BM-based OSCs, respectively. This newly developed spray-coated ZnO:IT-RGO hybrid CIL based on one-step ITR/ITA treatment has the high potential to provide a facile pathway to fabricate the large-scale, fast fabrication, and high performance OSCs.

  3. Thermodynamic analysis of the effect of annealing on the thermal stability of a Cu–Al–Ni–Mn shape memory alloy

    Energy Technology Data Exchange (ETDEWEB)

    Mazzer, E.M., E-mail: ericmazzer@gmail.com [Postgraduate Program in Materials Science and Engineering, Federal University of São Carlos, São Carlos, SP (Brazil); Kiminami, C.S.; Bolfarini, C.; Cava, R.D.; Botta, W.J.; Gargarella, P. [Department of Materials Engineering, Federal University of São Carlos, São Carlos, SP (Brazil)

    2015-05-20

    Highlights: • We evaluated the effect of annealing on a Cu-based shape memory alloy. • Stabilization was clarified in terms of the chemical and non-chemical energies. • Stabilization was related to the shift of transformations temperatures. • Insights into the role of stabilization of phases by thermodynamics approach. - Abstract: Shape memory alloys (SMA) usually exhibit shifts in the transformation temperatures with increasing the number of thermal cycles. These shifts result from an increased stability of the martensite during cycling and have an important role in the functionality of the material. The structural reasons for these changes are not fully understood and are investigated here by a thermodynamic approach. The variation in the transformation temperatures and in the chemical and non-chemical energy terms of the total energy involved in the transformation of a Cu–Al–Ni–Mn SMA was studied. Powder of this alloy was produced by gas atomization with size in the range of 32–45 μm and subsequently heat-treated at 180 °C, 250 °C and 300 °C during different times. The as-cast and heat-treated samples were investigated by differential scanning calorimetry, X-ray diffraction and scanning and transmission electron microscopy. Only a single martensitic β′ phase was formed at room temperature. It was observed an increase in the austenitic start transformation temperature (A{sub s}) as well as in the austenitic finish transformation temperature (A{sub f}) with increasing the annealing time and temperature. The shift in the transformation temperatures to higher values is attributed to a decrease of the latent heat of transformation and non-chemical energy term, caused by changes in the structural order of the martensite. This study shows that the variation of the transformation temperatures is strongly linked to the total energy components, which can give important information about the stability of the alloy.

  4. Mechanics of damping for fiber composite laminates including hygro-thermal effects

    Science.gov (United States)

    Saravanos, D. A.; Chamis, Christos C.

    1989-01-01

    An integrated mechanics theory was developed for the modeling of composite damping from the micromechanics to the laminate level. Simplified, design oriented equations based on hysteretic damping are presented for on-axis plies, off-axis plies, and laminates including the effect of temperature, moisture, and interply hysteretic damping. The temperature rise within vibrating composite laminates resulting from strain energy dissipation is also modeled, and their coupled hygro-thermo-mechanical response is predicted. The method correlates well with reported damping measurements. Application examples illustrate the effect of various ply, laminate, and hygro-thermal parameters on the overall damping performance of composite laminates.

  5. Thermal histories of chondrules in solar nebula shocks, including the effect of molecular line cooling

    Science.gov (United States)

    Morris, Melissa A.

    Chondrules are millimeter-sized, silicate (mostly ferromagnesian) igneous spheres found within chondritic meteorites. They are some of the oldest materials in our Solar System, having formed within a few million years of its birth. Chondrules were melted at high temperature (over 1800 K), while they were free-floating objects in the early solar nebula. Their petrology and chemistry constrain their formation, especially their thermal histories. Chondrules provide some of the most powerful constraints on conditions in the solar nebula. Models in which chondrule precursors melted by passage through solar nebula shocks are very promising, and meet most constraints on chondrule formation in broad brush. However, these models have been lacking in some of the relevant physics. Previous shock models have used incorrect approximations to the input radiation boundary condition, and the opacity of solids has been treated simply. Most important, a proper treatment of cooling due to molecular line emission has not been included. In this thesis, the shock model is significantly improved in order to determine if it remains consistent with observational constraints. The appropriate boundary condition for the input radiation and the proper method for calculation of the opacity of solids are determined, and a complete treatment of molecular line cooling due to water is included. Previous estimates of the effect of line cooling predicted chondrule cooling rates in excess of 10,000 K per hour. However, once molecular line cooling due to water was incorporated into the full shock model, it was found that line cooling has a minimal effect on the thermal histories of gas and chondrules. This behavior is attributed mostly to the thermal buffering of the gas due to hydrogen dissociation and recombination, which tends to keep the gas temperature at approximately 2000 K until the column densities of water become optically thick to line emission. Chondrule cooling rates in the range of 10

  6. Origin of reverse annealing effect in hydrogen-implanted silicon

    Energy Technology Data Exchange (ETDEWEB)

    Di, Zengfeng [Los Alamos National Laboratory; Nastasi, Michael A [Los Alamos National Laboratory; Wang, Yongqiang [Los Alamos National Laboratory

    2009-01-01

    In contradiction to conventional damage annealing, thermally annealed H-implanted Si exhibits an increase in damage or reverse annealing behavior, whose mechanism has remained elusive. On the basis of quantitative high resolution transmission electron microscopy combined with channeling Rutherford backscattering analysis, we conclusively elucidate that the reverse annealing effect is due to the nucleation and growth of hydrogen-induce platelets. Platelets are responsible for an increase in the height and width the channeling damage peak following increased isochronal anneals.

  7. Control of O-H bonds at a-IGZO/SiO2 interface by long time thermal annealing for highly stable oxide TFT

    Directory of Open Access Journals (Sweden)

    Jae Kwon Jeon

    2017-12-01

    Full Text Available We report two-step annealing, high temperature and sequent low temperature, for amorphous indium-gallium-zinc-oxide (a-IGZO thin-film transistor (TFT to improve its stability and device performance. The annealing is carried out at 300 oC in N2 ambient for 1 h (1st step annealing and then at 250 oC in vacuum for 10 h (2nd step annealing. It is found that the threshold voltage (VTH changes from 0.4 V to -2.0 V by the 1st step annealing and to +0.6 V by 2nd step annealing. The mobility changes from 18 cm2V-1s-1 to 25 cm2V-1s-1 by 1st step and decreases to 20 cm2V-1s-1 by 2nd step annealing. The VTH shift by positive bias temperature stress (PBTS is 3.7 V for the as-prepared TFT, and 1.7 V for the 1st step annealed TFT, and 1.3 V for the 2nd step annealed TFT. The XPS (X-ray photoelectron spectroscopy depth analysis indicates that the reduction in O-H bonds at the top interface (SiO2/a-IGZO by 2nd step annealing appears, which is related to the positive VTH shift and smaller VTH shift by PBTS.

  8. Management of the Bohunice RPVs annealing procedures

    International Nuclear Information System (INIS)

    Repka, M.

    1994-01-01

    The program of annealing regeneration procedure of RPVs units 1 and 2 of NPP V-1 (EBO) realization in the year 1993, is the topic of this paper. In the paper the following steps are described in detail: the preparation works, the annealing procedure realization schedule and safety management: starting with zero conditions, assembling of annealing apparatus, annealing procedure, cooling down and disassembling procedure of annealing apparatus. At the end the programs of annealing of both RPVs including the dosimetry measurements are discussed and evaluated. (author). 3 figs

  9. Implementation aspects of the Boundary Element Method including viscous and thermal losses

    DEFF Research Database (Denmark)

    Cutanda Henriquez, Vicente; Juhl, Peter Møller

    2014-01-01

    The implementation of viscous and thermal losses using the Boundary Element Method (BEM) is based on the Kirchhoff’s dispersion relation and has been tested in previous work using analytical test cases and comparison with measurements. Numerical methods that can simulate sound fields in fluids in...... with mesh definition, geometrical singularities and treatment of closed cavities. These issues are specific of the BEM with losses. Using examples, some strategies are presented that can alleviate shortcomings and improve performance....... including losses are particularly interesting whenever small cavities and narrow passages are present, as is the case with many acoustic devices such as transducers and small audio appliances. The present paper describes current work aimed at improving the method by addressing some specific issues related...

  10. Effects of Mev Si Ions and Thermal Annealing on Thermoelectric and Optical Properties of SiO2/SiO2+Ge Multi-nanolayer thin Films

    Science.gov (United States)

    Budak, S.; Alim, M. A.; Bhattacharjee, S.; Muntele, C.

    Thermoelectric generator devices have been prepared from 200 alternating layers of SiO2/SiO2+Ge superlattice films using DC/RF magnetron sputtering. The 5 MeV Si ionsbombardmenthasbeen performed using the AAMU Pelletron ion beam accelerator to formquantum dots and / or quantum clusters in the multi-layer superlattice thin films to decrease the cross-plane thermal conductivity, increase the cross-plane Seebeck coefficient and increase the cross-plane electrical conductivity to increase the figure of merit, ZT. The fabricated devices have been annealed at the different temperatures to tailor the thermoelectric and optical properties of the superlattice thin film systems. While the temperature increased, the Seebeck coefficient continued to increase and reached the maximum value of -25 μV/K at the fluenceof 5x1013 ions/cm2. The decrease in resistivity has been seen between the fluence of 1x1013 ions/cm2 and 5x1013 ions/cm2. Transport properties like Hall coefficient, density and mobility did not change at all fluences. Impedance spectroscopy has been used to characterize the multi-junction thermoelectric devices. The loci obtained in the C*-plane for these data indicate non-Debye type relaxation displaying the presence of the depression parameter.

  11. Control of luminescence emitted by Cd{sub 1-x}Mn{sub x}S nanocrystals in a glass matrix: x concentration and thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Freitas Neto, Ernesto S; Dantas, Noelio O [Laboratorio de Novos Materiais Isolantes e Semicondutores (LNMIS), Instituto de Fisica, Universidade Federal de Uberlandia, CP 593, CEP 38400-902, Uberlandia, Minas Gerais (Brazil); Barbosa Neto, Newton M [Grupo de Espectroscopia de Materiais (GEM), Instituto de Fisica, Universidade Federal de Uberlandia, CP 593, CEP 38400-902, Uberlandia, Minas Gerais (Brazil); Guedes, Ilde [Departamento de Fisica, Universidade Federal do Ceara, Campus do Pici, CEP 60455-760, Fortaleza, Ceara (Brazil); Chen, Felipe, E-mail: ernestosfn@yahoo.com.br [Centro de Ciencias Naturais e Humanas, Universidade Federal do ABC, CEP 09210-170, Santo Andre, Sao Paulo (Brazil)

    2011-03-11

    Cd{sub 1-x}Mn{sub x}S nanocrystals (NCs) were successfully grown in a glass matrix and investigated by photoluminescence (PL), electron paramagnetic resonance (EPR) and magnetic force microscopy (MFM). We verified that the luminescent properties of these NCs can be controlled both by changing the x concentration and by thermal annealing of the samples. The EPR and PL data showed that the characteristic emission of Mn{sup 2+} ions ({sup 4}T{sub 1}-{sup 6}A{sub 1}) is only observed when this magnetic impurity is substitutionally incorporated in the Cd{sub 1-x}Mn{sub x}S NC core (site S{sub I}). Besides, it was observed that the emission ({sup 4}T{sub 1}-{sup 6}A{sub 1}) suppression, caused by the Mn{sup 2+} ion presence near the surface (site S{sub II}) of the Cd{sub 1-x}Mn{sub x}S NCs, is independent of the host material. The MFM images also confirmed the high quality of the Cd{sub 1-x}Mn{sub x}S NC samples, showing a uniform distribution of total magnetic moments in the nanoparticles.

  12. Fabrication of a Cu(InGaSe2 Thin Film Photovoltaic Absorber by Rapid Thermal Annealing of CuGa/In Precursors Coated with a Se Layer

    Directory of Open Access Journals (Sweden)

    Chun-Yao Hsu

    2013-01-01

    Full Text Available Cu(InGaSe2 (CIGS thin film absorbers are prepared using sputtering and selenization processes. The CuGa/In precursors are selenized during rapid thermal annealing (RTA, by the deposition of a Se layer on them. This work investigates the effect of the Cu content in precursors on the structural and electrical properties of the absorber. Using X-ray diffraction, field emission scanning electron microscopy, Raman spectroscopy, and Hall effect measurement, it is found that the CIGS thin films produced exhibit facetted grains and a single chalcopyrite phase with a preferred orientation along the (1 1 2 plane. A Cu-poor precursor with a Cu/( ratio of 0.75 demonstrates a higher resistance, due to an increase in the grain boundary scattering and a reduced carrier lifetime. A Cu-rich precursor with a Cu/( ratio of 1.15 exhibits an inappropriate second phase ( in the absorber. However, the precursor with a Cu/( ratio of 0.95 exhibits larger grains and lower resistance, which is suitable for its application to solar cells. The deposition of this precursor on Mo-coated soda lime glass substrate and further RTA causes the formation of a MoSe2 layer at the interface of the Mo and CIGS.

  13. Lattice Thermal Conductivity of Polyethylene Molecular Crystals from First-Principles Including Nuclear Quantum Effects.

    Science.gov (United States)

    Shulumba, Nina; Hellman, Olle; Minnich, Austin J

    2017-11-03

    Molecular crystals such as polyethylene are of intense interest as flexible thermal conductors, yet their intrinsic upper limits of thermal conductivity remain unknown. Here, we report a study of the vibrational properties and lattice thermal conductivity of a polyethylene molecular crystal using an ab initio approach that rigorously incorporates nuclear quantum motion and finite temperature effects. We obtain a thermal conductivity along the chain direction of around 160  W m^{-1} K^{-1} at room temperature, providing a firm upper bound for the thermal conductivity of this molecular crystal. Furthermore, we show that the inclusion of quantum nuclear effects significantly impacts the thermal conductivity by altering the phase space for three-phonon scattering. Our computational approach paves the way for ab initio studies and computational material discovery of molecular solids free of any adjustable parameters.

  14. The Effect of Thermal Annealing on the Optical Properties of a-SiC:H Films Produced by DC Sputtering Methods: I. Graphite Target Case.

    Directory of Open Access Journals (Sweden)

    Lusitra Munisa

    2003-04-01

    Full Text Available A study of the annealing effect on optical properties and disorder of hydrogenated amorphous silicon carbon (a-SiC:H films was undertaken. The films were prepared by sputtering technique using graphite target and silicon wafer in argon and hydrogen gas mixture, and then characterized by uv-vis (ultra violet-visible spectroscopy before and after annealing. Index of refraction n and absorption coefficient α of films have been determined from measurements of transmittance. The optical gap show small variation with annealing temperature, increasing with increasing annealing temperature up to 500 °C. An increase of annealing temperature leads to reduced film density and the amorphous network disorder. The experimental results are discussed in terms of deposition condition and compared to other experimental results.

  15. Loss and thermal model for power semiconductors including device rating information

    DEFF Research Database (Denmark)

    Ma, Ke; Bahman, Amir Sajjad; Beczkowski, Szymon

    2014-01-01

    pre-defined by experience with poor design flexibility. Consequently a more complete loss and thermal model is proposed in this paper, which takes into account not only the electrical loading but also the device rating as input variables. The quantified correlation between the power loss, thermal...

  16. Relationships among physical properties as indicators of high temperature deformation or post-shock thermal annealing in ordinary chondrites

    Energy Technology Data Exchange (ETDEWEB)

    Friedrich, Jon M.; Ruzicka, Alex; Macke, Robert J.; Thostenson, James O.; Rudolph, Rebecca A.; Rivers, Mark L.; Ebel, Denton S.

    2017-04-01

    Collisions and attendant shock compaction must have been important for the accretion and lithification of planetesimals, including the parent bodies of chondrites, but the conditions under which these occurred are not well constrained. A simple model for the compaction of chondrites predicts that shock intensity as recorded by shock stage should be related to porosity and grain fabric. To test this model, we studied sixteen ordinary chondrites of different groups (H, L, LL) using X-ray computed microtomography (μCT) to measure porosity and metal fabric, ideal gas pycnometry and 3D laser scanning to determine porosity, and optical microscopy (OM) to determine shock stage. These included a subsample of six chondrites previously studied using transmission electron microscopy (TEM) to characterize microstructures in olivine. Combining with previous data, results support the simple model in general, but not for chondrites with low shock-porosity-foliation (low-SPF chondrites). These include Kernouvé (H6), Portales Valley (H6/7), Butsura (H6), Park (L6), GRO 85209 (L6), Estacado (H6), MIL 99301 (LL6), Spade (H6), and Queen’s Mercy (H6), among others. The data for these meteorites are best explained by high ambient heat during or after shock. Low-SPF chondrites tend to have older 40Ar/39Ar ages (~4435–4526 Ma) than other, non-low-SPF type 6 chondrites in this study. We conclude that the H, L, and LL asteroids all were shock-compacted at an early stage while warm, with collisions occurring during metamorphic heating of the parent bodies. Results ultimately bear on whether chondrite parent bodies have internal structures more akin to a metamorphosed onion shell or metamorphosed rubble pile, and on the nature of accretion and lithification processes for planetesimals.

  17. Rapid thermally annealed plasma deposited SiNx:H thin films: Application to metal-insulator-semiconductor structures with Si, In0.53Ga0.47As, and InP

    International Nuclear Information System (INIS)

    Martil, I.; Prado, A. del; San Andres, E.; Gonzalez Diaz, G.; Martinez, F.L.

    2003-01-01

    We present in this article a comprehensive study of rapid thermal annealing (RTA) effects on the physical properties of SiN x :H thin films deposited by the electron cyclotron resonance plasma method. Films of different as-deposited compositions (defined in this article as the nitrogen to silicon ratio, x=N/Si) were analyzed: from Si-rich (x=0.97) to N-rich (x=1.6) films. The evolution of the composition, bonding configuration, and paramagnetic defects with the annealing temperature are explained by means of different network bond reactions that take place depending on the as-deposited film composition. All the analyzed films release hydrogen, while Si-rich and near-stoichiometric (x=1.43) ones also lose nitrogen upon annealing. These films were used to make Al/SiN x :H/semiconductor devices with Si, In 0.53 Ga 0.47 As, and InP. After RTA treatments, the electrical properties of the three different SiN x :H/semiconductor interfaces can be explained, noting the microstructural modifications that SiN x :H experiences upon annealing

  18. Modulation of the thermoluminescence glow curve of sol-gel synthesized SiO{sub 2} and Si O-2:Eu through thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Salas J, Ch. J.; Cruz V, C. [Universidad de Sonora, Departamento de Investigacion en Polimeros y Materiales, Apdo. Postal 130, 83000 Hermosillo, Sonora (Mexico); Bernal, R. [Universidad de Sonora, Departamento de Investigacion en Fisica, Apdo. Postal 5-088, 83190 Hermosillo, Sonora (Mexico); Castano, V. M., E-mail: salasjuarez@gimmunison.com [UNAM, Centro de Fisica Aplicada y Tecnologia Avanzada, Apdo. Postal 1-1010, 76000 Queretaro, Qro. (Mexico)

    2015-10-15

    Full text: Due to the increasing use of ionizing radiations, is necessary to monitor the radiation fields and exposure doses in facilities in which they are used. Different facilities or applications involve the use of different radiation and doses, and the sort of needed dosimetry also varies. Sometimes a conventional thermoluminescence (Tl) dosimetry satisfy the requirements since the record of the accumulated dose in a time interval is enough, but other cases could require for real-time measurement of a radiation field, being required a non-Tl dosimetric technique. On the other hand, different applications involve the use of different dose ranges, and so dosimeters with different sensitivities are needed. To solve the diverse needs of radiation detectors and dosimeters, a lot of phosphors materials has been characterized concerning their dosimetric capabilities. For medical application, biocompatible materials are desirable. In this work, we present experimental evidence that Sol-Gel synthesized SiO{sub 2} and SiO{sub 2}:Eu phosphors exhibit Tl glow curves composed by the superposition of several individual glow peaks each located at different temperature ranging from values below 100 up to temperatures greater than 400 degrees C, whose relative sensitivities can be modified by subjecting the phosphors to different thermal annealing. By modulating the relative intensities of the individual Tl peaks, glow curves with different shapes are obtained in such a way that SiO{sub 2} and SiO{sub 2}:Eu can be used to develop dosimeters useful for different dose ranges, and for both, conventional thermoluminescence dosimetry and non-thermoluminescence afterglow-based) dosimetry. (Author)

  19. Influence of the substrate and nitrogen amount on the microstructural and optical properties of thin r.f.-sputtered ZnO films treated by rapid thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Nicolescu, Madalina [Institute of Physical Chemistry, Romanian Academy, Spl. Independentei 202, 060021 Bucharest (Romania); Anastasescu, Mihai, E-mail: manastasescu@icf.ro [Institute of Physical Chemistry, Romanian Academy, Spl. Independentei 202, 060021 Bucharest (Romania); Preda, S.; Stroescu, H.; Stoica, M. [Institute of Physical Chemistry, Romanian Academy, Spl. Independentei 202, 060021 Bucharest (Romania); Teodorescu, V.S. [National Institute of Material Physics, 105 bis Atomistilor Street, 077125 Bucharest-Magurele (Romania); Aperathitis, E.; Kampylafka, V. [FORTH-IESL, Crete (Greece); Modreanu, M. [Tyndall National Institute, University College Cork, Cork (Ireland); Zaharescu, M.; Gartner, M. [Institute of Physical Chemistry, Romanian Academy, Spl. Independentei 202, 060021 Bucharest (Romania)

    2012-11-15

    Highlights: Black-Right-Pointing-Pointer ZnO:N films are crystallized in hexagonal wurtzite phase (XRD), (0 0 2) oriented. Black-Right-Pointing-Pointer The presence of the Nitrogen in the RTA films is confirmed by EDX and XPS. Black-Right-Pointing-Pointer All ZnO:N films are highly transparent (over 80%) in VIS to NIR spectral range. Black-Right-Pointing-Pointer The frequency of the phonon modes, E{sub 1}(TO) and A{sub 1}(LO), were obtained by IRSE. - Abstract: N-doped ZnO (ZnO:N) thin films, intended to be used as one of the layers in solar cell applications were deposited by r.f. sputtering, using ZnN target (99.9% purity), on silicon and fused silica substrates. In the gas flow composition, Ar was kept constant (50%) and the O{sub 2}/N{sub 2} ratio was varied as: 40%/10%, 25%/25% and 10%/40%. After deposition, rapid thermal annealing (RTA) at 400 and 550 Degree-Sign C for 1 min in N{sub 2} ambient has been performed. The RTA impact on the optical and microstructural properties of ZnO:N thin films have been investigated by X-ray diffraction (XRD), atomic force microscopy (AFM), transmission electron microscopy (TEM) coupled with selected area electron diffraction (SAED) and energy dispersive X-ray spectroscopy (EDX), UV-vis-NIR spectroscopy, UV-vis-NIR spectroscopic ellipsometry (SE) and infrared ellipsometry (IR-SE). The as-deposited (ad) ZnO:N films are polycrystalline with preferentially oriented columnar crystals. After RTA we found ZnO:N films with improved crystallinity and fewer boundary defects. We report optical constants of ZnO:N from UV to IR spectral range as well as the infrared active phononic modes.

  20. Irradiation, annealing, and reirradiation research in the ORNL heavy-section steel irradiation program

    International Nuclear Information System (INIS)

    Nanstad, R.K.; Iskander, S.K.; McCabe, D.E.; Sokolov, M.A.

    1997-01-01

    One of the options to mitigate the effects of irradiation on reactor pressure vessels (RPV) is to thermally anneal them to restore the toughness properties that have been degraded by neutron irradiation. This paper summarizes experimental results from work performed as part of the Heavy-Section Steel Irradiation (HSSI) Program managed by Oak Ridge National Laboratory (ORNL) for the U.S. Nuclear Regulatory Commission. The HSSI Program focuses on annealing and re-embrittlement response of materials which are representative of those in commercial RPVs and which are considered to be radiation-sensitive. Experimental studies include (1) the annealing of materials in the existing inventory of previously irradiated materials, (2) reirradiation of previously irradiated/annealed materials in a collaborative program with the University of California, Santa Barbara (UCSB), (3) irradiation/annealing/reirradiation of U.S. and Russian materials in a cooperative program with the Russian Research Center-Kurchatov Institute (RRC-KI), (4) the design and fabrication of an irradiation/anneal/reirradiation capsule and facility for operation at the University of Michigan Ford Reactor, (5) the investigation of potential for irradiation-and/or thermal-induced temper embrittlement in heat-affected zones (HAZs) of RPV steels due to phosphorous segregation at grain boundaries, and (6) investigation of the relationship between Charpy impact toughness and fracture toughness under all conditions of irradiation, annealing, and reirradiation

  1. The effect of low temperature thermal annealing on the magnetic properties of Heusler Ni–Mn–Sn melt-spun ribbons

    International Nuclear Information System (INIS)

    Llamazares, J.L. Sánchez; Quintana-Nedelcos, A.; Ríos-Jara, D.; Sánchez-Valdes, C.F.

    2016-01-01

    We report the effect of low temperature vacuum annealing (823 K; 550 °C) on the elemental chemical composition, structural phase transition temperatures, phase structure, and magnetic properties of Ni 50.6 Mn 36.3 Sn 13.1 as-solidified ribbons. Their elemental chemical composition, highly oriented columnar-like microstructure and single-phase character (L2 1 -type crystal structure for austenite) remain unchanged after this low temperature annealing. Annealed ribbons show a reduction of interatomic distances which lead to a small change in the characteristic phase transition temperatures (~3–6 K) but to a significant rise of ~73 and 63% in the saturation magnetization of the martensite and austenite phases, respectively, that can be strictly ascribed to the strengthening of ferromagnetic interactions due to the change in interatomic distances. - Highlights: • We study the effect of low temperature annealing on Ni 50.6 Mn 36.3 Sn 13.1 melt-spun ribbons. • Low temperature annealing preserves the crystal structure, composition and microstructure of the ribbons. • Low temperature annealing reduces the cell volume. • The strengthening of the ferromagnetic exchange interaction significant increases σ S .

  2. The effect of low temperature thermal annealing on the magnetic properties of Heusler Ni–Mn–Sn melt-spun ribbons

    Energy Technology Data Exchange (ETDEWEB)

    Llamazares, J.L. Sánchez, E-mail: jose.sanchez@ipicyt.edu.mx [Instituto Potosino de Investigación Científica y Tecnológica A.C., Camino a la Presa San José 2055, Col. Lomas 4a, San Luis Potosí S.L.P. 78216, México (Mexico); Quintana-Nedelcos, A. [Instituto Potosino de Investigación Científica y Tecnológica A.C., Camino a la Presa San José 2055, Col. Lomas 4a, San Luis Potosí S.L.P. 78216, México (Mexico); Marmara University, Department of Material and Metalurgy Eng., Kadıkoy 34777, Istanbul (Turkey); Ríos-Jara, D. [Instituto Potosino de Investigación Científica y Tecnológica A.C., Camino a la Presa San José 2055, Col. Lomas 4a, San Luis Potosí S.L.P. 78216, México (Mexico); Sánchez-Valdes, C.F. [Instituto Potosino de Investigación Científica y Tecnológica A.C., Camino a la Presa San José 2055, Col. Lomas 4a, San Luis Potosí S.L.P. 78216, México (Mexico); Centro de Nanociencias y Nanotecnología, Universidad Nacional Autónoma de México, AP 14, Ensenada 22860, Baja California, México (Mexico); and others

    2016-03-01

    We report the effect of low temperature vacuum annealing (823 K; 550 °C) on the elemental chemical composition, structural phase transition temperatures, phase structure, and magnetic properties of Ni{sub 50.6}Mn{sub 36.3}Sn{sub 13.1} as-solidified ribbons. Their elemental chemical composition, highly oriented columnar-like microstructure and single-phase character (L2{sub 1}-type crystal structure for austenite) remain unchanged after this low temperature annealing. Annealed ribbons show a reduction of interatomic distances which lead to a small change in the characteristic phase transition temperatures (~3–6 K) but to a significant rise of ~73 and 63% in the saturation magnetization of the martensite and austenite phases, respectively, that can be strictly ascribed to the strengthening of ferromagnetic interactions due to the change in interatomic distances. - Highlights: • We study the effect of low temperature annealing on Ni{sub 50.6}Mn{sub 36.3}Sn{sub 13.1} melt-spun ribbons. • Low temperature annealing preserves the crystal structure, composition and microstructure of the ribbons. • Low temperature annealing reduces the cell volume. • The strengthening of the ferromagnetic exchange interaction significant increases σ{sub S}.

  3. Morphological, thermal and annealed microhardness ...

    Indian Academy of Sciences (India)

    Unknown

    Chiellini Emo, Cinelli Patrizia, Elizabeth Grillo Fernandes, El-. Refaie S Kenawy and Andrea Lazzeri 2001 Biomacromole- cules 2 806. Deepak A M and Ashwini K 2000 J. Appl. Polym. Sci. 77 1782. Fraga Alicia N and Williams Roberto J J 1985 Polymer 26 113. Golden J H, Hamnalt B L and Hazella E A 1967 J. Appl. Polym.

  4. Effects of rapid thermal annealing on the electrical properties of the AlGaN/AlN/GaN heterostructure field-effect transistors with Ti/Al/Ni/Au gate electrodes

    International Nuclear Information System (INIS)

    Zhao, Jingtao; Lin, Zhaojun; Luan, Chongbiao; Zhou, Yang; Yang, Ming; Lv, Yuanjie; Feng, Zhihong

    2014-01-01

    In this study, we investigated the electrical properties of the AlGaN/AlN/GaN heterostructure field-effect transistors (HFETs) with Ti/Al/Ni/Au gate electrodes using the measured capacitance-voltage, current-voltage characteristics, and micro-Raman spectroscopy. We found that the uneven distribution of the strain caused by the Schottky metals was a major factor that generates the polarization Coulomb field scattering in AlGaN/AlN/GaN HFETs, and after appropriate rapid thermal annealing (RTA) processes, the polarization Coulomb field scattering was greatly weakened and the two-dimensional electron gas electron mobility was improved. We also found that the Schottky barrier height and the DC characteristics of the devices became better after appropriate RTA. Of course, the electrical performances mentioned above became deteriorated after excessive annealing.

  5. A Thermal Evolution Model of the Earth Including the Biosphere, Continental Growth and Mantle Hydration

    Science.gov (United States)

    Höning, D.; Spohn, T.

    2014-12-01

    By harvesting solar energy and converting it to chemical energy, photosynthetic life plays an important role in the energy budget of Earth [2]. This leads to alterations of chemical reservoirs eventually affecting the Earth's interior [4]. It further has been speculated [3] that the formation of continents may be a consequence of the evolution life. A steady state model [1] suggests that the Earth without its biosphere would evolve to a steady state with a smaller continent coverage and a dryer mantle than is observed today. We present a model including (i) parameterized thermal evolution, (ii) continental growth and destruction, and (iii) mantle water regassing and outgassing. The biosphere enhances the production rate of sediments which eventually are subducted. These sediments are assumed to (i) carry water to depth bound in stable mineral phases and (ii) have the potential to suppress shallow dewatering of the underlying sediments and crust due to their low permeability. We run a Monte Carlo simulation for various initial conditions and treat all those parameter combinations as success which result in the fraction of continental crust coverage observed for present day Earth. Finally, we simulate the evolution of an abiotic Earth using the same set of parameters but a reduced rate of continental weathering and erosion. Our results suggest that the origin and evolution of life could have stabilized the large continental surface area of the Earth and its wet mantle, leading to the relatively low mantle viscosity we observe at present. Without photosynthetic life on our planet, the Earth would be geodynamical less active due to a dryer mantle, and would have a smaller fraction of continental coverage than observed today. References[1] Höning, D., Hansen-Goos, H., Airo, A., Spohn, T., 2014. Biotic vs. abiotic Earth: A model for mantle hydration and continental coverage. Planetary and Space Science 98, 5-13. [2] Kleidon, A., 2010. Life, hierarchy, and the

  6. Fast thermal simulations and temperature optimization for hyperthermia treatment planning, including realistic 3D vessel networks

    NARCIS (Netherlands)

    Kok, H. P.; van den Berg, C. A. T.; Bel, A.; Crezee, J.

    2013-01-01

    Accurate thermal simulations in hyperthermia treatment planning require discrete modeling of large blood vessels. The very long computation time of the finite difference based DIscrete VAsculature model (DIVA) developed for this purpose is impractical for clinical applications. In this work, a fast

  7. Complete Loss and Thermal Model of Power Semiconductors Including Device Rating Information

    DEFF Research Database (Denmark)

    Ma, Ke; Bahman, Amir Sajjad; Beczkowski, Szymon

    2015-01-01

    models, only the electrical loadings are focused and treated as design variables, while the device rating is normally pre-defined by experience with limited design flexibility. Consequently, a more complete loss and thermal model is proposed in this paper, which takes into account not only the electrical...

  8. Numerical models of single- and double-negative metamaterials including viscous and thermal losses

    DEFF Research Database (Denmark)

    Cutanda Henriquez, Vicente; Sánchez-Dehesa, José

    2017-01-01

    detailed understanding on how viscous and thermal losses affect the setups at different frequencies. The modeling of a simpler single-negative metamaterial also broadens this overview. Both setups have been modeled with quadratic BEM meshes. Each sample, scaled at two different sizes, has been represented...

  9. Enthalpy relaxation and annealing effect in polystyrene.

    Science.gov (United States)

    Sakatsuji, Waki; Konishi, Takashi; Miyamoto, Yoshihisa

    2013-07-01

    The effects of thermal history on the enthalpy relaxation in polystyrene are studied by differential scanning calorimetry. The temperature dependence of the specific heat in the liquid and the glassy states, that of relaxation time, and the exponent of the Kohlrausch-Williams-Watts function are determined by measurements of the thermal response against sinusoidal temperature variation. A phenomenological model equation previously proposed to interpret the memory effect in the frozen state is applied to the enthalpy relaxation and the evolution of entropy under a given thermal history is calculated. The annealing below the glass transition temperature produces two effects on enthalpy relaxation: the decay of excess entropy with annealing time in the early stage of annealing and the increase in relaxation time due to physical aging in the later stage. The crossover of these effects is reflected in the variation of temperature of the maximum specific heat observed in the heating process after annealing and cooling.

  10. Influence of rapid thermal annealing effect on electrical and structural properties of Pd/Ru Schottky contacts to n-type GaN

    International Nuclear Information System (INIS)

    Reddy, N. Nanda Kumar; Reddy, V. Rajagopal; Choi, Chel-Jong

    2011-01-01

    Highlights: → Annealing effects on the electrical and structural properties of Ru/Pd/n-GaN SBDs are studied. → The optimum annealing temperature for Pd/Ru Schottky contact is 300 deg. C. → Increase in SBH upon annealing at 300 deg. C could be attributed to the formation of gallide phases. → The overall surface morphology of the Pd/Ru Schottky contacts on n-GaN is fairly smooth. - Abstract: Pd/Ru metallization scheme is fabricated on n-GaN as a Schottky contact, and the electrical and structural properties have been investigated as a function of annealing temperature by current-voltage (I-V), capacitance-voltage (C-V), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) measurements. As-deposited Ru/Pd/n-GaN contact yielded Schottky barrier height (SBH) of 0.67 eV (I-V) and 0.79 eV (C-V), respectively. Further, it is observed that the Schottky barrier height increases to 0.80 eV (I-V) and 0.96 eV (C-V) for the contact annealed at 300 deg. C. However, both I-V and C-V measurements indicate that the barrier height slightly decreased when the contacts are annealed at 400 deg. C and 500 deg. C. From the above observations, the optimum annealing temperature for Pd/Ru Schottky contact is 300 deg. C. Norde method is also employed to extract the barrier height of Pd/Ru Schottky contacts which are in good agreement with those obtained by the I-V technique. X-ray photoelectron spectroscopy results shows that the Ga 2p core-level shift towards the low-energy side for the contact annealed at 300 deg. C compared to the as-deposited contact. Based on the XPS and XRD results, the reason for the increase in SBH upon annealing at 300 deg. C could be attributed to the formation of gallide phases at the Ru/Pd/n-GaN interface vicinity. The AFM results showed that the overall surface morphology of the Pd/Ru Schottky contacts on n-GaN is fairly smooth. The above observations reveal that the Pd/Ru Schottky contact is attractive for high-temperature device

  11. An axisymmetric boundary element formulation of sound wave propagation in fluids including viscous and thermal losses

    DEFF Research Database (Denmark)

    Cutanda Henriquez, Vicente; Juhl, Peter Møller

    2013-01-01

    The formulation presented in this paper is based on the Boundary Element Method (BEM) and implements Kirchhoff’s decomposition into viscous, thermal and acoustic components, which can be treated independently everywhere in the domain except on the boundaries. The acoustic variables with losses ar...... as is the case with the existing Finite Element Method (FEM) implementations with losses. The suitability of this approach is demonstrated using an axisymmetrical BEM and two test cases where the numerical results are compared with analytical solutions.......The formulation presented in this paper is based on the Boundary Element Method (BEM) and implements Kirchhoff’s decomposition into viscous, thermal and acoustic components, which can be treated independently everywhere in the domain except on the boundaries. The acoustic variables with losses...

  12. Annealing of ion-implanted SiC by laser-pulse-exposure-generated shock-waves

    Science.gov (United States)

    Mulpuri, K. B.; Qadri, S. B.; Grun, J.; Manka, C. K.; Ridgway, M. C.

    2006-06-01

    Athermal annealing in phosphorus, boron, and aluminum/boron implanted 4H-SiC is explored by launching mechanical shock waves, induced by exposure to a laser pulse. Annealing is observed in a 3.2 mm outer diameter donut-shaped area surrounding the laser exposed spot. The minimum sheet-resistance within this area in phosphorus-implanted sample is close to the thermally annealed value of 400 Ω/□. Unlike thermal annealing, shock annealing did not cause any redistribution of the implant, including boron, a known transient enhanced diffuser in SiC. Optimization of parameters like laser power and/or pulse duration or investigation of an alternate mechanical shockwave launching method is required to achieve athermal annealing far away from the center of the exposed region and similar to that of the thermal annealed material. Results of this study might help in the manufacturing of silicon carbide high-power, high-temperature, and radiation hardened devices in the future.

  13. Modification of photosensing property of CdS–Bi{sub 2}S{sub 3} bi-layer by thermal annealing and swift heavy ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Shaikh, Shaheed U.; Siddiqui, Farha Y. [Thin Film and Nanotechnology Laboratory, Department of Physics (India); Department of Nanotechnology, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad 431004 (India); Singh, Fouran; Kulriya, Pawan K. [Inter University Accelerator Center, Aruna Asaf Ali Marg, New Delhi 110 067 (India); Phase, D.M. [UGC DAE Consortium for Scientific Research, Khandwa Road, Indore 452017 (India); Sharma, Ramphal, E-mail: ramphalsharma@yahoo.com [Thin Film and Nanotechnology Laboratory, Department of Physics (India); Department of Nanotechnology, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad 431004 (India)

    2016-02-01

    The CdS–Bi{sub 2}S{sub 3} bi-layer thin films have been deposited on Indium Tin Oxide (ITO) glass substrates at room temperature by Chemical Bath Deposition Technique (CBD) and bi-layer thin films were annealed in air atmosphere for 1 h at 250 {sup °}C. The air annealed sample was irradiated using Au{sup 9+} ions at the fluence 5 × 10{sup 11} ion/cm{sup 2} with 120 MeV energy. Effects of Swift Heavy Ion (SHI) irradiation on CdS–Bi{sub 2}S{sub 3} bi-layer thin films were studied. The results are explained on the basis annealing and high electronic excitation, using X-ray diffraction (XRD), Selective Electron Area Diffraction (SEAD), Atomic Force Microscopy (AFM), Raman Spectroscopy, UV spectroscopy and I–V characteristics. The photosensing property after illumination of visible light over the samples is studied. These as-deposited, annealed and irradiated bi-layer thin films are used to sense visible light at room temperature. - Graphical abstract: Schematic illustration of CdS–Bi{sub 2}S{sub 3} bi-layer thin film (a) As-deposited (b) Annealed (c) irradiated sample respectively (d) Model of bi-layer photosensor device (e) Graph of illumination intensity verses photosensitivity. - Highlights: • CdS–Bi{sub 2}S{sub 3} bi-layer thin film prepared at room temperature. • Irradiated using Au{sup 9+} ions at the fluence of 5 × 10{sup 11} ion/cm{sup 2} with 120 MeV energy. • Study of modification induced by irradiations. • Study of Photosensitivity after annealing and irradiation.

  14. Heat transfer behavior including thermal wake effects in forced air cooling of arrays of rectangular blocks

    International Nuclear Information System (INIS)

    Sridhar, S.; Faghri, M.; Lessmann, R.C.

    1990-01-01

    Experiments have been carried out to study thermal wake effects in arrays of rectangular blocks encountered in electronic equipment. Data were obtained for a series of channel heights and flow velocities. The temperature rise due to wake effects behind a single heated module was found to be fairly independent of the channel height and the position of the heated block, for a given approach velocity. The adiabatic temperature rise data for a module due to a heated element immediately upstream of it for different inter-module spacings were found to correlate well in terms of a new parameter called the surface packing density. This paper reports that it was reported by the authors in an earlier paper that both the adiabatic heat transfer coefficient nd pressure-drop data for regular in-line arrays correlated well in terms of a composite geometric parameter called the column packing density. These experiments have been extended to a higher Reynolds number. Empirical correlations are presented here for friction factor and Nusselt number in terms of the volume packing density, and for the thermal wake effects in terms of the surface packing density. Data from literature for arrays with widely different geometric parameters are shown to agree with these correlations

  15. Formation of oxygen related donors in step-annealed CZ–silicon

    Indian Academy of Sciences (India)

    The effect of step-annealing necessitated by the difficulties being faced in the long duration annealing treatments to be given to CZ–silicon has been studied. One pre-anneal of 10 h followed by annealing of 10 h causes a decrease in the absorption coefficient for carbon (c). Oxygen and carbon both accelerate thermal ...

  16. A Facile Approach to Tune the Electrical and Thermal Properties of Graphene Aerogels by Including Bulk MoS2

    Directory of Open Access Journals (Sweden)

    Feng Gong

    2017-12-01

    Full Text Available Graphene aerogels (GAs have attracted extensive interest in diverse fields, owing to their ultrahigh surface area, low density and decent electrical conductivity. However, the undesirable thermal conductivity of GAs may limit their applications in energy storage devices. Here, we report a facile hydrothermal method to modulate both the electrical and thermal properties of GAs by including bulk molybdenum disulfide (MoS2. It was found that MoS2 can help to reduce the size of graphene sheets and improve their dispersion, leading to the uniform porous micro-structure of GAs. The electrical measurement showed that the electrical conductivity of GAs could be decreased by 87% by adding 0.132 vol % of MoS2. On the contrary, the thermal conductivity of GAs could be increased by ~51% by including 0.2 vol % of MoS2. The quantitative investigation demonstrated that the effective medium theories (EMTs could be applied to predict the thermal conductivity of composite GAs. Our findings indicated that the electrical and thermal properties of GAs can be tuned for the applications in various fields.

  17. A Facile Approach to Tune the Electrical and Thermal Properties of Graphene Aerogels by Including Bulk MoS₂.

    Science.gov (United States)

    Gong, Feng; Liu, Xiongxiong; Yang, Yunlong; Xia, Dawei; Wang, Wenbin; Duong, Hai M; Papavassiliou, Dimitrios V; Xu, Ziqiang; Liao, Jiaxuan; Wu, Mengqiang

    2017-12-01

    Graphene aerogels (GAs) have attracted extensive interest in diverse fields, owing to their ultrahigh surface area, low density and decent electrical conductivity. However, the undesirable thermal conductivity of GAs may limit their applications in energy storage devices. Here, we report a facile hydrothermal method to modulate both the electrical and thermal properties of GAs by including bulk molybdenum disulfide (MoS₂). It was found that MoS₂ can help to reduce the size of graphene sheets and improve their dispersion, leading to the uniform porous micro-structure of GAs. The electrical measurement showed that the electrical conductivity of GAs could be decreased by 87% by adding 0.132 vol % of MoS₂. On the contrary, the thermal conductivity of GAs could be increased by ~51% by including 0.2 vol % of MoS₂. The quantitative investigation demonstrated that the effective medium theories (EMTs) could be applied to predict the thermal conductivity of composite GAs. Our findings indicated that the electrical and thermal properties of GAs can be tuned for the applications in various fields.

  18. Standard Guide for In-Service Annealing of Light-Water Moderated Nuclear Reactor Vessels

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2003-01-01

    1.1 This guide covers the general procedures to be considered for conducting an in-service thermal anneal of a light-water moderated nuclear reactor vessel and demonstrating the effectiveness of the procedure. The purpose of this in-service annealing (heat treatment) is to improve the mechanical properties, especially fracture toughness, of the reactor vessel materials previously degraded by neutron embrittlement. The improvement in mechanical properties generally is assessed using Charpy V-notch impact test results, or alternatively, fracture toughness test results or inferred toughness property changes from tensile, hardness, indentation, or other miniature specimen testing (1). 1.2 This guide is designed to accommodate the variable response of reactor-vessel materials in post-irradiation annealing at various temperatures and different time periods. Certain inherent limiting factors must be considered in developing an annealing procedure. These factors include system-design limitations; physical constrain...

  19. Numerical models of single- and double-negative metamaterials including viscous and thermal losses

    DEFF Research Database (Denmark)

    Cutanda Henriquez, Vicente; Sánchez-Dehesa, José

    2017-01-01

    Negative index acoustic metamaterials are artificial structures made of subwavelength units arranged in a lattice, whose effective acoustic parameters, bulk modulus and mass density, can be negative. In these materials, sound waves propagate inside the periodic structure, assumed rigid, showing...... extraordinary properties. We are interested in two particular cases: a double-negative metamaterial, where both parameters are negative at some frequencies, and a single-negative metamaterial with negative bulk modulus within a broader frequency band. In previous research involving the double-negative...... detailed understanding on how viscous and thermal losses affect the setups at different frequencies. The modeling of a simpler single-negative metamaterial also broadens this overview. Both setups have been modeled with quadratic BEM meshes. Each sample, scaled at two different sizes, has been represented...

  20. Application of Microextraction Techniques Including SPME and MESI to the Thermal Degradation of Polymers: A Review.

    Science.gov (United States)

    Kaykhaii, Massoud; Linford, Matthew R

    2017-03-04

    Here, we discuss the newly developed micro and solventless sample preparation techniques SPME (Solid Phase Microextraction) and MESI (Membrane Extraction with a Sorbent Interface) as applied to the qualitative and quantitative analysis of thermal oxidative degradation products of polymers and their stabilizers. The coupling of these systems to analytical instruments is also described. Our comprehensive literature search revealed that there is no previously published review article on this topic. It is shown that these extraction techniques are valuable sample preparation tools for identifying complex series of degradation products in polymers. In general, the number of products identified by traditional headspace (HS-GC-MS) is much lower than with SPME-GC-MS. MESI is particularly well suited for the detection of non-polar compounds, therefore number of products identified by this technique is not also to the same degree of SPME. Its main advantage, however, is its ability of (semi-) continuous monitoring, but it is more expensive and not yet commercialized.

  1. A graphic approach to include dissipative-like effects in reversible thermal cycles

    Science.gov (United States)

    Gonzalez-Ayala, Julian; Arias-Hernandez, Luis Antonio; Angulo-Brown, Fernando

    2017-05-01

    Since the decade of 1980's, a connection between a family of maximum-work reversible thermal cycles and maximum-power finite-time endoreversible cycles has been established. The endoreversible cycles produce entropy at their couplings with the external heat baths. Thus, this kind of cycles can be optimized under criteria of merit that involve entropy production terms. Meanwhile the relation between the concept of work and power is quite direct, apparently, the finite-time objective functions involving entropy production have not reversible counterparts. In the present paper we show that it is also possible to establish a connection between irreversible cycle models and reversible ones by means of the concept of "geometric dissipation", which has to do with the equivalent role of a deficit of areas between some reversible cycles and the Carnot cycle and actual dissipative terms in a Curzon-Ahlborn engine.

  2. BWR transient analysis using neutronic / thermal hydraulic coupled codes including uncertainty quantification

    International Nuclear Information System (INIS)

    Hartmann, C.; Sanchez, V.; Tietsch, W.; Stieglitz, R.

    2012-01-01

    The KIT is involved in the development and qualification of best estimate methodologies for BWR transient analysis in cooperation with industrial partners. The goal is to establish the most advanced thermal hydraulic system codes coupled with 3D reactor dynamic codes to be able to perform a more realistic evaluation of the BWR behavior under accidental conditions. For this purpose a computational chain based on the lattice code (SCALE6/GenPMAXS), the coupled neutronic/thermal hydraulic code (TRACE/PARCS) as well as a Monte Carlo based uncertainty and sensitivity package (SUSA) has been established and applied to different kind of transients of a Boiling Water Reactor (BWR). This paper will describe the multidimensional models of the plant elaborated for TRACE and PARCS to perform the investigations mentioned before. For the uncertainty quantification of the coupled code TRACE/PARCS and specifically to take into account the influence of the kinetics parameters in such studies, the PARCS code has been extended to facilitate the change of model parameters in such a way that the SUSA package can be used in connection with TRACE/PARCS for the U and S studies. This approach will be presented in detail. The results obtained for a rod drop transient with TRACE/PARCS using the SUSA-methodology showed clearly the importance of some kinetic parameters on the transient progression demonstrating that the coupling of a best-estimate coupled codes with uncertainty and sensitivity tools is very promising and of great importance for the safety assessment of nuclear reactors. (authors)

  3. Effects of thermal annealing in the post-reflow process on microstructure, tin crystallography, and impact reliability of Sn–Ag–Cu solder joints

    International Nuclear Information System (INIS)

    Chen, Wen-Lin; Yu, Chi-Yang; Ho, Cheng-Ying; Duh, Jenq-Gong

    2014-01-01

    This study aims to investigate the microstructure, β-Sn crystallography, micro-hardness and impact reliability of both Sn–3.0Ag–0.5Cu/Cu (SAC/Cu) and Sn–3.0Ag–0.5Cu/Ni (SAC/Ni) solder joints under various reflow processes. During the solidification step of the reflow process, solder joints were annealed at 210 °C for 50 s and 100 s, respectively. Network-type precipitations formed within the SAC/Cu joint, while dot-type precipitations distributed within the SAC/Ni joint. With the increase of annealing time, these precipitations grew larger; the interfacial intermetallic compounds (IMCs) became slightly thicker, and the hardness of solder alloys gradually decreased. Electron backscatter diffraction (EBSD) analysis indicates that the β-Sn grain structure depended on the distribution of precipitations. A high speed shear tester was used to evaluate the impact toughness of solder joints. Noteworthily, the short-time annealing can improve the impact reliability of solder joints. After annealing for 50 s, the average impact toughness of both SAC/Cu and SAC/Ni solder joints was enhanced, and the percentage of ductile fracture increased significantly. However, the growth of (Cu,Ni) 6 Sn 5 at the SAC/Ni interface degraded the impact toughness as the SAC/Ni joint was annealed for 100 s. The variation of impact toughness in SAC/Cu and SAC/Ni is correlated to the variation of microstructure and hardness in solder joints

  4. Impact of Annealing Thin Films In(OHxSy Growth By Solution Technique

    Directory of Open Access Journals (Sweden)

    Cliff Orori Mosiori

    2017-07-01

    Full Text Available Indium Hydroxy Sulphide has demonstrated abundance in resources, low prices, nontoxic characteristics, radiation resistance, high temperature resistance, and chemical stability, and therefore it has become an extremely important photoelectric, photovoltaic, and light sensing thin film material. Some treatment on this material include thermal annealing which is a process used for intrinsic stress liberation, structural improving, and surface roughness to control its electro-optical properties. In a qualitative way, annealing modifies surface morphology, intrinsic parameters, and electron mobility with temperature and time. In this work, an explanation on the surface modification of In(OHxSy thin films when subjected to an annealing process is discussed. Both electrical and optical effects caused by annealing were carried out and characterizations were performed at different annealing temperatures in nitrogen in the temperature range 373–573 K. Using optical measurements data and simulated data, Scout software was employed and the results showed that increasing annealing temperature causes a slight decrease in transmittance with a consequence of modifying the energy band gaps values between 2.79–3.32 eV. It was concluded that annealing influence optical transmittance and resistance of the film make the thin films potential for photovoltaic, and light sensing applications.

  5. NASTRAN thermal analyzer: Theory and application including a guide to modeling engineering problems, volume 2. [sample problem library guide

    Science.gov (United States)

    Jackson, C. E., Jr.

    1977-01-01

    A sample problem library containing 20 problems covering most facets of Nastran Thermal Analyzer modeling is presented. Areas discussed include radiative interchange, arbitrary nonlinear loads, transient temperature and steady-state structural plots, temperature-dependent conductivities, simulated multi-layer insulation, and constraint techniques. The use of the major control options and important DMAP alters is demonstrated.

  6. Transverse Crack Modeling and Validation in Rotor Systems Including Thermal Effects

    Directory of Open Access Journals (Sweden)

    N. Bachschmid

    2004-01-01

    Full Text Available In this article, a model is described that allows one to simulate the static behavior of a transversal crack in a horizontal rotor, under the action of the weight and other possible static loads and the dynamical behavior of the rotating cracked shaft. The crack “breaths,” i.e., the mechanism of opening and closing of the crack, is ruled by the stress acting on the cracked section due to the external loads; in a rotor the stress is time-depending with a period equal to the period of rotation, thus the crack “periodically breaths.” An original simplified model is described that allows cracks of different shape to be modeled and thermal stresses to be taken into account, since they may influence the opening and closing mechanism. The proposed method has been validated using two criteria. Firstly, the crack “breathing” mechanism, simulated with the model, has been compared with the results obtained by a nonlinear 3-D FEM calculation and a good agreement in the results has been observed. Secondly, the proposed model allows the development of the equivalent cracked beam. The results of this model are compared with those obtained by the above-mentioned 3-D FEM. There is a good agreement in the results, of this case as well.

  7. Transverse Crack Modeling and Validation in Rotor Systems, Including Thermal Effects

    Directory of Open Access Journals (Sweden)

    N. Bachschmid

    2003-01-01

    Full Text Available This article describes a model that allows the simulation of the static behavior of a transverse crack in a horizontal rotor under the action of weight and other possible static loads and the dynamic behavior of cracked rotating shaft. The crack breathes—that is, the mechanism of the crack's opening and closing is ruled by the stress on the cracked section exerted by the external loads. In a rotor, the stresses are time-dependent and have a period equal to the period of rotation; thus, the crack periodically breathes. An original, simplified model allows cracks of various shapes to be modeled and thermal stresses to be taken into account, as they may influence the opening and closing mechanism. The proposed method was validated by using two criteria. First the crack's breathing mechanism, simulated by the model, was compared with the results obtained by a nonlinear, threedimensional finite element model calculation, and a good agreement in the results was observed. Then the proposed model allowed the development of the equivalent cracked beam. The results of this model were compared with those obtained by the three-dimensional finite element model. Also in this case, there was a good agreement in the results.

  8. Development of Thermal Spraying and Coating Techniques by Using Thixotropic Slurries Including Metals and Ceramics Particles

    International Nuclear Information System (INIS)

    Kirihara, S; Tasaki, S; Itakura, Y

    2013-01-01

    Thermal nanoparticles coating and microlines patterning were newly developed as novel technologies to fabricate fine ceramics layers and geometrical intermetallics patterns for mechanical properties modulations of practical alloys substrates. Nanometer sized alumina particles were dispersed into acrylic liquid resins, and the obtained slurries were sputtered by using compressed air jet. The slurry mists could blow into the arc plasma with argon gas spraying. On stainless steels substrates, the fine surface layers with high wear resistance were formed. In cross sectional microstructures of the coated layers, micromater sized cracks or pores were not observed. Subsequently, pure aluminum particles were dispersed into photo solidified acrylic resins, and the slurry was spread on the stainless steel substrates by using a mechanical knife blade. On the substrates, microline patterns with self similar fractal structures were drawn and fixed by using scanning of an ultra violet laser beam. The patterned pure metal particles were heated by the argon arc plasma spray assisting, and the intermetallics or alloys phases with high hardness were created through reaction diffusions. Microstructures in the coated layers and the patterned lines were observed by using a scanning electron microscopy.

  9. Irradiation embrittlement and optimisation of annealing

    International Nuclear Information System (INIS)

    1993-01-01

    This conference is composed of 30 papers grouped in 6 sessions related to the following themes: neutron irradiation effects in pressure vessel steels and weldments used in PWR, WWER and BWR nuclear plants; results from surveillance programmes (irradiation induced damage and annealing processes); studies on the influence of variations in irradiation conditions and mechanisms, and modelling; mitigation of irradiation effects, especially through thermal annealing; mechanical test procedures and specimen size effects

  10. Effect of annealing temperature on the thermal stress and dislocation density of mc-Si ingot grown by DS process for solar cell application

    Science.gov (United States)

    Sanmugavel, S.; Srinivasan, M.; Aravinth, K.; Ramasamy, P.

    2018-04-01

    90% of the solar industries are using crystalline silicon. Cost wise the multi-crystalline silicon solar cells are better compared to mono crystalline silicon. But because of the presence of grain boundaries, dislocations and impurities, the efficiency of the multi-crystalline silicon solar cells is lower than that of mono crystalline silicon solar cells. By reducing the defect and dislocation we can achieve high conversion efficiency. The velocity of dislocation motion increases with stress. By annealing the grown ingot at proper temperature we can decrease the stress and dislocation. Our simulation results show that the value of stress and dislocation density is decreased by annealing the grown ingot at 1400K and the input parameters can be implemented in real system to grow a better mc-Si ingot for energy harvesting applications.

  11. In-situ thermal annealing of on-membrane silicon-on-insulator semiconductor-based devices after high gamma dose irradiation.

    Science.gov (United States)

    Amor, S; André, N; Kilchytska, V; Tounsi, F; Mezghani, B; Gérard, P; Ali, Z; Udrea, F; Flandre, D; Francis, L A

    2017-05-05

    In this paper, we investigate the recovery of some semiconductor-based components, such as N/P-type field-effect transistors (FETs) and a complementary metal-oxide-semiconductor (CMOS) inverter, after being exposed to a high total dose of gamma ray radiation. The employed method consists mainly of a rapid, low power and in situ annealing mitigation technique by silicon-on-insulator micro-hotplates. Due to the ionizing effect of the gamma irradiation, the threshold voltages showed an average shift of -580 mV for N-channel transistors, and -360 mV for P-MOSFETs. A 4 min double-cycle annealing of components with a heater temperature up to 465 °C, corresponding to a maximum power of 38 mW, ensured partial recovery but was not sufficient for full recovery. The degradation was completely recovered after the use of a built-in high temperature annealing process, up to 975 °C for 8 min corresponding to a maximum power of 112 mW, which restored the normal operating characteristics for all devices after their irradiation.

  12. The Evaporation and Survival of Cluster Galaxy Coronae. I. The Effectiveness of Isotropic Thermal Conduction Including Saturation

    Energy Technology Data Exchange (ETDEWEB)

    Vijayaraghavan, Rukmani; Sarazin, Craig, E-mail: rukmani@virginia.edu [Department of Astronomy, University of Virginia, 530 McCormick Rd., Charlottesville, VA 22904 (United States)

    2017-05-20

    We simulate the evolution of cluster galaxy hot interstellar medium (ISM) gas that is a result of the effects of ram pressure and thermal conduction in the intracluster medium (ICM). At the density and temperature of the ICM, the mean free paths of ICM electrons are comparable to the sizes of galaxies, therefore electrons can efficiently transport heat that is due to thermal conduction from the hot ICM to the cooler ISM. Galaxies consisting of dark matter halos and hot gas coronae are embedded in an ICM-like “wind tunnel” in our simulations. In this paper, we assume that thermal conduction is isotropic and include the effects of saturation. We find that as heat is transferred from the ICM to the ISM, the cooler denser ISM expands and evaporates. This process is significantly faster than gas loss due to ram pressure stripping; for our standard model galaxy, the evaporation time is 160 Myr, while the ram pressure stripping timescale is 2.5 Gyr. Thermal conduction also suppresses the formation of shear instabilities, and there are no stripped ISM tails since the ISM evaporates before tails can form. Observations of long-lived X-ray emitting coronae and ram pressure stripped X-ray tails in galaxies in group and cluster environments therefore require that thermal conduction is suppressed or offset by some additional physical process. The most likely process is anisotropic thermal conduction that is due to magnetic fields in the ISM and ICM, which we simulate and study in the next paper in this series.

  13. The Evaporation and Survival of Cluster Galaxy Coronae. I. The Effectiveness of Isotropic Thermal Conduction Including Saturation

    International Nuclear Information System (INIS)

    Vijayaraghavan, Rukmani; Sarazin, Craig

    2017-01-01

    We simulate the evolution of cluster galaxy hot interstellar medium (ISM) gas that is a result of the effects of ram pressure and thermal conduction in the intracluster medium (ICM). At the density and temperature of the ICM, the mean free paths of ICM electrons are comparable to the sizes of galaxies, therefore electrons can efficiently transport heat that is due to thermal conduction from the hot ICM to the cooler ISM. Galaxies consisting of dark matter halos and hot gas coronae are embedded in an ICM-like “wind tunnel” in our simulations. In this paper, we assume that thermal conduction is isotropic and include the effects of saturation. We find that as heat is transferred from the ICM to the ISM, the cooler denser ISM expands and evaporates. This process is significantly faster than gas loss due to ram pressure stripping; for our standard model galaxy, the evaporation time is 160 Myr, while the ram pressure stripping timescale is 2.5 Gyr. Thermal conduction also suppresses the formation of shear instabilities, and there are no stripped ISM tails since the ISM evaporates before tails can form. Observations of long-lived X-ray emitting coronae and ram pressure stripped X-ray tails in galaxies in group and cluster environments therefore require that thermal conduction is suppressed or offset by some additional physical process. The most likely process is anisotropic thermal conduction that is due to magnetic fields in the ISM and ICM, which we simulate and study in the next paper in this series.

  14. Thermal enhanced vapor extraction systems: Design, application and performance prediction including contaminant behavior

    International Nuclear Information System (INIS)

    Phelan, J.M.; Webb, S.W.

    1994-01-01

    Soil heating technologies have been proposed as a method to accelerate contaminant removal from subsurface soils. These methods include the use of hot air, steam, conductive heaters, in-situ resistive heating and in-situ radiofrequency heating (Buettner et.al., EPA, Dev et.al., Heath et.al.). Criteria for selection of a particular soil heating technology is a complex function of contaminant and soil properties, and efficiency in energy delivery and contaminant removal technologies. The work presented here seeks to expand the understanding of the interactions of subsurface water, contaminant, heat and vacuum extraction through model predictions and field data collection. Field demonstration will involve the combination of two soil heating technologies (resistive and dielectric) with a vacuum vapor extraction system and will occur during the summer of 1994

  15. Embrittlement recovery due to annealing of reactor pressure vessel steels

    International Nuclear Information System (INIS)

    Eason, E.D.; Wright, J.E.; Nelson, E.E.; Odette, G.R.; Mader, E.V.

    1995-01-01

    The irradiation embrittlement of nuclear reactor pressure vessels (RPV) can be reduced by thermal annealing at temperatures higher than the normal operating conditions. The objective of this work was to analyze the pertinent data and develop quantitative models for estimating the recovery in 30 ft-lb (41 J) Charpy transition temperature and Charpy upper shelf energy due to annealing. An analysis data base was developed, reviewed for completeness and accuracy, and documented as part of this work. Models were developed based on a combination of statistical techniques, including pattern recognition and transformation analysis, and the current understanding of the mechanisms governing embrittlement and recovery. The quality of models fitted in this project was evaluated by considering both the Charpy annealing data used for fitting and a surrogate hardness data base. This work demonstrates that microhardness recovery is i good surrogate for shift recovery and that there is a high level of consistency between he observed annealing trends and fundamental models of embrittlement and recovery processes

  16. Embrittlement recovery due to annealing of reactor pressure vessel steels

    International Nuclear Information System (INIS)

    Eason, E.D.; Wright, J.E.; Nelson, E.E.; Odette, G.R.; Mader, E.V.

    1998-01-01

    The irradiation embrittlement of nuclear reactor pressure vessels (RPV) can be reduced by thermal annealing at temperatures higher than the normal operating conditions. The objective of this work was to analyze the pertinent data and develop quantitative models for estimating the recovery in 41 J (30 ft-lb) Charpy transition temperature (TT) and Charpy upper shelf energy (USE) due to annealing. An analysis data base was developed, reviewed for completeness and accuracy, and documented as part of this work. Models were developed based on a combination of statistical techniques, including pattern recognition and transformation analysis, and the current understanding of the mechanisms governing embrittlement and recovery. The quality of models fitted in this project was evaluated by considering both the Charpy annealing data used for fitting and a surrogate hardness data base. This work demonstrates that microhardness recovery is a good surrogate for shift recovery and that there is a high level of consistency between the observed annealing trends and fundamental models of embrittlement and recovery processes. (orig.)

  17. Influence of thermal annealing on the morphology and structural properties of a conjugated polymer in blends with an organic acceptor material

    CSIR Research Space (South Africa)

    Motaung, DE

    2009-06-01

    Full Text Available by X-ray diffraction analysis. It was found that the crystallinity of the investigated films is drastically increased upon annealing. A decrease in grain sizes was observed for the blend which is due to a disordering of P3HT chains caused... with crystalline regions (circled in Fig. 2) which possess a spacing of ~ 0.8 ± 0.06 nm, corresponding to the (200) planes. Drees et al. [11] also reported a bright field TEM image of P3HT showing a large and extended disordered (amorphous) zone between...

  18. Effects of rapid thermal annealing on structural, chemical, and electrical characteristics of atomic-layer deposited lanthanum doped zirconium dioxide thin film on 4H-SiC substrate

    International Nuclear Information System (INIS)

    Lim, Way Foong; Quah, Hock Jin; Lu, Qifeng; Mu, Yifei; Ismail, Wan Azli Wan; Rahim, Bazura Abdul; Esa, Siti Rahmah; Kee, Yeh Yee; Zhao, Ce Zhou

    2016-01-01

    Graphical abstract: - Highlights: • Studies of RTA temperatures on La doped ZrO2 atomic layer deposited on 4HSiC. • Oxygen vacancies improved insulating and catalytic properties of La doped ZrO2. • 700 °C annealed sample showed the highest EB, k value, and sensitivity on O2. • La doped ZrO2 was proposed as a potential metal reactive oxide on 4H-SiC. - Abstract: Effects of rapid thermal annealing at different temperatures (700–900 °C) on structural, chemical, and electrical characteristics of lanthanum (La) doped zirconium oxide (ZrO 2 ) atomic layer deposited on 4H-SiC substrates have been investigated. Chemical composition depth profiling analysis using X-ray photoelectron spectroscopy (XPS) and cross-sectional studies using high resolution transmission electron microscopy equipped with energy dispersive X-ray spectroscopy line scan analysis were insufficient to justify the presence of La in the investigated samples. The minute amount of La present in the bulk oxide was confirmed by chemical depth profiles of time-of-flight secondary ion mass spectrometry. The presence of La in the ZrO 2 lattice led to the formation of oxygen vacancies, which was revealed through binding energy shift for XPS O 1s core level spectra of Zr−O. The highest amount of oxygen vacancies in the sample annealed at 700 °C has yielded the acquisition of the highest electric breakdown field (∼ 6.3 MV/cm) and dielectric constant value (k = 23) as well as the highest current–time (I–t) sensor response towards oxygen gas. The attainment of both the insulating and catalytic properties in the La doped ZrO 2 signified the potential of the doped ZrO 2 as a metal reactive oxide on 4H-SiC substrate.

  19. Influence of Co content and thermal annealing on structural, magnetic and magneto elastic properties of nanocrystalline Fe-Co-Nb-B alloys

    International Nuclear Information System (INIS)

    Khinchi, S.S.; Modak, S.S.; Kraus, L.; Svec, P.; Mazaleyrat, F.; Kane, S.N.

    2010-01-01

    Structural, magnetic and magneto elastic properties of the nanocrystalline Fe 84-x Co x Nb 7 B 9 (x=17, 25, 33) alloys have been studied using differential scanning calorimetry, X-ray diffraction, hysteresis and magnetostrictive measurements. Successive addition of Co reduces the stability of the alloys against the crystallization and also affects the structural, magnetic and magneto elastic properties. Observed magnetic behaviour suggests that in the coercive field exhibits for the increase of Co content in the alloy there is a changeover from third power dependence to sixth power dependence on grain size, ascribed to the presence of annealing induced anisotropies. Both experimentally obtained and estimated values of the saturation magnetostriction constant shows noticeable changes with increase in the annealing temperature and Co content in the parent alloy due to the increase of volume fraction of the nanograins, stresses and grain growth. Co content in nanocrystalline bcc Fe-Co phase ranges between 10-66%; whereas volume fraction of nanocrystalline phase and average grain diameter is in the range 15-70% and 8-20 nm, respectively.

  20. Structural properties of the formation of zinc-containing nanoparticles obtained by ion implantation in Si (001 and subsequent thermal annealing

    Directory of Open Access Journals (Sweden)

    Ksenia B. Eidelman

    2017-09-01

    We show that a damaged layer with a large concentration of radiation induced defects forms near the surface as a result of the implantation of Zn+ ions with an energy of 50 keV. In the as-implanted state, nanoparticles of metallic Zn with a size of about 25 nm form at a depth of 40 nm inside the damaged silicon layer. Subsequent annealing at 800 °C in a dry oxygen atmosphere leads to structural changes in the defect layer and the formation of Zn2SiO4 nanoparticles at a depth of 25 nm with an average size of 3 nm, as well as oxidation of the existing Zn particles to the Zn2SiO4 phase. The oxidation of the metallic Zn nanoparticles starts from the surface of the particles and leads to the formation of particles with a “core-shell” structure. Analysis of the phase composition of the silicon layer after two-stage implantation with O+ and Zn+ ions showed that Zn and Zn2SiO4 particles form in the as-implanted state. Subsequent annealing at 800 °C in a dry oxygen atmosphere leads to an increase in the particle size but does not change the phase composition of the near-surface layer. ZnO nanoparticles were not observed under these experimental conditions of ion beam synthesis.

  1. Implantation annealing in GaAs by incoherent light

    International Nuclear Information System (INIS)

    Davies, D.E.; Ryan, T.G.; Soda, K.J.; Comer, J.J.

    1983-01-01

    Implanted GaAs has been successfully activated through concentrating the output of quartz halogen lamps to anneal in times of the order of 1 sec. The resulting layers are not restricted by the reduced mobilities and thermal instabilities of laser annealed GaAs. Better activation can be obtained than with furnace annealing but this generally requires maximum temperatures >= 1050degC. (author)

  2. Features of an annealing-induced thermoluminescence peak in α-Al2O3:C,Mg

    Science.gov (United States)

    Kalita, J. M.; Chithambo, M. L.

    2017-08-01

    We report the thermoluminescence glow curves of beta irradiated single crystal α-Al2O3:C,Mg after annealing at 700 and 900 °C. A glow curve measured at 1 °C/s from samples irradiated to 1 Gy following annealing at 700 and 900 °C shows a high intensity peak at 163 °C and seven secondary peaks of weaker intensity at 43, 73, 100, 195, 280, 329 and 370 °C. Comparing the position of the peaks in the annealed samples with those in an un-annealed one, it is observed that the peak at 100 °C appears only after annealing at and above 700 °C. Kinetic analysis of this annealing-induced peak was carried out using the initial rise, whole glow peak, peak shape, curve fitting and variable heating rate methods. The order of kinetics of the peak was determined as first order using various methods including the Tm-Tstop technique and the dependence of Tm on irradiation dose. The activation energy of the peak is about 1.01 eV and the frequency factor of the order of 1012 s-1. The peak was found to be affected by thermal quenching in analysis based on change of peak intensity with heating rate. The activation energy of thermal quenching was evaluated as 1.06 ± 0.08 eV. We speculate that the annealing-induced peak is due to formation of a new electron trap after destruction of the F22+(2 Mg) centre when the sample is annealed at 700 °C. The annealing-induced peak fades with storage between irradiation and measurement. It was also concluded that electrons from traps corresponding to secondary peaks get re-trapped at the main electron trap.

  3. Training and knowledge development for use of software for safety analysis including ANSYS. Simulation of thermal-hydraulic benchmarks

    International Nuclear Information System (INIS)

    2016-01-01

    Comparison of both axial mean and rms velocities of the current analysis with the benchmark submissions and experimental results were consistent, showing that the LES transient model of ANSYS CFX is applicable to the problem of T-junction mixing and to predict the location of thermal fatigue from temperature differences. Study of ICEM CFD (Computational Fluid Dynamics) should be able to provide more tools for a finer hexahedral mesh of the T-junction leading to better results. A video of the flow in time obtained from CFD Post is included with this report to help with visualizing the results of the temperature variation along the pipe

  4. Nanocrystalline magnetic materials obtained by flash annealing

    Directory of Open Access Journals (Sweden)

    Murakami R.K.

    1999-01-01

    Full Text Available The aim of the present work was to produce enhanced-remanence nanocrystalline magnetic material by crystallizing amorphous or partially amorphous Pr4.5Fe77B18.5 alloys by the flash annealing process, also known as the dc-Joule heating process, and to determine the optimal conditions for obtaining good magnetic coupling between the magnetic phases present in this material. Ribbons of Pr4.5Fe77B18.5 were produced by melt spinning and then annealed for 10-30 s at temperatures 500 - 640 °C by passing current through the sample to develop the enhanced-remanence nanocrystalline magnetic material. These materials were studied by X-ray diffraction, differential thermal analysis and magnetic measurements. Coercivity increases of up to 15% were systematically observed in relation to furnace-annealed material. Two different samples were carefully examined: (i a sample annealed at 600 °C which showed the highest coercive field Hc and remanence ratio Mr/Ms and (ii a sample annealed at 520 °C which showed phase separation in the second quadrant demagnetization curve. Our results are in agreement with other studies which show that flash annealing improves the magnetic properties of some amorphous ferromagnetic ribbons.

  5. Constraints from Ly-α forests on non-thermal dark matter including resonantly-produced sterile neutrinos

    Science.gov (United States)

    Baur, Julien; Palanque-Delabrouille, Nathalie; Yèche, Christophe; Boyarsky, Alexey; Ruchayskiy, Oleg; Armengaud, Éric; Lesgourgues, Julien

    2017-12-01

    We use the large BOSS DR9 sample of quasar spectra to constrain two cases of non-thermal dark matter models: cold-plus-warm dark matter (C+WDM) where the warm component is a thermal relic, and sterile neutrinos resonantly produced in the presence of a lepton asymmetry (RPSN). We establish constraints on the thermal relic mass mx and its relative abundance Fwdm=Ωwdm/Ωdm using a suite of cosmological hydrodynamical simulations in 28 C+WDM configurations. We find that the 3σ bounds in the mx - Fwdm parameter space approximately follow Fwdm ~ 0.35 (keV/mx)-1.37 from BOSS data alone. We also establish constraints on sterile neutrino mass and mixing angle by further producing the non-linear flux power spectrum of 8 RPSN models, where the input linear power spectrum is computed directly from the particles distribution functions. We find values of lepton asymmetries for which sterile neutrinos as light as ~ 6.5 keV (resp. 3.5 keV) are consistent with BOSS data at the 2σ (resp. 3σ) level. These limits tighten by close to a factor of 2 for values of lepton asymmetries departing from those yielding the coolest distribution functions. Our Lyman-α forest bounds can be additionally strengthened if we include higher-resolution data from XQ-100, HIRES and MIKE that allow us to probe smaller scales. At these scales, the measured flux power spectrum exhibits a suppression that can be due to Doppler broadening, IGM pressure smoothing or free-streaming of WDM particles. In order to distinguish between these mechanisms, thermal history at redshifts z >= 5 should be determined. In the current work, we show that if one extrapolates temperatures from lower redshifts via broken power laws in T0 and γ, then our 3σ C+WDM {bounds strengthen to Fwdm ~ 0.20 (keV/mx)-1.37, and the lightest resonantly-produced sterile neutrinos consistent with our extended data set have masses of ~ 7.0 keV at the 3σ level. In particular, using dedicated hydrodynamical simulations, we show that} a

  6. Dynamics of open quantum systems by interpolation of von Neumann and classical master equations, and its application to quantum annealing

    Science.gov (United States)

    Kadowaki, Tadashi

    2018-02-01

    We propose a method to interpolate dynamics of von Neumann and classical master equations with an arbitrary mixing parameter to investigate the thermal effects in quantum dynamics. The two dynamics are mixed by intervening to continuously modify their solutions, thus coupling them indirectly instead of directly introducing a coupling term. This maintains the quantum system in a pure state even after the introduction of thermal effects and obtains not only a density matrix but also a state vector representation. Further, we demonstrate that the dynamics of a two-level system can be rewritten as a set of standard differential equations, resulting in quantum dynamics that includes thermal relaxation. These equations are equivalent to the optical Bloch equations at the weak coupling and asymptotic limits, implying that the dynamics cause thermal effects naturally. Numerical simulations of ferromagnetic and frustrated systems support this idea. Finally, we use this method to study thermal effects in quantum annealing, revealing nontrivial performance improvements for a spin glass model over a certain range of annealing time. This result may enable us to optimize the annealing time of real annealing machines.

  7. Efficiency of quantum vs. classical annealing in nonconvex learning problems.

    Science.gov (United States)

    Baldassi, Carlo; Zecchina, Riccardo

    2018-02-13

    Quantum annealers aim at solving nonconvex optimization problems by exploiting cooperative tunneling effects to escape local minima. The underlying idea consists of designing a classical energy function whose ground states are the sought optimal solutions of the original optimization problem and add a controllable quantum transverse field to generate tunneling processes. A key challenge is to identify classes of nonconvex optimization problems for which quantum annealing remains efficient while thermal annealing fails. We show that this happens for a wide class of problems which are central to machine learning. Their energy landscapes are dominated by local minima that cause exponential slowdown of classical thermal annealers while simulated quantum annealing converges efficiently to rare dense regions of optimal solutions. Copyright © 2018 the Author(s). Published by PNAS.

  8. The effects of thermal annealing on the structure and the electrical transport properties of ultrathin gadolinia-doped ceria films grown by pulsed laser deposition

    DEFF Research Database (Denmark)

    Rodrigo, Katarzyna Agnieszka; Heiroth, S.; Pryds, Nini

    2011-01-01

    show high density within the thickness probed in the X-ray reflectivity experiments. Thermally activated grain growth, density decrease, and film surface roughening, which may result in the formation of incoherent CGO10 islands by dewetting below a critical film thickness, are observed upon heat...... templates for the moderate temperature growth of thick solid electrolyte films with improved oxygen transport properties....

  9. Core–shell reconfiguration through thermal annealing in FexO/CoFe2O4 ordered 2D nanocrystal arrays

    NARCIS (Netherlands)

    Yalcin, A. O.; de Nijs, B.; Fan, Z.; Tichelaar, F.D.; Vanmaekelbergh, D.A.M.; van Blaaderen, A.; Vlugt, T.J.H.; van Huis, M.A.; Zandbergen, H.W.

    2014-01-01

    A great variety of single- and multi-component nanocrystals (NCs) can now be synthesized and integrated into nanocrystal superlattices. However, the thermal and temporal stability of these superstructures and their components can be a limiting factor for their application as functional devices. On

  10. Methods to include the influence of thermal bonds on the calculation of the energy performance of buildings and their influence on the heat demand for building heating

    Science.gov (United States)

    Valachova, D.; Zdrazilova, N.; Chudikova, B.

    2018-02-01

    The paper deals with the effect of thermal bonds on heat transmission of a building envelope. Then it deals with ways to include of thermal bonds in the calculation of heat loss through the building envelope and the calculation of energy efficiency of buildings. A solution of thermal bonds is very important, because it fundamentally influences the energy efficiency of the buildings. It is important to realize that building envelope comprises not only the peripheral surface structures but also thermal bonds in areas where building structures join.

  11. The effect of pre-annealing on the structural evolution and optical ...

    Indian Academy of Sciences (India)

    65

    Ag thin films of 5nm thickness were deposited on glass substrates by thermal evaporation. The films were divided into two sets out of which one set was not annealed and the other set was subjected to pre-annealing at 300oC for 2 hrs in air. The un-annealed and pre-annealed films were exposed to iodine vapours at room ...

  12. Thermal load histories for North American roof assembles using various cladding materials including wood-thermoplastic composite shingles

    Science.gov (United States)

    J. E. Winandy

    2006-01-01

    Since 1991, thermal load histories for various roof cladding types have been monitored in outdoor attic structures that simulate classic North American light-framed construction. In this paper, the 2005 thermal loads for wood-based composite roof sheathing, wood rafters, and attics under wood-plastic composite shingles are compared to common North American roof...

  13. The effect of thermal and vapor annealing treatments on the self-assembly of TiO2 /PS-b-PMMA nanocomposites generated via the sol-gel process

    International Nuclear Information System (INIS)

    Gutierrez, J; Tercjak, A; Garcia, I; Mondragon, I

    2009-01-01

    Polystyrene-block-poly(methyl methacrylate) (SMMA) block copolymer has been used as a structure-directing agent for generating TiO 2 /SMMA nanocomposites via the sol-gel process using a hydrophobic surfactant. The aim of the work has been focused on the preparation of well-defined nanostructured composites based on the self-assembling capability of the block copolymer using two different annealing methods: thermal- and solvent-induced microphase separation. The addition of different amounts of nanoparticles caused strong variations in the self-assembled morphology of the TiO 2 /SMMA nanocomposites with respect to the block copolymer, as observed by atomic force microscopy (AFM). To verify the confinement of the nanoparticles in the PMMA block 3D AFM images and corresponding AFM profiles have also been reported. UV light irradiation of the nanocomposite films provoked the removal of the organic matrix and consequently led to an array of TiO 2 nanoparticles on the substrate surface.

  14. Scalable effective-temperature reduction for quantum annealers via nested quantum annealing correction

    Science.gov (United States)

    Vinci, Walter; Lidar, Daniel A.

    2018-02-01

    Nested quantum annealing correction (NQAC) is an error-correcting scheme for quantum annealing that allows for the encoding of a logical qubit into an arbitrarily large number of physical qubits. The encoding replaces each logical qubit by a complete graph of degree C . The nesting level C represents the distance of the error-correcting code and controls the amount of protection against thermal and control errors. Theoretical mean-field analyses and empirical data obtained with a D-Wave Two quantum annealer (supporting up to 512 qubits) showed that NQAC has the potential to achieve a scalable effective-temperature reduction, Teff˜C-η , with 0 learning applications. Since we demonstrate that NQAC achieves error correction via a reduction of the effective-temperature of the quantum annealing device, our results address the problem of the "temperature scaling law for quantum annealers," which requires the temperature of quantum annealers to be reduced as problems of larger sizes are attempted to be solved.

  15. Laser-annealed GaP OHMIC contacts for high-temperature devices

    International Nuclear Information System (INIS)

    Eknoyan, O.; Van der Hoeven, W.; Richardson, T.; Porter, W.A.; Coquat, J.A.

    1980-01-01

    The results of successful Nd:YAG laser annealed ohmic contacts on n-type GaP are reported. Comparisons on identical laser and thermal annealed contacts on the same substrates are performed. Aging investigations are also studied. The results indicate that laser annealed contacts have far superior electrical characteristics, much better surface morphology and are substantially more stable with aging than the same but thermally alloyed ones

  16. Exploratory Study of Irradiation, Annealing, and Reirradiation Effects on American and Russian Reactor Pressure Vessel Steels

    Energy Technology Data Exchange (ETDEWEB)

    Chernobaeva, A.A., Kryukov, A.M., Nikolaev, Y.A., Korolev, Y.N. [Russian Research Centre Kurchatov Inst., Moscow (Russian Federation)], Sokolov, M.A., Nanstad, R.K. [Oak Ridge National Lab., TN (United States)

    1997-12-31

    One of the options to mitigate the effects of irradiation on reactor pressure vessels (RPVS) is to thermally anneal them to restore the toughness properties that have been degraded by neutron irradiation. even though a postirradiation anneal may be deemed successful, a critical aspect of continued RPV operation is the rate of embrittlement upon reirradiation. There are insufficient data available to allow for verification models of reirradiation embrittlement or for the development of a reliable predictive methodology. This is especially true in the case of fracture toughness data. Under the U.S.-Russia Joint Coordinating Committee for Civilian Nuclear Reactor Safety (JCCCNRS), Working Group 3 on Radiation Embrittlement, Structural Integrity, and Life Extension of Reactor Vessels and Supports agreed to conduct a comparative study of annealing and reirradiation effects on RPV steels. The working group agreed that each side would irradiate, anneal, reirradiate (if feasible), and test two materials of the other; so far, only charpy impact and tensile specimens have been included. Oak Ridge National Laboratory (ornl) conducted such a program (irradiation and annealing) with two weld metals representative of VVER-440 AND VVER-1000 RPVS, while the Russian Research Center-Kurchatov Institute (RRC-KI) conducted a program (irradiation,annealing, reirradiation, and reannealing) with Heavy-Section Steel Technology (HSST) program plate 02 and Heavy-Section Steel Irradiation (HSSI) program weld 73w. The results for each material from each laboratory are compared with those from the other laboratory. the ORNL experiments with the VVER welds included irradiation to about 1 x 10 (exp 19) N/SQ CM ({gt}1 MeV), while the RRC-KI experiments with the U.S. materials included irradiations from about 2 to 18 X 10 (exp 19) N/SQ CM ({gt}1 MeV).

  17. Influence of thermal annealing treatment in oxygen atmosphere on grain boundary chemistry and non-ohmic properties of SnO{sub 2}.MnO polycrystalline semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Orlandi, M.O. [Universidade Estadual Paulista, Departamento de Fisica e Quimica, P.O. Box 31, CEP 15385-000, Ilha Solteira-SP (Brazil); Bueno, P.R.; Longo, E. [Universidade Estadual Paulista, Instituto de Quimica, Departamento de Fisico-Quimica, C. Postal 355, 14800-900, Araraquara-SP (Brazil)

    2008-02-15

    The present work studied the influence of thermal treatment in oxygen rich atmosphere on heterogeneous junctions in Mn-doped SnO{sub 2} polycrystalline system presenting varistor behavior. The samples were prepared by conventional oxide mixture methodology, and were submitted to heat treatment in oxygen rich atmosphere at 900 C for 2 h. The samples were characterized by X-ray diffraction, scanning electron microscopy, dc and ac electrical measurements. The results showed that there is an evident relationship between the microstructure heterogeneity and non-ohmic electrical properties. It was found that for this SnO{sub 2}.MnO-based varistor system the heat treatment in oxygen rich atmosphere does not necessarily increase the varistors' properties, which was related to the decrease in the grain boundary resistance. The results are compared with Co-doped SnO{sub 2} varistors and ZnO based varistors. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  18. Metallic layer-by-layer photonic crystals for linearly-polarized thermal emission and thermophotovoltaic device including same

    Science.gov (United States)

    Lee, Jae-Hwang; Ho, Kai-Ming; Constant, Kristen P.

    2016-07-26

    Metallic thermal emitters consisting of two layers of differently structured nickel gratings on a homogeneous nickel layer are fabricated by soft lithography and studied for polarized thermal radiation. A thermal emitter in combination with a sub-wavelength grating shows a high extinction ratio, with a maximum value close to 5, in a wide mid-infrared range from 3.2 to 7.8 .mu.m, as well as high emissivity up to 0.65 at a wavelength of 3.7 .mu.m. All measurements show good agreement with theoretical predictions. Numerical simulations reveal that a high electric field exists within the localized air space surrounded by the gratings and the intensified electric-field is only observed for the polarizations perpendicular to the top sub-wavelength grating. This result suggests how the emissivity of a metal can be selectively enhanced at a certain range of wavelengths for a given polarization.

  19. Study of annealing effects in Al–Sb bilayer thin films

    Indian Academy of Sciences (India)

    Abstract. In this paper, we present preparation and characterization of Al–Sb bilayer thin films. Thin films of thicknesses, 3000/1000 Ц and 3000/1500 Е, were obtained by the thermal evaporation (resistive heating) method. Vacuum annealing and rapid thermal annealing methods were used to mix bilayer thin film structure.

  20. Study of annealing effects in Al–Sb bilayer thin films

    Indian Academy of Sciences (India)

    Keywords. AlSb; thin film; RBS; optical band gap. Abstract. In this paper, we present preparation and characterization of Al–Sb bilayer thin films. Thin films of thicknesses, 3000/1000 Å and 3000/1500 Å, were obtained by the thermal evaporation (resistive heating) method. Vacuum annealing and rapid thermal annealing ...

  1. A Numerical Model of an Acoustic Metamaterial Using the Boundary Element Method Including Viscous and Thermal Losses

    DEFF Research Database (Denmark)

    Cutanda Henriquez, Vicente; Andersen, Peter Risby; Jensen, Jakob Søndergaard

    2016-01-01

    In recent years, boundary element method (BEM) and finite element method (FEM) implementations of acoustics in fluids with viscous and thermal losses have been developed. They are based on the linearized Navier–Stokes equations with no flow. In this paper, such models with acoustic losses are app...

  2. Total heat loss coefficient of flat roof constructions with external insulation in tapered layers including the effects of thermal bridges

    DEFF Research Database (Denmark)

    Rose, Jørgen; Svendsen, Svend

    2005-01-01

    be quite tedious, and therefore a method to generate and optimize solutions has been developed and implemented in a program that also takes into account the effects of different types of thermal bridges, i.e. roof windows, insulation fasteners, roof/wall joints etc. This paper describes a new method...

  3. Anisotropic annealing of fission fragments in synthetic quartz

    CERN Document Server

    Sawamura, T; Narita, M

    1999-01-01

    A study on the thermal annealing behavior of fission fragments in synthetic quartz crystals was performed for application of synthetic quartz to track detectors under high temperature circumstances: x-, y-, and z-cut quartz plates were exposed to fission fragments from sup 2 sup 5 sup 2 Cf and were annealed up to 750 deg. C. It was found that track retention depended on the crystallographic structure: the annealing temperature, where the number of etched tracks was sharply reduced, was 550 deg. C for the x- and y-cut plates and 750 deg. C for z-cut plates. Track sizes decrease and disperse with reductions in the track retention.

  4. Effects of hydroxyl-functionalization and sub-Tg thermal annealing on high pressure pure- and mixed-gas CO2/CH4 separation by polyimide membranes based on 6FDA and triptycene-containing dianhydrides

    KAUST Repository

    Swaidan, Raja

    2015-02-01

    A sub-Tg thermally-annealed (250°C, 24h) ultra-microporous PIM-polyimide bearing a 9,10-diisopropyl-triptycene contortion center and hydroxyl-functionalized diamine (2,2-bis(3-amino-4-hydroxyphenyl)-hexafluoropropane, APAF) exhibited plasticization resistance up to 50bar for a 1:1 CO2/CH4 feed mixture, with a 9-fold higher CO2 permeability (30Barrer) and 2-fold increase in CO2/CH4 permselectivity (~50) over conventional dense cellulose acetate membranes at 10bar CO2 partial pressure. Interestingly, mixed-gas CO2/CH4 permselectivities were 10-20% higher than those evaluated under pure-gas conditions due to reduction of mixed-gas CH4 permeability by co-permeation of CO2. Gas transport, physisorption and fluorescence studies indicated a sieving pore-structure engaged in inter-chain charge transfer complexes (CTCs), similar to that of low-free-volume 6FDA-APAF polyimide. The isosteric heat of adsorption of CO2 as well as CO2/CH4 solubility selectivities varied negligibly upon replacement of OH with CH3 but CTC formation was hindered, CO2 sorption increased, CO2 permeability increased ~3-fold, CO2/CH4 permselectivity dropped to ~30 and CH4 mixed-gas co-permeation increased. These results suggest that hydroxyl-functionalization did not cause preferential polymer-gas interactions but primarily elicited diffusion-dominated changes owing to a tightened microstructure more resistant to CO2-induced dilations. Solution-processable hydroxyl-functionalized PIM-type polyimides provide a new platform of advanced materials that unites the high selectivities of low-free-volume polymers with the high permeabilities of PIM-type materials particularly for natural gas sweetening applications.

  5. The effect of thermal annealing on the adherence of Al2O3-films deposited by low-pressure, metal-organic, chemical-vapor deposition on AISI 304

    NARCIS (Netherlands)

    Haanappel, V.A.C.; Haanappel, V.A.C.; van de Vendel, D.; van Corbach, H.D.; Fransen, T.; Gellings, P.J.

    1995-01-01

    Thin alumina films, deposited at 280°C by low-pressure, metal-organic, chemical-vapor deposition on stainless steel, type AISI 304, were annealed at 0.17 kPa in a nitrogen atmosphere for 2,4, and 17 hr at 600, 700, and 800°C. The effect of the annealing process on the adhesion of the thin alumina

  6. Thermal damping effect due to a green barrier which includes Arundo donax as bioclimatic element in buildings

    Directory of Open Access Journals (Sweden)

    P. Rodríguez-Salinas

    2017-09-01

    Full Text Available Among the main environmental impacts of the operation of residential buildings are those due to greenhouse gases generation as a result of electric consumption of air conditioning systems. The use of vegetation systems in residential buildings represents an alternative to reduce this energy consumption. Green vegetation systems barriers are often used as protection against winds, but recently they are also being used as acoustic dampers. This work explores their use as thermal insulation systems for buildings. Specifically, we report the behavior of an Arundo donax green barrier as a bioclimatic element. The results are analyzed based on indoor and outdoor temperature measurement in prototype buildings, in function of the green barrier presence. Additionally Arundo donax transpiration under extreme environmental conditions was determined.

  7. A methodology to investigate the contribution of conduction and radiation heat transfer to the effective thermal conductivity of packed graphite pebble beds, including the wall effect

    Energy Technology Data Exchange (ETDEWEB)

    De Beer, M., E-mail: maritz.db@gmail.com [School of Mechanical and Nuclear Engineering, North-West University, Private Bag X6001, Potchefstroom 2520 (South Africa); Du Toit, C.G., E-mail: Jat.DuToit@nwu.ac.za [School of Mechanical and Nuclear Engineering, North-West University, Private Bag X6001, Potchefstroom 2520 (South Africa); Rousseau, P.G., E-mail: pieter.rousseau@uct.ac.za [Department of Mechanical Engineering, University of Cape Town, Private Bag X3, Rondebosch 7701 (South Africa)

    2017-04-01

    Highlights: • The radiation and conduction components of the effective thermal conductivity are separated. • Near-wall effects have a notable influence on the effective thermal conductivity. • Effective thermal conductivity is a function of the macro temperature gradient. • The effective thermal conductivity profile shows a characteristic trend. • The trend is a result of the interplay between conduction and radiation. - Abstract: The effective thermal conductivity represents the overall heat transfer characteristics of a packed bed of spheres and must be considered in the analysis and design of pebble bed gas-cooled reactors. During depressurized loss of forced cooling conditions the dominant heat transfer mechanisms for the passive removal of decay heat are radiation and conduction. Predicting the value of the effective thermal conductivity is complex since it inter alia depends on the temperature level and temperature gradient through the bed, as well as the pebble packing structure. The effect of the altered packing structure in the wall region must therefore also be considered. Being able to separate the contributions of radiation and conduction allows a better understanding of the underlying phenomena and the characteristics of the resultant effective thermal conductivity. This paper introduces a purpose-designed test facility and accompanying methodology that combines physical measurements with Computational Fluid Dynamics (CFD) simulations to separate the contributions of radiation and conduction heat transfer, including the wall effects. Preliminary results obtained with the methodology offer important insights into the trends observed in the experimental results and provide a better understanding of the interplay between the underlying heat transfer phenomena.

  8. Improving Nanofiber Membrane Characteristics and Membrane Distillation Performance of Heat-Pressed Membranes via Annealing Post-Treatment

    Directory of Open Access Journals (Sweden)

    Minwei Yao

    2017-01-01

    Full Text Available Electrospun membranes are gaining interest for use in membrane distillation (MD due to their high porosity and interconnected pore structure; however, they are still susceptible to wetting during MD operation because of their relatively low liquid entry pressure (LEP. In this study, post-treatment had been applied to improve the LEP, as well as its permeation and salt rejection efficiency. The post-treatment included two continuous procedures: heat-pressing and annealing. In this study, annealing was applied on the membranes that had been heat-pressed. It was found that annealing improved the MD performance as the average flux reached 35 L/m2·h or LMH (>10% improvement of the ones without annealing while still maintaining 99.99% salt rejection. Further tests on LEP, contact angle, and pore size distribution explain the improvement due to annealing well. Fourier transform infrared spectroscopy and X-ray diffraction analyses of the membranes showed that there was an increase in the crystallinity of the polyvinylidene fluoride-co-hexafluoropropylene (PVDF-HFP membrane; also, peaks indicating the α phase of polyvinylidene fluoride (PVDF became noticeable after annealing, indicating some β and amorphous states of polymer were converted into the α phase. The changes were favorable for membrane distillation as the non-polar α phase of PVDF reduces the dipolar attraction force between the membrane and water molecules, and the increase in crystallinity would result in higher thermal stability. The present results indicate the positive effect of the heat-press followed by an annealing post-treatment on the membrane characteristics and MD performance.

  9. Grain coarsening mechanism of Cu thin films by rapid annealing

    International Nuclear Information System (INIS)

    Sasajima, Yasushi; Kageyama, Junpei; Khoo, Khyoupin; Onuki, Jin

    2010-01-01

    Cu thin films have been produced by an electroplating method using nominal 9N anode and nominal 6N CuSO 4 .5H 2 O electrolyte. Film samples were heat-treated by two procedures: conventional isothermal annealing in hydrogen atmosphere (abbreviated as H 2 annealing) and rapid thermal annealing with an infrared lamp (abbreviated as RTA). After heat treatment, the average grain diameters and the grain orientation distributions were examined by electron backscattering pattern analysis. The RTA samples (400 o C for 5 min) have a larger average grain diameter, more uniform grain distribution and higher ratio of (111) orientation than H 2 annealed samples (400 o C for 30 min). This means that RTA can produce films with coarser and more uniformly distributed grains than H 2 annealing within a short time, i.e. only a few minutes. To clarify the grain coarsening mechanism, grain growth by RTA was simulated using the phase field method. The simulated grain diameter reaches its maximum at a heating rate which is the same order as that in the actual RTA experiment. The maximum grain diameter is larger than that obtained by H 2 annealing with the same annealing time at the isothermal stage as in RTA. The distribution of the misorientation was analyzed which led to a proposed grain growth model for the RTA method.

  10. Fuel cell integral bundle assembly including ceramic open end seal and vertical and horizontal thermal expansion control

    Science.gov (United States)

    Zafred, Paolo R [Murrysville, PA; Gillett, James E [Greensburg, PA

    2012-04-24

    A plurality of integral bundle assemblies contain a top portion with an inlet fuel plenum and a bottom portion containing a base support, the base supports a dense, ceramic air exhaust manifold having four supporting legs, the manifold is below and connects to air feed tubes located in a recuperator zone, the air feed tubes passing into the center of inverted, tubular, elongated, hollow electrically connected solid oxide fuel cells having an open end above a combustion zone into which the air feed tubes pass and a closed end near the inlet fuel plenum, where the open end of the fuel cells rest upon and within a separate combination ceramic seal and bundle support contained in a ceramic support casting, where at least one flexible cushion ceramic band seal located between the recuperator and fuel cells protects and controls horizontal thermal expansion, and where the fuel cells operate in the fuel cell mode and where the base support and bottom ceramic air exhaust manifolds carry from 85% to all of the weight of the generator.

  11. The electric field in capacitively coupled RF discharges: a smooth step model that includes thermal and dynamic effects

    Science.gov (United States)

    Brinkmann, Ralf Peter

    2015-12-01

    The electric field in radio-frequency driven capacitively coupled plasmas (RF-CCP) is studied, taking thermal (finite electron temperature) and dynamic (finite electron mass) effects into account. Two dimensionless numbers are introduced, the ratios ε ={λ\\text{D}}/l of the electron Debye length {λ\\text{D}} to the minimum plasma gradient length l (typically the sheath thickness) and η ={ω\\text{RF}}/{ω\\text{pe}} of the RF frequency {ω\\text{RF}} to the electron plasma frequency {ω\\text{pe}} . Assuming both numbers small but finite, an asymptotic expansion of an electron fluid model is carried out up to quadratic order inclusively. An expression for the electric field is obtained which yields (i) the space charge field in the sheath, (ii) the generalized Ohmic and ambipolar field in the plasma, and (iii) a smooth interpolation for the transition in between. The new expression is a direct generalization of the Advanced Algebraic Approximation (AAA) proposed by the same author (2009 J. Phys. D: Appl. Phys. 42 194009), which can be recovered for η \\to 0 , and of the established Step Model (SM) by Godyak (1976 Sov. J. Plasma Phys. 2 78), which corresponds to the simultaneous limits η \\to 0 , ε \\to 0 . A comparison of the hereby proposed Smooth Step Model (SSM) with a numerical solution of the full dynamic problem proves very satisfactory.

  12. Solvent vapor annealing of an insoluble molecular semiconductor

    KAUST Repository

    Amassian, Aram

    2010-01-01

    Solvent vapor annealing has been proposed as a low-cost, highly versatile, and room-temperature alternative to thermal annealing of organic semiconductors and devices. In this article, we investigate the solvent vapor annealing process of a model insoluble molecular semiconductor thin film - pentacene on SiO 2 exposed to acetone vapor - using a combination of optical reflectance and two-dimensional grazing incidence X-ray diffraction measurements performed in situ, during processing. These measurements provide valuable and new insight into the solvent vapor annealing process; they demonstrate that solvent molecules interact mainly with the surface of the film to induce a solid-solid transition without noticeable swelling, dissolving or melting of the molecular material. © 2010 The Royal Society of Chemistry.

  13. Irradiation, Annealing, and Reirradiation Effects on American and Russian Reactor Pressure Vessel Steels

    International Nuclear Information System (INIS)

    Chernobaeva, A.A.; Korolev, Y.N.; Nanstad, R.K.; Nikolaev, Y.A.; Sokolov, M.A.

    1998-01-01

    One of the options to mitigate the effects of irradiation on reactor pressure vessels (RPVs) is to thermally anneal them to restore the toughness properties that have been degraded by neutron irradiation. Even though a postirradiation anneal may be deemed successful, a critical aspect of continued RPV operation is the rate of embrittlement upon reirradiation. There are insufficient data available to allow for verification of available models of reirradiation embrittlement or for the development of a reliable predictive methodology. This is especially true in the case of fracture toughness data. Under the U.S.-Russia Joint Coordinating Committee for Civilian Nuclear Reactor Safety (JCCCNRS), Working Group 3 on Radiation Embrittlement, Structural Integrity, and Life Extension of Reactor Vessels and Supports agreed to conduct a comparative study of annealing and reirradiation effects on RPV steels. The Working Group agreed that each side would irradiate, anneal, reirradiate (if feasible ), and test two materials of the other. Charpy V-notch (CVN) and tensile specimens were included. Oak Ridge National Laboratory (ORNL) conducted such a program (irradiation and annealing, including static fracture toughness) with two weld metals representative of VVER-440 and VVER-1000 RPVs, while the Russian Research Center-Kurchatov Institute (RRC-KI) conducted a program (irradiation, annealing, reirradiation, and reannealing) with Heavy-Section Steel Technology (HSST) Program Plate 02 and Heavy-Section Steel Irradiation (HSSI) Program Weld 73W. The results for each material from each laboratory are compared with those from the other laboratory. The ORNL experiments with the VVER welds included irradiation to about 1 x 10 19 n/cm 2 (>1 MeV), while the RRC-KI experiments with the U.S. materials included irradiations from about 2 to 18 x 10 19 n/cm 2 (>l MeV). In both cases, irradiations were conducted at ∼290 C and annealing treatments were conducted at ∼454 C. The ORNL and RRC

  14. Irradiation, Annealing, and Reirradiation Effects on American and Russian Reactor Pressure Vessel Steels

    Energy Technology Data Exchange (ETDEWEB)

    Chernobaeva, A.A.; Korolev, Y.N.; Nanstad, R.K.; Nikolaev, Y.A.; Sokolov, M.A.

    1998-06-16

    One of the options to mitigate the effects of irradiation on reactor pressure vessels (RPVs) is to thermally anneal them to restore the toughness properties that have been degraded by neutron irradiation. Even though a postirradiation anneal may be deemed successful, a critical aspect of continued RPV operation is the rate of embrittlement upon reirradiation. There are insufficient data available to allow for verification of available models of reirradiation embrittlement or for the development of a reliable predictive methodology. This is especially true in the case of fracture toughness data. Under the U.S.-Russia Joint Coordinating Committee for Civilian Nuclear Reactor Safety (JCCCNRS), Working Group 3 on Radiation Embrittlement, Structural Integrity, and Life Extension of Reactor Vessels and Supports agreed to conduct a comparative study of annealing and reirradiation effects on RPV steels. The Working Group agreed that each side would irradiate, anneal, reirradiate (if feasible ), and test two materials of the other. Charpy V-notch (CVN) and tensile specimens were included. Oak Ridge National Laboratory (ORNL) conducted such a program (irradiation and annealing, including static fracture toughness) with two weld metals representative of VVER-440 and VVER-1000 RPVs, while the Russian Research Center-Kurchatov Institute (RRC-KI) conducted a program (irradiation, annealing, reirradiation, and reannealing) with Heavy-Section Steel Technology (HSST) Program Plate 02 and Heavy-Section Steel Irradiation (HSSI) Program Weld 73W. The results for each material from each laboratory are compared with those from the other laboratory. The ORNL experiments with the VVER welds included irradiation to about 1 x 10{sup 19} n/cm{sup 2} (>1 MeV), while the RRC-KI experiments with the U.S. materials included irradiations from about 2 to 18 x 10{sup 19} n/cm{sup 2} (>l MeV). In both cases, irradiations were conducted at {approximately}290 C and annealing treatments were conducted

  15. Radiation annealing in cuprous oxide

    DEFF Research Database (Denmark)

    Vajda, P.

    1966-01-01

    Experimental results from high-intensity gamma-irradiation of cuprous oxide are used to investigate the annealing of defects with increasing radiation dose. The results are analysed on the basis of the Balarin and Hauser (1965) statistical model of radiation annealing, giving a square-root relati......Experimental results from high-intensity gamma-irradiation of cuprous oxide are used to investigate the annealing of defects with increasing radiation dose. The results are analysed on the basis of the Balarin and Hauser (1965) statistical model of radiation annealing, giving a square...

  16. Influence of alloying and secondary annealing on anneal hardening ...

    Indian Academy of Sciences (India)

    Unknown

    Influence of alloying and secondary annealing on anneal hardening effect at sintered copper alloys. SVETLANA NESTOROVIC. Technical Faculty Bor, University of Belgrade, Bor, Yugoslavia. MS received 11 February 2004; revised 29 October 2004. Abstract. This paper reports results of investigation carried out on sintered ...

  17. GPU accelerated population annealing algorithm

    Science.gov (United States)

    Barash, Lev Yu.; Weigel, Martin; Borovský, Michal; Janke, Wolfhard; Shchur, Lev N.

    2017-11-01

    Population annealing is a promising recent approach for Monte Carlo simulations in statistical physics, in particular for the simulation of systems with complex free-energy landscapes. It is a hybrid method, combining importance sampling through Markov chains with elements of sequential Monte Carlo in the form of population control. While it appears to provide algorithmic capabilities for the simulation of such systems that are roughly comparable to those of more established approaches such as parallel tempering, it is intrinsically much more suitable for massively parallel computing. Here, we tap into this structural advantage and present a highly optimized implementation of the population annealing algorithm on GPUs that promises speed-ups of several orders of magnitude as compared to a serial implementation on CPUs. While the sample code is for simulations of the 2D ferromagnetic Ising model, it should be easily adapted for simulations of other spin models, including disordered systems. Our code includes implementations of some advanced algorithmic features that have only recently been suggested, namely the automatic adaptation of temperature steps and a multi-histogram analysis of the data at different temperatures. Program Files doi:http://dx.doi.org/10.17632/sgzt4b7b3m.1 Licensing provisions: Creative Commons Attribution license (CC BY 4.0) Programming language: C, CUDA External routines/libraries: NVIDIA CUDA Toolkit 6.5 or newer Nature of problem: The program calculates the internal energy, specific heat, several magnetization moments, entropy and free energy of the 2D Ising model on square lattices of edge length L with periodic boundary conditions as a function of inverse temperature β. Solution method: The code uses population annealing, a hybrid method combining Markov chain updates with population control. The code is implemented for NVIDIA GPUs using the CUDA language and employs advanced techniques such as multi-spin coding, adaptive temperature

  18. Models of low-mass helium white dwarfs including gravitational settling, thermal and chemical diffusion, and rotational mixing

    Science.gov (United States)

    Istrate, A. G.; Marchant, P.; Tauris, T. M.; Langer, N.; Stancliffe, R. J.; Grassitelli, L.

    2016-10-01

    A large number of extremely low-mass helium white dwarfs (ELM WDs) have been discovered in recent years. The majority of them are found in close binary systems suggesting they are formed either through a common-envelope phase or via stable mass transfer in a low-mass X-ray binary (LMXB) or a cataclysmic variable (CV) system. Here, we investigate the formation of these objects through the LMXB channel with emphasis on the proto-WD evolution in environments with different metallicities. We study for the first time the combined effects of rotational mixing and element diffusion (e.g. gravitational settling, thermal and chemical diffusion) on the evolution of proto-WDs and on the cooling properties of the resulting WDs. We present state-of-the-art binary stellar evolution models computed with MESA for metallicities of Z = 0.02, 0.01, 0.001 and 0.0002, producing WDs with masses between 0.16-0.45 M⊙. Our results confirm that element diffusion plays a significant role in the evolution of proto-WDs that experience hydrogen shell flashes. The occurrence of these flashes produces a clear dichotomy in the cooling timescales of ELM WDs, which has important consequences e.g. for the age determination of binary millisecond pulsars. In addition, we confirm that the threshold mass at which this dichotomy occurs depends on metallicity. Rotational mixing is found to counteract the effect of gravitational settling in the surface layers of young, bloated ELM proto-WDs and therefore plays a key role in determining their surface chemical abundances, I.e. the observed presence of metals in their atmospheres. We predict that these proto-WDs have helium-rich envelopes through a significant part of their lifetime. This is of great importance as helium is a crucial ingredient in the driving of the κ-mechanism suggested for the newly observed ELM proto-WD pulsators. However, we find that the number of hydrogen shell flashes and, as a result, the hydrogen envelope mass at the beginning of

  19. Thermo-economic optimization of the impact of renewable generators on poly-generation smart-grids including hot thermal storage

    International Nuclear Information System (INIS)

    Rivarolo, M.; Greco, A.; Massardo, A.F.

    2013-01-01

    Highlights: ► We model a poly-generation grid including thermal storage and renewable generators. ► We analyze the impact of random renewable generators on the grid performance. ► We carry out the grid optimization using a time-dependent thermo-economic approach. ► We present the importance of the storage system to optimize the RES impact. - Abstract: In this paper, the impact of not controllable renewable energy generators (wind turbines and solar photovoltaic panels) on the thermo-economic optimum performance of poly-generation smart grids is investigated using an original time dependent hierarchical approach. The grid used for the analysis is the one installed at the University of Genoa for research activities. It is based on different prime movers: (i) 100 kWe micro gas turbine, (ii) 20 kWe internal combustion engine powered by gases to produce both electrical and thermal (hot water) energy and (iii) a 100 kWth adsorption chiller to produce cooling (cold water) energy. The grid includes thermal storage tanks to manage the thermal demand load during the year. The plant under analysis is also equipped with two renewable non-controllable generators: a small size wind turbine and photovoltaic solar panels. The size and the management of the system studied in this work have been optimized, in order to minimize both capital and variable costs. A time-dependent thermo-economic hierarchical approach developed by the authors has been used, considering the time-dependent electrical, thermal and cooling load demands during the year as problem constraints. The results are presented and discussed in depth and show the strong interaction between fossil and renewable resources, and the importance of an appropriate storage system to optimize the RES impact taking into account the multiproduct character of the grid under investigation.

  20. Electrical conductivity, dielectric permittivity and thermal properties of the compound aqua[bis(2-dimethylaminomethyl-4-NIT-phenolato)] copper(II) including NaCl impurity

    International Nuclear Information System (INIS)

    Yakuphanoglu, F.; Aydogdu, Y.; Schatzschneider, U.; Rentschler, E.

    2003-01-01

    The AC and DC conductivity, the dielectric permittivity and the thermal properties of the compound aqua[bis(2-dimethylaminomethyl-4-NIT-phenolato)] copper(II) including NaCl impurity were investigated. The AC conductivity follows a power law of the frequency σ(ω)∝ω s . At high frequency, where s is dependent of temperature, the conduction mechanism is reasonably well interpreted in terms of the correlated barrier hopping model. The DC conductivity indicates classical semiconductor behavior. So, it is evaluated that the sample is a typical inorganic semiconductor as its conductivity increases with increasing temperature and the electronic parameters such as activation energy and room-temperature conductivity are in the regime of semiconductors. It is also found that the dielectric constant and the dielectric loss values decrease with frequency and increase with temperature. The thermal properties were investigated under non-isothermal conditions by thermogravimetry (TGA) and differential scanning calorimetry (DSC). The kinetic parameters such as the order of the reaction, the activation energy (E), enthalpy of formation (ΔH) and characteristic temperatures of the exothermic peak were determined by means of the TGA and DSC techniques. The thermal conductivity shows enhancement with increasing temperature and, in the thermal conductivity mechanism, dominates transport of electrons

  1. Toward understanding dynamic annealing processes in irradiated ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Myers, Michael Thomas [Texas A & M Univ., College Station, TX (United States)

    2013-05-01

    High energy particle irradiation inevitably generates defects in solids. The ballistic formation and thermalization of the defect creation process occur rapidly, and are believed to be reasonably well understood. However, knowledge of the evolution of defects after damage cascade thermalization, referred to as dynamic annealing, is quite limited. Unraveling the mechanisms associated with dynamic annealing is crucial since such processes play an important role in the formation of stable postirradiation disorder in ion-beam-processing of semiconductors, and determines the “radiation tolerance” of many nuclear materials. The purpose of this dissertation is to further our understanding of the processes involved in dynamic annealing. In order to achieve this, two main tasks are undertaken.

  2. Stored energy and annealing behavior of heavily deformed aluminium

    DEFF Research Database (Denmark)

    Kamikawa, Naoya; Huang, Xiaoxu; Kondo, Yuka

    2012-01-01

    are quantified such as boundary spacing, misorientation angle and dislocation density for 99.99% aluminium deformed by accumulative roll-bonding to a strain of 4.8. Two different annealing processes have been applied; (i) one-step annealing for 0.5 h at 100-400°C and (ii) two-step annealing for 6 h at 175°C......It has been demonstrated in previous work that a two-step annealing treatment, including a low-temperature, long-time annealing and a subsequent high-temperature annealing, is a promising route to control the microstructure of a heavily deformed metal. In the present study, structural parameters...... followed by 0.5 h annealing at 200-600°C, where the former treatment leads to discontinuous recrystallization and the latter to uniform structural coarsening. This behavior has been analyzed in terms of the relative change during annealing of energy stored as elastic energy in the dislocation structure...

  3. Radiation annealing in cuprous oxide

    DEFF Research Database (Denmark)

    Vajda, P.

    1966-01-01

    Experimental results from high-intensity gamma-irradiation of cuprous oxide are used to investigate the annealing of defects with increasing radiation dose. The results are analysed on the basis of the Balarin and Hauser (1965) statistical model of radiation annealing, giving a square...

  4. Formation of oxygen related donors in step-annealed CZ–silicon

    Indian Academy of Sciences (India)

    Unknown

    anneal of 10 h followed by annealing of 10 h ... But it leaves some problems with a mark of interrogation, such as the exact kinetics of thermal ... desired heat treatment and the concentrations of oxygen. (Oi) and carbon (Cs) are again measured with ...

  5. Effect of microwave annealing on electrical characteristics of TiN/Al/TiN/HfO2/Si MOS capacitors

    Science.gov (United States)

    Shih, Tzu-Lang; Su, Yin-Hsien; Kuo, Tai-Chen; Lee, Wen-Hsi; Current, Michael Ira

    2017-07-01

    In this letter, microwave annealing over a wide range of power (300-2700 W) in nitrogen ambient was performed on TiN/Al/TiN/HfO2/Si metal-oxide-semiconductor capacitors. Capacitors with rapid thermal annealing at 500 °C were also fabricated for comparison at the same wafer temperature measured during microwave annealing at 2700 W. For microwave annealed capacitors, key parameters such as equivalent oxide thickness, interface state density, oxide trapped charge, leakage current density, and breakdown voltage were all improved with increasing microwave annealing power. For the capacitor with rapid thermal annealing at 500 °C, diffusion of Al into TiN and growth of the interfacial oxide layer are detected, leading to the shift in flat-band voltage and increase in equivalent oxide thickness, respectively. The results further indicate that it is more effective to remove the charged traps by microwave annealing than by rapid thermal annealing, and the reduction in leakage current density after microwave annealing corresponds to the reduction in charge traps based on a trap-assisted tunneling model. With no trade-off relationship between the electrical characteristics and no undesired effect such as diffusion of species, microwave annealing demonstrates great potential for the post-metallization annealing process for the high-k/metal gate structure.

  6. Effective dopant activation by susceptor-assisted microwave annealing of low energy boron implanted and phosphorus implanted silicon

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Zhao; Vemuri, Rajitha N. P.; Alford, T. L., E-mail: TA@asu.edu [School of Matter, Transport, and Energy, Arizona State University, Tempe, Arizona 85287 (United States); David Theodore, N. [CHD-Fab, Freescale Semiconductor Inc., 1300 N. Alma School Rd., Chandler, Arizona 85224 (United States); Lu, Wei; Lau, S. S. [Department of Electrical Engineering, University of California, San Diego, California 92093 (United States); Lanz, A. [Department of Mathematics, Norfolk State University, Norfolk, Virginia 23504 (United States)

    2013-12-28

    Rapid processing and reduced end-of-range diffusion result from susceptor-assisted microwave (MW) annealing, making this technique an efficient processing alternative for electrically activating dopants within ion-implanted semiconductors. Sheet resistance and Hall measurements provide evidence of electrical activation. Susceptor-assisted MW annealing, of ion-implanted Si, enables more effective dopant activation and at lower temperatures than required for rapid thermal annealing (RTA). Raman spectroscopy and ion channeling analyses are used to monitor the extent of ion implantation damage and recrystallization. The presence and behavior of extended defects are monitored by cross-section transmission electron microscopy. Phosphorus implanted Si samples experience effective electrical activation upon MW annealing. On the other hand, when boron implanted Si is MW annealed, the growth of extended defects results in reduced crystalline quality that hinders the electrical activation process. Further comparison of dopant diffusion resulting from MW annealing and rapid thermal annealing is performed using secondary ion mass spectroscopy. MW annealed ion implanted samples show less end-of-range diffusion when compared to RTA samples. In particular, MW annealed P{sup +} implanted samples achieve no visible diffusion and equivalent electrical activation at a lower temperature and with a shorter time-duration of annealing compared to RTA. In this study, the peak temperature attained during annealing does not depend on the dopant species or dose, for susceptor-assisted MW annealing of ion-implanted Si.

  7. Post-annealing effects on pulsed laser deposition-grown GaN thin films

    International Nuclear Information System (INIS)

    Cheng, Yu-Wen; Wu, Hao-Yu; Lin, Yu-Zhong; Lee, Cheng-Che; Lin, Ching-Fuh

    2015-01-01

    In this work, the post-annealing effects on gallium nitride (GaN) thin films grown from pulsed laser deposition (PLD) are investigated. The as-deposited GaN thin films grown from PLD are annealed at different temperatures in nitrogen ambient. Significant changes of the GaN crystal properties are observed. Raman spectroscopy is used to observe the crystallinity, the change of residual stress, and the thermal decomposition of the annealed GaN thin films. X-ray diffraction is also applied to identify the crystal phase of GaN thin films, and the surface morphology of GaN thin films annealed at different temperatures is observed by scanning electron microscopy. Through the above analyses, the GaN thin films grown by PLD undergo three stages: phase transition, stress alteration, and thermal decomposition. At a low annealing temperature, the rock salt GaN in GaN films is transformed into wurtzite. The rock salt GaN diminishes with increasing annealing temperature. At a medium annealing temperature, the residual stress of the film changes significantly from compressive strain to tensile strain. As the annealing temperature further increases, the GaN undergoes thermal decomposition and the surface becomes granular. By investigating the annealing temperature effects and controlling the optimized annealing temperature of the GaN thin films, we are able to obtain highly crystalline and strain-free GaN thin films by PLD. - Highlights: • The GaN thin film is grown on sapphire by pulsed laser deposition. • The GaN film undergoes three stages with increasing annealing temperature. • In the first stage, the film transfers from rock salt to wurtzite phase. • In the second stage, the stress in film changes from compressive to tensile. • In the final stage, the film thermally decomposes and becomes granular

  8. Annealing and etching effects on strain and stress sensitivity of polymer optical fibre Bragg grating sensors

    DEFF Research Database (Denmark)

    Pospori, A.; Marques, C. A.F.; Sáez-Rodríguez, D.

    2017-01-01

    Thermal annealing and chemical etching effects on the strain and stress sensitivity of polymer optical fibre based sensors are investigated. Bragg grating sensors have been photo-inscribed in PMMA optical fibre and their strain and stress sensitivity has been characterised before and after any...... annealing or etching process. The annealing and etching processes have been tried in different sequence in order to investigate their impact on the sensor's performance. Results show with high confidence that fibre annealing can improve both strain and stress sensitivities. The fibre etching can also...

  9. Numerical analysis on effect of annealing mc-Si ingot grown by DS process for PV application

    Science.gov (United States)

    Aravindan, G.; Srinivasan, M.; Aravinth, K.; Ramasamy, P.

    2017-10-01

    Silicon solar cells play a crucial role in Photo voltaic (PV) application. We have numerically investigated thermal stress and normal stress components (Sigma 11, Sigma 22, Sigma 33 and sigma 12) by using finite volume method. The maximum thermal stress has low value at the centre region for 900 K and 700 K annealing temperatures comparing all the cases. The maximum thermal stress at peripheral region is low for 700 K annealing compared to 900 K annealing. The annealing effect of mc-Si ingot normal stress components is discussed. At 700 K annealing temperature the normal stress in 11 and 33 direction has lower maximum and at the 900 K annealing temperature the normal stress in 22 and 12 direction has lower maximum.

  10. Laser annealing heals radiation damage in avalanche photodiodes

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Jin Gyu [University of Waterloo, Institute for Quantum Computing, Waterloo, ON (Canada); University of Waterloo, Department of Electrical and Computer Engineering, Waterloo, ON (Canada); Anisimova, Elena; Higgins, Brendon L.; Bourgoin, Jean-Philippe [University of Waterloo, Institute for Quantum Computing, Waterloo, ON (Canada); University of Waterloo, Department of Physics and Astronomy, Waterloo, ON (Canada); Jennewein, Thomas [University of Waterloo, Institute for Quantum Computing, Waterloo, ON (Canada); University of Waterloo, Department of Physics and Astronomy, Waterloo, ON (Canada); Canadian Institute for Advanced Research, Quantum Information Science Program, Toronto, ON (Canada); Makarov, Vadim [University of Waterloo, Institute for Quantum Computing, Waterloo, ON (Canada); University of Waterloo, Department of Electrical and Computer Engineering, Waterloo, ON (Canada); University of Waterloo, Department of Physics and Astronomy, Waterloo, ON (Canada)

    2017-12-15

    Avalanche photodiodes (APDs) are a practical option for space-based quantum communications requiring single-photon detection. However, radiation damage to APDs significantly increases their dark count rates and thus reduces their useful lifetimes in orbit. We show that high-power laser annealing of irradiated APDs of three different models (Excelitas C30902SH, Excelitas SLiK, and Laser Components SAP500S2) heals the radiation damage and several APDs are restored to typical pre-radiation dark count rates. Of nine samples we test, six APDs were thermally annealed in a previous experiment as another solution to mitigate the radiation damage. Laser annealing reduces the dark count rates further in all samples with the maximum dark count rate reduction factor varying between 5.3 and 758 when operating at -80 C. This indicates that laser annealing is a more effective method than thermal annealing. The illumination power to reach these reduction factors ranges from 0.8 to 1.6 W. Other photon detection characteristics, such as photon detection efficiency, timing jitter, and afterpulsing probability, fluctuate but the overall performance of quantum communications should be largely unaffected by these variations. These results herald a promising method to extend the lifetime of a quantum satellite equipped with APDs. (orig.)

  11. Effect of annealing on field emission properties of nanodiamond coating

    Energy Technology Data Exchange (ETDEWEB)

    Zhai, C.X., E-mail: zhaicatty@126.co [School of Information Science and Technology, Northwest University, Xi' an 710127, Shaanxi (China); Yun, J.N.; Zhao, L.L.; Zhang, Z.Y.; Wang, X.W.; Chen, Y.Y. [School of Information Science and Technology, Northwest University, Xi' an 710127, Shaanxi (China)

    2011-03-01

    Field electron emission of detonation nanodiamond (ND) coated on a titanium substrate by electrophoretic deposition is investigated. It is found that thermal annealing can significantly improve the field emission properties of the ND layer, which can be mainly attributed to the formation of the TiC phase between diamond and Ti. The first-principles calculated results show that the formation of transition layers can lower the interface barrier and enhance the field electron emission of ND coating. Besides, the transformation of diamond to graphite after annealing has been revealed by Raman spectra. This transformation also benefits the electron emission enhancement.

  12. Nanoparticle Precipitation in Irradiated and Annealed Ceria Doped with Metals for Emulation of Spent Fuels

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Weilin [Pacific Northwest National Laboratory, P.O. Box; Conroy, Michele A. [Pacific Northwest National Laboratory, P.O. Box; Kruska, Karen [Pacific Northwest National Laboratory, P.O. Box; Overman, Nicole R. [Pacific Northwest National Laboratory, P.O. Box; Droubay, Timothy C. [Pacific Northwest National Laboratory, P.O. Box; Gigax, Jonathan [Texas A& amp,M University, 3380; Shao, Lin [Texas A& amp,M University, 3380; Devanathan, Ram [Pacific Northwest National Laboratory, P.O. Box

    2017-09-29

    Epsilon alloy precipitates have been observed with varied compositions and sizes in spent nuclear fuels, such as UO2. Presence of the inclusions, along with other oxide precipitates, gas bubbles and irradiation-induced structural defects, can significantly degrade the physical properties of the fuel. To predict fuel performance, a fundamental study of the precipitation processes is needed. This study uses ceria (CeO2) as a surrogate for UO2. Polycrystalline CeO2 films doped with Mo, Ru, Rh, Pd and Re (surrogate for Tc) were grown at 823 K using pulsed laser deposition, irradiated at 673 K with He+ ions, and subsequently annealed at higher temperatures. A number of methods, including transmission electron microscopy and atom probe tomography, were applied to characterize the samples. The results indicate that there is a uniform distribution of the doped metals in the as-grown CeO2 film. Pd particles of ~3 nm in size appear near dislocation edges after He+ ion irradiation to ~13 dpa. Thermal annealing at 1073 K in air leads to formation of precipitates with Mo and Pd around grain boundaries. Further annealing at 1373 K produces 70 nm sized precipitates with small grains at cavities.

  13. NRC assessment of the Department of Energy annealing demonstration project

    International Nuclear Information System (INIS)

    Jackson, D.A.; Malik, S.N.

    1997-01-01

    Thermal annealing is the only known method for mitigating the effects of neutron irradiation embrittlement in reactor pressure vessel (RPV) steels. In May 1996, the US Department of Energy (DOE) in conjunction with the American Society of Mechanical Engineers, Westinghouse, Cooperheat, Electric Power Research Institute (with participating utilities), Westinghouse Owner's Group, Consumers Power, Electricite' de France, Duquesne Light and the Central Research Institute of the Electric Power Industry (Japan) sponsored an annealing demonstration project (ADP) at Marble Hill. The Marble Hill Plant, located in Madison, Indiana, is a Westinghouse 4 loop design. The plant was nearly 70% completed when the project was canceled. Hence, the RPV was never irradiated. The paper will present highlights from the NRCs independent evaluation of the Marble Hill Annealing Demonstration Project

  14. Molecular dynamics simulation of annealed ZnO surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Min, Tjun Kit; Yoon, Tiem Leong [School of Physics, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Lim, Thong Leng [Faculty of Engineering and Technology, Multimedia University, Melaka Campus, 75450 Melaka (Malaysia)

    2015-04-24

    The effect of thermally annealing a slab of wurtzite ZnO, terminated by two surfaces, (0001) (which is oxygen-terminated) and (0001{sup ¯}) (which is Zn-terminated), is investigated via molecular dynamics simulation by using reactive force field (ReaxFF). We found that upon heating beyond a threshold temperature of ∼700 K, surface oxygen atoms begin to sublimate from the (0001) surface. The ratio of oxygen leaving the surface at a given temperature increases as the heating temperature increases. A range of phenomena occurring at the atomic level on the (0001) surface has also been explored, such as formation of oxygen dimers on the surface and evolution of partial charge distribution in the slab during the annealing process. It was found that the partial charge distribution as a function of the depth from the surface undergoes a qualitative change when the annealing temperature is above the threshold temperature.

  15. Performance analysis of the Companhia Siderugica Nacional boxes 1 and 2 annealing line furnaces coating; Analise de desempenho do revestimento dos fornos das linhas de recozimento em caixa 1 e 2 da Companhia Siderugica Nacional

    Energy Technology Data Exchange (ETDEWEB)

    Cruz, Genesio Moreira da [Companhia Siderurgica Nacional, Volta Redonda, RJ (Brazil)]|[Universidade Federal Fluminense, Niteroi, RJ (Brazil); Vaz, Eduardo Ribeiro; Souza Ferraz, Urbano de; Rodrigues, Alessandro J.G.

    1995-12-31

    This work analyzes coatings used in the boxes 1 and 2 annealing line furnaces of the Companhia Siderurgica Nacional. Insulator refractory bricks from the original project are compared with thermal insulator coatings used in the annealing line 2.

  16. Evolution of microstructure at hot band annealing of ferritic FeSi steels

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, Jürgen, E-mail: juergen.schneider@t-online.de [Institute of Metal Forming, Technische Universität Bergakademie Freiberg, Bernhard-von Cotta-Str. 4, D-09596 Freiberg (Germany); Stahlzentrum Freiberg e.V., Leipziger Straße 34, D-09599 Freiberg (Germany); Li, Guangqiang [State Key Lab. of Refractories and Metallurgy, Wuhan University of Science and Technology, No. 947 Heping Avenue, Qingshan District, Wuhan 430081 (China); Franke, Armin [Stahlzentrum Freiberg e.V., Leipziger Straße 34, D-09599 Freiberg (Germany); Zhou, Bowen [State Key Lab. of Refractories and Metallurgy, Wuhan University of Science and Technology, No. 947 Heping Avenue, Qingshan District, Wuhan 430081 (China)

    2017-02-15

    The magnetic properties of the finally fabricated nonoriented FeSi steels critically depend on the microstructure and on the occurring crystallographic texture. The fabrication route comprises hot rolling, coiling and cooling, hot band annealing before cold rolling (optional), cold rolling and the final thermal treatment. As well known there is an interplay between the microstructure and texture during the various processing steps. For that reason, it is of interest to know more on the evolution of the microstructure at hot band annealing of hot band prepared in different ways. In this paper we will summarize our recent results on the evolution of microstructure during thermal annealing of hot band: thermal treatment following immediately the last pass of hot rolling or a hot band annealing as a separate processing step before cold rolling.

  17. Liquid nitrogen enhancement of partially annealed fission tracks in glass

    International Nuclear Information System (INIS)

    Pilione, L.J.; Gold, D.P.

    1976-01-01

    It is known that the number density of fission tracks in solids is reduced if the sample is heated before chemical etching, and the effect of annealing must be allowed for before an age can be assigned to the sample. The extent of annealing can be determined by measuring the reduction of track parameters (diameter and/or length) and comparison with unannealed tracks. Correct ages can be obtained by careful calibration studies of track density reduction against track diameter or length reduction at different annealing temperatures and times. For crystallised minerals, however, the resulting correction techniques are not generally valid. In the experimental work described glass samples were partially annealed and then immersed in liquid N 2 for various periods, and it was shown that the properties of the glass and the track parameters could be altered so as to observe tracks that would normally be erased by annealing. The results of track density measurements against liquid N 2 immersion times are shown graphically. A gain of about 40% was achieved after 760 hours immersion time. The size of the tracks was not noticeably affected by the immersion. It was thought that thermal shock might be the cause of the track enhancement, but it was found that repeated immersion for about 2 hours did not lead to an increase in track density. Other studies suggest that the mechanism that erases the tracks through annealing may be partially reversed when the temperature of the sample is significantly lowered for a sufficient length of time. Further work is under way to find whether or not the process of enhancement is a reversal of the annealing process. Similar enhancement effects using liquid N 2 have been observed for d-particle tracks in polycarbonate detectors. (U.K.)

  18. Controlling CH3NH3PbI(3-x)Cl(x) Film Morphology with Two-Step Annealing Method for Efficient Hybrid Perovskite Solar Cells.

    Science.gov (United States)

    Liu, Dong; Wu, Lili; Li, Chunxiu; Ren, Shengqiang; Zhang, Jingquan; Li, Wei; Feng, Lianghuan

    2015-08-05

    The methylammonium lead halide perovskite solar cells have become very attractive because they can be prepared with low-cost solution-processable technology and their power conversion efficiency have been increasing from 3.9% to 20% in recent years. However, the high performance of perovskite photovoltaic devices are dependent on the complicated process to prepare compact perovskite films with large grain size. Herein, a new method is developed to achieve excellent CH3NH3PbI3-xClx film with fine morphology and crystallization based on one step deposition and two-step annealing process. This method include the spin coating deposition of the perovskite films with the precursor solution of PbI2, PbCl2, and CH3NH3I at the molar ratio 1:1:4 in dimethylformamide (DMF) and the post two-step annealing (TSA). The first annealing is achieved by solvent-induced process in DMF to promote migration and interdiffusion of the solvent-assisted precursor ions and molecules and realize large size grain growth. The second annealing is conducted by thermal-induced process to further improve morphology and crystallization of films. The compact perovskite films are successfully prepared with grain size up to 1.1 μm according to SEM observation. The PL decay lifetime, and the optic energy gap for the film with two-step annealing are 460 ns and 1.575 eV, respectively, while they are 307 and 327 ns and 1.577 and 1.582 eV for the films annealed in one-step thermal and one-step solvent process. On the basis of the TSA process, the photovoltaic devices exhibit the best efficiency of 14% under AM 1.5G irradiation (100 mW·cm(-2)).

  19. Thermal annealing of high dose radiation induced damage at room temperature in alkaline. Stored energy, thermoluminescence and coloration; Aniquilacion termica de dano inducido por irradiacion a altas dosis en haluros alcalinos a 300 k. energia almacenda. Termoluminiscencia y coloracion

    Energy Technology Data Exchange (ETDEWEB)

    Delgado, L.

    1980-07-01

    The possible relation between stored energy, thermoluminescence and colour centre annealing in gamma and electron irradiated alkali halides is studied. Thermoluminescence occurs at temperature higher than the temperature at which the main stored energy peak appears. No stored energy release is detected in additively coloured KC1 samples. Plastic deformation and doping with Ca and Sr induce a stored energy spectrum different from the spectrum observed in pure and as cleaved samples, but the amount of stored energy does not change for a given irradiation dose.Capacity of alkali halides to store energy by irradiation increases as the cation size decreases. (Author) 51 refs.

  20. Improvement on the electrical characteristics of Pd/HfO{sub 2}/6H-SiC MIS capacitors using post deposition annealing and post metallization annealing

    Energy Technology Data Exchange (ETDEWEB)

    Esakky, Papanasam, E-mail: papanasamte@gmail.com; Kailath, Binsu J

    2017-08-15

    Highlights: • Post deposition annealing (PDA) and post metallization annealing (PMA) on the electrical characteristics of Pd/HfO{sub 2}/6H-SiC MIS capacitors. • Post deposition N{sub 2}O plasma annealing inhibits crystallization of HfO{sub 2} during high temperature annealing. • Plasma annealing followed by RTA in N{sub 2} results in formation of hafnium silicate at the HfO{sub 2}-SiC interface. • PDA reduces interface state density (D{sub it}) and gate leakage current density (J{sub g}) by order. • PMA in forming gas for 40 min results in better passivation and reduces D{sub it} by two orders and J{sub g} by thrice. - Abstract: HfO{sub 2} as a gate dielectric enables high electric field operation of SiC MIS structure and as gas sensor HfO{sub 2}/SiC capacitors offer higher sensitivity than SiO{sub 2}/SiC capacitors. The issue of higher density of oxygen vacancies and associated higher leakage current necessitates better passivation of HfO{sub 2}/SiC interface. Effect of post deposition annealing in N{sub 2}O plasma and post metallization annealing in forming gas on the structural and electrical characteristics of Pd/HfO{sub 2}/SiC MIS capacitors are reported in this work. N{sub 2}O plasma annealing suppresses crystallization during high temperature annealing thereby improving the thermal stability and plasma annealing followed by rapid thermal annealing in N{sub 2} result in formation of Hf silicate at the HfO{sub 2}/SiC interface resulting in order of magnitude lower density of interface states and gate leakage current. Post metallization annealing in forming gas for 40 min reduces interface state density by two orders while gate leakage current density is reduced by thrice. Post deposition annealing in N{sub 2}O plasma and post metallization annealing in forming gas are observed to be effective passivation techniques improving the electrical characteristics of HfO{sub 2}/SiC capacitors.

  1. Influence of Annealing Temperature on the Characteristics of Ti-Codoped GZO Thin Solid Film

    Directory of Open Access Journals (Sweden)

    Tao-Hsing Chen

    2013-01-01

    Full Text Available This study utilizes radio frequency magnetron sputtering (RF sputtering to deposit GZO transparent conductive film and Ti thin film on the same corning glass substrate and then treats GZO/Ti thin film with rapid thermal annealing. The annealing temperatures are 300°C , 500°C, and 550°C, respectively. Ti:GZO transparent conductive oxide (TCO thin films are deposited on glass substrates using a radio frequency magnetron sputtering technique. The thin films are then annealed at temperatures of 300°C, 500°C, and 550°C, respectively, for rapid thermal annealing. The effects of the annealing temperature on the optical properties, resistivity, and nanomechanical properties of the Ti:GZO thin films are then systematically explored. The results show that all of the annealed films have excellent transparency (~90% in the visible light range. Moreover, the resistivity of the Ti:GZO films reduces with an increasing annealing temperature, while the carrier concentration and Hall mobility both increase. Finally, the hardness and Young’s modulus of the Ti:GZO thin films are both found to increase as the annealing temperature is increased.

  2. High pressure annealing of Europium implanted GaN

    KAUST Repository

    Lorenz, K.

    2012-02-09

    GaN epilayers were implanted with Eu to fluences of 1×10^13 Eu/cm2 and 1×10^15 Eu/cm2. Post-implant thermal annealing was performed in ultra-high nitrogen pressures at temperatures up to 1450 ºC. For the lower fluence effective structural recovery of the crystal was observed for annealing at 1000 ºC while optical activation could be further improved at higher annealing temperatures. The higher fluence samples also reveal good optical activation; however, some residual implantation damage remains even for annealing at 1450 ºC which leads to a reduced incorporation of Eu on substitutional sites, a broadening of the Eu luminescence lines and to a strongly reduced fraction of optically active Eu ions. Possibilities for further optimization of implantation and annealing conditions are discussed.© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

  3. Annealing studies of substoichiometric amorphous SiO{sub x} layers for c-Si surface passivation

    Energy Technology Data Exchange (ETDEWEB)

    Einsele, F.; Beyer, W.; Rau, U. [IEF-5 Photovoltaik, Forschungszentrum Juelich GmbH, 52425 Juelich (Germany)

    2010-04-15

    We investigate thermal stability of amorphous substoichiometric silicon-oxide alloys with oxygen concentrations from 0 to 10 at-%. Annealing experiments, including effective lifetime measurements, hydrogen effusion, and infrared absorption spectroscopy, yield a surface passivation on p-type float-zone crystalline silicon wafers with maximum effective lifetimes up to 1.5 ms. The thermal stability of the passivation increases with increasing oxygen concentration of the films. For oxygen concentrations above 5%, we observe a decrease of passivation due to the formation of voids in the material, which shows in a low temperature peak of the H effusion spectra. Annealing leads to a structural transition of the material which is accompanied by an increase in effective lifetime. The stretching mode absorptions of Si- O-Si molecular vibrations near 1000 cm{sup -1} shift towards higher wavenumbers, both with increased oxygen concentration and upon annealing of the films. For increased oxygen concentrations, the Si-H stretching modes shift from predominantly 2000 cm{sup -1} to 2090 cm{sup -1}.(copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  4. Analyses of residual iron in carbon nanotubes produced by camphor/ferrocene pyrolysis and purified by high temperature annealing

    Energy Technology Data Exchange (ETDEWEB)

    Antunes, E.F., E-mail: ericafa@las.inpe.br [Instituto Tecnologico de Aeronautica (ITA), Praca Marechal Eduardo Gomes, 50, CEP 12.228-900, Sao Jose dos Campos, SP (Brazil); Instituto Nacional de Pesquisas Espaciais (INPE), Av. dos Astronautas, 1758, CEP 12.227-010, Sao Jose dos Campos, SP (Brazil); Resende, V.G. de; Mengui, U.A. [Instituto Nacional de Pesquisas Espaciais (INPE), Av. dos Astronautas, 1758, CEP 12.227-010, Sao Jose dos Campos, SP (Brazil); Cunha, J.B.M. [Universidade Federal do Rio Grande do Sul (UFRGS), Av. Bento Goncalves, 9500, CEP 91.501-970, Porto Alegre, RS (Brazil); Corat, E.J.; Massi, M. [Instituto Nacional de Pesquisas Espaciais (INPE), Av. dos Astronautas, 1758, CEP 12.227-010, Sao Jose dos Campos, SP (Brazil)

    2011-07-01

    A detailed analysis of iron-containing phases in multiwall carbon nanotube (MWCNT) powder was carried out. The MWCNTs were produced by camphor/ferrocene and purified by high temperature annealing in an oxygen-free atmosphere (N{sub 2} or VC). Thermogravimetric analysis, Moessbauer spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopy enabled the evaluation of the residual iron in MWCNTs after purification. The VC treatments provided MWCNTs with a purity degree higher than 99%. Moreover, Raman spectroscopy revealed a significant improvement in graphitic ordering after thermal annealing. A brief description of the mechanism of iron removal was included. We highlight the mobility of iron atoms through graphitic sheets and the large contact angle of iron clusters formed on MWCNT surfaces at high temperatures.

  5. The effect of post annealing treatment on the citrate sol-gel derived nanocrystalline BaFe12O19 powder: structural, morphological, optical and magnetic properties

    Science.gov (United States)

    Brightlin, B. C.; Balamurugan, S.

    2016-11-01

    The nanocrystalline BaFe12O19 powders were obtained from citrate sol-gel combustion-derived powder upon annealing at 800-1100 °C, and explored their structural, micro-structural, optical and magnetic properties. The thermal decomposition of citrate sol-gel combustion product was verified by means of thermogravimetric and differential thermal analysis. Structural identification of the citrate sol-gel combustion powder and annealed samples were investigated by powder X-ray diffraction. Though the combustion product exhibits cubic spinel phase material, the annealed powder yields good quality nanocrystalline hexagonal BaFe12O19 phase materials. The thin plate-like flakes morphology with random particle sizes of 100-200 nm with slightly agglomerated particles of BaFe12O19 phase is analyzed by high resolution scanning electron microscopy for the good quality annealed sample. Photoluminescence emission spectrum of BaFe12O19 material reveals broad emission peak at 360 nm under the excitation wavelength of 270 nm. Interestingly, the near infrared relative reflectivity of the nanocrystalline BaFe12O19 materials obtained by citrate sol-gel synthesis method is higher than the nanocrystalline BaFe12O19 materials obtained by mechano-thermal and co-precipitation method. The present dark brown colored BaFe12O19 materials can be applied as a ceramic color pigment which includes several applications. The room temperature magnetic hysteresis loop of the annealed BaFe12O19 sample exhibits a ferromagnetic saturation magnetization, M s of 55.774 emu/g at 15 kOe.

  6. The effect of post annealing treatment on the citrate sol–gel derived nanocrystalline BaFe12O19 powder: structural, morphological, optical and magnetic properties

    Directory of Open Access Journals (Sweden)

    B. C. Brightlin

    2016-05-01

    Full Text Available Abstract The nanocrystalline BaFe12O19 powders were obtained from citrate sol–gel combustion-derived powder upon annealing at 800–1100 °C, and explored their structural, micro-structural, optical and magnetic properties. The thermal decomposition of citrate sol–gel combustion product was verified by means of thermogravimetric and differential thermal analysis. Structural identification of the citrate sol–gel combustion powder and annealed samples were investigated by powder X-ray diffraction. Though the combustion product exhibits cubic spinel phase material, the annealed powder yields good quality nanocrystalline hexagonal BaFe12O19 phase materials. The thin plate-like flakes morphology with random particle sizes of ~100–200 nm with slightly agglomerated particles of BaFe12O19 phase is analyzed by high resolution scanning electron microscopy for the good quality annealed sample. Photoluminescence emission spectrum of BaFe12O19 material reveals broad emission peak at ~360 nm under the excitation wavelength of 270 nm. Interestingly, the near infrared relative reflectivity of the nanocrystalline BaFe12O19 materials obtained by citrate sol-gel synthesis method is higher than the nanocrystalline BaFe12O19 materials obtained by mechano-thermal and co-precipitation method. The present dark brown colored BaFe12O19 materials can be applied as a ceramic color pigment which includes several applications. The room temperature magnetic hysteresis loop of the annealed BaFe12O19 sample exhibits a ferromagnetic saturation magnetization, M s of 55.774 emu/g at 15 kOe.

  7. Influence of alloying and secondary annealing on anneal hardening ...

    Indian Academy of Sciences (India)

    Unknown

    Abstract. This paper reports results of investigation carried out on sintered copper alloys (Cu, 8 at%; Zn,. Ni, Al and Cu–Au with 4 at%Au). The alloys were subjected to cold rolling (30, 50 and 70%) and annealed isochronally up to recrystallization temperature. Changes in hardness and electrical conductivity were fol-.

  8. Influence of annealing temperature on the microstructure and magnetic properties of Ni/NiO core-shell nanowires

    Science.gov (United States)

    Xiang, Wenfeng; Liu, Yuan; Yao, Jiangfeng; Sun, Rui

    2018-03-01

    Ni/NiO core-shell nanowires (NWs) were synthesized by thermal annealing of Ni NWs and variations in the microstructure, surface morphology, and magnetic properties of the NWs as a function of annealing temperature were investigated. The results showed that the grain size and crystal quality of NiO increased with an increasing annealing temperature. Specially, the effect of annealing temperature was much greater than annealing time for the formation of Ni/NiO NWs during the oxidization process. The total weight gain of the Ni/NiO NWs continuously increased when the annealing temperature was lower than 400 °C and the annealing time was more than 2 h; however, the weight gain of the Ni/NiO NWs was almost constant after annealing for 40 min when the annealing temperature was higher than 500 °C. The thorns on the surface of the Ni/NiO NWs gradually passivated and magnetic properties declined when the annealing temperature was increased from 300 °C to 400 °C. Smooth Ni/NiO NWs with no magnetic properties were prepared when the annealing temperature was over 500 °C. The detail study regarding the formation and evolution of Ni/NiO NWs is of considerable value and may provide useful information regarding the choice of post-treatment parameters for different applications of Ni/NiO NWs.

  9. Sensitivity enhancement using annealed polymer optical fibre based sensors for pressure sensing applications

    DEFF Research Database (Denmark)

    Pospori, A.; Marques, C. A. F.; Saez-Rodriguez, D.

    2016-01-01

    Thermal annealing can be used to induce a permanent negative Bragg wavelength shift for polymer fibre grating sensors and it was originally used for multiplexing purposes. Recently, researchers showed that annealing can also provide additional benefits, such as strain and humidity sensitivity...... enhancement and augmented temperature operational range. The annealing process can change both the optical and mechanical properties of the fibre. In this paper, the annealing effects on the stress and force sensitivities of PMMA fibre Bragg grating sensors are investigated. The incentive...... for that investigation was an unexpected behaviour observed in an array of sensors which were used for liquid level monitoring. One sensor exhibited much lower pressure sensitivity and that was the only one that was not annealed. To further investigate the phenomenon, additional sensors were photo...

  10. Propagating self-sustained annealing of radiation-induced interstitial complexes

    International Nuclear Information System (INIS)

    Bokov, P M; Selyshchev, P A

    2016-01-01

    A propagating self-sustained annealing of radiation induced defects as a result of thermal-concentration instability is studied. The defects that are considered in the model are complexes. Each of them consists of one atom of impunity and of one interstitial atom. Crystal with defects has extra energy which is transformed into heat during defect annealing. Simulation of the auto-wave of annealing has been performed. The front and the speed of the auto-wave have been obtained. It is shown that annealing occurs in a narrow region of time and space. There are two kinds of such annealing behaviour. In the first case the speed of the auto-wave oscillates near its constant mean value and the front of temperature oscillates in a complex way. In the second case the speed of propagation is constant and fronts of temperature and concentration look like sigmoid functions. (paper)

  11. Effects of thermal treatment conditions on the phase formation and the morphological changes of sol-gel derived 0.67Pb(Mg1/3Nb2/3)O3-0.33PbTiO3 thin films

    International Nuclear Information System (INIS)

    Yang, Sun A; Han, Jin Kyu; Choi, Yong Chan; Bu, Sang Don

    2011-01-01

    We report the synthesis of Pb(Mg 1/3 Nb 2/3 )O 3 -PbTiO 3 (PMN-PT) thin films and the effects of thermal conditions on their surface morphologies and phase formation behaviors. The PMN-PT thin films were prepared by spin-coating PMN-PT sol-gel solutions on Pt/Ti/SiO 2 /Si substrates and subsequent thermal treatments including pyrolysis, annealing, and additional pre-annealing. We found that the surface morphologies and the formation of the perovskite phase were strongly affected by the final annealing temperature. The grain size of perovskite phase and the amount of the perovskite phase increased as the annealing temperature was increased from 550 to 800 .deg. C. We also found that the voids started to form on the surface of the film at an annealing temperature of 650 .deg. C and that their areas increased with increasing in annealing temperature. The void formation was found to depend on the time period of pyrolysis and on the pre-annealing process between pyrolysis and final annealing. Dense PMN-PT films with relatively high amounts of the perovskite phase were obtained when additional pre-annealing at 750 .deg. C for 5 min was performed.

  12. Radiation annealing of gallium arsenide implanted with sulphur

    CERN Document Server

    Ardyshev, V M

    2002-01-01

    Sulfur ions were implanted in a semi-insulating GaAs. Photon annealing (805 deg C/(10-12) s) and the thermal one (800 deg C/30 min) were conducted under SiO sub 2 -films coating obtained by different ways. Contents of GaAs components in films were determined from Rutherford backscattering spectra; concentration profiles of electrons were measured by the voltage-capacitance method. Diffusion of sulfur was shown to go in two directions - to the surface and into bulk of GaAs. The first process was induced by vacancies that had been formed near the surface of semiconductors during the dielectric coating. The coefficient of the bulk-diffusion and diffusion-to-surface of sulfur ions under photon annealing was twice as much as that under thermal one. The doping efficiency was also larger

  13. Radiation damage and annealing in plutonium tetrafluoride

    Energy Technology Data Exchange (ETDEWEB)

    McCoy, Kaylyn; Casella, Amanda; Sinkov, Sergey; Sweet, Lucas; McNamara, Bruce; Delegard, Calvin; Jevremovic, Tatjana

    2017-12-01

    Plutonium tetrafluoride that was separated prior to 1966 at the Hanford Site in Washington State was analyzed at the Pacific Northwest National Laboratory (PNNL) in 2015 and 2016. The plutonium tetrafluoride, as received, was an off-normal color and considering the age of the plutonium, there were questions about the condition of the material. These questions had to be answered in order to determine the suitability of the material for future use or long-term storage. Therefore, Thermogravimetric/Differential Thermal Analysis and X-ray Diffraction evaluations were conducted to determine the plutonium’s crystal structure, oxide content, and moisture content; these analyses reported that the plutonium was predominately amorphous and tetrafluoride, with an oxide content near ten percent. Freshly fluorinated plutonium tetrafluoride is known to be monoclinic. During the initial Thermogravimetric/Differential Thermal analyses, it was discovered that an exothermic event occurred within the material near 414°C. X-ray Diffraction analyses were conducted on the annealed tetrafluoride. The X-ray Diffraction analyses indicated that some degree of recrystallization occurred in conjunction with the 414°C event. The following commentary describes the series of Thermogravimetric/Differential Thermal and X-ray Diffraction analyses that were conducted as part of this investigation at PNNL, in collaboration with the University of Utah Nuclear Engineering Program.

  14. Laser annealing of sputter-deposited a-SiC and a-SiCxNy films

    Indian Academy of Sciences (India)

    Administrator

    To overcome this problem, thermal or laser anneal- ing is performed to induce crystallization of the films. (Fernandez-Ramos et al 2003). In recent years, Garcia and co-workers (2004) com- pared surface roughness, resistivity and X-ray diffraction pattern observed in a-Si and a-SiC films crystallized by laser annealing under ...

  15. Implantation of plasmonic nanoparticles in SiO{sub 2} by pulsed laser irradiation of gold films on SiO{sub x}-coated fused silica and subsequent thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Stolzenburg, H. [Laser-Laboratorium Göttingen, Hans-Adolf-Krebs-Weg 1, 37077 Göttingen (Germany); Peretzki, P.; Wang, N.; Seibt, M. [IV. Physikalisches Institut, Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen (Germany); Ihlemann, J., E-mail: juergen.ihlemann@llg-ev.de [Laser-Laboratorium Göttingen, Hans-Adolf-Krebs-Weg 1, 37077 Göttingen (Germany)

    2016-06-30

    Highlights: • Gold nanoparticles are implanted in glass by pulsed UV-laser irradiation. • Implantation of gold into SiO{sub x} and annealing leads to Au-particles in quartz glass. • TEM investigations reveal particles with 10–60 nm diameter in a depth of 40 nm. • Implanted particles show plasmon resonance at 540 nm. - Abstract: The pulsed UV-laser irradiation of thin noble metal films deposited on glass substrates leads to the incorporation of metal particles in the glass, if a sufficiently high laser fluence is applied. This process is called laser implantation. For the implantation of gold into pure fused silica, high laser fluences (∼1 J/cm{sup 2} at 193 nm laser wavelength) are required. Using a SiO{sub x} (x ≈ 1) coated SiO{sub 2}-substrate, the implantation of gold into this coating can be accomplished at significantly lower fluences starting from 0.2 J/cm{sup 2} (comparable to those used for standard glass). Particles with diameters in the range of 10–60 nm are implanted to a depth of about 40 nm as identified by transmission electron microscopy. An additional high temperature annealing step in air leads to the oxidation of SiO{sub x} to SiO{sub 2}, without influencing the depth distribution of particles significantly. Only superficial, weakly bound particles are released and can be wiped away. Absorption spectra show a characteristic plasmon resonance peak at 540 nm. Thus, pure silica glass (SiO{sub 2}) with near surface incorporated plasmonic particles can be fabricated with this method. Such material systems may be useful for example as robust substrates for surface enhanced Raman spectroscopy (SERS).

  16. Annealing behavior and selected applications of ion-implanted alloys

    International Nuclear Information System (INIS)

    Myers, S.M.

    Thermally activated processes cause ion-implanted metals to evolve from the initial state toward thermodynamic equilibrium. The degree of equilibration is strongly dependent upon temperature and is considered for three temperature regimes which are distinguished by the varying mobilities of interstitial and substitutional atoms. In addition, perturbations resulting from the irradiation environment are discussed. Examples are given of the use of implanted and annealed alloys in studies of diffusion, phase diagrams, and solute trapping

  17. Annealing effect in bulk heterojunction organic solar cells utilizing liquid crystalline phthalocyanine

    Science.gov (United States)

    Ohmori, Masashi; Fukui, Hitoshi; Dao, Quang-Duy; Kumada, Taishi; Fujii, Akihiko; Shimizu, Yo; Ozaki, Masanori

    2014-01-01

    The effect of annealing on bulk heterojunction solar cells utilizing the liquid crystalline phthalocyanine, 1,4,8,11,15,18,22,25-octahexylphthalocyanine (C6PcH2), fabricated using various solvents was studied. In the solar cells fabricated using chloroform, the power conversion efficiency was enhanced from 1.2 to 2.5% by thermal annealing at 75 °C, near the glass-transition temperature of the bulk heterojunction film. We discuss the effects of annealing on the photovoltaic properties by considering the exciton dissociation and carrier transport efficiencies obtained from photoluminescence spectra, X-ray diffraction measurement, and atomic force microscope observation.

  18. Proximity annealing of sulfur-implanted gallium arsenide using a strip heater

    International Nuclear Information System (INIS)

    Banerjee, S.; Baker, J.

    1985-01-01

    A graphite strip heater has been employed for rapid (-- 30 s) thermal annealing (RTA), at temperatures between 850 and 1150 0 C, of Cr-doped GaAs implanted with 120 keV 32 S + with doses between 10 13 and 10 15 cm -2 . In order to minimize the incongruent evaporation of As, proximity anneals were employed by protecting the implanted samples with GaAs cover pieces. RTA yields electrical activation and donor mobilities better than or comparable to furnace annealing, with less redistribution of the implanted S and background Cr. (author)

  19. Effect of vacuum annealing on evaporated pentacene thin films for memory device applications

    International Nuclear Information System (INIS)

    Gayathri, A.G.; Joseph, C.M.

    2016-01-01

    Graphical abstract: Switching of ITO/pentacene/Al thin films for different annealing temperatures. - Highlights: • Memory device performance in pentacene improved considerably with annealing. • ON/OFF ratio of the pentacene device increases due to annealing. • Threshold voltage reduces from 2.55 V to 1.35 V due to annealing. • Structure of pentacene thin films is also dependent on annealing temperature. - Abstract: Thin films of pentacene were deposited thermally onto glass substrates and annealed at 323 K, 373 K, 423 K, 473 K and 523 K in high vacuum. Effect of annealing on the morphological and structural properties of these films was studied. X-ray diffraction patterns confirmed the crystalline nature of the films. Electrical studies for the use as write once read many (WORM) memory devices were done for the vacuum deposited pentacene thin films on indium tin oxide coated glass. Due to annealing, a sharp increase in the ON/OFF ratio of current and a decrease in threshold voltage were observed at around 373 K. This device showed a stable switching with an ON/OFF current ratio as high as 10 9 and a switching threshold voltage of 1.35 V. The performance of the device degraded above 423 K due to the changes in the crystallinity of the film.

  20. Electrical behavior of amide functionalized graphene oxide and graphene oxide films annealed at different temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Rani, Sumita; Kumar, Mukesh, E-mail: kumarmukesh@gmail.com; Kumar, Dinesh; Sharma, Sumit

    2015-06-30

    Films of graphene oxide (GO) and amide functionalized graphene oxides (AGOs) were deposited on SiO{sub 2}/Si(100) by spin coating and were thermally annealed at different temperatures. Sheet resistance of GO and AGOs films was measured using four probe resistivity method. GO an insulator at room temperature, exhibits decrease in sheet resistance with increase in annealing temperature. However, AGOs' low sheet resistance (250.43 Ω) at room temperature further decreases to 39.26 Ω after annealing at 800 °C. It was observed that the sheet resistance of GO was more than AGOs up to 700 °C, but effect was reversed after annealing at higher temperature. At higher annealing temperatures the oxygen functionality reduces in GO and sheet resistance decreases. Sheet resistance was found to be annealing time dependent. Longer duration of annealing at a particular temperature results in decrease of sheet resistance. - Highlights: • Amide functionalized graphene oxides (AGOs) were synthesized at room temperature (RT). • AGO films have low sheet resistance at RT as compared to graphene oxide (GO). • Fast decrease in the sheet resistance of GO with annealing as compared to AGOs • AGOs were found to be highly dispersible in polar solvents.

  1. Direct Immersion Annealing of Block Copolymer Thin Films

    Science.gov (United States)

    Karim, Alamgir

    We demonstrate ordering of thin block copolymer (BCP) films via direct immersion annealing (DIA) at enhanced rate leading to stable morphologies. The BCP films are immersed in carefully selected mixtures of good and marginal solvents that can impart enhanced polymer mobility, while inhibiting film dissolution. DIA is compatible with roll-to-roll assembly manufacturing and has distinct advantages over conventional thermal annealing and batch processing solvent-vapor annealing methods. We identify three solvent composition-dependent BCP film ordering regimes in DIA for the weakly interacting polystyrene -poly(methyl methacrylate) (PS -PMMA) system: rapid short range order, optimal long-range order, and a film instability regime. Kinetic studies in the ``optimal long-range order'' processing regime as a function of temperature indicate a significant reduction of activation energy for BCP grain growth compared to oven annealing at conventional temperatures. An attractive feature of DIA is its robustness to ordering other BCP (e.g. PS-P2VP) and PS-PMMA systems exhibiting spherical, lamellar and cylindrical ordering. Inclusion of nanoparticles in these films at high concentrations and fast ordering kinetics study with neutron reflectivity and SANS will be discussed. This is (late) Contributed Talk Abstract for Dillon Medal Symposium at DPOLY - discussed with DPOLY Chair Dvora Perahia.

  2. Sintering and annealing effects on ZnO microstructure and thermoelectric properties

    International Nuclear Information System (INIS)

    Søndergaard, Martin; Bøjesen, Espen D.; Borup, Kasper A.; Christensen, Sebastian; Christensen, Mogens; Iversen, Bo B.

    2013-01-01

    The influence of different thermal treatments on zinc oxide has been investigated regarding the thermal diffusivity and structural properties of doped and undoped samples. ZnO powders having various grain sizes and morphologies, with or without aluminum doping, have been prepared under different temperatures by spark plasma sintering (SPS). The microstructural properties and thermal diffusivities of the prepared samples have been measured before and after annealing treatments in air at 800 °C. In undoped samples, the crystallite sizes increased after the annealing treatments, while it was retained in the Al-doped samples. The thermal diffusivities, microstrain and degree of preferred orientation were affected by the SPS temperature and the annealing; however, the general trends were retained after the annealing treatments. Lower maximum temperature yielded a lower degree of preferred orientation, less microstrain, higher density of grain boundaries, lower thermal diffusivities and, for Al-doped samples, lower electrical conductivity and a difference in zT-values from 0.2 to 0.3 at 800 °C. Calculations of the wavelengths and mean free paths of the phonons that contribute to the main part of the thermal conductivity have been conducted and reveal that nanostructures <12 nm are required to lower the thermal conductivity by quantum confinement

  3. A helium-based model for the effects of radiation damage annealing on helium diffusion kinetics in apatite

    Science.gov (United States)

    Willett, Chelsea D.; Fox, Matthew; Shuster, David L.

    2017-11-01

    Widely used to study surface processes and the development of topography through geologic time, (U-Th)/He thermochronometry in apatite depends on a quantitative description of the kinetics of 4He diffusion across a range of temperatures, timescales, and geologic scenarios. Empirical observations demonstrate that He diffusivity in apatite is not solely a function of temperature, but also depends on damage to the crystal structure from radioactive decay processes. Commonly-used models accounting for the influence of thermal annealing of radiation damage on He diffusivity assume the net effects evolve in proportion to the rate of fission track annealing, although the majority of radiation damage results from α-recoil. While existing models adequately quantify the net effects of damage annealing in many geologic scenarios, experimental work suggests different annealing rates for the two damage types. Here, we introduce an alpha-damage annealing model (ADAM) that is independent of fission track annealing kinetics, and directly quantifies the influence of thermal annealing on He diffusivity in apatite. We present an empirical fit to diffusion kinetics data and incorporate this fit into a model that tracks the competing effects of radiation damage accumulation and annealing on He diffusivity in apatite through geologic time. Using time-temperature paths to illustrate differences between models, we highlight the influence of damage annealing on data interpretation. In certain, but not all, geologic scenarios, the interpretation of low-temperature thermochronometric data can be strongly influenced by which model of radiation damage annealing is assumed. In particular, geologic scenarios involving 1-2 km of sedimentary burial are especially sensitive to the assumed rate of annealing and its influence on He diffusivity. In cases such as basement rocks in Grand Canyon and the Canadian Shield, (U-Th)/He ages predicted from the ADAM can differ by hundreds of Ma from those

  4. Simulated annealing model of acupuncture

    Science.gov (United States)

    Shang, Charles; Szu, Harold

    2015-05-01

    The growth control singularity model suggests that acupuncture points (acupoints) originate from organizers in embryogenesis. Organizers are singular points in growth control. Acupuncture can cause perturbation of a system with effects similar to simulated annealing. In clinical trial, the goal of a treatment is to relieve certain disorder which corresponds to reaching certain local optimum in simulated annealing. The self-organizing effect of the system is limited and related to the person's general health and age. Perturbation at acupoints can lead a stronger local excitation (analogous to higher annealing temperature) compared to perturbation at non-singular points (placebo control points). Such difference diminishes as the number of perturbed points increases due to the wider distribution of the limited self-organizing activity. This model explains the following facts from systematic reviews of acupuncture trials: 1. Properly chosen single acupoint treatment for certain disorder can lead to highly repeatable efficacy above placebo 2. When multiple acupoints are used, the result can be highly repeatable if the patients are relatively healthy and young but are usually mixed if the patients are old, frail and have multiple disorders at the same time as the number of local optima or comorbidities increases. 3. As number of acupoints used increases, the efficacy difference between sham and real acupuncture often diminishes. It predicted that the efficacy of acupuncture is negatively correlated to the disease chronicity, severity and patient's age. This is the first biological - physical model of acupuncture which can predict and guide clinical acupuncture research.

  5. Annealing effect in structural and electrical properties of sputtered Mo thin film

    Energy Technology Data Exchange (ETDEWEB)

    Chelvanathan, P.; Zakaria, Z. [Solar Energy Research Institute, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Yusoff, Y. [Department of Electrical, Electronic and System Engineering, FKAB, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Akhtaruzzaman, M. [Solar Energy Research Institute, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Alam, M.M. [Advanced Materials Research Chair, Chemistry Department, College of Sciences, King Saud University, Riyadh 11451 (Saudi Arabia); Alghoul, M.A.; Sopian, K. [Solar Energy Research Institute, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Amin, N., E-mail: nowshadamin@yahoo.com [Solar Energy Research Institute, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Department of Electrical, Electronic and System Engineering, FKAB, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Advanced Materials Research Chair, Chemistry Department, College of Sciences, King Saud University, Riyadh 11451 (Saudi Arabia)

    2015-04-15

    Highlights: • We deposited Mo thin film by DC-sputtering for solar cell back contact application. • We examined the changes in the film quality in terms of structural, and electrical upon vacuum thermal annealing. • Vacuum thermal annealing at different temperature changes the degree of preferred orientation of (1 1 0) and (2 1 1) significantly. • Correlation of structural and electrical parameters was carried out. - Abstract: In this study, the effects of vacuum annealing on the structural and electrical properties of DC-sputtered molybdenum (Mo) thin films have been investigated. Mo thin films were deposited by DC sputtering and subsequently subjected to vacuum annealing in a tube furnace from 350 to 500 °C. Films that were deposited with different temperatures showed good adhesion with soda lime glass substrate after “tape testing”. X-ray diffraction (XRD) spectra have indicated existence of (1 1 0) and (2 1 1) orientations. However, I(1 1 0)/I(2 1 1) peak intensity ratio decreased for all vacuum annealed Mo films compared to as-sputtered films indicating change of preferential orientation. This suggests vacuum annealing can be employed to tailor the Mo thin film atomic packing density of the plane parallel to the substrate. SEM images of surface morphology clearly show compact and dense triangular like grains for as-sputtered film, while annealed films at 350 °C, 400 °C and 450 °C indicate rice-like grains. Stony grains with less uniformity were detected for films annealed for 500 °C. Meanwhile, electrical resistivity is insensitive to the vacuum annealing condition as all films showed more or less same resistivity in the range of 3 × 10{sup −5}–6 × 10{sup −5} Ω cm.

  6. Partially Annealed Disorder and Collapse of Like-Charged Macroions

    Science.gov (United States)

    Mamasakhlisov, Yevgeni S.; Naji, Ali; Podgornik, Rudolf

    2008-11-01

    Charged systems with partially annealed charge disorder are investigated using field-theoretic and replica methods. Charge disorder is assumed to be confined to macroion surfaces surrounded by a cloud of mobile neutralizing counterions in an aqueous solvent. A general formalism is developed by assuming that the disorder is partially annealed (with purely annealed and purely quenched disorder included as special cases), i.e., we assume in general that the disorder undergoes a slow dynamics relative to fast-relaxing counterions making it possible thus to study the stationary-state properties of the system using methods similar to those available in equilibrium statistical mechanics. By focusing on the specific case of two planar surfaces of equal mean surface charge and disorder variance, it is shown that partial annealing of the quenched disorder leads to renormalization of the mean surface charge density and thus a reduction of the inter-plate repulsion on the mean-field or weak-coupling level. In the strong-coupling limit, charge disorder induces a long-range attraction resulting in a continuous disorder-driven collapse transition for the two surfaces as the disorder variance exceeds a threshold value. Disorder annealing further enhances the attraction and, in the limit of low screening, leads to a global attractive instability in the system.

  7. Enhancing quantum annealing performance for the molecular similarity problem

    Science.gov (United States)

    Hernandez, Maritza; Aramon, Maliheh

    2017-05-01

    Quantum annealing is a promising technique which leverages quantum mechanics to solve hard optimization problems. Considerable progress has been made in the development of a physical quantum annealer, motivating the study of methods to enhance the efficiency of such a solver. In this work, we present a quantum annealing approach to measure similarity among molecular structures. Implementing real-world problems on a quantum annealer is challenging due to hardware limitations such as sparse connectivity, intrinsic control error, and limited precision. In order to overcome the limited connectivity, a problem must be reformulated using minor-embedding techniques. Using a real data set, we investigate the performance of a quantum annealer in solving the molecular similarity problem. We provide experimental evidence that common practices for embedding can be replaced by new alternatives which mitigate some of the hardware limitations and enhance its performance. Common practices for embedding include minimizing either the number of qubits or the chain length and determining the strength of ferromagnetic couplers empirically. We show that current criteria for selecting an embedding do not improve the hardware's performance for the molecular similarity problem. Furthermore, we use a theoretical approach to determine the strength of ferromagnetic couplers. Such an approach removes the computational burden of the current empirical approaches and also results in hardware solutions that can benefit from simple local classical improvement. Although our results are limited to the problems considered here, they can be generalized to guide future benchmarking studies.

  8. Subsecond annealing of advanced materials annealing by lasers, flash lamps and swift heavy ions

    CERN Document Server

    Skorupa, Wolfgang

    2014-01-01

    This book examines thermal processing of elemental semiconductors and materials including nanostructures with novel optoelectronic, magnetic, and superconducting properties. Covers compound semiconductors, dielectric composites and organic materials.

  9. Insights into post-annealing and silver doping effects on the internal microstructure of ZnO nanoparticles through X-ray diffraction probe

    Science.gov (United States)

    Obeydavi, Ali; Dastafkan, Kamran; Rahimi, Mohammad; Ghadam Dezfouli, Mohammad Amin

    2017-07-01

    ZnO nanoparticles were synthesized via Pechini method at various post-annealing temperatures (400°, 500°, and 600 °C) and silver doping concentrations (Zn:Ag molar ratios of 30, 20, and 10). Multifarious microstructural features including crystallite size, size-strain based broadening, residual stress, preferential orientation, crystallinity degree, lattice parameters, unit cell variation, and stacking fault probability were surveyed through phase analysis, Williamson-Hall plot, texture coefficient and unit cell calculations. X-ray probing verified good crystallinity with a hexagonal close pack Wurtzite morphology. Williamson-Hall analysis exhibited distributions of crystallite size and microstrain as well as their contributions on the line broadening of the host ZnO and guest Ag phases upon annealing-doping treatments. Textural analysis revealed the alteration in anisotropic crystallinity of the host phase and transformation of the preferred directions, (100) and (101), as function of annealing-doping processes. Besides, while guest Ag phase was shown to be polycrystalline with randomly orientated crystals at moderate concentration with respect to thermal treatment, preferential orientation went through a major change, (220) to (111), with increment in Ag loadings. Under identical synthetic conditions, the distinction in the lattice constants and unit cell variation between pure and doped ZnO nanoparticles was enforced and results verified major impressionability via annealing and doping factors.

  10. Influence of annealing on microstructure and physical properties of isotactic polypropylene/calcium carbonate composites with {beta}-phase nucleating agent

    Energy Technology Data Exchange (ETDEWEB)

    Han Liang; Li Xiaoxi; Li Yanli; Huang Ting [Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China); Wang Yong, E-mail: yongwang1976@163.com [Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China); Wu Jun; Xiang, Fangming [Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China)

    2010-05-25

    As a part of serial work about the application of nucleating agent (NA) in polymer blends or polymer composites, a {beta}-phase NA aryl amides compound (TMB-5) had been introduced into isotactic polypropylene/calcium carbonate (iPP/CaCO{sub 3}) composites in this work. The specimens were annealed for 12 h at different temperatures (90-150 deg. C) and at 130 deg. C for different durations (3-12 h). The variations of microstructures during the annealing process were investigated using wide angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA). The physical properties, including fracture toughness, stiffness and thermal properties, were measured, too. The results indicate that the decreased numbers of chain segments in amorphous region, which is easily triggered by the secondary crystallization during the annealing process, is beneficial to the improvement of toughness through promoting the lamellae to slip or elongate along the impact direction and inducing the intense plastic deformation during the fracture toughness. Further results show that improved stiffness and largely enhanced heat distortion temperature are easily achieved due to the increased fraction of crystalline component and the improved crystalline structure obtained during the annealing process. Anyway, this work proposed a simple way to achieve iPP/CaCO{sub 3} composites with high performance at very low load of CaCO{sub 3}.

  11. Chaotic Multiquenching Annealing Applied to the Protein Folding Problem

    Directory of Open Access Journals (Sweden)

    Juan Frausto-Solis

    2014-01-01

    Full Text Available The Chaotic Multiquenching Annealing algorithm (CMQA is proposed. CMQA is a new algorithm, which is applied to protein folding problem (PFP. This algorithm is divided into three phases: (i multiquenching phase (MQP, (ii annealing phase (AP, and (iii dynamical equilibrium phase (DEP. MQP enforces several stages of quick quenching processes that include chaotic functions. The chaotic functions can increase the exploration potential of solutions space of PFP. AP phase implements a simulated annealing algorithm (SA with an exponential cooling function. MQP and AP are delimited by different ranges of temperatures; MQP is applied for a range of temperatures which goes from extremely high values to very high values; AP searches for solutions in a range of temperatures from high values to extremely low values. DEP phase finds the equilibrium in a dynamic way by applying least squares method. CMQA is tested with several instances of PFP.

  12. Modeling of the transient interstitial diffusion of implanted atoms during low-temperature annealing of silicon substrates

    International Nuclear Information System (INIS)

    Velichko, O.I.; Kavaliova, A.P.

    2012-01-01

    It has been shown that many of the phenomena related to the formation of “tails” in the low-concentration region of ion-implanted impurity distribution are due to the anomalous diffusion of nonequilibrium impurity interstitials. These phenomena include boron implantation in preamorphized silicon, a “hot” implantation of indium ions, annealing of ion-implanted layers et cetera. In particular, to verify this microscopic mechanism, a simulation of boron redistribution during low-temperature annealing of ion-implanted layers has been carried out under different conditions of transient enhanced diffusion suppression. Due to the good agreement with the experimental data, the values of the average migration length of nonequilibrium impurity interstitials have been obtained. It has been shown that for boron implanted into a silicon layer preamorphized by germanium ions the average migration length of impurity interstitials at the annealing temperature of 800 °C can be reduced from 11 nm to approximately 6 nm due to additional implantation of nitrogen. The further shortening of the average migration length is observed if the processing temperature is reduced to 750 °C. It is also found that for implantation of BF 2 ions into silicon crystal, the value of the average migration length of boron interstitials is equal to 7.2 nm for thermal treatment at a temperature of 800 °C.

  13. A theoretical comparison of evolutionary algorithms and simulated annealing

    Energy Technology Data Exchange (ETDEWEB)

    Hart, W.E.

    1995-08-28

    This paper theoretically compares the performance of simulated annealing and evolutionary algorithms. Our main result is that under mild conditions a wide variety of evolutionary algorithms can be shown to have greater performance than simulated annealing after a sufficiently large number of function evaluations. This class of EAs includes variants of evolutionary strategie and evolutionary programming, the canonical genetic algorithm, as well as a variety of genetic algorithms that have been applied to combinatorial optimization problems. The proof of this result is based on a performance analysis of a very general class of stochastic optimization algorithms, which has implications for the performance of a variety of other optimization algorithm.

  14. Accessing Forbidden Glass Regimes through High-Pressure Sub-Tg Annealing

    Science.gov (United States)

    Svenson, Mouritz N.; Mauro, John C.; Rzoska, Sylwester J.; Bockowski, Michal; Smedskjaer, Morten M.

    2017-04-01

    Density and hardness of glasses are known to increase upon both compression at the glass transition temperature (Tg) and ambient pressure sub-Tg annealing. However, a serial combination of the two methods does not result in higher density and hardness, since the effect of compression is countered by subsequent annealing and vice versa. In this study, we circumvent this by introducing a novel treatment protocol that enables the preparation of high-density, high-hardness bulk aluminosilicate glasses. This is done by first compressing a sodium-magnesium aluminosilicate glass at 1 GPa at Tg, followed by sub-Tg annealing in-situ at 1 GPa. Through density, hardness, and heat capacity measurements, we demonstrate that the effects of hot compression and sub-Tg annealing can be combined to access a “forbidden glass” regime that is inaccessible through thermal history or pressure history variation alone. We also study the relaxation behavior of the densified samples during subsequent ambient pressure sub-Tg annealing. Density and hardness are found to relax and approach their ambient condition values upon annealing, but the difference in relaxation time of density and hardness, which is usually observed for hot compressed glasses, vanishes for samples previously subjected to high-pressure sub-Tg annealing. This confirms the unique configurational state of these glasses.

  15. An Alternative Approach for Improving Performance of Organic Photovoltaics by Light-Enhanced Annealing

    Directory of Open Access Journals (Sweden)

    En-Ping Yao

    2014-01-01

    Full Text Available This work proposes an approach for improving the performance of poly(3-hexylthiophene (P3HT- based organic photovoltaics (OPVs. P3HT-based bulk heterojunction (BHJ film can absorb the energy from 532 nm laser light and be transformed into favorable morphology. A combination of traditional thermal annealing and laser annealing improved device performance, with a slight increase in fill factor and a significant improvement in short-circuit current density. Better crystallization and a higher degree of molecular order in the thermal/laser coannealed P3HT-based BHJ film were observed through X-ray diffraction and Raman spectroscopy.

  16. SANS examination of irradiated RPV steel welds during in-situ annealing

    Energy Technology Data Exchange (ETDEWEB)

    Boothby, R.M. [National Nuclear Laboratory, B168 Harwell Campus, Didcot, Oxon. OX11 0QT (United Kingdom); Hyde, J.M., E-mail: jonathan.m.hyde@nnl.co.uk [National Nuclear Laboratory, B168 Harwell Campus, Didcot, Oxon. OX11 0QT (United Kingdom); Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Swan, H. [National Nuclear Laboratory, B168 Harwell Campus, Didcot, Oxon. OX11 0QT (United Kingdom); Parfitt, D.; Wilford, K. [Rolls-Royce plc, P.O. Box 2000, Derby DE21 7XX (United Kingdom); Lindner, P. [Institut Laue-Langevin, 71 avenue des Martyrs, CS20156, 38042 Grenoble CEDEX 9 (France)

    2015-06-15

    An in-situ annealing experiment was performed using SANS measurements to examine the distribution and thermal stability of irradiation-induced solute clusters in RPV steel welds. Samples were sequentially annealed for 30 min at ∼50 °C intervals in the temperature range 295–497 °C. A methodology was developed to correct the observed data to allow for increased thermal diffuse scattering during annealing which enabled analysis of the changes in coherent scattering in isolation. Results for a low-Ni weld irradiated at low temperature showed apparent decreases in the volume fraction of solute clusters during annealing. However the cluster size was unaffected and these results could have arisen from reduced scattering contrast due to compositional changes, rather than cluster dissolution. A similarly irradiated high-Ni weld exhibited cluster coarsening at high annealing temperatures. Samples of both welds irradiated at a higher temperature were relatively unaffected by annealing except at high temperatures where some shrinkage, indicative of cluster dissolution, occurred.

  17. Effect of annealing on the compositional modulation of InAlAsSb

    Energy Technology Data Exchange (ETDEWEB)

    Baladés, N., E-mail: nuria.balades@uca.es [INNANOMAT group, Departamento de Ciencia de los Materiales e I. M. y Q. I., Instituto Universitario de Investigación en Microscopía Electrónica y Materiales (IMEYMAT), CEIMAR, Universidad de Cádiz, 11510 Puerto Real, Cádiz (Spain); Sales, D.L.; Herrera, M.; Delgado, F.J. [INNANOMAT group, Departamento de Ciencia de los Materiales e I. M. y Q. I., Instituto Universitario de Investigación en Microscopía Electrónica y Materiales (IMEYMAT), CEIMAR, Universidad de Cádiz, 11510 Puerto Real, Cádiz (Spain); González, M. [U.S Naval Research Laboratory, 4555 Overlook Ave. SW, Washington D.C. 20375 (United States); Sotera Defense Solutions, 430 National Business Pkwy # 100, Annapolis Junction, MD 20701 (United States); Clark, K.; Pinsunkajana, P. [Intelligent Epitaxy Technology, Inc. Richardson, TX, 75801 (United States); Hoven, N.; Hubbard, S. [Rochester Institute of Technology, 85 Lomb Memorial Drive, Rochester, NY 14623 (United States); Tomasulo, S.; Walters, J.R. [U.S Naval Research Laboratory, 4555 Overlook Ave. SW, Washington D.C. 20375 (United States); Molina, S.I. [INNANOMAT group, Departamento de Ciencia de los Materiales e I. M. y Q. I., Instituto Universitario de Investigación en Microscopía Electrónica y Materiales (IMEYMAT), CEIMAR, Universidad de Cádiz, 11510 Puerto Real, Cádiz (Spain)

    2017-02-15

    Highlights: • A post-growth annealing under As overpressure over 500 °C for several minutes induces a blue-shift in the InAlAsSb emission. • TEM analysis evidences that the small compositional fluctuations of the as-grown samples disappear after being annealed. • Annealing stimulates atomic diffusion of the quaternary, homogenizing their constituents and enhancing structural quality. - Abstract: The effect of a post-growth thermal treatment in two different heterostructures with InAlAsSb as the top layer grown by molecular beam epitaxy lattice-matched to InP, have been studied by diffraction contrast transmission electron microscopy (TEM). This novel top cell layer material with application in ultra-high efficiency solar cells were grown on (001) InP substrate with or without an InGaAs buffer layer. Initial photoluminescence (PL) measurements revealed deviations from their predicted bandgap, suggesting non-random atomic distribution of the quaternary layer. Then, a thermal annealing was performed at different temperatures and times. The effect on the structure of the InAlAsSb active layer caused by the new arrangement of layers and the post-growth annealing treatments has been reported. Our results show that the small compositional fluctuations of the as-grown heterostructures disappear after being annealed, and the bandgap energy correspondingly increases towards the predicted value.

  18. Quantum annealing for combinatorial clustering

    Science.gov (United States)

    Kumar, Vaibhaw; Bass, Gideon; Tomlin, Casey; Dulny, Joseph

    2018-02-01

    Clustering is a powerful machine learning technique that groups "similar" data points based on their characteristics. Many clustering algorithms work by approximating the minimization of an objective function, namely the sum of within-the-cluster distances between points. The straightforward approach involves examining all the possible assignments of points to each of the clusters. This approach guarantees the solution will be a global minimum; however, the number of possible assignments scales quickly with the number of data points and becomes computationally intractable even for very small datasets. In order to circumvent this issue, cost function minima are found using popular local search-based heuristic approaches such as k-means and hierarchical clustering. Due to their greedy nature, such techniques do not guarantee that a global minimum will be found and can lead to sub-optimal clustering assignments. Other classes of global search-based techniques, such as simulated annealing, tabu search, and genetic algorithms, may offer better quality results but can be too time-consuming to implement. In this work, we describe how quantum annealing can be used to carry out clustering. We map the clustering objective to a quadratic binary optimization problem and discuss two clustering algorithms which are then implemented on commercially available quantum annealing hardware, as well as on a purely classical solver "qbsolv." The first algorithm assigns N data points to K clusters, and the second one can be used to perform binary clustering in a hierarchical manner. We present our results in the form of benchmarks against well-known k-means clustering and discuss the advantages and disadvantages of the proposed techniques.

  19. Loviisa Unit One: Annealing - healing

    Energy Technology Data Exchange (ETDEWEB)

    Kohopaeae, J.; Virsu, R. [ed.; Henriksson, A. [ed.

    1997-11-01

    Unit 1 of the Loviisa nuclear powerplant was annealed in connection with the refuelling outage in the summer of 1996. This type of heat treatment restored the toughness properties of the pressure vessel weld, which had been embrittled be neutron radiation, so that it is almost equivalent to a new weld. The treatment itself was an ordinary metallurgical procedure that took only a few days. But the material studies that preceded it began over fifteen years ago and have put IVO at the forefront of world-wide expertise in the area of radiation embrittlement

  20. Dehydration, with and without heat, in kangaroos from mesic and arid habitats: different thermal responses including varying patterns in heterothermy in the field and laboratory.

    Science.gov (United States)

    Dawson, Terence J; Blaney, Cyntina E; McCarron, Hugh C K; Maloney, Shane K

    2007-10-01

    Field data showing the daily patterns in body temperature (T(b)) of kangaroos in hot, arid conditions, with and without water, indicate the use of adaptive heterothermy, i.e. large variation in T(b). However, daily T(b) variation was greater in the Eastern Grey Kangaroo (Macropus giganteus), a species of mesic origin, than in the desert-adapted Red Kangaroo (Macropus rufus). The nature of such responses was studied by an examination of their thermal adjustments to dehydration in thermoneutral temperatures (25 degrees C) and at high temperature (45 degrees C) via the use of tame, habituated animals in a climate chamber. At the same level of dehydration M. rufus was less impacted, in that its T(b) changed less than that for M. giganteus while it evaporated significantly less water. At a T(a) of 45 degrees C with water restriction T(b) reached 38.9 +/- 0.3 degrees C in M. rufus compared with 40.2 +/- 0.4 degrees C for M. giganteus. The ability of M. rufus to reduce dry conductance in the heat while dehydrated was central to its superior thermal control. While M. giganteus showed more heterothermy, i.e. its T(b) varied more, this seemed due to a lower tolerance of dehydration in concert with a strong thermal challenge. The benefits of heterothermy to M. giganteus were also limited because of thermal (Q(10)) effects on metabolic heat production and evaporative heat loss. The impacts of T(b) on heat production were such that low morning T(b)'s seen in the field may be associated with energy saving, as well as water saving. Kangaroos respond to dehydration and heat similarly to many ungulates, and it is apparent that the accepted notions about adaptive heterothermy in large desert mammals may need revisiting.

  1. Effect of cryo-rolling and annealing on microstructure and properties of commercially pure aluminium

    Energy Technology Data Exchange (ETDEWEB)

    Rangaraju, Nikhil [Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai 600 036 (India); Raghuram, T. [Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai 600 036 (India); Krishna, B. Vamsi [Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai 600 036 (India)]. E-mail: vamsi23@yahoo.com; Rao, K. Prasad [Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai 600 036 (India); Venugopal, P. [Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai 600 036 (India)

    2005-05-25

    Influence of cryo-rolling reduction and annealing of commercially pure (CP) Al is evaluated in four aspects: microstructure, mechanical properties, electrical conductivity and general corrosion. It is shown that by selecting optimal cryo-rolling reduction and subsequent annealing condition result in ultrafine grains in CP Al with good combination of high strength and ductility. Electrical conductivity of the cryo-rolled samples decreased due to increased number of the electron scattering centers (lattice defects and grain boundary area). However, optimization of cryo-rolling and annealing treatment could restore the conductivity coupled with high strength in CP Al. Corrosion behaviour of cryo-rolled CP Al improved after annealing treatment. High dissolution rate and low thermal stability of the ultrafine grain structure could override the anticipated advantage of uniform corrosion in ultrafine grain CP Al.

  2. Simulated annealing with constant thermodynamic speed

    International Nuclear Information System (INIS)

    Salamon, P.; Ruppeiner, G.; Liao, L.; Pedersen, J.

    1987-01-01

    Arguments are presented to the effect that the optimal annealing schedule for simulated annealing proceeds with constant thermodynamic speed, i.e., with dT/dt = -(v T)/(ε-√C), where T is the temperature, ε- is the relaxation time, C ist the heat capacity, t is the time, and v is the thermodynamic speed. Experimental results consistent with this conjecture are presented from simulated annealing on graph partitioning problems. (orig.)

  3. Keystream Generator Based On Simulated Annealing

    Directory of Open Access Journals (Sweden)

    Ayad A. Abdulsalam

    2011-01-01

    Full Text Available Advances in the design of keystream generator using heuristic techniques are reported. A simulated annealing algorithm for generating random keystream with large complexity is presented. Simulated annealing technique is adapted to locate these requirements. The definitions for some cryptographic properties are generalized, providing a measure suitable for use as an objective function in a simulated annealing algorithm, seeking randomness that satisfy both correlation immunity and the large linear complexity. Results are presented demonstrating the effectiveness of the method.

  4. Influence of Different Annealing Conditions on Optical and Electrical Properties of Sn Doped ZnO Thin Films

    Directory of Open Access Journals (Sweden)

    LIU Tao

    2017-08-01

    Full Text Available Sn doped ZnO thin films(SZO was prepared on glasses by sol-gel method.The influence of six kinds of annealing conditions,including air annealing,low vacuum annealing,high vacuum annealing,N2 annealing,triple high vacuum annealing,cycle annealing on the crystal structure, optical and electrical properties of the SZO film was studied.The results show that all the SZO samples show preferential orientation along the c-axis.The SZO thin films has the optimum crystal structure and electrical property on the high vacuum annealing conditions.The minimum resistivity of the film is 5.4×10-2Ω·cm.The average visible transmittance of SZO thin film is above 85%.The photoluminescence peaks at 390nm and 440nm is observed in all the samples (the excitation wavelength is set at 325nm.The intensity of the peak at 440nm is enhanced significantly on air annealing,N2 annealing and low vacuum annealing.

  5. Semantic search via concept annealing

    Science.gov (United States)

    Dunkelberger, Kirk A.

    2007-04-01

    Annealing, in metallurgy and materials science, is a heat treatment wherein the microstructure of a material is altered, causing changes in its properties such as strength and hardness. We define concept annealing as a lexical, syntactic, and semantic expansion capability (the removal of defects and the internal stresses that cause term- and phrase-based search failure) coupled with a directed contraction capability (semantically-related terms, queries, and concepts nucleate and grow to replace those originally deformed by internal stresses). These two capabilities are tied together in a control loop mediated by the information retrieval precision and recall metrics coupled with intuition provided by the operator. The specific representations developed have been targeted at facilitating highly efficient and effective semantic indexing and searching. This new generation of Find capability enables additional processing (i.e. all-source tracking, relationship extraction, and total system resource management) at rates, precisions, and accuracies previously considered infeasible. In a recent experiment, an order magnitude reduction in time to actionable intelligence and nearly three orderss magnitude reduction in false alarm rate was achieved.

  6. Neutron flux and annealing effects on irradiation hardening of RPV materials

    Science.gov (United States)

    Chaouadi, R.; Gérard, R.

    2011-11-01

    This paper aims to examine an eventual effect of neutron flux, sometimes referred to as dose rate effect, on irradiation hardening of a typical A533B reactor pressure vessel steel. Tensile tests on both low flux (reactor surveillance data) and high flux (BR2 reactor) were performed in a large fluence range. The obtained results indicate two features. First, the surveillance data exhibit a constant (˜90 MPa) higher yield strength than the high flux data. However, this difference cannot be explained from a flux effect but most probably from differences in the initial tensile properties. The hardening kinetic of both low and high flux is the same. Annealing at low temperature, 345 °C/40 h, to eventually reveal unstable matrix damage did not affect both BR2 and surveillance specimens. This is confirmed by other annealing experimental data including both tensile and hardness measurements and tensile data on A508 forging and weld. It is suggested that the absence of flux effect on the tensile properties while different radiation-induced microstructures can be attributed to thermal ageing effects.

  7. [Effect of annealing pressure on P3HT : PCBM nanoscale morphology and photovoltaic properties].

    Science.gov (United States)

    Li, Chang; Xue, Wei; Zhang, Ting; Zhao, Su-ling

    2015-01-01

    The considerable performance enhancement of P3HT-based solar cell after thermal annealing can be attributed to the thermodynamically driven partial crystallization and phase segregation of each component. In the present work, thermal annealing was executed by delivering P3HT : PCBM blend films onto the preheated susceptor in a PECVD chamber filled with high purity nitrogen gas. The pressure of inner chamber could be set steadily and precisely in the range of 1 to 1 850 mTorr at 150 °C. It was found that the phase segregation scale of two components was tuned to a certain extent by varying the annealing pressure, whereas the polymer crystallinity was slightly affected. According to the pressure settings, polymer solar cells (PSCs) were fabricated in the following structure: ITO/PEDOT : PSS/P3HT : PCBM/Al. All of the device parameters exhibited the similar trend--an initial increase followed by a decrease, and reached a peak at 1500 mTorr with successive increase in annealing setting pressure. PSC annealed under 1 500 mTorr shows overall high performances with the power conversion efficiency up to 3. 56%. The UV-Vis absorption spectra of annealed blend films shows that the vibronic absorption peaks (shoulders) at 510, 550 and 600 nm became more pronounced under higher setting pressure, which is attributed to better crystalline P3HT with increased π-π stacking of polymer molecules. The AFM results further suggest that high annealing pressure (>1000 mTorr) promoted the domain formations of P3HT or PCBM; moreover, a moderate phase segregation, as a result of an appropriate annealing pressure (1500 mTorr), facilitates polymer crystallization which ensures the high charge (hole) mobility and consequently increased short-circuit current and fill factor.

  8. Fracture behaviors of isotactic polypropylene/poly(ethylene oxide) blends: Effect of annealing

    Energy Technology Data Exchange (ETDEWEB)

    Wu Haiyan; Li Xiaoxi; Wang Yonghong; Wu Jun; Huang Ting [Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China); Wang Yong, E-mail: yongwang1976@163.com [Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China)

    2011-10-15

    Highlights: {yields} Immiscible polypropylene/poly(ethylene oxide) was annealed at different temperatures (50-160 deg. C) for 12 h and at 100 deg. C for different durations (12-96 h). {yields} Fracture behaviors of the annealed samples were systematically investigated by means of various measurements. {yields} In a range of annealing temperature (100-140 deg. C), largely improved fracture resistance was observed. {yields} Annealing treatment is favorable for the improvement of the storage modulus of the immiscible polymer blend. - Abstract: As a part of serial work about the toughening of isotactic polypropylene (iPP) during annealing treatment, this work reports the effect of annealing on fracture behaviors of iPP blend with a little of poly(ethylene oxide) (PEO). Injection-molded bars of an iPP/PEO blend were annealed at different temperatures (50-160 deg. C) for 12 h and at 100 deg. C for different durations (12-96 h). The fracture behaviors of the annealed samples, including notched Izod impact fracture, universal tensile fracture, and single-edge notched tensile (SENT) fracture, were comparatively investigated to establish the role of annealing in improving the fracture resistance of the sample. The results showed that the annealing treatment greatly influences the fracture resistance of the blend. The impact-fractured surface morphologies were characterized by scanning electron microscope (SEM) to clarify the possible mechanisms for the improvement of the fracture resistance. It was proposed that, the excellent fracture resistance of iPP with a minor phase of which exhibits relatively low melting temperature can be easily achieved through the simple annealing treatment, even if the minor phase is immiscible with iPP.

  9. Quantum annealing versus classical machine learning applied to a simplified computational biology problem

    Science.gov (United States)

    Li, Richard Y.; Di Felice, Rosa; Rohs, Remo; Lidar, Daniel A.

    2018-01-01

    Transcription factors regulate gene expression, but how these proteins recognize and specifically bind to their DNA targets is still debated. Machine learning models are effective means to reveal interaction mechanisms. Here we studied the ability of a quantum machine learning approach to predict binding specificity. Using simplified datasets of a small number of DNA sequences derived from actual binding affinity experiments, we trained a commercially available quantum annealer to classify and rank transcription factor binding. The results were compared to state-of-the-art classical approaches for the same simplified datasets, including simulated annealing, simulated quantum annealing, multiple linear regression, LASSO, and extreme gradient boosting. Despite technological limitations, we find a slight advantage in classification performance and nearly equal ranking performance using the quantum annealer for these fairly small training data sets. Thus, we propose that quantum annealing might be an effective method to implement machine learning for certain computational biology problems. PMID:29652405

  10. Effect of High Temperature Annealing on Conduction-Type ZnO Films Prepared by Direct-Current Magnetron Sputtering

    International Nuclear Information System (INIS)

    Sun Li-Jie; He Dong-Kai; Xu Xiao-Qiu; Zhong Ze; Wu Xiao-Peng; Lin Bi-Xia; Fu Zhu-Xi

    2010-01-01

    We experimentally find that the ZnO thin films deposited by dc-magnetron sputtering have different conduction types after annealing at high temperature in different ambient. Hall measurements show that ZnO films annealed at 1100°C in N 2 and in O 2 ambient become n-type and p-type, respectively. This is due to the generation of different intrinsic defects by annealing in different ambient. X-ray photoelectron spectroscopy and photolumi-nescence measurements indicate that zinc interstitial becomes a main defects after annealing at 1100°C in N 2 ambient, and these defects play an important role for n-type conductivity of ZnO. While the ZnO films annealed at 1100°C in O 2 ambient, the oxygen antisite contributes ZnO films to p-type. (condensed matter: structure, mechanical and thermal properties)

  11. Effect of annealing temperature on the mechanical properties of Zircaloy-4 cladding

    International Nuclear Information System (INIS)

    Beauregard, R.J.; Clevinger, G.S.; Murty, K.L.

    1977-01-01

    The mechanical properties of Zircaloy cladding materials are sensitive to those fabrication variables which have an effect on the preferred crystallographic orientation or texture of the finished tube. The effect of one such variable, the final annealing temperature, on various mechanical properties is examined using tube reduced Zircaloy-4 fuel rod cladding annealed at temperatures from 905F to 1060F. This temperature range provides cladding with varying degrees of recrystallization including full recrystallization. The burst strength of the cladding at 650F decreased with the annealing temperature reaching a saturation value at approximately 1000F. The total circumferential elongation increased with the annealing temperature reaching a maximum at approximately 1000F and decreasing at higher temperatures. Hoop creep characteristics of Zircaloy cladding were studied as a function of the annealing temperature using closed-end internal pressurization tests at 750F and hoop stresses of 10, 15, 20 and 25 ksi. The effect of annealing temperature on the room temperature mechanical anisotropy parameters, R and P, was studied. The R-parameter was essentially independent of the annealing temperature while the P-parameter increased with annealing temperature. The mechanical anisotropy parameters were also studied as a function of the test temperature from ambient to approximately 800F using continuously monitored high precision extensometry. (Auth.)

  12. Synthesis and characterization of nanocrystalline vanadium oxide thin films: electrochemical behavior by annealing in different atmosphere

    Science.gov (United States)

    Asiabar, M. Amiri; Mohaghegh, Z.; Ghodsi, F. E.

    2018-01-01

    Nanocrystalline vanadium oxide thin films were prepared using sol-gel dip-coating technique. The effect of heat treatment in different environment including air, N2, Ar, and O2 gas on the structural, optical, electrical, and electrochemical properties of nanocrystalline vanadium oxide thin films were investigated. The results indicated that the calculated average crystallite size was reduced by annealing in Ar environment. Scanning electron microscopy (SEM) images showed layered morphology on the surface of the film annealed in air atmosphere, whereas the film annealed under Ar and N2 ambient revealed granular and wrinkle morphology, respectively. This morphology altered to rather smooth surface by annealing in O2 environment. The optical bandgap of the films were found to be 1.75, 1.84, 2.08, and 2.10 eV annealed in air, O2, N2, and Ar environment, respectively. It was observed that the films annealed under Ar and N2 ambient had low resistivity ( 0.2 Ω cm) and high carrier concentration, while the film annealed in nitrogen environment showed higher mobility of charge carrier. The electrochemical measurements showed that annealing under N2 ambient improved the intercalation of Li ions, leading a higher interfacial capacitance of 19.18 mF Cm-2, and decreased the charge transfer resistance due to surface defects created by heat treatment in nitrogen environment.

  13. Annealed Demon Algorithms Solving the Environmental / Economic Dispatch Problem

    Directory of Open Access Journals (Sweden)

    Aristidis VLACHOS

    2013-06-01

    Full Text Available This paper presents an efficient and reliable Annealed Demon (AD algorithm for the Environmental/Economic Dispatch (EEB problem. The EED problem is a multi-objective non-linear optimization problem with constraints. This problem is one of the fundamentals issues in power system operation. The system of generation associates thermal generators and emissions which involves sulphur oxides (SO2 and nitrogen oxides (NOx. The aim is to minimize total fuel cost of the system and control emission. The proposed AD algorithm is applied for EED of a simple power system.

  14. Development and anneal of radiation damage in salt

    International Nuclear Information System (INIS)

    Garcia Celma, A.; Donker, H.; Soppe, W.J.; Miralles, L.

    1993-12-01

    Laboratory gamma-irradiations at a constant temperature (100 C) were carried out in two sorts of experiments, one at variable and another at approximately constant dose rates. The damage developed during irradiation was analyzed by thermal analysis, microstructural analysis and small angle neutron scattering. The results were compared with the yields of the Jain-Lidiard model for each experiment. Experiments at a constant dose rate were planned to obtain information on radiation damage development and anneal in conditions as near as possible to those of radioactive waste repository concepts. For this reason the dose rates were kept low. (orig./DG)

  15. Temperature-dependent thermal properties of Ru/C multilayers.

    Science.gov (United States)

    Yan, Shuai; Jiang, Hui; Wang, Hua; He, Yan; Li, Aiguo; Zheng, Yi; Dong, Zhaohui; Tian, Naxi

    2017-09-01

    Multilayers made of Ru/C are the most promising candidates when working in the energy region 8-20 keV. The stability of its thermal properties, including thermal expansion and thermal conduction, needs to be considered for monochromator or focusing components. Ru/C multilayers with periodic thicknesses of 3, 4 and 5 nm were investigated in situ by grazing-incidence X-ray reflectometry and diffuse scattering in order to study their thermal expansion characteristics as a function of annealing temperature up to 400°C. The thermal conductivity of multilayers with the same structure was also measured by the transient hot-wire method and compared with bulk values.

  16. Positron annihilation characteristics of ODS and non-ODS EUROFER isochronally annealed

    International Nuclear Information System (INIS)

    Ortega, Y.; Castro, V. de; Monge, M.A.; Munoz, A.; Leguey, T.; Pareja, R.

    2008-01-01

    Yttrium oxide dispersion strengthened (ODS) and non-ODS EUROFER produced by mechanical alloying and hot isostatic pressing have been subjected to isochronal annealing up to 1523 K, and the evolution of the open-volume defects and their thermal stability have been investigated using positron lifetime and coincidence Doppler broadening (CDB) techniques. Transmission electron microscopy (TEM) observations have also been performed on the studied samples to verify the characteristics of the surviving defects after annealing at 1523 K. The CDB spectra of ODS EUROFER exhibit a characteristic signature that is attributed to positron annihilation in Ar-decorated cavities at the oxide particle/matrix interfaces. The variation of the positron annihilation parameters with the annealing temperature shows three stages: up to 623 K, between 823 and 1323 K, and above 1323 K. Three-dimensional vacancy clusters, or voids, are detected in either materials in as-HIPed condition and after annealing at T ≤ 623 K. In the temperature range 823-1323 K, these voids' growth and nucleation and the growth of other new species of voids take place. Above 1323 K, some unstable cavities start to anneal out, and cavities associated to oxide particles and other small precipitates survive to annealing at 1523 K. The TEM observations and the positron annihilation results indicate that these cavities should be decorated with Ar atoms absorbed during the mechanical alloying process

  17. Photoluminescent properties of silicon carbide and porous silicon carbide after annealing

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ki-Hwan; Lee, Seung-Koo [Department of Chemistry, Kongju National University, Kongju 314-701 (Korea, Republic of); Jeon, Ki-Seok, E-mail: ksjeon@kongju.ac.kr [Fusion Biotechnology Research Center, KRICT, Daejeon 305-600 (Korea, Republic of)

    2009-02-01

    Photoluminescent (PL) p-type 6H porous silicon carbides (PSCs), which showed a strong blue-green photoluminescence band centered at approximately 490 nm, were annealed in Ar and vacuum conditions. The morphological, optical, and chemical states after annealing are reported on electrochemically etched SiC semiconductors. The thermal treatments in the Ar and vacuum environments showed different trends in the PL spectra of the PSC. In particular, in the case of annealing in a vacuum, the PL spectra showed both a weak red PL peak near 630 nm and a relatively intense PL peak at around 430 nm in the violet region. SEM images showed that the etched surface had spherical nanostructures, mesostructures, and islands. With increasing annealing temperature it changes all spherical nanostructures. The average pore size observed at the surface of the PSC before annealing was of the order of approximately 10 nm. In order to investigate the surface of a series of samples in detail, both the detection of a particular chemical species and the electronic environments at the surface are examined using X-ray photoelectron spectroscopy (XPS). The chemical states from each XPS spectrum depend differently before and after annealing the surface at various temperatures. From these results, the PL spectra could be attributed not only to the quantum size effects but also to the oxide state.

  18. Photoluminescent properties of silicon carbide and porous silicon carbide after annealing

    International Nuclear Information System (INIS)

    Lee, Ki-Hwan; Lee, Seung-Koo; Jeon, Ki-Seok

    2009-01-01

    Photoluminescent (PL) p-type 6H porous silicon carbides (PSCs), which showed a strong blue-green photoluminescence band centered at approximately 490 nm, were annealed in Ar and vacuum conditions. The morphological, optical, and chemical states after annealing are reported on electrochemically etched SiC semiconductors. The thermal treatments in the Ar and vacuum environments showed different trends in the PL spectra of the PSC. In particular, in the case of annealing in a vacuum, the PL spectra showed both a weak red PL peak near 630 nm and a relatively intense PL peak at around 430 nm in the violet region. SEM images showed that the etched surface had spherical nanostructures, mesostructures, and islands. With increasing annealing temperature it changes all spherical nanostructures. The average pore size observed at the surface of the PSC before annealing was of the order of approximately 10 nm. In order to investigate the surface of a series of samples in detail, both the detection of a particular chemical species and the electronic environments at the surface are examined using X-ray photoelectron spectroscopy (XPS). The chemical states from each XPS spectrum depend differently before and after annealing the surface at various temperatures. From these results, the PL spectra could be attributed not only to the quantum size effects but also to the oxide state.

  19. Positron annihilation characteristics of ODS and non-ODS EUROFER isochronally annealed

    Energy Technology Data Exchange (ETDEWEB)

    Ortega, Y. [Departamento de Fisica, Universidad Carlos III de Madrid, 28911 Leganes (Spain)], E-mail: yanicet@fis.ucm.es; Castro, V. de; Monge, M.A.; Munoz, A.; Leguey, T.; Pareja, R. [Departamento de Fisica, Universidad Carlos III de Madrid, 28911 Leganes (Spain)

    2008-05-31

    Yttrium oxide dispersion strengthened (ODS) and non-ODS EUROFER produced by mechanical alloying and hot isostatic pressing have been subjected to isochronal annealing up to 1523 K, and the evolution of the open-volume defects and their thermal stability have been investigated using positron lifetime and coincidence Doppler broadening (CDB) techniques. Transmission electron microscopy (TEM) observations have also been performed on the studied samples to verify the characteristics of the surviving defects after annealing at 1523 K. The CDB spectra of ODS EUROFER exhibit a characteristic signature that is attributed to positron annihilation in Ar-decorated cavities at the oxide particle/matrix interfaces. The variation of the positron annihilation parameters with the annealing temperature shows three stages: up to 623 K, between 823 and 1323 K, and above 1323 K. Three-dimensional vacancy clusters, or voids, are detected in either materials in as-HIPed condition and after annealing at T {<=} 623 K. In the temperature range 823-1323 K, these voids' growth and nucleation and the growth of other new species of voids take place. Above 1323 K, some unstable cavities start to anneal out, and cavities associated to oxide particles and other small precipitates survive to annealing at 1523 K. The TEM observations and the positron annihilation results indicate that these cavities should be decorated with Ar atoms absorbed during the mechanical alloying process.

  20. Analysis of annealing process on P3HT:PCBM-based polymer solar cells using optical and impedance spectroscopy.

    Science.gov (United States)

    Kim, Jun Young; Noh, Seunguk; Kwak, Jeonghun; Lee, Changhee

    2013-05-01

    Thermal annealing is a well-known process for polymer solar cells because it improves the device characteristics. Especially, the carrier mobility and the light absorption of P3HT:PCBM are significantly improved after the annealing process. Here, we examined the changes in the morphology of P3HT:PCBM film according to the annealing temperature to find the changes during the thermal annealing process by measuring the optical absorption and X-ray diffraction. We also investigated the effect of two different annealing process (pre- and post-annealing) on the device performance of the standard polymer solar cells consisting of ITO/MoO3 (10 nm)/P3HT:PCBM (150 nm)/LiF (0.5 nm)/Al (100 nm) by measuring current density-voltage and impedance characteristics. From the results, we found that the improvement in terms of the power conversion efficiency of the post-annealed device originated from the decrease of injection resistance between P3HT:PCBM layer and Al electrodes.

  1. A numerical model for the thermal history of rocks based on confined horizontal fission tracks

    International Nuclear Information System (INIS)

    Jensen, P.K.; Kunzendorf, Helmar; Hansen, Kirsten

    1992-01-01

    A numerical model for determination of the thermal history of rocks is presented. It is shown that the thermal history may be uniquely determined as a piece-by-piece linear function on the basis of etched confined, horizontal fission track length distributions, their surface densities, and the uranium content. The initial track length distribution is taken into account. A relation between the measured track length distribution and age is given which includes correction for partial annealing. The annealing model used is the fanning Arrhenius plot. It is shown that track length distributions measured in transmitted light are biased favouring short tracks compared with measurements in reflected light. Testing of the model is performed on apatites from a tuffaceous sandstone from Bornholm (Denmark) yielding an estimate of the thermal history for the period of about 280 Ma back in time. (author)

  2. AFM, XRD and HRTEM Studies of Annealed FePd Thin Films

    International Nuclear Information System (INIS)

    Perzanowski, M.; Zabila, Y.; Polit, A.; Krupinski, M.; Dobrowolska, A.; Marszalek, M.; Morgiel, J.

    2010-01-01

    Ferromagnetic FePd L1 0 ordered alloys are highly expected as forthcoming high-density recording materials, because they reveal a large perpendicular magnetocrystalline anisotropy. The value of the magnetic anisotropy of FePd alloy strongly depends on the alloy composition, degree of alloy order as well as on the crystallographic grain orientation. In particular, to obtain the perpendicular anisotropy, it is necessary to get the films with (001) texture. One of the successful methods, which allows one to obtain highly ordered alloy, is a subsequent deposition of Fe and Pd layers, followed by an annealing at high temperature. This paper presents the study of the FePd thin alloy film structure changing in the result of high temperature annealing. During the annealing in high vacuum, the measurements of electrical resistance were performed, indicating the regions of different structure evolution. Changes in the crystal structure and surface morphology induced by thermal treatment were investigated by X-ray diffraction, atomic force microscopy, as well as high resolution transmission electron microscopy and then compared with electrical resistivity measurement. The slow thermal annealing of the deposited layers leads to the formation of L1 0 ordered FePd alloy with preferred (111) grain orientation. After the annealing at the highest used temperature, the dewetting process was observed, resulting in a creation of well oriented, regular nanoparticles. (author)

  3. Raman Spectroscopy Study of Annealing-Induced Effects on Graphene Prepared by Micromechanical Exfoliation

    International Nuclear Information System (INIS)

    Song, Ji Eun; Ko, Taeg Yeoung; Ryu, Sun Min

    2010-01-01

    Raman spectroscopy was combined with AFM to investigate the effects of thermal annealing on the graphene samples prepared by the widely used micromechanical exfoliation method. Following annealing cycles, adhesive residues were shown to contaminate graphene sheets with thin molecular layers in their close vicinity causing several new intense Raman bands. Detailed investigation shows that the Raman scattering is very strong and may be enhanced by the interaction with graphene. Although the current study does not pinpoint detailed origins for the new Raman bands, the presented results stress that graphene prepared by the above method may require extra cautions when treated with heat or possibly solvents. Since its isolation from graphite, graphene has drawn a lot of experimental and theoretical research. These efforts have been mostly in pursuit of various applications such as electronics, sensors, stretchable transparent electrodes, and various composite materials. To accomplish such graphene-based applications, understanding chemical interactions of this new material with environments during various processing treatments will become more important. Since thermal annealing is widely used in various research of graphene for varying purposes such as cleaning, nanostructuring, reactions, etc., understanding annealing-induced effects is prerequisite to many fundamental studies of graphene. In this regard, it is to be noted that there has been a controversy on the cause of the annealing-induced hole doping in graphene

  4. Precision Laser Annealing of Focal Plane Arrays

    Energy Technology Data Exchange (ETDEWEB)

    Bender, Daniel A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); DeRose, Christopher [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Starbuck, Andrew Lea [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Verley, Jason C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Jenkins, Mark W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-09-01

    We present results from laser annealing experiments in Si using a passively Q-switched Nd:YAG microlaser. Exposure with laser at fluence values above the damage threshold of commercially available photodiodes results in electrical damage (as measured by an increase in photodiode dark current). We show that increasing the laser fluence to values in excess of the damage threshold can result in annealing of a damage site and a reduction in detector dark current by as much as 100x in some cases. A still further increase in fluence results in irreparable damage. Thus we demonstrate the presence of a laser annealing window over which performance of damaged detectors can be at least partially reconstituted. Moreover dark current reduction is observed over the entire operating range of the diode indicating that device performance has been improved for all values of reverse bias voltage. Additionally, we will present results of laser annealing in Si waveguides. By exposing a small (<10 um) length of a Si waveguide to an annealing laser pulse, the longitudinal phase of light acquired in propagating through the waveguide can be modified with high precision, <15 milliradian per laser pulse. Phase tuning by 180 degrees is exhibited with multiple exposures to one arm of a Mach-Zehnder interferometer at fluence values below the morphological damage threshold of an etched Si waveguide. No reduction in optical transmission at 1550 nm was found after 220 annealing laser shots. Modeling results for laser annealing in Si are also presented.

  5. Cylinder packing by simulated annealing

    Directory of Open Access Journals (Sweden)

    M. Helena Correia

    2000-12-01

    Full Text Available This paper is motivated by the problem of loading identical items of circular base (tubes, rolls, ... into a rectangular base (the pallet. For practical reasons, all the loaded items are considered to have the same height. The resolution of this problem consists in determining the positioning pattern of the circular bases of the items on the rectangular pallet, while maximizing the number of items. This pattern will be repeated for each layer stacked on the pallet. Two algorithms based on the meta-heuristic Simulated Annealing have been developed and implemented. The tuning of these algorithms parameters implied running intensive tests in order to improve its efficiency. The algorithms developed were easily extended to the case of non-identical circles.Este artigo aborda o problema de posicionamento de objetos de base circular (tubos, rolos, ... sobre uma base retangular de maiores dimensões. Por razões práticas, considera-se que todos os objetos a carregar apresentam a mesma altura. A resolução do problema consiste na determinação do padrão de posicionamento das bases circulares dos referidos objetos sobre a base de forma retangular, tendo como objetivo a maximização do número de objetos estritamente posicionados no interior dessa base. Este padrão de posicionamento será repetido em cada uma das camadas a carregar sobre a base retangular. Apresentam-se dois algoritmos para a resolução do problema. Estes algoritmos baseiam-se numa meta-heurística, Simulated Annealling, cuja afinação de parâmetros requereu a execução de testes intensivos com o objetivo de atingir um elevado grau de eficiência no seu desempenho. As características dos algoritmos implementados permitiram que a sua extensão à consideração de círculos com raios diferentes fosse facilmente conseguida.

  6. W/Cu thin film infrared reflector for TiNxOy based selective solar absorber with high thermal stability

    Science.gov (United States)

    Zhang, J.; Chen, T. P.; Liu, Y. C.; Liu, Z.; Yang, H. Y.

    2017-05-01

    The W/Cu thin film structure is deposited by magnetron sputtering to form the infrared reflector for the TiNxOy based selective solar absorber (SSA) that can be used in the low- and middle-temperature applications. The structural, chemical, and optical properties of the SSA layers that experienced thermal annealing at different temperatures for various durations have been investigated with the characterization techniques, including X-ray photoelectron spectroscopy, X-ray diffraction, atomic force microscopy, spectroscopic ellipsometry, and spectrophotometry. Without a W layer, the reflectance in both visible and infrared ranges of the SSA increases as a result of the crystallization of the Cu layer at elevated temperatures. With a W layer with appropriate film thickness, the increase of the reflectance in the visible range can be suppressed to maintain a high solar absorptance, whereas a high infrared reflectance can be maintained to achieve a low thermal emittance. It is shown that for the SiO2-TiNxOy-W-Cu-Glass SSA with a 15 nm W thin film, thermal annealing can significantly reduce the thermal emittance to a low value (e.g., 4.4% at the temperature of 400 °C for annealing at 400 °C for 6 h), whereas the solar absorptance can be maintained at a high value (e.g., 92.2% for the annealing at 400 °C for 6 h).

  7. Effect of convection on the thermal structure of the troposphere and lower stratosphere including the tropical tropopause layer in the South Asian monsoon region

    Science.gov (United States)

    Muhsin, M.; Sunilkumar, S. V.; Venkat Ratnam, M.; Parameswaran, K.; Krishna Murthy, B. V.; Emmanuel, Maria

    2018-04-01

    Influence of convection on the thermal structure of Troposphere and Lower Stratosphere (TLS) is investigated using radiosonde data, obtained from Trivandrum (8.5°N, 76.9°E), Gadanki (13.5°N, 79.2°E), Bhubaneswar (20.25°N, 85.83°E), Kolkata (22.65°N, 88.45°E) and Singapore (1.37°N, 103.98°E), collected during different convective categories classified based on the altitude of deep convective cloud tops (CT) in the period 2008-2014. During deep convective events, the temperature showed lower tropospheric cooling, an upper tropospheric warming and an anomalous cooling (warming) below (above) the cold point tropopause (CPT) with respect to the clear-sky value. While warming in the upper troposphere is strongest (∼2-4 K) around 10-12 km, anomalous cooling (warming) below (above) the CPT is maximum around 15.5 km (17.5 km) with values in the range of-2 to -4 K (3-6 K). These temperature perturbations are observed 5-6 days prior to the convective events. In response to deep convection, surface cooling up to ∼ -4 K is also observed. This study showed that the magnitude of cold and warm anomalies increases with strength of convection. During deep convection, the potential temperature (θ) shows a decrease (<5 K) in the tropical tropopause layer (TTL) from the TTL-base up to CPT compared to that on clear-sky days, confirming the vertical mixing of convective air from the lower atmosphere to the TTL-levels. Correlation analysis between different TTL parameters suggests that, as the cloud top altitude increases, along with the adiabatic process, diabatic process also plays a major role in the TTL. An interesting feature observed during deep convection is the ascent of TTL-base by ∼1.5 km and descent of CPT and TTL-top by 0.5 km, which effectively thins the TTL by ∼2 km.

  8. Modification of Patterned Nanoporous Gold Thin Film Electrodes via Electro-annealing and Electrochemical Etching

    Science.gov (United States)

    Dorofeeva, Tatiana

    Nanostructured materials have had a major impact on various fields, including medicine, catalysis, and energy storage, for the major part due to unique phenomena that arise at nanoscale. For this reason, there is a sustained need for new nanostructured materials, techniques to pattern them, and methods to precisely control their nanostructure. To that end, the primary focus of this dissertation is to demonstrate novel techniques to fabricate and tailor the morphology of a class of nanoporous metals, obtained by a process known as dealloying. In this process, while the less noble constituent of an alloy is chemically dissolved, surface-diffusion of the more noble constituent leads to self-assembly of a bicontinuous ligament network with characteristic porosity of ˜70% and ligament diameter of 10s of nanometers. As a model material produced by dealloying, this work employ nanoporous gold (np-Au), which has attracted significant attention of desirable features, such as high effective surface area, electrical conductivity, well-defined thiol-based surface modification strategies, microfabrication-compatibility, and biocompatibility. The most commonly method used to modify the morphology of np-Au is thermal treatment, where the enhanced diffusivity of the surface atoms leads to ligament (and consequently pore) coarsening. This method, however, is not conducive to modifying the morphology of thin films at specific locations on the film, which is necessary for creating devices that may need to contain different morphologies on a single device. In addition, coarsening attained by thermal treatment also leads to an undesirable reduction in effective surface area. In response to these challenges, this work demonstrates two different techniques that enables in situ modification of np-Au thin film electrodes obtained by sputter-deposition of a precursors silver-rich gold-silver alloy. The first method, referred to as electro-annealing, is achieved by injecting electrical

  9. Annealing Effects on the Magnetization of Co-Ni-B Amorphous Nanoparticles

    International Nuclear Information System (INIS)

    Vargas, J.M.

    2001-01-01

    Chemically prepared (Co x Ni 1-x ) 1 00 -y B y (x=0.5, 0.75, 1; y∼30) amorphous fine particles were characterized by x-ray diffraction, DTA and TGA, and in-situ magnetic measurement as a function of annealing temperature in an inert atmosphere.Magnetic measurement performed in as prepared and ∼150C degree annealed samples show an increase of the saturation magnetization and magnetic moment after thermal tretment.Room temperature magnetization increases by factors of ∼3 in average.These measurements may indicate a local re-ordering of the amorphous phase at temperatures much lower than the full crystallization temperature

  10. Annealing of natural metamict zircons: II high degree of radiation damage

    CERN Document Server

    Colombo, M

    1998-01-01

    In situ time-dependent high-temperature X-ray powder diffraction was used to study the amorphous to crystalline transition in natural zircons which are characterized by a high degree of radiation damage. It was possible to distinguish two stages of the annealing process: (i) the recovery of the heavily disturbed but still crystalline domains and (ii) the recrystallization of the amorphous regions. The first stage is very fast under the chosen experimental conditions and, at least apparently, is not thermally activated. The second stage is a diffusion-controlled process, whose products (zircon or zircon and zirconia phases) are strongly correlated to the annealing temperature.

  11. The effect of annealing on the elastoplastic and viscoelastic responses of isotactic polypropylene

    DEFF Research Database (Denmark)

    Drozdov, Aleksey D.; Christiansen, Jesper de Claville

    2003-01-01

    to thermal treatment and on specimens annealed at 140 C, and (iii) in a series of tensile relaxation tests on non-annealed specimens. Constitutive equations are derived for the elastoplastic and non-linear viscoelastic responses of semicrystalline polymers. A polymer is treated as an equivalent transient....... The elastoplastic behavior is modelled as sliding of junctions in meso-domains with respect to their reference positions driven by macro-deformation. The viscoelastic response is attributed to detachment of active strands from temporary junctions and attachment of dangling chains to the network. Constitutive...

  12. Annealing of natural metamict zircons: II high degree of radiation damage

    International Nuclear Information System (INIS)

    Colombo, M.; Chrosch, J.

    1998-01-01

    In situ time-dependent high-temperature X-ray powder diffraction was used to study the amorphous to crystalline transition in natural zircons which are characterized by a high degree of radiation damage. It was possible to distinguish two stages of the annealing process: (i) the recovery of the heavily disturbed but still crystalline domains and (ii) the recrystallization of the amorphous regions. The first stage is very fast under the chosen experimental conditions and, at least apparently, is not thermally activated. The second stage is a diffusion-controlled process, whose products (zircon or zircon and zirconia phases) are strongly correlated to the annealing temperature

  13. Annealing behavior of high permeability amorphous alloys

    International Nuclear Information System (INIS)

    Rabenberg, L.

    1980-06-01

    Effects of low temperature annealing on the magnetic properties of the amorphous alloy Co 71 4 Fe 4 6 Si 9 6 B 14 4 were investigated. Annealing this alloy below 400 0 C results in magnetic hardening; annealing above 400 0 C but below the crystallization temperature results in magnetic softening. Above the crystallization temperature the alloy hardens drastically and irreversibly. Conventional and high resolution transmission electron microscopy were used to show that the magnetic property changes at low temperatures occur while the alloy is truly amorphous. By imaging the magnetic microstructures, Lorentz electron microscopy has been able to detect the presence of microscopic inhomogeneities in this alloy. The low temperature annealing behavior of this alloy has been explained in terms of atomic pair ordering in the presence of the internal molecular field. Lorentz electron microscopy has been used to confirm this explanation

  14. Global warming: Temperature estimation in annealers

    Directory of Open Access Journals (Sweden)

    Jack Raymond

    2016-11-01

    Full Text Available Sampling from a Boltzmann distribution is NP-hard and so requires heuristic approaches. Quantum annealing is one promising candidate. The failure of annealing dynamics to equilibrate on practical time scales is a well understood limitation, but does not always prevent a heuristically useful distribution from being generated. In this paper we evaluate several methods for determining a useful operational temperature range for annealers. We show that, even where distributions deviate from the Boltzmann distribution due to ergodicity breaking, these estimates can be useful. We introduce the concepts of local and global temperatures that are captured by different estimation methods. We argue that for practical application it often makes sense to analyze annealers that are subject to post-processing in order to isolate the macroscopic distribution deviations that are a practical barrier to their application.

  15. Excitation intensity dependent photoluminescence of annealed two-dimensional MoS{sub 2} grown by chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Kaplan, D.; Swaminathan, V. [U.S. Army RDECOM-ARDEC, Fuze Precision Armaments and Technology Directorate, Picatinny Arsenal, New Jersey 07806 (United States); Mills, K. [U.S. Army RDECOM-ARDEC, Energetics, Warheads and Manufacturing Technology Directorate, Picatinny Arsenal, New Jersey 07806 (United States); Lee, J. [Agency for Defense Development, Yuseong, P.O. Box 35, Daejeon, 305-600 (Korea, Republic of); Torrel, S. [Department of Materials Science and Engineering, Piscataway, Rutgers, The State University of New Jersey, New Jersey 08854 (United States)

    2016-06-07

    Here, we present detailed results of Raman and photoluminescence (PL) characterization of monolayers of MoS{sub 2} grown by chemical vapor deposition (CVD) on SiO{sub 2}/Si substrates after thermal annealing at 150 °C, 200 °C, and 250 °C in an argon atmosphere. In comparison to the as-grown monolayers, annealing in the temperature range of 150–250 °C brings about significant changes in the band edge luminescence. It is observed that annealing at 150 °C gives rise to a 100-fold increase in the PL intensity and produces a strong band at 1.852 eV attributed to a free-to-bound transition that dominates over the band edge excitonic luminescence. This band disappears for the higher annealing temperatures. The improvement in PL after the 200 °C anneal is reduced in comparison to that obtained after the 150 °C anneal; this is suggested to arise from a decrease in the non-radiative lifetime caused by the creation of sulfur di-vacancies. Annealing at 250 °C degrades the PL in comparison to the as-grown sample because of the onset of disorder/decomposition of the sample. It is clear that the PL features of the CVD-grown MoS{sub 2} monolayer are profoundly affected by thermal annealing in Ar atmosphere. However, further detailed studies are needed to identify, unambiguously, the role of native defects and/or adsorbed species in defining the radiative channels in annealed samples so that the beneficial effect of improvement in the optical efficiency of the MoS{sub 2} monolayers can be leveraged for various device applications.

  16. Excitation intensity dependent photoluminescence of annealed two-dimensional MoS2 grown by chemical vapor deposition

    International Nuclear Information System (INIS)

    Kaplan, D.; Swaminathan, V.; Mills, K.; Lee, J.; Torrel, S.

    2016-01-01

    Here, we present detailed results of Raman and photoluminescence (PL) characterization of monolayers of MoS 2 grown by chemical vapor deposition (CVD) on SiO 2 /Si substrates after thermal annealing at 150 °C, 200 °C, and 250 °C in an argon atmosphere. In comparison to the as-grown monolayers, annealing in the temperature range of 150–250 °C brings about significant changes in the band edge luminescence. It is observed that annealing at 150 °C gives rise to a 100-fold increase in the PL intensity and produces a strong band at 1.852 eV attributed to a free-to-bound transition that dominates over the band edge excitonic luminescence. This band disappears for the higher annealing temperatures. The improvement in PL after the 200 °C anneal is reduced in comparison to that obtained after the 150 °C anneal; this is suggested to arise from a decrease in the non-radiative lifetime caused by the creation of sulfur di-vacancies. Annealing at 250 °C degrades the PL in comparison to the as-grown sample because of the onset of disorder/decomposition of the sample. It is clear that the PL features of the CVD-grown MoS 2 monolayer are profoundly affected by thermal annealing in Ar atmosphere. However, further detailed studies are needed to identify, unambiguously, the role of native defects and/or adsorbed species in defining the radiative channels in annealed samples so that the beneficial effect of improvement in the optical efficiency of the MoS 2 monolayers can be leveraged for various device applications.

  17. Laser annealing and defect study of chalcogenide photovoltaic materials

    Science.gov (United States)

    Bhatia, Ashish

    Cu(In,Ga)Se2 (CIGSe), CuZnSn(S,Se)4(CZTSSe), etc., are the potential chalcogenide semiconductors being investigated for next-generation thin film photovoltaics (TFPV). While the champion cell efficiency of CIGSe has exceeded 20%, CZTSSe has crossed the 10% mark. This work investigates the effect of laser annealing on CISe films, and compares the electrical characteristics of CIGSe (chalcopyrite) and CZTSe (kesterite) solar cells. Chapter 1 through 3 provide a background on semiconductors and TFPV, properties of chalcopyrite and kesterite materials, and their characterization using deep level transient spectroscopy (DLTS) and thermal admittance spectroscopy (TAS). Chapter 4 investigates electrochemical deposition (nonvacuum synthesis) of CISe followed by continuous wave laser annealing (CWLA) using a 1064 nm laser. It is found that CWLA at ≈ 50 W/cm2 results in structural changes without melting and dewetting of the films. While Cu-poor samples show about 40% reduction in the full width at half maximum of the respective x-ray diffraction peaks, identically treated Cu-rich samples register more than 80% reduction. This study demonstrates that an entirely solid-phase laser annealing path exists for chalcopyrite phase formation and crystallization. Chapter 5 investigates the changes in defect populations after pulse laser annealing in submelting regime of electrochemically deposited and furnace annealed CISe films. DLTS on Schottky diodes reveal that the ionization energy of the dominant majority carrier defect state changes nonmonotonically from 215+/-10 meV for the reference sample, to 330+/-10 meV for samples irradiated at 20 and 30 mJ/cm2, and then back to 215+/-10 meV for samples irradiated at 40 mJ/cm2. A hypothesis involving competing processes of diffusion of Cu and laser-induced generation of In vacancies may explain this behavior. Chapter 6 compares the electrical characteristics of chalcopyrite and kesterite materials. Experiments reveal CZTSe cell has an

  18. Structural relaxation in annealed hyperquenched basaltic glasses

    DEFF Research Database (Denmark)

    Guo, Xiaoju; Mauro, John C.; Potuzak, M.

    2012-01-01

    The enthalpy relaxation behavior of hyperquenched (HQ) and annealed hyperquenched (AHQ) basaltic glass is investigated through calorimetric measurements. The results reveal a common onset temperature of the glass transition for all the HQ and AHQ glasses under study, indicating that the primary...... relaxation is activated at the same temperature regardless of the initial departure from equilibrium. The analysis of secondary relaxation at different annealing temperatures provides insights into the enthalpy recovery of HQ glasses....

  19. Effects of annealing schedule on orientation of Bi3.2Nd0.8Ti3O12 ferroelectric film prepared by chemical solution deposition process

    International Nuclear Information System (INIS)

    He, H.Y.; Huang, J.F.; Cao, L.Y.; Wang, L.S.

    2006-01-01

    Fatigue-free Bi 3.2 Nd 0.8 Ti 3 O 12 ferroelectric thin films were successfully prepared on p-Si(1 1 1) substrate using chemical solution deposition process. The orientation and formation of thin film under different annealing schedules were studied. XRD analysis indicated that (2 0 0)-oriented films with degree of orientation of I (200) /I (117) = 2.097 and 0.466 were obtained by preannealing for 10 min at 400 deg. C followed by rapid thermal annealing for 3, 10 and 20 min at 700 deg. C, respectively (0 0 8)-oriented films with degree of orientation of I (008) /I (117) = 1.706 were obtained by rapid thermal annealing for 3 min at 700 deg. C without preannealing, and (0 0 8)-oriented films with degree of orientation of I (008) /I (117) = 0.719 were obtained by preheating the film from room temperature at 20 deg. C/min followed by annealing for 10 min at 700 deg. C. The a-axis and c-axis orientation decreased as increase of annealing time due to effects of (1 1 1)-oriented substrate. AFM analysis further indicated that preannealing at 400 deg. C for 10 min followed by rapid thermal annealing for 3 min at 700 deg. C resulted in formation of platelike crystallite parallel to substrate surface, however rapid thermal annealing for 3 min at 700 deg. C without preannealing resulted in columnar crystallite perpendicular to substrate surface

  20. Boosting quantum annealer performance via sample persistence

    Science.gov (United States)

    Karimi, Hamed; Rosenberg, Gili

    2017-07-01

    We propose a novel method for reducing the number of variables in quadratic unconstrained binary optimization problems, using a quantum annealer (or any sampler) to fix the value of a large portion of the variables to values that have a high probability of being optimal. The resulting problems are usually much easier for the quantum annealer to solve, due to their being smaller and consisting of disconnected components. This approach significantly increases the success rate and number of observations of the best known energy value in samples obtained from the quantum annealer, when compared with calling the quantum annealer without using it, even when using fewer annealing cycles. Use of the method results in a considerable improvement in success metrics even for problems with high-precision couplers and biases, which are more challenging for the quantum annealer to solve. The results are further enhanced by applying the method iteratively and combining it with classical pre-processing. We present results for both Chimera graph-structured problems and embedded problems from a real-world application.

  1. Energy Saving in Industrial Annealing Furnaces

    Directory of Open Access Journals (Sweden)

    Fatma ÇANKA KILIÇ

    2018-03-01

    Full Text Available In this study, an energy efficiency studies have been carried out in a natural gas-fired rolling mill annealing furnace of an industrial establishment. In this context, exhaust gas from the furnace has been examined in terms of waste heat potential. In the examinations that have been made in detail; waste heat potential was found as 3.630,31 kW. Technical and feasibility studies have been carried out to realize electricity production through an Organic Rankine Cycle (ORC system for evaluating the waste heat potential of the annealing furnace. It has been calculated that 1.626.378,88 kWh/year of electricity can be generated by using the exhaust gas waste heat of the annealing furnace through an ORC system to produce electric energy with a net efficiency of 16%. The financial value of this energy was determined as 436.032,18 TL/year and the simple repayment period of the investment was 8,12 years. Since the annealing period of the annealing furnace is 2800 hours/year, the investment has not been found to be feasible in terms of the feasibility studies. However, the investment suitability can be assured when the annealing furnace is operating at full capacity for 8,000 hours or more annually.

  2. In situ defect annealing of swift heavy ion irradiated CeO2 and ThO2 using synchrotron X-ray diffraction and a hydrothermal diamond anvil cell

    Energy Technology Data Exchange (ETDEWEB)

    Palomares, Raul I.; Tracy, Cameron L.; Zhang, Fuxiang; Park, Changyong; Popov, Dmitry; Trautmann, Christina; Ewing, Rodney C.; Lang, Maik

    2015-04-16

    Hydrothermal diamond anvil cells (HDACs) provide facile means for coupling synchrotron X-ray techniques with pressure up to 10 GPa and temperature up to 1300 K. This manuscript reports on an application of the HDAC as an ambient-pressure sample environment for performingin situdefect annealing and thermal expansion studies of swift heavy ion irradiated CeO2and ThO2using synchrotron X-ray diffraction. The advantages of thein situHDAC technique over conventional annealing methods include rapid temperature ramping and quench times, high-resolution measurement capability, simultaneous annealing of multiple samples, and prolonged temperature and apparatus stability at high temperatures. Isochronal annealing between 300 and 1100 K revealed two-stage and one-stage defect recovery processes for irradiated CeO2and ThO2, respectively, indicating that the morphology of the defects produced by swift heavy ion irradiation of these two materials differs significantly. These results suggest that electronic configuration plays a major role in both the radiation-induced defect production and high-temperature defect recovery mechanisms of CeO2and ThO2.

  3. An efficient method combining thermal annealing and acid leaching ...

    Indian Academy of Sciences (India)

    Thus obtained silica was investigated by inductively coupled plasma atomic emission spectrometry (ICP–AES) method. Major impurities present in silica sand were Al, K, Fe, Na, Ca, Mg and B. Among the new products, almost major impurities were removed effectively. Indeed purity degree, given by characterization of ...

  4. Influence of mechanical milling and thermal annealing on electrical ...

    Indian Academy of Sciences (India)

    Wintec

    ⋅055–FeCo solution was added into the reaction vessel containing. 1⋅5 l of boiling 0⋅725 M NaOH aqueous solution under mechanical stirring at 500 rpm. The ferrite formation was monitored by sampling the suspension during the contact.

  5. An efficient method combining thermal annealing and acid leaching ...

    Indian Academy of Sciences (India)

    Si is the use of silica with high purity. To achieve this goal, an efficient purification process for sili- ca is needed. Many studies were carried out in this field for various purposes and using various techniques. Among these techniques one can cite ...

  6. Characterization of nanoscale multilayer structures upon thermal annealing

    NARCIS (Netherlands)

    Makhotkin, Igor Alexandrovich; Zameshin, Andrey; van de Kruijs, Robbert Wilhelmus Elisabeth; Yakshin, Andrey; Bijkerk, Frederik

    2015-01-01

    Obtaining a high quality physical description of the layered structure of multilayer based optical coatings is an essential part of the optimization of their optical performance. Grazing incidence X-ray reflectivity (GIXR) is one of the most informative and easy-to-use non-destructive tools for the

  7. Influence of mechanical milling and thermal annealing on electrical ...

    Indian Academy of Sciences (India)

    Wintec

    vibrating sample magnetometer (VSM, EG&G, PARC,. Model 4500, USA) with a maximum available field of. 0⋅7 T. The extended X-ray absorption fine structure. (EXAFS) measurements were done using a laboratory. X-ray absorption spectrometer (Rigaku R-XAS Lopper) at Ni K (8332 eV) and Zn K (9663 eV) absorption ...

  8. Characterization of tungsten silicides formed by rapid thermal annealing

    International Nuclear Information System (INIS)

    Siegal, M.; Santiago, J.J.; VanDerSpiegel, J.

    1986-01-01

    Tungsten silicide samples were formed by sputter depositing 80 nm W metal onto (100) oriented, 5 ohm-cm Si wafers. After deposition, the samples were fast radiatively processed in an RTA system using quartz-halogen tungsten lamps as radiation sources for time intervals ranging from 20 to 60s under high vacuum. Films processed at 22-25 W/cm 2 radiation with the film side of the samples oriented away from the lamps result in films which are metallic or cloudy in color, and have mixed composition as evidenced by x-ray diffraction (W, W 5 Si 3 and WSi 2 ). Films processed with the film side oriented toward the lamps show the occurrence of a phase transformation clearly nucleated at the film edge

  9. An efficient method combining thermal annealing and acid leaching ...

    Indian Academy of Sciences (India)

    Abstract. This work investigates the photothermal treatment of silica sand to reduce impurities to a low level suitable for the production of acceptable solar grade silicon for photovoltaic application. It describes experiment carried out by using a tungsten lamp furnace to purify silica under controlled atmosphere. This process ...

  10. Tuning of Schottky Barrier Height at NiSi/Si Contact by Combining Dual Implantation of Boron and Aluminum and Microwave Annealing

    Directory of Open Access Journals (Sweden)

    Feng Sun

    2018-03-01

    Full Text Available Dopant-segregated source/drain contacts in a p-channel Schottky-barrier metal-oxide semiconductor field-effect transistor (SB-MOSFET require further hole Schottky barrier height (SBH regulation toward sub-0.1 eV levels to improve their competitiveness with conventional field-effect transistors. Because of the solubility limits of dopants in silicon, the requirements for effective hole SBH reduction with dopant segregation cannot be satisfied using mono-implantation. In this study, we demonstrate a potential solution for further SBH tuning by implementing the dual implantation of boron (B and aluminum (Al in combination with microwave annealing (MWA. By using such a method, not only has the lowest hole SBH ever with 0.07 eV in NiSi/n-Si contacts been realized, but also the annealing duration of MWA was sharply reduced to 60 s. Moreover, we investigated the SBH tuning mechanisms of the dual-implanted diodes with microwave annealing, including the dopant segregation, activation effect, and dual-barrier tuning effect of Al. With the selection of appropriate implantation conditions, the dual implantation of B and Al combined with the MWA technique shows promise for the fabrication of future p-channel SB-MOSFETs with a lower thermal budget.

  11. Sensitization of erbium in silicon-rich silica : the effect of annealing temperature and hydrogen passivation

    International Nuclear Information System (INIS)

    Wilkinson, A.R.; Forcales, M.; Elliman, R.G.

    2005-01-01

    This paper reports on the effect of annealing temperature and hydrogen passivation on the excitation cross-section and photoluminescence of erbium in silicon-rich silica. Samples were prepared by co-implantation of Si and Er into SiO 2 followed by a single thermal anneal at temperatures ranging from 800 to 1100 degrees C, and with or without hydrogen passivation performed at 500 degrees C. Using time-resolved photoluminescence, the effective erbium excitation cross-section is shown to increase by a factor 3, while the number of optically active erbium ions decreases by a factor of 4 with increasing annealing temperature. Hydrogen passivation is shown to increase the luminescence intensity and to shorten the luminescence lifetime at 1.54 μm only in the presence of Si nanocrystals. The implications fo these results for realizing a silicon-based optical amplifier are also discussed. (author). 19 refs., 3 figs

  12. Influence of the implantation and annealing parameters on the photoluminescence produced by Si hot implantation

    Energy Technology Data Exchange (ETDEWEB)

    Sias, U.S. [Instituto de Fisica - Universidade Federal do Rio Grande do Sul (UFRGS), C.P. 15051, 91501-970 Porto Alegre, RS (Brazil) and Centro Federal de Educacao Tecnologica de Pelotas (CEFET-RS), 96015-370 Pelotas, RS (Brazil)]. E-mail: uilson@cefetrs.tche.br; Behar, M. [Instituto de Fisica - Universidade Federal do Rio Grande do Sul (UFRGS), C.P. 15051, 91501-970 Porto Alegre, RS (Brazil); Boudinov, H. [Instituto de Fisica - Universidade Federal do Rio Grande do Sul (UFRGS), C.P. 15051, 91501-970 Porto Alegre, RS (Brazil); Moreira, E.C. [UFPel - UNIPAMPA, Campus Bage, 96400-970 Bage, RS (Brazil)

    2007-04-15

    We report an investigation on the effect of the fluence and annealing time on the photoluminescence (PL) from Si nanocrystals produced by hot implantation of Si into a SiO{sub 2} matrix followed by thermal treatment in nitrogen. We have varied the implantation fluence in a wide range, from 0.35 x 10{sup 17} to 4 x 10{sup 17} Si/cm{sup 2}. In addition, the PL evolution with the annealing time (1 up to 15 h) was studied for the samples implanted with fluences between 1 x 10{sup 17} and 4 x 10{sup 17} Si/cm{sup 2}. After annealing the spectra present two PL bands: one centered at 780 nm and a second one around 1000 nm. The influence of the studied parameters on the PL behavior of both bands suggests different origins for their emission. The results are discussed in terms of current models.

  13. Special Features of Induction Annealing of Friction Stir Welded Joints of Medium-Alloy Steels

    Science.gov (United States)

    Priymak, E. Yu.; Stepanchukova, A. V.; Bashirova, E. V.; Fot, A. P.; Firsova, N. V.

    2018-01-01

    Welded joints of medium-alloy steels XJY750 and 40KhN2MA are studied in the initial condition and after different variants of annealing. Special features of the phase transformations occurring in the welded steels are determined. Optimum modes of annealing are recommended for the studied welded joints of drill pipes, which provide a high level of mechanical properties including the case of impact loading.

  14. Structural behaviour of monolithic fuel plates during hot isostatic pressing and annealing

    International Nuclear Information System (INIS)

    Ozaltun, Hakan; Medvedev, Pavel G.

    2010-01-01

    This article presents thermo-mechanical analysis of the monolithic fuel plates and their structural behavior during fabrication and thermal annealing performed by commercial FE solver COMSOL Multiphysics. The detailed 3D non-linear FEM analysis of the monolithic fuel plates has been useful not only for benchmarking the new model, but also for obtaining an in-depth understanding of fuel-cladding stress/strain characteristics. In particular, the 3D FEM analysis has revealed existence of stress gradients at the fuel/cladding interface region which could lead to structural failure. Large difference in the coefficient of thermal expansions between the U-10Mo foil and AL6061-TO cladding is the main reason for these gradients. During the thermal transient, thermo-mechanical behavior of the plate is driven by the significant mismatch between thermal expansion and basic mechanical properties of the foil and the cladding materials. By using elasto-thermo-perfectly plastic material models, it was shown that cladding material exceeds its yield limit; and therefore, deforms plastically; while the fuel foil remains below its elastic limit. In addition, it was observed that fabrication-induced residual stresses play major role in overall performance of monolithic fuel plates. The simulation results show existence of the critical temperature at which the normal and shear components of stresses change from compressive to tensile on both cladding and fuel. Furthermore, thermo-mechanical analysis of dispersion fuel mini-plates was presented. In order to properly identify three dimensional stress states over the dispersion particles and cladding material, micro-structure based finite element simulation was performed. It was shown that residual stresses in dispersion fuels cannot be neglected and should be included in proceeding simulations. (author)

  15. Large quantity production of carbon and boron nitride nanotubes by mechano-thermal process

    International Nuclear Information System (INIS)

    Chen, Y.; Fitzgerald, J.D.; Chadderton, L.; Williams, J.S.; Campbell, S.J.

    2002-01-01

    Full text: Nanotube materials including carbon and boron nitride have excellent properties compared with bulk materials. The seamless graphene cylinders with a high length to diameter ratio make them as superstrong fibers. A high amount of hydrogen can be stored into nanotubes as future clean fuel source. Theses applications require large quantity of nanotubes materials. However, nanotube production in large quantity, fully controlled quality and low costs remains challenges for most popular synthesis methods such as arc discharge, laser heating and catalytic chemical decomposition. Discovery of new synthesis methods is still crucial for future industrial application. The new low-temperature mechano-thermal process discovered by the current author provides an opportunity to develop a commercial method for bulk production. This mechano-thermal process consists of a mechanical ball milling and a thermal annealing processes. Using this method, both carbon and boron nitride nanotubes were produced. I will present the mechano-thermal method as the new bulk production technique in the conference. The lecture will summarise main results obtained. In the case of carbon nanotubes, different nanosized structures including multi-walled nanotubes, nanocells, and nanoparticles have been produced in a graphite sample using a mechano-thermal process, consisting of I mechanical milling at room temperature for up to 150 hours and subsequent thermal annealing at 1400 deg C. Metal particles have played an important catalytic effect on the formation of different tubular structures. While defect structure of the milled graphite appears to be responsible for the formation of small tubes. It is found that the mechanical treatment of graphite powder produces a disordered and microporous structure, which provides nucleation sites for nanotubes as well as free carbon atoms. Multiwalled carbon nanotubes appear to grow via growth of the (002) layers during thermal annealing. In the case of BN

  16. Evolution on the structural and optical properties of SiOx films annealed in nitrogen atmosphere

    International Nuclear Information System (INIS)

    Coyopol, A.; Díaz-Becerril, T.; García-Salgado, G.; Juárez-Santisteban, H.; López, R.; Rosendo-Andrés, E.

    2014-01-01

    In this paper, thermal annealing in nitrogen atmosphere at temperatures from 900 to 1100 °C was done on the SiO x films to follow the changes in their optical and structural properties. Micro-Raman measurements revealed the existence of a nanocrystalline phase and it become dominant as the annealing temperature increased from 900 to 1100 °C. The last might be an indicative of presence of silicon clusters with high crystallization grade embedded in the SiO x matrix. X-ray diffractograms from samples annealed at 1100 °C showed reflections at 2θ=28.4, 47.3, and 56.1° ascribed to (1 1 1), (2 2 0), and (3 1 1) planes of the silicon respectively. HRTEM measurements confirmed the existence of silicon nanocrystals (Si-ncs) in the SiO x films and both the average size and number of the Si-ncs were modified by the annealing process. Photoluminescence (PL) measurement displayed a broad emission from 400 to 1100 nm. This emission was related to the number of nanocrystals and to the creation of interface defects in SiO x films. -- Highlights: • Si-ncs are synthesized from interaction between a silicon solid-source and hydrogen atoms. • The size modulation of Si-ncs by effect of the annealing temperature is studied. • Silicon clusters consist of a crystalline core surrounded by an amorphous silicon shell. • The average size and number of the Si-ncs are modified by the annealing effect. • The increase in the number of Si-ncs with annealing process causes radiative centers

  17. Rapid capless annealing of28Si,64Zn, and9Be implants in GaAs

    Science.gov (United States)

    Liu, S. G.; Narayan, S. Y.

    1984-11-01

    We report the use of tungsten-halogen lamps for rapid (-10 s) thermal annealing of ion-implanted (100) GaAs under AsH3/Ar and N2 atmospheres. Annealing under flowing AsH3/Ar was carried out without wafer encapsulation. Rapid capless annealing activated implants in GaAs with good mobility and surface morphology. Typical mobilities were 3700 4500 cm2/V-s for n-layers with about 2×1017cm-3 carrier concentration and 50 150 cm2/v-s for 0.1 5xl019 cm-3 doped p-layers. Rapid thermal annealing was performed in a vertical quartz tube where different gases (N2, AsH3/H2, AsH3/Ar) can be introduced. Samples were encapsulated with SiO when N2 was used. Tungsten-halogen lamps of 600 or 1000 W were utilized for annealing GaAs wafers ranging from 1 to 10 cm2 in area and 0.025 to 0.040 cm in thickness. The transient temperature at the wafer position was monitored using a fine thermocouple. We carried out experiments for energies of 30 to 200 keV, doses of 2×1012 to 1×1015 cm-2, and peak temperatures ranging from 600 to 1000‡C. Most results quoted are in the 700 to 870‡C temperature range. Data on implant conditions, optimum anneal conditions, electrical characteristics, carrier concentration profiles, and atomic profiles of the implanted layers are described.

  18. Annealing behaviour of MeV erbium implanted lithium niobate

    Energy Technology Data Exchange (ETDEWEB)

    Gortmaker, P.; McCallum, J.C. [Royal Melbourne Inst. of Tech., VIC (Australia)

    1993-12-31

    Lithium niobate (LiNbO{sub 3}) is a crystalline ceramic commonly used in the fabrication of optoelectronic devices. Recently, rare earth doping of LiNbO{sub 3} has become a topic of particular interest. The electronic configuration of rare earth elements such as Erbium (Er) and Neodymium (Nd) allows them to lase in nearly any host matrix making fabrication of a whole range of new optoelectronic devices possible. At present, the doping technique, for LiNbO{sub 3} are centred upon diffusion technology, but the diffusion profiles for the rare earths are not generally well-matched to the optical modes of the device. The aim of this research is to develop MeV implantation and annealing conditions of rare earth doped LiNbO{sub 3} that would be compatible with optoelectronic device fabrication. To determine the characteristics of the rare earth elements in the LiNbO{sub 3} host material over the depth range of interest in optoelectronic device applications, high energy Rutherford backscattering spectrometry and ion channeling (RBS-C) must be used. Presented here are the Er depth profile and lattice damage results obtained from 5 MeV RBS-C measurements on samples of LiNbO{sub 3} implanted with various doses of MeV Erbium and subsequently thermally annealed at a temperature of 1000 deg C. It was found that there is a peak implant concentration (2 x 10{sup 16} Er/cm{sup 2}) for which erbium no longer goes substitutional in the lattice, and the implantation damage is not fully removed by annealing. 8 refs., 3 figs.

  19. Open-System Quantum Annealing in Mean-Field Models with Exponential Degeneracy*

    Directory of Open Access Journals (Sweden)

    Kostyantyn Kechedzhi

    2016-05-01

    Full Text Available Real-life quantum computers are inevitably affected by intrinsic noise resulting in dissipative nonunitary dynamics realized by these devices. We consider an open-system quantum annealing algorithm optimized for such a realistic analog quantum device which takes advantage of noise-induced thermalization and relies on incoherent quantum tunneling at finite temperature. We theoretically analyze the performance of this algorithm considering a p-spin model that allows for a mean-field quasiclassical solution and, at the same time, demonstrates the first-order phase transition and exponential degeneracy of states, typical characteristics of spin glasses. We demonstrate that finite-temperature effects introduced by the noise are particularly important for the dynamics in the presence of the exponential degeneracy of metastable states. We determine the optimal regime of the open-system quantum annealing algorithm for this model and find that it can outperform simulated annealing in a range of parameters. Large-scale multiqubit quantum tunneling is instrumental for the quantum speedup in this model, which is possible because of the unusual nonmonotonous temperature dependence of the quantum-tunneling action in this model, where the most efficient transition rate corresponds to zero temperature. This model calculation is the first analytically tractable example where open-system quantum annealing algorithm outperforms simulated annealing, which can, in principle, be realized using an analog quantum computer.

  20. Sequential multiple-step europium ion implantation and annealing of GaN

    KAUST Repository

    Miranda, S. M C

    2014-01-20

    Sequential multiple Eu ion implantations at low fluence (1×1013 cm-2 at 300 keV) and subsequent rapid thermal annealing (RTA) steps (30 s at 1000 °C or 1100 °C) were performed on high quality nominally undoped GaN films grown by metal organic chemical vapour deposition (MOCVD) and medium quality GaN:Mg grown by hydride vapour phase epitaxy (HVPE). Compared to samples implanted in a single step, multiple implantation/annealing shows only marginal structural improvement for the MOCVD samples, but a significant improvement of crystal quality and optical activation of Eu was achieved in the HVPE films. This improvement is attributed to the lower crystalline quality of the starting material, which probably enhances the diffusion of defects and acts to facilitate the annealing of implantation damage and the effective incorporation of the Eu ions in the crystal structure. Optical activation of Eu3+ ions in the HVPE samples was further improved by high temperature and high pressure annealing (HTHP) up to 1400 °C. After HTHP annealing the main room temperature cathodo- and photoluminescence line in Mg-doped samples lies at ∼ 619 nm, characteristic of a known Mg-related Eu3+ centre, while after RTA treatment the dominant line lies at ∼ 622 nm, typical for undoped GaN:Eu. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.