WorldWideScience

Sample records for ternary chalcopyrite semiconductors

  1. Ternary chalcopyrite semiconductors

    CERN Document Server

    Shay, J L; Pamplin, B R

    2013-01-01

    Ternary Chalcopyrite Semiconductors: Growth, Electronic Properties, and Applications covers the developments of work in the I-III-VI2 and II-IV-V2 ternary chalcopyrite compounds. This book is composed of eight chapters that focus on the crystal growth, characterization, and applications of these compounds to optical communications systems. After briefly dealing with the status of ternary chalcopyrite compounds, this book goes on describing the crystal growth of II-IV-V2 and I-III-VI2 single crystals. Chapters 3 and 4 examine the energy band structure of these semiconductor compounds, illustrat

  2. Quadrupole interaction in ternary chalcopyrite semiconductors experiments and theory

    CERN Document Server

    Dietrich, M; Degering, D; Deicher, M; Kortus, J; Magerle, R; Möller, A; Samokhvalov, V; Unterricker, S; Vianden, R

    2000-01-01

    Electric field gradients have been measured at substitutional lattice sites in ternary semiconductors using perturbed gamma - gamma angular correlation spectroscopy. The experimental results for A/sup I/B/sup III/C/sub 2//sup VI/ chalcopyrite structure compounds and Square Operator A/sup II/B/sub 2//sup III/C/sub 4//sup VI/ defect chalcopyrites are compared with ab-initio calculations. The latter were carried out with the WIEN code that uses the full potential linearized augmented plane wave method within a density functional theory. The agreement between experiment and theory is in most cases very good. Furthermore, the anion displacements in AgGaX/sub 2/- compounds (X: S, Se, Te) have been determined theoretically by determining the minimum of the total energy of the electrons in an elementary cell. (20 refs).

  3. Optical analysis of absorbing thin films: application to ternary chalcopyrite semiconductors.

    Science.gov (United States)

    Hernández-Rojas, J L; Lucĺa, M L; Mátil, I; González-Díaz, G; Santamaría, J; Sánchez-Quesada, F

    1992-04-01

    The refractive index n and the absorption coefficient a of radio frequency sputtered CuGaSe(2) and CuInSe(2) thin films were obtained by means of transmissivity (T) and reflectivity (R) measurements at normal incidence. The optical properties were determined from the rigorous expressions for the transmission and the reflection in an air/film/(glass)substrate/air multilayer system. The solutions to this system of equations are not unique, and the physically meaningful solution is identified by trying different thicknesses in the numerical approach. Usually, nonacceptable n dispersion curves are found for all thicknesses. To be able to obtain a good n dispersion curve and, therefore, a correct absorption coefficient, we propose a simple modification of the equations for R and T through a factor called the coherence factor (CF). Because of the surface roughness and the nonuniformity of n and alpha, the light rays that reflect internally in the interface between the substrate and the film have a random difference in opt cal path. The CF accounts for this effect. This modification leads to an unambiguous and accurate determination of the optical properties and thickness of thin films for all wavelengths where transmission is not negligible. The CF is shown to be greatly dependent on the thickness of the film. This method can be used even when the R and T spectra do not have interference fringes. This method is applied successfully to the optical analyses, in the 0.4-2.5-mum wavelength range, of CuInSe(2) and CuGaSe(2) ternary chalcopyrite thin films deposited onto glass substrates by radio-frequency sputtering.

  4. An insight into the mechanism of charge-transfer of hybrid polymer:ternary/quaternary chalcopyrite colloidal nanocrystals

    Directory of Open Access Journals (Sweden)

    Parul Chawla

    2014-08-01

    Full Text Available In this work, we have demonstrated the structural and optoelectronic properties of the surface of ternary/quaternary (CISe/CIGSe/CZTSe chalcopyrite nanocrystallites passivated by tri-n-octylphosphine-oxide (TOPO and tri-n-octylphosphine (TOP and compared their charge transfer characteristics in the respective polymer: chalcopyrite nanocomposites by dispersing them in poly(3-hexylthiophene polymer. It has been found that CZTSe nanocrystallites due to their high crystallinity and well-ordered 3-dimensional network in its pristine form exhibit a higher steric- and photo-stability, resistance against coagulation and homogeneity compared to the CISe and CIGSe counterparts. Moreover, CZTSe nanocrystallites display efficient photoluminescence quenching as evident from the high value of the Stern–Volmer quenching constant (KSV and eventually higher charge transfer efficiency in their respective polymer P3HT:CZTSe composites. We modelled the dependency of the charge transfer from the donor and the charge separation mechanism across the donor–acceptor interface from the extent of crystallinity of the chalcopyrite semiconductors (CISe/CIGSe/CZTSe. Quaternary CZTSe chalcopyrites with their high crystallinity and controlled morphology in conjunction with regioregular P3HT polymer is an attractive candidate for hybrid solar cells applications.

  5. Chalcopyrite semimagnetic semiconductors: From nanocomposite to homogeneous material

    Directory of Open Access Journals (Sweden)

    Kilanski L.

    2014-01-01

    Full Text Available Currently, complex ferromagnetic semiconductor systems are of significant interest due to their potential applicability in spintronics. A key feature in order to use semiconductor materials in spintronics is the presence of room temperature ferromagnetism. This feature was recently observed and is intensively studied in several Mn-alloyed II-IV-V2 group diluted magnetic semiconductor systems. The paper reviews the origin of room temperature ferromagnetism in II-IV-V2 compounds. In view of our recent reports the room temperature ferromagnetism in Mn-alloyed chalcopyrite semiconductors with more than 5 molar % of Mn is due to the presence of MnAs clusters. The solubility of magnetic impurities in bulk II-IV-V2 materials is of the order of a few percent, depending on the alloy composition. High values of the conducting hole - Mn ion exchange constant Jpd have significant value equal to 0.75 eV for Zn0.997Mn0.003GeAs2. The sample quality has significant effect on the magnetotransport of the alloy. The magnetoresistance of the alloy change main physical mechanism from spin-disorder scattering and weak localization for homogeneous samples to cluster-related geometrical effect observed for nanocomposite samples. The magnetoresistance of the II-IV-V2 alloys can be then tuned up to a few hundreds of percent via changes of the chemical composition of the alloy as well as a degree of disorder present in a material. [Projekat Ministarstva nauke Republike Srbije, br. III45003

  6. Nonlinearity, optoelectronic properties, and their correlations for some mixed ternary defect chalcopyrites

    International Nuclear Information System (INIS)

    Roy, S Dutta

    2010-01-01

    The refractive index, optical nonlinearity, lowest energy band gap, and other related parameters of some mixed defect ternary chalcopyrites are calculated using Levine's bond charge model and its modification developed by Samanta et al. for multinary and mixed compounds. The dependence of the band gap energy on the average quantum number, molecular weight, and anion displacement parameter is shown for the first time, which will be very useful for designing various optoelectronic and nonlinear laser devices. (laser applications and other aspects of quantum electronics)

  7. Structural trends in off stoichiometric chalcopyrite type compound semiconductors

    International Nuclear Information System (INIS)

    Stephan, Christiane

    2011-01-01

    Energy supply is one of the most controversial topics that are currently discussed in our global community. Most of the energy delivered to the customer today has its origin in fossil and nuclear power plants. Indefinable risks and the radioactive waste repository problem of the latter as well as the global scarcity of fossil resources cause the renewable energies to grow more and more important for achieving sustainability. The main renewable energy sources are wind power, hydroelectric power and solar energy. On the photovoltaic (PV) market different materials are competing as part of different kinds of technologies, with the largest contribution still coming from wafer based crystalline silicon solar cells (95 %). Until now thin film solar cells only contribute a small portion to the whole PV market, but large capacities are under construction. Thin film photovoltaic shows a number of advantages in comparison to wafer based crystalline silicon PV. Among these material usage and production cost reduction are two prominent examples. The type of PV materials, which are analyzed in this work, are high potential compounds that are widely used as absorber layer in thin film solar cells. These are compound semiconductors of the type CuB III C VI 2 (B III = In, Ga and C VI = Se, S). Several years of research have already gone into understanding the efficiency limiting factors for solar cell devices fabricated from this compound. Most of the studies concerning electronic defects are done by spectroscopic methods mostly performed using thin films from different kinds of synthesis, without any real knowledge regarding the structural origin of these defects. This work shows a systematic fundamental structural study of intrinsic point defects that are present within the material at various compositions in CuB III C VI 2 compound semiconductors. The study is done on reference powder samples with well determined chemical composition and using advanced diffraction techniques

  8. Structural trends in off stoichiometric chalcopyrite type compound semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Stephan, Christiane

    2011-03-15

    Energy supply is one of the most controversial topics that are currently discussed in our global community. Most of the energy delivered to the customer today has its origin in fossil and nuclear power plants. Indefinable risks and the radioactive waste repository problem of the latter as well as the global scarcity of fossil resources cause the renewable energies to grow more and more important for achieving sustainability. The main renewable energy sources are wind power, hydroelectric power and solar energy. On the photovoltaic (PV) market different materials are competing as part of different kinds of technologies, with the largest contribution still coming from wafer based crystalline silicon solar cells (95 %). Until now thin film solar cells only contribute a small portion to the whole PV market, but large capacities are under construction. Thin film photovoltaic shows a number of advantages in comparison to wafer based crystalline silicon PV. Among these material usage and production cost reduction are two prominent examples. The type of PV materials, which are analyzed in this work, are high potential compounds that are widely used as absorber layer in thin film solar cells. These are compound semiconductors of the type CuB{sup III}C{sup VI}{sub 2} (B{sup III} = In, Ga and C{sup VI} = Se, S). Several years of research have already gone into understanding the efficiency limiting factors for solar cell devices fabricated from this compound. Most of the studies concerning electronic defects are done by spectroscopic methods mostly performed using thin films from different kinds of synthesis, without any real knowledge regarding the structural origin of these defects. This work shows a systematic fundamental structural study of intrinsic point defects that are present within the material at various compositions in CuB{sup III}C{sup VI}{sub 2} compound semiconductors. The study is done on reference powder samples with well determined chemical composition and

  9. Electronic modification of Cu-based chalcopyrite semiconductors induced by lattice deformation and composition alchemy

    Science.gov (United States)

    Jiang, F. D.; Feng, J. Y.

    2008-02-01

    Using first principles calculation, we systematically investigate the electronic modification of Cu-based chalcopyrite semiconductors induced by lattice deformation and composition alchemy. It is shown that the optical band gap Eg is remarkably sensitive to the anion displacement μ, resulting from the opposite shifts of conduction band minimum and valence band maximum. Meanwhile, the dependence of structural parameters of alloyed compounds on alloy composition x is demonstrated for both cation and anion alloying. The d orbitals of group-III cations are found to be of great importance in the calculation. Abnormal changes in the optical band gap Eg induced by anion alloying are addressed.

  10. Electronic modification of Cu-based chalcopyrite semiconductors induced by lattice deformation and composition alchemy

    International Nuclear Information System (INIS)

    Jiang, F D; Feng, J Y

    2008-01-01

    Using first principles calculation, we systematically investigate the electronic modification of Cu-based chalcopyrite semiconductors induced by lattice deformation and composition alchemy. It is shown that the optical band gap E g is remarkably sensitive to the anion displacement μ, resulting from the opposite shifts of conduction band minimum and valence band maximum. Meanwhile, the dependence of structural parameters of alloyed compounds on alloy composition x is demonstrated for both cation and anion alloying. The d orbitals of group-III cations are found to be of great importance in the calculation. Abnormal changes in the optical band gap E g induced by anion alloying are addressed

  11. Wurtzite-derived ternary I?III?O2 semiconductors

    OpenAIRE

    Omata, Takahisa; Nagatani, Hiraku; Suzuki, Issei; Kita, Masao

    2015-01-01

    Ternary zincblende-derived I?III?VI2 chalcogenide and II?IV?V2 pnictide semiconductors have been widely studied and some have been put to practical use. In contrast to the extensive research on these semiconductors, previous studies into ternary I?III?O2 oxide semiconductors with a wurtzite-derived ?-NaFeO2 structure are limited. Wurtzite-derived ?-LiGaO2 and ?-AgGaO2 form alloys with ZnO and the band gap of ZnO can be controlled to include the visible and ultraviolet regions. ?-CuGaO2, which...

  12. Properties of Wide-Gap Chalcopyrite Semiconductors for Photovoltaic Applications: Final Report, 8 July 1998 -- 17 October 2001

    Energy Technology Data Exchange (ETDEWEB)

    Rockett, A.

    2003-07-01

    The objectives of this project were to obtain a fundamental understanding of wide-gap chalcopyrite semiconductors and photovoltaic devices. Information to be gathered included significant new fundamental materials data necessary for accurate modeling of single- and tandem-junction devices, basic materials science of wider-gap chalcopyrite semiconductors to be used in next-generation devices, and practical information on the operation of devices incorporating these materials. Deposition used a hybrid sputtering and evaporation method shown previously to produce high-quality epitaxial layers of Cu(In,Ga)Se2 (CIGS). Materials analysis was also provided to assist members of the National CIS Team, of which, through this contract, we were a member. Solar cells produced from resulting single-crystal epitaxial layers in collaboration with various members of the CIS Team were used to determine the factors limiting performance of the devices based on analysis of the results. Because epitaxial growth allows us to determine the surface orientation of our films specifically by choice of the substrate surface on which the film is grown, a major focus of the project concerned the nature of (110)-oriented CIGS films and the performance of solar cells produced from these films. We begin this summary with a description of the results for growth on (110) GaAs, which formed a basis for much of the work ultimately conducted under the program.

  13. Lattice-matched heteroepitaxy of wide gap ternary compound semiconductors

    Science.gov (United States)

    Bachmann, Klaus J.

    A variety of applications are identified for heteroepitaxial structures of wide gap I-III-VI(sub 2) and II-IV-V(sub 2) semiconductors, and are assessed in comparison with ternary III-V alloys and other wide gap materials. Non-linear optical applications of the I-III-VI(sub 2) and II-IV-V(sub 2) compound heterostructures are discussed, which require the growth of thick epitaxial layers imposing stringent requirements on the conditions of heteroepitaxy. In particular, recent results concerning the MOCVD growth of ZnSi(x)Ge(1-x)P2 alloys lattice matching Si or GaP substrates are reviewed. Also, heterostructures of Cu(z)Ag(1-z)GaS2 alloys that lattice-match Si, Ge, GaP, or GaAs substrates are considered in the context of optoelectronic devices operating in the blue wavelength regime. Since under the conditions of MOCVD, metastable alloys of the II-IV-V(sub 2) compounds and group IV elements are realized, II-IV-V(sub 2) alloys may also serve as interlayers in the integration of silicon and germanium with exactly lattice-matched tetrahedrally coordinated compound semiconductors, e.g. ZnSi(x)Ge(1-x)P2.

  14. Electronic structure of semiconductor thin films (chalcopyrites) as absorbermaterials for thin film solar cells

    International Nuclear Information System (INIS)

    Lehmann, Carsten

    2007-01-01

    The objective of this work was to determine for the first time the band structure of CuInS 2 . For this purpose a new GSMBE process with TBDS as sulphur precursor was established to prevent the use of elemental sulphur in an UHV system. Additionally to the deposited films a cleave surface was prepared. The samples were characterized in situ by XPS/UPS and LEED. XRD and SEM were used for further ex situ investigations. The band structure was determined by ARUPS using synchrotron light. CuInS(001) and CuInS 2 (112) were deposited on Si and GaAs. The deposition of CuInS 2 on GaAs showed a strong dependence on the existing surface reconstruction. A 2 x 1 reconstruction of GaAs(001) yielded CuInS 2 (001) films featuring terraces. A deposition on 2 x 2 reconstructed GaAs(111)A surfaces led to a facetted CuInS 2 surface. On sulphur-passivated non-reconstructed GaAs(111)B a deposition of chalcopyrite ordered CuInS 2 free of facets was possible. On the surface of Cu-rich CuInS 2 films CuS crystallites formed. This yields ARUPS spectra showing the electronic stucture of CuInS 2 superimposed by non-dispergative states of the polycrystalline CuS segregations. The effective hole masses were derived from the k vertical stroke vertical stroke measurements. Finally the results of this work showed that the use of a (111) substrate leads to domain formation of the deposited CuInS 2 (112) films. Thus ARUPS spectra of such films show a superposition of the band structures along different directions. (orig.)

  15. The role of In in III-nitride ternary semiconductors

    CERN Document Server

    Redondo cubero, A

    This proposal aims to study the role of In in the outstanding efficiency of luminescent devices based on group III-nitride ternary semiconductors. To study the microscopic environments of In in GaInN and AlInN, Perturbed Angular Correlation (PAC) experiments will be performed using the PAC-probes $^{111m}$Cd($^{111}$Cd), $^{115}$Cd($^{115}$In) and $^{117}$Cd($^{117}$In). Temperature dependent PAC measurements using the $^{111}$In($^{111}$Cd) probe indicated that In in GaN and AlN forms a complex with a defect, possibly a nitrogen vacancy (V$_{N}$), which is stable up to high temperatures and might be involved in the luminescence mechanisms. Analysing these results two questions arose: \\\\ \\\\1. Does the fact that the actual measurement is performed with the daughter nucleus $^{111}$Cd (being an acceptor) influence the probe-defect interaction? This question can be answered by performing measurements with the complementary probe $^{117}$Cd($^{117}$In). \\\\ \\\\ 2. What is the significance of $\\textit{a...

  16. Electronic and structural properties of A Al2Se4 (A=Ag, Cu, Cd, Zn) chalcopyrite semiconductors

    International Nuclear Information System (INIS)

    Mishra, S.; Ganguli, B.

    2011-01-01

    We have studied the structural and electronic properties of defect chalcopyrite semiconductors A Al 2 Se 4 (A=Ag, Cu, Cd, Zn) using density functional theory (DFT) based first principle technique within tight binding linear muffin-tin orbital (TB-LMTO) method. Our calculated structural parameters such as lattice constants a and c, tetragonal distortion (η=c/2a) are in good agreement with experimental work. Anion displacement parameters, bond lengths and bulk modulus are also calculated. Our band structure calculation suggests that these compounds are direct band gap semiconductors having band gaps 2.40, 2.50, 2.46 and 2.82 eV for A Al 2 Se 4 (A=Ag, Cu, Cd, Zn) respectively. Calculated band gaps are in good agreement with other experimental and theoretical works within LDA limitation. We have made a quantitative estimation of the effect of p-d hybridization and structural distortion on the electronic properties. The reduction in band gap due to p-d hybridization is 19.47%, 21.29%, 0% and 0.7% for A Al 2 Se 4 (A=Ag, Cu, Cd, Zn) respectively. Increment of the band gap due to structural distortion is 11.62%, 2.45%, 2.92% and 9.30% in case of AgAl 2 Se 4 , CuAl 2 Se 4 , CdAl 2 Se 4 and ZnAl 2 Se 4 respectively. We have also discussed the bond nature of all four compounds. - Graphical abstract: Band structure and TDOS show the band gaps and effect of structural distortion on electronic properties. PDOS shows effect of p-d hybridization on band gaps for all four compounds. Highlights: → (Ag/Cu/Cd/Zn)Al 2 Se 4 have direct band gap of 2.4, 2.5, 2.46 and 2.82 eV respectively. → p-d hybridization reduces band gaps by 19.5%, 21.3% for (Ag/Cu)Al 2 Se 4 respectively. → No effects of? p-d hybridization on the band gaps for (Cd/Zn)Al 2 Se 4 and ZnAl 2 Se 4 . → Significant enhancement in band gap due to structural distortion in all the compounds. → Effects of bond nature on band gaps are also studied in all the compounds.

  17. Organic semiconductor: Insulator polymer ternary blends for photovoltaics

    Energy Technology Data Exchange (ETDEWEB)

    Ferenczi, Toby A.M. [Department of Physics, Blackett Laboratory, Imperial College London, London SW7 2AZ (United Kingdom); Mueller, Christian [Department of Materials, Eidgenoessische Technische Hochschule (ETH) Zuerich, CH-8093 Zuerich (Switzerland); Bradley, Donal D.C.; Nelson, Jenny [Department of Physics, Blackett Laboratory, Imperial College London, London SW7 2AZ (United Kingdom); Centre for Plastic Electronics, Imperial College London, London SW7 2AZ (United Kingdom); Smith, Paul [Department of Materials, Eidgenoessische Technische Hochschule (ETH) Zuerich, CH-8093 Zuerich (Switzerland); Centre for Plastic Electronics, Imperial College London, London SW7 2AZ (United Kingdom); Stingelin, Natalie [Department of Materials, Eidgenoessische Technische Hochschule (ETH) Zuerich, CH-8093 Zuerich (Switzerland); Centre for Plastic Electronics, Imperial College London, London SW7 2AZ (United Kingdom); Department of Materials, Imperial College London, London SW7 2AZ (United Kingdom)

    2011-09-15

    Ternary blends of poly(3-hexylthiophene): [6,6]-phenyl C{sub 61}-butyric acid methyl ester (P3HT:PC{sub 61}BM) and the insulating bulk polymers high-density polyethylene (HDPE), isotactic- and atactic polystyrene (i-PS, a-PS), are investigated. Addition of up to {approx}50 wt% of the electronically inert, semicrystalline HDPE and i-PS to the organic semiconducting system does not significantly degrade the performance of photovoltaic devices fabricated with these ternary blends. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  18. Crystal Growth of Ternary Compound Semiconductors in Low Gravity Environment

    Science.gov (United States)

    Su, Ching-Hua

    2014-01-01

    A low gravity material experiment will be performed in the Material Science Research Rack (MSRR) on International Space Station (ISS). There are two sections of the flight experiment: (I) crystal growth of ZnSe and related ternary compounds, such as ZnSeS and ZnSeTe, by physical vapor transport (PVT) and (II) melt growth of CdZnTe by directional solidification. The main objective of the project is to determine the relative contributions of gravity-driven fluid flows to the compositional distribution, incorporation of impurities and defects, and deviation from stoichiometry observed in the grown crystals as results of buoyancy-driven convection and growth interface fluctuations caused by irregular fluid-flows on Earth. The investigation consists of extensive ground-based experimental and theoretical research efforts and concurrent flight experimentation. This talk will focus on the ground-based studies on the PVT crystal growth of ZnSe and related ternary compounds. The objectives of the ground-based studies are (1) obtain the experimental data and conduct the analyses required to define the optimum growth parameters for the flight experiments, (2) perfect various characterization techniques to establish the standard procedure for material characterization, (3) quantitatively establish the characteristics of the crystals grown on Earth as a basis for subsequent comparative evaluations of the crystals grown in a low-gravity environment and (4) develop theoretical and analytical methods required for such evaluations. ZnSe and related ternary compounds have been grown by vapor transport technique with real time in-situ non-invasive monitoring techniques. The grown crystals have been characterized extensively by various techniques to correlate the grown crystal properties with the growth conditions.

  19. Effect of p–d hybridization, structural distortion and cation electronegativity on electronic properties of ZnSnX2 (X=P, As, Sb) chalcopyrite semiconductors

    International Nuclear Information System (INIS)

    Mishra, S.; Ganguli, B.

    2013-01-01

    Significant effects of p–d hybridization, structural distortion and cation-electro-negativity are found on band gap in ZnSnX 2 (X=P, As, Sb). Our study suggests these compounds to be direct band gap semiconductors with band gaps of 1.23, 0.68 and 0.19 eV respectively. Lattice constants, tetragonal distortion (η), anion displacement, bond lengths and bulk moduli are calculated by Density Functional Theory based on Tight binding Linear Muffin-Tin orbital method. Our result of structural properties is in good agreement with the available experimental and other theoretical results. Calculated band gaps also agree well with the experimental works within LDA limitation. Unlike other semiconductors in the group II–IV–V 2 , there is a reduction in the band gap of 0.22, 0.20 and 0.24 eV respectively in ZnSnX 2 (X=P, As, Sb) due to p–d hybridization. Structural distortion decreases band gap by 0.20, 0.12 and 0.10 eV respectively. We find that cation electronegativity effect is responsible for increasing the band gap relative to their binary analogs GaInP 2 , InGaAs 2 and GaInSb 2 respectively and increment are 0.13, 0.04 and 0.13 eV respectively. - Graphical abstract: One unit cell of ZnSnX 2 (X=P, As, Sb) chalcopyrite semiconductor. Semiconductors ZnSnX 2 (X=P, As, Sb) are found to be direct band gap semiconductors with band gaps 1.23, 0.68 and 0.19 eV respectively. The quantitative estimate of effects of p–d hybridization, structural distortion and cation electronegativity shows band gaps change significantly due to these effects. Highlights: ► ZnSnX 2 (X=P, As, Sb) are direct band gap semiconductors. ► These have band gaps of 1.23 eV, 0.68 eV and 0.19 eV respectively. ► The band gap reduction due to p–d hybridization is 13.41%, 18.51% and 40% respectively. ► Band gap reduction due to structural distortion is 12.12%, 11.11% and 16.66% respectively. ► Band gap increases 8.38%, 3.70% and 21.31% respectively due to cation electronegativity

  20. Analysis of the structural, electronic and optic properties of Ni doped MgSiP{sub 2} semiconductor chalcopyrite compound

    Energy Technology Data Exchange (ETDEWEB)

    Kocak, Belgin, E-mail: koakbelgin@gmail.com; Ciftci, Yasemin Oztekin, E-mail: yasemin@gazi.edu.tr [Gazi University, Department Of Physics, Teknikokullar, 06500, Ankara (Turkey)

    2016-03-25

    The structural, electronic band structure and optic properties of the Ni doped MgSiP{sub 2} chalcopyrite compound have been performed by using first-principles method in the density functional theory (DFT) as implemented in Vienna Ab-initio Simulation Package (VASP). The generalized gradient approximation (GGA) in the scheme of Perdew, Burke and Ernzerhof (PBE) is used for the exchange and correlation functional. The present lattice constant (a) follows generally the Vegard’s law. The electronic band structure, total and partial density of states (DOS and PDOS) are calculated. We present data for the frequency dependence of imaginary and real parts of dielectric functions of Ni doped MgSiP{sub 2}. For further investigation of the optical properties the reflectivity, refractive index, extinction coefficient and electron energy loss function are also predicted. Our obtained results indicate that the lattice constants, electronic band structure and optical properties of this compound are dependent on the substitution concentration of Ni.

  1. Effect of structural distortion and nature of bonding on the electronic properties of defect and Li-substituted CuInSe2 chalcopyrite semiconductors

    International Nuclear Information System (INIS)

    Mishra, S.; Ganguli, B.

    2012-01-01

    Highlights: ► CuInSe 2 , CuIn 2 Se 4 and Cu 0.5 Li 0.5 InSe 2 are direct band gap semiconductors of band gap 0.79 eV, 1.50 eV and 1.08 eV, respectively. ► The reduction in band gaps due to Se p–Cu d hybridization is 59.57% and 23.61% for CuInSe 2 and CuIn 2 Se 4 , respectively. ► Though Li does not have any d orbital contribution but its doping (Cu 0.5 Li 0.5 InSe 2 ) reduces the band gap significantly. The reduction due to Se p–Cu d hybridization and Li doping in Cu 0.5 Li 0.5 InSe 2 is 48.82%. ► There is significant reduction in band gap by 16.85%, 9.10% and 0.92% due to structural distortion in all the compounds, respectively. ► Effect of bond nature on electronic properties is also discussed on the basis of electronegativity differences of the atoms in all three compounds. - Abstract: We report the structural and electronic properties of chalcopyrite semiconductors CuInSe 2 , CuIn 2 Se 4 and Cu 0.5 Li 0.5 InSe 2 . Our calculation is based on density functional theory within tight binding linear muffin-tin orbital (TB-LMTO) method. The calculated lattice constants, anion displacement parameter (u), tetragonal distortion parameter (η = c/2a) and bond lengths agree well with experimental values. Our result shows these compounds are direct band gap semiconductors. Our calculated band gaps, 0.79 eV and 1.08 eV of CuInSe 2 and Cu 0.5 Li 0.5 InSe 2 , respectively, agree well with the experimental values within the limitation of LDA. The band gap of CuIn 2 Se 4 is found to be 1.50 eV. The band gap is reduced by 59.57%, 23.61% and 48.82% due to p–d hybridization and reduced by 16.85%, 9.10% and 0.92% due to structural distortion for CuInSe 2 , CuIn 2 Se 4 and Cu 0.5 Li 0.5 InSe 2 , respectively. We also discuss the effect of bond nature on electronic properties of all three compounds.

  2. Mechanical properties of some binary, ternary and quaternary III-V compound semiconductor alloys

    International Nuclear Information System (INIS)

    Navamathavan, R.; Arivuoli, D.; Attolini, G.; Pelosi, C.; Choi, Chi Kyu

    2007-01-01

    Vicker's microindentation tests have been carried out on InP/InP, GaAs/InP, InGaAs/InP and InGaAsP/InP III-V compound semiconductor alloys. The detailed mechanical properties of these binary, ternary and quaternary epilayers were determined from the indentation experiments. Microindentation studies of (1 1 1) GaAs/InP both A and B faces show that the hardness value increases with load and attains a constant for further increase in load and the microhardness values were found to lie between 3.5 and 4.0 GPa. The microhardness values of InGaAs/InP epilayers with different thickness were found to lie between 3.93 and 4.312 GPa. The microhardness values of InGaAsP/InP with different elemental composition were found to lie between 5.08 and 5.73 GPa. The results show that the hardness of the quaternary alloy drastically increases, the reason may be that the increase in As concentration hardens the lattice when phosphorous concentration is less and hardness decreases when phosphorous is increased. It was interestingly observed that the hardness value increases as we proceed from binary to quaternary III-V compound semiconductor alloys

  3. Theoretical prediction and experimental confirmation of unusual ternary ordered semiconductor compounds in Sr-Pb-S system.

    Science.gov (United States)

    Hao, Shiqiang; Zhao, Li-Dong; Chen, Chang-Qiang; Dravid, Vinayak P; Kanatzidis, Mercouri G; Wolverton, Christopher M

    2014-01-29

    We examine the thermodynamics of phase separation and ordering in the ternary Ca(x)Pb(1-x)S and Sr(x)Pb(1-x)S systems by density-functional theory combined with a cluster expansion and Monte Carlo simulations. Similar to most other ternary III-V or IV-VI semiconductor alloys, we find that bulk phase separation is thermodynamically preferred for PbS-CaS. However, we predict the surprising existence of stable, ordered ternary compounds in the PbS-SrS system. These phases are previously unreported ordered rocksalt-based compounds: SrPb3S4, SrPbS2, and Sr3PbS4. The stability of these predicted ordered phases is confirmed by transmission electron microscopy observations and band gap measurements. We believe this work paves the way for a combined theory-experiment approach to decipher complex phase relations in multicomponent chalcogenide systems.

  4. Surface Properties and Photocatalytic Activity of KTaO3, CdS, MoS2 Semiconductors and Their Binary and Ternary Semiconductor Composites

    Directory of Open Access Journals (Sweden)

    Beata Bajorowicz

    2014-09-01

    Full Text Available Single semiconductors such as KTaO3, CdS MoS2 or their precursor solutions were combined to form novel binary and ternary semiconductor nanocomposites by the calcination or by the hydro/solvothermal mixed solutions methods, respectively. The aim of this work was to study the influence of preparation method as well as type and amount of the composite components on the surface properties and photocatalytic activity of the new semiconducting photoactive materials. We presented different binary and ternary combinations of the above semiconductors for phenol and toluene photocatalytic degradation and characterized by X-ray powder diffraction (XRD, UV-Vis diffuse reflectance spectroscopy (DRS, scanning electron microscopy (SEM, Brunauer–Emmett–Teller (BET specific surface area and porosity. The results showed that loading MoS2 onto CdS as well as loading CdS onto KTaO3 significantly enhanced absorption properties as compared with single semiconductors. The highest photocatalytic activity in phenol degradation reaction under both UV-Vis and visible light irradiation and very good stability in toluene removal was observed for ternary hybrid obtained by calcination of KTaO3, CdS, MoS2 powders at the 10:5:1 molar ratio. Enhanced photoactivity could be related to the two-photon excitation in KTaO3-CdS-MoS2 composite under UV-Vis and/or to additional presence of CdMoO4 working as co-catalyst.

  5. Wide-Gap Chalcopyrites

    CERN Document Server

    Siebentritt, Susanne

    2006-01-01

    Chalcopyrites, in particular those with a wide band gap, are fascinating materials in terms of their technological potential in the next generation of thin-film solar cells and in terms of their basic material properties. They exhibit uniquely low defect formation energies, leading to unusual doping and phase behavior and to extremely benign grain boundaries. This book collects articles on a number of those basic material properties of wide-gap chalcopyrites, comparing them to their low-gap cousins. They explore the doping of the materials, the electronic structure and the transport through interfaces and grain boundaries, the formation of the electric field in a solar cell, the mechanisms and suppression of recombination, the role of inhomogeneities, and the technological role of wide-gap chalcopyrites.

  6. Electronic structure of semiconductor thin films (chalcopyrites) as absorbermaterials for thin film solar cells; Elektronische Struktur duenner Halbleiterfilme (Chalkopyrite) als Absorbermaterialien fuer Duennschichtsolarzellen

    Energy Technology Data Exchange (ETDEWEB)

    Lehmann, Carsten

    2007-12-11

    The objective of this work was to determine for the first time the band structure of CuInS{sub 2}. For this purpose a new GSMBE process with TBDS as sulphur precursor was established to prevent the use of elemental sulphur in an UHV system. Additionally to the deposited films a cleave surface was prepared. The samples were characterized in situ by XPS/UPS and LEED. XRD and SEM were used for further ex situ investigations. The band structure was determined by ARUPS using synchrotron light. CuInS(001) and CuInS{sub 2}(112) were deposited on Si and GaAs. The deposition of CuInS{sub 2} on GaAs showed a strong dependence on the existing surface reconstruction. A 2 x 1 reconstruction of GaAs(001) yielded CuInS{sub 2}(001) films featuring terraces. A deposition on 2 x 2 reconstructed GaAs(111)A surfaces led to a facetted CuInS{sub 2} surface. On sulphur-passivated non-reconstructed GaAs(111)B a deposition of chalcopyrite ordered CuInS{sub 2} free of facets was possible. On the surface of Cu-rich CuInS{sub 2} films CuS crystallites formed. This yields ARUPS spectra showing the electronic stucture of CuInS{sub 2} superimposed by non-dispergative states of the polycrystalline CuS segregations. The effective hole masses were derived from the k {sub vertical} {sub stroke} {sub vertical} {sub stroke} measurements. Finally the results of this work showed that the use of a (111) substrate leads to domain formation of the deposited CuInS{sub 2}(112) films. Thus ARUPS spectra of such films show a superposition of the band structures along different directions. (orig.)

  7. Direct femtosecond observation of charge carrier recombination in ternary semiconductor nanocrystals: The effect of composition and shelling

    KAUST Repository

    Bose, Riya

    2015-02-12

    Heavy-metal free ternary semiconductor nanocrystals are emerging as key materials in photoactive applications. However, the relative abundance of intra-bandgap defect states and lack of understanding of their origins within this class of nanocrystals are major factors limiting their applicability. To remove these undesirable defect states which considerably shorten the lifetimes of photogenerated excited carriers, a detailed understanding about their origin and nature is required. In this report, we monitor the ultrafast charge carrier dynamics of CuInS2 (CIS), CuInSSe (CISSe), and CuInSe2 (CISe) nanocrystals, before and after ZnS shelling, using state-of-the-art time-resolved laser spectroscopy with broadband capabilities. The experimental results demonstrate the presence of both electron and hole trapping intra-bandgap states in the nanocrystals which can be removed significantly by ZnS shelling, and the carrier dynamics is slowed down. Another important observation remains the reduction of carrier lifetime in the presence of Se, and the shelling strategy is observed to be less effective at suppressing trap states. This study provides quantitative physical insights into the role of anion composition and shelling on the charge carrier dynamics in ternary CIS, CISSe, and CISe nanocrystals which are essential to improve their applicability for photovoltaics and optoelectronics.

  8. Determining the Presence of Ordering in Ternary Semiconductor Alloys Grown by Molecular Beam Epitaxy

    Science.gov (United States)

    2013-01-01

    as a simple measurement of film quality. 2. Motivation and Army Interest One common example of ordering seen in many semiconductor alloys is copper ...ARL U.S. Army Research Laboratory CuPt copper platinum Ga gallium GaInP gallium indium phosphide GaSb gallium antimonide HgCdTe mercury...RECORDS MGMT ATTN RDRL CIO LL TECHL LIB ATTN RDRL SEE I W SARNEY ADELPHI MD 20783-1197 TOTAL: 7 (1 ELEC, 6 HCS)

  9. Crystal growth of ZnSe and related ternary compound semiconductors by physical vapor transport

    Science.gov (United States)

    Su, Ching-Hua

    1993-01-01

    The materials to be investigated are ZnSe and related ternary semiconducting alloys (e.g., ZnS(x)Se(1-x), ZnTe(x)Se(1-x), and Zn(1-x)Cd(x)Se). These materials are useful for opto-electronic applications such as high efficient light emitting diodes and low power threshold and high temperature lasers in the blue-green region of the visible spectrum. The recent demonstration of its optical bistable properties also makes ZnSe a possible candidate material for digital optical computers. The investigation consists of an extensive ground-based study followed by flight experimentation, and involves both experimental and theoretical work. The objectives of the ground-based work are to establish the characteristics of the crystals grown on Earth as a basis for subsequent comparative evaluations of the crystals grown in a low gravity environment and to obtain the experimental data and perform the analyses required to define the optimum parameters for the flight experiments. During the six months of the Preliminary Definition Phase, the research efforts were concentrated on the binary compound ZnSe - the purification of starting materials of Se by zone refining, the synthesis of ZnSe starting materials, the heat treatments of the starting materials, the vapor transport rate measurements, the vapor partial pressure measurements of ZnSe, the crystal growth of ZnSe by physical vapor transport, and various characterization on the grown ZnSe crystals.

  10. Crystal structure of the ternary semiconductor compound thallium gallium sulfide, TlGaS{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Delgado, G.E. [Laboratorio de Cristalografia, Departamento de Quimica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela)]. E-mail: gerzon@ula.ve; Mora, A.J. [Laboratorio de Cristalografia, Departamento de Quimica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela); Perez, F.V. [Centro de Estudios de Semiconductores, Departamento de Fisica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela); Departamento de Fisica, Facultad de Ciencias, Universidad del Zulia, Zulia (Venezuela); Gonzalez, J. [Centro de Estudios de Semiconductores, Departamento de Fisica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela)

    2007-04-01

    Thallium gallium sulfide, TlGaS{sub 2}, a semiconductor compound, was prepared by solid-state reaction technique. Its crystal structure was determined by single-crystal X-ray diffraction. This material crystallizes in the monoclinic system with space group C2/c (No. 15), Z=16 and unit cell parameters a=10.2990(8)A, b=10.2840(8)A, c=15.1750(18)A, {beta}=99.603(4){sup o}. The structural refinement converged to R(F)=0.0999, R(F{sup 2})=0.0764 and S=1.067. The structure consists of a three-dimensional arrangement of distorted TlS{sub 8} and GaS{sub 4} polyhedrons. Four GaS{sub 4} tetrahedra form adamantine-like units of the type Ga{sub 4}S{sub 10}, which in turn connect through the corners forming layers that run along the [100] direction.

  11. Novel red-emission of ternary ZnCdSe semiconductor nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Shu-Ru, E-mail: srchung@nfu.edu.tw [National Formosa University, Graduate Institute of Materials Science and Green Energy Engineering (China); Wang, Kuan-Wen [National Central University, Institute of Materials Science and Engineering (China); Chen, Hong-Shuo; Chen, Hong-Hong [National Formosa University, Graduate Institute of Materials Science and Green Energy Engineering (China)

    2015-02-15

    The effect of chain lengths of fatty acids on the physical properties of CdSe and ZnCdSe semiconductor nanocrystals (NCs) synthesized by the colloidal chemistry procedure is investigated. The fatty acids, lauric acid (LA), and stearic acid (SA), with different lengths of carbon chains, are used to prepare CdSe and ZnCdSe NCs when hexyldecylamine (HDA) is applied as the sole surfactant. For CdSe–SA and ZnCdSe–SA, they have the same emission wavelength at 592 nm and the same particle size of 3.3 nm; however, their quantum yield (QY) is 75 and 16 %, respectively. In contrast, the emission wavelength of CdSe–LA and ZnCdSe–LA NCs is 609 and 615 nm, the particle size is about 3.5 and 4 nm under the same reaction time, and the QY of them are 33 and 59 %, respectively. The X-ray diffraction pattern shows that ZnCdSe NCs all have the wurtzite structure, and their main peaks are located between those of pure CdSe and ZnSe materials. The main phase of ZnCdSe–SA and ZnCdSe–LA is ZnSe and CdSe, respectively, implying that alloyed ZnCdSe NC can be prepared and ZnSe and CdSe phase can be promoted by SA and LA, respectively. Moreover, the QY of red-emission ZnCdSe–LA is higher than 50 %. These results suggest that the growth rate of CdSe as well as ZnCdSe NC can be enhanced by using LA as complex reagent and HDA as sole surfactant. It is expected that the reported effective synthetic strategy can be developed as a very practical, easy and not time-consuming approach to prepare red emissive NCs with high QY and high reproducibility.

  12. Organo-gallium/indium chalcogenide complexes of copper(I): molecular structures and thermal decomposition to ternary semiconductors.

    Science.gov (United States)

    Kluge, Oliver; Biedermann, Ralf; Holldorf, Joscha; Krautscheid, Harald

    2014-01-27

    Several organo-gallium/indium chalcogenide complexes of copper(I), stabilized by trialkylphosphines, were isolated, structurally characterized by using single-crystal X-ray diffraction, and investigated in thermolysis experiments. The syntheses with [E(Me3Si)2] (E=S, Se) as a starting material and a chalcogen source involve the elimination of volatile silyl acetate, silyl ethers, and methane from copper(I) acetate, and Group 13 metal trimethyl compounds, respectively. Chalcogenide complexes, according to the general formulas [(R3PCu)4(MeM)4E6] (1-6) and [(R3PCu)6(MeM)4M4S13] (7-9; with R=alkyl and M=Ga, In), and mixed chalcogenide-phenylchalcogenolate complexes [(iPr3PCuEPh)3(MeGaE)4] (10, 11) were isolated. The heavy atom cores of 1-6 consist of an octahedron of chalcogen atoms, interpenetrated by a cube of metal atoms. Depending on the steric demand of the phosphine ligands, two constitutions are observed; the metal atoms of the same element either forming tetrahedra, or parallelograms, respectively. This constitutional isomerism is further investigated by quantum chemical calculations. Complexes 7-9 contain a central sulfur atom, surrounded by two interpenetrating tetrahedra of Group 13 metal atoms, an octahedron of copper atoms, and an icosahedron of twelve outer sulfur atoms; the heavy atom framework of 10 and 11 is a "cut-out" of this structure. Thermolysis experiments include thermogravimetry measurements and subsequent Rietveld phase analysis of the residues by using powder X-ray diffraction. The homologous compounds 1, 3, 4, and 6 yield the respective crystalline ternary semiconductor material CuME2 at temperatures below 300 °C. Partial release of Me3 M during the thermolysis process results in excess copper in the residue and therefore in small amounts of additional binary copper chalcogenide phases or metallic CuM alloys. Compound 8 produces nanocrystalline CuGaS2 at about 300 °C. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. First-Principles Calculations of Structural, Electronic and Optical Properties of Ternary Semiconductor Alloys ZAs x Sb1- x ( Z = B, Al, Ga, In)

    Science.gov (United States)

    Bounab, S.; Bentabet, A.; Bouhadda, Y.; Belgoumri, Gh.; Fenineche, N.

    2017-08-01

    We have investigated the structural and electronic properties of the BAs x Sb 1- x , AlAs x Sb 1- x , GaAs x Sb 1- x and InAs x Sb 1- x semiconductor alloys using first-principles calculations under the virtual crystal approximation within both the density functional perturbation theory and the pseudopotential approach. In addition the optical properties have been calculated by using empirical methods. The ground state properties such as lattice constants, both bulk modulus and derivative of bulk modulus, energy gap, refractive index and optical dielectric constant have been calculated and discussed. The obtained results are in reasonable agreement with numerous experimental and theoretical data. The compositional dependence of the lattice constant, bulk modulus, energy gap and effective mass of electrons for ternary alloys show deviations from Vegard's law where our results are in agreement with the available data in the literature.

  14. Crystal Growth of ZnSe and Related Ternary Compound Semiconductors by Vapor Transport in Low Gravity

    Science.gov (United States)

    Su, Ching-Hua; Ramachandran, N.

    2013-01-01

    Crystals of ZnSe and related ternary compounds, such as ZnSeS and ZnSeTe, will be grown by physical vapor transport in the Material Science Research Rack (MSRR) on International Space Station (ISS). The objective of the project is to determine the relative contributions of gravity-driven fluid flows to the compositional distribution, incorporation of impurities and defects, and deviation from stoichiometry observed in the crystals grown by vapor transport as results of buoyance-driven convection and growth interface fluctuations caused by irregular fluid-flows on Earth. The investigation consists of extensive ground-based experimental and theoretical research efforts and concurrent flight experimentation. The objectives of the ground-based studies are (1) obtain the experimental data and conduct the analyses required to define the optimum growth parameters for the flight experiments, (2) perfect various characterization techniques to establish the standard procedure for material characterization, (3) quantitatively establish the characteristics of the crystals grown on Earth as a basis for subsequent comparative evaluations of the crystals grown in a low-gravity environment and (4) develop theoretical and analytical methods required for such evaluations. ZnSe and related ternary compounds have been grown by vapor transport technique with real time in-situ non-invasive monitoring techniques. The grown crystals have been characterized extensively by various techniques to correlate the grown crystal properties with the growth conditions.

  15. Energy gaps, effective masses and ionicity of AlxGa1-xSb ternary semiconductor alloys

    Science.gov (United States)

    Bouarissa, N.; Boucenna, M.; Saib, S.; Siddiqui, S. A.

    2017-12-01

    A pseudopotential calculation of the electronic structure of AlxGa1-xSb ternary alloys in the zinc-blende structure has been performed. The compositional dependence of energy gaps, electron and heavy hole effective masses and ionicity of the material system of interest have been examined and discussed. Special attention has been given to the effect of the alloy disorder on the direct (Γ-Γ) bandgap energy. It is found that all features of interest vary monotonically with increasing the Al concentration x. Besides, bandgap bowing parameters and extent of the direct-to-indirect bandgap transition have been determined. Our findings agree generally well with the data reported in the literature. Trends in ionicity are found to be consistent with the Phillips ionicity scale.

  16. Optical, Electrical and Photocatalytic Properties of the Ternary Semiconductors ZnxCd1-xS, CuxCd1-xS and CuxZn1-xS

    Directory of Open Access Journals (Sweden)

    Sandra Andrea Mayén-Hernández

    2014-01-01

    Full Text Available The effects of vacuum annealing at different temperatures on the optical, electrical and photocatalytic properties of polycrystalline and amorphous thin films of the ternary semiconductor alloys ZnxCd1-xS, CuxCd1-xS and CuxZn1-xS were investigated in stacks of binary semiconductors obtained by chemical bath deposition. The electrical properties were measured at room temperature using a four-contact probe in the Van der Pauw configuration. The energy band gap of the films varied from 2.30 to 2.85 eV. The photocatalytic activity of the semiconductor thin films was evaluated by the degradation of an aqueous methylene blue solution. The thin film of ZnxCd1-xS annealed under vacuum at 300°C exhibited the highest photocatalytic activity.

  17. Refractive index of ternary and quaternary compound semiconductors below the fundamental absorption edge: Linear and nonlinear effects

    International Nuclear Information System (INIS)

    Jensen, B.; Torabi, A.

    1985-01-01

    The index of refraction n is calculated as a function of frequency and mole fraction x for the following compounds: Hg/sub l-x/Cd/sub x/Te, Al/sub x/Ga/sub l-x/As, and In/sub l-x/Ga/sub x/As/sub y/P/sub l-y/ lattice matched to InP. Lattice matching of In/sub l-x/Ga/sub x/As/sub y/P/sub l-y/ to InP requires that x = 0.466 y. The theoretical result for the refractive index is obtained from a quantum mechanical calculation of the dielectric constant of a compound semiconductor. It is given in terms of the basic material parameters of band gap energy, effective electron mass m/sub n/, effective heavy hole mass m/sub rho/, spin orbit splitting energy, lattice constant, and carrier concentration n/sub e/ or rho for n-type or rho-type materials, respectively. If these quantities are known as functions of mole fraction x, there are no adjustable parameters involved. A negative change in the refractive index near the fundamental absorption edge is predicted on passing radiation through a crystal if the change in carrier concentration of the initially unoccupied conduction band is assumed proportional to internal intensity I. Comparison of theory with experimental data is given

  18. Efficient visible-light photocatalytic activity by band alignment in mesoporous ternary polyoxometalate-Ag2S-CdS semiconductors

    Science.gov (United States)

    Kornarakis, I.; Lykakis, I. N.; Vordos, N.; Armatas, G. S.

    2014-07-01

    Porous multicomponent semiconductor materials show improved photocatalytic performance due to the large and accessible pore surface area and high charge separation efficiency. Here we report the synthesis of well-ordered porous polyoxometalate (POM)-Ag2S-CdS hybrid mesostructures featuring a controllable composition and high photocatalytic activity via a two-step hard-templating and topotactic ion-exchange chemical process. Ag2S compounds and polyoxometalate cluster anions with different reduction potentials, such as PW12O403-, SiW12O404- and PMo12O403-, were employed as electron acceptors in these ternary heterojunction photocatalysts. Characterization by small-angle X-ray scattering, X-ray diffraction, transmission electron microscopy and N2 physisorption measurements showed hexagonal arrays of POM-Ag2S-CdS hybrid nanorods with large internal BET surface areas and uniform mesopores. The Keggin structure of the incorporated POM clusters was also verified by elemental X-ray spectroscopy microanalysis, infrared and diffuse-reflectance ultraviolet-visible spectroscopy. These new porous materials were implemented as visible-light-driven photocatalysts, displaying exceptional high activity in aerobic oxidation of various para-substituted benzyl alcohols to the corresponding carbonyl compounds. Our experiments show that the spatial separation of photogenerated electrons and holes at CdS through the potential gradient along the CdS-Ag2S-POM interfaces is responsible for the increased photocatalytic activity.Porous multicomponent semiconductor materials show improved photocatalytic performance due to the large and accessible pore surface area and high charge separation efficiency. Here we report the synthesis of well-ordered porous polyoxometalate (POM)-Ag2S-CdS hybrid mesostructures featuring a controllable composition and high photocatalytic activity via a two-step hard-templating and topotactic ion-exchange chemical process. Ag2S compounds and polyoxometalate cluster

  19. Ternary semiconductors NiZrSn and CoZrBi with half-Heusler structure: A first-principles study

    Science.gov (United States)

    Fiedler, Gregor; Kratzer, Peter

    2016-08-01

    The ternary semiconductors NiZrSn and CoZrBi with C 1b crystal structure are introduced by calculating their basic structural, electronic, and phononic properties using density functional theory. Both the gradient-corrected PBE functional and the hybrid functional HSE06 are employed. While NiZrSn is found to be a small-band-gap semiconductor (Eg=0.46 eV in PBE and 0.60 eV in HSE06), CoZrBi has a band gap of 1.01 eV in PBE (1.34 eV in HSE06). Moreover, effective masses and deformation potentials are reported. In both materials A B C , the intrinsic point defects introduced by species A (Ni or Co) are calculated. The Co-induced defects in CoZrBi are found to have a higher formation energy compared to Ni-induced defects in NiZrSn. The interstitial Ni atom (Nii) as well as the VNiNii complex introduce defect states in the band gap, whereas the Ni vacancy (VNi) only reduces the size of the band gap. While Nii is electrically active and may act as a donor, the other two types of defects may compensate extrinsic doping. In CoZrBi, only the VCoCoi complex introduces a defect state in the band gap. Motivated by the reported use of NiZrSn for thermoelectric applications, the Seebeck coefficient of both materials, both in the p -type and the n -type regimes, is calculated. We find that CoZrBi displays a rather large thermopower of up to 500 μ V /K when p doped, whereas NiZrSn possesses its maximum thermopower in the n -type regime. The reported difficulties in achieving p -type doping in NiZrSn could be rationalized by the unintended formation of Nii2 + in conjunction with extrinsic acceptors, resulting in their compensation. Moreover, it is found that all types of defects considered, when present in concentrations as large as 3%, tend to reduce the thermopower compared to ideal bulk crystals at T =600 K. For NiZrSn, the calculated thermodynamic data suggest that additional Ni impurities could be removed by annealing, leading to precipitation of a metallic Ni2ZrSn phase.

  20. Structural and thermal properties of ternary narrow-gap oxide semiconductor; wurtzite-derived β-CuGaO2.

    Science.gov (United States)

    Nagatani, Hiraku; Suzuki, Issei; Kita, Masao; Tanaka, Masahiko; Katsuya, Yoshio; Sakata, Osami; Miyoshi, Shogo; Yamaguchi, Shu; Omata, Takahisa

    2015-02-16

    The crystal structure of the wurtzite-derived β-CuGaO2 was refined by Rietveld analysis of high-resolution powder diffraction data obtained from synchrotron X-ray radiation. Its structural characteristics are discussed in comparison with the other I-III-VI2 and II-VI oxide semiconductors. The cation and oxygen tetrahedral distortions of the β-CuGaO2 from an ideal wurtzite structure are small. The direct band-gap nature of the β-CuGaO2, unlike β-Ag(Ga,Al)O2, was explained by small cation and oxygen tetrahedral distortions. In terms of the thermal stability, the β-CuGaO2 irreversibly transforms into delafossite α-CuGaO2 at >460 °C in an Ar atmosphere. The transformation enthalpy was approximately -32 kJ mol(-1), from differential scanning calorimetry. This value is close to the transformation enthalpy of CoO from the metastable zincblende form to the stable rock-salt form. The monovalent copper in β-CuGaO2 was oxidized to divalent copper in an oxygen atmosphere and transformed into a mixture of CuGa2O4 spinel and CuO at temperatures >350 °C. These thermal properties indicate that β-CuGaO2 is stable at ≤300 °C in both reducing and oxidizing atmospheres while in its metastable form. Consequently, this material could be of use in optoelectronic devices that do not exceed 300 °C.

  1. Surface characterization of activated chalcopyrite particles via the FLSmidth ROL process. Part 1: Electron microscope investigations

    DEFF Research Database (Denmark)

    Karcz, Adam Paul; Damø, Anne Juul; Illerup, Jytte Boll

    of copper(II) to dope the semiconductor lattice and thereby "activate" the chalcopyrite, thereby reducing leach times below 2 hours (>98% recovery). Because the activation plays a major role in accelerating the leaching step, it is critical to understand the nature of this intermediate and its part...... in the ROL process. The current work presents results from electron microscope investigations of surface-activated particles....

  2. Ternary superconductors

    International Nuclear Information System (INIS)

    Giorgi, A.L.

    1987-01-01

    Ternary superconductors constitute a class of superconducting compounds with exceptional properties such as high transition temperatures (≅ 15.2 K), extremely high critical fields (H c2 >60 Tesla), and the coexistence of superconductivity and long-range magnetic order. This has generated great interest in the scientific community and resulted in a large number of experimental and theoretical investigations in which many new ternary compounds have been discovered. A review of some of the properties of these ternary compounds is presented with particular emphasis on the ternary molybdenum chalcogenides and the ternary rare earth transition metal tetraborides. The effect of partial substitution of a second metal atom to form pseudoternary compounds is examined as well as some of the proposed correlations between the superconducting transition temperature and the structural and electronic properties of the ternary superconductors

  3. Ternary fission

    Indian Academy of Sciences (India)

    2015-08-05

    Aug 5, 2015 ... We present the ternary fission of 252Cf and 236U within a three-cluster model as well as in a level density approach. The competition between collinear and equatorial geometry is studied by calculating the ternary fragmentation potential as a function of the angle between the lines joining the stationary ...

  4. Ternary fission

    Indian Academy of Sciences (India)

    respectively, which are expressed in MeV and taken from [12]. The ternary fragmentation potential between the three (spherical) fragments (referred to as PES), within the TCM [1–6], is defined as the sum of the total Coulomb potential, total nuclear potential, ℓ-dependent potential and the sum of the mass excesses of ternary.

  5. Ternary fission

    Indian Academy of Sciences (India)

    the energy minimization of all possible ternary breakups of a heavy radioactive nucleus. Further, within the TCM we have analysed the competition between different geometries as well as different positioning of the fragments. Also, an attempt was made to calculate the mass distribution of ternary fission process within the ...

  6. Investigating compositional effects of atomic layer deposition ternary dielectric Ti-Al-O on metal-insulator-semiconductor heterojunction capacitor structure for gate insulation of InAlN/GaN and AlGaN/GaN

    Energy Technology Data Exchange (ETDEWEB)

    Colon, Albert; Stan, Liliana; Divan, Ralu; Shi, Junxia

    2016-11-01

    Gate insulation/surface passivation in AlGaN/GaN and InAlN/GaN heterojunction field-effect transistors is a major concern for passivation of surface traps and reduction of gate leakage current. However, finding the most appropriate gate dielectric materials is challenging and often involves a compromise of the required properties such as dielectric constant, conduction/valence band-offsets, or thermal stability. Creating a ternary compound such as Ti-Al-O and tailoring its composition may result in a reasonably good gate material in terms of the said properties. To date, there is limited knowledge of the performance of ternary dielectric compounds on AlGaN/GaN and even less on InAlN/GaN. To approach this problem, the authors fabricated metal-insulator-semiconductor heterojunction (MISH) capacitors with ternary dielectrics Ti-Al-O of various compositions, deposited by atomic layer deposition (ALD). The film deposition was achieved by alternating cycles of TiO2 and Al2O3 using different ratios of ALD cycles. TiO2 was also deposited as a reference sample. The electrical characterization of the MISH capacitors shows an overall better performance of ternary compounds compared to the pure TiO2. The gate leakage current density decreases with increasing Al content, being similar to 2-3 orders of magnitude lower for a TiO2:Al2O3 cycle ratio of 2:1. Although the dielectric constant has the highest value of 79 for TiO2 and decreases with increasing the number of Al2O3 cycles, it is maintaining a relatively high value compared to an Al2O3 film. Capacitance voltage sweeps were also measured in order to characterize the interface trap density. A decreasing trend in the interface trap density was found while increasing Al content in the film. In conclusion, our study reveals that the desired high-kappa properties of TiO2 can be adequately maintained while improving other insulator performance factors. The ternary compounds may be an excellent choice as a gate material for both

  7. The structure of reconstructed chalcopyrite surfaces

    Science.gov (United States)

    Thinius, Sascha; Islam, Mazharul M.; Bredow, Thomas

    2018-03-01

    Chalcopyrite (CuFeS2) surfaces are of major interest for copper exploitation in aqueous solution, called leaching. Since leaching is a surface process knowledge of the surface structure, bonding pattern and oxidation states is important for improving the efficiency. At present such information is not available from experimental studies. Therefore a detailed computational study of chalcopyrite surfaces is performed. The structures of low-index stoichiometric chalcopyrite surfaces {hkl} h, k, l ∈ {0, 1, 2} have been studied with density functional theory (DFT) and global optimization strategies. We have applied ab initio molecular dynamics (MD) in combination with simulated annealing (SA) in order to explore possible reconstructions via a minima hopping (MH) algorithm. In almost all cases reconstruction involving substantial rearrangement has occurred accompanied by reduction of the surface energy. The analysis of the change in the coordination sphere and migration during reconstruction reveals that S-S dimers are formed on the surface. Further it was observed that metal atoms near the surface move toward the bulk forming metal alloys passivated by sulfur. The obtained surface energies of reconstructed surfaces are in the range of 0.53-0.95 J/m2.

  8. Development of interatomic potential of Ge(1- x - y )Si x Sn y ternary alloy semiconductors for classical lattice dynamics simulation

    Science.gov (United States)

    Tomita, Motohiro; Ogasawara, Masataka; Terada, Takuya; Watanabe, Takanobu

    2018-04-01

    We provide the parameters of Stillinger-Weber potentials for GeSiSn ternary mixed systems. These parameters can be used in molecular dynamics (MD) simulations to reproduce phonon properties and thermal conductivities. The phonon dispersion relation is derived from the dynamical structure factor, which is calculated by the space-time Fourier transform of atomic trajectories in an MD simulation. The phonon properties and thermal conductivities of GeSiSn ternary crystals calculated using these parameters mostly reproduced both the findings of previous experiments and earlier calculations made using MD simulations. The atomic composition dependence of these properties in GeSiSn ternary crystals obtained by previous studies (both experimental and theoretical) and the calculated data were almost exactly reproduced by our proposed parameters. Moreover, the results of the MD simulation agree with the previous calculations made using a time-independent phonon Boltzmann transport equation with complicated scattering mechanisms. These scattering mechanisms are very important in complicated nanostructures, as they allow the heat-transfer properties to be more accurately calculated by MD simulations. This work enables us to predict the phonon- and heat-related properties of bulk group IV alloys, especially ternary alloys.

  9. Electron microscope investigations of activated chalcopyrite particles via the FLSmidth® ROL process

    DEFF Research Database (Denmark)

    Karcz, Adam Paul; Damø, Anne Juul; Illerup, Jytte Boll

    2017-01-01

    in surface passivation problems associated with atmospheric leaching, this process is typically able to achieve copper recoveries exceeding 95% in 6 h. An important factor contributing to this extraordinary process performance is a mineral preconditioning step (the focus of this study), which uses between 0.......1 and 5 mol percent of copper (II) to dope the lattice and thereby “activate” chalcopyrite. Since lattice restructuring can have such a dramatic influence on semiconductor reactivity, the associated physico-chemical phenomena are worth studying. In this regard, we investigate the relationship between...... insights into the impact of applying chemical activation as a pretreatment for mechanochemical processes....

  10. Ternary fission

    International Nuclear Information System (INIS)

    Wagemans, C.

    1991-01-01

    Since its discovery in 1946, light (charged) particle accompanied fission (ternary fission) has been extensively studied, for spontaneous as well as for induced fission reactions. The reason for this interest was twofold: the ternary particles being emitted in space and time close to the scission point were expected to supply information on the scission point configuration and the ternary fission process was an important source of helium, tritium, and hydrogen production in nuclear reactors, for which data were requested by the nuclear industry. Significant experimental progress has been realized with the advent of high-resolution detectors, powerful multiparameter data acquisition systems, and intense neutron and photon beams. As far as theory is concerned, the trajectory calculations (in which scission point parameters are deduced from the experimental observations) have been very much improved. An attempt was made to explain ternary particle emission in terms of a Plateau-Rayleigh hydrodynamical instability of a relatively long cylindrical neck or cylindrical nucleus. New results have also been obtained on the so-called open-quotes trueclose quotes ternary fission (fission in three about-equal fragments). The spontaneous emission of charged particles has also clearly been demonstrated in recent years. This chapter discusses the main characteristics of ternary fission, theoretical models, light particle emission probabilities, the dependence of the emission probabilities on experimental variables, light particle energy distributions, light particle angular distributions, correlations between light particle accompanied fission observables, open-quotes trueclose quotes ternary fission, and spontaneous emission of heavy ions. 143 refs., 18 figs., 8 tabs

  11. Effect of amino acids on bioleaching of chalcopyrite ore by ...

    African Journals Online (AJOL)

    Amino acids seem to play a major role during bioleaching of chalcopyrite ore by Thiobacillus ferrooxidans. Efficiency of microbial leaching of chalcopyrite by T. ferrooxidans was investigated in the presence of L-aspartic acid, L-glutamic acid, L-histidine and L-serine. The bioleaching of copper ion (Cu2+) from the low grade ...

  12. Ternary systems

    International Nuclear Information System (INIS)

    Kagan, D.N.; Hubberstey, P.; Barker, M.G.

    1985-01-01

    The paper reviews the experimental and theoretical studies carried out on multicomponent alkali metal systems. Solid-liquid phase equilibria studies are mainly concerned with the systems Na-K-Rb and Na-K-Cs, and data on the liquidus temperatures in these systems are presented. The thermodynamic properties of the ternary Na-K-Cs eutectic system have been determined experimentally, and the enthalpy, heat capacity and excess functions of the alloy are given. An analysis of calculational methods used in determining thermodynamic functions of ternary liquid metals systems is described. Finally, data are tabulated for the density, compressibility, saturated vapour pressure, viscosity and thermal conductivity of the ternary Na-K-Cs eutectic system. (UK)

  13. Epitaxial growth of chalcopyrite CuInS2 films on GaAs (001) substrates by evaporation method with elemental sources

    International Nuclear Information System (INIS)

    Nozomu, Tsuboi; Satoshi, Kobayash; Nozomu, Tsuboi; Takashi, Tamogami

    2010-01-01

    Full text : Ternary chalcopyrite semiconductor CuInS 2 is one of the potential candidates for absorber layers in high-efficiency thin film solar cells due to its direct bandgap Eg of 1.5 eV, which matches with solar spectrum. However, CuInS 2 solar cells face the problem of lower solar conversion efficiency compared with Cu(InGa)Se 2 solar cells. Investigation of fundamental properties of CuInS 2 films is necessary to understand key issues for solar cell performance. Although in bulk CuInS 2 is known to crystallize into chalcopyrite (CH) structure, in thin film other structures such as Cu-Au (CA) and sphalerite (SP) structures may coexist. It was reported epitaxial growth of slightly Cu-rich CuInS 2 films with c-axis orientated CA only and/or with a mixture of a- and c-axes orientated CH structures on GaP (001) at substrate temperature of 500 degrees using the conventional evaporation method with three elemental sources. Successful growth of epitaxial CH structured CuInS 2 were observed for films grown on GaP at 570 degrees with slightly Cu-rich composition. In this paper, CuInS 2 films with various [Cu]/[In] ratios are grown on GaAs(001) substrates, and the composition range in terms of the [Cu]/[In] ratio where epitaxial films with CH structure grow and the structural qualities of the films are discussed in comparison with those on GaP substrates. Films with various ratios of [Cu]/[In]=0.8 ≤1.9 are grown at 500 degrees and 570 degrees using the evaporation system described in our previous reports. Regardless of the substrate temperature, noticeable X-ray diffraction (XRD) peaks of CH structured CuInS 2 phase are observed in slightly Cu-rich films. However, reflection high energy electron diffraction (RHEED) patterns of the slightly Cu-rich films grown at 570 degrees exhibit noticeable spots not only due to the CH structure but also due to the CA structure. The amount of the CA structure is considered to be small because of the absence of the XRD peaks of the CA

  14. From Large-Scale Synthesis to Lighting Device Applications of Ternary I-III-VI Semiconductor Nanocrystals: Inspiring Greener Material Emitters.

    Science.gov (United States)

    Chen, Bingkun; Pradhan, Narayan; Zhong, Haizheng

    2018-01-18

    Quantum dots with fabulous size-dependent and color-tunable emissions remained as one of the most exciting inventories in nanomaterials for the last 3 decades. Even though a large number of such dot nanocrystals were developed, CdSe still remained as unbeatable and highly trusted lighting nanocrystals. Beyond these, the ternary I-III-VI family of nanocrystals emerged as the most widely accepted greener materials with efficient emissions tunable in visible as well as NIR spectral windows. These bring the high possibility of their implementation as lighting materials acceptable to the community and also to the environment. Keeping these in mind, in this Perspective, the latest developments of ternary I-III-VI nanocrystals from their large-scale synthesis to device applications are presented. Incorporating ZnS, tuning the composition, mixing with other nanocrystals, and doping with Mn ions, light-emitting devices of single color as well as for generating white light emissions are also discussed. In addition, the future prospects of these materials in lighting applications are also proposed.

  15. Raman spectroscopic study of some chalcopyrite-xanthate flotation products

    CSIR Research Space (South Africa)

    Andreev, GN

    2003-12-16

    Full Text Available of normal vibrations of the corresponding individual compounds. The latter facilitated the Raman spectroscopic elucidation of the reaction products formed on the chalcopyrite surface in real industrial flotation conditions with a sodium isopropyl xanthate...

  16. Processes for chalcopyrite-based solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Lux-Steiner, M.C.; Ennaoui, A.; Fischer, C.-H.; Jaeger-Waldau, A.; Klaer, J.; Klenk, R.; Koenenkamp, R.; Matthes, T.; Scheer, R.; Siebentritt, S.; Weidinger, A. [Hahn-Meitner-Institut Berlin GmbH (Germany)

    2000-02-21

    This contribution deals with the investigations of chalcopyrite solar cells. Main attention is paid to absorber materials with band gaps larger than 1.5 eV. Besides the different efforts to modify and optimise stoichiometric CuInS{sub 2} films, novel deposition technologies for CuGaSe{sub 2} films and buffer layers as well as alternative buffer layers were studied and compared. With ZnSe as alternative buffer layer on Cu(InGa)(S,Se){sub 2} absorbers developed by SSI Camarillo and Siemens Solar, Munich, total area efficiencies up to 13.7% and active area efficiencies up to 15.7% could be reached, respectively. For CuInS{sub 2} two important results were achieved. The efficiency of Cu-poor CuInS{sub 2} cells could be increased to 8.3%. Standard Cu-rich prepared devices led to a new record efficiency of 12.5%. (orig.)

  17. Magnetic exchange interactions in Mn doped ZnSnAs{sub 2} chalcopyrite

    Energy Technology Data Exchange (ETDEWEB)

    Bouhani-Benziane, H.; Sahnoun, O. [Laboratoire de Physique Quantique de la Matière et Modélisation Mathématique (LPQ3M), University of Mascara (Algeria); Sahnoun, M., E-mail: sahnoun_cum@yahoo.fr [Laboratoire de Physique Quantique de la Matière et Modélisation Mathématique (LPQ3M), University of Mascara (Algeria); Department of Chemistry, University of Fribourg (Switzerland); Driz, M. [Laboratoire de Sciences des Matériaux (LSM), University of Sidi Bel Abbes (Algeria); Daul, C. [Department of Chemistry, University of Fribourg (Switzerland)

    2015-12-15

    Accurate ab initio full-potential augmented plane wave (FP-LAPW) electronic calculations within generalized gradient approximation have been performed for Mn doped ZnSnAs{sub 2} chalcopyrites, focusing on their electronic and magnetic properties as a function of the geometry related to low Mn-impurity concentration and the spin magnetic alignment (i.e., ferromagnetic vs antiferromagnetic). As expected, Mn is found to be a source of holes and localized magnetic moments of about 4 µ{sub B} per Mn atom are calculated which are sufficiently large. The defect calculations are firstly performed by replacing a single cation (namely Zn and Sn) with a single Mn atom in the pure chalcopyrite ZnSnAs{sub 2} supercell, and their corresponding formation energies show that the substitution of a Sn atom (rather than Zn) by Mn is strongly favored. Thereafter, a comparison of total energy differences between ferromagnetic (FM) and antiferromagnetic (AFM) are given. Surprisingly, the exchange interaction between a Mn pairs is found to oscillate with the distance between them. Consequently, the AFM alignment is energetically favored in Mn-doped ZnSnAs{sub 2} compounds, except for low impurity concentration associated with lower distances between neighboring Mn impurities, in this case the stabilization of FM increases. Moreover, the ferromagnetic alignment in the Mn-doped ZnSnAs{sub 2} systems behaves half-metallic; the valence band for majority spin orientation is partially filled while there is a gap in the density of states for the minority spin orientation. This semiconducting gap of ~1 eV opened up in the minority channel and is due to the large bonding–antibonding splitting from the p–d hybridization. Our findings suggest that the Mn-doped ZnSnAs{sub 2} chalcopyrites could be a different class of ferromagnetic semiconductors. - Highlights: • ab initio calculations were performed on Mn doped ZnSnAs{sub 2} chalcopyrite. • Substitution of a Sn atom (rather than Zn) by Mn

  18. Design of ternary clocked adiabatic static random access memory

    International Nuclear Information System (INIS)

    Wang Pengjun; Mei Fengna

    2011-01-01

    Based on multi-valued logic, adiabatic circuits and the structure of ternary static random access memory (SRAM), a design scheme of a novel ternary clocked adiabatic SRAM is presented. The scheme adopts bootstrapped NMOS transistors, and an address decoder, a storage cell and a sense amplifier are charged and discharged in the adiabatic way, so the charges stored in the large switch capacitance of word lines, bit lines and the address decoder can be effectively restored to achieve energy recovery during reading and writing of ternary signals. The PSPICE simulation results indicate that the ternary clocked adiabatic SRAM has a correct logic function and low power consumption. Compared with ternary conventional SRAM, the average power consumption of the ternary adiabatic SRAM saves up to 68% in the same conditions. (semiconductor integrated circuits)

  19. Electrochemical dissolution of chalcopyrite studied by voltammetry of immobilized microparticles

    Czech Academy of Sciences Publication Activity Database

    Pikna, L.; Lux, L.; Grygar, Tomáš

    2006-01-01

    Roč. 60, č. 4 (2006), s. 293-296 ISSN 0366-6352 Grant - others:VEGA(SK) No1/1108/04; APVT(SK) No20-009404 Institutional research plan: CEZ:AV0Z40320502 Keywords : chalcopyrite * cyclic voltammetry Subject RIV: CA - Inorganic Chemistry Impact factor: 0.360, year: 2006

  20. Effect of amino acids on bioleaching of chalcopyrite ore by ...

    African Journals Online (AJOL)

    Diptajeet

    2012-01-26

    Jan 26, 2012 ... long leach time and usually poor yield, limit the practical application of microbiological leaching of chalcopyrite ore. (Cordoba et al., 2008).Previous studies have shown that metal dissolution process from sulphidic ores by T. ferrooxidans can be increased in the presence of some amino acids (Groudev and ...

  1. The role of catalyst in the passivation of chalcopyrite during leaching

    OpenAIRE

    SOGHRA SALEHI; mohammad noaparast; seied ziaodin shafaie

    2017-01-01

    In this work, we present as investigation of chalcopyrite leaching under different leach conditions for how liquidation and surface of chalcopyrite study using Scanning Electron Microscopy (SEM) to determine the composition of the passivation layer in the surface of chalcopyrite. The study of chalcopyrite dissolution were in H2SO4 solution systems at pH of 1.2, with 5% chalcopyrite concentrate in redox potential of 460 mV at 90°C. The tests were directed to study on the leaching of chalcopyri...

  2. Characterizations of Some Semi magnetic Chalcopyrite Compounds

    International Nuclear Information System (INIS)

    Farrag, A.A.A.

    2012-01-01

    Cd 1-x Zn x Se (x=0, 0.5 and 1) and Cd 0.5 Zn 0.5 X 0.02 Se (X= Mn, Fe and Co) semiconductor and semi magnetic semiconductor compounds were prepared in the bulk form by melt quenching technique in ice water. Thin films of thickness 300 nm have been deposited on ultra cleaned soda lime glass substrates, at room temperature by thermal evaporation technique. The structural, optical and electrical properties of Cd 1-x Zn x Se (x=0, 0.5 and 1) and Cd 0.5 Zn 0.5 X 0.02 Se (X= Mn, Fe and Co) thin film samples have been studied. ESR and magnetic properties of Cd 0.5 Zn 0.5 X 0.02 Se (X= Mn, Fe and Co) powder samples also have been studied. The structural properties of Cd 1-x Zn x Se (x=0, 0.5 and 1) and Cd 0.5 Zn 0.5 X 0.02 Se (X= Mn, Fe and Co) thin film and powder samples have been investigated by using X-ray diffraction (XRD) technique. The crystal structure, lattice parameters, grain size, micro strain and dislocation density were determined from the X- ray diffraction patterns of the investigated samples. The optical properties of the investigated thin film samples were studied. Transmittance and reflectance were measured in wavelength range from 400 nm to 2500 nm and used to calculate the optical constants like absorption coefficient, refractive index and optical band gap. The obtained values of the optical band gap illustrated that the films exhibit direct band gap. The analysis of the obtained values of the refractive index yielded the high frequency dielectric constant and other optical dispersion parameters. The photon energy dependence of the relaxation time, dissipation factor and optical conductivity of the investigated thin film samples were studied also. The temperature dependence of dc conductivity for the investigated thin films was studied in temperature range from 300 K to 420 K. The obtained results showed that there are two different conduction mechanisms with two different values of activation energy in the defined temperature range. The temperature

  3. Effect of microwave-assisted heating on chalcopyrite leaching of kinetics, interface temperature and surface energy

    Directory of Open Access Journals (Sweden)

    Tong Wen

    Full Text Available The microwave-assisted leaching was a new approach to intensify the copper recovery from chalcopyrite by hydrometallurgy. In this work, the effect of microwave-assisted heating on chalcopyrite leaching of kinetics, interfacial reaction temperature and surface energy were investigated. The activation energy of chalcopyrite leaching was affected indistinctively by the microwave-assisted heating (39.1 kJ/mol compared with the conventional heating (43.9 kJ/mol. However, the boiling point of the leaching system increased through microwave-assisted heating. Because of the improved boiling point and the selective heating of microwave, the interfacial reaction temperature increased significantly, which gave rise to the increase of the leaching recovery of copper. Moreover, the surface energy of the chalcopyrite through microwave-assisted heating was also enhanced, which was beneficial to strengthen the leaching of chalcopyrite. Keywords: Microwave-assisted heating, Chalcopyrite, Leaching kinetics, Interface temperature, Surface energy

  4. Influence of chalcopyrite structure on their leaching by sodium nitrate in sulphuric acid

    Directory of Open Access Journals (Sweden)

    Miroslav Sokić

    2014-03-01

    Full Text Available During the chalcopyrite leaching by sodium nitrate and sulfuric acid solution, leaching rate decreases with increasing the time and a part of chalcopyrite mineral grains remains in the leach residue. In chalcopyrite concentrate, 95.5 % of chalcopyrite mineral occurs as in liberated grains, and the rest is in association with gangue minerals, which is very favorably from the aspect of hydrometallurgical treatment. Complex forms, like impregnations and complex intergrowths, do not exist. After experiments carried out, leaching of copper achieved 84 % at temperature 80 o C and time 240 min. In the all leach residues, 97 % chalcopyrite mineral grains occur as liberated with highly corroded surfaces. Therefore, the structural assembly of chalcopyrite grains is favorable and no reason to reduce the leaching rate in the final stage of reaction. Reason for this is elemental sulfur, which was formed during the reaction, precipitated at the particle surfaces, and slowed down the leaching rate in the final stage of leaching process.

  5. Dual effects of sodium sulfide on the flotation behavior of chalcopyrite: I. Effect of pulp potential

    Science.gov (United States)

    Taheri, Bijan; Abdollahy, Mahmoud; Tonkaboni, Sied Ziaedin Shafaei; Javadian, Soheyla; Yarahmadi, Mohammadreza

    2014-05-01

    This study explores the flotation behavior of chalcopyrite in the presence of different concentrations of sodium sulfide (Na2S·9H2O) at pH 12 under controlled potential conditions. It was observed that the flotation of chalcopyrite is not depressed completely when the pulp potential is low, even at high concentrations of sodium sulfide, i.e., 10-1-10-2 mol/L. However, a partial and controlled oxidation of pulp does enhance the effectiveness of sodium sulfide on the depression of chalcopyrite. Characterization of the chalcopyrite particle surface by X-ray photoelectron spectroscopy allowed the identification of hydrophilic and hydrophobic surface species, which are responsible for the depression and flotation of chalcopyrite. Changes in pulp potential were found to be an effective float controlling parameter, by which Na2S can be used to initiate or depress the flotation behavior of chalcopyrite.

  6. Ternary Silver Halide Nanocrystals.

    Science.gov (United States)

    Abeyweera, Sasitha C; Rasamani, Kowsalya D; Sun, Yugang

    2017-07-18

    Nanocrystalline silver halides (AgX) such as AgCl, AgBr, and AgI, a class of semiconductor materials with characteristics of both direct and indirect band gaps, represent the most crucial components in traditional photographic processing. The nanocrystal surfaces provide sensitivity specks that can turn into metallic silver, forming an invisible latent image, upon exposure to light. The photographic processing implies that the AgX nanoparticles possess unique properties. First, pristine AgX nanoparticles absorb light only at low efficiency to convert surface AgX into tiny clusters of silver atoms. Second, AgX nanoparticles represent an excellent class of materials to capture electrons efficiently. Third, small metallic silver clusters can catalyze the reduction of AgX nanoparticles to Ag nanoparticles in the presence of mild reducing reagents, known as self-catalytic reduction. These properties indicate that AgX nanoparticles can be partially converted to metallic silver with high precision, leading to the formation of hybrid AgX/Ag nanoparticles. The nanosized metallic Ag usually exhibit intense absorption bands in the visible spectral region due to their strong surface plasmon resonances, which make the AgX/Ag nanoparticles a class of promising visible-light-driven photocatalysts for environmental remediation and CO 2 reduction. Despite the less attention paid to their ability of capturing electrons, AgX nanoparticles might be a class of ideal electron shuttle materials to bridge light absorbers and catalysts on which electrons can drive chemical transformations. In this Account, we focus on ternary silver halide alloy (TSHA) nanoparticles, containing two types of halide ions, which increase the composition complexity of the silver halide nanoparticles. Interdiffusion of halide ions between two types of AgX at elevated temperatures has been developed for fabricating ternary silver halide alloy crystals, such as silver chlorobromide optical fibers for infrared

  7. Binary and ternary systems

    International Nuclear Information System (INIS)

    Petrov, D.A.

    1986-01-01

    Conditions for thermodynamical equilibrium in binary and ternary systems are considered. Main types of binary and ternary system phase diagrams are sequently constructed on the basis of general regularities on the character of transition from one equilibria to others. New statements on equilibrium line direction in the diagram triple points and their isothermal cross sections are developed. New represenations on equilibria in case of monovariant curve minimum and maximum on three-phase equilibrium formation in ternary system are introduced

  8. Design of ternary low-power Domino JKL flip—flop and its application

    International Nuclear Information System (INIS)

    Wang Pengjun; Yang Qiankun; Zheng Xuesong

    2012-01-01

    By researching the ternary flip—flop and the adiabatic Domino circuit, a novel design of low-power ternary Domino JKL flip—flop on the switch level is proposed. First, the switch-level structure of the ternary adiabatic Domino JKL flip—flop is derived according to the switch-signal theory and its truth table. Then the ternary loop operation circuit and ternary reverse loop operation circuit are achieved by employing the ternary JKL flip—flop. Finally, the circuit is simulated by using the Spice tool and the results show that the logic function is correct. The energy consumption of the ternary adiabatic Domino JKL flip—flop is 69% less than its conventional Domino counterpart. (semiconductor integrated circuits)

  9. Surface modifications of chalcopyrite CuInS2 thin films for photochatodes in photoelectrochemical water splitting under sunlight irradiation

    Science.gov (United States)

    Gunawan; Haris, A.; Widiyandari, H.; Septina, W.; Ikeda, S.

    2017-02-01

    Copper chalcopyrite semiconductors include a wide range of compounds that are of interest for photoelectrochemical water splitting which enables them to be used as photochatodes for H2 generation. Among them, CuInS2 is one of the most important materials due to its optimum band gap energy for sunlight absorption. In the present study, we investigated the application of CuInS2 fabricated by electrodeposition as photochatodes for water splitting. Thin film of CuInS2 chalcopyrite was formed on Mo-coated glass substrate by stacked electrodeposition of copper and indium followed by sulfurization under H2S flow. The films worked as a H2 liberation electrode under cathodic polarization from a solution containing Na2SO4 after loading Pt deposits on the film. Introduction of an n-type CdS layer by chemical bath deposition on the CuInS2 surface before the Pt loading resulted appreciable improvements of H2 liberation efficiency and a higher photocurrent onset potential. Moreover, the use of In2S3 layer as an alternative n-type layer to the CdS significantly improved the H2 liberation performance: the CuInS2 film modified with In2S3 and Pt deposits worked as an efficient photocathode for photoelectrochemical water splitting.

  10. The role of catalyst in the passivation of chalcopyrite during leaching

    Directory of Open Access Journals (Sweden)

    SOGHRA SALEHI

    2017-06-01

    Full Text Available In this work, we present as investigation of chalcopyrite leaching under different leach conditions for how liquidation and surface of chalcopyrite study using Scanning Electron Microscopy (SEM to determine the composition of the passivation layer in the surface of chalcopyrite. The study of chalcopyrite dissolution were in H2SO4 solution systems at pH of 1.2, with 5% chalcopyrite concentrate in redox potential of 460 mV at 90°C. The tests were directed to study on the leaching of chalcopyrite in ferric sulfate solution to extract copper with adding pyrite, silver and silver coated pyrite. In these approaches, achieved recoveries were different. The results showed that, in the present of pyrite, the presence of the elemental sulfur layer formed around the chalcopyrite particles which hindered the complete dissolution of copper in chalcopyrite. Also, in the presence of silver, no commercial process has been developed which successfully as a catalyst to recover copper from chalcopyrite. Because, the precipitation of argentojarosite, which forms during the leaching process, limits the availability of silver ion in solution which may act as a catalyst. But syndicate of silver and pyrite to form of silver coated pyrite, causes dissolution increase. However, in the presence of the pyrite coated by silver, leaching was very rapid for the duration of the test, and complete copper extraction was achieved within 10 hours.

  11. A stochastic model of solid state thin film deposition: Application to chalcopyrite growth

    Directory of Open Access Journals (Sweden)

    Robert J. Lovelett

    2016-04-01

    Full Text Available Developing high fidelity quantitative models of solid state reaction systems can be challenging, especially in deposition systems where, in addition to the multiple competing processes occurring simultaneously, the solid interacts with its atmosphere. In this work, we develop a model for the growth of a thin solid film where species from the atmosphere adsorb, diffuse, and react with the film. The model is mesoscale and describes an entire film with thickness on the order of microns. Because it is stochastic, the model allows us to examine inhomogeneities and agglomerations that would be impossible to characterize with deterministic methods. We demonstrate the modeling approach with the example of chalcopyrite Cu(InGa(SeS2 thin film growth via precursor reaction, which is a common industrial method for fabricating thin film photovoltaic modules. The model is used to understand how and why through-film variation in the composition of Cu(InGa(SeS2 thin films arises and persists. We believe that the model will be valuable as an effective quantitative description of many other materials systems used in semiconductors, energy storage, and other fast-growing industries.

  12. Co-Bioleaching of Chalcopyrite and Silver-Bearing Bornite in a Mixed Moderately Thermophilic Culture

    Directory of Open Access Journals (Sweden)

    Congren Yang

    2017-12-01

    Full Text Available Chalcopyrite and bornite are two important copper minerals, and they often coexist. In this study, the co-bioleaching of chalcopyrite and silver-bearing bornite by mixed moderately thermophilic culture at 50 °C was investigated. The bioleaching results show that the extraction percentage of Cu for co-bioleaching of chalcopyrite (Ccp and silver-bearing bornite (Bn (Ccp/Bn = 3:1 was 94.6%. Compared to bioleaching of chalcopyrite or silver-bearing bornite alone, the Cu extraction percentage was greatly enhanced when they were bioleached together. The leaching residues were characterized by X-ray diffraction (XRD and X-ray photoelectron spectroscopy (XPS. Silver-bearing bornite dissolved preferentially compared to chalcopyrite, due to galvanic interactions. Simultaneously, Ag+ was released from the silver-bearing bornite into solution. Ag2S formed on the surface because Cu and Fe in the chalcopyrite were replaced by Ag+, accelerating chalcopyrite dissolution and enrichment of Ag on the surface of the chalcopyrite.

  13. Galvanic enhancement for high pressure leaching of chalcopyrite

    Directory of Open Access Journals (Sweden)

    Kim D.H.

    2016-01-01

    Full Text Available This study was conducted to evaluate the galvanic enhancement of the pressure oxidation (POX leaching of a chalcopyrite/chalcocite concentrate, which is believed to take place via a redox reaction. Cu recoveries of >90% could be achieved during POX leaching of this chalcopyrite/chalcocite concentrate at 200°C and 0.7 MPa initial oxygen pressure within 2h in a pressure reactor lined with titanium, which were 18-28% higher than for the same leaching using the teflon liner. A slow heating time seems to produce more sulphur coating, reducing the leaching performance, yielding much lower Cu recovery when the teflon lining was used, although this does not greatly affect the other case when the reactor was lined with titanium. The introduction of an electronic conductor, in this case the titanium surface, is believed to enhance this redox process, in which the oxidation of copper minerals and sulphur to sulphate at the anodic sites (mineral surface encountered during POX leaching takes place simultaneously with the reversible oxidation/reduction of the Fe2+/Fe3+couple and oxygen reduction on titanium.

  14. Recent Developments in Chalcopyrite Solar Cell and Module Technologies

    Science.gov (United States)

    Ishizuka, Shogo; Komaki, Hironori; Yoshiyama, Takashi; Mizukoshi, Kazuyuki; Yamada, Akimasa; Niki, Shigeru

    Chalcopyrite Cu(In, Ga)Se2(CIGS) and related compounds belong to the semiconducting I-III-VI2 materials family and are most promising thin film solar cells which have demonstrated up to 20% cell efficiencies and over 15% module efficiencies to date. Many CIGS companies in EU, US, and Japan have started several ten MW/year scale commercial production and have announced to increase their production capacities further within a couple of years. In this review, recent developments in highly efficient CIGS module technologies and issues to be solved for further development are discussed. Recent progress in the development of reliable alkali incorporation control techniques which is required to demonstrate high cell efficiencies from flexible CIGS cells fabricated on alkali-free substrates is also introduced. The mechanism behind the beneficial effects of alkali doping into CIGS absorber layers is also discussed.

  15. Theoretical band alignment in an intermediate band chalcopyrite based material

    Science.gov (United States)

    Castellanos Águila, J. E.; Palacios, P.; Conesa, J. C.; Arriaga, J.; Wahnón, P.

    2017-12-01

    Band alignment is key to enhance the performance of heterojunction for chalcopyrite thin film solar cells. In this paper we report ab initio calculations of the electronic structures of CuGaS2:Cr with various Cr compositions, CuAlSe2 and ZnSe and the band alignment between their interfaces. We use density functional theory and the more accurate self-consistent GW scheme to obtain improved bulk band-gaps and band offsets. Band alignments of the interfacial region for CuGaS2:Cr/CuAlSe2 and CuGaS2:Cr/ZnSe systems were aligned with respect of an average electrostatic potential. Our results are in good agreement with experimental values for the bulk band-gaps. These theoretical band alignments show a characteristic staggered band alignment for the design of heterojunction devices in photovoltaic applications.

  16. Optimization of the use of carbon paste electrodes (CPE for electrochemical study of the chalcopyrite

    Directory of Open Access Journals (Sweden)

    Daniela G. Horta

    2009-01-01

    Full Text Available The use of carbon paste electrodes (CPE of mineral sulfides can be useful for electrochemical studies to overcome problems by using massive ones. Using CPE-chalcopyrite some variables were electrochemically evaluated. These variables were: (i the atmosphere of preparation (air or argon of CPE and elapsed time till its use; (ii scan rate for voltammetric measurements and (iii chalcopyrite concentration in the CPE. Based on cyclic voltammetry, open-circuit potential and electrochemical impedance results the recommendations are: oxygen-free atmosphere to prepare and kept the CPE until around two ours, scan rates from 10 to 40 mV s-1, and chalcopyrite concentrations > 20%.

  17. Einstein relation in compound semiconductors and their nanostructures

    CERN Document Server

    Bhattacharya, Sitangshu

    2008-01-01

    Deals with the Einstein relation in compound semiconductors and their nanostructures. This book considers materials such as nonlinear optical, III-V, ternary, quaternary, II-VI, IV-VI, Bismuth, stressed compounds, quantum wells, quantum wires, nipi structures, carbon nanotubes, heavily doped semiconductors, and inversion layers.

  18. Schottky contact analysis of photovoltaic chalcopyrite thin film absorbers

    International Nuclear Information System (INIS)

    Schlenker, E.; Mertens, V.; Parisi, J.; Reineke-Koch, R.; Koentges, M.

    2007-01-01

    Current-voltage and capacitance-voltage measurements serve to analyze thermally evaporated Al Schottky contacts on Cu(In, Ga)Se 2 based photovoltaic thin film devices, either taken as grown or etched in a bromine-methanol solution. The characteristics of the Schottky contacts on the as-grown films give evidence for some dielectric layer developing between the metal and the semiconductor. Etching the semiconductor surface prior to evaporation of the Al front contact yields a pure metal-semiconductor behavior, including effects that can be attributed to an additional diode at the Mo contact. Simulations confirm the experimental results

  19. Computational Study of Chalcopyrite Semiconductors and Their Non-Linear Optical Properties

    National Research Council Canada - National Science Library

    Lambrecht, Walter R

    2007-01-01

    ... (Including cation antisites, cation and anion vacancies) and CdGeAs2; a study of the feasibility of nonciritical phase matching and associated nonlinear optical parameters in CdSiP2 and CdSIAs2...

  20. Analysis of a data base of chalcopyrite semiconductors in 2 and 3 ...

    African Journals Online (AJOL)

    The analysis of the data is currently, in the statisticians, the object of a true phenomenon of mode, characterized at the same time by the passion and the rejection. To determine the characteristics of a whole of data is obviously not an end in itself, but this lapse of memory is unfortunate because the type of data available ...

  1. Electronic structure of epitaxial chalcopyrite surfaces and interfaces for photovoltaics

    International Nuclear Information System (INIS)

    Hofmann, Andreas

    2012-01-01

    This thesis constitutes a comprehensive study of the surface physics of epitaxial CuInSe 2 films. It comprises analyses of the surface morphology and reconstruction, electronic band structure as well as hetero-junctions relevant to photovoltaic applications. Therefore, especially the aspect of stoichiometry variation from the CuInSe 2 to the copper-deficient defect phases was considered. Preparation and analysis was completely performed under ultra-high vacuum conditions in order to ensure the investigation of well-defined samples free of contaminants. For some of the analysis techniques, single-crystalline samples are indispensable: They allow for the determination of surface periodicity by low-energy electron diffraction (LEED). In combination with concentration depth profiling by angle-resolved x-ray photoemission, to types of surface reconstructions could be distinguished for the near-stoichiometric CuInSe 2 (112) surface. In the copper-rich case, it is stabilized by Cu In anti-site defects and on the indium-rich side by 2 V Cu defects, as predicted by surface total energy calculations by Jaffe and Zunger. Both configurations correspond to a c(4 x 2) reconstruction of the zinc blende type (111) surface. For the defect compound CuIn 3 Se 5 , a sphalerite order of the surface was found, which points at a weakening or absence of the chalcopyrite order in the bulk of the material. The unusual stability of the (112) surface could also be proven by comparison with the reconstruction and surface order of (001) and (220) surfaces. The results from surface analysis were used to measure the valence band structure of the epitaxial samples by synchrotron-based angle-resolved photoelectron spectroscopy. The CuInSe 2 (001) surface gives access to the high symmetry directions Γ-T and Γ-N of momentum space. By contrasting the data obtained for the stoichiometric surface with the copper-poor defect compound, a reduction of the valence band dispersion and a broadening of

  2. Synthesis of nanoparticle emulsion collector HNP and its application in microfine chalcopyrite flotation

    Science.gov (United States)

    He, G. C.; Ding, J.; Huang, C. H.; Kang, Q.

    2018-01-01

    Hydrophobic polystyrene nanoparticles bearing thiazole groups named HNP were used as collectors to improve recovery of microfine chalcopyrite in flotation. HNP adsorbs onto microfine particles selectively, which were modified hydrophobically to induce flotation effectively. Particle size and scanning electron microscope analysis for HNP show that HNP is a spherical nano particles with small size, uniform distribution and good dispersion. Infrared spectrum analysis for HNP proved that functional monomer 2-mercapto styrene acrylic thiazole was bonded chemically onto styrene. Flotation test results indicate that HNP is the right collector of chalcopyrite. Especially, the recovery of chalcopyrite is higher than 95% in neutral and acid media. FTIR results reveal that the flotation selectivity of collector HNP is due to strong chemical absorption onto chalcopyrite surface. Zeta potential analysis shows that the zeta potential of chalcopyrite decreased more quickly after interaction with HNP with the increase of pulp pH value, confirming that collector HNP is an anionic collector. Scanning electron microscope conform that HNP has good selective adsorption on chalcopyrite.

  3. The electrochemical oxidation of chalcopyrite in ammoniacal solutions

    Science.gov (United States)

    Warren, G. W.; Wadsworth, M. E.

    1984-06-01

    The anodic dissolution of chalcopyrite in ammoniacal solutions was investigated using electrochemical methods. At low overvoltages, the formation of a copper deficient sulfide layer, Cu1-xFeS2 through a charge transfer reaction is proposed based upon the dependence of the rest or open circuit potential on solution composition and the presence of a Tafel region of appropriate slope. In addition, a current peak that occurs at 10-4 A/cm2 is a function of the square root of the voltage scanning speed and is explained in terms of a charge transfer reaction. At larger overvoltages, constant potential experiments and mass balances performed at various anodic potentials indicate that the dissolution is consistent with the overall reaction, CuFeS2 + 4NH3 + 9OH- = Cu(NH3){4/+2} + Fe(OH)3 + S2O{3/=} + 3H2O + 9e -, although some copper may be released to solution in the cuprous state and some ferrous iron has been identified in the product film. Current vs time data taken during constant potential experiments were found to obey a linear rate relationship. This was interpreted in terms of the formation of a layer of constant thickness which is corroded at the outer interface at the same rate it is formed at the inner interface.. The model proposed is typical of the corrosion of some metals. An examination of the polarization curves shows the dissolution reaction to be first order with respect to [OH-]. The lack of dependence on [Cu2+] indicates that the catalytic effect of cupric ion during oxygen pressure leaching is related only to the cathodic reduction of O2 in agreement with the results of previous investigations.

  4. Semiconductor statistics

    CERN Document Server

    Blakemore, J S

    1987-01-01

    In-depth exploration of the implications of carrier populations and Fermi energies examines distribution of electrons in energy bands and impurity levels of semiconductors. Also: kinetics of semiconductors containing excess carriers, particularly in terms of trapping, excitation, and recombination.

  5. Selective Attachment of Leptospirillum ferrooxidans for Separation of Chalcopyrite and Pyrite through Bio-Flotation

    Directory of Open Access Journals (Sweden)

    Belinda Bleeze

    2018-02-01

    Full Text Available The replacement of depressants used in sulfide mineral beneficiation, with bacteria and their metabolites, promises to reduce the environmental impact left by the mining industry. In this study, the attachment of Leptospirillum ferrooxidans, L.f, to chalcopyrite and pyrite was investigated through Scanning Electron Microscopy (SEM. The impact of selective attachment, bacterial growth conditions, and extracellular polymeric substances (EPS was investigated through bio-flotation. L.f exhibits selective attachment to pyrite between 0 h and 168 h exposure via an indirect contact mechanism. Separation of chalcopyrite from pyrite was achieved through exposing the minerals for 72 h with an L.f culture grown on either HH media, chalcopyrite, or pyrite. The results produced 80.4, 43.4, and 47.4% recovery of chalcopyrite, respectively. However, EPS supernatant extracted from L.f grown on chalcopyrite, conditioned for 48 h, provided the best separation efficiency by the selective depression of pyrite resulting in 95.8% Cu recovery. Polysaccharide-rich EPS selectively attaches to pyrite within 48 h, depressing its floatability and ensuring successful separation with a PIPX collector.

  6. Chalcopyrite Thin Film Materials for Photoelectrochemical Hydrogen Evolution from Water under Sunlight

    Directory of Open Access Journals (Sweden)

    Hiroyuki Kaneko

    2015-07-01

    Full Text Available Copper chalcopyrite is a promising candidate for a photocathode material for photoelectrochemical (PEC water splitting because of its high half-cell solar-to-hydrogen conversion efficiency (HC-STH, relatively simple and low-cost preparation process, and chemical stability. This paper reviews recent advances in copper chalcopyrite photocathodes. The PEC properties of copper chalcopyrite photocathodes have improved fairly rapidly: HC-STH values of 0.25% and 8.5% in 2012 and 2015, respectively. On the other hand, the onset potential remains insufficient, owing to the shallow valence band maximum mainly consisting of Cu 3d orbitals. In order to improve the onset potential, we explored substituting Cu for Ag and investigate the PEC properties of silver gallium selenide (AGSe thin film photocathodes for varying compositions, film growth atmospheres, and surfaces. The modified AGSe photocathodes showed a higher onset potential than copper chalcopyrite photocathodes. It was demonstrated that element substitution of copper chalcopyrite can help to achieve more efficient PEC water splitting.

  7. Semiconductor physics

    CERN Document Server

    Böer, Karl W

    2018-01-01

    This handbook gives a complete survey of the important topics and results in semiconductor physics. It addresses every fundamental principle and most research topics and areas of application in the field of semiconductor physics. Comprehensive information is provided on crystalline bulk and low-dimensional as well as amporphous semiconductors, including optical, transport, and dynamic properties.

  8. Ternary System with Controlled Structure: A New Strategy toward Efficient Organic Photovoltaics.

    Science.gov (United States)

    Cheng, Pei; Wang, Rui; Zhu, Jingshuai; Huang, Wenchao; Chang, Sheng-Yung; Meng, Lei; Sun, Pengyu; Cheng, Hao-Wen; Qin, Meng; Zhu, Chenhui; Zhan, Xiaowei; Yang, Yang

    2018-02-01

    Recently, a new type of active layer with a ternary system has been developed to further enhance the performance of binary system organic photovoltaics (OPV). In the ternary OPV, almost all active layers are formed by simple ternary blend in solution, which eventually leads to the disordered bulk heterojunction (BHJ) structure after a spin-coating process. There are two main restrictions in this disordered BHJ structure to obtain higher performance OPV. One is the isolated second donor or acceptor domains. The other is the invalid metal-semiconductor contact. Herein, the concept and design of donor/acceptor/acceptor ternary OPV with more controlled structure (C-ternary) is reported. The C-ternary OPV is fabricated by a sequential solution process, in which the second acceptor and donor/acceptor binary blend are sequentially spin-coated. After the device optimization, the power conversion efficiencies (PCEs) of all OPV with C-ternary are enhanced by 14-21% relative to those with the simple ternary blend; the best PCEs are 10.7 and 11.0% for fullerene-based and fullerene-free solar cells, respectively. Moreover, the averaged PCE value of 10.4% for fullerene-free solar cell measured in this study is in great agreement with the certified one of 10.32% obtained from Newport Corporation. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Galvanic Interaction between Chalcopyrite and Pyrite with Low Alloy and High Carbon Chromium Steel Ball

    Directory of Open Access Journals (Sweden)

    Asghar Azizi

    2013-01-01

    Full Text Available This study was aimed to investigate the galvanic interaction between pyrite and chalcopyrite with two types of grinding media (low alloy and high carbon chromium steel ball in grinding of a porphyry copper sulphide ore. Results indicated that injection of different gases into mill altered the oxidation-reduction environment during grinding. High carbon chromium steel ball under nitrogen gas has the lowest galvanic current, and low alloy steel ball under oxygen gas had the highest galvanic current. Also, results showed that the media is anodic relative to pyrite and chalcopyrite, and therefore pyrite or chalcopyrite with a higher rest potential acted as the cathode, whilst the grinding media with a lower rest potential acted as the anode, when they are electrochemically contacted. It was also found that low alloy steel under oxygen produced the highest amount of EDTA extractable iron in the slurry, whilst high carbon chromium steel under nitrogen atmosphere led to the lowest amount.

  10. Combined DFT and XPS investigation of iodine anions adsorption on the sulfur terminated (001) chalcopyrite surface

    Energy Technology Data Exchange (ETDEWEB)

    Li, Kui, E-mail: likui9606@stu.xjtu.edu.cn [School of Nuclear Science and Technology, Xi’an Jiaotong University, Xi’an 710049 (China); Zhao, Yaolin, E-mail: zhaoyaolin@mail.xjtu.edu.cn [School of Nuclear Science and Technology, Xi’an Jiaotong University, Xi’an 710049 (China); Zhang, Peng, E-mail: zp32@qq.com [Sino Shaanxi Nuclear Industry Group, Xi’an 710100 (China); He, Chaohui, E-mail: hechaohui@mail.xjtu.edu.cn [School of Nuclear Science and Technology, Xi’an Jiaotong University, Xi’an 710049 (China); Deng, Jia, E-mail: djkokocase@stu.xjtu.edu.cn [School of Nuclear Science and Technology, Xi’an Jiaotong University, Xi’an 710049 (China); Ding, Shujiang, E-mail: dingsj@mail.xjtu.edu.cn [Department of Applied Chemistry, School of Science, Xi’an Jiaotong University, Xi’an 710049 (China); Shi, Weiqun, E-mail: shiwq@ihep.ac.cn [Key Laboratory of Nuclear Radiation and Nuclear Energy Technology and Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)

    2016-12-30

    Highlights: • Metal surface sites of (001)-S surface of chalcopyrite show significant chemical affinity to iodide and iodate. • The energetically favorable active site is copper for iodide adsorption and iron for iodate adsorption, respectively. • Iodate undergoes a dissociative adsorption on the copper site of chalcopyrite surface. - Abstract: The adsorption of iodine anions (iodide and iodate) on the sulfur terminated (001) chalcopyrite surface has been systematically investigated combining first-principles calculations based on density functional theory (DFT) with X-ray photoelectron spectroscopy (XPS) measurements. Based on the total energy calculations and geometric optimization, the thermodynamically preferred site was copper atom for iodide adsorption and iron atom for iodate adsorption, respectively. In the case of Cu site mode, the iodate underwent a dissociative adsorption, where one I−O bond of iodate ion was broken and the dissociative oxygen atom adsorbed on the adjacent sulphur site. Projected density of states (PDOS) analysis further clarified the interaction mechanism between active sites of chalcopyrite surface and adsorbates. In addition, full-range XPS spectra qualitatively revealed the presence of iodine on chalcopyrite surface. High resolution XPS spectra of the I 3d peaks after adsorption verified the chemical environment of iodine. The binding energies of 618.8 eV and 623.5 eV for I 3d{sub 5/2} peaks unveiled that the adsorption of iodide and iodate ions on copper-iron sulfide minerals was the result of formation of low solubility metal iodides precipitate. Also two I 3d peaks with low intensity around 618 eV and 630 eV might be related to the inorganic reduction of iodate to iodide by reducing S{sup 2−} ion of chalcopyrite.

  11. Structural characteristics of chalcopyrite from a Cu(Au) ore deposit in the Carajas Mineral Province, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Aparecida Ribeiro, Andreza; Quintao Lima, Diana; Anderson Duarte, Helio; Murad, Enver [ICEx, UFMG, Departamento de Quimica (Brazil); Pereira, Marcio Cesar, E-mail: mcpqui@yahoo.com.br [Universidade Federal dos Vales do Jequitinhonha e Mucuri, Instituto de Ciencia e Tecnologia (Brazil); Tadeu de Freitas Suita, Marcos [UFOP, Departamento de Geologia (Brazil); Ardisson, Jose Domingos [Centro de Desenvolvimento da Tecnologia Nuclear (Brazil); Fabris, Jose Domingos [Universidade Federal dos Vales do Jequitinhonha e Mucuri, UFVJM (Brazil)

    2011-11-15

    Moessbauer spectra and X-ray diffraction data show a chalcopyrite from the Cristalino Cu(Au) deposit in the Carajas Mineral Province in northern Brazil to consist of a single, tetragonal phase. This is in stark contrast to a previously described chalcopyrite from the Camaqua copper mine in southern Brazil, obviously reflecting differences in mineral (and thus ore deposit) genesis.

  12. The influence of mechanical activation of chalcopyrite on the selective leaching of copper by sulphuric acid

    Directory of Open Access Journals (Sweden)

    Achimovičová, M.

    2006-01-01

    Full Text Available In this paper chalcopyrite, CuFeS2, has been selective leached by H2SO4 as leaching agent (170 g/dm3 in procedure of hydrometallurgical production of copper. Mechanical activation of the chalcopyrite resulted in mechanochemical surface oxidation as well as in the mineral surface and bulk disordering. Furthermore, the formation of agglomerates during grinding was also occured. Surface changes of the samples using infrared spectroscopy and scanning electron microscopy methods were investigated before and after leaching. The leaching rate, specific surface area, structural disorder as well as copper extraction increased with the mechanical activation of mineral.

  13. Kinetics of chalcopyrite galvanic leaching using sulfate media at the low temperature in the GalvanoxTM process

    Directory of Open Access Journals (Sweden)

    Soghra Salehi

    2016-12-01

    Full Text Available In this research work, the dissolution of chalcopyrite was investigated under atmospheric pressure, with sulfate media at low temperatures, in 30°C to 50°C. In the galvanic interaction between chalcopyrite and pyrite, pyrite is used as a leaching catalyst. Effects of different parameters such as temperature, stirring speed, pyrite to chalcopyrite ratio, particle size, and solution potential were examined. Results showed that maximum copper recovery in low temperature was achieved after 24 hours, under the following condition: stirring speed of 800 rpm, pyrite to chalcopyrite ratio 4, solution potential 440 mV, temperature 50°C, and particle size of -38 microns. In addition, kinetic studies indicated that chalcopyrite dissolution with pyrite followed the shrinking core model, and the reaction was controlled by the surface reaction. Activation energy (Ea was calculated as 88 kJ/mol.

  14. Mott type variable range hopping conduction and magnetoresistance in p-type CuIn3Te5 semiconductor compound

    Science.gov (United States)

    Essaleh, L.; Wasim, S. M.; Marín, G.; Rincón, C.; Amhil, S.; Galibert, J.

    2017-07-01

    Variable range hopping (VRH) conduction of Mott type for a constant and non-vanishing density of states at the Fermi level is observed over a wide range of temperature between 45 and 210 K in the ordered defect compound CuIn3Te5 (CIT135). For this type of electrical conduction at a very high temperature, not reported before in elemental, II-VI, and I-III-VI2 compound semiconductors, we employed three different methods to analyze the data and to confirm this behavior. The occurrence of VRH at very high temperatures is explained as due to the presence of the electrically inactive ( InCu+2 + 2 VCu -1) donor-acceptor defect pairs in CIT135. This defect-pair partially annihilates the shallow acceptor defect state Cu vacancy, which is responsible for the activated electrical conductivity observed in p-type ternary I-III-VI2 chalcopyrite compounds in the temperature range of liquid nitrogen. In such conditions, the only acceptor level available for electrical conduction in CIT135 is a deep acceptor state whose activation energy is about 200 meV and cannot be activated below about 200 K. Hence, the VRH conduction mechanism dominates the electrical properties of this material up to about 200 K. The study of the temperature and magnetic field dependence of the magnetoresistance (MR) up to 27 T is made by taking into consideration different theoretical models. To explain the negative MR at lower fields, the theory based on quantum interference is used. At higher magnetic fields, the MR becomes positive and is explained with the model based on the shrinkage of the wave function.

  15. UV photoelectron yield spectroscopy of chalcopyrite structure Cu-In-Se thin films

    International Nuclear Information System (INIS)

    Kohiki, Shigemi; Nishitani, Mikihiko; Negami, Takayuki; Wada, Takahiro; Monjushiro, Hideaki; Watanabe, Iwao; Yokoyama, Yu

    1994-01-01

    Surface-sensitive UV photoelectron yield spectroscopy was employed to study electron acceptor levels at surfaces of chalcopyrite structure Cu-In-Se thin films. Surface Fermi level pinning was observed for Cu-rich films. Shallow acceptor levels ascribable to defects Cu In and V Cu were observed for near-stoichiometric and In-rich films respectively. (orig.)

  16. Semiconductor spintronics

    CERN Document Server

    Xia, Jianbai; Chang, Kai

    2012-01-01

    Semiconductor Spintronics, as an emerging research discipline and an important advanced field in physics, has developed quickly and obtained fruitful results in recent decades. This volume is the first monograph summarizing the physical foundation and the experimental results obtained in this field. With the culmination of the authors' extensive working experiences, this book presents the developing history of semiconductor spintronics, its basic concepts and theories, experimental results, and the prospected future development. This unique book intends to provide a systematic and modern foundation for semiconductor spintronics aimed at researchers, professors, post-doctorates, and graduate students, and to help them master the overall knowledge of spintronics.

  17. Macroporous Semiconductors

    Directory of Open Access Journals (Sweden)

    Helmut Föll

    2010-05-01

    Full Text Available Pores in single crystalline semiconductors come in many forms (e.g., pore sizes from 2 nm to > 10 µm; morphologies from perfect pore crystal to fractal and exhibit many unique properties directly or as nanocompounds if the pores are filled. The various kinds of pores obtained in semiconductors like Ge, Si, III-V, and II-VI compound semiconductors are systematically reviewed, emphasizing macropores. Essentials of pore formation mechanisms will be discussed, focusing on differences and some open questions but in particular on common properties. Possible applications of porous semiconductors, including for example high explosives, high efficiency electrodes for Li ion batteries, drug delivery systems, solar cells, thermoelectric elements and many novel electronic, optical or sensor devices, will be introduced and discussed.

  18. Semiconductor heterojunctions

    CERN Document Server

    Sharma, B L

    1974-01-01

    Semiconductor Heterojunctions investigates various aspects of semiconductor heterojunctions. Topics covered include the theory of heterojunctions and their energy band profiles, electrical and optoelectronic properties, and methods of preparation. A number of heterojunction devices are also considered, from photovoltaic converters to photodiodes, transistors, and injection lasers.Comprised of eight chapters, this volume begins with an overview of the theory of heterojunctions and a discussion on abrupt isotype and anisotype heterojunctions, along with graded heterojunctions. The reader is then

  19. Ternary alloys based on ii-vi semiconductor compounds

    CERN Document Server

    Tomashyk, Vasyl; Shcherbak, Larysa

    2013-01-01

    Phase Equilibria in the Systems Based on ZnSSystems Based on ZnSeSystems Based on ZnTeSystems Based on CdSSystem Based on CdSeSystem Based on CdTeSystems Based on HgSSystems Based on HgSeSystems Based on HgTeIndexReferences appear at the end of each chapter.

  20. Ternary alloys based on II-VI semiconductor compounds

    CERN Document Server

    Tomashyk, Vasyl; Shcherbak, Larysa

    2013-01-01

    Phase Equilibria in the Systems Based on ZnSSystems Based on ZnSeSystems Based on ZnTeSystems Based on CdSSystem Based on CdSeSystem Based on CdTeSystems Based on HgSSystems Based on HgSeSystems Based on HgTeIndexReferences appear at the end of each chapter.

  1. Grain-size distributions and grain boundaries of chalcopyrite-type thin films

    International Nuclear Information System (INIS)

    Abou-Ras, D.; Schorr, S.; Schock, H.W.

    2007-01-01

    CuInSe 2 , CuGaSe 2 , Cu(In,Ga)Se 2 and CuInS 2 thin-film solar absorbers in completed solar cells were studied in cross section by means of electronbackscatter diffraction. From the data acquired, grain-size distributions were extracted, and also the most frequent grain boundaries were determined. The grain-size distributions of all chalcopyrite-type thin films studied can be described well by lognormal distribution functions. The most frequent grainboundary types in these thin films are 60 - left angle 221 right angle tet and 71 - left angle 110 right angle tet (near) Σ3 twin boundaries. These results can be related directly to the importance of {112} tet planes during the topotactical growth of chalcopyrite-type thin films. Based on energetic considerations, it is assumed that the most frequent twin boundaries exhibit a 180 - left angle 221 right angle tet constellation. (orig.)

  2. Solution-processed In2S3 buffer layer for chalcopyrite thin film solar cells

    OpenAIRE

    Wang Lan; Lin Xianzhong; Ennaoui Ahmed; Wolf Christian; Lux-Steiner Martha Ch.; Klenk Reiner

    2016-01-01

    We report a route to deposit In2S3 thin films from air-stable, low-cost molecular precursor inks for Cd-free buffer layers in chalcopyrite-based thin film solar cells. Different precursor compositions and processing conditions were studied to define a reproducible and robust process. By adjusting the ink properties, this method can be applied in different printing and coating techniques. Here we report on two techniques, namely spin-coating ...

  3. Copper solvent extraction from chalcopyrite concentrate acid leach solutions by LIX 984

    OpenAIRE

    Elamari K.; Jdid E.A.; Blazy P.

    2006-01-01

    Copper production from ores or sulphide concentrates is classically realized by pyrometallurgical route. In this study, hydrometallurgical treatment of a copper sulphide concentrate, provided by Hajar Mine (ONA-Group, Morocco), was tested by using a mixture of nitric and hexafluorosilicic acids. Copper is present in the solid product as chalcopyrite and its amount is 28.1 % by weight. Leaching stage allows to dissolve more than 90% of copper witch is accompanied, in the same averages, by Zn a...

  4. Diffusion in copper sulphides. An experimental study of chalcocite, chalcopyrite and bornite

    Energy Technology Data Exchange (ETDEWEB)

    Berger, R.; Bucur, R.V. [Uppsala Univ. (Sweden). Inst. of Chemistry

    1996-01-01

    Diffusion measurements on three copper-containing sulphides have been performed by an electrochemical potentiometric method. Chalcocite (Cu{sub 2}S), Chalcopyrite (CuFeS{sub 2}) and Bornite (Cu{sub 5}FeS{sub 4}) were synthesized and fully characterized by X-ray diffraction. The diffusivities were measured on compacted powders yielding both the chemical and the component diffusion coefficients in the temperature range 5-50 C. The chemical diffusion coefficients found were: for Chalcocite 38.7*exp (-5600/T), for Chalcopyrite 15.4*exp(-6000/T) and for Bornite 14.4*exp(-4900/T). The diffusion coefficient for Chalcocite is in good agreement with values found previously, and a reasonable agreement is also found for Chalcopyrite and Bornite when our data are compared with values acquired at much higher temperatures with a different technique. The activation energies (here on a Kelvin scale) are remarkably similar for the three sulfides, considering that their relative errors are of a 10% magnitude, which indicates that the bonding strengths and the diffusion mechanisms are similar. The chemical diffusion coefficients which enter the empirical Fick`s diffusion laws that describe concentration changes, are of the order of exp(-8) to exp (-7) cm{sup 2}/s at room temperature. Such values bring the ion mobilities near values found for solid state `fast ion conductors`, used as electrolytes at elevated temperatures. 17 refs, 8 figs, 5 tabs.

  5. Diffusion in copper sulphides. An experimental study of chalcocite, chalcopyrite and bornite

    International Nuclear Information System (INIS)

    Berger, R.; Bucur, R.V.

    1996-01-01

    Diffusion measurements on three copper-containing sulphides have been performed by an electrochemical potentiometric method. Chalcocite (Cu 2 S), Chalcopyrite (CuFeS 2 ) and Bornite (Cu 5 FeS 4 ) were synthesized and fully characterized by X-ray diffraction. The diffusivities were measured on compacted powders yielding both the chemical and the component diffusion coefficients in the temperature range 5-50 C. The chemical diffusion coefficients found were: for Chalcocite 38.7*exp (-5600/T), for Chalcopyrite 15.4*exp(-6000/T) and for Bornite 14.4*exp(-4900/T). The diffusion coefficient for Chalcocite is in good agreement with values found previously, and a reasonable agreement is also found for Chalcopyrite and Bornite when our data are compared with values acquired at much higher temperatures with a different technique. The activation energies (here on a Kelvin scale) are remarkably similar for the three sulfides, considering that their relative errors are of a 10% magnitude, which indicates that the bonding strengths and the diffusion mechanisms are similar. The chemical diffusion coefficients which enter the empirical Fick's diffusion laws that describe concentration changes, are of the order of exp(-8) to exp (-7) cm 2 /s at room temperature. Such values bring the ion mobilities near values found for solid state 'fast ion conductors', used as electrolytes at elevated temperatures. 17 refs, 8 figs, 5 tabs

  6. Synthesis of Novel Ether Thionocarbamates and Study on Their Flotation Performance for Chalcopyrite

    Directory of Open Access Journals (Sweden)

    Gang Zhao

    2016-09-01

    Full Text Available Novel ether thionocarbamates, O-butoxy isopropyl-N-ethoxycarbonyl thionocarbamate (BIPECTC and O-(2-butoxy-1-methylethoxy isopropyl-N-ethoxycarbonyl thionocarbamate (BMIPECTC, were synthesized in this study. Their collecting efficiencies in the flotation of chalcopyrite were investigated using flotation tests, adsorption measurements, ultraviolet spectra (UV and Fourier transform-infrared spectroscopy (FT-IR and density functional theory (DFT calculations. The synthesized ether thionocarbamates showed better frothing properties than methyl-isobutyl-carbinol (MIBC and stronger affinity to chalcopyrite compared with O-isopropyl-N-ethyl thionocarbamate (IPETC and O-isobutyl-N-ethoxycarbonyl thionocarbamate (IBECTC. UV spectra analysis showed that the ether thionocarbamates react with Cu2+, with the exception of Fe2+, Ni2+, Zn2+ and Pb2+. Additionally, it was further confirmed by FTIR spectra that a chemical reaction occurs between copper ion and BIPECTC and BMIPECTC. The adsorption capacity measurements revealed that chalcopyrite exhibits good adsorption ability for ether thionocarbamates at an approximate pH of 8–10, which agrees with the flotation tests. The quantum chemistry calculation results indicated that the ether thionocarbamates exhibit stronger collecting ability for copper mineral in terms of frontier molecular orbital analysis, binding model simulation with copper ions and the molecular hydrophobicity compared with IPETC and IBECTC. The computational results are in very good agreement with the experimental results.

  7. Ternary Weighted Function and Beurling Ternary Banach Algebra l1ω(S

    Directory of Open Access Journals (Sweden)

    Mehdi Dehghanian

    2011-01-01

    Full Text Available Let S be a ternary semigroup. In this paper, we introduce our notation and prove some elementary properties of a ternary weight function ω on S. Also, we make ternary weighted algebra l1ω(S and show that l1ω(S is a ternary Banach algebra.

  8. Nanostructured Semiconductor Electrodes for Solar Energy Conversion and Innovations in Undergraduate Chemical Lab Curriculum

    Science.gov (United States)

    Lee, Sudarat

    This dissertation presents the methodology and discussion of preparing nanostructured, high aspect ratio p-type phosphide-based binary and ternary semiconductors via "top-down" anodic etching, a process which creates nanostructures from a large parent entity, and "bottom-up" vapor-liquid-solid growth, a mechanism which builds up small clusters of molecules block-by-block. Such architecture is particularly useful for semiconducting materials with incompatible optical absorption depth and charge carrier diffusion length, as it not only relaxes the requirement for high-grade crystalline materials, but also increases the carrier collection efficiencies for photons with energy greater than or equal to the band gap. The main focus of this dissertation is to obtain nanostructured p-type phosphide semiconductors for photoelectrochemical (PEC) cell applications. Chapter II in the thesis describes a methodology for creating high-aspect ratio p-GaP that function as a photocathode under white light illumination. Gallium phosphide (GaP, band gap: 2.26 eV) is a suitable candidate for solar conversion and energy storage due to its ability to generate large photocurrent and photovoltage to drive fuel-forming reactions. Furthermore, the band edge positions of GaP can provide sufficient kinetics for the reduction of protons and carbon dioxide. The structure is prepared by anodic etching, and the resulting macroporous structures are subsequently doped with Zn by thermally driving in Zn from conformal ZnO films prepared by atomic layer deposition (ALD). The key finding of this work is a viable doping strategy involving ALD ZnO films for making functioning p-type GaP nanostructures. Chapter III compares the GaP nanowires grown from gold (Au) and tin (Sn) VLS catalysts in a benign solid sublimation growth scheme in terms of crystal structure and photoactivity. Sn is less noble than Au, allowing complete removal of Sn metal catalysts from the nanowires through wet chemical etching which

  9. Semiconductor electrochemistry

    CERN Document Server

    Memming, Rüdiger

    2015-01-01

    Providing both an introduction and an up-to-date survey of the entire field, this text captivates the reader with its clear style and inspiring, yet solid presentation. The significantly expanded second edition of this milestone work is supplemented by a completely new chapter on the hot topic of nanoparticles and includes the latest insights into the deposition of dye layers on semiconductor electrodes. In his monograph, the acknowledged expert Professor Memming primarily addresses physical and electrochemists, but materials scientists, physicists, and engineers dealing with semiconductor technology and its applications will also benefit greatly from the contents.

  10. Semiconductor statistics

    CERN Document Server

    Blakemore, J S

    1962-01-01

    Semiconductor Statistics presents statistics aimed at complementing existing books on the relationships between carrier densities and transport effects. The book is divided into two parts. Part I provides introductory material on the electron theory of solids, and then discusses carrier statistics for semiconductors in thermal equilibrium. Of course a solid cannot be in true thermodynamic equilibrium if any electrical current is passed; but when currents are reasonably small the distribution function is but little perturbed, and the carrier distribution for such a """"quasi-equilibrium"""" co

  11. Oxide semiconductors

    CERN Document Server

    Svensson, Bengt G; Jagadish, Chennupati

    2013-01-01

    Semiconductors and Semimetals has distinguished itself through the careful selection of well-known authors, editors, and contributors. Originally widely known as the ""Willardson and Beer"" Series, it has succeeded in publishing numerous landmark volumes and chapters. The series publishes timely, highly relevant volumes intended for long-term impact and reflecting the truly interdisciplinary nature of the field. The volumes in Semiconductors and Semimetals have been and will continue to be of great interest to physicists, chemists, materials scientists, and device engineers in academia, scient

  12. True ternary fission in 310126X

    International Nuclear Information System (INIS)

    Banupriya, B.; Vijayaraghavan, K.R.; Balasubramaniam, M.

    2015-01-01

    All possible combinations are minimized by the two dimensional minimization process and minimized with respect to neutron numbers and proton numbers of the fragments. Potential energy is low and Q - value is high at true ternary fission region. It shows that true ternary mode is the dominant mode in the ternary fission of superheavy nuclei. Also, the results show that the fragments with neutron magic numbers are the dominant one in the ternary fission of superheavy nuclei whereas the fragments with proton magic numbers are the dominant one in the ternary fission of heavy nuclei

  13. Semiconductor Detectors; Detectores de Semiconductores

    Energy Technology Data Exchange (ETDEWEB)

    Cortina, E.

    2007-07-01

    Particle detectors based on semiconductor materials are among the few devices used for particle detection that are available to the public at large. In fact we are surrounded by them in our daily lives: they are used in photoelectric cells for opening doors, in digital photographic and video camera, and in bar code readers at supermarket cash registers. (Author)

  14. Semiconductor Optics

    CERN Document Server

    Klingshirn, Claus F

    2012-01-01

    This updated and enlarged new edition of Semiconductor Optics provides an introduction to and an overview of semiconductor optics from the IR through the visible to the UV, including linear and nonlinear optical properties, dynamics, magneto and electrooptics, high-excitation effects and laser processes, some applications, experimental techniques and group theory. The mathematics is kept as elementary as possible, sufficient for an intuitive understanding of the experimental results and techniques treated. The subjects covered extend from physics to materials science and optoelectronics. Significantly updated chapters add coverage of current topics such as electron hole plasma, Bose condensation of excitons and meta materials. Over 120 problems, chapter introductions and a detailed index make it the key textbook for graduate students in physics. The mathematics is kept as elementary as possible, sufficient for an intuitive understanding of the experimental results and techniques treated. The subjects covered ...

  15. Semiconductor sensors

    International Nuclear Information System (INIS)

    Hartmann, Frank

    2011-01-01

    Semiconductor sensors have been around since the 1950s and today, every high energy physics experiment has one in its repertoire. In Lepton as well as Hadron colliders, silicon vertex and tracking detectors led to the most amazing physics and will continue doing so in the future. This contribution tries to depict the history of these devices exemplarily without being able to honor all important developments and installations. The current understanding of radiation damage mechanisms and recent R and D topics demonstrating the future challenges and possible technical solutions for the SLHC detectors are presented. Consequently semiconductor sensor candidates for an LHC upgrade and a future linear collider are also briefly introduced. The work presented here is a collage of the work of many individual silicon experts spread over several collaborations across the world.

  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. Ternary Fission Studies by Correlation Measurements with Ternary Particles

    Science.gov (United States)

    Mutterer, Manfred

    2011-10-01

    The rare ternary fission process has been studied mainly by inclusive measurements of the energy distributions and fractional yields of the light charged particles (LCPs) from fission, or by experiments on the angular and energy correlation between LCPs and fission fragments (FFs). The present contribution presents a brief overview of more elaborate correlation measurements that comprise the emission of neutrons and γ rays with LCPs and FFs, or the coincident registration of two LCPs. These measurements have permitted identification of new modes of particle-accompanied fission, such as the population of excited states in LCPs, the formation of neutron-unstable nuclei as short-lived intermediate LCPs, as well as the sequential decay of particle-unstable LCPs and quaternary fission. Furthermore, the neutron multiplicity numbers bar ν (A) and distributions of fragment masses A, measured for the ternary fission modes with various LCP isotopes, give a valuable hint of the role played by nuclear shell structure in the fission process near scission. Finally, two different hitherto unknown asymmetries in ternary α-particle emission with respect to the fission axis, called the TRI and ROT effect, were studied in fission reactions induced by polarised cold neutrons.

  18. Some new ternary linear codes

    Directory of Open Access Journals (Sweden)

    Rumen Daskalov

    2017-07-01

    Full Text Available Let an $[n,k,d]_q$ code be a linear code of length $n$, dimension $k$ and minimum Hamming distance $d$ over $GF(q$. One of the most important problems in coding theory is to construct codes with optimal minimum distances. In this paper 22 new ternary linear codes are presented. Two of them are optimal. All new codes improve the respective lower bounds in [11].

  19. Modelling of chalcopyrite oxidation reactions in the Outokumpu flash smelting process

    Energy Technology Data Exchange (ETDEWEB)

    Ahokainen, T.; Jokilaakso, A. [Helsinki Univ. of Technology, Otaniemi (Finland)

    1996-12-31

    A mathematical model for simulating oxidation reactions of chalcopyrite particles together with momentum, heat and mass transfer between particle and gas phase in a flash smelting furnace reaction shaft is presented. In simulation, the equations governing the gas flow are solved numerically with a commercial fluid flow package, Phoenics. The particle phase is introduced into the gas flow by a Particle Source In Cell (PSIC) - technique, where a number of discrete particles is tracked in a gas flow and the relevant source terms for momentum, mass, and heat transfer are added to the gas phase equations. The gas phase equations used are elliptic in nature and the fluid turbulence is described by the (k-{epsilon}) -model. Thermal gas phase radiation is simulated with a six-flux radiation model. The chemical reactions of concentrate particles are assumed to happen at two sharp interfaces, and a shrinking core model is applied to describe the mass transfer of chemical species through the reaction product layer. In a molten state, the oxygen consumption is controlled by a film penetration concept. The reacting concentrate particles are a mixture of chalcopyrite and silica. Also a certain amount of pure inert silica is fed to the process as flux. In the simulations the calculation domain includes the concentrate burner and a cylindrical reaction shaft of an industrial scale flash smelting furnace. Some examples about the simulations carried out by the combustion model are presented. (author)

  20. Thermophilic archaeal community succession and function change associated with the leaching rate in bioleaching of chalcopyrite.

    Science.gov (United States)

    Zhu, Wei; Xia, Jin-lan; Yang, Yi; Nie, Zhen-yuan; Peng, An-an; Liu, Hong-chang; Qiu, Guan-zhou

    2013-04-01

    The community succession and function change of thermophilic archaea Acidianus brierleyi, Metallosphaera sedula, Acidianus manzaensis and Sulfolobus metallicus were studied by denaturing gradient gel electrophoresis (DGGE) analysis of amplifying 16S rRNA genes fragments and real-time qPCR analysis of amplifying sulfur-oxidizing soxB gene associated with chalcopyrite bioleaching rate at different temperatures and initial pH values. The analysis results of the community succession indicated that temperature and initial pH value had a significant effect on the consortium, and S. metallicus was most sensitive to the environmental change, A. brierleyi showed the best adaptability and sulfur oxidation ability and predominated in various leaching systems. Meanwhile, the leaching rate of chalcopyrite closely related to the consortium function embodied by soxB gene, which could prove a desirable way for revealing microbial sulfur oxidation difference and tracking the function change of the consortium, and for optimizing the leaching parameters and improving the recovery of valuable metals. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. Flotation performances and surface properties of chalcopyrite with xanthate collector added before and after grinding

    Science.gov (United States)

    Peng, Huiqing; Wu, Di; Abdelmonem, Mohamed

    In this study, effects of the collector added before grinding and after grinding on the subsequent flotation and mineral surface properties were investigated. The pH was controlled at 10 during the grinding and flotation processes opened to the atmosphere. With enough amounts of sodium butyl xanthate addition, adding the collector before grinding recovered more chalcopyrite than adding it after grinding in single mineral flotation. The Eh of each ground pulp before and after conditioning were measured and it was found that adding collector before grinding obtained higher and relatively suitable pulp potential for chalcopyrite flotation. Particle size analyses of the flotation products indicate that the different flotation recoveries occurred due to the different flotation losses in fine particles (<20 μm). XPS analyses focused on the fine particles of flotation feedings and found that more carbon and oxygen, and less iron were remained on mineral surfaces when the collector was added before grinding, due to the higher collector adsorption capacity, larger free oxygen adsorbance and less iron oxide/hydroxide species.

  2. Polytetrafluoroethylene/TiO2 Composite Pellets as Sulfur Adsorbents for Pressure Oxidation Leaching of Chalcopyrite

    Science.gov (United States)

    Govindaiah, Patakamuri; Grundy, Mark; Guerra, Eduard; Choi, Yeonuk; Ye, Zhibin

    2015-04-01

    In this study, we report the use of polytetrafluoroethylene/titanium dioxide (PTFE/TiO2) composite pellets as sulfur adsorbents in the extraction of copper from chalcopyrite by pressure oxidation leaching. PTFE/TiO2 composites of various compositions were prepared by compression molding followed by pelletization. The mass percentage of TiO2 filler in the PTFE matrix was varied from 0 to 35 wt pct. With the use of the composite pellets, significant enhancements in copper leaching were observed, indicating their role as adsorbents for the adsorption of molten elemental sulfur. In particular, the enhancement in copper extraction was increasingly pronounced (from 75 to 89 pct) with the increase of the mass percentage of TiO2 in the composite pellets from 0 to 35 wt pct. This is reasoned to result from the loss of TiO2 domains from the pellet surface, which creates additional rough hydrophobic surface to better capture elemental sulfur. The composite pellet adsorbents show excellent reusability, with the performance well maintained for 10 leaching cycles. In addition, the effectiveness of composite adsorbents at different chalcopyrite pulp densities was also investigated.

  3. Oxidation mechanism of chalcopyrite revealed by X-ray photoelectron spectroscopy and first principles studies

    Science.gov (United States)

    Xiong, Xiaolu; Hua, Xiaoming; Zheng, Yongfei; Lu, Xionggang; Li, Shenggang; Cheng, Hongwei; Xu, Qian

    2018-01-01

    X-ray photoelectron spectroscopic (XPS) studies revealed that the iron site on the chalcopyrite (CuFeS2) surface was preferably oxidized to the Cu site when exposed to an oxidizing environment. Extensive density functional theory calculations were performed to investigate the surface structure of chalcopyrite and its reaction with both molecular oxygen (O2) and water. The adsorption and dissociation of a single O2 molecule, a single H2O molecule, as well as both molecules at the Fe and Cu sites on the CuFeS2 (001) surface were studied. Consistent with our experimental observation, the Fe site was found to be preferred for the adsorption and dissociation of O2 due to its lower energy barrier and greater exothermicity. The dissociation of H2O on the CuFeS2 (001) surface by itself was found to be unfavorable both thermodynamically and kinetically. However, the surface formed upon O2 dissociation was predicted to be much more reactive with H2O, which was attributed to favorable hydrogen transfer to the O site formed upon O2 dissociation to hydrogen transfer to the S site due to the much weaker Ssbnd H bond than the Osbnd H bond.

  4. Nearly Ternary Quadratic Higher Derivations on Non-Archimedean Ternary Banach Algebras: A Fixed Point Approach

    Directory of Open Access Journals (Sweden)

    M. Eshaghi Gordji

    2011-01-01

    Full Text Available We investigate the stability and superstability of ternary quadratic higher derivations in non-Archimedean ternary algebras by using a version of fixed point theorem via quadratic functional equation.

  5. 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)

  6. Ternary scandium and transition metals germanides

    International Nuclear Information System (INIS)

    Kotur, B.Ya.

    1992-01-01

    Brief review of data on phase diagram of ternary Sc-Me-Ge systems (Me-d - , f-transition element) is given. Isothermal sections at 870 and 1070 K of 17 ternary systems are plotted. Compositions and their structural characteristics are presented. Variability of crystal structure is typical for ternary scandium germanides: 70 compounds with the studied structure belong to 23 structural types. Ternary germanides isostructural to types of Sm 4 Ge 4 , ZrCrSi 2 , ZrNiAl, ScCeSi, TiNiSi U 4 Re 7 Si 6 145 compounds from 70 under investigation are mostly formed in studied systems

  7. Magnetic semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Bihler, Christoph

    2009-04-15

    In this thesis we investigated in detail the properties of Ga{sub 1-x}Mn{sub x}As, Ga{sub 1-x}Mn{sub x}P, and Ga{sub 1-x}Mn{sub x}N dilute magnetic semiconductor thin films with a focus on the magnetic anisotropy and the changes of their properties upon hydrogenation. We applied two complementary spectroscopic techniques to address the position of H in magnetic semiconductors: (i) Electron paramagnetic resonance, which provides direct information on the symmetry of the crystal field of the Mn{sup 2+} atoms and (ii) x-ray absorption fine structure analysis which allows to probe the local crystallographic neighborhood of the absorbing Mn atom via analysing the fine structure at the Mn K absorption edge. Finally, we discussed the obstacles that have to be overcome to achieve Curie temperatures above the current maximum in Ga{sub 1-x}Mn{sub x}As of 185 K. Here, we outlined in detail the generic problem of the formation of precipitates at the example of Ge:MN. (orig.)

  8. Power semiconductors

    CERN Document Server

    Kubát, M

    1984-01-01

    The book contains a summary of our knowledge of power semiconductor structures. It presents first a short historic introduction (Chap. I) as well as a brief selection of facts from solid state physics, in particular those related to power semiconductors (Chap. 2). The book deals with diode structures in Chap. 3. In addition to fundamental facts in pn-junction theory, the book covers mainly the important processes of power structures. It describes the emitter efficiency and function of microleaks (shunts). the p +p and n + n junctions, and in particular the recent theory of the pin, pvn and p1tn junctions, whose role appears to be decisive for the forward mode not only of diode structures but also of more complex ones. For power diode structures the reverse mode is the decisive factor in pn-junction breakdown theory. The presentation given here uses engineering features (the multiplication factor M and the experimentally detected laws for the volume and surface of crystals), which condenses the presentation an...

  9. Stability of Naturally Relevant Ternary Phases in the Cu–Sn–S system in Contact with an Aqueous Solution

    Directory of Open Access Journals (Sweden)

    Andrea Giaccherini

    2016-07-01

    Full Text Available A relevant research effort is devoted to the synthesis and characterization of phases belonging to the ternary system Cu–Sn–S, mainly for their possible applications in semiconductor technology. Among all ternary phases, kuramite, Cu3SnS4, mohite, Cu2SnS3, and Cu4Sn7S16 have attracted the highest interest. Numerous studies were carried out claiming for the description of new phases in the ternary compositional field. In this study, we revise the existing literature on this ternary system, with a special focus on the phases stable in a temperature range at 25 °C. The only two ternary phases observed in nature are mohite and kuramite. Their occurrence is described as very rare. A numerical modelling of the stable solid phases in contact with a water solution was underwent to define stability relationships of the relevant phases of the system. The numerical modelling of the Eh-pH diagrams was carried out through the phreeqc software with the lnll.dat thermodynamic database. Owing to the complexity of this task, the subsystems Cu–O–H, Sn–O–H, Cu–S–O–H and Sn–S–O–H were firstly considered. The first Pourbaix diagram for the two naturally relevant ternary phases is then proposed.

  10. Semiconductor Laser Measurements Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The Semiconductor Laser Measurements Laboratory is equipped to investigate and characterize the lasing properties of semiconductor diode lasers. Lasing features such...

  11. Examples of neutron diffraction texture analysis on one and the same chalcopyrite sample before and after experimental deformation

    International Nuclear Information System (INIS)

    Jansen, E.M.; Brokmeier, H.G.; Siemes, H.

    1994-01-01

    Natural chalcopyrite specimens from Mt. Isa, Australia were investigated by neutron diffraction texture analysis. The preferred orientation of the specimens consists of 3 main orientation components. After axial shortening at a temperature of 25 C the initial orientation components became weaker, a new component was detected. (orig.)

  12. Discovery of earth-abundant nitride semiconductors by computational screening and high-pressure synthesis

    OpenAIRE

    Hinuma, Yoyo; Hatakeyama, Taisuke; Kumagai, Yu; Burton, Lee A.; Sato, Hikaru; Muraba, Yoshinori; Iimura, Soshi; Hiramatsu, Hidenori; Tanaka, Isao; Hosono, Hideo; Oba, Fumiyasu

    2016-01-01

    Nitride semiconductors are attractive because they can be environmentally benign, comprised of abundant elements and possess favourable electronic properties. However, those currently commercialized are mostly limited to gallium nitride and its alloys, despite the rich composition space of nitrides. Here we report the screening of ternary zinc nitride semiconductors using first-principles calculations of electronic structure, stability and dopability. This approach identifies as-yet-unreporte...

  13. Enhanced Light Absorption in Fluorinated Ternary Small-Molecule Photovoltaics

    Energy Technology Data Exchange (ETDEWEB)

    Eastham, Nicholas D. [Department; Dudnik, Alexander S. [Department; Harutyunyan, Boris [Department; Aldrich, Thomas J. [Department; Leonardi, Matthew J. [Department; Manley, Eric F. [Department; Chemical; Butler, Melanie R. [Department; Harschneck, Tobias [Department; Ratner, Mark A. [Department; Chen, Lin X. [Department; Chemical; Bedzyk, Michael J. [Department; Department; Melkonyan, Ferdinand S. [Department; Facchetti, Antonio [Department; Chang, Robert P. H. [Department; Marks, Tobin J. [Department; Department

    2017-06-14

    Using small-molecule donor (SMD) semiconductors in organic photovoltaics (OPVs) has historically afforded lower power conversion efficiencies (PCEs) than their polymeric counterparts. The PCE difference is attributed to shorter conjugated backbones, resulting in reduced intermolecular interactions. Here, a new pair of SMDs is synthesized based on the diketopyrrolopyrrole-benzodithiophene-diketopyrrolopyrrole (BDT-DPP2) skeleton but having fluorinated and fluorinefree aromatic side-chain substituents. Ternary OPVs having varied ratios of the two SMDs with PC61BM as the acceptor exhibit tunable open-circuit voltages (Vocs) between 0.833 and 0.944 V due to a fluorination-induced shift in energy levels and the electronic “alloy” formed from the miscibility of the two SMDs. A 15% increase in PCE is observed at the optimal ternary SMD ratio, with the short-circuit current density (Jsc) significantly increased to 9.18 mA/cm2. The origin of Jsc enhancement is analyzed via charge generation, transport, and diffuse reflectance measurements, and is attributed to increased optical absorption arising from a maximum in film crystallinity at this SMD ratio, observed by grazing incidence wide-angle X-ray scattering.

  14. X-PEEM, XPS and ToF-SIMS characterisation of xanthate induced chalcopyrite flotation: Effect of pulp potential

    Science.gov (United States)

    Kalegowda, Yogesh; Chan, Yuet-Loy; Wei, Der-Hsin; Harmer, Sarah L.

    2015-05-01

    Synchrotron-based X-ray photoemission electron microscopy (X-PEEM), X-ray photo-electron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS) and ultraviolet visible spectroscopy were used to characterize the flotation behaviour of chalcopyrite with xanthate at different processing conditions. The flotation recovery of chalcopyrite decreased from 97% under oxidative conditions (Eh ~ 385 mV SHE, pH 4) to 41% at a reductive potential of - 100 mV SHE (at pH 9). X-PEEM images constructed from the metal L3 absorption edges were used to produce near-edge X-ray absorption fine structure (NEXAFS) spectra from regions of interest, allowing the variability in mineral surface chemistry of each mineral particle to be analysed, and the effect of pulp potential (Eh) on the flotation of chalcopyrite to be determined. XPS, ToF-SIMS and NEXAFS analyses of chalcopyrite particles at oxidative conditions show that the surface was mildly oxidised and covered with adsorbed molecular CuEX. The Cu 2p XPS and Cu L2,3 NEXAFS spectra were dominated by CuI species attributed to bulk chalcopyrite and adsorbed CuEX. At a reductive potential of - 100 mV SHE, an increase in concentration of CuI and FeIII oxides and hydroxides was observed. X-PEEM analysis was able to show the presence of a low percentage of CuII oxides (CuO or Cu(OH)2) with predominantly CuI oxide (Cu2O) which is not evident in Cu 2p XPS spectra.

  15. On Some Ternary LCD Codes

    OpenAIRE

    Darkunde, Nitin S.; Patil, Arunkumar R.

    2018-01-01

    The main aim of this paper is to study $LCD$ codes. Linear code with complementary dual($LCD$) are those codes which have their intersection with their dual code as $\\{0\\}$. In this paper we will give rather alternative proof of Massey's theorem\\cite{8}, which is one of the most important characterization of $LCD$ codes. Let $LCD[n,k]_3$ denote the maximum of possible values of $d$ among $[n,k,d]$ ternary $LCD$ codes. In \\cite{4}, authors have given upper bound on $LCD[n,k]_2$ and extended th...

  16. Solution-processed In2S3 buffer layer for chalcopyrite thin film solar cells

    Directory of Open Access Journals (Sweden)

    Wang Lan

    2016-01-01

    Full Text Available We report a route to deposit In2S3 thin films from air-stable, low-cost molecular precursor inks for Cd-free buffer layers in chalcopyrite-based thin film solar cells. Different precursor compositions and processing conditions were studied to define a reproducible and robust process. By adjusting the ink properties, this method can be applied in different printing and coating techniques. Here we report on two techniques, namely spin-coating and inkjet printing. Active area efficiencies of 12.8% and 12.2% have been achieved for In2S3-buffered solar cells respectively, matching the performance of CdS-buffered cells prepared with the same batch of absorbers.

  17. Solution-processed In2S3 buffer layer for chalcopyrite thin film solar cells

    Science.gov (United States)

    Wang, Lan; Lin, Xianzhong; Ennaoui, Ahmed; Wolf, Christian; Lux-Steiner, Martha Ch.; Klenk, Reiner

    2016-02-01

    We report a route to deposit In2S3 thin films from air-stable, low-cost molecular precursor inks for Cd-free buffer layers in chalcopyrite-based thin film solar cells. Different precursor compositions and processing conditions were studied to define a reproducible and robust process. By adjusting the ink properties, this method can be applied in different printing and coating techniques. Here we report on two techniques, namely spin-coating and inkjet printing. Active area efficiencies of 12.8% and 12.2% have been achieved for In2S3-buffered solar cells respectively, matching the performance of CdS-buffered cells prepared with the same batch of absorbers.

  18. Luminescent Colloidal Semiconductor Nanocrystals Containing Copper: Synthesis, Photophysics, and Applications.

    Science.gov (United States)

    Knowles, Kathryn E; Hartstein, Kimberly H; Kilburn, Troy B; Marchioro, Arianna; Nelson, Heidi D; Whitham, Patrick J; Gamelin, Daniel R

    2016-09-28

    Copper-doped semiconductors are classic phosphor materials that have been used in a variety of applications for many decades. Colloidal copper-doped semiconductor nanocrystals have recently attracted a great deal of interest because they combine the solution processability and spectral tunability of colloidal nanocrystals with the unique photoluminescence properties of copper-doped semiconductor phosphors. Although ternary and quaternary semiconductors containing copper, such as CuInS2 and Cu2ZnSnS4, have been studied primarily in the context of their photovoltaic applications, when synthesized as colloidal nanocrystals, these materials have photoluminescence properties that are remarkably similar to those of copper-doped semiconductor nanocrystals. This review focuses on the luminescent properties of colloidal copper-doped, copper-based, and related copper-containing semiconductor nanocrystals. Fundamental investigations into the luminescence of copper-containing colloidal nanocrystals are reviewed in the context of the well-established luminescence mechanisms of bulk copper-doped semiconductors and copper(I) molecular coordination complexes. The use of colloidal copper-containing nanocrystals in applications that take advantage of their luminescent properties, such as bioimaging, solid-state lighting, and luminescent solar concentrators, is also discussed.

  19. Description of the ternary system Cu-Ge-Te

    International Nuclear Information System (INIS)

    Dogguy, M.; Carcaly, C.; Rivet, J.; Flahaut, J.

    1977-01-01

    The Cu-Ge-Te ternary system has been studied by DTA and by crystallographic and metallographic analysis. The existence of a ternary compound Cu 2 GeTe 3 is demonstrated; this compound has a ternary incongruent melting point at 500 0 C. This ternary compound has a superstructure of a zinc blende type. The study shows the existence of five ternary eutectics. Two liquid-liquid miscibility gaps exist: the first is situated entirely in the ternary system; the second gives a monotectic region within the ternary system. (Auth.)

  20. Synthesis of ternary nitrides by mechanochemical alloying

    DEFF Research Database (Denmark)

    Jacobsen, C.J.H.; Zhu, J.J.; Lindelov, H.

    2002-01-01

    Ternary metal nitrides ( of general formula MxM'N-y(z)) attract considerable interest because of their special mechanical, electrical, magnetic, and catalytic properties. Usually they are prepared by ammonolysis of ternary oxides (MxM'O-y(m)) at elevated temperatures. We show that ternary...... nitrides by mechanochemical alloying of a binary transition metal nitride (MxN) with an elemental transition metal. In this way, we have been able to prepare Fe3Mo3N and Co3Mo3N by ball-milling of Mo2N with Fe and Co, respectively. The transformation sequence from the starting materials ( the binary...

  1. Performance Estimation for Lowpass Ternary Filters

    Directory of Open Access Journals (Sweden)

    O'Shea Peter

    2003-01-01

    Full Text Available Ternary filters have tap values limited to , , or . This restriction in tap values greatly simplifies the multipliers required by the filter, making ternary filters very well suited to hardware implementations. Because they incorporate coarse quantisation, their performance is typically limited by tap quantisation error. This paper derives formulae for estimating the achievable performance of lowpass ternary filters, thereby allowing the number of computationally intensive design iterations to be reduced. Motivated by practical communications systems requirements, the performance measure which is used is the worst-case stopband attenuation.

  2. All-optical symmetric ternary logic gate

    Science.gov (United States)

    Chattopadhyay, Tanay

    2010-09-01

    Symmetric ternary number (radix=3) has three logical states (1¯, 0, 1). It is very much useful in carry free arithmetical operation. Beside this, the logical operation using this type of number system is also effective in high speed computation and communication in multi-valued logic. In this literature all-optical circuits for three basic symmetrical ternary logical operations (inversion, MIN and MAX) are proposed and described. Numerical simulation verifies the theoretical model. In this present scheme the different ternary logical states are represented by different polarized state of light. Terahertz optical asymmetric demultiplexer (TOAD) based interferometric switch has been used categorically in this manuscript.

  3. Ternary fission and cluster radioactivities

    CERN Document Server

    Poenaru, D N; Greiner, W; Gherghescu, R A; Hamilton, J H; Ramayya, A V

    2002-01-01

    Ternary fission yield for different kinds of light particle accompanied fission processes is compared to the Q-values for the corresponding cold phenomena, showing a striking correlation. The experimental evidence for the existence of a quasimolecular state in sup 1 sup 0 Be accompanied fission of sup 2 sup 5 sup 2 Cf may be explained using a three-center phenomenological model which generates a third minimum in the deformation energy at a separation distance very close to the touching point. This model is a natural extension of the unified approach to three groups of binary decay modes (cold fission, cluster radioactivities and alpha decay), illustrated by sup 2 sup 3 sup 4 U decay modes, and the alpha valley on the potential energy surfaces of sup 1 sup 0 sup 6 Te. New measurements of cluster decay modes, confirming earlier predictions within analytical superasymmetric fission model, are included in a comprehensive half-life systematics. (authors)

  4. Semiconductor nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Marstein Erik Stensrud

    2003-07-01

    This thesis presents a study of two material systems containing semiconductor nanocrystals, namely porous silicon (PSi) films and germanium (Ge) nanocrystals embedded in silicon dioxide (SiO2) films. The PSi films were made by anodic etching of silicon (Si) substrates in an electrolyte containing hydrofluoric acid. The PSi films were doped with erbium (Er) using two different doping methods. electrochemical doping and doping by immersing the PSi films in a solution containing Er. The resulting Er concentration profiles were investigated using scanning electron microscopy (SEN1) combined with energy dispersive X-ray analysis (EDS). The main subject of the work on PSi presented in this thesis was investigating and comparing these two doping methods. Ge nanocrystals were made by implanting Ge ions into Si02 films that were subsequently annealed. However. nanocrystal formation occurred only for certain sets of processing parameters. The dependence of the microstructure of the Ge implanted Si02 films on the processing parameters were therefore investigated. A range of methods were employed for these investigations, including transmission electron microscopy (TEM) combined with EDS, X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectroscopy (SIMS). The observed structures, ranging from Ge nanocrystals to voids with diameters of several tens of nanometers and Ge rich Si02 films without any nanocrystals is described. A model explaining the void formation is also presented. For certain sets of processing parameters. An accumulation of Ge at the Si-Si02 interface was observed. The effect of this accumulation on the electrical properties of MOS structures made from Ge implanted SiO2 films was investigated using CV-measurements. (Author)

  5. Fundamentals of semiconductor devices

    CERN Document Server

    Lindmayer, Joseph

    1965-01-01

    Semiconductor properties ; semiconductor junctions or diodes ; transistor fundamentals ; inhomogeneous impurity distributions, drift or graded-base transistors ; high-frequency properties of transistors ; band structure of semiconductors ; high current densities and mechanisms of carrier transport ; transistor transient response and recombination processes ; surfaces, field-effect transistors, and composite junctions ; additional semiconductor characteristics ; additional semiconductor devices and microcircuits ; more metal, insulator, and semiconductor combinations for devices ; four-pole parameters and configuration rotation ; four-poles of combined networks and devices ; equivalent circuits ; the error function and its properties ; Fermi-Dirac statistics ; useful physical constants.

  6. Effects of pyrite and sphalerite on population compositions, dynamics and copper extraction efficiency in chalcopyrite bioleaching process.

    Science.gov (United States)

    Xiao, Yunhua; Liu, Xueduan; Dong, Weiling; Liang, Yili; Niu, Jiaojiao; Gu, Yabing; Ma, Liyuan; Hao, Xiaodong; Zhang, Xian; Xu, Zhen; Yin, Huaqun

    2017-07-01

    This study used an artificial microbial community with four known moderately thermophilic acidophiles (three bacteria including Acidithiobacillus caldus S1, Sulfobacillus thermosulfidooxidans ST and Leptospirillum ferriphilum YSK, and one archaea, Ferroplasma thermophilum L1) to explore the variation of microbial community structure, composition, dynamics and function (e.g., copper extraction efficiency) in chalcopyrite bioleaching (C) systems with additions of pyrite (CP) or sphalerite (CS). The community compositions and dynamics in the solution and on the ore surface were investigated by real-time quantitative PCR (qPCR). The results showed that the addition of pyrite or sphalerite changed the microbial community composition and dynamics dramatically during the chalcopyrite bioleaching process. For example, A. caldus (above 60%) was the dominant species at the initial stage in three groups, and at the middle stage, still dominated C group (above 70%), but it was replaced by L. ferriphilum (above 60%) in CP and CS groups; at the final stage, L. ferriphilum dominated C group, while F. thermophilum dominated CP group on the ore surface. Furthermore, the additions of pyrite or sphalerite both made the increase of redox potential (ORP) and the concentrations of Fe 3+ and H + , which would affect the microbial community compositions and copper extraction efficiency. Additionally, pyrite could enhance copper extraction efficiency (e.g., improving around 13.2% on day 6) during chalcopyrite bioleaching; on the contrary, sphalerite restrained it.

  7. Low-cost fabrication of ternary CuInSe2 nanocrystals by colloidal route using a novel combination of volatile and non-volatile capping agents

    Science.gov (United States)

    Chawla, Parul; Narain Sharma, Shailesh; Singh, Son

    2014-11-01

    Wet-route synthesis of CuInSe2 (CISe) nanocrystals has been envisaged with the utilization of the unique combination of coordinating ligand and non coordinating solvent. Our work demonstrates the formation of a single-phase, nearly stoichiometric and monodispersive, stable and well-passivated colloidal ternary CISe nanocrystals (band gap (Eg)~1.16 eV) using a novel combination of ligands; viz. volatile arylamine aniline and non-volatile solvent 1-octadecene. The synthesis and growth conditions have been manoeuvred using the colligative properties of the mixture and thus higher growth temperature (~250 °C) could be attained that promoted larger grain growth. The beneficial influence of the capping agents (aniline and 1-octadecene) on the properties of chalcopyrite nanocrystals has enabled us to pictorally model the structural, morphological and optoelectronic aspects of CISe nanoparticles.

  8. Ternary networks reliability and Monte Carlo

    CERN Document Server

    Gertsbakh, Ilya; Vaisman, Radislav

    2014-01-01

    Ternary means “based on three”. This book deals with reliability investigations of  networks whose components subject to failures can be in three states –up, down and middle (mid), contrary to traditionally considered networks  having only binary (up/down) components. Extending binary case to ternary allows to consider more realistic and flexible models for communication, flow and supply networks.

  9. Compound semiconductor alloys: From atomic-scale structure to bandgap bowing

    Science.gov (United States)

    Schnohr, C. S.

    2015-09-01

    Compound semiconductor alloys such as InxGa1-xAs, GaAsxP1-x, or CuInxGa1-xSe2 are increasingly employed in numerous electronic, optoelectronic, and photonic devices due to the possibility of tuning their properties over a wide parameter range simply by adjusting the alloy composition. Interestingly, the material properties are also determined by the atomic-scale structure of the alloys on the subnanometer scale. These local atomic arrangements exhibit a striking deviation from the average crystallographic structure featuring different element-specific bond lengths, pronounced bond angle relaxation and severe atomic displacements. The latter, in particular, have a strong influence on the bandgap energy and give rise to a significant contribution to the experimentally observed bandgap bowing. This article therefore reviews experimental and theoretical studies of the atomic-scale structure of III-V and II-VI zincblende alloys and I-III-VI2 chalcopyrite alloys and explains the characteristic findings in terms of bond length and bond angle relaxation. Different approaches to describe and predict the bandgap bowing are presented and the correlation with local structural parameters is discussed in detail. The article further highlights both similarities and differences between the cubic zincblende alloys and the more complex chalcopyrite alloys and demonstrates that similar effects can also be expected for other tetrahedrally coordinated semiconductors of the adamantine structural family.

  10. Utilizing Energy Transfer in Binary and Ternary Bulk Heterojunction Organic Solar Cells.

    Science.gov (United States)

    Feron, Krishna; Cave, James M; Thameel, Mahir N; O'Sullivan, Connor; Kroon, Renee; Andersson, Mats R; Zhou, Xiaojing; Fell, Christopher J; Belcher, Warwick J; Walker, Alison B; Dastoor, Paul C

    2016-08-17

    Energy transfer has been identified as an important process in ternary organic solar cells. Here, we develop kinetic Monte Carlo (KMC) models to assess the impact of energy transfer in ternary and binary bulk heterojunction systems. We used fluorescence and absorption spectroscopy to determine the energy disorder and Förster radii for poly(3-hexylthiophene-2,5-diyl), [6,6]-phenyl-C61-butyric acid methyl ester, 4-bis[4-(N,N-diisobutylamino)-2,6-dihydroxyphenyl]squaraine (DIBSq), and poly(2,5-thiophene-alt-4,9-bis(2-hexyldecyl)-4,9-dihydrodithieno[3,2-c:3',2'-h][1,5]naphthyridine-5,10-dione). Heterogeneous energy transfer is found to be crucial in the exciton dissociation process of both binary and ternary organic semiconductor systems. Circumstances favoring energy transfer across interfaces allow relaxation of the electronic energy level requirements, meaning that a cascade structure is not required for efficient ternary organic solar cells. We explain how energy transfer can be exploited to eliminate additional energy losses in ternary bulk heterojunction solar cells, thus increasing their open-circuit voltage without loss in short-circuit current. In particular, we show that it is important that the DIBSq is located at the electron donor-acceptor interface; otherwise charge carriers will be trapped in the DIBSq domain or excitons in the DIBSq domains will not be able to dissociate efficiently at an interface. KMC modeling shows that only small amounts of DIBSq (energy transfer.

  11. Dissolution characteristics of sericite in chalcopyrite bioleaching and its effect on copper extraction

    Science.gov (United States)

    Dong, Ying-bo; Li, Hao; Lin, Hai; Zhang, Yuan

    2017-04-01

    The effects of sericite particle size, rotation speed, and leaching temperature on sericite dissolution and copper extraction in a chalcopyrite bioleaching system were examined. Finer particles, appropriate temperature and rotation speed for Acidithiobacillus ferrooxidans resulted in a higher Al3+ dissolution concentration. The Al3+ dissolution concentration reached its highest concentration of 38.66 mg/L after 48-d leaching when the sericite particle size, temperature, and rotation speed were -43 μm, 30°C, and 160 r/min, respectively. Meanwhile, the sericite particle size, rotation speed, and temperature can affect copper extraction. The copper extraction rate is higher when the sericite particle size is finer. An appropriately high temperature is favorable for copper leaching. The dissolution of sericite fitted the shrinking core model, 1-(2/3) α-(1- α)2/3 = k 1 t, which indicates that internal diffusion is the decision step controlling the overall reaction rate in the leaching process. Scanning electron microscopy analysis showed small precipitates covered on the surface of sericite after leaching, which increased the diffusion resistance of the leaching solution and dissolved ions.

  12. An optimized In–CuGa metallic precursors for chalcopyrite thin films

    Energy Technology Data Exchange (ETDEWEB)

    Han, Jun-feng, E-mail: junfeng.han@cnrs-imn.fr [Institut des Matériaux Jean Rouxel (IMN), Université de Nantes, UMR CNRS 6502, 2 rue de la Houssinière, BP 32229, 44322 Nantes Cedex 3 (France); Department of Physics, Peking University, Beijing 100871 (China); Liao, Cheng [Department of Physics, Peking University, Beijing 100871 (China); Chengdu Green Energy and Green Manufacturing Technology R and D Center, Chengdu, Sichuan Province 601207 (China); Jiang, Tao; Xie, Hua-mu; Zhao, Kui [Department of Physics, Peking University, Beijing 100871 (China); Besland, M.-P. [Institut des Matériaux Jean Rouxel (IMN), Université de Nantes, UMR CNRS 6502, 2 rue de la Houssinière, BP 32229, 44322 Nantes Cedex 3 (France)

    2013-10-31

    We report a study of CuGa–In metallic precursors for chalcopyrite thin film. CuGa and In thin films were prepared by DC sputtering at room temperature. Due to low melting point of indium, the sputtering power on indium target was optimized. Then, CuGa and In multilayers were annealed at low temperature. At 120 °C, the annealing treatment could enhance diffusion and alloying of CuGa and In layers; however, at 160 °C, it caused a cohesion and crystalline of indium from the alloy which consequently formed irregular nodules on the film surface. The precursors were selenized to form copper indium gallium selenide (CIGS) thin films. The morphological and structural properties were investigated by scanning electron microscopy, X-ray diffraction and Raman spectra. The relationships between metallic precursors and CIGS films were discussed in the paper. A smooth precursor layer was the key factor to obtain a homogeneous and compact CIGS film. - Highlights: • An optimized sputtered indium film • An optimized alloying process of metallic precursor • An observation of nodules forming on the indium film and precursor surface • An observation of cauliflower structure in copper indium gallium selenide film • The relationship between precursor and CIGS film surface morphology.

  13. Copper solvent extraction from chalcopyrite concentrate acid leach solutions by LIX 984

    Directory of Open Access Journals (Sweden)

    Elamari K.

    2006-01-01

    Full Text Available Copper production from ores or sulphide concentrates is classically realized by pyrometallurgical route. In this study, hydrometallurgical treatment of a copper sulphide concentrate, provided by Hajar Mine (ONA-Group, Morocco, was tested by using a mixture of nitric and hexafluorosilicic acids. Copper is present in the solid product as chalcopyrite and its amount is 28.1 % by weight. Leaching stage allows to dissolve more than 90% of copper witch is accompanied, in the same averages, by Zn and Fe. The leach solution obtained has pH = 0.6 and Eh = 580 mV/ENH and contains 19.3 g/L Cu, 18.1 g/L Fe, 4.5 g/L Zn and 0.03 g/L Pb. The recovery of copper from this leach solution was curried out by solvent extraction using Lix 984, diluted in Escaid 110. McCabe - Thiele distribution isotherms showed that at pH 1.7 total and selective copper extraction can be realized with Øo:Øa =1.5:1 in 3 extraction stages. Stripping of the loaded copper by treating the organic phases was easily obtained by a sulphuric acid solution.

  14. Structural, electronic, linear, and nonlinear optical properties of ZnCdTe{sub 2} chalcopyrite

    Energy Technology Data Exchange (ETDEWEB)

    Ouahrani, Tarik [Laboratoire de Physique Theorique, Universite de Tlemcen, B.P. 230, Tlemcen 13000 (Algeria); Reshak, Ali H. [Institute of Physical Biology, South Bohemia University, Nove Hrady 37333 (Czech Republic); School of Microelectronic Engineering, University of Malaysia Perlis (UniMAP), Block A, Kompleks Pusat Pengajian, 02600 Arau Jejawi, Perlis (Malaysia); Khenata, R. [Laboratoire de Physique Quantique et de Modelisation Mathematique, Universite de Mascara, Mascara 29000 (Algeria); Department of Physics and Astronomy, Faculty of Science, King Saud University, P.O. Box 2455, Riyadh 11451 (Saudi Arabia); Baltache, H.; Amrani, B. [Laboratoire de Physique Quantique et de Modelisation Mathematique, Universite de Mascara, Mascara 29000 (Algeria); Bouhemadou, A. [Department of Physics and Astronomy, Faculty of Science, King Saud University, P.O. Box 2455, Riyadh 11451 (Saudi Arabia); Faculty of Sciences, Department of Physics, University of Setif, Setif 19000 (Algeria)

    2011-03-15

    We report results of first-principles density functional calculations using the full-potential linearized augmented plane wave method. The generalized gradient approximation (GGA) and the Engel-Vosko-GGA (EV-GGA) formalism were used for the exchange-correlation energy to calculate the structural, electronic, linear, and nonlinear optical properties of the chalcopyrite ZnCdTe{sub 2} compound. The valence band maximum and the conduction band minimum are located at the {gamma}-point, resulting in a direct band gap of about 0.71 eV for GGA and 1.29 eV for EV-GGA. The results of bulk properties, such as lattice parameters (a, c, and u), bulk modulus B, and its pressure derivative B' are evaluated. The optical properties of this compound, namely the real and the imaginary parts of the dielectric function, reflectivity, and refractive index, show a considerable anisotropy as a consequence ZnCdTe{sub 2} posseses a strong birefringence. In addition, the extinction coefficient, the electron energy loss function, and the nonlinear susceptibility are calculated and their spectra are analyzed. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. Special quasirandom structures for binary/ternary group IV random alloys

    KAUST Repository

    Chroneos, Alexander I.

    2010-06-01

    Simulation of defect interactions in binary/ternary group IV semiconductor alloys at the density functional theory level is difficult due to the random distribution of the constituent atoms. The special quasirandom structures approach is a computationally efficient way to describe the random nature. We systematically study the efficacy of the methodology and generate a number of special quasirandom cells for future use. In order to demonstrate the applicability of the technique, the electronic structures of E centers in Si1-xGex and Si1-x -yGexSny alloys are discussed for a range of nearest neighbor environments. © 2010 Elsevier B.V. All rights reserved.

  16. Defects in semiconductor nanostructures

    Indian Academy of Sciences (India)

    Impurities play a pivotal role in semiconductors. One part in a million of phosphorous in silicon alters the conductivity of the latter by several orders of magnitude. Indeed, the information age is possible only because of the unique role of shallow impurities in semiconductors. Although work in semiconductor nanostructures ...

  17. Solid spectroscopy: semiconductors

    International Nuclear Information System (INIS)

    Silva, C.E.T.G. da

    1983-01-01

    Photoemission as technique of study of the semiconductor electronic structure is shortly discussed. Homogeneous and heterogeneous semiconductors, where volume and surface electronic structure, core levels and O and H chemisorption in GaAs, Schottky barrier are treated, respectively. Amorphous semiconductors are also discussed. (L.C.) [pt

  18. Chalcopyrite CuInSe2 films prepared by reactive sputtering

    International Nuclear Information System (INIS)

    Lommasson, T.C.; Burnett, A.F.; Chou, L.H.; Thornton, J.A.; Kim, M.

    1987-01-01

    Polycrystalline films of CuInSe 2 have been prepared on glass substrates by reactive cosputtering from Cu and In planar magnetron targets using Ar-H 2 Se as a working gas. The film compositions were close to the Cu 2 Se-In 2 Se 3 tie-line of the ternary phase diagram with Cu/In ratios ranging from 0.75 to about 2. This paper reports on measurements of the structural, electronic and optical properties of the films. The coatings on the Cu-rich side of the stoichiometric composition were characterized by a columnar structure with an uneven surface topography

  19. Semiconductors with structurally determined vacancies PAC studies

    CERN Document Server

    Dietrich, M; Kortus, J; Unterricker, S; Deicher, M; Burchard, A; Magerle, R

    1999-01-01

    Ternary semiconductors of type Square Operator A/sup II/B/sub 2//sup III/C/sub 4//sup VI/ with an ordered array of vacancies were investigated by PAC. Thereby the six probes /sup 111m/Cd, /sup 117/Cd (/sup 117/In), /sup 111/In(/sup 111/Cd), /sup 111/Ag(/sup 111/Cd), /sup 77/Br(/sup 77/Se) and /sup 77/Kr(/sup 77/Br) were applied. The positions of the different probes are determined and the corresponding electric field gradients by the WIEN 95 code calculated. By /sup 111/Ag(/sup 111/Cd)-probes the vacancies could be substituted. The electronic charge density distributions are discussed. At elevated temperatures the substances show order- disorder transitions. As compared to the X-ray diffraction patterns the beginning of disorder is observed by PAC at distinctly lower temperatures. (7 refs).

  20. The ternary system nickel-boron-silicon

    International Nuclear Information System (INIS)

    Lugscheider, E.; Reimann, H.; Knotek, O.

    1975-01-01

    The ternary system Nickel-Boron-Silicon was established at 850 0 C by means of X-ray diffraction, metallographic and micro-hardness examinations. The well known binary nickel borides and silicides resp. were confirmed. In the boron-silicon system two binary phases, SiBsub(4-x) with x approximately 0.7 and SiB 6 were found the latter in equilibrium with the β-rhombohedral boron. Confirming the two ternary silicon borides a greater homogeneity range was found for Ni 6 Si 2 B, the phase Nisub(4,6)Si 2 B published by Uraz and Rundqvist can better be described by the formula Nisub(4.29)Si 2 Bsub(1.43). In relation to further investigations we measured melting temperatures in ternary Ni-10 B-Si alloys by differential thermoanalysis. (author)

  1. True ternary fission of 252Cf

    International Nuclear Information System (INIS)

    Vijayaraghavan, K.R.; Balasubramaniam, M.; Oertzen, W. von

    2014-01-01

    Splitting of heavy radioactive nucleus into three fragments is known as ternary fission. If the size of the fragments are almost equal it is referred to as true ternary fission. Recently, Yu. V. Pyatkov et al observed/reported the experimental observation of true ternary fission in 252 Cf. In this work, the possibilities of different true ternary fission modes of 252 Cf through potential energy surface (PES) calculations based on three cluster model (TCM) are discussed. In TCM a condition on the mass numbers of the fission fragments is implied as A 1 ≥ A 2 ≥ A 3 in order to avoid repetition of combinations. Due to this condition, the values of Z 3 vary from 0 to 36 and Z 2 vary from 16 to 51. Of the different pairs having similar (Z 2 , Z 3 ) with different potential energy, a pair possessing minimum potential energy is chosen. Thus identified favourable combinations are plotted. For the PES calculations the arrangement of the fragments is considered in the order of A 1 +A 2 +A 3 . i.e. the heavy and the lightest fragments are kept at the ends. It is seen that the deepest minimum in the PES occurs for Z 3 =2 labelled as (Z 2 ; 2) indicating He accompanied breakup as the most favourable one. Of which, the breakup with Z 2 around 46 to 48 is the least (shown by dashed (Z 1 = 50) and dotted (Z 1 = 52) lines indicating a constant Z 1 value). The other notable minima in the PES are labelled and they correspond to the (Z 2 , Z 3 ) pairs viz., (20, 20), (28, 20), (28, 28) and (32, 32). Of these four minima, the first three are associated with the magic numbers 20 and 28. For Z 3 =20, there are two minimums at (20,20) and (28,20) among them (28,20) is the lowest minimum through which the minimum-path passes, and it is the ternary decay observed by Yu. V. Pyatkov et al. The fourth minima is the most interesting due to the fact that it corresponds to true ternary fission mode with Z 2 =32, Z 3 =32 and Z 1 =34. The minimum potential energy path also goes through this true

  2. A Josephson ternary associative memory cell

    International Nuclear Information System (INIS)

    Morisue, M.; Suzuki, K.

    1989-01-01

    This paper describes a three-valued content addressable memory cell using a Josephson complementary ternary logic circuit named as JCTL. The memory cell proposed here can perform three operations of searching, writing and reading in ternary logic system. The principle of the memory circuit is illustrated in detail by using the threshold-characteristics of the JCTL. In order to investigate how a high performance operation can be achieved, computer simulations have been made. Simulation results show that the cycle time of memory operation is 120psec, power consumption is about 0.5 μW/cell and tolerances of writing and reading operation are +-15% and +-24%, respectively

  3. Semiconductor Physical Electronics

    CERN Document Server

    Li, Sheng

    2006-01-01

    Semiconductor Physical Electronics, Second Edition, provides comprehensive coverage of fundamental semiconductor physics that is essential to an understanding of the physical and operational principles of a wide variety of semiconductor electronic and optoelectronic devices. This text presents a unified and balanced treatment of the physics, characterization, and applications of semiconductor materials and devices for physicists and material scientists who need further exposure to semiconductor and photonic devices, and for device engineers who need additional background on the underlying physical principles. This updated and revised second edition reflects advances in semicondutor technologies over the past decade, including many new semiconductor devices that have emerged and entered into the marketplace. It is suitable for graduate students in electrical engineering, materials science, physics, and chemical engineering, and as a general reference for processing and device engineers working in the semicondi...

  4. Semiconductor Modeling Techniques

    CERN Document Server

    Xavier, Marie

    2012-01-01

    This book describes the key theoretical techniques for semiconductor research to quantitatively calculate and simulate the properties. It presents particular techniques to study novel semiconductor materials, such as 2D heterostructures, quantum wires, quantum dots and nitrogen containing III-V alloys. The book is aimed primarily at newcomers working in the field of semiconductor physics to give guidance in theory and experiment. The theoretical techniques for electronic and optoelectronic devices are explained in detail.

  5. Contacts to semiconductors

    International Nuclear Information System (INIS)

    Tove, P.A.

    1975-08-01

    Contacts to semiconductors play an important role in most semiconductor devices. These devices range from microelectronics to power components, from high-sensitivity light or radiation detectors to light-emitting of microwave-generating components. Silicon is the dominating material but compound semiconductors are increasing in importance. The following survey is an attempt to classify contact properties and the physical mechanisms involved, as well as fabrication methods and methods of investigation. The main interest is in metal-semiconductor type contacts where a few basic concepts are dealt with in some detail. (Auth.)

  6. Semiconductor Electrical Measurements Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The Semiconductor Electrical Measurements Laboratory is a research laboratory which complements the Optical Measurements Laboratory. The laboratory provides for Hall...

  7. Growth Mechanism of Nanowires: Binary and Ternary Chalcogenides

    Science.gov (United States)

    Singh, N. B.; Coriell, S. R.; Su, Ching-Hua; Hopkins, R. H.; Arnold, B.; Choa, Fow-Sen; Cullum, Brian

    2016-01-01

    Semiconductor nanowires exhibit very exciting optical and electrical properties including high transparency and a several order of magnitude better photocurrent than thin film and bulk materials. We present here the mechanism of nanowire growth from the melt-liquid-vapor medium. We describe preliminary results of binary and ternary selenide materials in light of recent theories. Experiments were performed with lead selenide and thallium arsenic selenide systems which are multifunctional material and have been used for detectors, acousto-optical, nonlinear and radiation detection applications. We observed that small units of nanocubes and elongated nanoparticles arrange and rearrange at moderate melt undercooling to form the building block of a nanowire. Since we avoided the catalyst, we observed self-nucleation and uncontrolled growth of wires from different places. Growth of lead selenide nanowires was performed by physical vapor transport method and thallium arsenic selenide nanowire by vapor-liquid-solid (VLS) method. In some cases very long wires (>mm) are formed. To achieve this goal experiments were performed to create situation where nanowires grew on the surface of solid thallium arsenic selenide itself.

  8. Delay Insensitive Ternary CMOS Logic for Secure Hardware

    Directory of Open Access Journals (Sweden)

    Ravi S. P. Nair

    2015-09-01

    Full Text Available As digital circuit design continues to evolve due to progress of semiconductor processes well into the sub 100 nm range, clocked architectures face limitations in a number of cases where clockless asynchronous architectures generate less noise and produce less electro-magnetic interference (EMI. This paper develops the Delay-Insensitive Ternary Logic (DITL asynchronous design paradigm that combines design aspects of similar dual-rail asynchronous paradigms and Boolean logic to create a single wire per bit, three voltage signaling and logic scheme. DITL is compared with other delay insensitive paradigms, such as Pre-Charge Half-Buffers (PCHB and NULL Convention Logic (NCL on which it is based. An application of DITL is discussed in designing secure digital circuits resistant to side channel attacks based on measurement of timing, power, and EMI signatures. A Secure DITL Adder circuit is designed at the transistor level, and several variance parameters are measured to validate the efficiency of DITL in resisting side channel attacks. The DITL design methodology is then applied to design a secure 8051 ALU.

  9. Ion Beam Nanostructuring of HgCdTe Ternary Compound

    Science.gov (United States)

    Smirnov, Aleksey B.; Savkina, Rada K.; Udovytska, Ruslana S.; Gudymenko, Oleksandr I.; Kladko, Vasyl P.; Korchovyi, Andrii A.

    2017-05-01

    Systematic study of mercury cadmium telluride thin films subjected to the ion beam bombardment was carried out. The evolution of surface morphology of (111) Hg1 - x Cd x Te ( x 0.223) epilayers due to 100 keV B+ and Ag+ ion irradiation was studied by AFM and SEM methods. X-ray photoelectron spectroscopy and X-ray diffraction methods were used for the investigation of the chemical compound and structural properties of the surface and subsurface region. It was found that in the range of nanoscale, arrays of holes and mounds on Hg0.777Cd0.223Te (111) surface as well as the polycrystalline Hg1 - x Cd x Te cubic phase with alternative compound ( x 0.20) have been fabricated using 100 keV ion beam irradiation of the basic material. Charge transport investigation with non-stationary impedance spectroscopy method has shown that boron-implanted structures are characterized by capacity-type impedance whereas for silver-implanted structures, an inductive-type impedance (or "negative capacitance") is observed. A hybrid system, which integrates the nanostructured ternary compound (HgCdTe) with metal-oxide (Ag2O) inclusions, was fabricated by Ag+ ion bombardment. The sensitivity of such metal-oxide-semiconductor hybrid structure for sub-THz radiation was detected with NEP 4.5 × 10-8 W/Hz1/2at ν ≈ 140 GHz and 296 K without amplification.

  10. Indacenodithienothiophene-Based Ternary Organic Solar Cells

    International Nuclear Information System (INIS)

    Gasparini, Nicola; García-Rodríguez, Amaranda; Prosa, Mario; Bayseç, Şebnem; Palma-Cando, Alex; Katsouras, Athanasios; Avgeropoulos, Apostolos; Pagona, Georgia; Gregoriou, Vasilis G.; Chochos, Christos L.; Allard, Sybille; Scherf, Ulrich; Brabec, Christoph J.; Ameri, Tayebeh

    2017-01-01

    One of the key aspects to achieve high efficiency in ternary bulk-hetorojunction solar cells is the physical and chemical compatibility between the donor materials. Here, we report the synthesis of a novel conjugated polymer (P1) containing alternating pyridyl[2,1,3]thiadiazole between two different donor fragments, dithienosilole and indacenodithienothiophene (IDTT), used as a sensitizer in a host system of indacenodithieno[3,2-b]thiophene,2,3-bis(3-(octyloxy)phenyl)quinoxaline (PIDTTQ) and [6,6]-phenyl C 70 butyric acid methyl ester (PC 71 BM). We found that the use of the same IDTT unit in the host and guest materials does not lead to significant changes in the morphology of the ternary blend compared to the host binary. With the complementary use of optoelectronic characterizations, we found that the ternary cells suffer from a lower mobility-lifetime (μτ) product, adversely impacting the fill factor. However, the significant light harvesting in the near infrared region improvement, compensating the transport losses, results in an overall power conversion efficiency enhancement of ~7% for ternary blends as compared to the PIDTTQ:PC 71 BM devices.

  11. Angular distribution in ternary cold fission

    International Nuclear Information System (INIS)

    Delion, D.S.; J.W. Goethe Univ., Frankfurt; Sandulescu, A.; J.W. Goethe Univ., Frankfurt; Greiner, W.

    2003-01-01

    We describe the spontaneous ternary cold fission of 252 Cf, accompanied by 4 He, 10 Be and 14 C. The light cluster decays from the first resonant eigenstate in the Coulomb potential plus a harmonic oscillator potential. We have shown that the angular distribution of the emitted light particle is strongly connected with its deformation and the equatorial distance. (author)

  12. Superconducting state parameters of ternary metallic glasses

    Indian Academy of Sciences (India)

    Quadratic T C equations have been proposed and found successful. Also, the present findings are found to be in qualitative agreement with other such earlier reported data, which confirms the superconducting phase in the ternary superconductors. The pseudo-alloy-atom (PAA) model was applied for the first time instead of ...

  13. The use of ternary mixtures in concrete.

    Science.gov (United States)

    2014-05-01

    This manual is a summary of the findings of a comprehensive study. Its purpose is to provide engineers with the information they need to make educated decisions on the use of ternary mixtures for constructing concrete structures. It discusses the eff...

  14. TERNARY ALLOYS OF URANIUM, COLUMBIUM, AND ZIRCONIUM

    Science.gov (United States)

    Foote, F.G.

    1960-08-01

    Ternary alloys of uranium are described which are useful as neutron- reflecting materials in a fast neutron reactor. They are especially resistant to corrosion caused by oxidative processes of gascous or aqueous origin and comprise uranium as the predominant metal with zirconiunn and niobium wherein the total content of the minor alloying elements is between 2 and 8% by weight.

  15. Superconducting state parameters of ternary metallic glasses

    Indian Academy of Sciences (India)

    Administrator

    to binary metallic glasses. They are of interest since third element can modify the physical properties of binary metallic glasses and can also be used as a probe to study the host. ..... conducting nature in the present case. When we. Figure 6. Variation of transition temperature (TC) with valance (Z) of ternary metallic glasses.

  16. Ternary alloy nanocatalysts for hydrogen evolution reaction

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 39; Issue 2. Ternary alloy nanocatalysts for ... It is to be noted that synthesis of nanocrystallineternary alloys with precise composition is a big challenge which can be overcome by choosing an appropriate microemulsion system. High electrocatalytic activity towards ...

  17. Self-triggered coordination with ternary controllers

    NARCIS (Netherlands)

    De Persis, Claudio; Frasca, Paolo

    2012-01-01

    This paper regards coordination of networked systems with ternary controllers. We develop a hybrid coordination system which implements a self-triggered communication policy, based on polling the neighbors upon need. We prove that the proposed scheme ensures finite-time convergence to a neighborhood

  18. A High-Yield Synthesis of Chalcopyrite CuInS2 Nanoparticles with Exceptional Size Control

    Directory of Open Access Journals (Sweden)

    Chivin Sun

    2009-01-01

    Full Text Available We report high-yield and efficient size-controlled syntheses of Chalcopyrite CuInS2 nanoparticles by decomposing molecular single source precursors (SSPs via microwave irradiation in the presence of 1,2-ethanedithiol at reaction temperatures as low as 100°C and times as short as 30 minutes. The nanoparticles sizes were 1.8 nm to 10.8 nm as reaction temperatures were varied from 100°C to 200°C with the bandgaps from 2.71 eV to 1.28 eV with good size control and high yields (64%–95%. The resulting nanoparticles were analyzed by XRD, UV-Vis, ICP-OES, XPS, SEM, EDS, and HRTEM. Titration studies by 1H NMR using SSP 1 with 1,2-ethanedithiol and benzyl mercaptan were conducted to elucidate the formation of Chalcopyrite CuInS2 nanoparticles.

  19. A comparative study of solution-processed low- and high-band-gap chalcopyrite thin-film solar cells

    International Nuclear Information System (INIS)

    Park, Se Jin; Moon, Sung Hwan; Min, Byoung Koun; Cho, Yunae; Kim, Ji Eun; Kim, Dong-Wook; Lee, Doh-Kwon; Gwak, Jihye; Kim, Jihyun

    2014-01-01

    Low-cost and printable chalcopyrite thin-film solar cells were fabricated by a precursor solution-based coating method with a multi-step heat-treatment process (oxidation, sulfurization, and selenization). The high-band-gap (1.57 eV) Cu(In x Ga 1−x )S 2 (CIGS) solar cell showed a high open-circuit voltage of 787 mV, whereas the low-band-gap (1.12 eV) Cu(In x Ga 1−x )(S 1−y Se y ) 2 (CIGSSe) cell exhibited a high short-circuit current density of 32.6 mA cm −2 . The energy conversion efficiencies were 8.28% for CIGS and 8.81% for CIGSSe under standard irradiation conditions. Despite similar efficiencies, the two samples showed notable differences in grain size, surface morphology, and interfacial properties. Low-temperature transport and admittance characteristics of the samples clearly revealed how their structural differences influenced their photovoltaic and electrical properties. Such analyses provide insight into the enhanced solar cell performance of the solution-processed chalcopyrite thin films. (paper)

  20. Design of a novel quantum reversible ternary up-counter

    Science.gov (United States)

    Houshmand, Pouran; Haghparast, Majid

    2015-08-01

    Reversible logic has been recently considered as an interesting and important issue in designing combinational and sequential circuits. The combination of reversible logic and multi-valued logic can improve power dissipation, time and space utilization rate of designed circuits. Only few works have been reported about sequential reversible circuits and almost there are no paper exhibited about quantum ternary reversible counter. In this paper, first we designed 2-qutrit and 3-qutrit quantum reversible ternary up-counters using quantum ternary reversible T-flip-flop and quantum reversible ternary gates. Then we proposed generalized quantum reversible ternary n-qutrit up-counter. We also introduced a new approach for designing any type of n-qutrit ternary and reversible counter. According to the results, we can conclude that applying second approach quantum reversible ternary up-counter is better than the others.

  1. A Solution-Doped Polymer Semiconductor:Insulator Blend for Thermoelectrics.

    Science.gov (United States)

    Kiefer, David; Yu, Liyang; Fransson, Erik; Gómez, Andrés; Primetzhofer, Daniel; Amassian, Aram; Campoy-Quiles, Mariano; Müller, Christian

    2017-01-01

    Poly(ethylene oxide) is demonstrated to be a suitable matrix polymer for the solution-doped conjugated polymer poly(3-hexylthiophene). The polarity of the insulator combined with carefully chosen processing conditions permits the fabrication of tens of micrometer-thick films that feature a fine distribution of the F4TCNQ dopant:semiconductor complex. Changes in electrical conductivity from 0.1 to 0.3 S cm -1 and Seebeck coefficient from 100 to 60 μV K -1 upon addition of the insulator correlate with an increase in doping efficiency from 20% to 40% for heavily doped ternary blends. An invariant bulk thermal conductivity of about 0.3 W m -1 K -1 gives rise to a thermoelectric Figure of merit ZT ∼ 10 -4 that remains unaltered for an insulator content of more than 60 wt%. Free-standing, mechanically robust tapes illustrate the versatility of the developed dopant:semiconductor:insulator ternary blends.

  2. A Solution-Doped Polymer Semiconductor:Insulator Blend for Thermoelectrics

    KAUST Repository

    Kiefer, David

    2016-09-01

    Poly(ethylene oxide) is demonstrated to be a suitable matrix polymer for the solution-doped conjugated polymer poly(3-hexylthiophene). The polarity of the insulator combined with carefully chosen processing conditions permits the fabrication of tens of micrometer-thick films that feature a fine distribution of the F4TCNQ dopant:semiconductor complex. Changes in electrical conductivity from 0.1 to 0.3 S cm−1 and Seebeck coefficient from 100 to 60 μV K−1 upon addition of the insulator correlate with an increase in doping efficiency from 20% to 40% for heavily doped ternary blends. An invariant bulk thermal conductivity of about 0.3 W m−1 K−1 gives rise to a thermoelectric Figure of merit ZT ∼ 10−4 that remains unaltered for an insulator content of more than 60 wt%. Free-standing, mechanically robust tapes illustrate the versatility of the developed dopant:semiconductor:insulator ternary blends.

  3. Semiconductor Research Experimental Techniques

    CERN Document Server

    Balkan, Naci

    2012-01-01

    The book describes the fundamentals, latest developments and use of key experimental techniques for semiconductor research. It explains the application potential of various analytical methods and discusses the opportunities to apply particular analytical techniques to study novel semiconductor compounds, such as dilute nitride alloys. The emphasis is on the technique rather than on the particular system studied.

  4. Terahertz semiconductor nonlinear optics

    DEFF Research Database (Denmark)

    Turchinovich, Dmitry; Hvam, Jørn Märcher; Hoffmann, Matthias

    2013-01-01

    In this proceedings we describe our recent results on semiconductor nonlinear optics, investigated using single-cycle THz pulses. We demonstrate the nonlinear absorption and self-phase modulation of strong-field THz pulses in doped semiconductors, using n-GaAs as a model system. The THz nonlinear...

  5. Semiconductors data handbook

    CERN Document Server

    Madelung, Otfried

    2004-01-01

    This volume Semiconductors: Data Handbook contains frequently used data from the corresponding larger Landolt-Börnstein handbooks in a low price book for the individual scientist working in the laboratory. The Handbook contain important information about a large number of semiconductors

  6. Semiconductor radiation detection systems

    CERN Document Server

    2010-01-01

    Covers research in semiconductor detector and integrated circuit design in the context of medical imaging using ionizing radiation. This book explores other applications of semiconductor radiation detection systems in security applications such as luggage scanning, dirty bomb detection and border control.

  7. Room Temperature Hard Radiation Detectors Based on Solid State Compound Semiconductors: An Overview

    Science.gov (United States)

    Mirzaei, Ali; Huh, Jeung-Soo; Kim, Sang Sub; Kim, Hyoun Woo

    2018-03-01

    Si and Ge single crystals are the most common semiconductor radiation detectors. However, they need to work at cryogenic temperatures to decrease their noise levels. In contrast, compound semiconductors can be operated at room temperature due to their ability to grow compound materials with tunable densities, band gaps and atomic numbers. Highly efficient room temperature hard radiation detectors can be utilized in biomedical diagnostics, nuclear safety and homeland security applications. In this review, we discuss room temperature compound semiconductors. Since the field of radiation detection is broad and a discussion of all compound materials for radiation sensing is impossible, we discuss the most important materials for the detection of hard radiation with a focus on binary heavy metal semiconductors and ternary and quaternary chalcogenide compounds.

  8. Disorder phenomena in covalent semiconductors

    International Nuclear Information System (INIS)

    Popescu, M.A.

    1975-01-01

    The structure of the amorphous semiconductors has been investigated by means of X-ray diffraction and by computer simulation of random network models. Amorphous germanium contains mainly five and six-membered rings of atoms. In glassy state, the ternary compounds A 2 B 4 C 2 5 , such as CdGeAs 2 contain only even rings of atoms (six-membered and eight-membered rings). In the memory glasses of the type A 2 B 4 C 2 5 , such as GeAs 2 Te 7 , the valency state of every element is that from the crystal and important van der Waals forces are effective in the network. No Ge-Ge, Ge-As and As-As bonds are formed. The high pressure forms of the germanium have been simulated by computer. The force constants of the covalent bonds in Ge III and Ge IV differ from those in Ge I. The bond bending force constant decreases rapidly when the density of the crystal increases, a fact which has been imparted to a reduction of the sp 3 hybridization. The compressibility curve of the Ge I has been explained. The effect of the radial and uniaxial deformation on the non-crystalline networks has been studied. The compressibility of the amorphous germanium is by 1.5 per cent greater than that of crystalline germanium. The Poisson coefficient for a-Ge network is 0.233. The structure of the As 2 S 3 glass doped with different amounts of germanium (up to 40 at. per cent) and silver (up to 12 at. per cent) has been investigated. The As 2 S 3 Gesub(x) compositions are constituted from a disordered packing of structural units whose chemical composition and relative proportion in the glass essentially depends on the germanium content. (author)

  9. Compound Semiconductor Radiation Detectors

    CERN Document Server

    Owens, Alan

    2012-01-01

    Although elemental semiconductors such as silicon and germanium are standard for energy dispersive spectroscopy in the laboratory, their use for an increasing range of applications is becoming marginalized by their physical limitations, namely the need for ancillary cooling, their modest stopping powers, and radiation intolerance. Compound semiconductors, on the other hand, encompass such a wide range of physical and electronic properties that they have become viable competitors in a number of applications. Compound Semiconductor Radiation Detectors is a consolidated source of information on all aspects of the use of compound semiconductors for radiation detection and measurement. Serious Competitors to Germanium and Silicon Radiation Detectors Wide-gap compound semiconductors offer the ability to operate in a range of hostile thermal and radiation environments while still maintaining sub-keV spectral resolution at X-ray wavelengths. Narrow-gap materials offer the potential of exceeding the spectral resolutio...

  10. Organic semiconductor crystals.

    Science.gov (United States)

    Wang, Chengliang; Dong, Huanli; Jiang, Lang; Hu, Wenping

    2018-01-22

    Organic semiconductors have attracted a lot of attention since the discovery of highly doped conductive polymers, due to the potential application in field-effect transistors (OFETs), light-emitting diodes (OLEDs) and photovoltaic cells (OPVs). Single crystals of organic semiconductors are particularly intriguing because they are free of grain boundaries and have long-range periodic order as well as minimal traps and defects. Hence, organic semiconductor crystals provide a powerful tool for revealing the intrinsic properties, examining the structure-property relationships, demonstrating the important factors for high performance devices and uncovering fundamental physics in organic semiconductors. This review provides a comprehensive overview of the molecular packing, morphology and charge transport features of organic semiconductor crystals, the control of crystallization for achieving high quality crystals and the device physics in the three main applications. We hope that this comprehensive summary can give a clear picture of the state-of-art status and guide future work in this area.

  11. Controlling the emission wavelength in group III-V semiconductor laser diodes

    KAUST Repository

    Ooi, Boon S.

    2016-12-29

    Methods are provided for modifying the emission wavelength of a semiconductor quantum well laser diode, e.g. by blue shifting the emission wavelength. The methods can be applied to a variety of semiconductor quantum well laser diodes, e.g. group III-V semiconductor quantum wells. The group III-V semiconductor can include AlSb, AlAs, Aln, AlP, BN, GaSb, GaAs, GaN, GaP, InSb, InAs, InN, and InP, and group III-V ternary semiconductors alloys such as AlxGai.xAs. The methods can results in a blue shifting of about 20 meV to 350 meV, which can be used for example to make group III-V semiconductor quantum well laser diodes with an emission that is orange or yellow. Methods of making semiconductor quantum well laser diodes and semiconductor quantum well laser diodes made therefrom are also provided.

  12. Insights into the selective adsorption mechanism of a novel flotation reagent 4-Amino-5-mercapto-1,2,4-triazole on chalcopyrite surface: an experimental and computational study.

    Science.gov (United States)

    Yin, Zhigang; Hu, Yuehua; Sun, Wei; Zhang, Chenyang; He, Jianyong; Xu, Zhijie; Zou, Jingxiang; Guan, Changping; Zhang, Chen Hu; Guan, Qingjun; Lin, Shangyong

    2018-02-28

    In the present study, a novel compound 4-Amino-5-mercapto-1,2,4-triazole was first synthesized and its selective adsorption mechanism on the surface of chalcopyrite was comprehensively investigated using UV-vis spectra, Zeta potential, Fourier Transform Infrared Spectroscopy(FTIR), X-ray Photoelectron Spectroscopy Measurements(XPS), and Time of Flight Secondary Ion Mass Spectrometry (ToF-SIMS) and first principle calculations. The experimental and computational results consistently demonstrated that AMT would chemisorb onto the chalcopyrite surface by the formation of a five-membered chelate ring. The first principle periodic calculations further indicated that AMT would prefer to adsorb onto Cu rather than Fe due to the more negative adsorption energy of AMT on Cu in the chalcopyrite (001) surface, which was further confirmed by the coordination bonding energies of AMT-Cu and AMT-Fe based on the simplified cluster models at a higher accuracy level (UB3LYP/Def2-TZVP). The bench scale results indicated that the selective index improved significantly when using AMT as a chalcopyrite depressant in Cu-Mo flotation separation.

  13. Metal-Semiconductor Contacts

    Science.gov (United States)

    Pugh, D. I.

    Metal-semiconductor contacts display a range of electrical characteristics from strongly rectifying to ohmic, each having its own applications. The rectifying properties of metal points on metallic sulphides were used extensively as detectors in early radio experiments, while during the second world war the rectifying point contact diode became important as a frequency detector and low level microwave radar detector [1]. Since 1945 the development of metal semiconductor contacts has been stimulated by the intense activity in the field of semiconductor physics and has remained vital in the ohmic connection of semiconductor devices with the outside world. The developments in surface science and the increased use of Schottky barriers in microelectronics has lead to much research with the aim of obtaining a full understanding of the physics of barrier formation and of current transport across the metal-semiconductor interface. Large gain spin electronic devices are possible with appropriate designs by incorporating ferromagnetic layers with semiconductors such as silicon [2]. This inevitably leads to metal-semiconductor contacts, and the impact of such junctions on the device must be considered. In this section we aim to look simply at the physical models that can be used to understand the electrical properties that can arise from these contacts, and then briefly discuss how deviations of these models can occur in practical junctions.

  14. Low-cost fabrication of ternary CuInSe{sub 2} nanocrystals by colloidal route using a novel combination of volatile and non-volatile capping agents

    Energy Technology Data Exchange (ETDEWEB)

    Chawla, Parul; Narain Sharma, Shailesh, E-mail: shailesh@nplindia.org; Singh, Son

    2014-11-15

    Wet-route synthesis of CuInSe{sub 2} (CISe) nanocrystals has been envisaged with the utilization of the unique combination of coordinating ligand and non coordinating solvent. Our work demonstrates the formation of a single-phase, nearly stoichiometric and monodispersive, stable and well-passivated colloidal ternary CISe nanocrystals (band gap (E{sub g})∼1.16 eV) using a novel combination of ligands; viz. volatile arylamine aniline and non-volatile solvent 1-octadecene. The synthesis and growth conditions have been manoeuvred using the colligative properties of the mixture and thus higher growth temperature (∼250 °C) could be attained that promoted larger grain growth. The beneficial influence of the capping agents (aniline and 1-octadecene) on the properties of chalcopyrite nanocrystals has enabled us to pictorally model the structural, morphological and optoelectronic aspects of CISe nanoparticles. - Graphical abstract: Without resorting to any post-selenization process and using the colligative properties of the mixture comprising of volatile aniline and non-volatile 1-octadecene to manoeuvre the growth conditions to promote Ostwald ripening, a single phase, monodispersive and nearly stoichiometric ternary CISe nanocrystals are formed by wet-synthesis route. - Highlights: • Wet-route synthesis of CISe nanocrystals reported without post-selenization process. • Single-phase, stable and well-passivated colloidal ternary CISe nanocrystals formed. • Novel combination of capping agents: volatile aniline and non-volatile 1-octadecene. • Higher growth temperature attained using the colligative properties of the mixture. • Metallic salts presence explains exp. and theoretical boiling point difference.

  15. Coherent dynamics in semiconductors

    DEFF Research Database (Denmark)

    Hvam, Jørn Märcher

    1998-01-01

    Ultrafast nonlinear optical spectroscopy is used to study the coherent dynamics of optically excited electron-hole pairs in semiconductors. Coulomb interaction implies that the optical inter-band transitions are dominated, at least at low temperatures, by excitonic effects. They are further...... and molecular systems are found and studied in the exciton-biexciton system of semiconductors. At densities where strong exciton interactions, or many-body effects, become dominant, the semiconductor Bloch equations present a more rigorous treatment of the phenomena Ultrafast degenerate four-wave mixing is used...

  16. Physics of semiconductor lasers

    CERN Document Server

    Mroziewicz, B; Nakwaski, W

    2013-01-01

    Written for readers who have some background in solid state physics but do not necessarily possess any knowledge of semiconductor lasers, this book provides a comprehensive and concise account of fundamental semiconductor laser physics, technology and properties. The principles of operation of these lasers are therefore discussed in detail with the interrelations between their design and optical, electrical and thermal properties. The relative merits of a large number of laser structures and their parameters are described to acquaint the reader with the various aspects of the semiconductor l

  17. Semiconductors bonds and bands

    CERN Document Server

    Ferry, David K

    2013-01-01

    As we settle into this second decade of the twenty-first century, it is evident that the advances in micro-electronics have truly revolutionized our day-to-day lifestyle. The technology is built upon semiconductors, materials in which the band gap has been engineered for special values suitable to the particular application. This book, written specifically for a one semester course for graduate students, provides a thorough understanding of the key solid state physics of semiconductors. It describes how quantum mechanics gives semiconductors unique properties that enabled the micro-electronics revolution, and sustain the ever-growing importance of this revolution.

  18. Spin physics in semiconductors

    CERN Document Server

    2017-01-01

    This book offers an extensive introduction to the extremely rich and intriguing field of spin-related phenomena in semiconductors. In this second edition, all chapters have been updated to include the latest experimental and theoretical research. Furthermore, it covers the entire field: bulk semiconductors, two-dimensional semiconductor structures, quantum dots, optical and electric effects, spin-related effects, electron-nuclei spin interactions, Spin Hall effect, spin torques, etc. Thanks to its self-contained style, the book is ideally suited for graduate students and researchers new to the field.

  19. Defects in semiconductors

    CERN Document Server

    Romano, Lucia; Jagadish, Chennupati

    2015-01-01

    This volume, number 91 in the Semiconductor and Semimetals series, focuses on defects in semiconductors. Defects in semiconductors help to explain several phenomena, from diffusion to getter, and to draw theories on materials' behavior in response to electrical or mechanical fields. The volume includes chapters focusing specifically on electron and proton irradiation of silicon, point defects in zinc oxide and gallium nitride, ion implantation defects and shallow junctions in silicon and germanium, and much more. It will help support students and scientists in their experimental and theoret

  20. Superconducting state parameters of ternary metallic glasses

    Indian Academy of Sciences (India)

    Administrator

    When used with a suitable form of dialectic screening functions, this potential has also been found to yield good results in computing the SSP of (Ni33Zr67)1–x ..... superconducting nature. Hence, (Ni33Zr67)1–xMx. (M = Ti, V, Co, Cu) ternary metallic glasses exhibit super- conducting nature in the present case. When we.

  1. Equilibrium study for ternary mixtures of biodiesel

    Science.gov (United States)

    Doungsri, S.; Sookkumnerd, T.; Wongkoblap, A.; Nuchitprasittichai, A.

    2017-11-01

    The liquid-liquid equilibrium (LLE) data for the ternary mixtures of methanol + fatty acid methyl ester (FAME) + palm oil and FAME + palm oil + glycerol at various temperatures from 35 to 55°C, the tie lines and binodial curves were also investigated and plotted in the equilibrium curve. The experimental results showed that the binodial curves of methanol + FAME + palm oil depended significantly with temperature while the binodial curves of FAME + palm oil + glycerol illustrated insignificant change with temperatures. The interaction parameters between liquid pair obtained for NRTL (Nonrandom Two-Liquid) and UNIQUAC (Universal Quasi-Chemical Theory) models from the experimental data were also investigated. It was found that the correlated parameters of UNIQUAC model for system of FAME + palm oil + glycerol, denoted as a13 and a31, were 580.42K and -123.69K, respectively, while those for system of methanol + FAME + palm oil, denoted as a42 and a24, were 71.48 K and 965.57K, respectively. The ternary LLE data reported here would be beneficial for engineers and scientists to use for prediction of yield and purity of biodiesel for the production. The UNIQUAC model agreed well with the experimental data of ternary mixtures of biodiesel.

  2. Design of ternary clocked adiabatic static random access memory

    Science.gov (United States)

    Pengjun, Wang; Fengna, Mei

    2011-10-01

    Based on multi-valued logic, adiabatic circuits and the structure of ternary static random access memory (SRAM), a design scheme of a novel ternary clocked adiabatic SRAM is presented. The scheme adopts bootstrapped NMOS transistors, and an address decoder, a storage cell and a sense amplifier are charged and discharged in the adiabatic way, so the charges stored in the large switch capacitance of word lines, bit lines and the address decoder can be effectively restored to achieve energy recovery during reading and writing of ternary signals. The PSPICE simulation results indicate that the ternary clocked adiabatic SRAM has a correct logic function and low power consumption. Compared with ternary conventional SRAM, the average power consumption of the ternary adiabatic SRAM saves up to 68% in the same conditions.

  3. Biggest semiconductor installed

    CERN Multimedia

    2008-01-01

    Scientists and technicians at the European Laboratory for Particle Physics, commonly known by its French acronym CERN (Centre Europen pour la Recherche Nuclaire), have completed the installation of the largest semiconductor silicon detector.

  4. Isotopically controlled semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Haller, E.E.

    2004-11-15

    A review of recent research involving isotopically controlled semiconductors is presented. Studies with isotopically enriched semiconductor structures experienced a dramatic expansion at the end of the Cold War when significant quantities of enriched isotopes of elements forming semiconductors became available for worldwide collaborations. Isotopes of an element differ in nuclear mass, may have different nuclear spins and undergo different nuclear reactions. Among the latter, the capture of thermal neutrons which can lead to neutron transmutation doping, can be considered the most important one for semiconductors. Experimental and theoretical research exploiting the differences in all the properties has been conducted and will be illustrated with selected examples. Manuel Cardona, the longtime editor-in-chief of Solid State Communications has been and continues to be one of the major contributors to this field of solid state physics and it is a great pleasure to dedicate this review to him.

  5. Semiconductor nuclear detectors

    International Nuclear Information System (INIS)

    Schaub, Bernard

    1976-01-01

    Three semiconductors are nowadays available for nuclear detection (germanium, mercury iodide, cadmium telluride). Their methods of elaboration are briefly described and, as a conclusion, a very close at-hand development of cadmium telluride is foreseen [fr

  6. Compact semiconductor lasers

    CERN Document Server

    Yu, Siyuan; Lourtioz, Jean-Michel

    2014-01-01

    This book brings together in a single volume a unique contribution by the top experts around the world in the field of compact semiconductor lasers to provide a comprehensive description and analysis of the current status as well as future directions in the field of micro- and nano-scale semiconductor lasers. It is organized according to the various forms of micro- or nano-laser cavity configurations with each chapter discussing key technical issues, including semiconductor carrier recombination processes and optical gain dynamics, photonic confinement behavior and output coupling mechanisms, carrier transport considerations relevant to the injection process, and emission mode control. Required reading for those working in and researching the area of semiconductors lasers and micro-electronics.

  7. Characteristics of chemical bond and vacancy formation in chalcopyrite-type CuInSe2 and related compounds

    International Nuclear Information System (INIS)

    Maeda, Tsuyoshi; Wada, Takahiro

    2009-01-01

    We studied characteristics of chemical bond and vacancy formation in chalcopyrite-type CuInSe 2 (CIS) by first principles calculations. The chalcopyrite-type CIS has two kinds of chemical bonds, Cu-Se and In-Se. The Cu-Se bond is a weak covalent bonding because electrons occupy both bonding and antibonding orbitals of Cu 3d and Se 4p and occupy only the bonding orbital (a 1 ) of Cu 4s and Se 4p and do not occupy the antibonding orbital (a 1 * ) of Cu 4s and Se 4p. On the other hand, the In-Se bond has a partially covalent and partially ionic character because the In 5s orbital covalently interacts with Se 4p; the In 5p orbital is higher than Se 4p and so the electron in the In 5p orbital moves to the Se 4p orbital. The average bond order of the Cu-Se and In-Se bonds can be calculated to be 1/4 and 1, respectively. The bond order of Cu-Se is smaller than that of In-Se. The characteristics of these two chemical bonds are related to the formation of Cu and In vacancies in CIS. The formation energy of the Cu vacancy is smaller than that of the In vacancy under both Cu-poor and In-poor conditions. The displacement (Δl) of the surrounding Se atoms after the formation of the Cu vacancy is smaller than the Δl after the formation of the In vacancy. The interesting and unique characteristics of CIS are discussed on the basis of the characteristics of the chemical bond. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  8. Geochemistry of pyrite and chalcopyrite from an active black smoker in 49.6°E Southwest Indian Ridge

    Science.gov (United States)

    Yuan, Bo; Yang, Yaomin; Yu, Hongjun; Zhao, Yuexia; Ding, Qingfeng; Yang, Jichao; Tang, Xin

    2017-06-01

    Active hydrothermal chimneys, as the product of submarine hydrothermal activity, can be used to determine the fluid evolution and formation process of potential volcanic-hosted massive sulfide deposits. A hard-won specimen from an active hydrothermal chimney was collected in the 49.6°E ultraslow-spreading Southwest Indian Ridge (SWIR) field through a television-guided grab. A geochemical study of prominent sulfide (e.g., pyrite and chalcopyrite) included in this sample was performed using laser ablation inductively coupled plasma mass spectroscopy. The early sulfides produced at low temperature are of disseminated fine-grained anhedral morphology, whereas the late ones with massive, coarse euhedral features precipitated in a high-temperature setting. The systematic variations in the contents of minor and trace elements are apparently related to the crystallization sequence, as well as to texture. Micro-disseminated anhedral sulfides rich in Pb, As, Ni, Ba, Mn, Mo, U, and V were formed during the initial chimney wall growth, whereas those rich in Sn, Se, and Co with massive, coarse euhedral morphology were formed within the late metallogenic stage. The hydrothermal fluid composition has experienced a great change during the chimney growth. Such a conclusion is consistent with that indicated by using principal component analysis, which is a powerful statistical analysis method widely used to project multidimensional datasets (e.g., element contents in different mineral phases) into a few directions. This distribution pattern points to crystallographic controls on minor and trace element uptake during chimney growth, occurring with concomitant variations in the fluid composition evolutionary history. In this pyrite-chalcopyrite-bearing active hydrothermal chimney at the SWIR, the metal concentration and precipitation of sulfides largely occurred at the seafloor as a result of mixing between the upwelling hot hydrothermal fluid and cold seawater. Over the course of

  9. Structural and elastic properties of defect chalcopyrite HgGa{sub 2}S{sub 4} under high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Gomis, O., E-mail: osgohi@fis.upv.es [Centro de Tecnologías Físicas: Acústica, Materiales y Astrofísica, MALTA Consolider Team, Universitat Politècnica de València, 46022 València (Spain); Santamaría-Pérez, D. [Departamento de Física Aplicada-ICMUV, MALTA Consolider Team, Universitat de València, Edificio de Investigación, C/Dr. Moliner 50, Burjassot, 46100 València (Spain); Departamento de Química Física I, Universidad Complutense de Madrid, MALTA Consolider Team, Avenida Complutense s/n, 28040 Madrid (Spain); Vilaplana, R.; Luna, R. [Centro de Tecnologías Físicas: Acústica, Materiales y Astrofísica, MALTA Consolider Team, Universitat Politècnica de València, 46022 València (Spain); Sans, J.A.; Manjón, F.J. [Instituto de Diseño para la Fabricación y Producción Automatizada, MALTA Consolider Team, Universitat Politècnica de València, 46022 València (Spain); Errandonea, D. [Departamento de Física Aplicada-ICMUV, MALTA Consolider Team, Universitat de València, Edificio de Investigación, C/Dr. Moliner 50, Burjassot, 46100 València (Spain); and others

    2014-01-15

    Highlights: • Single crystals of HgGa{sub 2}S{sub 4} with defect-chalcopyrite (DC) structure were synthesized. • High-pressure X-ray diffraction in DC-HgGa{sub 2}S{sub 4} was performed. • Equation of state of DC-HgGa{sub 2}S{sub 4} determined (bulk modulus of 48.4 GPa). • Calculated elastic constants of DC-HgGa{sub 2}S{sub 4} reported at different pressures. • DC-HgGa{sub 2}S{sub 4} becomes mechanically unstable above 13.8 GPa. -- Abstract: In this work, we focus on the study of the structural and elastic properties of mercury digallium sulfide (HgGa{sub 2}S{sub 4}) at high pressures. This compound belongs to the family of AB{sub 2}X{sub 4} ordered-vacancy compounds and exhibits a tetragonal defect chalcopyrite structure. X-ray diffraction measurements at room temperature have been performed under compression up to 15.1 GPa in a diamond anvil cell. Our measurements have been complemented and compared with ab initio total energy calculations. The axial compressibility and the equation of state of the low-pressure phase of HgGa{sub 2}S{sub 4} have been experimentally and theoretically determined and compared to other related ordered-vacancy compounds. The pressure dependence of the theoretical cation–anion and vacancy-anion distances and compressibilities in HgGa{sub 2}S{sub 4} are reported and discussed in comparison to other related ordered-vacancy compounds. Finally, the pressure dependence of the theoretical elastic constants and elastic moduli of HgGa{sub 2}S{sub 4} has been studied. Our calculations indicate that the low-pressure phase of HgGa{sub 2}S{sub 4} becomes mechanically unstable above 13.8 GPa.

  10. Radiation effects in semiconductors

    CERN Document Server

    2011-01-01

    There is a need to understand and combat potential radiation damage problems in semiconductor devices and circuits. Written by international experts, this book explains the effects of radiation on semiconductor devices, radiation detectors, and electronic devices and components. These contributors explore emerging applications, detector technologies, circuit design techniques, new materials, and innovative system approaches. The text focuses on how the technology is being used rather than the mathematical foundations behind it. It covers CMOS radiation-tolerant circuit implementations, CMOS pr

  11. Market survey of semiconductors

    International Nuclear Information System (INIS)

    Mackintosh, I.M.; Diegel, D.; Brown, A.; Brinker, C.S. den

    1977-06-01

    Examination of technology and product trends over the range of current and future products in integrated circuits and optoelectronic displays. Analysis and forecast of major economic influences that affect the production costs of integrated circuits and optoelectronic displays. Forecast of the applications and markets for integrated circuits up to 1985 in West Europe, the USA and Japan. Historic development of the semiconductor industry and the prevailing tendencies - factors which influence success in the semiconductor industry. (orig.) [de

  12. Ternary q-Virasoro-Witt Hom-Nambu-Lie algebras

    International Nuclear Information System (INIS)

    Ammar, F; Makhlouf, A; Silvestrov, S

    2010-01-01

    In this paper we construct ternary q-Virasoro-Witt algebras which q-deform the ternary Virasoro-Witt algebras constructed by Curtright, Fairlie and Zachos using su(1, 1) enveloping algebra techniques. The ternary Virasoro-Witt algebras constructed by Curtright, Fairlie and Zachos depend on a parameter and are not Nambu-Lie algebras for all but finitely many values of this parameter. For the parameter values for which the ternary Virasoro-Witt algebras are Nambu-Lie, the corresponding ternary q-Virasoro-Witt algebras constructed in this paper are also Hom-Nambu-Lie because they are obtained from the ternary Nambu-Lie algebras using the composition method. For other parameter values this composition method does not yield a Hom-Nambu-Lie algebra structure for q-Virasoro-Witt algebras. We show however, using a different construction, that the ternary Virasoro-Witt algebras of Curtright, Fairlie and Zachos, as well as the general ternary q-Virasoro-Witt algebras we construct, carry a structure of the ternary Hom-Nambu-Lie algebra for all values of the involved parameters.

  13. Description of light charged particle emission in ternary fission

    International Nuclear Information System (INIS)

    Andreev, A. V.; Adamian, G. G.; Antonenko, N. V.; Kuklin, S. N.; Scheid, W.

    2010-01-01

    We consider the motion of three fragments starting from the scission point of ternary system. In the alpha-accompanied ternary fission the initial conditions are not the free parameters and determined by minimization of potential energy at scission point. In the trajectory calculations the angular distribution and mean value of the kinetic energy of the alpha-particles are well described in the spontaneous ternary fission of 252 Cf. In the Be- and C-accompanied ternary fission we found that the emission of the third particle occurs from one of the heavy fragments after their separation. (authors)

  14. Ternary q-Virasoro-Witt Hom-Nambu-Lie algebras

    Energy Technology Data Exchange (ETDEWEB)

    Ammar, F [Faculte des Sciences, Universite de Sfax, BP 1171, 3000 Sfax (Tunisia); Makhlouf, A [Laboratoire de Mathematiques, Informatique et Applications, Universite de Haute Alsace, 4, rue des Freres Lumiere F-68093 Mulhouse (France); Silvestrov, S, E-mail: Faouzi.Ammar@rnn.fss.t, E-mail: Abdenacer.Makhlouf@uha.f, E-mail: sergei.silvestrov@math.lth.s [Centre for Mathematical Sciences, Lund University, Box 118, SE-221 00 Lund (Sweden)

    2010-07-02

    In this paper we construct ternary q-Virasoro-Witt algebras which q-deform the ternary Virasoro-Witt algebras constructed by Curtright, Fairlie and Zachos using su(1, 1) enveloping algebra techniques. The ternary Virasoro-Witt algebras constructed by Curtright, Fairlie and Zachos depend on a parameter and are not Nambu-Lie algebras for all but finitely many values of this parameter. For the parameter values for which the ternary Virasoro-Witt algebras are Nambu-Lie, the corresponding ternary q-Virasoro-Witt algebras constructed in this paper are also Hom-Nambu-Lie because they are obtained from the ternary Nambu-Lie algebras using the composition method. For other parameter values this composition method does not yield a Hom-Nambu-Lie algebra structure for q-Virasoro-Witt algebras. We show however, using a different construction, that the ternary Virasoro-Witt algebras of Curtright, Fairlie and Zachos, as well as the general ternary q-Virasoro-Witt algebras we construct, carry a structure of the ternary Hom-Nambu-Lie algebra for all values of the involved parameters.

  15. Research and development of photovoltaic power system. Optimization of bandgap of chalcopyrite semiconductors; Taiyoko hatsuden system no kenkyu kaihatsu. Kinseitaihaba no saitekika no kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Konagai, M. [Tokyo Institute of Technology, Tokyo (Japan). Faculty of Engineering

    1994-12-01

    This paper reports the result obtained during fiscal 1994 on research on research on optimization of bandgap in thin film compound solar cells. In research on Cu(InGa)Se2 thin film solar cells by using a gas phase selenide making process, discussions were given on optimizing the following three processes: a process to raise temperature of a precursor film formed at a substrate temperature of about 150{degree}C, a selenide making process to perform annealing at about 500{degree}C, and a temperature reducing process. Good characteristics were obtained when selenium amount in the precursor is about 50%. In a bandgap control viewpoint, it was found that the conversion efficiency decreases rapidly when Ga composition is higher than 50%. A conversion efficiency of 14.9% was obtained to date at the Ga/(In+Ga) ratio of 0.4. In research on Cu(InGa)Se2 thin film solar cells by using a simultaneous deposition method, a conversion efficiency of 13.5% was obtained at a bandgap width of about 1.3 eV during research on manufacturing ZnO/CdS/Cu(InGa)Se2 thin film solar cells by using the simultaneous deposition method. Research has been carried out on manufacturing Cu(InGa)Se2 thin film solar cells using ZnSe interface layers. 8 figs.

  16. Synthesis and Characterization of Novel Ternary and Quaternary Alkali Metal Thiophosphates

    KAUST Repository

    Alahmary, Fatimah S.

    2014-05-01

    The ongoing development of nonlinear optical (NLO) crystals such as coherent mid-IR sources focuses on various classes of materials such as ternary and quaternary metal chalcophosphates. In case of thiophosphates, the connection between PS4-tetrahedral building blocks and metals gives rise to a broad structural variety where approximately one third of all known ternary (A/P/S) and quaternary (A/M/P/S) (A = alkali metal, M = metal) structures are acentric and potential nonlinear optical materials. The molten alkali metal polychalcophosphate fluxes are a well-established method for the synthesis of new ternary and quaternary thiophosphate and selenophosphate compounds. It has been a wide field of study and investigation through the last two decades. Here, the flux method is used for the synthesis of new quaternary phases containing Rb, Ag, P and S. Four new alkali metal thiophosphates, Rb4P2S10, RbAg5(PS4), Rb2AgPS4 and Rb3Ag9(PS4)4, have been synthesized successfully from high purity elements and binary starting materials. The new compounds were characterized by single crystal and powder X-ray diffraction, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), ultraviolet-visible (UV-VIS), Raman spectroscopy, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). These compounds show interesting structural variety and physical properties. The crystal structures feature 3D anionic framework built up of PS4 tetrahedral units and charge balanced by Ag and alkali metal cations. All prepared compounds are semiconductors with band gap between 2.3 eV to 2.6 eV and most of them are thermally stable up to 600ºC.

  17. Neutron Damage and MAX Phase Ternary Compounds

    International Nuclear Information System (INIS)

    Barsoum, Michael; Hoffman, Elizabeth; Sindelar, Robert; Garcua-Diaz, Brenda; Kohse, Gordon

    2014-01-01

    The Demands of Gen IV nuclear power plants for long service life under neutron radiation at high temperature are severe. Advanced materials that would withstand high temperatures (up to 1000+ C) to high doses in a neutron field would be ideal for reactor internal structures and would add to the long service life and reliability of the reactors. The objective of this work is to investigate the response of a new class of machinable, conductive, layered, ternary transition metal carbides and nitrides - the so-called MAX phases - to low and moderate neutron dose levels.

  18. Dumbbells and onions in ternary nucleation.

    Science.gov (United States)

    Nellas, Ricky B; Chen, Bin; Siepmann, J Ilja

    2007-06-14

    Molecular simulations for a ternary nucleation system (water/n-nonane/1-butanol) demonstrate a more complex nucleation mechanism than previously thought, where critical nuclei with different compositions are present even for a given vapour-phase composition; the spatial distribution in these critical nuclei is heterogeneous and dumbbell and onion motifs are found; in the former, water and nonane nano-droplets are connected through a butanol handle, while in the latter a water core is surrounded by a nonane corona with an interfacial butanol shell.

  19. Neutron Damage and MAX Phase Ternary Compounds

    Energy Technology Data Exchange (ETDEWEB)

    Barsoum, Michael [Drexel Univ., Philadelphia, PA (United States); Hoffman, Elizabeth [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Sindelar, Robert [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Garcua-Duaz, Brenda [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Kohse, Gordon [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

    2014-06-17

    The Demands of Gen IV nuclear power plants for long service life under neutron radiation at high temperature are severe. Advanced materials that would withstand high temperatures (up to 1000+ C) to high doses in a neutron field would be ideal for reactor internal structures and would add to the long service life and reliability of the reactors. The objective of this work is to investigate the response of a new class of machinable, conductive, layered, ternary transition metal carbides and nitrides - the so-called MAX phases - to low and moderate neutron dose levels.

  20. Viscometric and thermodynamic studies of interactions in ternary ...

    Indian Academy of Sciences (India)

    Viscometric and thermodynamic studies of interactions in ternary solutions containing sucrose and aqueous alkali metal halides at 293.15, 303.15 and 313.15 K. Reena Gupta Mukhtar Singh ... Keywords. Ternary solutions; interactions of ionic and nonionic solutes; partial molar volumes; sucrosealkali metal halide solutions.

  1. A study of phase separation in ternary alloys

    Indian Academy of Sciences (India)

    Unknown

    Department of Metallurgy, Indian Institute of Science, Bangalore 560 012, India. Abstract. We have studied the evolution of microstructure when a disordered ternary alloy is quenched into a ternary miscibility gap. We have used computer simulations based on multicomponent Cahn–Hilliard (CH) equations for cA and cB, the ...

  2. A high-speed interconnect network using ternary logic

    DEFF Research Database (Denmark)

    Madsen, Jens Kargaard; Long, S. I.

    1995-01-01

    This paper describes the design and implementation of a high-speed interconnect network (ICN) for a multiprocessor system using ternary logic. By using ternary logic and a fast point-to-point communication technique called STARI (Self-Timed At Receiver's Input), the communication between...

  3. Thermodynamic modeling of the Ti-Al-Cr ternary system

    International Nuclear Information System (INIS)

    Chen Leyi; Qiu Aitao; Liu Lanjie; Jiang Ming; Lu Xionggang; Li Chonghe

    2011-01-01

    Research highlights: → The full experimental results of the Ti-Al-Cr ternary system and its sub-binary systems are reviewed and analysed in detail. → Based on the latest thermodynamic assessments of the Ti-Al, Ti-Cr and Al-Cr systems and the ternary experimental data in literature, the thermodynamic parameters of the Ti-Al-Cr ternary system are fully assessed by the Calphad method. → The transformation of disorder to order (bcc a 2 to B2) and the new ternary compound L 12T i 25 Cr 8 Al 67 are considered in this work. - Abstract: The Ti-Al-Cr ternary system is one of the most important systems to studying the titanium alloys. Some experimental data of this ternary system are available and a few partial thermodynamic assessments are reported. However, no full thermodynamic descriptions were published. In this study, the previous work on the Ti-Al-Cr system and its related binary systems are reviewed. Based on the thermodynamic descriptions of the Ti-Al, Ti-Cr and Al-Cr systems and the ternary experimental data in literature, the Ti-Al-Cr ternary system is assessed by means of the Calphad method. Several isothermal sections from 1073 K to 1573 K and some invariant reactions are calculated, which are in good agreement with the most of the experimental results.

  4. Density-Driven segregation in Binary and Ternary Granular Systems

    NARCIS (Netherlands)

    Windows-Yule, Kit; Parker, David

    2015-01-01

    We present a first experimental study of density-induced segregation within a three-dimensional, vibrofluidised, ternary granular system. Using Positron Emission Particle Tracking (PEPT), we study the steady-state particle distributions achieved by binary and ternary granular beds under a variety of

  5. Calculation of ternary interdiffusion coefficients using a single diffusion couple

    Czech Academy of Sciences Publication Activity Database

    Čermák, Jiří; Rothová, Věra

    2016-01-01

    Roč. 54, č. 5 (2016), s. 305-314 ISSN 0023-432X R&D Projects: GA MŠk(CZ) ED1.1.00/02.0068 Institutional support: RVO:68081723 Keywords : diffusion * interdiffusion * ternary alloys * ternary diffusion coefficients Subject RIV: BJ - Thermodynamic s Impact factor: 0.366, year: 2016

  6. Coherent dynamics in semiconductors

    DEFF Research Database (Denmark)

    Hvam, Jørn Märcher

    1998-01-01

    enhanced in quantum confined lower-dimensional systems, where exciton and biexciton effects dominate the spectra even at room temperature. The coherent dynamics of excitons are at modest densities well described by the optical Bloch equations and a number of the dynamical effects known from atomic......Ultrafast nonlinear optical spectroscopy is used to study the coherent dynamics of optically excited electron-hole pairs in semiconductors. Coulomb interaction implies that the optical inter-band transitions are dominated, at least at low temperatures, by excitonic effects. They are further...... and molecular systems are found and studied in the exciton-biexciton system of semiconductors. At densities where strong exciton interactions, or many-body effects, become dominant, the semiconductor Bloch equations present a more rigorous treatment of the phenomena Ultrafast degenerate four-wave mixing is used...

  7. Hydrogen in semiconductors II

    CERN Document Server

    Nickel, Norbert H; Weber, Eicke R; Nickel, Norbert H

    1999-01-01

    Since its inception in 1966, the series of numbered volumes known as Semiconductors and Semimetals has distinguished itself through the careful selection of well-known authors, editors, and contributors. The "Willardson and Beer" Series, as it is widely known, has succeeded in publishing numerous landmark volumes and chapters. Not only did many of these volumes make an impact at the time of their publication, but they continue to be well-cited years after their original release. Recently, Professor Eicke R. Weber of the University of California at Berkeley joined as a co-editor of the series. Professor Weber, a well-known expert in the field of semiconductor materials, will further contribute to continuing the series' tradition of publishing timely, highly relevant, and long-impacting volumes. Some of the recent volumes, such as Hydrogen in Semiconductors, Imperfections in III/V Materials, Epitaxial Microstructures, High-Speed Heterostructure Devices, Oxygen in Silicon, and others promise that this tradition ...

  8. Fundamentals of semiconductor lasers

    CERN Document Server

    Numai, Takahiro

    2015-01-01

    This book explains physics under the operating principles of semiconductor lasers in detail based on the experience of the author, dealing with the first manufacturing of phase-shifted DFB-LDs and recent research on transverse modes.   The book also bridges a wide gap between journal papers and textbooks, requiring only an undergraduate-level knowledge of electromagnetism and quantum mechanics, and helps readers to understand journal papers where definitions of some technical terms vary, depending on the paper. Two definitions of the photon density in the rate equations and two definitions of the phase-shift in the phase-shifted DFB-LD are explained, and differences in the calculated results are indicated, depending on the definitions.    Readers can understand the physics of semiconductor lasers and analytical tools for Fabry-Perot LDs, DFB-LDs, and VCSELs and will be stimulated to develop semiconductor lasers themselves.

  9. Basic Semiconductor Physics

    CERN Document Server

    Hamaguchi, Chihiro

    2010-01-01

    This book presents a detailed description of the basic semiconductor physics. The reader is assumed to have a basic command of mathematics and some elementary knowledge of solid state physics. The text covers a wide range of important phenomena in semiconductors, from the simple to the advanced. The reader can understand three different methods of energy band calculations, empirical pseudo-potential, k.p perturbation and tight-binding methods. The effective mass approximation and electron motion in a periodic potential, Boltzmann transport equation and deformation potentials used for full band Monte Carlo simulation are discussed. Experiments and theoretical analysis of cyclotron resonance are discussed in detail because the results are essential to the understanding of semiconductor physics. Optical and transport properties, magneto-transport, two dimensional electron gas transport (HEMT and MOSFET), and quantum transport are reviewed, explaining optical transition, electron phonon interactions, electron mob...

  10. Rapid thermal processing for production of chalcopyrite thin films for solar cells: Design, analysis, and experimental implementation

    Science.gov (United States)

    Lovelett, Robert J.

    The direct conversion of solar energy to electricity, or photovoltaic energy conversion, has a number of environmental, social, and economic advantages over conventional electricity generation from fossil fuels. Currently, the most commonly-used material for photovoltaics is crystalline silicon, which is now produced at large scale and silicon-based devices have achieved power conversion efficiencies over 25% However, alternative materials, such as inorganic thin films, offer a number of advantages including the potential for lower manufacturing costs, higher theoretical efficiencies, and better performance in the field. One of these materials is the chalcopyrite Cu(InGa)(SeS) 2, which has demonstrated module efficiencies over 17% and cell efficiencies over 22%. Cu(InGa)(SeS)2 is now in the early stages of commercialization using a precursor reaction process referred to as a "selenization/sulfization" reaction. The precursor reaction process is promising because it has demonstrated high efficiency along with the large area (approximately 1 m2) uniformity that is required for modules. However, some challenges remain that limit the growth of the chalcopyrite solar cell industry including: slow reactions that limit process throughput, a limited understanding of complex reaction kinetics and transport phenomena that affect the through-film composition, and the use of highly toxic H2Se in the reaction process. In this work, I approach each of these challenges. First, to improve process throughput, I designed and implemented a rapid thermal processing (RTP) reactor, whereby the samples are heated by a 1000 W quartz-halogen lamp that is capable of fast temperature ramps and high temperature dwells. With the reactor in place, however, achieving effective temperature control in the thin film material system is complicated by two intrinsic process characteristics: (i) the temperature of the Cu(InGa)(SeS)2 film cannot be measured directly, which leaves the system without

  11. Electronic structure of epitaxial chalcopyrite surfaces and interfaces for photovoltaics; Elektronische Struktur epitaktischer Chalkopyrite und deren Heterokontakte fuer die Photovoltaik

    Energy Technology Data Exchange (ETDEWEB)

    Hofmann, Andreas

    2012-02-14

    This thesis constitutes a comprehensive study of the surface physics of epitaxial CuInSe{sub 2} films. It comprises analyses of the surface morphology and reconstruction, electronic band structure as well as hetero-junctions relevant to photovoltaic applications. Therefore, especially the aspect of stoichiometry variation from the CuInSe{sub 2} to the copper-deficient defect phases was considered. Preparation and analysis was completely performed under ultra-high vacuum conditions in order to ensure the investigation of well-defined samples free of contaminants. For some of the analysis techniques, single-crystalline samples are indispensable: They allow for the determination of surface periodicity by low-energy electron diffraction (LEED). In combination with concentration depth profiling by angle-resolved x-ray photoemission, to types of surface reconstructions could be distinguished for the near-stoichiometric CuInSe{sub 2}(112) surface. In the copper-rich case, it is stabilized by Cu{sub In} anti-site defects and on the indium-rich side by 2 V{sub Cu} defects, as predicted by surface total energy calculations by Jaffe and Zunger. Both configurations correspond to a c(4 x 2) reconstruction of the zinc blende type (111) surface. For the defect compound CuIn{sub 3}Se{sub 5}, a sphalerite order of the surface was found, which points at a weakening or absence of the chalcopyrite order in the bulk of the material. The unusual stability of the (112) surface could also be proven by comparison with the reconstruction and surface order of (001) and (220) surfaces. The results from surface analysis were used to measure the valence band structure of the epitaxial samples by synchrotron-based angle-resolved photoelectron spectroscopy. The CuInSe{sub 2}(001) surface gives access to the high symmetry directions {Gamma}-T and {Gamma}-N of momentum space. By contrasting the data obtained for the stoichiometric surface with the copper-poor defect compound, a reduction of the

  12. Semiconductor opto-electronics

    CERN Document Server

    Moss, TS; Ellis, B

    1972-01-01

    Semiconductor Opto-Electronics focuses on opto-electronics, covering the basic physical phenomena and device behavior that arise from the interaction between electromagnetic radiation and electrons in a solid. The first nine chapters of this book are devoted to theoretical topics, discussing the interaction of electromagnetic waves with solids, dispersion theory and absorption processes, magneto-optical effects, and non-linear phenomena. Theories of photo-effects and photo-detectors are treated in detail, including the theories of radiation generation and the behavior of semiconductor lasers a

  13. Advances in semiconductor lasers

    CERN Document Server

    Coleman, James J; Jagadish, Chennupati

    2012-01-01

    Semiconductors and Semimetals has distinguished itself through the careful selection of well-known authors, editors, and contributors. Originally widely known as the ""Willardson and Beer"" Series, it has succeeded in publishing numerous landmark volumes and chapters. The series publishes timely, highly relevant volumes intended for long-term impact and reflecting the truly interdisciplinary nature of the field. The volumes in Semiconductors and Semimetals have been and will continue to be of great interest to physicists, chemists, materials scientists, and device engineers in academia, scien

  14. Introductory semiconductor device physics

    CERN Document Server

    Parker, Greg

    2004-01-01

    ATOMS AND BONDINGThe Periodic TableIonic BondingCovalent BondingMetallic bondingvan der Waals BondingStart a DatabaseENERGY BANDS AND EFFECTIVE MASSSemiconductors, Insulators and MetalsSemiconductorsInsulatorsMetalsThe Concept of Effective MassCARRIER CONCENTRATIONS IN SEMICONDUCTORSDonors and AcceptorsFermi-LevelCarrier Concentration EquationsDonors and Acceptors Both PresentCONDUCTION IN SEMICONDUCTORSCarrier DriftCarrier MobilitySaturated Drift VelocityMobility Variation with TemperatureA Derivation of Ohm's LawDrift Current EquationsSemiconductor Band Diagrams with an Electric Field Presen

  15. Compound semiconductor device physics

    CERN Document Server

    Tiwari, Sandip

    2013-01-01

    This book provides one of the most rigorous treatments of compound semiconductor device physics yet published. A complete understanding of modern devices requires a working knowledge of low-dimensional physics, the use of statistical methods, and the use of one-, two-, and three-dimensional analytical and numerical analysis techniques. With its systematic and detailed**discussion of these topics, this book is ideal for both the researcher and the student. Although the emphasis of this text is on compound semiconductor devices, many of the principles discussed will also be useful to those inter

  16. Optical processes in semiconductors

    CERN Document Server

    Pankove, Jacques I

    1975-01-01

    Based on a series of lectures at Berkeley, 1968-1969, this is the first book to deal comprehensively with all of the phenomena involving light in semiconductors. The author has combined, for the graduate student and researcher, a great variety of source material, journal research, and many years of experimental research, adding new insights published for the first time in this book.Coverage includes energy states in semiconductors and their perturbation by external parameters, absorption, relationships between optical constants, spectroscopy, radiative transitions, nonradiative recombination

  17. Plasmonic spectral tunability of conductive ternary nitrides

    Energy Technology Data Exchange (ETDEWEB)

    Kassavetis, S.; Patsalas, P., E-mail: ppats@physics.auth.gr [Department of Physics, Aristotle University of Thessaloniki, GR-54124 Thessaloniki (Greece); Bellas, D. V.; Lidorikis, E. [Department of Materials Science and Engineering, University of Ioannina, GR-45110 Ioannina (Greece); Abadias, G. [Institut Pprime, Département Physique et Mécanique des Matériaux, Université de Poitiers-CNRS-ENSMA, 86962 Chasseneuil-Futuroscope (France)

    2016-06-27

    Conductive binary transition metal nitrides, such as TiN and ZrN, have emerged as a category of promising alternative plasmonic materials. In this work, we show that ternary transition metal nitrides such as Ti{sub x}Ta{sub 1−x}N, Ti{sub x}Zr{sub 1−x}N, Ti{sub x}Al{sub 1−x}N, and Zr{sub x}Ta{sub 1−x}N share the important plasmonic features with their binary counterparts, while having the additional asset of the exceptional spectral tunability in the entire visible (400–700 nm) and UVA (315–400 nm) spectral ranges depending on their net valence electrons. In particular, we demonstrate that such ternary nitrides can exhibit maximum field enhancement factors comparable with gold in the aforementioned broadband range. We also critically evaluate the structural features that affect the quality factor of the plasmon resonance and we provide rules of thumb for the selection and growth of materials for nitride plasmonics.

  18. Nanoscratching of nylon 66-based ternary nanocomposites

    International Nuclear Information System (INIS)

    Dasari, Aravind; Yu Zhongzhen; Mai Yiuwing

    2007-01-01

    The nanoscratch behavior of nylon 66/SEBS-g-MA/clay ternary nanocomposites produced by different blending protocols with contrasting microstructures is studied by using atomic force and transmission electron microscopy. A standard diamond Berkovich indenter is used for scratching and a low load of 1 mN, along with a low sliding velocity of 1 μm s -1 , are employed for this purpose. It is shown that in order to resist penetration it is more important to have exfoliated clay in the continuous nylon matrix during nanoscratching than to have the clay in the dispersed soft rubber domains. The results obtained also explain the preferred usage of ternary nanocomposites compared to binary nanocomposites, particularly nylon 66/exfoliated clay nanocomposites. This research extends current basic knowledge and provides new insights on the nature of nanoscale processes that occur during nanoscratching of polymer nanocomposites. Critical questions are raised on the relationships between the penetration depth and material deformation and damage left behind the moving indenter

  19. Irregular Homogeneity Domains in Ternary Intermetallic Systems

    Directory of Open Access Journals (Sweden)

    Jean-Marc Joubert

    2015-12-01

    Full Text Available Ternary intermetallic A–B–C systems sometimes have unexpected behaviors. The present paper examines situations in which there is a tendency to simultaneously form the compounds ABx, ACx and BCx with the same crystal structure. This causes irregular shapes of the phase homogeneity domains and, from a structural point of view, a complete reversal of site occupancies for the B atom when crossing the homogeneity domain. This work reviews previous studies done in the systems Fe–Nb–Zr, Hf–Mo–Re, Hf–Re–W, Mo–Re–Zr, Re–W–Zr, Cr–Mn–Si, Cr–Mo–Re, and Mo–Ni–Re, and involving the topologically close-packed Laves, χ and σ phases. These systems have been studied using ternary isothermal section determination, DFT calculations, site occupancy measurement using joint X-ray, and neutron diffraction Rietveld refinement. Conclusions are drawn concerning this phenomenon. The paper also reports new experimental or calculated data on Co–Cr–Re and Fe–Nb–Zr systems.

  20. Metal semiconductor contacts and devices

    CERN Document Server

    Cohen, Simon S; Einspruch, Norman G

    1986-01-01

    VLSI Electronics Microstructure Science, Volume 13: Metal-Semiconductor Contacts and Devices presents the physics, technology, and applications of metal-semiconductor barriers in digital integrated circuits. The emphasis is placed on the interplay among the theory, processing, and characterization techniques in the development of practical metal-semiconductor contacts and devices.This volume contains chapters that are devoted to the discussion of the physics of metal-semiconductor interfaces and its basic phenomena; fabrication procedures; and interface characterization techniques, particularl

  1. Physical principles of semiconductor detectors

    International Nuclear Information System (INIS)

    Micek, S.L.

    1979-01-01

    The general properties of semiconductors with respect to the possibilities of their use as the ionization radiation detectors are discussed. Some chosen types of semiconductor junctions and their characteristics are briefly presented. There are also discussed the physical phenomena connected with the formation of barriers in various types of semiconductor counters. Finally, the basic properties of three main types of semiconductor detectors are given. (author)

  2. Handbook of luminescent semiconductor materials

    CERN Document Server

    Bergman, Leah

    2011-01-01

    Photoluminescence spectroscopy is an important approach for examining the optical interactions in semiconductors and optical devices with the goal of gaining insight into material properties. With contributions from researchers at the forefront of this field, Handbook of Luminescent Semiconductor Materials explores the use of this technique to study semiconductor materials in a variety of applications, including solid-state lighting, solar energy conversion, optical devices, and biological imaging. After introducing basic semiconductor theory and photoluminescence principles, the book focuses

  3. Scientific communications: Re-Os sulfide (bornite, chalcopyrite, and pyrite) systematics of the carbonate-hosted copper deposits at ruby creek, southern brooks range, Alaska

    Science.gov (United States)

    Selby, D.; Kelley, K.D.; Hitzman, M.W.; Zieg, J.

    2009-01-01

    New Re-Os data for chalcopyrite, bornite, and pyrite from the carbonate-hosted Cu deposit at Ruby Creek (Bornite), Alaska, show extremely high Re abundances (hundreds of ppb, low ppm) and contain essentially no common Os. The Re-Os data provide the first absolute ages of ore formation for the carbonate-hosted Ruby Creek Cu-(Co) deposit and demonstrate that the Re-Os systematics of pyrite, chalcopyrite, and bornite are unaffected by greenschist metamorphism. The Re-Os data show that the main phase of Cu mineralization pre dominantly occurred at 384 ?? 4.2 Ma, with an earlier phase possibly at ???400 Ma. The Re-Os data are consistent with the observed paragenetic sequence and coincide with zircon U-Pb ages from igneous rocks within the Ambler metallogenic belt, some of which are spatially and genetically associated with regional volcanogenic massive sulfide deposits. The latter may suggest a temporal link between regional magmatism and hydrothermal mineralization in the Ambler district. The utility of bornite and chalcopyrite, in addition to pyrite, contributes to a new understanding of Re-Os geochronology and permits a refinement of the genetic model for the Ruby Creek deposit. ?? 2009 Society of Economices Geologists, Inc.

  4. Attachment of Acidithiobacillus ferrooxidans and Leptospirillum ferriphilum cultured under varying conditions to pyrite, chalcopyrite, low-grade ore and quartz in a packed column reactor.

    Science.gov (United States)

    Africa, Cindy-Jade; van Hille, Robert P; Harrison, Susan T L

    2013-02-01

    The attachment of Acidithiobacillus ferrooxidans and Leptospirillum ferriphilum spp. grown on ferrous medium or adapted to a pyrite mineral concentrate to four mineral substrata, namely, chalcopyrite and pyrite concentrates, a low-grade chalcopyrite ore (0.5 wt%) and quartzite, was investigated. The quartzite represented a typical gangue mineral and served as a control. The attachment studies were carried out in a novel particle-coated column reactor. The saturated reactor containing glass beads, which were coated with fine mineral concentrates, provided a quantifiable surface area of mineral concentrate and maintained good fluid flow. A. ferrooxidans and Leptospirillum spp. had similar attachment characteristics. Enhanced attachment efficiency occurred with bacteria grown on sulphide minerals relative to those grown on ferrous sulphate in an ore-free environment. Selective attachment to sulphide minerals relative to gangue materials occurred, with mineral adapted cultures attaching to the minerals more efficiently than ferrous grown cultures. Mineral-adapted cultures showed highest levels of attachment to pyrite (74% and 79% attachment for A. ferrooxidans and L. ferriphilum, respectively). This was followed by attachment of mineral-adapted cultures to chalcopyrite (63% and 58% for A. ferrooxidans and L. ferriphilum, respectively). A. ferrooxidans and L. ferriphilum exhibited lower levels of attachment to low-grade ore and quartz relative to the sulphide minerals.

  5. Characteristics of Cu isotopes from chalcopyrite-rich black smoker chimneys at Brothers volcano, Kermadec arc, and Niuatahi volcano, Lau basin

    Science.gov (United States)

    Berkenbosch, H. A.; de Ronde, C. E. J.; Paul, B. T.; Gemmell, J. B.

    2015-10-01

    We analysed primary chalcopyrite from modern seafloor `black smoker' chimneys to investigate high-temperature hydrothermal Cu isotope fractionation unaffected by metamorphism. Samples came from nine chimneys collected from Brothers volcano, Kermadec arc, and Niuatahi volcano, Lau backarc basin. This is the first known study of Cu isotopes from submarine intraoceanic arc/backarc volcanoes, with both volcanoes discharging significant amounts of magmatic volatiles. Our results ( n = 22) range from δ65Cu = -0.03 to 1.44 ± 0.18 ‰ (2 sd), with the majority of samples between ˜0.00 and 0.50 ‰. We interpret this cluster ( n = 17) of lower δ65Cu values as representing a mantle source for the chimney Cu, in agreement with δ65Cu values for mantle rocks. The few higher δ65Cu values (>0.90 ‰) occur (1) within the same chimneys as lower values, (2) randomly distributed within the chimneys (i.e. near the top and bottom, interior and exterior), and (3) within chalcopyrite of approximately the same age (responsible for the observed isotopic fractionation. When compared to global δ65Cu data for primary chalcopyrite, volcanic arc chimneys are most similar to porphyry copper deposits that also form from magmatic-hydrothermal processes in convergent tectonic settings.

  6. Nonlinear Elasticity of Doped Semiconductors

    Science.gov (United States)

    2017-02-01

    AFRL-RY-WP-TR-2016-0206 NONLINEAR ELASTICITY OF DOPED SEMICONDUCTORS Mark Dykman and Kirill Moskovtsev Michigan State University...2016 4. TITLE AND SUBTITLE NONLINEAR ELASTICITY OF DOPED SEMICONDUCTORS 5a. CONTRACT NUMBER FA8650-16-1-7600 5b. GRANT NUMBER 5c. PROGRAM...vibration amplitude. 15. SUBJECT TERMS semiconductors , microresonators, microelectromechanical 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF

  7. Intense terahertz excitation of semiconductors

    CERN Document Server

    Ganichev, S D

    2006-01-01

    This work presents the first comprehensive treatment of high-power terahertz applications to semiconductors and low-dimensional semiconductor structures. Terahertz properties of semiconductors are in the centre of scientific activities because of the need of high-speed electronics.

  8. Semiconductor radiation detectors device physics

    CERN Document Server

    Lutz, Gerhard

    1999-01-01

    Describes the field of modern semiconductor detectors used for energy and position measurement radiation. This book includes an introduction to semiconductor physics. It explains the principles of semiconductor radiation detectors, followed by formal quantitative analysis. It also covers electronic signal readout.

  9. Semiconductors for plasmonics and metamaterials

    DEFF Research Database (Denmark)

    Naik, G.V.; Boltasseva, Alexandra

    2010-01-01

    with semiconductors can alleviate these problems if only semiconductors could exhibit negative real permittivity. Aluminum doped zinc oxide (AZO) is a low loss semiconductor that can show negative real permittivity in the NIR. A comparative assessment of AZO-based plasmonic devices such as superlens and hyperlens...

  10. Multinary wurtzite-type oxide semiconductors: present status and perspectives

    Science.gov (United States)

    Suzuki, Issei; Omata, Takahisa

    2017-01-01

    Oxide-based optoelectronic devices have been limited in applicable wavelength to the near-UV region because there are few viable binary wurtzite-type oxides, but ternary wurtzite-type (β-NaFeO2-type) oxides are promising materials to expand the applicable wavelengths of these devices. In the past decade, many attractive properties of β-NaFeO2-type oxide semiconductors have been revealed, such as the band-engineering of ZnO by alloying with β-LiGaO2 and β-AgGaO2, the photocatalytic activities of β-AgGaO2 and β-AgAlO2, and the discovery that β-CuGaO2 is suitable for thin-film solar-cell absorbers. In this review article, we consider previous studies of β-NaFeO2-type oxide semiconductors—β-LiGaO2, β-AgGaO2, β-AgAlO2, β-CuGaO2—and their alloys with ZnO, and discuss their structural features, optical and electrical properties, and the relationship between their crystal structures and electronic band structures. We describe the outlook of β-NaFeO2-type oxide semiconductors and the remaining issues that hinder the development of optoelectronic devices made from β-NaFeO2-type oxide semiconductors.

  11. Construction of RGO/CdIn2S4/g-C3N4 ternary hybrid with enhanced photocatalytic activity for the degradation of tetracycline hydrochloride

    Science.gov (United States)

    Xiao, Peng; Jiang, Deli; Ju, Lixin; Jing, Junjie; Chen, Min

    2018-03-01

    Although RGO shows great advantage in promoting charge separation and transfer of semiconductor, construction of an efficient RGO-incorporated photocatalyst is still challenging. Herein, RGO was employed to construct novel RGO/CdIn2S4/g-C3N4 (donated as RGO/CIS/CN) ternary photocatalyst by a facile hydrothermal method for the degradation of tetracycline hydrochloride (TC). The RGO/CIS/CN ternary photocatalyst showed significantly enhanced photocatalytic activity towards the degradation of TC as compared to the binary CIS/CN, CIS/CN, and CN/RGO. The photoluminescence and photocurrent response results indicate that this enhanced photocatalytic activity can be mainly ascribed to the improved charge separation and transfer efficiency. Based on the radical trapping and electron spin resonance results, the superoxide radicals and holes are proposed to play an important role in the degradation of TC over RGO/CIS/CN ternary photocatalyst. This work paves new opportunities for the synthesis of RGO-incorporated ternary photocatalyst as an efficient photocatalyst for the degradation of organic contaminant.

  12. Semiconductor detector physics

    International Nuclear Information System (INIS)

    Equer, B.

    1987-01-01

    Comprehension of semiconductor detectors follows comprehension of some elements of solid state physics. They are recalled here, limited to the necessary physical principles, that is to say the conductivity. P-n and MIS junctions are discussed in view of their use in detection. Material and structure (MOS, p-n, multilayer, ..) are also reviewed [fr

  13. Biexcitons in semiconductor microcavities

    DEFF Research Database (Denmark)

    Borri, P.; Langbein, W.; Woggon, U.

    2003-01-01

    In this paper, the present status of the experimental study of the optical properties of biexcitons in semiconductor microcavities is reviewed. In particular, a detailed investigation of a polariton-biexciton transition in a high-quality single quantum well GaAs/AlGaAs microcavity is reported...

  14. Investigation of Electrical and Optical Properties of Bulk III-V Ternary Semiconductors

    Science.gov (United States)

    2009-03-01

    Time Dependent Annealing Study of Silicon Implanted Aluminum Gallium Nitride,” Master’s Thesis, Air Force Institute of Technology (AU), Wright...Arsenide, Indium Gallium Antimonide , Electrical Characterization, Optical Characterization, Hall Measurements, Mobility, Conductivity, Carrier

  15. Growth and luminescence of ternary semiconductor ZnCdSe nanowires by metalorganic chemical vapor deposition.

    Science.gov (United States)

    Zhang, X T; Liu, Z; Li, Quan; Hark, S K

    2005-09-29

    ZnCdSe alloy nanowires were successfully grown on the GaAs (100) substrate by metalorganic chemical vapor deposition using Au as a catalyst. The nanowires display two distinct types of morphology. The majority of them are straight, uniform in diameter, and have a smooth surface. However, a significant portion of them contain one or two constrictions along their length. The alloy is found to be rich in Zn; its composition, as determined from X-ray diffraction and energy-dispersive X-ray microanalysis, is close to Zn(0.9)Cd(0.1)Se. The peak energy of its room temperature near-band-edge photoluminescence is also consistent with this composition. X-ray diffraction pattern and transmission electron microscopy find both types of nanowires to be single crystalline, have the metastable wurtzite structure, and a growth direction along 100. The presence of an Au-Cd-Zn alloy particle at the tip of the nanowires supports vapor-liquid-solid as the growth mechanism. The appearance of constrictions in some of the nanowires is found to be linked to the existence of structural defects, possibly stacking faults, during growth.

  16. Optical fingerprints of Y2 ordering in III–V ternary semiconductor alloys

    International Nuclear Information System (INIS)

    Chen, Dongguo; Ravindra, N M

    2013-01-01

    In this paper, we report the Y2 ordering induced changes in the crystal field splitting, spin–orbit splitting and band gap for Al x Ga 1−x As, Ga x In 1−x As, Ga x In 1−x P, GaAs x Sb 1−x and InP x Sb 1−x using first-principles calculations. These values and the valence band splittings E 12 , E 13 for these materials are provided as a function of the ordering parameter η. The trends of these properties among materials are explained. The optical fingerprints of Y2 ordering are then compared with those of other available structures and the experimental data. (paper)

  17. In situ investigation of wet chemical processes for chalcopyrite solar cells by L-edge XAS under ambient conditions

    Energy Technology Data Exchange (ETDEWEB)

    Greil, Stefanie M. [Helmholtz-Zentrum Berlin fuer Materialien und Energie, Albert-Einstein-Strasse 15, 12489 Berlin (Germany); Lauermann, Iver, E-mail: Iver.lauermann@helmholtz-berlin.d [Helmholtz-Zentrum Berlin fuer Materialien und Energie, Albert-Einstein-Strasse 15, 12489 Berlin (Germany); Ennaoui, Ahmed; Kropp, Timo; Lange, Kathrin M.; Weber, Matthieu [Helmholtz-Zentrum Berlin fuer Materialien und Energie, Albert-Einstein-Strasse 15, 12489 Berlin (Germany); Aziz, Emad F., E-mail: Emad.Aziz@helmholtz-berlin.d [Helmholtz-Zentrum Berlin fuer Materialien und Energie, Albert-Einstein-Strasse 15, 12489 Berlin (Germany)

    2010-02-15

    Two instrumental setups for in situ soft X-ray absorption spectroscopy in liquid systems are demonstrated in this work. One for investigating chemical reactions in solutions and a new one for the solid component of a liquid / (as in both / absorber) solid interface. We used these setups for investigating two production processes for chalcopyrite solar cells under ambient conditions, probing the L-edge of Zn and Cu. The first one is a flow cell with a silicon nitride membrane to study the chemical bath deposition process for Cd-free buffer layers. Examining the electronic structure of involved Zn complexes allows to determine the exact reaction mechanism taking place during this process. The second setup is a rotating disk for investigating the bath/absorber interface upon the etching process of superficial binary copper compounds of the absorber as a function of time. The time resolution of the chemical reaction demonstrated in this study ranges from the second to minute time scale.

  18. In situ investigation of wet chemical processes for chalcopyrite solar cells by L-edge XAS under ambient conditions

    International Nuclear Information System (INIS)

    Greil, Stefanie M.; Lauermann, Iver; Ennaoui, Ahmed; Kropp, Timo; Lange, Kathrin M.; Weber, Matthieu; Aziz, Emad F.

    2010-01-01

    Two instrumental setups for in situ soft X-ray absorption spectroscopy in liquid systems are demonstrated in this work. One for investigating chemical reactions in solutions and a new one for the solid component of a liquid / (as in both / absorber) solid interface. We used these setups for investigating two production processes for chalcopyrite solar cells under ambient conditions, probing the L-edge of Zn and Cu. The first one is a flow cell with a silicon nitride membrane to study the chemical bath deposition process for Cd-free buffer layers. Examining the electronic structure of involved Zn complexes allows to determine the exact reaction mechanism taking place during this process. The second setup is a rotating disk for investigating the bath/absorber interface upon the etching process of superficial binary copper compounds of the absorber as a function of time. The time resolution of the chemical reaction demonstrated in this study ranges from the second to minute time scale.

  19. In situ investigation of wet chemical processes for chalcopyrite solar cells by L-edge XAS under ambient conditions

    Science.gov (United States)

    Greil, Stefanie M.; Lauermann, Iver; Ennaoui, Ahmed; Kropp, Timo; Lange, Kathrin M.; Weber, Matthieu; Aziz, Emad F.

    2010-02-01

    Two instrumental setups for in situ soft X-ray absorption spectroscopy in liquid systems are demonstrated in this work. One for investigating chemical reactions in solutions and a new one for the solid component of a liquid / (as in both / absorber) solid interface. We used these setups for investigating two production processes for chalcopyrite solar cells under ambient conditions, probing the L-edge of Zn and Cu. The first one is a flow cell with a silicon nitride membrane to study the chemical bath deposition process for Cd-free buffer layers. Examining the electronic structure of involved Zn complexes allows to determine the exact reaction mechanism taking place during this process. The second setup is a rotating disk for investigating the bath/absorber interface upon the etching process of superficial binary copper compounds of the absorber as a function of time. The time resolution of the chemical reaction demonstrated in this study ranges from the second to minute time scale.

  20. Impact on sediments and water by release of copper from chalcopyrite bearing rock due to acidic mine drainage

    Science.gov (United States)

    Shukla, Anoop Kant; Pradhan, Manoj; Tiwari, Onkar Nath

    2018-04-01

    Mining activity causes transition of rock-mass from its original position in earth into open environment. The action of environmental elements such air, water, microorganisms leads to oxidation of minerals which constitute the rock. The oxidation of sulphide minerals in presence of moisture releases acidic mine discharge (AMD). The acidic nature of AMD causes leaching of metals from rock minerals. Dissolution of other minerals may occur upon reaction with AMD. Chalcopyrite (CuFeS2) undergoes oxidation in acidic condition releasing copper among other products. This study reveals contamination of copper in sediment samples and seepage water from the tailing dam of a large copper project in located in central India. Elevation was studied using GIS to ascertain to the topographic elevation of tailing dam area. It was located at relatively high altitude causing seepage to flow away from tailing dam. The seepage water from tailing dam was found to be acidic with mean pH value of 4.0 and elevated copper content. Similarly, sediments from seepage water flow displayed elevated copper concentration. The copper concentration in seepage water was found with a mean value of 10.73 mg/l. The sediments from seepage water flow also displayed elevated copper concentration with mean value of 26.92 g/kg. This indicates impact on sediments by release of copper due to acidic mine drainage.

  1. [Construction of Three-Dimensional Isobologram for Ternary Pollutant Mixtures].

    Science.gov (United States)

    2015-12-01

    Tongji University, Shanghai 200092, China) Isobolographic analysis was widely used in the interaction assessment of binary mixtures. However, how to construct a three-dimensional (3D) isobologram for the assessment of toxicity interaction within ternary mixtures is still not reported up to date. The main purpose of this paper is to develop a 3D isobologram where the relative concentrations of three components are acted as three coordinate axes in 3D space to examine the toxicity interaction within ternary mixtures. Taking six commonly used pesticides in China, including three herbicides (2, 4-D, desmetryne and simetryn) and three insecticides ( dimethoate, imidacloprid and propoxur) as the mixture components, the uniform design ray procedure (UD-Ray) was used to rationally design the concentration composition of various components in the ternary mixtures so that effectively and comprehensively reflected the variety of actual environmental concentrations. The luminescent inhibition toxicities of single pesticides and their ternary mixtures to Vibrio fischeri at various concentration levels were determined by the microplate toxicity analysis. Selecting concentration addition (CA) as the addition reference, 3D isobolograms were constructed to study the toxicity interactions of various ternary mixtures. The results showed that the 3D isobologram could clearly and directly exhibit the toxicity interactions of ternary mixtures, and extend the use of isobolographic analysis into the ternary mixtures.

  2. Ternary phosphates of rubidium-cesium-rare earth element

    International Nuclear Information System (INIS)

    Mel'nikov, P.P.; Carrillo-Eredero, H.D.; Efremov, V.A.; Komissarova, L.N.; Quiroga, E.

    1986-01-01

    This article examines the possibility of the existence of ternary phosphates of the rare earth elements (REE) containing two large alkali cations in order to establish the morphological and physicochemical characteristics in the entire group of ternary REE phosphates. The synthesis of the ternary rubidium-cesium-REE phosphates was carried out with molten charges that did not contain an excess of components. Analysis for the uncommon alkali cations was done by the atomic absorption technique; for holmium, by complexometric titration; and for phosphorus, by gravimetry as NH 4 CdPO 4 . The data obtained fully confirm the composition of Rb 2 CsLn(PO 4 ) 2

  3. A Three-dimensional Topological Model of Ternary Phase Diagram

    International Nuclear Information System (INIS)

    Mu, Yingxue; Bao, Hong

    2017-01-01

    In order to obtain a visualization of the complex internal structure of ternary phase diagram, the paper realized a three-dimensional topology model of ternary phase diagram with the designed data structure and improved algorithm, under the guidance of relevant theories of computer graphics. The purpose of the model is mainly to analyze the relationship between each phase region of a ternary phase diagram. The model not only obtain isothermal section graph at any temperature, but also extract a particular phase region in which users are interested. (paper)

  4. Can Time Reversal be tested in ternary fission?

    International Nuclear Information System (INIS)

    Goennenwein, F.; Jesinger, P.; Koetzle, A.; Mutterer, M.; Kalben, J. von; Trzaska, W.H.; Petrov, G.A.; Gagarski, A.M.; Danilyan, G.; Pavlov, V.S.; Nesvizhevsky, V.; Zimmer, O.

    2000-01-01

    Ternary fission of 233 U and 235 U induced by cold polarized neutrons has been investigated. Several correlations between neutron spin and the momenta of fission fragments and ternary particles were analyzed. These correlations are probing time reversal invariance, parity non-conservation and left-right asymmetries. Results for all three correlations from the reaction 233 U(n,f) are presented. Especially the outcome in the searches for time reversal correlations and left-right asymmetries is unexpected. A huge effect observed formally as a violation of time reversal is most probably simulated by specific properties of the emission mechanism for ternary particles

  5. Facile Synthesis of Ternary Boron Carbonitride Nanotubes

    Directory of Open Access Journals (Sweden)

    Luo Lijie

    2009-01-01

    Full Text Available Abstract In this study, a novel and facile approach for the synthesis of ternary boron carbonitride (B–C–N nanotubes was reported. Growth occurred by heating simple starting materials of boron powder, zinc oxide powder, and ethanol absolute at 1150 °C under a mixture gas flow of nitrogen and hydrogen. As substrate, commercial stainless steel foil with a typical thickness of 0.05 mm played an additional role of catalyst during the growth of nanotubes. The nanotubes were characterized by SEM, TEM, EDX, and EELS. The results indicate that the synthesized B–C–N nanotubes exhibit a bamboo-like morphology and B, C, and N elements are homogeneously distributed in the nanotubes. A catalyzed vapor–liquid–solid (VLS mechanism was proposed for the growth of the nanotubes.

  6. Magnetism and crystal fields in ternary superconductors

    International Nuclear Information System (INIS)

    Shenoy, G.K.; Crabtree, G.W.; Niarchos, D.; Behroozi, F.; Dunlap, B.D.; Hinks, D.; Noakes, D.R.

    1982-01-01

    In this paper, the present state of knowledge of crystalline electric field (CEF) in two important classes of ternary superconductors has been described. It is clear that in understanding the superconducting and magnetic behavior of RERh 4 B 4 , the CEF plays a very important role. Considerable importance has been given to the specific heat Schottky anomalies in deducing the position and degeneracy of various CEF levels. Interpretation of these data is made difficult because of complicated subtraction of lattice, electronic and superconducting specific heats. Furthermore, the purity of the sample is important in such studies. It is known that a few percent of Rh-B/sub x/, RERh 3 B 2 and RERh 6 B 4 are commonly present in RERh 4 B 4 , while Mo-Ch/sub x/, RE-Ch/sub x/ and RE 2 O 2 Ch phases occur in Chevrel phase compounds. Only single-crystal samples will lead to dependable specific heat data

  7. The ternary system: Silicon-tantalum-uranium

    Energy Technology Data Exchange (ETDEWEB)

    Rogl, Peter, E-mail: peter.franz.rogl@univie.ac.a [Institute of Physical Chemistry, University of Vienna, A-1090 Wien, Waehringerstrasse 42 (Austria); Noel, Henri [Laboratoire de Chimie du Solide et Materiaux, UMR-CNRS 6226, Universite de Rennes I, Avenue du General Leclerc, F-35042 Rennes, Cedex (France)

    2010-09-01

    Phase equilibria in the ternary system Si-Ta-U have been established in an isothermal section at 1000 {sup o}C by optical microscopy, electron probe microanalysis and X-ray diffraction. Two novel ternary compounds were observed and were characterised by X-ray powder Rietveld refinement: stoichiometric {tau}{sub 1}-U{sub 2}Ta{sub 3}Si{sub 4} (U{sub 2}Mo{sub 3}Si{sub 4}-type, P2{sub 1}/c; a = 0.70011(1), b = 0.70046(1), c = 0.68584(1) nm, ss = 109.38(1); R{sub F} = 0.073, X-ray powder Rietveld refinement) and {tau}{sub 2}-U{sub 2-x}Ta{sub 3+x}Si{sub 4} at x {approx} 0.30 (Sc{sub 2}Re{sub 3}Si{sub 4}-type = partially ordered Zr{sub 5}Si{sub 4}-type, P4{sub 1}2{sub 1}2; a = b = 0.69717(3)(1), c = 1.28709(4) nm; R{sub F} = 0.056; X-ray single crystal data). Mutual solubility of U-silicides and Ta-silicides are found to be very small i.e. below about 1 at.%. Due to the equilibrium tie-line Ta{sub 2}Si-U(Ta), no compatibility exists between the U-rich silicides U{sub 3}Si or U{sub 3}Si{sub 2} and tantalum metal. Single crystals obtained from alloys slowly cooled from liquid (2000 {sup o}C), yielded a fully ordered compound U{sub 2}Ta{sub 2}Si{sub 3}C (unique structure type; Pmna, a = 0.68860(1); b = 2.17837(4); c = 0.69707(1) nm; R{sub F2} = 0.048).

  8. Compound semiconductor device modelling

    CERN Document Server

    Miles, Robert

    1993-01-01

    Compound semiconductor devices form the foundation of solid-state microwave and optoelectronic technologies used in many modern communication systems. In common with their low frequency counterparts, these devices are often represented using equivalent circuit models, but it is often necessary to resort to physical models in order to gain insight into the detailed operation of compound semiconductor devices. Many of the earliest physical models were indeed developed to understand the 'unusual' phenomena which occur at high frequencies. Such was the case with the Gunn and IMPATI diodes, which led to an increased interest in using numerical simulation methods. Contemporary devices often have feature sizes so small that they no longer operate within the familiar traditional framework, and hot electron or even quantum­ mechanical models are required. The need for accurate and efficient models suitable for computer aided design has increased with the demand for a wider range of integrated devices for operation at...

  9. Semiconductor physics an introduction

    CERN Document Server

    Seeger, Karlheinz

    1999-01-01

    Semiconductor Physics - An Introduction - is suitable for the senior undergraduate or new graduate student majoring in electrical engineering or physics. It will also be useful to solid-state scientists and device engineers involved in semiconductor design and technology. The text provides a lucid account of charge transport, energy transport and optical processes, and a detailed description of many devices. It includes sections on superlattices and quantum well structures, the effects of deep-level impurities on transport, the quantum Hall effect and the calculation of the influence of a magnetic field on the carrier distribution function. This 6th edition has been revised and corrected, and new sections have been added to different chapters.

  10. Basic semiconductor physics

    CERN Document Server

    Hamaguchi, Chihiro

    2017-01-01

    This book presents a detailed description of basic semiconductor physics. The text covers a wide range of important phenomena in semiconductors, from the simple to the advanced. Four different methods of energy band calculations in the full band region are explained: local empirical pseudopotential, non-local pseudopotential, KP perturbation and tight-binding methods. The effective mass approximation and electron motion in a periodic potential, Boltzmann transport equation and deformation potentials used for analysis of transport properties are discussed. Further, the book examines experiments and theoretical analyses of cyclotron resonance in detail. Optical and transport properties, magneto-transport, two-dimensional electron gas transport (HEMT and MOSFET) and quantum transport are reviewed, while optical transition, electron-phonon interaction and electron mobility are also addressed. Energy and electronic structure of a quantum dot (artificial atom) are explained with the help of Slater determinants. The...

  11. Single frequency semiconductor lasers

    CERN Document Server

    Fang, Zujie; Chen, Gaoting; Qu, Ronghui

    2017-01-01

    This book systematically introduces the single frequency semiconductor laser, which is widely used in many vital advanced technologies, such as the laser cooling of atoms and atomic clock, high-precision measurements and spectroscopy, coherent optical communications, and advanced optical sensors. It presents both the fundamentals and characteristics of semiconductor lasers, including basic F-P structure and monolithic integrated structures; interprets laser noises and their measurements; and explains mechanisms and technologies relating to the main aspects of single frequency lasers, including external cavity lasers, frequency stabilization technologies, frequency sweeping, optical phase locked loops, and so on. It paints a clear, physical picture of related technologies and reviews new developments in the field as well. It will be a useful reference to graduate students, researchers, and engineers in the field.

  12. Images through semiconductors

    International Nuclear Information System (INIS)

    Anon.

    1986-01-01

    Improved image processing techniques are constantly being developed for television and for scanners using X-rays or other radiation for industrial or medical applications, etc. As Erik Heijne of CERN explains here, particle physics too has its own special requirements for image processing. The increasing use of semiconductor techniques for handling measurements down to the level of a few microns provides another example of the close interplay between scientific research and technological development. (orig.).

  13. Quantum Confined Semiconductors

    Science.gov (United States)

    2015-02-01

    RCR    , (5) which considers all elastic scattering events on the energy shell kk EEE   , which is appropriate for all scattering...fluctuations in semiconductor superlattices using a magneto -transport technique,” Superlattices and Microstructures 15, 225-228 (1994). 12. I. Dharssi and...εyy is consistently slightly tensile (≈ -1%), which agreed with theoretical calculations of εyy based on published values of elastic constants. An

  14. Muonium states in semiconductors

    International Nuclear Information System (INIS)

    Patterson, B.D.

    1987-01-01

    There is a brief summary of what is known about the muonium states isotropic, anisotropic and diamagnetic in diamond and zincblende semiconductors. The report deals with muonium spectroscopy, including the formation probabilities, hyperfine parameters and electronic g-factors of the states. The dynamics of the states is treated including a discussion of the transition from isotropic Mu to anisotropic Mu in diamond, temperature-dependent linewidthes in silicon and germanium and effects of daping and radiation damage

  15. Semiconductor projectile impact detector

    Science.gov (United States)

    Shriver, E. L. (Inventor)

    1977-01-01

    A semiconductor projectile impact detector is described for use in determining micrometeorite presence, as well as its flux and energy comprising a photovoltaic cell which generates a voltage according to the light and heat emitted by the micrometeorites upon impact. A counter and peak amplitude measuring device were used to indicate the number of particules which strike the surface of the cell as well as the kinetic energy of each of the particles.

  16. Nonradiative recombination in semiconductors

    CERN Document Server

    Abakumov, VN; Yassievich, IN

    1991-01-01

    In recent years, great progress has been made in the understandingof recombination processes controlling the number of excessfree carriers in semiconductors under nonequilibrium conditions. As a result, it is now possible to give a comprehensivetheoretical description of these processes. The authors haveselected a number of experimental results which elucidate theunderlying physical problems and enable a test of theoreticalmodels. The following topics are dealt with: phenomenological theory ofrecombination, theoretical models of shallow and deep localizedstates, cascade model of carrier captu

  17. Semiconductor detectors. Recent evolution

    International Nuclear Information System (INIS)

    Siffert, P.

    1977-01-01

    The recent evolution as well as the problems appearing in the use of semiconductor counters in both X and γ-ray as well as heavy ions spectroscopy are reviewed. For the photon counters the discussion is limited to cadmium telluride and mercuric iodide room temperature diodes, whereas for heavy ions, identification by means of thin ΔE/Δx counters and some problems related to the pulse amplitude in E detectors are considered [fr

  18. Survey of semiconductor physics

    CERN Document Server

    Böer, Karl W

    1992-01-01

    Any book that covers a large variety of subjects and is written by one author lacks by necessity the depth provided by an expert in his or her own field of specialization. This book is no exception. It has been written with the encouragement of my students and colleagues, who felt that an extensive card file I had accumulated over the years of teaching solid state and semiconductor physics would be helpful to more than just a few of us. This file, updated from time to time, contained lecture notes and other entries that were useful in my research and permitted me to give to my students a broader spectrum of information than is available in typical textbooks. When assembling this material into a book, I divided the top­ ics into material dealing with the homogeneous semiconductor, the subject of the previously published Volume 1, and the inhomoge­ neous semiconductor, the subject of this Volume 2. In order to keep the book to a manageable size, sections of tutorial character which can be used as text for a g...

  19. Densities and Excess Molar Volume for the Ternary Systems (1 ...

    African Journals Online (AJOL)

    methylimidazolium methyl sulphate ([BMIM]+[MeSO4]-) were determined. The ternary systems studied were ... The results are interpreted in terms of the alcohol chain length and the intermolecular interactions. KEYWORDS Density, excess molar ...

  20. Kinetic study of lithium-cadmium ternary amalgam decomposition

    International Nuclear Information System (INIS)

    Cordova, M.H.; Andrade, C.E.

    1992-01-01

    The effect of metals, which form stable lithium phase in binary alloys, on the formation of intermetallic species in ternary amalgams and their effect on thermal decomposition in contact with water is analyzed. Cd is selected as ternary metal, based on general experimental selection criteria. Cd (Hg) binary amalgams are prepared by direct contact Cd-Hg, whereas Li is formed by electrolysis of Li OH aq using a liquid Cd (Hg) cathodic well. The decomposition kinetic of Li C(Hg) in contact with 0.6 M Li OH is studied in function of ageing and temperature, and these results are compared with the binary amalgam Li (Hg) decomposition. The decomposition rate is constant during one hour for binary and ternary systems. Ageing does not affect the binary systems but increases the decomposition activation energy of ternary systems. A reaction mechanism that considers an intermetallic specie participating in the activated complex is proposed and a kinetic law is suggested. (author)

  1. Features of programming in DSSP for the ternary machine

    Directory of Open Access Journals (Sweden)

    Alexey А. Burtsev

    2017-12-01

    Full Text Available In article characteristic properties of the Dialogue System for Structured Programming (DSSP in which it significantly differs from the traditional languages (Pascal, C which are usually used for development of a basic course of programming are emphasized. And also the new possibilities of program creation which can be effectively realized on the ternary computer and which are provided now by programming system DSSP for TVM — the ternary virtual machine are considered.

  2. Tricolore. A flexible color scale for ternary compositions

    DEFF Research Database (Denmark)

    2018-01-01

    tricolore is an R library providing a flexible color scale for the visualization of three-part/ternary compositions. Its main functionality is to color-code any ternary composition as a mixture of three primary colours and to draw a suitable color-key. tricolore flexibly adapts to different...... visualisation challenges via - discrete and continuous color support - support for unbalanced compositional data via centering - support for data with very narrow range via scaling - hue, chroma and lightness options...

  3. Thin film reactions on alloy semiconductor substrates

    Energy Technology Data Exchange (ETDEWEB)

    Olson, D.A.

    1990-11-01

    The interactions between Pt and In{sub .53}Ga{sub .47}As have been studied. In{sub .53}Ga{sub .47}As substrates with 70nm Pt films were encapsulated in SiO{sub 2}, and annealed up to 600{degree}C in flowing forming gas. The composition and morphology of the reaction product phases were studied using x-ray diffraction, Auger depth profiling, and transmission electron microscopy. The reaction kinetics were examined with Rutherford Backscattering. Results show that Pt/In{sub .53}Ga{sub .47}As reacts to form many of the reaction products encountered in the Pt/GaAs and Pt/InP reactions: PtGa, Pt{sub 3}Ga, and PtAs{sub 2}. In addition, a ternary phase, Pt(In:Ga){sub 2}, develops, which is a solid solution between PtIn{sub 2} and PtGa{sub 2}. The amount of Ga in the ternary phase increases with annealing temperature, which causes a decrease in the lattice parameter of the phase. The reaction products show a tendency to form layered structures, especially for higher temperatures and longer annealing times. Unlike the binary case, the PtAs{sub 2}, phase is randomly oriented on the substrate, and is intermingle with a significant amount of Pt(In:Ga){sub 2}. Following Pt/In{sub .53}Ga{sub .47}As reactions, two orientation relationships between the Pt(In:Ga){sub 2} product phase and the substrate were observed, despite the large mismatch with the substrate ({approximately}8%). For many metal/compound semiconductor interactions, the reaction rate is diffusion limited, i.e. exhibits a parabolic dependence on time. An additional result of this study was the development of an In-rich layer beneath the reacted layer. The Auger depth profile showed a substantial increase in the sample at this layer. This is a significant result for the production of ohmic contacts, as the Schottky barrier height in this system lower for higher In concentrations. 216 refs.

  4. Structural, elastic, electronic, bonding, and optical properties of BeAZ2 (A = Si, Ge, Sn; Z = P, As) chalcopyrites

    International Nuclear Information System (INIS)

    Fahad, Shah; Murtaza, G.; Ouahrani, T.; Khenata, R.; Yousaf, Masood; Omran, S.Bin; Mohammad, Saleh

    2015-01-01

    A first principles density functional theory (DFT) technique is used to study the structural, chemical bonding, electronic and optical properties of BeAZ 2 (A = Si, Ge, Sn; Z = P, As) chalcopyrite materials. The calculated parameters are in good agreement with the available experimental results. The lattice constants and the equilibrium volume increased as we moved from Si to Ge to Sn, whereas the c/a and internal parameters u decreased by shifting the cation from P to As. These compounds are elastically stable. An investigation of the band gap using the WC-GGA, EV-GGA, PBE-GGA and mBJ-metaGGA potentials suggested that BeSiP 2 and BeSiAs 2 are direct band gap compounds, whereas BeGeP 2, BeGeAs 2, BeSnP 2, BeSnAs 2 are indirect band gap compounds. The energy band gaps decreased by changing B from Si to Sn and increased by changing the anion C from P to As. The bonding among the cations and anions is primarily ionic. In the optical properties, the real and imaginary parts of the dielectric functions, reflectivity and optical conductivity have been studied over a wide energy range. - Highlights: • The compounds are studied by FP-LAPW method within mBJ approximation. • All of the studied materials show isotropic behaviour. • All the compounds show direct band gap nature. • Bonding nature is mostly covalent among the studied compounds. • High absorption peaks and reflectivity ensures there utility in optoelectronic devices

  5. Charge distribution in the ternary fragmentation of {sup 252}Cf

    Energy Technology Data Exchange (ETDEWEB)

    Senthil Kannan, M.T.; Balasubramaniam, M. [Bharathiar University, Department of Physics, Coimbatore (India)

    2017-08-15

    We present here, for the first time, a study on ternary fragmentation charge distribution of {sup 252}Cf using the convolution integral method and the statistical theory. The charge distribution for all possible charge combinations of a ternary breakup are grouped as a bin containing different mass partitions. Different bins corresponding to various third fragments with mass numbers from A{sub 3} = 16 to 84 are identified with the available experimental masses. The corresponding potential energy surfaces are calculated using the three cluster model for the two arrangements A{sub 1} + A{sub 2} + A{sub 3} and A{sub 1} + A{sub 3} + A{sub 2}. The ternary fragmentation yield values are calculated for the ternary combination from each bin possessing minimum potential energy. The yields of the resulting ternary combinations as a function of the charge numbers of the three fragments are analyzed for both the arrangements. The calculations are carried out at different excitation energies of the parent nucleus. For each excitation energy the temperature of the three fragments are iteratively computed conserving the total energy. The distribution of fragment temperatures corresponding to different excitation energies for some fixed third fragments are discussed. The presence of the closed shell nucleus Sn in the favourable ternary fragmentation is highlighted. (orig.)

  6. Impact of ternary blends of biodiesel on diesel engine performance

    Directory of Open Access Journals (Sweden)

    Prem Kumar

    2016-06-01

    Full Text Available The Pongamia and waste cooking oils are the main non edible oils for biodiesel production in India. The aim of the present work is to evaluate the fuel properties and investigate the impact on engine performance using Pongamia and waste cooking biodiesel and their ternary blend with diesel. The investigation of the fuel properties shows that Pongamia biodiesel and waste cooking biodiesel have poor cold flow property. This will lead to starting problem in the engine operation. To overcome this problem the ternary blends of diesel, waste cooking biodiesel and Pongamia biodiesel are prepared. The cloud and pour point for ternary blend, (WCB20:PB20:D60 were found to be 7 °C and 6.5 °C which are comparable to cloud and pour point of diesel 6 °C and 5 °C, respectively. The result of the test showed that brake specific fuel consumption for Pongamia biodiesel and waste cooking biodiesel is higher than ternary blend, (WCB20:PB20:D60 due to their lower energy content. The brake thermal efficiency of ternary blend and diesel is comparable while the Pongamia and waste cooking biodiesel have low efficiency. The result of investigation showed that ternary blend can be developed as alternate fuel.

  7. 75 FR 49526 - Freescale Semiconductor, Inc., Technical Information Center, Tempe, AZ; Freescale Semiconductor...

    Science.gov (United States)

    2010-08-13

    ... Semiconductor, Inc., Technical Information Center, Tempe, AZ; Freescale Semiconductor, Inc., Technical... October 1, 2009, applicable to workers of Freescale Semiconductor, Inc., Technical Information Center..., Massachusetts location of Freescale Semiconductor, Inc., Technical Information Center. The intent of the...

  8. New developments in power semiconductors

    Science.gov (United States)

    Sundberg, G. R.

    1983-06-01

    This paper represents an overview of some recent power semiconductor developments and spotlights new technologies that may have significant impact for aircraft electric secondary power. Primary emphasis will be on NASA-Lewis-supported developments in transistors, diodes, a new family of semiconductors, and solid-state remote power controllers. Several semiconductor companies that are moving into the power arena with devices rated at 400 V and 50 A and above are listed, with a brief look at a few devices.

  9. Maxwell-Stefan diffusion coefficient estimation for ternary systems: an ideal ternary alcohol system.

    Science.gov (United States)

    Allie-Ebrahim, Tariq; Zhu, Qingyu; Bräuer, Pierre; Moggridge, Geoff D; D'Agostino, Carmine

    2017-06-21

    The Maxwell-Stefan model is a popular diffusion model originally developed to model diffusion of gases, which can be considered thermodynamically ideal mixtures, although its application has been extended to model diffusion in non-ideal liquid mixtures as well. A drawback of the model is that it requires the Maxwell-Stefan diffusion coefficients, which are not based on measurable quantities but they have to be estimated. As a result, numerous estimation methods, such as the Darken model, have been proposed to estimate these diffusion coefficients. However, the Darken model was derived, and is only well defined, for binary systems. This model has been extended to ternary systems according to two proposed forms, one by R. Krishna and J. M. van Baten, Ind. Eng. Chem. Res., 2005, 44, 6939-6947 and the other by X. Liu, T. J. H. Vlugt and A. Bardow, Ind. Eng. Chem. Res., 2011, 50, 10350-10358. In this paper, the two forms have been analysed against the ideal ternary system of methanol/butan-1-ol/propan-1-ol and using experimental values of self-diffusion coefficients. In particular, using pulsed gradient stimulated echo nuclear magnetic resonance (PGSTE-NMR) we have measured the self-diffusion coefficients in various methanol/butan-1-ol/propan-1-ol mixtures. The experimental values of self-diffusion coefficients were then used as the input data required for the Darken model. The predictions of the two proposed multicomponent forms of this model were then compared to experimental values of mutual diffusion coefficients for the ideal alcohol ternary system. This experimental-based approach showed that the Liu's model gives better predictions compared to that of Krishna and van Baten, although it was only accurate to within 26%. Nonetheless, the multicomponent Darken model in conjunction with self-diffusion measurements from PGSTE-NMR represents an attractive method for a rapid estimation of mutual diffusion in multicomponent systems, especially when compared to exhaustive

  10. Band structure of semiconductors

    CERN Document Server

    Tsidilkovski, I M

    2013-01-01

    Band Structure of Semiconductors provides a review of the theoretical and experimental methods of investigating band structure and an analysis of the results of the developments in this field. The book presents the problems, methods, and applications in the study of band structure. Topics on the computational methods of band structure; band structures of important semiconducting materials; behavior of an electron in a perturbed periodic field; effective masses and g-factors for the most commonly encountered band structures; and the treatment of cyclotron resonance, Shubnikov-de Haas oscillatio

  11. Physics of Organic Semiconductors

    CERN Document Server

    Brütting, Wolfgang

    2005-01-01

    Filling the gap in the literature currently available, this book presents an overview of our knowledge of the physics behind organic semiconductor devices. Contributions from 18 international research groups cover various aspects of this field, ranging from the growth of organic layers and crystals, their electronic properties at interfaces, their photophysics and electrical transport properties to the application of these materials in such different devices as organic field-effect transistors, photovoltaic cells and organic light-emitting diodes. From the contents:. * Excitation Dynamics in O

  12. Semiconductor ionizino. radiation detectors

    International Nuclear Information System (INIS)

    1982-01-01

    Spectrometric semiconductor detectors of ionizing radiation with the electron-hole junction, based on silicon and germanium are presented. The following parameters are given for the individual types of germanium detectors: energy range of detected radiation, energy resolution given as full width at half maximum (FWHM) and full width at one tenth of maximum (FWTM) for 57 Co and 60 Co, detection sensitivity, optimal voltage, and electric capacitance at optimal voltage. For silicon detectors the value of FWHM for 239 Pu is given, the sensitive area and the depth of the sensitive area. (E.S.)

  13. Semiconductor characterization for optoelectronics

    Energy Technology Data Exchange (ETDEWEB)

    Miner, C.J. [Bell Northern Research Ltd., Ottawa, ON (Canada)

    1996-03-01

    Scanning reflectance spectroscopy, scanning photoluminescence, and double crystal x-ray diffraction mapping are all specialized non-destructive characterization tools which monitor the advanced materials used in the development of high speed optoelectronics. Each technology was described and their application in the assessment of III-V semiconductor composition, layer thickness and defect density was demonstrated. The new techniques have been optimized for speed, to make high spatial resolution mapping practical. Since the tests are non-destructive, frequent monitoring is possible. 11 refs., 7 figs.

  14. Basic properties of semiconductors

    CERN Document Server

    Landsberg, PT

    2013-01-01

    Since Volume 1 was published in 1982, the centres of interest in the basic physics of semiconductors have shifted. Volume 1 was called Band Theory and Transport Properties in the first edition, but the subject has broadened to such an extent that Basic Properties is now a more suitable title. Seven chapters have been rewritten by the original authors. However, twelve chapters are essentially new, with the bulk of this work being devoted to important current topics which give this volume an almost encyclopaedic form. The first three chapters discuss various aspects of modern band theory and the

  15. Layered semiconductor neutron detectors

    Science.gov (United States)

    Mao, Samuel S; Perry, Dale L

    2013-12-10

    Room temperature operating solid state hand held neutron detectors integrate one or more relatively thin layers of a high neutron interaction cross-section element or materials with semiconductor detectors. The high neutron interaction cross-section element (e.g., Gd, B or Li) or materials comprising at least one high neutron interaction cross-section element can be in the form of unstructured layers or micro- or nano-structured arrays. Such architecture provides high efficiency neutron detector devices by capturing substantially more carriers produced from high energy .alpha.-particles or .gamma.-photons generated by neutron interaction.

  16. Semiconductor Properties Near Interfaces.

    Science.gov (United States)

    1980-07-31

    Sputtered from Semiconductors", Proc. 13th Annual Conference of the Microbeam Analysis Society, 1978. 4. J. C. Potosky and D. B. Wittry, "The Secondary...Ion Optics of a Quadru- pole Ion Microprobe", Proc. 13th Annual Conference of the Microbeam Analysis Society, 1978. 5. F. Guo and D. B. Wittry, "Use...of Specimen Current Integration in SIMS", Proc. 13th Annual Conference of the Microbeam Analysis Society, 1978. 6. D. B. Wittry, ’. Y. Yin, and R. A

  17. Hydrogen in semiconductors

    CERN Document Server

    Pankove, Jacques I

    1991-01-01

    Hydrogen plays an important role in silicon technology, having a profound effect on a wide range of properties. Thus, the study of hydrogen in semiconductors has received much attention from an interdisciplinary assortment of researchers. This sixteen-chapter volume provides a comprehensive review of the field, including a discussion of hydrogenation methods, the use of hydrogen to passivate defects, the use of hydrogen to neutralize deep levels, shallow acceptors and shallow donors in silicon, vibrational spectroscopy, and hydrogen-induced defects in silicon. In addition to this detailed cove

  18. Anisotropy in the ternary cold fission

    CERN Document Server

    Delion, D S; Greiner, W

    2003-01-01

    We describe the spontaneous ternary cold fission of sup 2 sup 5 sup 2 Cf, accompanied by sup 4 He, sup 1 sup 0 Be and sup 1 sup 4 C within a stationary scattering formalism. We show that the light cluster should be born in the neck region. It decays from the first resonant eigenstate in the Coulomb plus harmonic oscillator potential, centred in this region and eccentric with respect to the symmetry axis. This description gives a simple answer to the question why the averaged values in the energy spectra of emitted clusters are close to each other, in spite of different Coulomb barriers. We have shown that the angular distribution of the emitted light particle is strongly connected with its deformation and the equatorial distance. Experimental angular distributions can be explained by the spherical shapes of emitted clusters, except for a deformed sup 1 sup 0 Be. We also predicted some dependences of half-lives for such tri-nuclear systems upon potential parameters.

  19. Two-layer synchronized ternary quantum-dot cellular automata wire crossings

    Science.gov (United States)

    2012-01-01

    Quantum-dot cellular automata are an interesting nanoscale computing paradigm. The introduction of the ternary quantum-dot cell enabled ternary computing, and with the recent development of a ternary functionally complete set of elementary logic primitives and the ternary memorizing cell design of complex processing structures is becoming feasible. The specific nature of the ternary quantum-dot cell makes wire crossings one of the most problematic areas of ternary quantum-dot cellular automata circuit design. We hereby present a two-layer wire crossing that uses a specific clocking scheme, which ensures the crossed wires have the same effective delay. PMID:22507371

  20. Wavelength modulation spectroscopy of semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Kohn, S.E.

    1977-10-01

    The use of modulation spectroscopy to study the electronic properties of solids has been very productive. The construction of a wide range Wavelength Modulation Spectrometer to study the optical properties of solids is described in detail. Extensions of the working range of the spectrometer into the vacuum ultraviolet are discussed. Measurements of the reflectivity and derivative reflectivity spectra of the lead chalcogenides, the chalcopyrite ZnGeP/sub 2/, the layer compounds GaSe and GaS and their alloys, the ferroelectric SbSI, layer compounds SnS/sub 2/ and SnSe/sub 2/, and HfS/sub 2/ were made. The results of these measurements are presented along with their interpretation in terms of band structure calculations.

  1. Application of quaternary phase diagrams to compound semiconductor processing. Progress report, April 1, 1988--December 31, 1988

    Energy Technology Data Exchange (ETDEWEB)

    Schwartzman, A.

    1988-12-31

    This paper considers the application of quaternary phase diagrams to understanding and predicting the behavior of II-VI thin film interfaces in photovoltaic devices under annealing conditions. Examples, listed in a table, include semiconductor/insulator/semiconductor (SIS) layered structures, II-VI/II-VI and III-V/II-VI epitaxial heterojunctions and oxidation of ternary compounds. Solid solubility is taken into account for quaternary phase diagrams of semiconductor systems. Using free energies of formation, a method to calculate the quaternary phase diagrams was developed. The Ga-As-II-VI and Cd-Te-Zn-O phase diagrams are reviewed as examples of quaternary phase diagrams without and with solid solubility.

  2. Photoluminescence polarization anisotropy for studying long-range structural ordering within semiconductor multi-atomic alloys and organic crystals

    Energy Technology Data Exchange (ETDEWEB)

    Prutskij, T.; Percino, J. [Instituto de Ciencias, BUAP, Privada 17 Norte, No 3417, col. San Miguel Huyeotlipan, 72050, Puebla, Pue. (Mexico); Orlova, T. [Department of Chemical and Biochemical Engineering, University of Notre Dame, Notre Dame, IN (United States); Vavilova, L. [Ioffe Physical-Technical Institute, 26 Polytekhnicheskaya, St Petersburg 194021, Russian Federation (Russian Federation)

    2013-12-04

    Long-range structural ordering within multi-component semiconductor alloys and organic crystals leads to significant optical anisotropy and, in particular, to anisotropy of the photoluminescence (PL) emission. The PL emission of ternary and quaternary semiconductor alloys is polarized if there is some amount of the atomic ordering within the crystal structure. We analyze the polarization of the PL emission from the quaternary GaInAsP semiconductor alloy grown by Liquid Phase Epitaxy (LPE) and conclude that it could be caused by low degree atomic ordering within the crystal structure together with the thermal biaxial strain due to difference between the thermal expansion coefficients of the layer and the substrate. We also study the state of polarization of the PL from organic crystals in order to identify different features of the crystal PL spectrum.

  3. Squeezed light in semiconductors

    CERN Document Server

    Ward, M B

    2001-01-01

    Experimental evidence is presented for the generation of photon-number squeezed states of light as a result of multi-photon absorption. Photon-number squeezing as a result of non-linear absorption has long been predicted and results have been obtained utilising two very different material systems: (i) an AIGaAs waveguide in which high optical intensities can be maintained over a relatively long interaction length of 2 mm; (ii) the organic polymer p-toluene sulphonate polydiacetylene that is essentially a one-dimensional semiconductor possessing a highly nonlinear optical susceptibility. The resulting nonlinear absorption is shown to leave the transmitted light in a state that is clearly nonclassical, exhibiting photon-number fluctuations below the shot-noise limit. Tuning the laser wavelength across the half-bandgap energy has enabled a comparison between two- and three-photon processes in the semiconductor waveguide. The correlations created between different spectral components of a pulsed beam of light as ...

  4. Single filament semiconductor laser

    International Nuclear Information System (INIS)

    Botez, D.

    1980-01-01

    A semiconductor laser comprising: a body of semiconductor material including a substrate having a surface and a pair of spaced, substantially parallel dove-tailed shaped grooves in said surface, said body having a pair of end surfaces between which said grooves extend, said end surfaces being reflective to light with at least one of said end surfaces being partially transparent to light a first epitaxial layer over said surface of the substrate and the surfaces of the grooves, said first epitaxial layer having a flat surface portion over the portion of the substrate surface between the grooves, a thin second epitaxial layer over said first epitaxial layer, a third epitaxial layer over said second epitaxial layer, said first and third epitaxial layers being of opposite conductivity types and the second epitaxial layer being the active recombination region of the laser with the light being generated therein in the vicinity of the portion which is over the flat surface portion of the first epitaxial layer, and a pair of contacts on said body with one contact being over said third epitaxial body and the other being on said substrate

  5. Doped semiconductor nanocrystal junctions

    Energy Technology Data Exchange (ETDEWEB)

    Borowik, Ł.; Mélin, T., E-mail: thierry.melin@isen.iemn.univ-lille1.fr [Institut d’Electronique, de Microélectronique et de Nanotechnologie, CNRS-UMR8520, Avenue Poincaré, F-59652 Villeneuve d’Ascq (France); Nguyen-Tran, T.; Roca i Cabarrocas, P. [Laboratoire de Physique des Interfaces et des Couches Minces, CNRS-UMR7647, Ecole Polytechnique, F-91128 Palaiseau (France)

    2013-11-28

    Semiconductor junctions are the basis of electronic and photovoltaic devices. Here, we investigate junctions formed from highly doped (N{sub D}≈10{sup 20}−10{sup 21}cm{sup −3}) silicon nanocrystals (NCs) in the 2–50 nm size range, using Kelvin probe force microscopy experiments with single charge sensitivity. We show that the charge transfer from doped NCs towards a two-dimensional layer experimentally follows a simple phenomenological law, corresponding to formation of an interface dipole linearly increasing with the NC diameter. This feature leads to analytically predictable junction properties down to quantum size regimes: NC depletion width independent of the NC size and varying as N{sub D}{sup −1/3}, and depleted charge linearly increasing with the NC diameter and varying as N{sub D}{sup 1/3}. We thus establish a “nanocrystal counterpart” of conventional semiconductor planar junctions, here however valid in regimes of strong electrostatic and quantum confinements.

  6. Process for producing chalcogenide semiconductors

    Science.gov (United States)

    Noufi, R.; Chen, Y.W.

    1985-04-30

    A process for producing chalcogenide semiconductor material is disclosed. The process includes forming a base metal layer and then contacting this layer with a solution having a low pH and containing ions from at least one chalcogen to chalcogenize the layer and form the chalcogenide semiconductor material.

  7. Progress in semiconductor drift detectors

    International Nuclear Information System (INIS)

    Rehak, P.; Walton, J.; Gatti, E.

    1985-01-01

    Progress in testing semiconductor drift detectors is reported. Generally better position and energy resolutions were obtained than resolutions published previously. The improvement is mostly due to new electronics better matched to different detectors. It is shown that semiconductor drift detectors are becoming versatile and reliable detectors for position and energy measurements

  8. Terahertz Nonlinear Optics in Semiconductors

    DEFF Research Database (Denmark)

    Turchinovich, Dmitry; Hvam, Jørn Märcher; Hoffmann, Matthias C.

    2013-01-01

    We demonstrate the nonlinear optical effects – selfphase modulation and saturable absorption of a single-cycle THz pulse in a semiconductor. Resulting from THz-induced modulation of Drude plasma, these nonlinear optical effects, in particular, lead to self-shortening and nonlinear spectral...... breathing of a single-cycle THz pulse in a semiconductor....

  9. Optical coherent control in semiconductors

    DEFF Research Database (Denmark)

    Østergaard, John Erland; Vadim, Lyssenko; Hvam, Jørn Märcher

    2001-01-01

    of quantum control including the recent applications to semiconductors and nanostructures. We study the influence of inhomogeneous broadening in semiconductors on CC results. Photoluminescence (PL) and the coherent emission in four-wave mixing (FWM) is recorded after resonant excitation with phase...

  10. Electronic structure of semiconductor interfaces

    International Nuclear Information System (INIS)

    Herman, F.

    1983-01-01

    The study of semiconductor interfaces is one of the most active and exciting areas of current semiconductor research. Because interfaces play a vital role in modern semiconductor technology (integrated circuits, heterojunction lasers, solar cells, infrared detectors, etc.), there is a strong incentive to understand interface properties at a fundamental level and advance existing technology thereby. At the same time, technological advances such as molecular beam epitaxy have paved the way for the fabrication of semiconductor heterojunctions and superlattices of novel design which exhibit unusual electronic, optical, and magnetic properties and offer unique opportunities for fundamental scientific research. A general perspective on this subject is offered treating such topics as the atomic and electronic structure of semiconductor surfaces and interfaces; oxidation and oxide layers; semiconductor heterojunctions and superlattices; rectifying metal-semiconductor contacts; and interface reactions. Recent progress is emphasized and some future directions are indicated. In addition, the role that large-scale scientific computation has played in furthering our theoretical understanding of semiconductor surfaces and interfaces is discussed. Finally, the nature of theoretical models, and the role they play in describing the physical world is considered. (Author) [pt

  11. II-VI semiconductor compounds

    CERN Document Server

    1993-01-01

    For condensed matter physicists and electronic engineers, this volume deals with aspects of II-VI semiconductor compounds. Areas covered include devices and applications of II-VI compounds; Co-based II-IV semi-magnetic semiconductors; and electronic structure of strained II-VI superlattices.

  12. Semiconductor photocatalysis principles and applications

    CERN Document Server

    Kisch, Horst

    2014-01-01

    Focusing on the basic principles of semiconductor photocatalysis, this book also gives a brief introduction to photochemistry, photoelectrochemistry, and homogeneous photocatalysis. In addition, the author - one of the leading authorities in the field - presents important environmental and practical aspects. A valuable, one-stop source for all chemists, material scientists, and physicists working in this area, as well as novice researchers entering semiconductor photocatalysis.

  13. Quantum transport in semiconductor nanowires

    NARCIS (Netherlands)

    Van Dam, J.

    2006-01-01

    This thesis describes a series of experiments aimed at understanding the low-temperature electrical transport properties of semiconductor nanowires. The semiconductor nanowires (1-100 nm in diameter) are grown from nanoscale gold particles via a chemical process called vapor-liquid-solid (VLS)

  14. Electrostatic Doping in Semiconductor Devices

    NARCIS (Netherlands)

    Gupta, Gaurav; Rajasekharan, Bijoy; Hueting, Raymond J.E.

    2017-01-01

    To overcome the limitations of chemical doping in nanometer-scale semiconductor devices, electrostatic doping (ED) is emerging as a broadly investigated alternative to provide regions with a high electron or hole density in a semiconductor device. In this paper, we review various reported ED

  15. Luminescence studies of semiconductor electrodes

    NARCIS (Netherlands)

    Kelly, J.J.; Kooij, Ernst S.; Meulenkamp, E.A.

    1999-01-01

    In this paper we review our recent results of in-situ luminescence studies of semiconductor electrodes. Three classes of materials are considered: single crystal compound semiconductors, porous silicon and semiconducting oxides doped with luminescent ions. We show how photoluminescence (PL) and

  16. Low temperature transport and thermodynamic properties of the Zintl compound Yb11AlSb9: A new Kondo lattice semiconductor

    International Nuclear Information System (INIS)

    Magnavita, E.T.; Rettori, C.; Osorio-Guillén, J.M.; Ferreira, F.F.; Mendonça-Ferreira, L.; Avila, M.A.; Ribeiro, R.A.

    2016-01-01

    A thorough transport and thermodynamic investigation of flux-grown single crystals of the ternary Zintl phase Yb 11 AlSb 9 , combined with first-principles density functional theory calculations, shows that this compound is a metal above T ≈ 100 K and a semiconductor with small hybridization gap at low-T. The general behavior resembles those of Kondo lattice semiconductors, although some of the measured properties are strongly sample dependent, as often seen in hybridized f-electron materials. We thus suggest that Yb 11 AlSb 9 can be considered as a new Yb-based Kondo lattice semiconductor joining the family of strongly correlated electron systems. - Highlights: • First characterization at low temperatures of Yb 11 AlSb 9 . • Yb 11 AlSb 9 has a small, field dependent hybridization gap at low-T. • Yb 11 AlSb 9 can be considered as a new Kondo lattice semiconductor.

  17. Nuclear Electrical and Optical Studies of Hydrogen in Semiconductors.

    CERN Multimedia

    Dietrich, M; Toulemonde, M

    2002-01-01

    During the last years, the understanding of H and its interaction with dopant atoms in Si, Ge and III-V semiconductors has improved considerably concerning the stability of the formed complexes their structural arrangements, and the implications of this interaction on the electrical properties of the semiconductors " passivation " The perturbed angular correlation technique (PAC) has contributed to the understanding of this phenomena on an atomistic scale using radioactive isotopes provided by ISOLDE. \\\\ \\\\The aim of the proposed experiments is twofold: \\\\ \\\\\\begin{enumerate} \\item The H passivation mechanism of acceptors in GaN and ternary III-V compounds (AlGaAs, GaInP, AlGaN) shall be investigated, using the PAC probe atom $^{111m}$Cd as a 'representative' of group II-B metal acceptors. The problems addressed in these technological important systems are microscopic structure, formation and stability of the hydrogen correlated complexes as function of doping and stoichiometry (i.e. the size of the band gap)...

  18. Ion channeling study of defects in multicomponent semiconductor compounds

    International Nuclear Information System (INIS)

    Turos, A.; Nowicki, L.; Stonert, A.

    2002-01-01

    Compound semiconductor crystals are of great technological importance as basic materials for production of modern opto- and microelectronic devices. Ion implantation is one of the principal techniques for heterostructures processing. This paper reports the results of the study of defect formation and transformation in binary and ternary semiconductor compounds subjected to ion implantation with ions of different mass and energy. The principal analytical technique was He-ion channeling. The following materials were studied: GaN and InGaN epitaxial layers. First the semi empirical method of channeling spectra analysis for ion implanted multicomponent single crystal was developed. This method was later complemented by the more sophisticated method based on the Monte Carlo simulation of channeling spectra. Next, the damage buildup in different crystals and epitaxial layers as a function of the implantation dose was studied for N, Mg, Te, and Kr ions. The influence of the substrate temperature on the defect transformations was studied for GaN epitaxial layers implanted with Mg ions. Special attention was devoted to the study of growth conditions of InGaN/GaN/sapphire heterostructures, which are important component of the future blue laser diodes. In-atom segregation and tetragonal distortion of the epitaxial layer were observed and characterized. Next problem studied was the incorporation of hydrogen atoms in GaAs and GaN. Elastic recoil detection (ERDA) and nuclear reaction analysis (NRA) were applied for the purpose. (author)

  19. Organic semiconductors in a spin

    CERN Document Server

    Samuel, I

    2002-01-01

    A little palladium can go a long way in polymer-based light-emitting diodes. Inorganic semiconductors such as silicon and gallium arsenide are essential for countless applications in everyday life, ranging from PCs to CD players. However, while they offer unrivalled computational speed, inorganic semiconductors are also rigid and brittle, which means that they are less suited to applications such as displays and flexible electronics. A completely different class of materials - organic semiconductors - are being developed for these applications. Organic semiconductors have many attractive features: they are easy to make, they can emit visible light, and there is tremendous scope for tailoring their properties to specific applications by changing their chemical structure. Research groups and companies around the world have developed a wide range of organic-semiconductor devices, including transistors, light-emitting diodes (LEDs), solar cells and lasers. (U.K.)

  20. Constitution of the ternary system Cr–Ni–Ti

    International Nuclear Information System (INIS)

    Krendelsberger, Natalja; Weitzer, Franz; Du, Yong; Schuster, Julius C.

    2013-01-01

    Highlights: •Reaction scheme and liquidus surface for Cr-Ni-Ti are given. •In the ternary the C14-type Laves phase coexists with the liquid phase. •Two ternary eutectics are identified. -- Abstract: The nature of solid–liquid phase equilibria in the ternary system Cr–Ni–Ti was investigated using electron microscopy, energy dispersive spectroscopy, X-ray diffraction, and differential thermal analysis. Literature data on solid state phase equilibria are confirmed. The Cr 2 Ti Laves phase modifications coexisting with Ni–Ti phases are clarified to be hexagonal C14-type and cubic C15-type. The C14-type Laves phase γCr 2 Ti is found to coexist with the liquid phase. It forms in the pseudobinary peritectic reaction p max1 from L + β(Cr,Ti) at 1389 °C. On further cooling γCr 2 Ti + NiTi solidify at 1202 °C in the pseudobinary eutectic e max2 . In the Cr-rich part of the system ternary eutectics occur at 1216 °C (E 1 : L = Ni 3 Ti + (Ni) + β(Cr,Ti)) and 1100 °C (E 2 : L = NiTi + Ni 3 Ti + β(Cr,Ti)), respectively. No ternary eutectic is found in the Ti-rich part. Rather the eutectic trough ends in the binary eutectic L = NiTi 2 + β(Ti)

  1. Ternary fission of spontaneously fissile uranium isomers excited by neutrons

    International Nuclear Information System (INIS)

    Makarenko, V.E.; Molchanov, Y.D.; Otroshchenko, G.A.; Yan'kov, G.B.

    1989-01-01

    Spontaneously fissile isomers (SFI) of uranium were excited in the reactions 236,238 U(n,n') at an average neutron energy 4.5 MeV. A pulsed electrostatic accelerator and time analysis of the fission events were used. Fission fragments were detected by the scintillation method, and long-range particles from fission were detected by an ionization method. The relative probability of fission of nuclei through a spontaneously fissile isomeric state was measured: (1.30±0.01)·10 -4 ( 236 U) and (1.48±0.02)·10 -4 ( 238 U). Half-lives of the isomers were determined: 121±2 nsec (the SFI 236 U) and 267±13 nsec (the SFI 238 U). In study of the ternary fission of spontaneously fissile isotopes of uranium it was established that the probability of the process amounts to one ternary fission per 163±44 binary fissions of the SFI 236 U and one ternary fission per 49±14 binary fissions of the SFI 238 U. The substantial increase of the probability of ternary fission of SFI of uranium in comparison with the case of ternary fission of nuclei which are not in an isomeric state may be related to a special nucleon configuration of the fissile isomers of uranium

  2. Ion implantation for semiconductors

    International Nuclear Information System (INIS)

    Grey-Morgan, T.

    1995-01-01

    Full text: Over the past two decades, thousands of particle accelerators have been used to implant foreign atoms like boron, phosphorus and arsenic into silicon crystal wafers to produce special embedded layers for manufacturing semiconductor devices. Depending on the device required, the atomic species, the depth of implant and doping levels are the main parameters for the implantation process; the selection and parameter control is totally automated. The depth of the implant, usually less than 1 micron, is determined by the ion energy, which can be varied between 2 and 600 keV. The ion beam is extracted from a Freeman or Bernas type ion source and accelerated to 60 keV before mass analysis. For higher beam energies postacceleration is applied up to 200 keV and even higher energies can be achieved by mass selecting multiplycharged ions, but with a corresponding reduction in beam output. Depending on the device to be manufactured, doping levels can range from 10 10 to 10 15 atoms/cm 2 and are controlled by implanter beam currents in the range up to 30mA; continuous process monitoring ensures uniformity across the wafer of better than 1 % . As semiconductor devices get smaller, additional sophistication is required in the design of the implanter. The silicon wafers charge electrically during implantation and this charge must be dissipated continuously to reduce the electrical stress in the device and avoid destructive electrical breakdown. Electron flood guns produce low energy electrons (below 10 electronvolts) to neutralize positive charge buildup and implanter design must ensure minimum contamination by other isotopic species and ensure low internal sputter rates. The pace of technology in the semiconductor industry is such that implanters are being built now for 256 Megabit circuits but which are only likely to be widely available five years from now. Several specialist companies manufacture implanter systems, each costing around US$5 million, depending on the

  3. In situ monitoring the growth of thin-film ZnS/Zn (S,O) bilayer on Cu-chalcopyrite for high performance thin film solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Saez-Araoz, R.; Abou-Ras, D. [Helmholtz-Zentrum Berlin fuer Materialien und Energie GmbH, Solar Energy Division, Glienicker Strasse 100, 14109 Berlin (Germany); Niesen, T.P. [AVANCIS GmbH and Co KG Otto-Hahn-Ring 6, 81739 Munich (Germany); Neisser, A.; Wilchelmi, K. [SULFURCELL Solartechnik GmbH Barbara-McClintock-Strasse 11, 12489 Berlin (Germany); Lux-Steiner, M.Ch. [Helmholtz-Zentrum Berlin fuer Materialien und Energie GmbH, Solar Energy Division, Glienicker Strasse 100, 14109 Berlin (Germany); Ennaoui, A. [Helmholtz-Zentrum Berlin fuer Materialien und Energie GmbH, Solar Energy Division, Glienicker Strasse 100, 14109 Berlin (Germany)], E-mail: ennaoui@helmholtz-berlin.de

    2009-02-02

    This paper highlights the crucial role that the control of the chemical bath deposition (CBD) process plays for buffer production of Cu-chalcopyrite solar-cell devices. ZnS/Zn (S,O) bilayer was deposited on CuInS{sub 2} (CIS) and Cu(In,Ga)(SSe){sub 2} (CIGSSe) and monitored using turbidity measurements of the solution. The results were correlated to the X-ray photoemission spectra of the samples obtained by interruption of the process at sequential stages. Two different feature regimes were distinguished: In the first stage, a heterogeneous reaction takes place on the absorber resulting in the formation of pure ZnS. The second stage of the process is homogeneous, and the in-situ turbidity measurement shows a loss in the transmission of light through the CBD solution. The measured ZnL3M45M45 Auger-peaks, during this second stage of the process, show a shift of the kinetic energy from pure ZnS to a solid-solution ZnS/ZnO ('Zn (S,O)') with decreasing amount of sulfur. These results are supported by the observations from Energy-filtered transmission electron microscopy. This paper also demonstrates that monitoring of the CBD process combined with the basic understanding using surface and interface analysis have contributed to improve the reproducibility and to enhance the photovoltaic performance of Cu-chalcopyrite thin-film solar modules.

  4. In situ monitoring the growth of thin-film ZnS/Zn (S,O) bilayer on Cu-chalcopyrite for high performance thin film solar cells

    International Nuclear Information System (INIS)

    Saez-Araoz, R.; Abou-Ras, D.; Niesen, T.P.; Neisser, A.; Wilchelmi, K.; Lux-Steiner, M.Ch.; Ennaoui, A.

    2009-01-01

    This paper highlights the crucial role that the control of the chemical bath deposition (CBD) process plays for buffer production of Cu-chalcopyrite solar-cell devices. ZnS/Zn (S,O) bilayer was deposited on CuInS 2 (CIS) and Cu(In,Ga)(SSe) 2 (CIGSSe) and monitored using turbidity measurements of the solution. The results were correlated to the X-ray photoemission spectra of the samples obtained by interruption of the process at sequential stages. Two different feature regimes were distinguished: In the first stage, a heterogeneous reaction takes place on the absorber resulting in the formation of pure ZnS. The second stage of the process is homogeneous, and the in-situ turbidity measurement shows a loss in the transmission of light through the CBD solution. The measured ZnL3M45M45 Auger-peaks, during this second stage of the process, show a shift of the kinetic energy from pure ZnS to a solid-solution ZnS/ZnO ('Zn (S,O)') with decreasing amount of sulfur. These results are supported by the observations from Energy-filtered transmission electron microscopy. This paper also demonstrates that monitoring of the CBD process combined with the basic understanding using surface and interface analysis have contributed to improve the reproducibility and to enhance the photovoltaic performance of Cu-chalcopyrite thin-film solar modules

  5. Assessing the role of hydrogen in Fermi-level pinning in chalcopyrite and kesterite solar absorbers from first-principles calculations

    Science.gov (United States)

    Varley, J. B.; Lordi, V.; Ogitsu, T.; Deangelis, A.; Horsley, K.; Gaillard, N.

    2018-04-01

    Understanding the impact of impurities in solar absorbers is critical to engineering high-performance in devices, particularly over extended periods of time. Here, we use hybrid functional calculations to explore the role of hydrogen interstitial (Hi) defects in the electronic properties of a number of attractive solar absorbers within the chalcopyrite and kesterite families to identify how this common impurity may influence device performance. Our results identify that Hi can inhibit the highly p-type conditions desirable for several higher-band gap absorbers and that H incorporation could detrimentally affect the open-circuit voltage (Voc) and limit device efficiencies. Additionally, we find that Hi can drive the Fermi level away from the valence band edge enough to lead to n-type conductivity in a number of chalcopyrite and kesterite absorbers, particularly those containing Ag rather than Cu. We find that these effects can lead to interfacial Fermi-level pinning that can qualitatively explain the observed performance in high-Ga content CIGSe solar cells that exhibit saturation in the Voc with increasing band gap. Our results suggest that compositional grading rather than bulk alloying, such as by creating In-rich surfaces, may be a better strategy to favorably engineering improved thin-film photovoltaics with larger-band gap absorbers.

  6. Tunable optical properties of ZnCdTe2-xSex(x =0.625) chalcopyrite for photovoltaics; a mBJLDA approach

    Science.gov (United States)

    Kashyap, Manish K.; Paudyal, D.; Harmon, B. N.

    In the present study, we have performed ab-initio simulations of sp-element defect in ZnCdTe2-xSex (x =0.625) chalcopyrite to check the tuning of band gap as compared to the pristine case. The exchange and correlation (XC) effects are taken into account by an orbital independent modified Becke-Johnson (mBJ) potential as coupled with Local Density Approximation (LDA) for these calculations. The calculated energy band structures show a direct band gap at the point in the brillouin zone for the pristine as well as the defected case and the band gap decreases with inclusion of sp-disorder. The imaginary dielectric function predicts the optical band gap of pristine ZnCdTe2 very close to the experimental value and the results are in reasonable agreement without applying any scissor operator. With inclusion of sp-element defect, the optical spectra is tuned to optimal region, suitable for photovoltaics. It is apparent that mBJ functional is well suited for calculating electronic structure of pristine as well as defected ZnCdTe2chalcopyrite. MKK acknowledges financial support from UGC, India in the form of RAMAN Post-doctoral fellowship. This work at Ames Laboratory was supported by the DOE, Office of Basic Energy Sciences, Materials Sciences Division under contract No. DE-AC02-07CH11358.

  7. Expression of Critical Sulfur- and Iron-Oxidation Genes and the Community Dynamics During Bioleaching of Chalcopyrite Concentrate by Moderate Thermophiles.

    Science.gov (United States)

    Zhou, Dan; Peng, Tangjian; Zhou, Hongbo; Liu, Xueduan; Gu, Guohua; Chen, Miao; Qiu, Guanzhou; Zeng, Weimin

    2015-07-01

    Sulfate adenylyltransferase gene and 4Fe-4S ferredoxin gene are the key genes related to sulfur and iron oxidations during bioleaching system, respectively. In order to better understand the bioleaching and microorganism synergistic mechanism in chalcopyrite bioleaching by mixed culture of moderate thermophiles, expressions of the two energy metabolism genes and community dynamics of free and attached microorganisms were investigated. Specific primers were designed for real-time quantitative PCR to study the expression of these genes. Real-time PCR results showed that sulfate adenylyltransferase gene was more highly expressed in Sulfobacillus thermosulfidooxidans than that in Acidithiobacillus caldus, and expression of 4Fe-4S ferredoxin gene was higher in Ferroplasma thermophilum than that in S. thermosulfidooxidans and Leptospirillum ferriphilum. The results indicated that in the bioleaching system of chalcopyrite concentrate, sulfur and iron oxidations were mainly performed by S. thermosulfidooxidans and F. thermophilum, respectively. The community dynamics results revealed that S. thermosulfidooxidans took up the largest proportion during the whole period, followed by F. thermophilum, A. caldus, and L. ferriphilum. The CCA analysis showed that 4Fe-4S ferredoxin gene expression was mainly affected (positively correlated) by high pH and elevated concentration of ferrous ion, while no factor was observed to prominently influence the expression of sulfate adenylyltransferase gene.

  8. Enhanced charge separation in ternary P3HT/PCBM/CuInS2 nanocrystals hybrid solar cells.

    Science.gov (United States)

    Lefrançois, Aurélie; Luszczynska, Beata; Pepin-Donat, Brigitte; Lombard, Christian; Bouthinon, Benjamin; Verilhac, Jean-Marie; Gromova, Marina; Faure-Vincent, Jérôme; Pouget, Stéphanie; Chandezon, Frédéric; Sadki, Saïd; Reiss, Peter

    2015-01-15

    Geminate recombination of bound polaron pairs at the donor/acceptor interface is one of the major loss mechanisms in organic bulk heterojunction solar cells. One way to overcome Coulomb attraction between opposite charge carriers and to achieve their full dissociation is the introduction of high dielectric permittivity materials such as nanoparticles of narrow band gap semiconductors. We selected CuInS2 nanocrystals of 7.4 nm size, which present intermediate energy levels with respect to poly(3-hexylthiophene) (P3HT) and Phenyl-C61-butyric acid methyl ester (PCBM). Efficient charge transfer from P3HT to nanocrystals takes place as evidenced by light-induced electron spin resonance. Charge transfer between nanocrystals and PCBM only occurs after replacing bulky dodecanethiol (DDT) surface ligands with shorter 1,2-ethylhexanethiol (EHT) ligands. Solar cells containing in the active layer a ternary blend of P3HT:PCBM:CuInS2-EHT nanocrystals in 1:1:0.5 mass ratio show strongly improved short circuit current density and a higher fill factor with respect to the P3HT:PCBM reference device. Complementary measurements of the absorption properties, external quantum efficiency and charge carrier mobility indicate that enhanced charge separation in the ternary blend is at the origin of the observed behavior. The same trend is observed for blends using the glassy polymer poly(triarylamine) (PTAA).

  9. Theoretical investigation of the structural stabilities, optoelectronic properties and thermodynamic characteristics of GaPxSb1-x ternary alloys

    Science.gov (United States)

    Oumelaz, F.; Nemiri, O.; Boumaza, A.; Ghemid, S.; Meradji, H.; Bin Omran, S.; El Haj Hassan, F.; Rai, D. P.; Khenata, R.

    2017-12-01

    In this theoretical study, we have investigated the structural, phase transition, electronic, thermodynamic and optical properties of GaPxSb1-x ternary alloys. Our calculations are performed with the WIEN2k code based on density functional theory using the full-potential linearized augmented plane wave method. For the electron exchange-correlation potential, a generalized gradient approximation within Wu-Cohen scheme is considered. The recently developed Tran-Blaha modified Becke-Johnson potential has also been used to improve the underestimated band gap. The structural properties, including the lattice constants, the bulk moduli and their pressure derivatives are in very good agreement with the available experimental data and theoretical results. Several structural phase transitions were studied here to establish the stable structure and to predict the phase transition under hydrostatic pressure. The computed transition pressure (Pt) of the material of our interest from the zinc blende (B3) to the rock salt (B1) phase has been determined and found to agree well with the experimental and theoretical data. The calculated band structure shows that GaSb binary compound and the ternary alloys are direct band gap semiconductors. Optical parameters such as the dielectric constants and the refractive indices are calculated and analyzed. The thermodynamic results are also interpreted and analyzed.

  10. Density Functional Theory Modeling of Low-Loss Electron Energy-Loss Spectroscopy in Wurtzite III-Nitride Ternary Alloys.

    Science.gov (United States)

    Eljarrat, Alberto; Sastre, Xavier; Peiró, Francesca; Estradé, Sónia

    2016-06-01

    In the present work, the dielectric response of III-nitride semiconductors is studied using density functional theory (DFT) band structure calculations. The aim of this study is to improve our understanding of the features in the low-loss electron energy-loss spectra of ternary alloys, but the results are also relevant to optical and UV spectroscopy results. In addition, the dependence of the most remarkable features with composition is tested, i.e. applying Vegard's law to band gap and plasmon energy. For this purpose, three wurtzite ternary alloys, from the combination of binaries AlN, GaN, and InN, were simulated through a wide compositional range (i.e., Al x Ga1-x N, In x Al1-x N, and In x Ga1-x N, with x=[0,1]). For this DFT calculations, the standard tools found in Wien2k software were used. In order to improve the band structure description of these semiconductor compounds, the modified Becke-Johnson exchange-correlation potential was also used. Results from these calculations are presented, including band structure, density of states, and complex dielectric function for the whole compositional range. Larger, closer to experimental values, band gap energies are predicted using the novel potential, when compared with standard generalized gradient approximation. Moreover, a detailed analysis of the collective excitation features in the dielectric response reveals their compositional dependence, which sometimes departs from a linear behavior (bowing). Finally, an advantageous method for measuring the plasmon energy dependence from these calculations is explained.

  11. Semiconductor testing method

    International Nuclear Information System (INIS)

    Brown, Stephen.

    1992-01-01

    In a method of avoiding use of nuclear radiation, eg gamma rays, X-rays, electron beams, for testing semiconductor components for resistance to hard radiation, which hard radiation causes data corruption in some memory devices and 'latch-up' in others, similar fault effects can be achieved using a xenon or other 'light' flash gun even though the penetration of light is significantly less than that of gamma rays. The method involves treating a device with gamma radiation, measuring a particular fault current at the onset of a fault event, repeating the test with light to confirm the occurrence of the fault event at the same measured fault current, and using the fault current value as a reference for future tests using light on similar devices. (author)

  12. Hydrogen in compound semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Haller, E.E.

    1993-05-01

    Progress in the understanding of hydrogen and its interactions in III/V and II/VI compound semiconductors is reviewed. Donor, acceptor and deep level passivation is well established in III/V compounds based on electrical measurements and on spectroscopic studies. The hydrogen donor levels in GaAs and GaP are estimated to lie near E{sub v}+0.5 eV and E{sub v}+0.3 eV, respectively. Arsenic acceptors have been passivated by hydrogen in CdTe and the very first nitrogen-hydrogen local vibrational model spectra in ZnSe have been reported. This long awaited result may lead to an explanation for the poor activation of nitrogen acceptors in ZnSe grown by techniques which involve high concentrations of hydrogen.

  13. Novel ternary g-C3N4/Ag3VO4/AgBr nanocomposites with excellent visible-light-driven photocatalytic performance for environmental applications

    Science.gov (United States)

    Barzegar, Javid; Habibi-Yangjeh, Aziz; Akhundi, Anise; Vadivel, S.

    2018-04-01

    Novel visible-light-induced photocatalysts were fabricated by integration of Ag3VO4 and AgBr semiconductors with graphitic carbon nitride (g-C3N4) through a facile refluxing method. The fabricated photocatalysts were extensively characterized by XRD, EDX, SEM, TEM, FT-IR, UV-vis DRS, BET, TGA, and PL instruments. The photocatalytic performance of these samples was studied by degradations of three dye contaminants under visible-light exposure. Among the ternary photocatalysts, the g-C3N4/Ag3VO4/AgBr (10%) nanocomposite displayed the maximum activity for RhB degradation with rate constant of 1366.6 × 10-4 min-1, which is 116, 7.23, and 38.5 times as high as those of the g-C3N4, g-C3N4/AgBr (10%), and g-C3N4/Ag3VO4 (30%) photocatalysts, respectively. The effects of synthesis time and calcination temperature were also investigated and discussed. Furthermore, according to the trapping experiments, it was found that superoxide anion radicals were the predominant reactive species in this system. Finally, the ternary photocatalyst displayed superlative activity in removal of the contaminants under visible-light exposure, displaying great potential of this ternary photocatalyst for environmental remediation, because of a facile synthesis route and outstanding photocatalytic performance.

  14. Photocatalytic activity of attapulgite-TiO2-Ag3PO4 ternary nanocomposite for degradation of Rhodamine B under simulated solar irradiation

    Science.gov (United States)

    He, Hongcai; Jiang, Zhuolin; He, Zhaoling; Liu, Tao; Li, Enzhu; Li, Bao-Wen

    2018-01-01

    An excellent ternary composite photocatalyst consisting of silver orthophosphate (Ag3PO4), attapulgite (ATP), and TiO2 was synthesized, in which heterojunction was formed between dissimilar semiconductors to promote the separation of photo-generated charges. The ATP/TiO2/Ag3PO4 composite was characterized by SEM, XRD, and UV-vis diffuse reflectance spectroscopy. The co-deposition of Ag3PO4 and TiO2 nanoparticles onto the surface of ATP forms a lath-particle structure. Compared with composite photocatalysts consisting of two phases, ATP/TiO2/Ag3PO4 ternary composite exhibits greatly improved photocatalytic activity for degradation of rhodamine B under simulated solar irradiation. Such ternary composite not only improves the stability of Ag3PO4, but also lowers the cost by reducing application amount of Ag3PO4, which provides guidance for the design of Ag3PO4- and Ag-based composites for photocatalytic applications.

  15. Completed local ternary pattern for rotation invariant texture classification.

    Science.gov (United States)

    Rassem, Taha H; Khoo, Bee Ee

    2014-01-01

    Despite the fact that the two texture descriptors, the completed modeling of Local Binary Pattern (CLBP) and the Completed Local Binary Count (CLBC), have achieved a remarkable accuracy for invariant rotation texture classification, they inherit some Local Binary Pattern (LBP) drawbacks. The LBP is sensitive to noise, and different patterns of LBP may be classified into the same class that reduces its discriminating property. Although, the Local Ternary Pattern (LTP) is proposed to be more robust to noise than LBP, however, the latter's weakness may appear with the LTP as well as with LBP. In this paper, a novel completed modeling of the Local Ternary Pattern (LTP) operator is proposed to overcome both LBP drawbacks, and an associated completed Local Ternary Pattern (CLTP) scheme is developed for rotation invariant texture classification. The experimental results using four different texture databases show that the proposed CLTP achieved an impressive classification accuracy as compared to the CLBP and CLBC descriptors.

  16. Completed Local Ternary Pattern for Rotation Invariant Texture Classification

    Directory of Open Access Journals (Sweden)

    Taha H. Rassem

    2014-01-01

    Full Text Available Despite the fact that the two texture descriptors, the completed modeling of Local Binary Pattern (CLBP and the Completed Local Binary Count (CLBC, have achieved a remarkable accuracy for invariant rotation texture classification, they inherit some Local Binary Pattern (LBP drawbacks. The LBP is sensitive to noise, and different patterns of LBP may be classified into the same class that reduces its discriminating property. Although, the Local Ternary Pattern (LTP is proposed to be more robust to noise than LBP, however, the latter’s weakness may appear with the LTP as well as with LBP. In this paper, a novel completed modeling of the Local Ternary Pattern (LTP operator is proposed to overcome both LBP drawbacks, and an associated completed Local Ternary Pattern (CLTP scheme is developed for rotation invariant texture classification. The experimental results using four different texture databases show that the proposed CLTP achieved an impressive classification accuracy as compared to the CLBP and CLBC descriptors.

  17. Collective and tracer diffusion kinetics in the ternary random alloy

    International Nuclear Information System (INIS)

    Belova, I.V.; Murch, G.E.; Allnatt, A.R.

    2002-01-01

    In this study, collective and tracer diffusion kinetics is addressed for the ternary random alloy. A formal solution from the self-consistent theory of Moleko et al (Moleko L K, Allnatt A R and Allnatt E L 1989 Phil. Mag. A 59 141) is derived for collective diffusion and compared with the corresponding solution for the binary random alloy. Tracer diffusion in the ternary alloy is treated from the perspective of a special case of the quaternary random alloy. Results from Monte Carlo calculations for tracer and collective correlation factors (for the bcc ternary random alloy) are found to be in excellent agreement with this self-consistent theory but in only semi-quantitative agreement with the earlier theory of Manning (Manning J R 1971 Phys. Rev. B 4 1111). (author)

  18. Constitutional studies of the molybdenum-ruthenium-palladium ternary system

    International Nuclear Information System (INIS)

    Cornish, L.A.; Pratt, J.N.

    1997-01-01

    An experimental and computational study has been made of phase equilibria in the Mo-Ru-Pd ternary system. The constitution of annealed binary and ternary alloys was investigated using optical and electron microscopy, X-ray diffraction and SEM phase analysis techniques. Limited thermodynamic measurements were made using the ZrO 2 solid electrolyte e.m.f. method. The data obtained from the various techniques were used to construct a ternary isothermal section at 1473 K. The experimentally determined section is compared with a calculated section for the same temperature, computed using thermodynamic coefficients derived solely from binary system information. Lattice parameters are reported for the b.c.c., f.c.c. and c.p.h. solid solutions and for the σ phase. (orig.)

  19. Thermal decomposition of cesium-ethylene-ternary graphite intercalation compounds

    International Nuclear Information System (INIS)

    Matsumoto, R.; Oishi, Y.; Arii, T.

    2010-01-01

    In this paper, the thermal decomposition of air-stable Cs-ethylene-ternary graphite intercalation compounds (GICs) is discussed. The air stability of Cs-GICs is improved remarkably after the absorption of ethylene into their interlayer nanospace, because the ethylene molecules oligomerize and block the movement of Cs atoms. In addition, the evaporation of Cs atoms from the Cs-ethylene-ternary GICs is observed above 400 o C under a N 2 atmosphere of 100 Pa by ion attachment mass spectrometry. Although the results indicate that Cs-ethylene-ternary GICs remain stable up to approximately 400 o C, their thermal stability is not very high as compared to that of Cs-GICs.

  20. The partially alternating ternary sum in an associative dialgebra

    International Nuclear Information System (INIS)

    Bremner, Murray R; Sanchez-Ortega, Juana

    2010-01-01

    The alternating ternary sum in an associative algebra, abc - acb - bac + bca + cab - cba, gives rise to the partially alternating ternary sum in an associative dialgebra with products dashv and vdash by making the argument a the center of each term. We use computer algebra to determine the polynomial identities in degree ≤9 satisfied by this new trilinear operation. In degrees 3 and 5, these identities define a new variety of partially alternating ternary algebras. We show that there is a 49-dimensional space of multilinear identities in degree 7, and we find equivalent nonlinear identities. We use the representation theory of the symmetric group to show that there are no new identities in degree 9.

  1. Equilibrium phase diagram of the Ag-Au-Pb ternary system

    International Nuclear Information System (INIS)

    Hassam, S.; Bahari, Z.

    2005-01-01

    The phase diagram of the ternary system Ag-Au-Pb has been established using differential thermal analysis and X-ray powder diffraction analysis. Four vertical sections were studied: X Pb = 0.40, X Au /X Pb = 1/3, X Ag /X Au = 4/1 and X Ag /X Au = 1/1. Two ternary transitory peritectics and one ternary eutectic were characterized. A schematic representation of the ternary equilibria is given

  2. Adiabatic pipelining: a key to ternary computing with quantum dots

    International Nuclear Information System (INIS)

    Pecar, P; Zimic, N; Mraz, M; Lebar Bajec, I; Ramsak, A

    2008-01-01

    The quantum-dot cellular automaton (QCA), a processing platform based on interacting quantum dots, was introduced by Lent in the mid-1990s. What followed was an exhilarating period with the development of the line, the functionally complete set of logic functions, as well as more complex processing structures, however all in the realm of binary logic. Regardless of these achievements, it has to be acknowledged that the use of binary logic is in computing systems mainly the end result of the technological limitations, which the designers had to cope with in the early days of their design. The first advancement of QCAs to multi-valued (ternary) processing was performed by Lebar Bajec et al, with the argument that processing platforms of the future should not disregard the clear advantages of multi-valued logic. Some of the elementary ternary QCAs, necessary for the construction of more complex processing entities, however, lead to a remarkable increase in size when compared to their binary counterparts. This somewhat negates the advantages gained by entering the ternary computing domain. As it turned out, even the binary QCA had its initial hiccups, which have been solved by the introduction of adiabatic switching and the application of adiabatic pipeline approaches. We present here a study that introduces adiabatic switching into the ternary QCA and employs the adiabatic pipeline approach to successfully solve the issues of elementary ternary QCAs. What is more, the ternary QCAs presented here are sizewise comparable to binary QCAs. This in our view might serve towards their faster adoption.

  3. Adiabatic pipelining: a key to ternary computing with quantum dots

    Science.gov (United States)

    Pečar, P.; Ramšak, A.; Zimic, N.; Mraz, M.; Lebar Bajec, I.

    2008-12-01

    The quantum-dot cellular automaton (QCA), a processing platform based on interacting quantum dots, was introduced by Lent in the mid-1990s. What followed was an exhilarating period with the development of the line, the functionally complete set of logic functions, as well as more complex processing structures, however all in the realm of binary logic. Regardless of these achievements, it has to be acknowledged that the use of binary logic is in computing systems mainly the end result of the technological limitations, which the designers had to cope with in the early days of their design. The first advancement of QCAs to multi-valued (ternary) processing was performed by Lebar Bajec et al, with the argument that processing platforms of the future should not disregard the clear advantages of multi-valued logic. Some of the elementary ternary QCAs, necessary for the construction of more complex processing entities, however, lead to a remarkable increase in size when compared to their binary counterparts. This somewhat negates the advantages gained by entering the ternary computing domain. As it turned out, even the binary QCA had its initial hiccups, which have been solved by the introduction of adiabatic switching and the application of adiabatic pipeline approaches. We present here a study that introduces adiabatic switching into the ternary QCA and employs the adiabatic pipeline approach to successfully solve the issues of elementary ternary QCAs. What is more, the ternary QCAs presented here are sizewise comparable to binary QCAs. This in our view might serve towards their faster adoption.

  4. PM1 steganographic algorithm using ternary Hamming Code

    Directory of Open Access Journals (Sweden)

    Kamil Kaczyński

    2015-12-01

    Full Text Available PM1 algorithm is a modification of well-known LSB steganographic algorithm. It has increased resistance to selected steganalytic attacks and increased embedding efficiency. Due to its uniqueness, PM1 algorithm allows us to use of larger alphabet of symbols, making it possible to further increase steganographic capacity. In this paper, we present the modified PM1 algorithm which utilizies so-called syndrome coding and ternary Hamming code. The modified algorithm has increased embedding efficiency, which means fewer changes introduced to carrier and increased capacity.[b]Keywords[/b]: steganography, linear codes, PM1, LSB, ternary Hamming code

  5. The importance of secondary and ternary twinning in compressed Ti

    International Nuclear Information System (INIS)

    Tirry, W.; Nixon, M.; Cazacu, O.; Coghe, F.; Rabet, L.

    2011-01-01

    Twin formation during uniaxial compression of high-purity α-Ti at room temperature is investigated for both quasi-static and dynamic conditions using electron backscatter diffraction techniques. The initial texture is favorable for {101-bar 2} twinning, yet it is observed that secondary and ternary twins occur for both strain rates, showing a higher propensity in the dynamic case. While secondary twins may explain the difference in texture change and strain hardening between the two loading conditions, the ternary twins mainly contribute to grain fractioning.

  6. A novel ternary logic circuit using Josephson junction

    International Nuclear Information System (INIS)

    Morisue, M.; Oochi, K.; Nishizawa, M.

    1989-01-01

    This paper describes a novel Josephson complementary ternary logic circuit named as JCTL. This fundamental circuit is constructed by combination of two SQUIDs, one of which is switched in the positive direction and the other in the negative direction. The JCTL can perform the fundamental operations of AND, OR, NOT and Double NOT in ternary form. The principle of the operation and design criteria are described in detail. The results of the simulation show that the reliable operations of these circuits can be achieved with a high performance

  7. Angular Correlations with γ-RAYS and Neutrons in Ternary Fission of 252Cf

    Science.gov (United States)

    Mutterer, M.; Kopatch, Yu. N.; Singer, P.; Klemens, M.; Hotzel, A.; Schwalm, D.; Thirolf, P.; Hesse, M.; Gönnenwein, F.

    The following sections are included: * Experiment * Data analysis * Anisotropy of γ-Ray Emission in Binary and Ternary Fission * Anisotropy of γ-ray emission with respect to fragment motion * Anisotropy of γ-my emission with respect to a-particle motion * Gamma-ray angular correlations for other ternary fission modes * Neutron Decay of Ternary Particles * References

  8. Binary and ternary carbides and nitrides of the transition metals and their phase relations

    International Nuclear Information System (INIS)

    Holleck, H.

    1981-01-01

    The occurrance and the structure of the binary and ternary transition metal carbides and nitrides are described. Phase diagrams are assessed for most of the binary and ternary systems. Many ternary phase diagrams are published in this report for the first time. (orig.) [de

  9. Semiconductor Nanocrystals for Biological Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Aihua; Gu, Weiwei; Larabell, Carolyn; Alivisatos, A. Paul

    2005-06-28

    Conventional organic fluorophores suffer from poor photo stability, narrow absorption spectra and broad emission feature. Semiconductor nanocrystals, on the other hand, are highly photo-stable with broad absorption spectra and narrow size-tunable emission spectra. Recent advances in the synthesis of these materials have resulted in bright, sensitive, extremely photo-stable and biocompatible semiconductor fluorophores. Commercial availability facilitates their application in a variety of unprecedented biological experiments, including multiplexed cellular imaging, long-term in vitro and in vivo labeling, deep tissue structure mapping and single particle investigation of dynamic cellular processes. Semiconductor nanocrystals are one of the first examples of nanotechnology enabling a new class of biomedical applications.

  10. The ternary system: silicon-uranium-vanadium

    Energy Technology Data Exchange (ETDEWEB)

    Noel, Henri [Laboratoire de Chimie du Solide et Materiaux, UMR-CNRS 6226, Universite de Rennes I, Avenue du General Leclerc, F-35042 Rennes, Cedex (France); Rogl, Peter Franz, E-mail: peter.franz.rogl@univie.ac.a [Institute of Physical Chemistry, University of Vienna, A-1090 Wien, Waehringerstrasse 42 (Austria)

    2010-09-01

    Phase equilibria in the system Si-U-V were established at 1100 {sup o}C by optical microscopy, EMPA and X-ray diffraction. Two ternary compounds were observed, U{sub 2}V{sub 3}Si{sub 4} and (U{sub 1-x}V{sub x}){sub 5}Si{sub 3}, for which the crystal structures were elucidated by X-ray powder data refinement and found to be isotypic with the monoclinic U{sub 2}Mo{sub 3}Si{sub 4}-type (space group P2{sub 1}/c; a = 0.6821(3), b = 0.6820(4), c = 0.6735(3) nm, {beta} = 109.77(1){sup o}) and the tetragonal W{sub 5}Si{sub 3}-type (space group I4/mcm, a = 1.06825(2), c = 0.52764(2) nm), respectively. (U{sub 1-x}V{sub x}){sub 5}Si{sub 3} appears at 1100 {sup o}C without any significant homogeneity region at x {approx} 0.2 resulting in a formula U{sub 4}VSi{sub 3} which corresponds to a fully ordered atom arrangement. DTA experiments clearly show decomposition of this phase above 1206 {sup o}C revealing a two-phase region U{sub 3}Si{sub 2} + V{sub 3}Si. At 1100 {sup o}C U{sub 4}VSi{sub 3} is in equilibrium with V{sub 3}Si, V{sub 5}Si{sub 3}, U{sub 3}Si{sub 2} and U(V). At 800 {sup o}C U{sub 4}VSi{sub 3} forms one vertex of the tie-triangle to U{sub 3}Si and V{sub 3}Si. Due to the rather high thermodynamic stability of V{sub 3}Si and the corresponding tie-lines V{sub 3}Si + liquid at 1100 {sup o}C and V{sub 3}Si + U(V) below 925 {sup o}C, no compatibility exists between U{sub 3}Si or U{sub 3}Si{sub 2} and vanadium metal.

  11. State of the art in semiconductor detectors

    International Nuclear Information System (INIS)

    Rehak, P.; Gatti, E.

    1989-01-01

    The state of the art in semiconductor detectors for elementary particle physics and x-ray astronomy is briefly reviewed. Semiconductor detectors are divided into two groups; classical semiconductor diode detectors; and semiconductor memory detectors. Principles of signal formation for both groups of detectors are described and their performance is compared. New developments of silicon detectors are reported here. 13 refs., 8 figs

  12. Recent Developments in p-Type Oxide Semiconductor Materials and Devices

    KAUST Repository

    Wang, Zhenwei

    2016-02-16

    The development of transparent p-type oxide semiconductors with good performance may be a true enabler for a variety of applications where transparency, power efficiency, and greater circuit complexity are needed. Such applications include transparent electronics, displays, sensors, photovoltaics, memristors, and electrochromics. Hence, here, recent developments in materials and devices based on p-type oxide semiconductors are reviewed, including ternary Cu-bearing oxides, binary copper oxides, tin monoxide, spinel oxides, and nickel oxides. The crystal and electronic structures of these materials are discussed, along with approaches to enhance valence-band dispersion to reduce effective mass and increase mobility. Strategies to reduce interfacial defects, off-state current, and material instability are suggested. Furthermore, it is shown that promising progress has been made in the performance of various types of devices based on p-type oxides. Several innovative approaches exist to fabricate transparent complementary metal oxide semiconductor (CMOS) devices, including novel device fabrication schemes and utilization of surface chemistry effects, resulting in good inverter gains. However, despite recent developments, p-type oxides still lag in performance behind their n-type counterparts, which have entered volume production in the display market. Recent successes along with the hurdles that stand in the way of commercial success of p-type oxide semiconductors are presented.

  13. Selective, electrochemical etching of a semiconductor

    Energy Technology Data Exchange (ETDEWEB)

    Dahal, Rajendra P.; Bhat, Ishwara B.; Chow, Tat-Sing

    2018-03-20

    Methods for facilitating fabricating semiconductor structures are provided which include: providing a multilayer structure including a semiconductor layer, the semiconductor layer including a dopant and having an increased conductivity; selectively increasing, using electrochemical processing, porosity of the semiconductor layer, at least in part, the selectively increasing porosity utilizing the increased conductivity of the semiconductor layer; and removing, at least in part, the semiconductor layer with the selectively increased porosity from the multilayer structure. By way of example, the selectively increasing porosity may include selectively, anodically oxidizing, at least in part, the semiconductor layer of the multilayer structure.

  14. Band gap characterization of ternary BBi1-xNx (0≤x≤1) alloys using modified Becke-Johnson (mBJ) potential

    Science.gov (United States)

    Yalcin, Battal G.

    2015-04-01

    The semi-local Becke-Johnson (BJ) exchange-correlation potential and its modified form proposed by Tran and Blaha have attracted a lot of interest recently because of the surprisingly accurate band gaps they can deliver for many semiconductors and insulators (e.g., sp semiconductors, noble-gas solids, and transition-metal oxides). The structural and electronic properties of ternary alloys BBi1-xNx (0≤x≤1) in zinc-blende phase have been reported in this study. The results of the studied binary compounds (BN and BBi) and ternary alloys BBi1-xNx structures are presented by means of density functional theory. The exchange and correlation effects are taken into account by using the generalized gradient approximation (GGA) functional of Wu and Cohen (WC) which is an improved form of the most popular Perdew-Burke-Ernzerhof (PBE). For electronic properties the modified Becke-Johnson (mBJ) potential, which is more accurate than standard semi-local LDA and PBE calculations, has been chosen. Geometric optimization has been implemented before the volume optimization calculations for all the studied alloys structure. The obtained equilibrium lattice constants of the studied binary compounds are in coincidence with experimental works. And, the variation of the lattice parameter of ternary alloys BBi1-xNx almost perfectly matches with Vegard's law. The spin-orbit interaction (SOI) has been also considered for structural and electronic calculations and the results are compared to those of non-SOI calculations.

  15. Band gap characterization of ternary BBi1−xNx (0≤x≤1) alloys using modified Becke–Johnson (mBJ) potential

    International Nuclear Information System (INIS)

    Yalcin, Battal G.

    2015-01-01

    The semi-local Becke–Johnson (BJ) exchange-correlation potential and its modified form proposed by Tran and Blaha have attracted a lot of interest recently because of the surprisingly accurate band gaps they can deliver for many semiconductors and insulators (e.g., sp semiconductors, noble-gas solids, and transition-metal oxides). The structural and electronic properties of ternary alloys BBi 1−x N x (0≤x≤1) in zinc-blende phase have been reported in this study. The results of the studied binary compounds (BN and BBi) and ternary alloys BBi 1−x N x structures are presented by means of density functional theory. The exchange and correlation effects are taken into account by using the generalized gradient approximation (GGA) functional of Wu and Cohen (WC) which is an improved form of the most popular Perdew–Burke–Ernzerhof (PBE). For electronic properties the modified Becke–Johnson (mBJ) potential, which is more accurate than standard semi-local LDA and PBE calculations, has been chosen. Geometric optimization has been implemented before the volume optimization calculations for all the studied alloys structure. The obtained equilibrium lattice constants of the studied binary compounds are in coincidence with experimental works. And, the variation of the lattice parameter of ternary alloys BBi 1−x N x almost perfectly matches with Vegard's law. The spin–orbit interaction (SOI) has been also considered for structural and electronic calculations and the results are compared to those of non-SOI calculations

  16. Dispersion of nonresonant third-order nonlinearities in GeSiSn ternary alloys.

    Science.gov (United States)

    De Leonardis, Francesco; Troia, Benedetto; Soref, Richard A; Passaro, Vittorio M N

    2016-09-13

    Silicon (Si), tin (Sn), and germanium (Ge) alloys have attracted research attention as direct band gap semiconductors with applications in electronics and optoelectronics. In particular, GeSn field effect transistors can exhibit very high performance in terms of power reduction and operating speed because of the high electron drift mobility, while the SiGeSn system can be constructed using CMOS-compatible techniques to realize lasers, LED, and photodetectors. The wide Si, Ge and Sn transparencies allow the use of binary and ternary alloys extended to mid-IR wavelengths, where nonlinearities can also be employed. However, neither theoretical or experimental predictions of nonlinear features in SiGeSn alloys are reported in the literature. For the first time, a rigorous and detailed physical investigation is presented to estimate the two photon absorption (TPA) coefficient and the Kerr refractive index for the SiGeSn alloy up to 12 μm. The TPA spectrum, the effective TPA wavelength cut-off, and the Kerr nonlinear refractive index have been determined as a function of alloy compositions. The promising results achieved can pave the way to the demonstration of on-chip nonlinear-based applications, including mid-IR spectrometer-on-a-chip, all-optical wavelength down/up-conversion, frequency comb generation, quantum-correlated photon-pair source generation and supercontinuum source creation, as well as Raman lasing.

  17. Light-Triggered Ternary Device and Inverter Based on Heterojunction of van der Waals Materials.

    Science.gov (United States)

    Shim, Jaewoo; Jo, Seo-Hyeon; Kim, Minwoo; Song, Young Jae; Kim, Jeehwan; Park, Jin-Hong

    2017-06-27

    Multivalued logic (MVL) devices/circuits have received considerable attention because the binary logic used in current Si complementary metal-oxide-semiconductor (CMOS) technology cannot handle the predicted information throughputs and energy demands of the future. To realize MVL, the conventional transistor platform needs to be redesigned to have two or more distinctive threshold voltages (V TH s). Here, we report a finding: the photoinduced drain current in graphene/WSe 2 heterojunction transistors unusually decreases with increasing gate voltage under illumination, which we refer to as the light-induced negative differential transconductance (L-NDT) phenomenon. We also prove that such L-NDT phenomenon in specific bias ranges originates from a variable potential barrier at a graphene/WSe 2 junction due to a gate-controllable graphene electrode. This finding allows us to conceive graphene/WSe 2 -based MVL logic circuits by using the I D -V G characteristics with two distinctive V TH s. Based on this finding, we further demonstrate a light-triggered ternary inverter circuit with three stable logical states (ΔV out of each state <0.05 V). Our study offers the pathway to substantialize MVL systems.

  18. Synthesis and Characterization of the Ternary Thiobismuthates A9Bi13S24 (A = K, Rb)

    KAUST Repository

    Davaasuren, Bambar

    2016-11-16

    Ternary alkali metal thiobismuthates ABiS (A = K, Rb) were synthesized by direct combination reactions at 650 °C. The compounds crystallize in the monoclinic space group C2/m (no. 12) with cell parameters a = 30.919(1) Å, b = 4.1008(2) Å, c = 20.9072(9) Å, β = 105.826(3)° for KBiS (1) and a = 31.823(6) Å, b = 4.1177(8) Å, c = 21.086(4) Å, β = 105.62(3)° for RbBiS (2). The crystal structure of 1 contains a 3D [KBiS] polyanionic framework, whereas 2 consists of 2D [RbBiS] polyanionic slabs stacked along [201]. Both 1 and 2 are semiconductors with a band gap of 1.4 and 1.3 eV, respectively, which is supported by an electronic structure calculation. 1 melts congruently at 580 °C, while 2 melts incongruently at 575 °C. 1 and 2 are airstable and insoluble in water and organic solvents.

  19. Semiconductor technology program. Progress briefs

    Science.gov (United States)

    Bullis, W. M.

    1980-01-01

    Measurement technology for semiconductor materials, process control, and devices is reviewed. Activities include: optical linewidth and thermal resistance measurements; device modeling; dopant density profiles; resonance ionization spectroscopy; and deep level measurements. Standardized oxide charge terminology is also described.

  20. Rhombohedrel Hybrid Crystal Semiconductor Device

    Data.gov (United States)

    National Aeronautics and Space Administration — Development of a new high speed and high efficiency hybrid crystal structure semiconductor device based on the the recent invention of rhombohedral hybrid crystal...

  1. Semiconductor radiation detectors. Device physics

    Energy Technology Data Exchange (ETDEWEB)

    Lutz, G. [Max-Planck-Institutes for Physics and Extraterrestrial Physics, Muenchen (Germany). Semiconductor Lab.

    2007-07-01

    Starting from basic principles, the author, whose own contributions to these developments have been significant, describes the rapidly growing field of modern semiconductor detectors used for energy and position measurement radiation. This development was stimulated by requirements in elementary particle physics where it has led to important scientific discoveries. It has now spread to many other fields of science and technology. The book is written in a didactic way and includes an introduction to semiconductor physics. The working principles of semiconductor radiation detectors are explained in an intuitive way, followed by formal quantitative analysis. Broad coverage is also given to electronic signal readout and to the subject of radiation damage. The book is the first to comprehensively cover the semiconductor radiation detectors currently in use. It is useful as a teaching guide and as a reference work for research and applications. (orig.)

  2. Metal-insulator-semiconductor photodetectors.

    Science.gov (United States)

    Lin, Chu-Hsuan; Liu, Chee Wee

    2010-01-01

    The major radiation of the sun can be roughly divided into three regions: ultraviolet, visible, and infrared light. Detection in these three regions is important to human beings. The metal-insulator-semiconductor photodetector, with a simpler process than the pn-junction photodetector and a lower dark current than the MSM photodetector, has been developed for light detection in these three regions. Ideal UV photodetectors with high UV-to-visible rejection ratio could be demonstrated with III-V metal-insulator-semiconductor UV photodetectors. The visible-light detection and near-infrared optical communications have been implemented with Si and Ge metal-insulator-semiconductor photodetectors. For mid- and long-wavelength infrared detection, metal-insulator-semiconductor SiGe/Si quantum dot infrared photodetectors have been developed, and the detection spectrum covers atmospheric transmission windows.

  3. Metal-Insulator-Semiconductor Photodetectors

    Directory of Open Access Journals (Sweden)

    Chu-Hsuan Lin

    2010-09-01

    Full Text Available The major radiation of the Sun can be roughly divided into three regions: ultraviolet, visible, and infrared light. Detection in these three regions is important to human beings. The metal-insulator-semiconductor photodetector, with a simpler process than the pn-junction photodetector and a lower dark current than the MSM photodetector, has been developed for light detection in these three regions. Ideal UV photodetectors with high UV-to-visible rejection ratio could be demonstrated with III-V metal-insulator-semiconductor UV photodetectors. The visible-light detection and near-infrared optical communications have been implemented with Si and Ge metal-insulator-semiconductor photodetectors. For mid- and long-wavelength infrared detection, metal-insulator-semiconductor SiGe/Si quantum dot infrared photodetectors have been developed, and the detection spectrum covers atmospheric transmission windows.

  4. Semiconductor nanocrystals or quantum dots

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 18; Issue 8. Various Quantum Mechanical Concepts for Confinements in Semiconductor Nanocrystals. Jayakrishna Khatei Karuna Kar Nanda. Classroom Volume 18 Issue 8 August 2013 pp 771-776 ...

  5. Atomic layer deposition for semiconductors

    CERN Document Server

    Hwang, Cheol Seong

    2014-01-01

    This edited volume discusses atomic layer deposition (ALD) for all modern semiconductor devices, moving from the basic chemistry of ALD and modeling of ALD processes to sections on ALD for memories, logic devices, and machines.

  6. Quantum optics with semiconductor nanostructures

    CERN Document Server

    Jahnke, Frank

    2012-01-01

    A guide to the theory, application and potential of semiconductor nanostructures in the exploration of quantum optics. It offers an overview of resonance fluorescence emission.$bAn understanding of the interaction between light and matter on a quantum level is of fundamental interest and has many applications in optical technologies. The quantum nature of the interaction has recently attracted great attention for applications of semiconductor nanostructures in quantum information processing. Quantum optics with semiconductor nanostructures is a key guide to the theory, experimental realisation, and future potential of semiconductor nanostructures in the exploration of quantum optics. Part one provides a comprehensive overview of single quantum dot systems, beginning with a look at resonance fluorescence emission. Quantum optics with single quantum dots in photonic crystal and micro cavities are explored in detail, before part two goes on to review nanolasers with quantum dot emitters. Light-matter interaction...

  7. Temperature controller of semiconductor laser

    Czech Academy of Sciences Publication Activity Database

    Matoušek, Vít; Číp, Ondřej

    2003-01-01

    Roč. 73, č. 3 (2003), s. 10 - 12 ISSN 0928-5008 Institutional research plan: CEZ:AV0Z2065902 Keywords : temperature controller * semiconductor laser * laser diode Subject RIV: BH - Optics, Masers, Lasers

  8. Growth Mechanism of Nanowires: Ternary Chalcogenides

    Science.gov (United States)

    Singh, N. B.; Coriell, S. R.; Hopkins, R. H.; Su, Ching Hua; Arnold, B.; Choa, Fow-Sen; Cullum, Brian

    2016-01-01

    In the past two decades there has been a large rise in the investment and expectations for nanotechnology use. Almost every area of research has projected improvements in sensors, or even a promise for the emergence of some novel device technologies. For these applications major focuses of research are in the areas of nanoparticles and graphene. Although there are some near term applications with nanowires in photodetectors and other low light detectors, there are few papers on the growth mechanism and fabrication of nanowire-based devices. Semiconductor nanowires exhibit very favorable and promising optical properties, including high transparency and a several order of magnitude better photocurrent than thin film and bulk materials. We present here an overview of the mechanism of nanowire growth from the melt, and some preliminary results for the thallium arsenic selenide material system. Thallium arsenic selenide (TAS) is a multifunctional material combining excellent acousto-optical, nonlinear and radiation detection properties. We observed that small units of (TAS) nanocubes arrange and rearrange at moderate melt undercooling to form the building block of a nanowire. In some cases very long wires (less than mm) are formed. Since we avoided the catalyst, we observed self-nucleation and uncontrolled growth of wires from different places.

  9. Reducing leakage current in semiconductor devices

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Bin; Matioli, Elison de Nazareth; Palacios, Tomas Apostol

    2018-03-06

    A semiconductor device includes a first region having a first semiconductor material and a second region having a second semiconductor material. The second region is formed over the first region. The semiconductor device also includes a current blocking structure formed in the first region between first and second terminals of the semiconductor device. The current blocking structure is configured to reduce current flow in the first region between the first and second terminals.

  10. Fractal properties of nanostructured semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Zhanabaev, Z.Zh. [Al-Farabi Khazakh National University, Tole bi Street, 96, Almaty 050012 (Kazakhstan); Grevtseva, T.Yu. [Al-Farabi Khazakh National University, Tole bi Street, 96, Almaty 050012 (Kazakhstan)]. E-mail: kenwp@mail.ru

    2007-03-15

    A theory for the temperature and time dependence of current carrier concentration in semiconductors with different non-equilibrium nanocluster structure has been developed. It was shown that the scale-invariant fractal self-similar and self-affine laws can exist near by the transition point to the equilibrium state. Results of the theory have been compared to the experimental data from electrical properties of semiconductor films with nanoclusters.

  11. Wake fields in semiconductor plasmas

    International Nuclear Information System (INIS)

    Berezhiani, V.I.; Mahajan, S.M.

    1994-05-01

    It is shown that an intense short laser pulse propagating through a semiconductor plasma will generated longitudinal Langmuir waves in its wake. The measurable wake field can be used as a diagnostic to study nonlinear optical phenomena. For narrow gap semiconductors (for examples InSb) with Kane-type dispersion relation, the system can simulate, at currently available laser powers, the physics underlying wake-field accelerators. (author). 9 refs, 1 fig

  12. Survey of cryogenic semiconductor devices

    Energy Technology Data Exchange (ETDEWEB)

    Talarico, L.J.; McKeever, J.W.

    1996-04-01

    Improved reliability and electronic performance can be achieved in a system operated at cryogenic temperatures because of the reduction in mechanical insult and in disruptive effects of thermal energy on electronic devices. Continuing discoveries of new superconductors with ever increasing values of T{sub c} above that of liquid nitrogen temperature (LNT) have provided incentive for developing semiconductor electronic systems that may also operate in the superconductor`s liquid nitrogen bath. Because of the interest in high-temperature superconductor (HTS) devices, liquid nitrogen is the cryogen of choice and LNT is the temperature on which this review is focused. The purpose of this survey is to locate and assemble published information comparing the room temperature (298 K), performance of commercially available conventional and hybrid semiconductor device with their performance at LNT (77K), to help establish their candidacy as cryogenic electronic devices specifically for use at LNT. The approach to gathering information for this survey included the following activities. Periodicals and proceedings were searched for information on the behavior of semiconductor devices at LNT. Telephone calls were made to representatives of semiconductor industries, to semiconductor subcontractors, to university faculty members prominent for their research in the area of cryogenic semiconductors, and to representatives of the National Aeronautics and Space Administration (NASA) and NASA subcontractors. The sources and contacts are listed with their responses in the introduction, and a list of references appears at the end of the survey.

  13. Sc-W-Si and Sc-W-Ge ternary systems

    International Nuclear Information System (INIS)

    Kotur, B.Ya.; Voznyak, O.M.; Bodak, O.I.

    1989-01-01

    Phase equilibria in Sc-W-Si and Sc-W-Ge ternary systems are investigated at 1070 K. Sc 2+x W 3-x Si 4 ternary compound (0≤x≤1) is determined, its crystal structure (Ce 2 Sc 3 Si 4 structural type), as well as, change of elementary cell parameters and microhardness within homogeneity range are determined. Regularities of component interaction within Sc-M-Si(Ge) (M-Cr, Mo, W) ternary system are determined. Ternary systems with Mo and W are more closer to each other according to the phase equilibria character, than to ternary systems with Cr

  14. Semiconductor integrated circuits

    International Nuclear Information System (INIS)

    Michel, A.E.; Schwenker, R.O.; Ziegler, J.F.

    1979-01-01

    An improved method involving ion implantation to form non-epitaxial semiconductor integrated circuits. These are made by forming a silicon substrate of one conductivity type with a recessed silicon dioxide region extending into the substrate and enclosing a portion of the silicon substrate. A beam of ions of opposite conductivity type impurity is directed at the substrate at an energy and dosage level sufficient to form a first region of opposite conductivity within the silicon dioxide region. This impurity having a concentration peak below the surface of the substrate forms a region of the one conductivity type which extends from the substrate surface into the first opposite type region to a depth between the concentration peak and the surface and forms a second region of opposite conductivity type. The method, materials and ion beam conditions are detailed. Vertical bipolar integrated circuits can be made this way when the first opposite type conductivity region will function as a collector. Also circuits with inverted bipolar devices when this first region functions as a 'buried'' emitter region. (U.K.)

  15. Amorphous Semiconductor Alloys

    Science.gov (United States)

    Madan, Arun

    1985-08-01

    Amorphous silicon (a-Si) based alloys have attracted a considerable amount of interest because of their applications in a wide variety of technologies. However, the major effort has concentrated on inexpensive photovoltaic device applications and has moved from a laboratory curiosity in the early 1970's to viable commercial applications in the 1980's. Impressive progress in this field has been made since the group at University of Dundee demonstrated that a low defect, device quality hydrogenated amorphous silicon (a-Si:H) 12 material could be produced using the radio frequency (r.f.) glow discharge in SiH4 gas ' and that the material could be doped n- and p-type.3 These results spurred a worldwide interest in a-Si based alloys, especially for photovoltaic devices which has resulted in a conversion efficiency approaching 12%. There is now a quest for even higher conversion efficiencies by using the multijunction cell approach. This necessitates the synthesis of new materials of differing bandgaps, which in principle amorphous semiconductors can achieve. In this article, we review some of this work and consider from a device and a materials point of view the hurdles which have to be overcome before this type of concept can be realized.

  16. Semiconductor film Cherenkov lasers

    Science.gov (United States)

    Walsh, John E.

    1994-12-01

    The technical achievements for the project 'Semiconductor Film Cherenkov Lasers' are summarized. Described in the fourteen appendices are the operation of a sapphire Cherenkov laser and various grating-coupled oscillators. These coherent radiation sources were operated over the spectral range extending from 3 mm down to 400 micrometers. The utility of various types of open, multi-grating resonators and mode-locked operation were also demonstrated. In addition to these experiments, which were carried out with a 10-100 kV pulse generator, a low-energy (3-3.6 MeV) Van de Graaff generator and a low-energy RF linac (2.8 MeV) were used to investigate the properties of continuum incoherent Smith-Purcell radiation. It was shown that levels of intensity comparable to the infrared beam lines on a synchrotron could be obtained and thus that grating-coupled sources are potentially an important new source for Fourier transform spectroscopy. Finally, a scanning electron microscope was adapted for investigating mu-electron-beam-driven far-infrared sources. At the close of the project, spontaneous emission over the 288-800 micrometers band had been observed. Intensity levels were in accord with expectations based on theory. One or more of the Appendices address these topics in detail.

  17. Viscometric and thermodynamic studies of interactions in ternary ...

    Indian Academy of Sciences (India)

    Unknown

    making and structure-breaking capacities of alkali metal halides in pure aqueous solutions and in the pre- sence of sucrose have been ascertained from temperature dependence of φv. 0. Keywords. Ternary solutions; interactions of ionic and nonionic solutes; partial molar volumes; sucrose- alkali metal halide solutions. 1.

  18. Densities and Excess Molar Volume for the Ternary Systems (1 ...

    African Journals Online (AJOL)

    NICO

    2012-09-10

    methylimidazolium methyl sulphate. ([BMIM]+[MeSO4]–) were determined. The ternary systems studied were ([BMIM]+[MeSO4]– + nitromethane + methanol or ethanol or 1-propanol) at the temperatures (303.15 and 313.15) K. The ...

  19. Speeds of sound and isothermal compressibility of ternary liquid ...

    Indian Academy of Sciences (India)

    ternary liquid systems. PACS Nos 43.35.Bf; 61.20.Gy; 82.60.Lf. 1. Introduction. The primary objective is to measure the speeds of sound and density of liquid systems in order to estimate the value of isentropic compressibility (βS). This cannot be done by any other method. Isentropic compressibility has been widely used to ...

  20. Mechanochemically prepared ternary hybrid cathode material for lithium batteries

    International Nuclear Information System (INIS)

    Posudievsky, Oleg Yu; Kozarenko, Olga A.; Dyadyun, Vyacheslav S.; Jorgensen, Scott W.; Spearot, James A.; Koshechko, Vyacheslav G.; Pokhodenko, Vitaly D.

    2013-01-01

    Graphical abstract: The presence of macromolecules of an ion-conducting polymer in the composition of the ternary nanocomposite PPy–PEO/V 2 O 5 promotes interfacial transfer of lithium ions and also facilitates faster transport inside the particles of the nanocomposite. -- Highlights: • Two- and three component nanocomposites are prepared via a solvent-free mechanochemical synthesis. • The nanocomposites retain their capacity above 200 mA h g −1 for at least one hundred cycles. • The presence of PEO promotes interfacial transfer of lithium ions and facilitates faster transport inside the nanocomposite. -- Abstract: Ternary host–guest nanocomposite based on vanadium oxide and two polymers with different types of conductivity (ionic and electronic) – polypyrrole (PPy) and polyethylene oxide (PEO) – is prepared by solventless mechanochemical synthesis. The nanocomposite can be reversibly cycled with a specific capacity of ∼200 mA h g −1 for at least one hundred cycles of full charge–discharge as the active component of the positive electrode of lithium batteries. Electrochemical performance of ternary PPy 0.1 PEO 0.15 V 2 O 5 is compared with two-component analog PPy 0.1 V 2 O 5 . The presence of macromolecules of an ion-conducting polymer in the composition of the ternary nanocomposite PPy 0.1 PEO 0.15 V 2 O 5 promotes interfacial transfer of lithium ions and also facilitates faster transport inside the particles of the nanocomposite

  1. The ternary-encoded fuzzy-neural networks

    OpenAIRE

    Semenova, Olena; Semenov, Andriy; Koval, Kostyantyn; Galka, Andriy

    2012-01-01

    When combining fuzzy logic and neural networks it is possible to get a hybrid system that can process uncertain values and can be trained. Fuzzy logic elements can be regarded as fuzzy-neural networks. In order to present a set of fuzzy values the ternary encoding is used.

  2. Excess isentropic compressibility and speed of sound of the ternary ...

    Indian Academy of Sciences (India)

    Speed of sound of the binary mixtures and the ternary mixture have been compared with calculated values from free length theory (FLT), collision factor theory (CFT), Nomoto's relation (NR), Van Deal's ideal mixing relation (IMR) and Junjie's relation (JR). The results are used to compare the relative merits of these theories ...

  3. Studies on Molecular Interaction in Ternary Liquid Mixtures

    Directory of Open Access Journals (Sweden)

    R. Uvarani

    2010-01-01

    Full Text Available Ultrasonic velocity, density and viscosity for the ternary liquid mixtures of cyclohexanone with 1-propanol and 1-butanol in carbon tetrachloride were measured at 303 K. The acoustical parameters and their excess values were calculated. The trends in the variation of these excess parameters were used to discuss the nature and strength of the interactions present between the component molecules.

  4. Optical Properties of Lead Silver Sulphide Ternary Thin Films ...

    African Journals Online (AJOL)

    Optical Properties of Lead Silver Sulphide Ternary Thin Films Deposited by Chemical Bath Method. ... The optical properties studied include reflectance, absorption coefficient, thickness, refractive index, extinction coefficient, optical conductivity and band gap energy. The films showed very high absorbance in the UV region, ...

  5. Application of Analytic Geometry to Ternary and Quaternary Diagrams.

    Science.gov (United States)

    MacCarthy, Patrick

    1986-01-01

    Advantages of representing ternary and quaternary composition diagrams by means of rectangular coordinates were pointed out in a previous paper (EJ 288 693). A further advantage of that approach is that analytic geometry, based on rectangular coordinates, is directly applicable as demonstrated by the examples presented. (JN)

  6. Ternary forecast of heavy snowfall in the Honam area, Korea

    Science.gov (United States)

    Sohn, Keon Tae; Lee, Jeong Hyeong; Cho, Young Seuk

    2009-03-01

    The objective of this study is to improve the statistical modeling for the ternary forecast of heavy snowfall in the Honam area in Korea. The ternary forecast of heavy snowfall consists of one of three values, 0 for less than 50 mm, 1 for an advisory (50-150 mm), and 2 for a warning (more than 150 mm). For our study, the observed daily snow amounts and the numerical model outputs for 45 synoptic factors at 17 stations in the Honam area during 5 years (2001 to 2005) are used as observations and potential predictors respectively. For statistical modeling and validation, the data set is divided into training data and validation data by cluster analysis. A multi-grade logistic regression model and neural networks are separately applied to generate the probabilities of three categories based on the model output statistic (MOS) method. Two models are estimated by the training data and tested by the validation data. Based on the estimated probabilities, three thresholds are chosen to generate ternary forecasts. The results are summarized in 3×3 contingency tables and the results of the three-grade logistic regression model are compared to those of the neural networks model. According to the model training and model validation results, the estimated three-grade logistic regression model is recommended as a ternary forecast model for heavy snowfall in the Honam area.

  7. Robust Self-Triggered Coordination With Ternary Controllers

    NARCIS (Netherlands)

    De Persis, Claudio; Frasca, Paolo; Nair, G.N.

    2013-01-01

    This paper regards the coordination of networked systems, studied in the framework of hybrid dynamical systems. We design a coordination scheme which combines the use of ternary controllers with a self-triggered communication policy. The communication policy requires the agents to measure, at each

  8. Excess isentropic compressibility and speed of sound of the ternary

    Indian Academy of Sciences (India)

    These excess properties of the binary mixtures were fitted to Redlich-Kister equation, while the Cibulka's equation was used to fit the values related to the values to the ternary system. These excess properties have been used to discuss the presence of significant interactions between the component molecules in the binary ...

  9. Univolatility curves in ternary mixtures: geometry and numerical computation

    DEFF Research Database (Denmark)

    Shcherbakova, Nataliya; Rodriguez-Donis, Ivonne; Abildskov, Jens

    2017-01-01

    We propose a new non-iterative numerical algorithm allowing computation of all univolatility curves in homogeneous ternary mixtures independently of the presence of the azeotropes. The key point is the concept of generalized univolatility curves in the 3D state space, which allows the main...... computational part to be reduced to a simple integration of a system of ordinary differential equations....

  10. Segregation in ternary alloys: an interplay of driving forces

    International Nuclear Information System (INIS)

    Luyten, J.; Helfensteyn, S.; Creemers, C.

    2003-01-01

    Monte Carlo (MC) simulations combined with the constant bond energy (CBE) model are set up to explore and understand the general segregation behaviour in ternary alloys as a function of composition and more in particular the segregation to Cu-Ni-Al (1 0 0) surfaces. Besides its simplicity, allowing swift simulations, which are necessary for a first general survey over all possible compositions, one of the advantages of the CBE model lies in the possibility to clearly identify the different driving forces for segregation. All simulations are performed in the Grand Canonical Ensemble, using a new algorithm to determine the chemical potential of the components. Notwithstanding the simplicity of the CBE model, one extra feature is evidenced: depending on the values of the interatomic interaction parameters, in some regions of the ternary diagram, a single solid solution becomes thermodynamically unstable, leading to demixing into two conjugate phases. The simulations are first done for three hypothetical systems that are however representative for real alloy systems. The three systems are characterised by different sets of interatomic interaction parameters. These extensive simulations over the entire composition range of the ternary alloy yield a 'topographical' segregation map, showing distinct regions where different species segregate. These distinct domains originate from a variable interplay between the driving forces for segregation and attractive/repulsive interactions in the bulk of the alloy. The results on these hypothetical systems are very helpful for a better understanding of the segregation behaviour in Cu-Ni-Al and other ternary alloys

  11. Robust self-triggered coordination with ternary controllers

    NARCIS (Netherlands)

    De Persis, Claudio; Frasca, Paolo

    2013-01-01

    This paper regards the coordination of networked systems, studied in the framework of hybrid dynamical systems. We design a coordination scheme which combines the use of ternary controllers with a self-triggered communication policy. The communication policy requires the agents to measure, at each

  12. Intermolecular Interactions in Ternary Glycerol–Sample–H2O

    DEFF Research Database (Denmark)

    Westh, Peter; Rasmussen, Erik Lumby; Koga, Yoshikata

    2011-01-01

    We studied the intermolecular interactions in ternary glycerol (Gly)–sample (S)–H2O systems at 25 °C. By measuring the excess partial molar enthalpy of Gly, HGlyEHEGly, we evaluated the Gly–Gly enthalpic interaction, HGly-GlyEHEGly--Gly, in the presence of various samples (S). For S, tert...

  13. Ternary mixtures of alkyltriphenylphosphonium bromides (C12 TPB ...

    Indian Academy of Sciences (India)

    Administrator

    TPB) in aqueous medium: their interfacial, bulk and fluorescence quenching behaviour. GARGI BASU RAY, SOUMEN .... aqueous and micellar media of CTAB and SDS at concentrations 20 times their CMCs. The alkyl- ... vailing in the ternary mixed micelles in contrast to the predominantly antagonistic behaviour reported.

  14. Ternary mixtures of alkyltriphenylphosphonium bromides (C12 TPB ...

    Indian Academy of Sciences (India)

    Administrator

    C14TPB and C16TPB, respectively (structures shown in scheme 1). Prasad et al23 have reported the prop- erties of binary .... dicating associative or cooperative interaction pre- vailing in the ternary mixed micelles in contrast to ... The organizational change in the mixed systems with variation in the associated counterion.

  15. Evaluation of griseofulvin binary and ternary solid dispersions with HPMCAS.

    Science.gov (United States)

    Al-Obaidi, Hisham; Buckton, Graham

    2009-01-01

    The stability and dissolution properties of griseofulvin binary and ternary solid dispersions were evaluated. Solid dispersions of griseofulvin and hydroxypropyl methylcellulose acetate succinate (HPMCAS) were prepared using the spray drying method. A third polymer, poly[N-(2-hydroxypropyl)methacrylate] (PHPMA), was incorporated to investigate its effect on the interaction of griseofulvin with HPMCAS. In this case, HPMCAS can form H bonds with griseofulvin directly; the addition of PHPMA to the solid dispersion may enhance the stability of the amorphous griseofulvin due to greater interaction with griseofulvin. The X-ray powder diffraction results showed that griseofulvin (binary and ternary solid dispersions) remained amorphous for more than 19 months stored at 85% RH compared with the spray-dried griseofulvin which crystallized totally within 24 h at ambient conditions. The Fourier transform infrared scan showed that griseofulvin carbonyl group formed hydrogen bonds with the hydroxyl group in the HPMCAS, which could explain the extended stability of the drug. Further broadening in the peak could be seen when PHPMA was added to the solid dispersion, which indicates stronger interaction. The glass transition temperatures increased in the ternary solid dispersions regardless of HPMCAS grade. The dissolution rate of the drug in the solid dispersion (both binary and ternary) has significantly increased when compared with the dissolution profile of the spray-dried griseofulvin. These results reveal significant stability of the amorphous form due to the hydrogen bond formation with the polymer. The addition of the third polymer improved the stability but had a minor impact on dissolution.

  16. EDITORIAL: Oxide semiconductors

    Science.gov (United States)

    Kawasaki, M.; Makino, T.

    2005-04-01

    Blue or ultraviolet semiconducting light-emitting diodes have the potential to revolutionize illumination systems in the near-future. Such industrial need has propelled the investigation of several wide-gap semiconducting materials in recent years. Commercial applications include blue lasers for DVD memory and laser printers, while military applications are also expected. Most of the material development has so far been focused on GaN (band gap 3.5 eV at 2 K), and ZnSe (2.9 eV) because these two representative direct transition semiconductors are known to be bright emitting sources. GaN and GaN-based alloys are emerging as the winners in this field because ZnSe is subject to defect formation under high current drive. On the other hand, another II-VI compound, ZnO, has also excited substantial interest in the optoelectronics-oriented research communities because it is the brightest emitter of all, owing to the fact that its excitons have a 60 meV binding energy. This is compared with 26 meV for GaN and 20 meV for ZnSe. The stable excitons could lead to laser action based on their recombination even at temperatures well above room temperature. ZnO has additional major properties that are more advantageous than other wide-gap materials: availability of large area substrates, higher energy radiation stability, environmentally-friendly ingredients, and amenability to wet chemical etching. However, ZnO is not new to the semiconductor field as exemplified by several studies made during the 1960s on structural, vibrational, optical and electrical properties (Mollwo E 1982 Landolt-Boernstein New Series vol 17 (Berlin: Springer) p 35). In terms of devices, the luminescence from light-emitting diode structures was demonstrated in which Cu2O was used as the p-type material (Drapak I T 1968 Semiconductors 2 624). The main obstacle to the development of ZnO has been the lack of reproducible p-type ZnO. The possibility of achieving epitaxial p-type layers with the aid of thermal

  17. First-principles study of ternary Li-Al-Te compounds under high pressure

    Science.gov (United States)

    Wang, Youchun; Tian, Fubo; Li, Da; Duan, Defang; Xie, Hui; Liu, Bingbing; Zhou, Qiang; Cui, Tian

    2018-02-01

    The ternary Li-Al-Te compounds were investigated by the first-principle evolutionary calculation based on density function theory. Apart from the known structure, I-42d LiAlTe2 and P3m1 LiAlTe2, several new structures were discovered, P-3m1 LiAlTe2, Pnma LiAlTe2, C2/c Li9AlTe2, Immm Li9AlTe2 and P4/mmm Li6AlTe. We determined that the I-42d LiAlTe2 firstly changed to P-3m1 phase at 6 GPa, and then into the Pnma structure at 65 GPa, Pnma phase was stable up at least to 120 GPa. I-42d LiAlTe2 was a pseudo-direct band gap semiconductor, but P-3m1 LiAlT2 was an indirect band gap semiconductor. This may be caused by the pressure effect. Subsequently, it was metallized under pressure. Pnma LiAlTe2 was also metallic at the pressure we studied. C2/c Li9AlTe2 was stable above 4 GPa, then turned into Immm phase at 60 GPa. C2/c Li9AlTe2 was an indirect band gap semiconductor. The results show that P4/mmm Li6AlTe was stable and metallized in the pressure range of 0.7-120 GPa. The calculations of DOS and PDOS indicate that the arrangement of electrons near Fermi energy can be affected by the increase of Li. The calculated ELF results and Bader charge analysis indicate that there was no covalent bond between Al and Te atoms for high-pressure Pnma LiAlTe2, Li9AlTe2 and Li6AlTe. For Li9AlTe2 and Li6AlTe, different from LiAlTe2, Al atoms not connect with Te atoms, but link with Li atoms. The results were further proved by Mulliken population analysis. And the weak covalent bonds between Li and Al atoms stem from the hybridization of Li s and Al p presented in PDOS diagrams. We further deduced that the pressure effect and the increase of Li content may result in the disappearance of Al-Te bonds for Li-Al-Te compound under extreme pressure.

  18. First and second harmonic generation of the XAl{sub 2}Se{sub 4} (X=Zn,Cd,Hg) defect chalcopyrite compounds

    Energy Technology Data Exchange (ETDEWEB)

    Ouahrani, Tarik, E-mail: tarik_ouahrani@yahoo.fr [Laboratoire de Physique Theorique, Universite de Tlemcen, B.P.230,13000 Tlemcen (Algeria); Ecole Preparatoire en Sciences et Techniques, Depertement de Physique EPST-T, Tlemcen 13000 (Algeria); Khenata, R. [Laboratoire de Physique Quantique et de Modelisation Mathematique (LPQ3M), Universite de Mascara, 29000 Mascara (Algeria); Lasri, B. [Laboratoire de Physique Theorique, Universite de Tlemcen, B.P.230,13000 Tlemcen (Algeria); Universite Dr Tahar Moulay de Saida, B.P. 138, Cite el Nasr, Saida 20000 (Algeria); Reshak, Ali H. [School of Complex systems, FFPW- South Bohemia University, Nove Hrady 37333 (Czech Republic); School of Material Engineering, Malaysia University of Perlis, P.O Box 77, d/a Pejabat Pos Besar, 01007 Kangar, Perlis (Malaysia); Bouhemadou, A. [Department of Physics, Faculty of Sciences, University of Setif, 19000 Setif (Algeria); Bin-Omran, S. [Department of Physics and Astronomy, Faculty of Science, King Saud University, P.O. Box 2455, Riyadh 11451 (Saudi Arabia)

    2012-09-15

    The chemical bonding of the ZnAl{sub 2}Se{sub 4}, CdAl{sub 2}Se{sub 4} and HgAl{sub 2}Se{sub 4} defect chalcopyrites has been studied in the framework of the quantum theory of atoms in molecules (AIM). The GW quasi-particle approximation is used to correct the DFT-underestimation of energy gap, and as a consequence the linear and nonlinear optical properties are significantly enhanced. The second harmonic generation (SHG) displays certain dependence with the ionicity degree decrease through the dependency of the SHG on the band gap. The occurrence of the AIM saddle point is characterized and some clarifying features in relationship with the density topology are exposed, which enable to understand the relation with the second harmonic generation effect.

  19. Experimental investigation of the Ag–Bi–I ternary system and thermodynamic properties of the ternary phases

    International Nuclear Information System (INIS)

    Mashadieva, Leyla F.; Aliev, Ziya S.; Shevelkov, Andrei V.; Babanly, Mahammad B.

    2013-01-01

    Highlights: ► The self-consistent phase diagram of the Ag–Bi–I system is constructed. ► Ag 2 BiI 5 and AgBi 2 I 7 are the only ternary phases of the system. ► Standard thermodynamic functions of formation and the standard entropies of Ag 2 BiI 5 and AgBi 2 I 7 are calculated. - Abstract: The phase equilibriums in the Ag–Bi–I ternary system and thermodynamic properties of the ternary phases were experimentally determined by using DTA and XRD techniques and EMF measurements with the Ag 4 RbI 5 solid electrolyte. According to the obtained experimental results, the polythermal sections of the ternary phase diagram, its isothermal section at 300 K as well as the projection of the liquids surface have been revised. The fields of the primary crystallization and types and coordinates of nonvariant and monovariant equilibriums were determined. The partial molar functions of silver iodide and silver in the alloys as well as the standard thermodynamic functions of formation and the standard entropies of Ag 2 BiI 5 and AgBi 2 I 7 were calculated based on EMF measurements.

  20. Semiconductor lasers stability, instability and chaos

    CERN Document Server

    Ohtsubo, Junji

    2017-01-01

    This book describes the fascinating recent advances made concerning the chaos, stability and instability of semiconductor lasers, and discusses their applications and future prospects in detail. It emphasizes the dynamics in semiconductor lasers by optical and electronic feedback, optical injection, and injection current modulation. Applications of semiconductor laser chaos, control and noise, and semiconductor lasers are also demonstrated. Semiconductor lasers with new structures, such as vertical-cavity surface-emitting lasers and broad-area semiconductor lasers, are intriguing and promising devices. Current topics include fast physical number generation using chaotic semiconductor lasers for secure communication, development of chaos, quantum-dot semiconductor lasers and quantum-cascade semiconductor lasers, and vertical-cavity surface-emitting lasers. This fourth edition has been significantly expanded to reflect the latest developments. The fundamental theory of laser chaos and the chaotic dynamics in se...

  1. Solution-based colloidal synthesis of hybrid P3HT: Ternary CuInSe2 nanocomposites using a novel combination of capping agents for low-cost photovoltaics

    Science.gov (United States)

    Sharma, Shailesh Narain; Chawla, Parul; Akanksha; Srivastava, A. K.

    2016-06-01

    In this work, ternary CuInSe2 (CISe) chalcopyrite nanocrystallites efficiently passivated by a novel combination of capping agents viz: aniline and 1-octadecene during chemical route synthesis were dispersed in conducting polymer matrix poly(3-hexylthiophene) (P3HT). By varying the composition and concentration of the ligands, the properties of the resulting CISe nanocrystallites and its corresponding polymer nanocomposites thus could be tailored. The structural, morphological and optical studies accomplished by various complimentary techniques viz. Transmission Electron Microscopy (TEM), Contact angle, Photoluminescence (PL) and Raman have enabled us to compare the different hybrid organic (polymer)-inorganic nanocomposites. On the basis of aniline-octadecene equilibrium phase diagram, the polydispersity of the CISe nanocrystals could be tuned by using controlled variations in the reaction conditions of nucleation and growth such as composition of the solvent and temperature. To the best of author's knowledge, the beneficial effects of both the capping agents; aniline and octadecene contributing well in tandem in the development of large-sized (100-125 nm) high quality, sterically- and photo-oxidative stable polycrystalline CISe and its corresponding polymer (P3HT):CISe composites with enhanced charge transfer efficiency has been reported for the first time. The low-cost synthesis and ease of preparation renders this method of great potential for its possible application in low-cost hybrid organic-inorganic photovoltaics. The figure shows the Temperature vs Mole fraction graph of two different phases (aniline and 1-octadecene) in equilibrium.

  2. Semiconductor optoelectronic infrared spectroscopy

    International Nuclear Information System (INIS)

    Hollingworth, A.R.

    2001-08-01

    We use spectroscopy to study infrared optoelectronic inter and intraband semiconductor carrier dynamics. The overall aim of this thesis was to study both III-V and Pb chalcogenide material systems in order to show their future potential use in infrared emitters. The effects of bandstructure engineering have been studied in the output characteristics of mid-IR III-V laser diodes to show which processes (defects, radiative, Auger and phonon) dominate and whether non-radiative processes can be suppressed. A new three-beam pump probe experiment was used to investigate interband recombination directly in passive materials. Experiments on PbSe and theory for non-parabolic near-mirror bands and non-degenerate statistics were in good agreement. Comparisons with HgCdTe showed a reduction in the Auger coefficient of 1-2 orders of magnitude in the PbSe. Using Landau confinement to model spatial confinement in quantum dots (QDs) 'phonon bottlenecking' was studied. The results obtained from pump probe and cyclotron resonance saturation measurements showed a clear suppression in the cooling of carriers when Landau level separation was not resonant with LO phonon energy. When a bulk laser diode was placed in a magnetic field to produce a quasi quantum wire device the resulting enhanced differential gain and reduced Auger recombination lowered I th by 30%. This result showed many peaks in the light output which occurred when the LO phonon energy was a multiple of the Landau level separation. This showed for the first time evidence of the phonon bottleneck in a working laser device. A new technique called time resolved optically detected cyclotron resonance, was used as a precursor to finding the carrier dynamics within a spatially confined quantum dot. By moving to the case of a spatial QD using an optically detected intraband resonance it was possible to measure the energy separation interband levels and conduction and valence sublevels within the dot simultaneously. Furthermore

  3. Thiophene-Based Organic Semiconductors.

    Science.gov (United States)

    Turkoglu, Gulsen; Cinar, M Emin; Ozturk, Turan

    2017-10-24

    Thiophene-based π-conjugated organic small molecules and polymers are the research subject of significant current interest owing to their potential use as organic semiconductors in material chemistry. Despite simple and similar molecular structures, the hitherto reported properties of thiophene-based organic semiconductors are rather diverse. Design of high performance organic semiconducting materials requires a thorough understanding of inter- and intra-molecular interactions, solid-state packing, and the influence of both factors on the charge carrier transport. In this chapter, thiophene-based organic semiconductors, which are classified in terms of their chemical structures and their structure-property relationships, are addressed for the potential applications as organic photovoltaics (OPVs), organic field-effect transistors (OFETs) and organic light emitting diodes (OLEDs).

  4. Catalysts, Protection Layers, and Semiconductors

    DEFF Research Database (Denmark)

    Chorkendorff, Ib

    2015-01-01

    Hydrogen is the simplest solar fuel to produce and in this presentation we shall give a short overview of the pros and cons of various tandem devices [1]. The large band gap semiconductor needs to be in front, but apart from that we can chose to have either the anode in front or back using either...... acid or alkaline conditions. Since most relevant semiconductors are very prone to corrosion the advantage of using buried junctions and using protection layers offering shall be discussed [2-4]. Next we shall discuss the availability of various catalysts for being coupled to these protections layers...... and how their stability may be evaluated [5, 6]. Examples of half-cell reaction using protection layers for both cathode and anode will be discussed though some of recent examples under both alkaline and acidic conditions. Si is a very good low band gap semiconductor and by using TiO2 as a protection...

  5. High pressure semiconductor physics I

    CERN Document Server

    Willardson, R K; Paul, William; Suski, Tadeusz

    1998-01-01

    Since its inception in 1966, the series of numbered volumes known as Semiconductors and Semimetals has distinguished itself through the careful selection of well-known authors, editors, and contributors. The "Willardson and Beer" Series, as it is widely known, has succeeded in publishing numerous landmark volumes and chapters. Not only did many of these volumes make an impact at the time of their publication, but they continue to be well-cited years after their original release. Recently, Professor Eicke R. Weber of the University of California at Berkeley joined as a co-editor of the series. Professor Weber, a well-known expert in the field of semiconductor materials, will further contribute to continuing the series' tradition of publishing timely, highly relevant, and long-impacting volumes. Some of the recent volumes, such as Hydrogen in Semiconductors, Imperfections in III/V Materials, Epitaxial Microstructures, High-Speed Heterostructure Devices, Oxygen in Silicon, and others promise indeed that this tra...

  6. Selenium semiconductor core optical fibers

    Directory of Open Access Journals (Sweden)

    G. W. Tang

    2015-02-01

    Full Text Available Phosphate glass-clad optical fibers containing selenium (Se semiconductor core were fabricated using a molten core method. The cores were found to be amorphous as evidenced by X-ray diffraction and corroborated by Micro-Raman spectrum. Elemental analysis across the core/clad interface suggests that there is some diffusion of about 3 wt % oxygen in the core region. Phosphate glass-clad crystalline selenium core optical fibers were obtained by a postdrawing annealing process. A two-cm-long crystalline selenium semiconductor core optical fibers, electrically contacted to external circuitry through the fiber end facets, exhibit a three times change in conductivity between dark and illuminated states. Such crystalline selenium semiconductor core optical fibers have promising utility in optical switch and photoconductivity of optical fiber array.

  7. Size effect caused significant reduction of thermal conductivity of GaAs/AlAs distributed Bragg reflector used in semiconductor disk laser

    Science.gov (United States)

    Zhang, Peng; Zhu, Renjiang; Jiang, Maohua; Song, Yanrong; Zhang, Dingke; Cui, Yuting

    2017-11-01

    Thermal properties of the distributed Bragg reflector (DBR) used in the semiconductor gain element are crucial for the performance of a semiconductor disk laser (SDL). For the purpose of more reasonable semiconductor wafer design, so as to improve the thermal management of SDLs, accurate thermal conductivity value of a DBR is under considerable requirement. By the use of equilibrium molecular dynamics method, thermal conductivities of GaAs/AlAs DBRs, which are widely employed in 1 μm waveband SDLs, are calculated, and simulated results are compared with the reported experimental data. Influences of the layer thickness on the thermal conductivities of the DBR structure and the effects of Al composition on the AlxGa1-xAs ternary alloy values are focused and analyzed.

  8. Semiconductor X-ray spectrometers

    International Nuclear Information System (INIS)

    Muggleton, A.H.F.

    1978-02-01

    An outline is given of recent developments in particle and photon induced x-ray fluorescence (XRF) analysis. Following a brief description of the basic mechanism of semiconductor detector operation a comparison is made between semiconductor detectors, scintillators and gas filled proportional devices. Detector fabrication and cryostat design are described in more detail and the effects of various device parameters on system performance, such as energy resolution, count rate capability, efficiency, microphony, etc. are discussed. The main applications of these detectors in x-ray fluorescence analysis, electron microprobe analysis, medical and pollution studies are reviewed

  9. Modeling of semiconductor optical amplifiers

    DEFF Research Database (Denmark)

    Mørk, Jesper; Bischoff, Svend; Berg, Tommy Winther

    We discuss the modelling of semiconductor optical amplifiers with emphasis on their high-speed properties. Applications in linear amplification as well as ultrafast optical signal processing are reviewed. Finally, the possible role of quantum-dot based optical amplifiers is discussed.......We discuss the modelling of semiconductor optical amplifiers with emphasis on their high-speed properties. Applications in linear amplification as well as ultrafast optical signal processing are reviewed. Finally, the possible role of quantum-dot based optical amplifiers is discussed....

  10. Semiconductors and semimetals epitaxial microstructures

    CERN Document Server

    Willardson, Robert K; Beer, Albert C; Gossard, Arthur C

    1994-01-01

    Newly developed semiconductor microstructures can now guide light and electrons resulting in important consequences for state-of-the-art electronic and photonic devices. This volume introduces a new generation of epitaxial microstructures. Special emphasis has been given to atomic control during growth and the interrelationship between the atomic arrangements and the properties of the structures.Key Features* Atomic-level control of semiconductor microstructures* Molecular beam epitaxy, metal-organic chemical vapor deposition* Quantum wells and quantum wires* Lasers, photon(IR)detectors, heterostructure transistors

  11. Semiconductor lasers and herterojunction leds

    CERN Document Server

    Kressel, Henry

    2012-01-01

    Semiconductor Lasers and Heterojunction LEDs presents an introduction to the subject of semiconductor lasers and heterojunction LEDs. The book reviews relevant basic solid-state and electromagnetic principles; the relevant concepts in solid state physics; and the p-n junctions and heterojunctions. The text also describes stimulated emission and gain; the relevant concepts in electromagnetic field theory; and the modes in laser structures. The relation between electrical and optical properties of laser diodes; epitaxial technology; binary III-V compounds; and diode fabrication are also consider

  12. Semiconductor device physics and simulation

    CERN Document Server

    Yuan, J S

    1998-01-01

    This volume provides thorough coverage of modern semiconductor devices -including hetero- and homo-junction devices-using a two-dimensional simulator (MEDICI) to perform the analysis and generate simulation results Each device is examined in terms of dc, ac, and transient simulator results; relevant device physics; and implications for design and analysis Two hundred forty-four useful figures illustrate the physical mechanisms and characteristics of the devices simulated Comprehensive and carefully organized, Semiconductor Device Physics and Simulation is the ideal bridge from device physics to practical device design

  13. Introduction to semiconductor manufacturing technology

    CERN Document Server

    2012-01-01

    IC chip manufacturing processes, such as photolithography, etch, CVD, PVD, CMP, ion implantation, RTP, inspection, and metrology, are complex methods that draw upon many disciplines. [i]Introduction to Semiconductor Manufacturing Technologies, Second Edition[/i] thoroughly describes the complicated processes with minimal mathematics, chemistry, and physics; it covers advanced concepts while keeping the contents accessible to readers without advanced degrees. Designed as a textbook for college students, this book provides a realistic picture of the semiconductor industry and an in-depth discuss

  14. Wide band gap semiconductor templates

    Energy Technology Data Exchange (ETDEWEB)

    Arendt, Paul N. (Los Alamos, NM); Stan, Liliana (Los Alamos, NM); Jia, Quanxi (Los Alamos, NM); DePaula, Raymond F. (Santa Fe, NM); Usov, Igor O. (Los Alamos, NM)

    2010-12-14

    The present invention relates to a thin film structure based on an epitaxial (111)-oriented rare earth-Group IVB oxide on the cubic (001) MgO terminated surface and the ion-beam-assisted deposition ("IBAD") techniques that are amendable to be over coated by semiconductors with hexagonal crystal structures. The IBAD magnesium oxide ("MgO") technology, in conjunction with certain template materials, is used to fabricate the desired thin film array. Similarly, IBAD MgO with appropriate template layers can be used for semiconductors with cubic type crystal structures.

  15. Organic semiconductors in sensor applications

    CERN Document Server

    Malliaras, George; Owens, Róisín

    2008-01-01

    Organic semiconductors offer unique characteristics such as tunability of electronic properties via chemical synthesis, compatibility with mechanically flexible substrates, low-cost manufacturing, and facile integration with chemical and biological functionalities. These characteristics have prompted the application of organic semiconductors and their devices in physical, chemical, and biological sensors. This book covers this rapidly emerging field by discussing both optical and electrical sensor concepts. Novel transducers based on organic light-emitting diodes and organic thin-film transistors, as well as systems-on-a-chip architectures are presented. Functionalization techniques to enhance specificity are outlined, and models for the sensor response are described.

  16. Semiconductor structure and recess formation etch technique

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Bin; Sun, Min; Palacios, Tomas Apostol

    2017-02-14

    A semiconductor structure has a first layer that includes a first semiconductor material and a second layer that includes a second semiconductor material. The first semiconductor material is selectively etchable over the second semiconductor material using a first etching process. The first layer is disposed over the second layer. A recess is disposed at least in the first layer. Also described is a method of forming a semiconductor structure that includes a recess. The method includes etching a region in a first layer using a first etching process. The first layer includes a first semiconductor material. The first etching process stops at a second layer beneath the first layer. The second layer includes a second semiconductor material.

  17. Waveguide based external cavity semiconductor lasers

    NARCIS (Netherlands)

    Oldenbeuving, Ruud; Klein, E.J.; Offerhaus, Herman L.; Lee, Christopher James; Verhaegen, M.; Boller, Klaus J.

    2012-01-01

    We report on progress of the project waveguide based external cavity semiconductor laser (WECSL) arrays. Here we present the latest results on our efforts to mode lock an array of tunable, external cavity semiconductor lasers.

  18. Fundamentals of semiconductors physics and materials properties

    CERN Document Server

    Yu, Peter Y

    2005-01-01

    Provides detailed explanations of the electronic, vibrational, transport, and optical properties of semiconductors. This textbook emphasizes understanding the physical properties of Si and similar tetrahedrally coordinated semiconductors and features an extensive collection of tables of material parameters, figures, and problems.

  19. Influence of phonons on semiconductor quantum emission

    Energy Technology Data Exchange (ETDEWEB)

    Feldtmann, Thomas

    2009-07-06

    A microscopic theory of interacting charge carriers, lattice vibrations, and light modes in semiconductor systems is presented. The theory is applied to study quantum dots and phonon-assisted luminescence in bulk semiconductors and heterostructures. (orig.)

  20. Thermodynamic calculations in ternary titanium–aluminium–manganese system

    Directory of Open Access Journals (Sweden)

    ANA I. KOSTOV

    2008-04-01

    Full Text Available Thermodynamic calculations in the ternary Ti–Al–Mn system are shown in this paper. The thermodynamic calculations were performed using the FactSage thermochemical software and database, with the aim of determining thermodynamic properties, such as activities, coefficient of activities, partial and integral values of the enthalpies and Gibbs energies of mixing and excess energies at two different temperatures: 2000 and 2100 K. Bearing in mind that no experimental data for the Ti–Al–Mn ternary system have been obtained or reported. The obtained results represent a good base for further thermodynamic analysis and may be useful as a comparison with some future critical experimental results and thermodynamic optimization of this system.

  1. A New Multifunctional Sensor for Measuring Concentrations of Ternary Solution

    Science.gov (United States)

    Wei, Guo; Shida, Katsunori

    This paper presents a multifunctional sensor with novel structure, which is capable of directly sensing temperature and two physical parameters of solutions, namely ultrasonic velocity and conductivity. By combined measurement of these three measurable parameters, the concentrations of various components in a ternary solution can be simultaneously determined. The structure and operation principle of the sensor are described, and a regression algorithm based on natural cubic spline interpolation and the least square method is adopted to estimate the concentrations. The performances of the proposed sensor are experimentally tested by the use of ternary aqueous solution of sodium chloride and sucrose, which is widely involved in food and beverage industries. This sensor could prove valuable as a process control sensor in industry fields.

  2. Dynamical theory of subconstituents based on ternary algebras

    International Nuclear Information System (INIS)

    Bars, I.; Guenaydin, M.

    1980-01-01

    We propose a dynamical theory of possible fundamental constituents of matter. Our scheme is based on (super) ternary algebras which are building blocks of Lie (super) algebras. Elementary fields, called ''ternons,'' are associated with the elements of a (super) ternary algebra. Effective gauge bosons, ''quarks,'' and ''leptons'' are constructed as composite fields from ternons. We propose two- and four-dimensional (super) ternon theories whose structures are closely related to CP/sub N/ and Yang-Mills theories and their supersymmetric extensions. We conjecture that at large distances (low energies) the ternon theories dynamically produce effective gauge theories and thus may be capable of explaining the present particle-physics phenomenology. Such a scenario is valid in two dimensions

  3. Experimental Investigation of Ternary Alloys for Fusion Breeding Blankets

    Energy Technology Data Exchange (ETDEWEB)

    Choi, B. William [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Chiu, Ing L. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-10-26

    Future fusion power plants based on the deuterium-tritium (DT) fuel cycle will be required to breed the T fuel via neutron reactions with lithium, which will be incorporated in a breeding blanket that surrounds the fusion source. Recent work by LLNL proposed the used of liquid Li as the breeder in an inertial fusion energy (IFE) power plant. Subsequently, an LDRD was initiated to develop alternatives ternary alloy liquid metal breeders that have reduced chemical reactivity with water and air compared to pure Li. Part of the work plan was to experimentally investigate the phase diagrams of ternary alloys. Of particular interest was measurement of the melt temperature, which must be low enough to be compatible with the temperature limits of the steel used in the construction of the chamber and heat transfer system.

  4. Ternary and senary representations using DNA double-crossover tiles.

    Science.gov (United States)

    Kim, Byeonghoon; Jo, Soojin; Son, Junyoung; Kim, Junghoon; Kim, Min Hyeok; Hwang, Si Un; Dugasani, Sreekantha Reddy; Kim, Byung-Dong; Liu, Wing Kam; Kim, Moon Ki; Park, Sung Ha

    2014-03-14

    The information capacity of DNA double-crossover (DX) tiles was successfully increased beyond a binary representation to higher base representations. By controlling the length and the position of DNA hairpins on the DX tile, ternary and senary (base-3 and base-6) digit representations were realized and verified by atomic force microscopy. Also, normal mode analysis was carried out to study the mechanical characteristics of each structure.

  5. Formation of ternary Mg–Cu–Dy bulk metallic glasses

    Indian Academy of Sciences (India)

    Administrator

    showed that a series of ternary Mg–Cu–Dy bulk metallic glasses (BGMs) with a diameter of 4–8 mm were suc- cessfully fabricated in the system with ... rods with the maximum diameter of 6–16 mm are fabri- cated by copper-mold casting .... some minor secondary event, resulting in a large melting point of about 65 K, which ...

  6. Evaluation of Griseofulvin Binary and Ternary Solid Dispersions with HPMCAS

    OpenAIRE

    Al-Obaidi, Hisham; Buckton, Graham

    2009-01-01

    The stability and dissolution properties of griseofulvin binary and ternary solid dispersions were evaluated. Solid dispersions of griseofulvin and hydroxypropyl methylcellulose acetate succinate (HPMCAS) were prepared using the spray drying method. A third polymer, poly[N-(2-hydroxypropyl)methacrylate] (PHPMA), was incorporated to investigate its effect on the interaction of griseofulvin with HPMCAS. In this case, HPMCAS can form H bonds with griseofulvin directly; the addition of PHPMA to t...

  7. Excess isentropic compressibility and speed of sound of the ternary ...

    Indian Academy of Sciences (India)

    Vi, αi and Cp,i are molar volume, cubic expansion coefficient, and the molar heat capacity of pure components, respectively. The excess speed of sound, uE, is estimated in binary and ternary mixtures using the following expression: uE = u − uid = u − (ρidκid s )−1/2,. (5) where ρid is the density of the corresponding ideal ...

  8. Thermoelectric properties of RuSb2Te ternary skutterudites

    Czech Academy of Sciences Publication Activity Database

    Navrátil, Jiří; Plecháček, T.; Drašar, Č.; Laufek, F.

    2013-01-01

    Roč. 42, č. 7 (2013), s. 1864-1869 ISSN 0361-5235 R&D Projects: GA ČR GAP108/10/1315 Institutional support: RVO:61389013 Keywords : RuSb2Te * ternary skutterudite * doping Subject RIV: CA - Inorganic Chemistry Impact factor: 1.675, year: 2013 http://link.springer.com/article/10.1007/s11664-012-2451-5

  9. Diode having trenches in a semiconductor region

    Energy Technology Data Exchange (ETDEWEB)

    Palacios, Tomas Apostol; Lu, Bin; Matioli, Elison de Nazareth

    2016-03-22

    An electrode structure is described in which conductive regions are recessed into a semiconductor region. Trenches may be formed in a semiconductor region, such that conductive regions can be formed in the trenches. The electrode structure may be used in semiconductor devices such as field effect transistors or diodes. Nitride-based power semiconductor devices are described including such an electrode structure, which can reduce leakage current and otherwise improve performance.

  10. Anomalous lattice parameter of magnetic semiconductor alloys

    OpenAIRE

    CAETANO, Clovis; MARQUES, Marcelo; FERREIRA, Luiz G.; TELES, Lara K.

    2009-01-01

    The addition of transition metals (TM) to III-V semiconductors radically changes their electronic, magnetic and structural properties. In contrast to the conventional semiconductor alloys, the lattice parameter in magnetic semiconductor alloys, including the ones with diluted concentration (the diluted magnetic semiconductors - DMS), cannot be determined uniquely from the composition. By using first-principles calculations, we find a direct correlation between the magnetic moment and the anio...

  11. Quality CuInSe2 and Cu(In,Ga)Se2 thin films processed by single-step electrochemical deposition techniques

    Science.gov (United States)

    Papadimitriou, D.; Roupakas, G.; Sáez-Araoz, R.; Lux-Steiner, M.-Ch; Nickel, N. H.; Alamé, S.; Vogt, P.; Kneissl, M.

    2015-05-01

    Ternary CuInSe2 and quaternary Cu(In,Ga)Se2 chalcopyrite semiconductor films with potential applications as solar absorbers were deposited by single-step electrochemical deposition (ECD) on molybdenum coated glass substrates. The films have been structurally characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM) combined with energy dispersive x-ray analysis (EDAX), x-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. Chalcopyrite phase formation was confirmed already in as-deposited films. The crystal structure of the films was further improved by thermal treatment. Element interdiffusion at the chalcopyrite/Mo/glass interface has been prevented by retaining moderate temperatures of deposition (70 °C) and subsequent annealing (300 °C). The SEM/EDAX analysis revealed the presence of CuxSe secondary phases on the surface of ternary films and almost stoichiometric growth of quaternary deposited on top of ternary films. The XRD and Raman analysis confirmed the high quality assessment of the films being almost equal to that of chalcopyrite selenide layers grown by physical vapor deposition at high temperatures (550-750 °C). The surface sensitive XPS analysis confirmed the absence of other impurities in the ECD processed films except from oxygen and carbon adsorbents by sample exposure to atmospheric air.

  12. Ternary Ag/epoxy adhesive with excellent overall performance.

    Science.gov (United States)

    Ji, Yan-Hong; Liu, Yu; Huang, Gui-Wen; Shen, Xiao-Jun; Xiao, Hong-Mei; Fu, Shao-Yun

    2015-04-22

    Excellent electrical conductivity (EC) generally conflicts with high lap shear strength (LSS) for electrically conductive adhesives (ECAs) since EC increases while LSS decreases with increasing conductive filler content. In this work, the ECAs with the excellent overall performance are developed based on the ternary hybrid of Ag microflakes (Ag-MFs), Ag nanospheres (Ag-NSs), and Ag nanowires (Ag-NWs). First, a low silver content adhesive system is determined. Then, the effects of the relative contents of Ag fillers on the EC and the LSS are studied. It is shown that a small amount of Ag-NSs or Ag-NWs can dramatically improve the EC for the Ag-MF/epoxy adhesives. The Ag-NSs and Ag-NWs with appropriate contents have a synergistic effect in improving the EC. Meanwhile, the LSS of the as-prepared adhesive with the appropriate Ag contents reaches an optimal value. Both the EC and the LSS of the as-prepared ternary hybrid ECA with a low content of 40 wt % Ag are higher than those of the commercial ECAs filled with the Ag-MF content over 60 wt %. Finally, the ternary hybrid ECA with the optimal formulation is shown to be promising for printing the radio frequency identification tag antennas as an immediate application example.

  13. Realizing Ternary Logic in FPGAs for SWL DSP Systems

    Directory of Open Access Journals (Sweden)

    Tayeb Din

    2013-07-01

    Full Text Available Recently SWL (Short Word Length DSP (Digital Signal Processing applications has been proposed to overcome multiplier complexity that is evident in most of the digital applications. These SWL applications have been processed through sigma-delta modulation as a key element. For such applications, adder design plays vital role and can impact upon the chip area and its performance. In this paper, a ternary approach for adder tree has been proposed instead of binary that can accommodate more data with less chip-area at the cost of extra pin. The proposed ternary adder tree has been designed and developed in Quartus-II using three different design strategies namely T-gate (Ternary gate, LUT (Look Up Table and algebraic equations. Through rigorous simulation it was found that T-gate technique results in superior performance, an average of 23.5 and 33% improvement compared to the same adder structure based on Boolean Algebraic Equation and LUT, respectively. The proposed adder design would benefit the efficient implementation of SWL applications.

  14. Phase equilibria of the Mo-Al-Ho ternary system

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yitai; Chen, Xiaoxian; Liu, Hao [Guangxi Univ., Nanning (China). College of Materials Science and Engineering; Guangxi Univ., Nanning (China). Guangxi Key Laboratory of Processing for Non-ferrous Metal and Featured Materials; Zhan, Yongzhong [Guangxi Univ., Nanning (China). College of Materials Science and Engineering; Guangxi Univ., Nanning (China). Guangxi Key Laboratory of Processing for Non-ferrous Metal and Featured Materials; Guangxi Univ., Nanning (China). Center of Ecological Collaborative Innovation for Aluminum Industry

    2017-08-15

    Investigation into the reactions and phase equilibria of transition metal elements (i.e. Mo, Zr, Cr, V and Ti), Al and rare earths is academically and industrially important for the development of both refractory alloys and lightweight high-temperature materials. In this work, the equilibria of the Mo-Al-Ho ternary system at 773 K have been determined by using X-ray powder diffraction and scanning electron microscopy equipped with energy dispersive X-ray analysis. A new ternary phase Al{sub 4}Mo{sub 2}Ho has been found and the other ternary phase Al{sub 43}Mo{sub 4}Ho{sub 6} is observed. Ten binary phases in the Al-Mo and Al-Ho systems, including Al{sub 17}Mo{sub 4} rather than Al{sub 4}Mo, have been determined to exist at 773 K. The homogeneity ranges of AlMo{sub 3} and Al{sub 8}Mo{sub 3} phase are 7.5 at.% and 1 at.%, respectively. According to the phase-disappearing method, the maximum solubility of Al in Mo is about 16 at.%.

  15. Ternary fission of 184466,476X formed in U + U collisions

    International Nuclear Information System (INIS)

    Karthikraj, C.; Subramanian, S.; Selvaraj, S.

    2016-01-01

    Recently, the very rare process of nuclear ternary fission has been of great interest in nuclear dynamics. Based on the statistical theory of fission, we discuss here the ternary-fission mass distribution of 184 466,476 X formed in low-energy U + U collisions for different heavy third fragments at T = 1 and 2 MeV. The expected ternary configurations 208 Pb + 208 Pb + 50 Ca and 204 Hg + 204 Hg + 58 Cr are obtained from the ternary fission of 184 466 X at T = 2 MeV. In addition, for both the systems, various possible ternary modes are listed for different heavy third fragments. Our results clearly indicate that the favored ternary configurations have either proton and/or neutron shell closure nucleus as one of their partners. (orig.)

  16. Microstructure of III-N semiconductors related to their applications in optoelectronics

    Science.gov (United States)

    Leszczynski, M.; Czernetzki, R.; Sarzynski, M.; Krysko, M.; Targowski, G.; Prystawko, P.; Bockowski, M.; Grzegory, I.; Suski, T.; Domagala, J.; Porowski, S.

    2005-03-01

    There has been more than a decade since Shuji Nakamura from Japanese company Nichia constructed the first blue LED based on structure of (AlGaIn)N semiconductor and eight years since he made the first blue laser diode (LD). This work gives a survey on the current technological status with green/blue/violet/UV optoelectronics based on III-N semiconductors in relation with their microstructure. The following devices are presented: i) Low-power green and blue LEDs, ii) High-power LEDs targeting solid-state white lighting, iii) Low-power violet LDs for high definition DVD market, iv) High-power violet LDs, v) UV LEDs. The discussion will be focused on three main technological problems related to the microstructure of (AlGaIn)N layers in emitters based on III-N semiconductors: i) high density of dislocations in epitaxial layers of GaN on foreign substrates (sapphire, SiC, GaAs), ii), presence of strains, iii) atom segregation in ternary and quaternary compounds.

  17. Microstructure of III-N semiconductors related to their applications in optoelectronics

    Energy Technology Data Exchange (ETDEWEB)

    Leszczynski, M.; Czernetzki, R. [TopGaN Ltd., Sokolowska 29/37, 01 142 Warsaw (Poland); Sarzynski, M. [Faculty of Physics, Warsaw University of Technology, Koszykowa 75, 00-662 Warsaw (Poland); Krysko, M.; Targowski, G.; Prystawko, P.; Bockowski, M.; Grzegory, I.; Porowski, S. [High Pressure Research Center UNIPRESS, Sokolowska 29/37, 01 142 Warsaw (Poland); TopGaN Ltd., Sokolowska 29/37, 01 142 Warsaw (Poland); Suski, T. [High Pressure Research Center UNIPRESS, Sokolowska 29/37, 01 142 Warsaw (Poland); Domagala, J. [Institute of Physics Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw (Poland)

    2005-03-01

    There has been more than a decade since Shuji Nakamura from Japanese company Nichia constructed the first blue LED based on structure of (AlGaIn)N semiconductor and eight years since he made the first blue laser diode (LD). This work gives a survey on the current technological status with green/blue/violet/UV optoelectronics based on III-N semiconductors in relation with their microstructure. The following devices are presented: i) Low-power green and blue LEDs, ii) High-power LEDs targeting solid-state white lighting, iii) Low-power violet LDs for high definition DVD market, iv) High-power violet LDs, v) UV LEDs. The discussion is focused on three main technological problems related to the microstructure of (AlGaIn)N layers in emitters based on III-N semiconductors: i) high density of dislocations in epitaxial layers of GaN on foreign substrates (sapphire, SiC, GaAs), ii), presence of strains, iii) atom segregation in ternary and quaternary compounds. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  18. Semiconductor technology program: Progress briefs

    Science.gov (United States)

    Galloway, K. F.; Scace, R. I.; Walters, E. J.

    1981-01-01

    Measurement technology for semiconductor materials, process control, and devices, is discussed. Silicon and silicon based devices are emphasized. Highlighted activities include semiinsulating GaAs characterization, an automatic scanning spectroscopic ellipsometer, linewidth measurement and coherence, bandgap narrowing effects in silicon, the evaluation of electrical linewidth uniformity, and arsenicomplanted profiles in silicon.

  19. Towards filament free semiconductor lasers

    DEFF Research Database (Denmark)

    McInerney, John; O'Brien, Peter; Skovgaard, Peter M. W.

    2000-01-01

    We outline physical models and simulations for suppression of self-focusing and filamentation in large aperture semiconductor lasers. The principal technical objective is to generate multi-watt CW or quasi-CW outputs with nearly diffraction limited beams, suitable for long distance free space...

  20. Ultrafast Spectroscopy of Semiconductor Devices

    DEFF Research Database (Denmark)

    Borri, Paola; Langbein, Wolfgang; Hvam, Jørn Marcher

    1999-01-01

    In this work we present an experimental technique for investigating ultrafast carrier dynamics in semiconductor optical amplifiers at room temperature. These dynamics, influenced by carrier heating, spectral hole-burning and two-photon absorption, are very important for device applications in inf...

  1. Semiconductor radiation detectors: device physics

    National Research Council Canada - National Science Library

    Lutz, Gerhard

    1999-01-01

    ..., including nuclear physics, elementary particle physics, optical and x-ray astronomy, medicine, and materials testing - and the number of applications is growing continually. Closely related, and initiated by the application of semiconductors, is the development of low-noise low-power integrated electronics for signal readout. The success of semicond...

  2. Review of semiconductor drift detectors

    Science.gov (United States)

    Gatti, Emilio; Rehak, Pavel

    2005-04-01

    A short review of semiconductor drift detectors is given. The emphasis is given to detectors intended for tracking of fast charged particles for experiments in particle physics and high energy heavy-ion physics. The use and performance of this kind of detector in past, present and future experiments is described together with the experience learned during the design, production and data taking phases.

  3. Atomistic Models of Amorphous Semiconductors

    NARCIS (Netherlands)

    Jarolimek, K.

    2011-01-01

    Crystalline silicon is probably the best studied material, widely used by the semiconductor industry. The subject of this thesis is an intriguing form of this element namely amorphous silicon. It can contain a varying amount of hydrogen and is denoted as a-Si:H. It completely lacks the neat long

  4. 2010 Defects in Semiconductors GRC

    Energy Technology Data Exchange (ETDEWEB)

    Shengbai Zhang

    2011-01-06

    Continuing its tradition of excellence, this Gordon Conference will focus on research at the forefront of the field of defects in semiconductors. The conference will have a strong emphasis on the control of defects during growth and processing, as well as an emphasis on the development of novel defect detection methods and first-principles defect theories. Electronic, magnetic, and optical properties of bulk, thin film, and nanoscale semiconductors will be discussed in detail. In contrast to many conferences, which tend to focus on specific semiconductors, this conference will deal with point and extended defects in a broad range of electronic materials. This approach has proved to be extremely fruitful for advancing fundamental understanding in emerging materials such as wide-band-gap semiconductors, oxides, sp{sup 2} carbon based-materials, and photovoltaic/solar cell materials, and in understanding important defect phenomena such as doping bottleneck in nanostructures and the diffusion of defects and impurities. The program consists of about twenty invited talks and a number of contributed poster sessions. The emphasis should be on work which has yet to be published. The large amount of discussion time provides an ideal forum for dealing with topics that are new and/or controversial.

  5. Towards filament free semiconductor lasers

    DEFF Research Database (Denmark)

    McInerney, John; O'Brien, Peter; Skovgaard, Peter M. W.

    2000-01-01

    We outline physical models and simulations for suppression of self-focusing and filamentation in large aperture semiconductor lasers. The principal technical objective is to generate multi-watt CW or quasi-CW outputs with nearly diffraction limited beams, suitable for long distance free space...... propagation structures in lasers and amplifiers which suppress lateral reflections....

  6. A Brief History of ... Semiconductors

    Science.gov (United States)

    Jenkins, Tudor

    2005-01-01

    The development of studies in semiconductor materials is traced from its beginnings with Michael Faraday in 1833 to the production of the first silicon transistor in 1954, which heralded the age of silicon electronics and microelectronics. Prior to the advent of band theory, work was patchy and driven by needs of technology. However, the arrival…

  7. Calculation of the thermal mode in semiconductor devices in conditions of their operation in semiconductor apparatuses

    OpenAIRE

    Сосков, Анатолій Георгійович; Глєбова, Марина Леонідівна; Сабалаєва, Наталія Олегівна; Форкун, Яна Борисівна

    2014-01-01

    The study of the temperature field of power semiconductor devices, operating in semiconductor apparatuses, either non-contact or hybrid was carried out in the paper.It was also shown that the main mode of the current load of power semiconductor devices, operating in semiconductor apparatuses is a pulse mode.Analytical method for calculating the values of the temperature rise in the structure of power semiconductor devices when subjected to a current pulse of arbitrary shape based on a model t...

  8. Can time reversal invariance be tested in ternary fission?

    International Nuclear Information System (INIS)

    Jesinger, P.; Koetzle, A.; Goennenwein, F.; Schmidt, K.; Gagarski, A. M.; Petrov, G. A.; Petrova, V. I.; Danilyan, G.; Pavlov, V. S.; Chvatchkin, V. B.; Mutterer, M.; Neumaier, S. R.; Nesvizhevsky, V.; Zimmer, O.; Geltenbort, P.; Korobkina, K.

    1998-01-01

    Already several years ago the idea has been put forward that a reaction well suited for tests of Time Reversal Invariance (TRI) might be ternary fission [1][2]. In ternary fission, besides the two main fission fragments, a third (usually light) charged particle is emitted. For a test of TRI a triple correlation has to be studied involving on one hand the momenta of a fission fragment p f and the ternary particle p t , and on the other hand e.g. the spin of the neutron inducing fission s. The correlation coefficient B=s·[p f xp t ] for the respective unit vectors s, p f and p t reverses sign upon time reversal and a non-vanishing expectation value for B could possibly be due to TRI being violated. However, final state interactions could equally well lead to a non-zero B with TRI being perfectly conserved. A first experiment of this type has been performed in early 1998 at the ILL. Placing fragment and ternary particle detectors at right angles both relative to each other and relative to a longitudinally polarized neutron beam, the observable B assumes the values B=±1. For a fixed set of detectors the sign of B is reversed upon flipping the neutron spin. The expected count rates for the two spin orientations are N=N 0 ·(1±D) with N 0 the count rate for an unpolarized beam. The asymmetry D measures the expectation value of the observable B. The reaction chosen was 233 U(n,f). An unexpectedly large correlation coefficient passing all tests of fake asymmetries was observed. From the raw data the expectation value for B is D=-(2.35±0.05)·10 -3 with the sign corresponding to light fragments. Corrections for finite solid angles subtended by the detectors are not included in the above figure. The corrections will further increase the correlation coefficient. At the moment the mere size of D is believed to rule out a failure of TRI as the origin of the effect. But even a less spectacular interpretation--which as yet is not available--should give a detailed and quite

  9. Controlled growth of semiconductor crystals

    Science.gov (United States)

    Bourret-Courchesne, Edith D.

    1992-01-01

    A method for growth of III-V, II-VI and related semiconductor single crystals that suppresses random nucleation and sticking of the semiconductor melt at the crucible walls. Small pieces of an oxide of boron B.sub.x O.sub.y are dispersed throughout the comminuted solid semiconductor charge in the crucible, with the oxide of boron preferably having water content of at least 600 ppm. The crucible temperature is first raised to a temperature greater than the melt temperature T.sub.m1 of the oxide of boron (T.sub.m1 =723.degree. K. for boron oxide B.sub.2 O.sub.3), and the oxide of boron is allowed to melt and form a reasonably uniform liquid layer between the crucible walls and bottom surfaces and the still-solid semiconductor charge. The temperature is then raised to approximately the melt temperature T.sub.m2 of the semiconductor charge material, and crystal growth proceeds by a liquid encapsulated, vertical gradient freeze process. About half of the crystals grown have a dislocation density of less than 1000/cm.sup.2. If the oxide of boron has water content less than 600 ppm, the crucible material should include boron nitride, a layer of the inner surface of the crucible should be oxidized before the oxide of boron in the crucible charge is melted, and the sum of thicknesses of the solid boron oxide layer and liquid boron oxide layer should be at least 50 .mu.m.

  10. Transient photoconductivity in amorphous semiconductors

    International Nuclear Information System (INIS)

    Mpawenayo, P.

    1997-07-01

    Localized states in amorphous semiconductors are divided in disorder induced shallow trap levels and dangling bonds deep states. Dangling bonds are assumed here to be either neutral or charged and their energy distribution is a single gaussian. Here, it is shown analytically that transient photocurrent in amorphous semiconductors is fully controlled by charge carriers transitions between localized states for one part and tunneling hopping carriers on the other. Localized dangling bonds deep states act as non radiative recombination centres, while hopping tunnelling is assisted by the Coulomb interaction between defects sites. The half-width of defects distribution is the disorder parameter that determines the carrier hopping time between defects sites. The macroscopic time that explains the long decay response times observed will all types of amorphous semiconductors is duly thought to be temperature dependent. Basic equations developed by Longeaud and Kleider are solved for the general case of a semiconductor after photo-generation. It turns out that the transient photoconductivity decay has two components; one with short response times from carriers trap-release transitions between shallow levels and extended states and a hopping component made of inter-dependent exponentials whose time constants span in larger ranges depending on disorder. The photoconductivity hopping component appears as an additional term to be added to photocurrents derived from existing models. The results of the present study explain and complete the power law decay derived in the multiple trapping models developed 20 years ago only in the approximation of the short response time regime. The long response time regime is described by the hopping macroscopic time. The present model is verified for all samples of amorphous semiconductors known so far. Finally, it is proposed to improved the modulated photoconductivity calculation techniques by including the long-lasting hopping dark documents

  11. Aluminum nitride, Scandium nitride, and Aluminum-Scandium-Nitride ternary alloys : Structural, optical, and electrical properties

    Science.gov (United States)

    Deng, Ruopeng

    is ideal for shear mode electromechanical coupling, which is maximized at 48°. And this developing bi-axial texture is attributed to evolutionary competitive growth mode which selects out-of-plane and in-plane orientation by nuclei growth rates. In order to determine electronic band structure of ScN, simulation and experimental results are combined. First-principle simulation with HSE exchange function suggests rock-salt ScN to be indirect semiconductor with indirect gap of 0.92 eV and direct gap of 2.02 eV at X point, as well as electron transport effective mass of 0.33+/-0.05 m0 at conduction band bottom. In experiment, epitaxial ScN thin films deposited on single-crystal MgO 001 substrates by reactive sputtering are found unintentionally doped to be degenerate n-type semiconductor with electron density between 1.12x10 20 and 12.8x1020 cm-3. Direct bandgap determined by optic absorption method is observed decreasing with carrier concentration due to Bursten-Moss effect in a roughly linear trend, yielding an extrapolated intrinsic gap value of 2.1 eV at zero carrier density. Electron transport effective mass is also calculated from fitted plasma frequency, which is 0.40+/-0.02 m0. The overall great agreement between simulation and experiment can be concluded in regard of bandgap and effective mass, as well as optic reflectance level. Al-Sc-N ternary alloys can be categorized into two regions: Al-rich wurtizte Al1-xScxN and Sc-rich rock-salt Sc1-xAlxN. For Al1-xScxN, multiple phenomena are observed in experiment as Sc concentration x increases, from epitaxial samples deposited on sapphire 0001 substrates at 850°C: (1) Anisotropic lattice expansion with a = 3.111+0.744x A while c remains at 4.989+/-0.005 A, implying elongation of bond lengths as well as decrease in bond angle from 108.2° towards ~90° corresponding to meta-stable h-ScN. (2) Dielectric constant increases with Sc concentration as epsiloninfinity = 4.15 + 3.2x, correlated to the almost linear

  12. Liquid-liquid equilibria for binary and ternary polymer solutions with PC-SAFT

    DEFF Research Database (Denmark)

    Lindvig, Thomas; Michelsen, Michael Locht; Kontogeorgis, Georgios

    2004-01-01

    are used for investigating the correlative and predictive capabilities of the thermodynamic model PC-SAFT. The investigation shows that the model correlates well experimental LLE data for binary as well as ternary systems but further predicts the behavior of the ternary systems with reasonably good......Two algorithms for evaluating liquid-liquid equilibria (LLE) for binary and ternary polymer solutions are presented. The binary algorithm provides the temperature versus concentration cloud-point curve at fixed pressure, whereas the ternary algorithm provides component 1 versus component 2...

  13. Optimization of Electrochemically Deposited Highly Doped ZnO Bilayers on Ga-Rich Chalcopyrite Selenide for Cost-Effective Photovoltaic Device Technology

    Directory of Open Access Journals (Sweden)

    Dimitra N. Papadimitriou

    2016-11-01

    Full Text Available High quality polycrystalline bilayers of aluminium doped ZnO (Al:ZnO were successively electrodeposited in the form of columnar structures preferentially oriented along the ( 10 1 ¯ 1 crystallographic direction from aqueous solution of zinc nitrate (Zn(NO32 at negative electrochemical potential of EC = (−0.8–(−1.2 V and moderate temperature of 80 °C on gallium rich (30% Ga chalcopyrite selenide Cu(In,GaSe2 (CIGS with chemically deposited ZnSe buffer (ZnSe/Cu(In,GaSe2/Mo/glass. The aluminium doped ZnO layer properties have initially been probed by deposition of Al:ZnO/i-ZnO bilayers directly on Mo/glass substrates. The band-gap energy of the Al:ZnO/i-ZnO reference layers was found to vary from 3.2 to 3.7 eV by varying the AlCl3 solute dopant concentration from 1 to 20 mM. The electrical resistivity of indium-pellet contacted highly doped Al:ZnO sheet of In/Al:ZnO/i-ZnO/Mo/glass reference samples was of the order ρ ~10−5 Ω·cm; the respective carrier concentration of the order 1022 cm−3 is commensurate with that of sputtered Al:ZnO layers. For crystal quality optimization of the bilayers by maintenance of the volatile selenium content of the chalcopyrite, they were subjected to 2-step annealing under successive temperature raise and N2 flux regulation. The hydrostatic compressive strain due to Al3+ incorporation in the ZnO lattice of bilayers processed successively with 5 and 12 mM AlCl3 dopant was εh = −0.046 and the respective stress σh = −20 GPa. The surface reflectivity of maximum 5% over the scanned region of 180–900 nm and the (optical band gap of Eg = 3.67 eV were indicative of the high optical quality of the electrochemically deposited (ECD Al:ZnO bilayers.

  14. Fermi level dependent native defect formation: Consequences for metal-semiconductor and semiconductor-semiconductor interfaces

    International Nuclear Information System (INIS)

    Walukiewicz, W.

    1988-02-01

    The amphoteric native defect model of the Schottky barrier formation is used to analyze the Fermi level pinning at metal/semiconductor interfaces for submonolayer metal coverages. It is assumed that the energy required for defect generation is released in the process of surface back-relaxation. Model calculations for metal/GaAs interfaces show a weak dependence of the Fermi level pinning on the thickness of metal deposited at room temperature. This weak dependence indicates a strong dependence of the defect formation energy on the Fermi level, a unique feature of amphoteric native defects. This result is in very good agreement with experimental data. It is shown that a very distinct asymmetry in the Fermi level pinning on p- and n-type GaAs observed at liquid nitrogen temperatures can be understood in terms of much different recombination rates for amphoteric native defects in those two types of materials. Also, it is demonstrated that the Fermi level stabilization energy, a central concept of the amphoteric defect system, plays a fundamental role in other phenomena in semiconductors such as semiconductor/semiconductor heterointerface intermixing and saturation of free carrier concentration. 33 refs., 6 figs

  15. Modulation spectroscopy characterization of MOCVD semiconductors and semiconductors structures

    Science.gov (United States)

    Pollak, Fred H.; Shen, H.

    1989-11-01

    This paper reviews recent developments in the use of contactless modulation spectroscopy to yield important information about MOCVD growth as well as the properties of MOCVD fabricated semiconductors and semiconductor microstructures. The method of reflectance difference spectroscopy can be used to gain significant insights into chemical and structural parameters during actual growth conditions. The electromodulation technique of photoreflectance (PR) probes the electronic states of the material. It has many applications for in-situ post-growth characterization of crystal quality, very thin Ga 1-xAl xAs/GaAs epitaxial layers, Ga 1-xAl xAs alloy composition, deep trap states, surface electric fields and carrier concentrations, lattice-mismatch strain, etc, as well as the determination of relevant parameters of heterojunction structures. In addition, recent PR experiments at 600°C on GaAs and Ga 0.82Al 0.18As show potential for in-situ monitoring during growth.

  16. Application of the high-pressure thermoelectric technique for characterization of semiconductor microsamples: PbX-based compounds

    International Nuclear Information System (INIS)

    Ovsyannikov, Sergey V; Shchennikov, Vladimir V; Ponosov, Yuri S; Gudina, Svetlana V; Guk, Vera G; Skipetrov, Eugenii P; Mogilenskikh, Viktor E

    2004-01-01

    In this paper the technique of thermoelectric measurements at high pressure was applied for characterization of semiconductor microsamples based on lead chalcogenide compounds (p-PbSe, n-Pb 1-x Sn x Se). The Raman scattering technique at ambient pressure was used as an alternative tool for testing of the samples. Raman measurements have revealed broad peaks at 135 and 265 cm -1 for PbSe and Pb 1-x Sn x Se. Analogous spectra were obtained for PbS, and PbTe-based ternary compounds at higher and lower frequencies, respectively. The peaks have been attributed to the first- and second-order Raman modes. From resistivity and thermoelectric power data the linear decrease in the pressure of the NaCl → GeS structural phase transition with increasing Sn content has been established and the thermopower of high-pressure GeS phases have been determined. Thermoelectric properties of the samples at high pressure have shown high sensitivity to a small variation in the composition of the ternary Pb 1-x Sn x Se compounds, which makes it possible to distinguish semiconductor microsamples whose compositions are very similar

  17. Spectral editing in MAS NMR of aprotic solids. 31P-113Cd cross-polarization and heteronuclear double-quantum filtering studies in II-IV-V2 semiconductor alloys.

    Science.gov (United States)

    Franke, D; Hudalla, C; Eckert, H

    1993-03-01

    Magic-angle-spinning NMR spectra of aprotic solids, ceramics and glasses frequently suffer from poor site resolution due to wide chemical shift distribution effects. In such cases, cross-polarization and heteronuclear double-quantum filtering experiments involving nuclei other than 1H offer unique spectral editing capabilities. The utility of such assignment techniques for examining site populations in semiconductor alloys is demonstrated for the chalcopyrite systems CdGeAs2-xPx, CdSiAs2-xPx and ZnxCd1-xGeP2. The results permit a distinction between local and non-local effects on experimental chemical shift trends and reveal that compositional dependences observed in these alloys are dominated by non-local chemical shift contributions.

  18. Hypersonic modes in nanophononic semiconductors.

    Science.gov (United States)

    Hepplestone, S P; Srivastava, G P

    2008-09-05

    Frequency gaps and negative group velocities of hypersonic phonon modes in periodically arranged composite semiconductors are presented. Trends and criteria for phononic gaps are discussed using a variety of atomic-level theoretical approaches. From our calculations, the possibility of achieving semiconductor-based one-dimensional phononic structures is established. We present results of the location and size of gaps, as well as negative group velocities of phonon modes in such structures. In addition to reproducing the results of recent measurements of the locations of the band gaps in the nanosized Si/Si{0.4}Ge{0.6} superlattice, we show that such a system is a true one-dimensional hypersonic phononic crystal.

  19. Spectroscopic analysis of optoelectronic semiconductors

    CERN Document Server

    Jimenez, Juan

    2016-01-01

    This book deals with standard spectroscopic techniques which can be used to analyze semiconductor samples or devices, in both, bulk, micrometer and submicrometer scale. The book aims helping experimental physicists and engineers to choose the right analytical spectroscopic technique in order to get specific information about their specific demands. For this purpose, the techniques including technical details such as apparatus and probed sample region are described. More important, also the expected outcome from experiments is provided. This involves also the link to theory, that is not subject of this book, and the link to current experimental results in the literature which are presented in a review-like style. Many special spectroscopic techniques are introduced and their relationship to the standard techniques is revealed. Thus the book works also as a type of guide or reference book for people researching in optical spectroscopy of semiconductors.

  20. Semiconductor electrolyte photovoltaic energy converter

    Science.gov (United States)

    Anderson, W. W.; Anderson, L. B.

    1975-01-01

    Feasibility and practicality of a solar cell consisting of a semiconductor surface in contact with an electrolyte are evaluated. Basic components and processes are detailed for photovoltaic energy conversion at the surface of an n-type semiconductor in contact with an electrolyte which is oxidizing to conduction band electrons. Characteristics of single crystal CdS, GaAs, CdSe, CdTe and thin film CdS in contact with aqueous and methanol based electrolytes are studied and open circuit voltages are measured from Mott-Schottky plots and open circuit photo voltages. Quantum efficiencies for short circuit photo currents of a CdS crystal and a 20 micrometer film are shown together with electrical and photovoltaic properties. Highest photon irradiances are observed with the GaAs cell.

  1. Semiconductor Nanowires: Epitaxy and Applications

    OpenAIRE

    Mårtensson, Thomas

    2008-01-01

    Semiconductor nanowires are nanoscale objects formed by bottom-up synthesis. In recent years their unique properties have been exploited in fields such as electronics, photonics, sensors and the life sciences. In this work, the epitaxial growth of nanowires and their applications were studied. Heteroepitaxial growth of III-V nanowires on silicon substrates was demonstrated. This may enable direct band gap materials for optoelectronic devices, as well as high-mobility, low-contact resis...

  2. Quantum correlations in semiconductor microcavities

    Science.gov (United States)

    Kira, M.; Hoyer, W.; Koch, S. W.; Brick, P.; Ell, C.; Hübner, M.; Khitrova, G.; Gibbs, H. M.

    2003-10-01

    The quantum mechanical nature of the light field in semiconductor microcavities leads to non-classical coupling effects between photons and electron-hole excitations. It is shown that these quantum correlations give rise to characteristic corrections of the semiclassical light-matter coupling dynamics. Examples of quantum correlation signatures include entanglement effects in the probe reflection of a microcavity system and squeezing in the incoherent emission.

  3. Modeling of Microwave Semiconductor Diodes

    Directory of Open Access Journals (Sweden)

    Z. Raida

    2008-09-01

    Full Text Available The paper deals with the multi-physical mode-ling of microwave diodes. The electrostatic, drift-diffusion and thermal phenomena are considered in the physical model of the components. The basic semiconductor equati-ons are summarized, and modeling issues are discussed. The simulations of the Gunn Effect in transferred electron devices and the carrier injection effect in PIN diodes are investigated and discussed. The analysis was performed in COMSOL Multiphysics using the finite element method.

  4. Modeling of Microwave Semiconductor Diodes

    OpenAIRE

    Pokorny, M.; Raida, Zbyněk

    2008-01-01

    The paper deals with the multi-physical mode-ling of microwave diodes. The electrostatic, drift-diffusion and thermal phenomena are considered in the physical model of the components. The basic semiconductor equati-ons are summarized, and modeling issues are discussed. The simulations of the Gunn Effect in transferred electron devices and the carrier injection effect in PIN diodes are investigated and discussed. The analysis was performed in COMSOL Multiphysics using the finite element method.

  5. Optoelectronics with 2D semiconductors

    Science.gov (United States)

    Mueller, Thomas

    2015-03-01

    Two-dimensional (2D) atomic crystals, such as graphene and layered transition-metal dichalcogenides, are currently receiving a lot of attention for applications in electronics and optoelectronics. In this talk, I will review our research activities on electrically driven light emission, photovoltaic energy conversion and photodetection in 2D semiconductors. In particular, WSe2 monolayer p-n junctions formed by electrostatic doping using a pair of split gate electrodes, type-II heterojunctions based on MoS2/WSe2 and MoS2/phosphorene van der Waals stacks, 2D multi-junction solar cells, and 3D/2D semiconductor interfaces will be presented. Upon optical illumination, conversion of light into electrical energy occurs in these devices. If an electrical current is driven, efficient electroluminescence is obtained. I will present measurements of the electrical characteristics, the optical properties, and the gate voltage dependence of the device response. In the second part of my talk, I will discuss photoconductivity studies of MoS2 field-effect transistors. We identify photovoltaic and photoconductive effects, which both show strong photoconductive gain. A model will be presented that reproduces our experimental findings, such as the dependence on optical power and gate voltage. We envision that the efficient photon conversion and light emission, combined with the advantages of 2D semiconductors, such as flexibility, high mechanical stability and low costs of production, could lead to new optoelectronic technologies.

  6. Identification of defects in semiconductors

    CERN Document Server

    Stavola, Michael; Weber, Eicke R; Stavola, Michael

    1998-01-01

    Since its inception in 1966, the series of numbered volumes known as Semiconductors and Semimetals has distinguished itself through the careful selection of well-known authors, editors, and contributors.The"Willardson and Beer"Series, as it is widely known, has succeeded in publishing numerous landmark volumes and chapters. Not only did many of these volumes make an impact at the time of their publication, but they continue to be well-cited years after their original release. Recently, Professor Eicke R. Weber of the University of California at Berkeley joined as a co-editor of the series. Professor Weber, a well-known expert in the field of semiconductor materials, will further contribute to continuing the series' tradition of publishing timely, highly relevant, and long-impacting volumes. Some of the recent volumes, such as Hydrogen in Semiconductors, Imperfections in III/V Materials, Epitaxial Microstructures, High-Speed Heterostructure Devices,Oxygen in Silicon, and others promise indeed that this traditi...

  7. Dry etching technology for semiconductors

    CERN Document Server

    Nojiri, Kazuo

    2015-01-01

    This book is a must-have reference to dry etching technology for semiconductors, which will enable engineers to develop new etching processes for further miniaturization and integration of semiconductor integrated circuits.  The author describes the device manufacturing flow, and explains in which part of the flow dry etching is actually used. The content is designed as a practical guide for engineers working at chip makers, equipment suppliers and materials suppliers, and university students studying plasma, focusing on the topics they need most, such as detailed etching processes for each material (Si, SiO2, Metal etc) used in semiconductor devices, etching equipment used in manufacturing fabs, explanation of why a particular plasma source and gas chemistry are used for the etching of each material, and how to develop etching processes.  The latest, key technologies are also described, such as 3D IC Etching, Dual Damascene Etching, Low-k Etching, Hi-k/Metal Gate Etching, FinFET Etching, Double Patterning ...

  8. Indirect-to-direct band gap transition in relaxed and strained Ge{sub 1−x−y}Si{sub x}Sn{sub y} ternary alloys

    Energy Technology Data Exchange (ETDEWEB)

    Attiaoui, Anis; Moutanabbir, Oussama [Department of Engineering Physics, École Polytechnique de Montréal, Montréal, C.P. 6079, Succ. Centre-Ville, Montréal, Québec H3C 3A7 (Canada)

    2014-08-14

    Sn-containing group IV semiconductors create the possibility to independently control strain and band gap thus providing a wealth of opportunities to develop an entirely new class of low dimensional systems, heterostructures, and silicon-compatible electronic and optoelectronic devices. With this perspective, this work presents a detailed investigation of the band structure of strained and relaxed Ge{sub 1−x−y}Si{sub x}Sn{sub y} ternary alloys using a semi-empirical second nearest neighbors tight binding method. This method is based on an accurate evaluation of the deformation potential constants of Ge, Si, and α-Sn using a stochastic Monte-Carlo approach as well as a gradient based optimization method. Moreover, a new and efficient differential evolution approach is also developed to accurately reproduce the experimental effective masses and band gaps. Based on this, we elucidated the influence of lattice disorder, strain, and composition on Ge{sub 1−x−y}Si{sub x}Sn{sub y} band gap energy and directness. For 0 ≤ x ≤ 0.4 and 0 ≤ y ≤ 0.2, we found that tensile strain lowers the critical content of Sn needed to achieve a direct band gap semiconductor with the corresponding band gap energies below 0.76 eV. This upper limit decreases to 0.43 eV for direct gap, fully relaxed ternary alloys. The obtained transition to direct band gap is given by y > 0.605 × x + 0.077 and y > 1.364 × x + 0.107 for epitaxially strained and fully relaxed alloys, respectively. The effects of strain, at a fixed composition, on band gap directness were also investigated and discussed.

  9. Evaporation behaviour of the ternary uranium plutonium carbides

    International Nuclear Information System (INIS)

    Ohse, R.W.; Capone, F.

    1976-01-01

    Simultaneous measurement of total and partial pressures; variation of plutonium pressure with 1/T in the single phase region MC from C/M = 1.014 to 1.15 and two-phase region MC + M 2 C 3 from C/M = 1.15 to 1.30 from 2,000 K to 2,500 K and determination of the corresponding sublimation heat from the measured values; pressure composition diagram of the ternary (U,Pu) carbides giving the phase boundaries between MC and MC + M 2 C 3 phase fields. (RB) [de

  10. (Liquid + liquid) equilibria of (water + butyric acid + esters) ternary systems

    International Nuclear Information System (INIS)

    Kirbaslar, S. Ismail; Sahin, Selin; Bilgin, Mehmet

    2007-01-01

    (Liquid + liquid) equilibrium (LLE) data of the solubility (binodal) curves and tie-line end compositions were examined for mixtures of {water (1) + butyric acid (2) + ethyl propionate or dimethyl phthalate or dibutyl phthalate (3)} at T = 298.15 K and (101.3 ± 0.7) kPa. The relative mutual solubility of the butyric acid is higher in the layers of esters than in the aqueous layer. The reliability of the experimental tie-line data was confirmed by using the Othmer-Tobias correlation. The LLE data of the ternary systems were predicted by UNIFAC method. Distribution coefficients and separation factors were evaluated for the immiscibility region

  11. (Liquid + liquid) equilibria of (water + lactic acid + alcohol) ternary systems

    Energy Technology Data Exchange (ETDEWEB)

    Sahin, Selin [Istanbul University, Engineering Faculty, Chemical Engineering Department, 34320 Avcilar, Istanbul (Turkey); Ismail Kirbaslar, S. [Istanbul University, Engineering Faculty, Chemical Engineering Department, 34320 Avcilar, Istanbul (Turkey)], E-mail: krbaslar@istanbul.edu.tr; Bilgin, Mehmet [Istanbul University, Engineering Faculty, Chemical Engineering Department, 34320 Avcilar, Istanbul (Turkey)

    2009-01-15

    (Liquid + liquid) equilibrium (LLE) measurements of the solubility (binodal) curves and tie-line end compositions were carried out for {l_brace}water (1) + lactic acid (2) + octanol, or nonanol, or decanol (3){r_brace} at T = 298.15 K and 101.3 {+-} 0.7 kPa. The relative mutual solubility of lactic acid is higher in the water layers than in the organic layers. The reliability of the experimental tie-line data was confirmed by using the Othmer-Tobias correlation. The LLE results for the ternary systems were predicted by UNIFAC method. Distribution coefficients and separation factors were evaluated for the immiscibility region.

  12. (Liquid + liquid) equilibria of (water + propionic acid + alcohol) ternary systems

    Energy Technology Data Exchange (ETDEWEB)

    Kirbaslar, S. Ismail [Istanbul University, Engineering Faculty, Chemical Engineering Department, 34320 Avcilar, Istanbul (Turkey)]. E-mail: krbaslar@istanbul.edu.tr; Sahin, Selin [Istanbul University, Engineering Faculty, Chemical Engineering Department, 34320 Avcilar, Istanbul (Turkey); Bilgin, Mehmet [Istanbul University, Engineering Faculty, Chemical Engineering Department, 34320 Avcilar, Istanbul (Turkey)

    2006-12-15

    (Liquid + liquid) equilibrium (LLE) data of the solubility (binodal) curves and tie-line end composition were examined for mixtures of {l_brace}water (1) + propionic acid (2) + octanol or nonanol or decanol or dodecanol (3){r_brace} at T = 298.15 K and 101.3 {+-} 0.7 kPa. The reliability of the experimental tie-line data was confirmed by using the Othmer-Tobias correlation. The LLE data of the ternary systems were predicted by UNIFAC method. Distribution coefficients and separation factors were evaluated for the immiscibility region.

  13. Paramagnetic centers in ternary coordinated oxygen in beryllium aluminosilicate glasses

    International Nuclear Information System (INIS)

    Blaginina, L.A.; Zatsepin, A.F.; Dmitriev, I.A.

    1988-01-01

    Glasses of the composition 3BeO-Al 2 O 3 -6SiO 2 containing a homogenizing additive of MgF 2 were synthesized. The ESR spectra of x-ray and gamma irradiated specimens were determined. A complex ESR spectrum arose in the original glass. The ESR spectrum of the gamma-irradiated polycrystalline Be 2 SiO 4 glass was almost identical to the crystallized glass. It was shown that the presence of beryllium atoms in the composition of silicate glasses created the conditions for the formation of structural fragments with ternary coordinated oxygen

  14. Quantifying the energetics of cooperativity in a ternary protein complex

    DEFF Research Database (Denmark)

    Andersen, Peter S; Schuck, Peter; Sundberg, Eric J

    2002-01-01

    and mathematical modeling to describe the energetics of cooperativity in a trimolecular protein complex. As a model system for quantifying cooperativity, we studied the ternary complex formed by the simultaneous interaction of a superantigen with major histocompatibility complex and T cell receptor, for which...... a structural model is available. This system exhibits positive and negative cooperativity, as well as augmentation of the temperature dependence of binding kinetics upon the cooperative interaction of individual protein components in the complex. Our experimental and theoretical analysis may be applicable...... to other systems involving cooperativity....

  15. Implementation of DFT application on ternary optical computer

    Science.gov (United States)

    Junjie, Peng; Youyi, Fu; Xiaofeng, Zhang; Shuai, Kong; Xinyu, Wei

    2018-03-01

    As its characteristics of huge number of data bits and low energy consumption, optical computing may be used in the applications such as DFT etc. which needs a lot of computation and can be implemented in parallel. According to this, DFT implementation methods in full parallel as well as in partial parallel are presented. Based on resources ternary optical computer (TOC), extensive experiments were carried out. Experimental results show that the proposed schemes are correct and feasible. They provide a foundation for further exploration of the applications on TOC that needs a large amount calculation and can be processed in parallel.

  16. Ternary system of cesium, rubidium and lead iodides

    International Nuclear Information System (INIS)

    Volchanskaya, V.V.; Dunaeva, T.I.; Il'yasov, I.I.

    1990-01-01

    Meltability diagram of ternary system (CsI) 2 -(RbI) 2 -PbI 2 has been studied. The liquidus of the given system consists of crystallization fields of solid solutions (CsI-RbI) and (CsI·PbI 2 -RbI-PbI 2 ), fields of incongruently melting compounds 9RbI·PbI 2 , 4CsI·PbI 2 and field of PbI 2 component. In the system two nonvariant points at 410 and 380 deg C are detected

  17. Electrical resistivity of liquid binary and ternary alloys

    International Nuclear Information System (INIS)

    Ornat, M.; Paja, A.

    2011-01-01

    New method of calculation of the electrical resistivity of liquid and amorphous alloys is presented. The method is based on the Morgan-Howson-Saub (MHS) model but the pseudopotentials are replaced by the scattering matrix operators. The Fermi energy is properly determined by the accurate values of the phase shifts. The model depends on a very small number of universal parameters and gives stable results. The calculated values of the resistivity agree well with available experimental data for a substantial number of binary alloys. Moreover, the results for some ternary alloys were also obtained. (orig.)

  18. Phase diagram of the ternary Zr-Ti-Sn system

    International Nuclear Information System (INIS)

    Arias, D.; Gonzalez Camus, M.

    1987-01-01

    It is well known that Ti stabilizes the high temperature cubic phase of Zr and that Sn stabilizes the low temperature hexagonal phase of Zr. The effect of Sn on the Zr-Ti diagram has been studied in the present paper. Using high purity metals, nine different alloys have been prepared, with 4-32 at % Ti, 0.7-2.2 at % Sn and Zr till 100%. Resistivity and optical and SEM metallography techniques have been employed. Effect of some impurities have been analyzed. The results are discussed and different isothermic sections of the ternary Zr-Ti-Sn diagram are presented. (Author) [es

  19. Plutonium microstructures. Part 2. Binary and ternary alloys

    International Nuclear Information System (INIS)

    Cramer, E.M.; Bergin, J.B.

    1983-12-01

    This report is the second of three parts that exhibit illustrations of inclusions in plutonium metal from inherent and tramp impurities, of intermetallic and nonmetallic constituents from alloy additions, and of the effects of thermal and mechanical treatments. This part includes illustrations of the microstructures in binary cast alloys and a few selected ternary alloys that result from measured additions of diluent elements, and of the microconstituents that are characteristic of phase fields in extended alloy systems. Microhardness data are given and the etchant used in the preparation of each sample is described

  20. Morphology and optical properties of ternary Zn-Sn-O semiconductor nanowires with catalyst-free growth

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Yuan-Chang, E-mail: yuanvictory@gmail.com [Institute of Materials Engineering, National Taiwan Ocean University, Keelung 20224, Taiwan (China); Huang, Chiem-Lum; Hu, Chia-Yen; Deng, Xian-Shi; Zhong, Hua [Institute of Materials Engineering, National Taiwan Ocean University, Keelung 20224, Taiwan (China)

    2012-10-05

    Highlights: Black-Right-Pointing-Pointer Zn{sub 2}SnO{sub 4} nanowires with various morphologies were successfully synthesized by thermal evaporation. Black-Right-Pointing-Pointer The as-synthesized Zn{sub 2}SnO{sub 4} nanowires have a face-centered cubic crystal structure. Black-Right-Pointing-Pointer Thermal annealing of Zn{sub 2}SnO{sub 4} nanowires changes the properties of the visible emission band. - Abstract: This study reports the synthesis of Zn{sub 2}SnO{sub 4} (ZTO) nanowires with various morphologies using thermal evaporation without a metal catalyst. X-ray diffraction patterns show that the structure of the as-synthesized ZTO nanowires is a face-centered cubic spinel phase. Scanning electron microscopy images exhibit that the as-synthesized nanowires have various morphologies, and homogeneously cover the area of interest. High-resolution transmittance electron microscopy reveals that these ZTO nanowires have single crystalline microstructures with four morphologies. The results of low-temperature cathodoluminescence (CL) measurements show the crystal defects of oxygen vacancies and interstitials may contribute to blue-green and yellow-orange emissions, respectively, for the as-synthesized single nanowire. This study also discusses the effects of thermal annealing under oxygen-rich and reducing ambient on the CL properties of the single ZTO nanowire.

  1. Synthesis of g-C3N4-based NaYF4:Yb,Tm@TiO2 ternary composite with enhanced Vis/NIR-driven photocatalytic activities

    Science.gov (United States)

    Cheng, Erjian; Zhou, Shiqi; Li, Mohua; Li, Zhengquan

    2017-07-01

    Upconversion (UC) NaYF4:Yb,Tm nanocrystals (NCs) are capable of converting low-energy near-infrared (NIR) photons to high-energy ultraviolet (UV) and visible (Vis) photons. Integration of NaYF4:Yb,Tm with graphitic carbon nitride (g-C3N4) can extend the spectral response of g-C3N4 to the NIR range. However, photocatalytic activity of NaYF4:Yb,Tm/g-C3N4 is still severely limited by the high recombination rate of photo-generated (PG) electrons and holes (e-/h+) in the g-C3N4. Herein, we report a facile approach to fabricate a ternary nanocomposite consisting of NaYF4:Yb,Tm, TiO2 and g-C3N4. When NaYF4:Yb,Tm NCs were coated with a TiO2 shell and sequentially assembled with g-C3N4 nanosheets (NSs), a semiconductor heterojunction can be fabricated on the UC particles. The as-prepared nanocomposites possess an enhanced photocatalytic activity under Vis and/or NIR lights due to the formation of heterojunction and UC effect. The ternary nanocomposites have been characterized in detail and their photocatalytic mechanism is proposed. Such kind of ternary nanocomposites may provide a new scenario for the design and synthesis of composite photocatalysts for efficiently utilizing the Vis/NIR lights in environmental remedy.

  2. A refracto-densimetric method for composition analysis of homogeneous ternary liquid mixtures

    OpenAIRE

    Martinez, Fleming; Rojas, Jaime

    2009-01-01

    A new method for composition analysis of homogeneous ternary liquid mixtures is presented. The method is based in the determination of refractive index and density of the unknown mixture. These values are localized in triangular diagrams of thermo-physical properties for the ternary system. The mixture composition correspond to the interception point of the isooptic and isopycnic curves.

  3. Fullerene alloy formation and the benefits for efficient printing of ternary blend organic solar cells

    DEFF Research Database (Denmark)

    Angmo, Dechan; Bjerring, Morten; Nielsen, Niels Chr.

    2015-01-01

    with a third polymer component, the system exhibits pseudo-binary phase behaviour instead of the expected ternary phase behaviour. Our results experimentally confirm the earlier hypothesis that the unexpected composition average dependent IV-behaviour for these supposed ternary mixtures are indeed due to them...

  4. Using a Ternary Diagram to Display a System's Evolving Energy Distribution

    Science.gov (United States)

    Brazzle, Bob; Tapp, Anne

    2016-01-01

    A ternary diagram is a graphical representation used for systems with three components. They are familiar to mineralogists (who typically use them to categorize varieties of solid solution minerals such as feldspar) but are not yet widely used in the physics community. Last year the lead author began using ternary diagrams in his introductory…

  5. Detection of the ternary alpha particles from 252Cr spontaneous source with timepix pixeleted detector

    International Nuclear Information System (INIS)

    Ahmadov, G.S.; Telezhnikov, S.A.; Ahmadov, F.I.; Garibov, A.A.; Ahmadov, G.S.; Ahmadov, F.I.; Granja, C.; Pospisil, S.

    2013-01-01

    A third charged particle is emitted besides the two main fission fragments in ternary fission. Because of the ternary fission is a unique tool to explore the dynamics and structure of atomic nuclei by probing the fissioning system near the scission point and observing fissioning reaction and decay mechanisms main tool to study nuclear fission processes

  6. Experimental investigation of phase equilibria in the Co-W-V ternary system

    International Nuclear Information System (INIS)

    Liu Xingjun; Zhu Yihong; Yu Yan; Wang Cuiping

    2011-01-01

    Highlights: → Three isothermal sections of the Co-W-V ternary system at 1100 deg. C, 1200 deg. C and 1300 deg. C were determined. → No ternary compound was found in the Co-W-V ternary system. → A stable liquid miscibility gap is newly discovered in the Co-W-V ternary system. → This work is of great essence to establish the thermodynamic database for the Co-based alloys. - Abstract: The phase equilibria in the Co-W-V ternary system were experimentally investigated by optical microscopy (OM), electron probe microanalysis (EPMA) and X-ray diffraction (XRD) on the equilibrated alloys. Three isothermal sections of the Co-W-V ternary system at 1100 deg. C, 1200 deg. C and 1300 deg. C were determined, and no ternary compound was found in this system. In addition, a novel phenomena induced by the liquid phase separation in the Co-W-V alloys was firstly discovered, suggesting that a stable liquid miscibility gap exists in the Co-W-V ternary system. The newly determined phase equilibria and firstly discovered phase separation phenomena in the Co-W-V system will provide important information for the development of Co-W based alloys.

  7. Asymmetry in ternary fission induced by polarized neutrons and fission mechanism

    International Nuclear Information System (INIS)

    Bunakov, V.E.; Gennenvajn, F.; Dzhessinger, P.; Mutterer, M.; Petrov, G.A.

    2003-01-01

    The results of measuring the P-odd, P-even (right-left) and T-odd asymmetries of the charged particles emission in the double and ternary fission, induced by the polarized neutrons, are considered. It is shown, what kind of information on the mechanism of the ternary nuclear fission may be obtained from the theoretical analysis of these data [ru

  8. INTERVAL-VALUED INTUITIONISTIC FUZZY BI-IDEALS IN TERNARY SEMIRINGS

    Directory of Open Access Journals (Sweden)

    D. KRISHNASWAMY

    2016-04-01

    Full Text Available In this paper we introduce the notions of interval-valued fuzzy bi-ideal, interval-valued anti fuzzy bi-ideal and interval-valued intuitionistic fuzzy bi-ideal in ternary semirings and some of the basic properties of these ideals are investigated. We also introduce normal interval-valued intuitionistic fuzzy ideals in ternary semirings.

  9. New Icosahedral Boron Carbide Semiconductors

    Science.gov (United States)

    Echeverria Mora, Elena Maria

    Novel semiconductor boron carbide films and boron carbide films doped with aromatic compounds have been investigated and characterized. Most of these semiconductors were formed by plasma enhanced chemical vapor deposition. The aromatic compound additives used, in this thesis, were pyridine (Py), aniline, and diaminobenzene (DAB). As one of the key parameters for semiconducting device functionality is the metal contact and, therefore, the chemical interactions or band bending that may occur at the metal/semiconductor interface, X-ray photoemission spectroscopy has been used to investigate the interaction of gold (Au) with these novel boron carbide-based semiconductors. Both n- and p-type films have been tested and pure boron carbide devices are compared to those containing aromatic compounds. The results show that boron carbide seems to behave differently from other semiconductors, opening a way for new analysis and approaches in device's functionality. By studying the electrical and optical properties of these films, it has been found that samples containing the aromatic compound exhibit an improvement in the electron-hole separation and charge extraction, as well as a decrease in the band gap. The hole carrier lifetimes for each sample were extracted from the capacitance-voltage, C(V), and current-voltage, I(V), curves. Additionally, devices, with boron carbide with the addition of pyridine, exhibited better collection of neutron capture generated pulses at ZERO applied bias, compared to the pure boron carbide samples. This is consistent with the longer carrier lifetimes estimated for these films. The I-V curves, as a function of external magnetic field, of the pure boron carbide films and films containing DAB demonstrate that significant room temperature negative magneto-resistance (> 100% for pure samples, and > 50% for samples containing DAB) is possible in the resulting dielectric thin films. Inclusion of DAB is not essential for significant negative magneto

  10. Multinary I-III-VI2 and I2-II-IV-VI4 Semiconductor Nanostructures for Photocatalytic Applications.

    Science.gov (United States)

    Regulacio, Michelle D; Han, Ming-Yong

    2016-03-15

    are the multinary chalcogenide semiconductors (MCSs), which include the ternary I-III-VI2 semiconductors (e.g., AgGaS2, CuInS2, and CuInSe2) and the quaternary I2-II-IV-VI4 semiconductors (e.g., Cu2ZnGeS4, Cu2ZnSnS4, and Ag2ZnSnS4). These inorganic compounds consist of environmentally benign elemental components, exhibit excellent light-harvesting properties, and possess band gap energies that are well-suited for solar photon absorption. Moreover, the band structures of these materials can be conveniently modified through alloying to boost their ability to harvest visible photons. In this Account, we provide a summary of recent research on the use of ternary I-III-VI2 and quaternary I2-II-IV-VI4 semiconductor nanostructures for light-induced photocatalytic applications, with focus on hydrogen production and organic dye degradation. We include a review of the solution-based methods that have been employed to prepare multinary chalcogenide semiconductor nanostructures of varying compositions, sizes, shapes, and crystal structures, which are factors that are known to have significant influence on the photocatalytic activity of semiconductor photocatalysts. The enhancement of photocatalytic performance through creation of hybrid nanoscale architectures is also presented. Lastly, views on the current challenges and future directions are discussed in the concluding section.

  11. Energy dissipation in the process of ternary fission in heavy nuclear reaction

    International Nuclear Information System (INIS)

    Li Xian; Wang Chengqian; Yan Shiwei

    2015-01-01

    We studied the evolution of the collective motion, interaction potential, the total kinetic and excitation energies in ternary fissions of 197 Au + 197 Au system at 15 MeV/u, and discussed energy dissipation of this reaction. Through the comparison with energy-angle correlation data in binary fissions, we preliminarily concluded that the rst fission of ternary fission was an extreme deep-inelastic process. We further analyzed the correlation of the total kinetic energy with impact parameters in both binary and ternary reactions, and found that the total energy of binary reactions systems was lost about 150 MeV more than ternary fission with small impact parameters, and with larger impact parameters the total energy of ternary reactions were lost 300 MeV more than binary reactions. (authors)

  12. First-principles study of ternary fcc solution phases from special quasirandom structures

    International Nuclear Information System (INIS)

    Shin Dongwon; Wang Yi; Liu Zikui; Walle, Axel van de

    2007-01-01

    In the present work, ternary special quasirandom structures (SQSs) for a fcc solid solution phase are generated at different compositions, x A =x B =x C =(1/3) and x A =(1/2), x B =x C =(1/4), whose correlation functions are satisfactorily close to those of a random fcc solution. The generated SQSs are used to calculate the mixing enthalpy of the fcc phase in the Ca-Sr-Yb system. It is observed that first-principles calculations of all the binary and ternary SQSs in the Ca-Sr-Yb system exhibit very small local relaxation. It is concluded that the fcc ternary SQSs can provide valuable information about the mixing behavior of the fcc ternary solid solution phase. The SQSs presented in this work can be widely used to study the behavior of ternary fcc solid solutions

  13. Electronic properties of semiconductor surfaces and metal/semiconductor interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Tallarida, M.

    2005-05-15

    This thesis reports investigations of the electronic properties of a semiconductor surface (silicon carbide), a reactive metal/semiconductor interface (manganese/silicon) and a non-reactive metal/semiconductor interface (aluminum-magnesium alloy/silicon). The (2 x 1) reconstruction of the 6H-SiC(0001) surface has been obtained by cleaving the sample along the (0001) direction. This reconstruction has not been observed up to now for this compound, and has been compared with those of similar elemental semiconductors of the fourth group of the periodic table. This comparison has been carried out by making use of photoemission spectroscopy, analyzing the core level shifts of both Si 2p and C 1s core levels in terms of charge transfer between atoms of both elements and in different chemical environments. From this comparison, a difference between the reconstruction on the Si-terminated and the C-terminated surface was established, due to the ionic nature of the Si-C bond. The growth of manganese films on Si(111) in the 1-5 ML thickness range has been studied by means of LEED, STM and photoemission spectroscopy. By the complementary use of these surface science techniques, two different phases have been observed for two thickness regimes (<1 ML and >1 ML), which exhibit a different electronic character. The two reconstructions, the (1 x 1)-phase and the ({radical}3 x {radical}3)R30 -phase, are due to silicide formation, as observed in core level spectroscopy. The growth proceeds via island formation in the monolayer regime, while the thicker films show flat layers interrupted by deep holes. On the basis of STM investigations, this growth mode has been attributed to strain due to lattice mismatch between the substrate and the silicide. Co-deposition of Al and Mg onto a Si(111) substrate at low temperature (100K) resulted in the formation of thin alloy films. By varying the relative content of both elements, the thin films exhibited different electronic properties

  14. Roadmap on semiconductor-cell biointerfaces

    Science.gov (United States)

    Tian, Bozhi; Xu, Shuai; Rogers, John A.; Cestellos-Blanco, Stefano; Yang, Peidong; Carvalho-de-Souza, João L.; Bezanilla, Francisco; Liu, Jia; Bao, Zhenan; Hjort, Martin; Cao, Yuhong; Melosh, Nicholas; Lanzani, Guglielmo; Benfenati, Fabio; Galli, Giulia; Gygi, Francois; Kautz, Rylan; Gorodetsky, Alon A.; Kim, Samuel S.; Lu, Timothy K.; Anikeeva, Polina; Cifra, Michal; Krivosudský, Ondrej; Havelka, Daniel; Jiang, Yuanwen

    2018-05-01

    This roadmap outlines the role semiconductor-based materials play in understanding the complex biophysical dynamics at multiple length scales, as well as the design and implementation of next-generation electronic, optoelectronic, and mechanical devices for biointerfaces. The roadmap emphasizes the advantages of semiconductor building blocks in interfacing, monitoring, and manipulating the activity of biological components, and discusses the possibility of using active semiconductor-cell interfaces for discovering new signaling processes in the biological world.

  15. Halo Formation During Solidification of Refractory Metal Aluminide Ternary Systems

    Science.gov (United States)

    D'Souza, N.; Feitosa, L. M.; West, G. D.; Dong, H. B.

    2018-02-01

    The evolution of eutectic morphologies following primary solidification has been studied in the refractory metal aluminide (Ta-Al-Fe, Nb-Al-Co, and Nb-Al-Fe) ternary systems. The undercooling accompanying solid growth, as related to the extended solute solubility in the primary and secondary phases can be used to account for the evolution of phase morphologies during ternary eutectic solidification. For small undercooling, the conditions of interfacial equilibrium remain valid, while in the case of significant undercooling when nucleation constraints occur, there is a departure from equilibrium leading to unexpected phases. In Ta-Al-Fe, an extended solubility of Fe in σ was observed, which was consistent with the formation of a halo of μ phase on primary σ. In Nb-Al-Co, a halo of C14 is formed on primary CoAl, but very limited vice versa. However, in the absence of a solidus projection it was not possible to definitively determine the extended solute solubility in the primary phase. In Nb-Al-Fe when nucleation constraints arise, the inability to initiate coupled growth of NbAl3 + C14 leads to the occurrence of a two-phase halo of C14 + Nb2Al, indicating a large undercooling and departure from equilibrium.

  16. Genetic Synthesis of New Reversible/Quantum Ternary Comparator

    Directory of Open Access Journals (Sweden)

    DEIBUK, V.

    2015-08-01

    Full Text Available Methods of quantum/reversible logic synthesis are based on the use of the binary nature of quantum computing. However, multiple-valued logic is a promising choice for future quantum computer technology due to a number of advantages over binary circuits. In this paper we have developed a synthesis of ternary reversible circuits based on Muthukrishnan-Stroud gates using a genetic algorithm. The method of coding chromosome is presented, and well-grounded choice of algorithm parameters allowed obtaining better circuit schemes of one- and n-qutrit ternary comparators compared with other methods. These parameters are quantum cost of received reversible devices, delay time and number of constant input (ancilla lines. Proposed implementation of the genetic algorithm has led to reducing of the device delay time and the number of ancilla qutrits to 1 and 2n-1 for one- and n-qutrits full comparators, respectively. For designing of n-qutrit comparator we have introduced a complementary device which compares output functions of 1-qutrit comparators.

  17. A ternary logic model for recurrent neuromime networks with delay.

    Science.gov (United States)

    Hangartner, R D; Cull, P

    1995-07-01

    In contrast to popular recurrent artificial neural network (RANN) models, biological neural networks have unsymmetric structures and incorporate significant delays as a result of axonal propagation. Consequently, biologically inspired neural network models are more accurately described by nonlinear differential-delay equations rather than nonlinear ordinary differential equations (ODEs), and the standard techniques for studying the dynamics of RANNs are wholly inadequate for these models. This paper develops a ternary-logic based method for analyzing these networks. Key to the technique is the realization that a nonzero delay produces a bounded stability region. This result significantly simplifies the construction of sufficient conditions for characterizing the network equilibria. If the network gain is large enough, each equilibrium can be classified as either asymptotically stable or unstable. To illustrate the analysis technique, the swim central pattern generator (CPG) of the sea slug Tritonia diomedea is examined. For wide range of reasonable parameter values, the ternary analysis shows that none of the network equilibria are stable, and thus the network must oscillate. The results show that complex synaptic dynamics are not necessary for pattern generation.

  18. Kinetics of radiation-induced segregation in ternary alloys

    International Nuclear Information System (INIS)

    Lam, N.Q.; Kumar, A.; Wiedersich, H.

    1982-01-01

    Model calculations of radiation-induced segregation in ternary alloys have been performed, using a simple theory. The theoretical model describes the coupling between the fluxes of radiation-induced defects and alloying elements in an alloy A-B-C by partitioning the defect fluxes into those occurring via A-, B-, and C-atoms, and the atom fluxes into those taking place via vacancies and interstitials. The defect and atom fluxes can be expressed in terms of concentrations and concentration gradients of all the species present. With reasonable simplifications, the radiation-induced segregation problem can be cast into a system of four coupled partial-differential equations, which can be solved numerically for appropriate initial and boundary conditions. Model calculations have been performed for ternary solid solutions intended to be representative of Fe-Cr-Ni and Ni-Al-Si alloys under various irradiation conditions. The dependence of segregation on both the alloy properties and the irradiation variables, e.g., temperature and displacement rate, was calculated. The sample calculations are in good qualitative agreement with the general trends of radiation-induced segregation observed experimentally

  19. Microstructural Investigations On Ni-Ta-Al Ternary Alloys

    International Nuclear Information System (INIS)

    Negache, M.; Taibi, K.; Lounis, Z.; Souami, N.

    2010-01-01

    The Ni-Al-Ta ternary alloys in the Ni-rich part present complex microstructures. They are composed of multiple phases that are formed according to the nominal composition of the alloy, primary Ni(γ), Ni 3 Al(γ'), Ni 6 AlTa(τ 3 ), Ni 3 Ta(δ) or in equilibrium: two solid phases (γ'-τ 3 ), (τ 3 -δ), (τ 3 -γ), (γ-δ) or three solid phases (γ'-τ 3 -δ). The nature and the volume fraction of these phases give these alloys very interesting properties at high temperature, and this makes them attractive for specific applications. We have developed a series of ternary alloys in electric arc furnace, determining their solidification sequences using Differential Thermal Analysis (DTA), characterized by SEM-EDS, X-ray diffraction and by a microhardness tests. The follow-up results made it possible to make a correlation between the nature of the formed phases and their solidifying way into the Ni 75 Al x Ta y (x+y = 25at.%) system, which are varied and complex. In addition to the solid solution Ni (γ), the formed intermetallics compounds (γ', τ 3 and δ) has been identified and correlated with a complex balance between phases.We noticed that the hardness increases with the tantalum which has a hardening effect and though the compound Ni 3 Ta(δ) is the hardest. The below results provide a better understanding of the complex microstructure of these alloys.

  20. Face Liveness Detection Using Dynamic Local Ternary Pattern (DLTP

    Directory of Open Access Journals (Sweden)

    Sajida Parveen

    2016-05-01

    Full Text Available Face spoofing is considered to be one of the prominent threats to face recognition systems. However, in order to improve the security measures of such biometric systems against deliberate spoof attacks, liveness detection has received significant recent attention from researchers. For this purpose, analysis of facial skin texture properties becomes more popular because of its limited resource requirement and lower processing cost. The traditional method of skin analysis for liveness detection was to use Local Binary Pattern (LBP and its variants. LBP descriptors are effective, but they may exhibit certain limitations in near uniform patterns. Thus, in this paper, we demonstrate the effectiveness of Local Ternary Pattern (LTP as an alternative to LBP. In addition, we adopted Dynamic Local Ternary Pattern (DLTP, which eliminates the manual threshold setting in LTP by using Weber’s law. The proposed method was tested rigorously on four facial spoof databases: three are public domain databases and the other is the Universiti Putra Malaysia (UPM face spoof database, which was compiled through this study. The results obtained from the proposed DLTP texture descriptor attained optimum accuracy and clearly outperformed the reported LBP and LTP texture descriptors.