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  • 1
    ISSN: 1432-0630
    Keywords: 78.70.Bj ; 61.80 ; 72.80.Jc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The positron annihilation characteristics of the layered semiconductor InSe have been investigated. No evidence for low temperature positron trapping is found in as-grown and heavily deformed InSe. The temperature dependence of the S-parameter in these sample exhibits an increase rate in good agreement with the linear expansion coefficient along the c-axis. The positron lifetime spectra of electron-irradiated 0.01% Sn-doped InSe show a long-lifetime component of 336 ps which is tentatively attributed to positrons trapped at isolated In vacancies. Isochronal annealing experiments performed on these samples show that the recovery of the positron lifetime measured at 77K is accomplished in two stages. The first, starting after annealing at 150K, could be induced by the formation of complexes (VIn-SnIn). The second stage, observed at temperatures T≥375K, is attributed to the dissociation of these complexes and subsequent annealing of the In vacancies.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 105-110 (Jan. 1992), p. 961-964 
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Journal of Physics and Chemistry of Solids 39 (1978), S. 25-28 
    ISSN: 0022-3697
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 55 (1989), S. 2307-2309 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The time-resolved nonlinear transmission of bulk ε-GaSe has been studied in the femtosecond regime when resonantly exciting the material in the vicinity of the exciton at room temperature. Two regimes are evidenced. At early time delay, a blue shift of the exciton with no linewidth broadening can be related to optical Stark effect, while at longer time delay the usual exciton screening and band-gap renormalization due to real electronic transitions is observed. At resonance, a dependence of the Stark shift with the amplitude of the exciting field is obtained, as predicted by a simple "dressed-atom'' model.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 74 (1993), S. 3231-3237 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A systematic study of the electron transport and shallow impurity distribution in indium selenide above room temperature or after an annealing process is reported by means of far-infrared-absorption and Hall-effect measurements. Evidences are found for the existence of a large concentration of deep levels (1012–1013 cm−2), related to impurities adsorbed to stacking faults in this material. Above room temperature impurities can migrate from those defect zones and then become shallow in the bulk. The subsequent large increase of 3D electrons can change the dimensionality of the electron transport, which in most cases was 2D. The temperature dependence of the resistivity parallel to the c axis can be explained by the observed increase of the 3D electron concentration, whose motion across the layers is limited by stacking-fault-related potential barriers. The observed macroscopic resistivity is thus determined by tunneling through those barriers.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 79 (1996), S. 204-208 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Nitrogen doped gallium selenide single crystals are studied through Hall effect and photoluminescence measurements in the temperature ranges from 150 to 700 K and from 30 to 45 K, respectively. The doping effect of nitrogen is established and room temperature resistivities as low as 20 Ω cm are measured. The temperature dependence of the hole concentration can be explained through a single acceptor-single donor model, the acceptor ionization energy being 210 meV, with a very low compensation rate. The high quality of nitrogen doped GaSe single crystals is confirmed by photoluminescence spectra exhibiting only exciton related peaks. Two phonon scattering mechanisms must be considered in order to give quantitative account of the temperature dependence of the hole mobility: scattering by 16.7 meV A′1 homopolar optical phonons with a hole-phonon coupling constant g2=0.115 and scattering by 31.5 meV LO polar phonon with a hole Fröhlich constant αh⊥=0.741. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 71 (1992), S. 3256-3259 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have investigated the molecular beam homoepitaxial and heteroepitaxial growth of InSe and GaSe III–VI compounds semiconductors. In situ reflection high-electron energy diffraction measurements reveal that two-dimensional epitaxial growth occurs on (00.1) oriented substrates, at substrate temperatures ranging from 300 to 350 °C. A scanning electron microscopy study of the films surfaces has been performed to correlate their morphology to the growth conditions.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 62 (1987), S. 1477-1483 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Conditions for efficiency improvement and optimization in indium-tin-oxide/p-indium-selenide solar cells are discussed in this paper. This aim is achieved by using low-resistivity p-indium-selenide and by incorporating a back-surface-field contact. This contact is insured by a p-indium selenide/gold barrier whose rectifying behavior is explained through the complex impurity structure of p-indium-selenide. Electrical and photovoltaic properties of the cells are also reported. The efficiency parameters under AM1 simulated conditions have been improved up to 32 mA/cm2 for the short-circuit current density, 0.58 V for the open-circuit voltage, and 0.63 for the filling factor. As a result, solar efficiencies larger than 10% in annealed cells and 8% in unannealed ones have been attained. The limitations of these devices are discussed by investigating the dependence of electrical and efficiency parameters in function of photon flux and temperature.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 60 (1986), S. 3282-3288 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The optical absorption edge of Zn3P2 has been measured by transmittance and photoconductivity at 300 K. The absorption coefficient in both polarizations is shown to follow the expected behavior for indirect gaps at 1.39 and 1.41 eV in parallel and perpendicular configurations. The high-absorption region has been measured in thin single crystals and the absorption coefficient is shown to agree with the optical constants derived from reflectivity for values of the absorption coefficient up to 105 cm−1. The optical properties and the behavior of photoconductivity are discussed in view of possible applications of Zn3P2 to solar energy conversion.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 61 (1987), S. 5267-5271 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Two-dimensional precipitates associated with stacking faults in layer semiconductors have previously been put forward to explain transport properties of these crystals, especially their remarkable electrical anisotropy. High-field cyclotron resonance behavior, among others, can be accounted for by two-dimensional accumulation layers in the vicinity of these defects. Direct evidence for the existence of these defects has been obtained by electron microscopy and x-ray microprobe analysis in indium selenide. Planar faults act like sinks for impurity atoms. This accounts for the unique behavior of layer compounds which exhibit intrinsic behavior (low apparent carrier concentration—high mobilities) even with high (100 ppm) initial doping levels. Optical, transport, and magnetotransport properties at low temperature can be explained along this model. As regards the applications of indium selenide to the photovoltaic conversion of solar energy, the existence of these defects explains most features of this semiconductor in this respect: (i) Its comparatively low effective diffusion length parallel to the c axis. (ii) p- to n-type switching under thermal annealing which allows fabrication of p-n junctions. (iii) Low apparent carrier density which precludes abrupt profiles for p-n structures.
    Type of Medium: Electronic Resource
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