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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 74 (1993), S. 5757-5760 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The surface versus bulk composition and electronic structure of polycrystalline CuInSe2 thin-film interfaces were studied by synchrotron radiation soft-x-ray photoemission spectroscopy. An n-type In2Se3/CuIn3Se5 surface layer forms on enhanced-grain polycrystalline thin-film p-type CuInSe2 during fabrication. Enhanced-grain CuInSe2 films were sputter etched (500 V Ar) and analyzed in situ to determine core-level binding energies and Fermi-level positions for the n-type surface and the p-type CuInSe2 bulk within ±0.1 eV. The transition between the n-type surface and the p-type bulk was experimentally observed by noting the change in the position of the valence-band maximum relative to the Fermi level EF. From these measurements, the valence-band offset ΔEv between the layers was determined to be 0.50 eV. Measurement of the work functions φ was also completed and reveals φ=4.75 eV for the In2Se3 (CuIn3Se5) surface layer and φ=4.04 eV for the bulk CuInSe2. Combining these results allows construction of a surface band diagram for this device configuration as well as determination of the relationship between composition, electronic structure, and device performance.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 70 (1991), S. 3857-3861 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Rapid isothermal processing (RIP) based on incoherent sources of light is emerging as a reduced thermal budget (product of processing time and temperature) processing technique. As compared to stand alone annealing unit, the in situ RIP unit is very attractive for the next generation of devices. A number of unwanted physical phenomena can be suppressed or completely eliminated in the in situ RIP case leading to improved quality of materials when compared to their ex situ rapid isothermal annealed and furnace annealed counterparts. We have used in situ rapid isothermal processor for the in situ rapid isothermal chemical cleaning of InP and GaAs substrates and in situ metallization of InP and GaAs Schottky diodes. As compared to ex situ annealing, the negligible oxygen content at the surface and interface of in situ RIP samples result in better current-voltage characteristics, lower and compressive stress values, as well as smooth and continuous morphologies of the ohmic contact. In this paper, we have highlighted the role of in situ RIP in the metallization of InP and GaAs devices.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We describe a new method of processing Tl-Ba-Ca-Cu-O (TBCCO) superconducting thin films. In this method, two identical elemental multilayer films containing Tl layers were prepared using an electron-beam deposition technique. The thin-film samples were then placed in face-to-face contact in a quartz crucible and heat treated at 740 °C for 10 min in flowing air. The x-ray microanalysis of the bottom sample indicates promising results for obtaining the desired chemical composition. Random characterization from different sections of the sample showed that the microanalysis values had less scatter than those for samples prepared using the usual bulk postdeposition method. The average chemical composition of the 13 points obtained from the random section is Tl1.8Ba1.8Ca1.9Cu2.0Ox. However, oxygen analysis showed that the concentration of oxygen is low and poorly distributed, presumeably attributable to the low oxygen flow. This method has several advantages over the conventional Tl-O vapor processing using pure metallic thallium, thallium oxide or bulk TBCCO. These advantages include: (a) increase in uniformity of thallium deposition, (b) safer processing as a result of a smaller release of thallium, and (c) reduction of processing cost.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 76 (2000), S. 1443-1445 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report the epitaxial growth of zinc-blende BxGa1−x−yInyAs and BxGa1−xAs on GaAs substrates with boron concentrations (x) up to 2%–4% by atmospheric-pressure metalorganic chemical vapor deposition. The band gap of BxGa1−xAs increases by only 4–8 meV/%B with increasing boron concentration in this concentration range. We demonstrate an epitaxial BxGa1−x−yInyAs layer deposited on GaAs with a band gap of 1.34 eV that is significantly less strained than a corresponding Ga1−yInyAs layer with the same band gap. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Contact surface resistivities (product of contact resistance and area) in the 10−10 Ω cm2 range have been obtained for both silver and gold contacts to high Tc superconductors. This is a reduction by about eight orders of magnitude from the contact resistivity of indium solder connections. The contact resistivity is low enough to be considered for both on-chip and package interconnect applications. The contacts were formed by sputter depositing either silver or gold at low temperatures (〈100 °C) on a clean surface of Y1 Ba2 Cu3 O7−δ (YBCO) and later annealing the contacts in oxygen. Annealing temperature characteristics show that for bulk-sintered YBCO samples there is a sharp decrease in contact resistivity after annealing silver/YBCO contacts in oxygen for 1 h at temperatures above ∼500 °C and gold/YBCO contacts for 1 h above ∼600 °C. Oxygen annealing for longer times (8 h) did not reduce the contact resistivity of silver contacts as much as annealing for 1 h. Auger microprobe analysis shows that indium/YBCO contacts contain a significant concentration of oxygen in the indium layer adjacent to the YBCO interface. Silver and gold contacts, on the other hand, contain almost no oxygen and have favorable interfacial chemistry with low oxygen affinity. Silver also acts as a "switchable'' passivation buffer, allowing oxygen to penetrate to the YBCO interface at elevated temperatures, but protecting the YBCO surface at room temperature.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 57 (1990), S. 1239-1241 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The measurement of thermal stress of SrF2 films on InP as a function of temperature is presented. The in situ and ex situ rapid isothermal annealed films have different values of thermal stress at room temperature and show entirely different behavior of thermal stress during heating and cooling cycles. X-ray photoelectron spectroscopy measurements were used to characterize the surface of the SrF2 films as well as the SrF2/InP interface for both the ex situ and in situ annealed films. It is shown that the difference in the microstructure of in situ and ex situ rapid isothermal annealed SrF2 films on InP is indeed reflected in the significant difference in the thermal stress.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Surface and Interface Analysis 15 (1990), S. 159-162 
    ISSN: 0142-2421
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: An ionized cluster beam (ICB) source was used to deposit A1 onto two types of silicon oxides. One was a thermal oxide generated by steam oxidation of Si at 900°C. The other was a P-doped oxide deposited on Si at 425°C. During Al deposition, 60 μm diameter wires were held at the substrates to serve as masks. After A1 deposition, the wires were removed and the masked areas were examined by scanning electron microscopy (SEM) and by scanning Auger microprobe (SAM). The ICB source was operated at 0, 3 and 6 kV accleration voltages. The substrates were held at 80, 200 and 400°C during A1 depositions. The A1 deposition rate averaged 24 nm min.-1 The chamber pressure during deposition was 3 × 10-4 Pa. The diffusion distance of A1l under a mask edge was determined from the SEM micrographs and SAM line scans. The maximum diffusion distance occurred at 200°C for both substrates, with the exception of the 0 kV A1 beam deposited on the low-temperature oxide (LTO). On the high-temperature oxide (HTO), the maximum diffusion distance was 29 μm at 6 kV acceleration voltage. The minimum diffusion distance was 8 μm at 70-80°C on the LTO for acceleration voltages of 0 and 3 kV.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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