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  • 1
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 80 (1996), S. 3017-3023 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Comparative electroluminescence and photoluminescence measurements were performed on Si/Si0.7Ge0.3 p-i-n single quantum well structures, and on one p-i-n and one undoped multiple quantum well structure in a wide temperature range. The samples were grown pseudomorphically by molecular beam epitaxy, and mesa diodes for electroluminescence and photocurrent measurements were fabricated. In electroluminescence, optical emission comes primarily from the SiGe quantum wells whereas no emission from Si is observed except for high temperatures of ≈200 K and up. All p-i-n structures exhibit maximum emission intensities in a temperature range between 80 K and 220 K, depending on the quantum well width. This temperature characteristic is very different from undoped quantum well samples. A model is discussed that accounts satisfactorily for all observed temperature dependent data. As an essential feature, the model includes Auger recombination in addition to radiative recombination in the n+ and p+ sides of the junctions and in the SiGe quantum well due to the high electron or hole densities in these regions. Photocurrent spectra due to single quantum wells are measured showing the SiGe absorption threshold in addition to the Si threshold. Quantitative fits to these spectra yield threshold energies for SiGe and Si consistent with the electroluminescence spectra. The question of how photogenerated excess holes that are bound in a quantum well can escape the well at 4.2 K to yield the measured photocurrents is discussed. © 1996 American Institute of Physics.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 78 (1995), S. 5013-5021 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: A theory has been developed describing x-ray diffuse scattering from misfit dislocations in epitaxial layers. This approach has been used for explaining the origins of diffuse x-ray scattering from SiGe layers with linearly graded Ge content. The distribution of the diffusely scattered intensity in reciprocal plane measured by triple-axis x-ray diffractometry has been compared with theoretical predictions and a good agreement has been achieved. It is demonstrated that the main part of the diffusely scattered intensity originates from random strains caused by misfit dislocations at the substrate–epilayer interface or in the relaxed part of the compositionally graded layers. The contribution of the threading dislocation segments to the diffuse scattering is rather small. © 1995 American Institute of Physics.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 54 (1989), S. 819-821 
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: (100) silicon molecular beam epitaxy films with etch pit densities below 103 cm−2 and χmin values of 3.3–3.9% were grown at very low temperatures (Ts =250–350 °C). Although dopant activation is significantly below unity at n=1018 Sb atoms/cm3 Hall mobilities of homogeneously Sb-doped samples (Ts =250 °C, 300 °C) are found to match reasonably bulk values. δ doping at a monolayer Sb deposition shows a dopant activation of 0.45–0.81 with no detectable broadening at Ts =200 °C.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 60 (1986), S. 1735-1739 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: In spreading resistance analysis, which is a method usually employed in doping profiling, carrier spilling effects become evident in doping structures in the 0.1-μm range. Profiles from spreading resistance analysis with such thin layers are to be interpreted rather in terms of "on bevel'' carrier distribution than as actual doping profiles. Due to specific boundary conditions introduced by beveling, carrier spilling decisively depends on whether high-low or low-high transitions are considered. Using sample mounting both in standard and in upside down configuration high resolution of high-low as well as low-high transition is achieved.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 67 (1995), S. 223-225 
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: High-resolution x-ray reciprocal space mapping was employed to determine the in-depth strain distribution of Si1−xGex films with linear composition gradings between 4.2% and 15% Ge per μm, and thicknesses between 0.4 and 1.7 μm. The variation of grading and thickness parameters of the samples provides a complete picture of the overall relaxation behavior of linearly graded epilayers. The x-ray data show a top layer of grading-dependent residual strain whereas the lower parts of the films are completely and/or partly relaxed with respect to the Si substrate. © 1995 American Institute of Physics.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 63 (1993), S. 376-378 
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: A variety of SiGe quantum well (QW) samples were grown by solid-source molecular beam epitaxy (MBE) to study the influence of growth temperature TG and QW width Lz on the photoluminescence (PL) properties. For all growth temperatures investigated (350 °C≤TG≤750 °C) we found intense, well-resolved PL signals from the SiGe QWs. The PL intensity increases with TG, and the stability against measurement temperature becomes better. A formerly reported PL band below the SiGe band edge is either completely absent, or very weak in the 4.2 K spectra of our samples. Thus, the defects or complexes responsible for this signal are obviously not inherent properties of MBE growth.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 60 (1992), S. 1729-1731 
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Ultrametastable silicon-germanium (Si1−xGex) layers with a Ge content x in the range from about 20% to 27% were grown by Si-MBE at temperatures far below 550 °C (325–450 °C). The thicknesses of the layers (up to 500 nm) exceed the equilibrium thickness by a factor of up to 50. We observe in the as-grown samples without any annealing both the excitonic Si1−xGex band-edge luminescence and a broad alloy luminescence of unknown origin. The two peaks have an energy difference of ≈144 meV and shift linearly with the Ge content. The alloy band luminescence disappears when strain relaxation sets on upon annealing at around 600 °C.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 8
    Digitale Medien
    Digitale Medien
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Environment and Resources 21 (1996), S. 145-166 
    ISSN: 1056-3466
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Energietechnik
    Notizen: Abstract Increases in greenhouse gas emissions and concerns about potential global climate change are stimulating worldwide interest in the feasibility of capture, disposal, and utilization of CO2 from large energy systems. Technology to capture CO2 from power plant flue gas, while energy intensive and expensive, is commercially available. Capture from advanced combustion systems offers a further opportunity to significantly reduce cost and energy requirements of CO2 capture compared to that from today's pulverized coal power plants. No viable disposal options exist today for large quantities of captured CO2. Ocean disposal of CO2 and geological storage, especially in depleted oil and gas wells, are leading candidates. Although some niche utilization may occur, utilization seems unlikely to become a major sequestration option. Since CO2 capture and sequestration is a relatively expensive mitigation option, it can be regarded as an insurance policy. However, since CO2 mitigation options are few in number, continued research to reduce the costs of CO2 capture and to develop feasible sequestration options is important.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    Amsterdam : Elsevier
    Journal of Crystal Growth 81 (1987), S. 440-444 
    ISSN: 0022-0248
    Quelle: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Thema: Chemie und Pharmazie , Geologie und Paläontologie , Physik
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 10
    Digitale Medien
    Digitale Medien
    Amsterdam : Elsevier
    Journal of Crystal Growth 95 (1989), S. 484-485 
    ISSN: 0022-0248
    Quelle: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Thema: Chemie und Pharmazie , Geologie und Paläontologie , Physik
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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