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  • 1
    Electronic Resource
    Electronic Resource
    Oxidation studies on .beta.-lactam antibiotics. The 6-(diacylamino)penicillins (1986)
    s.l. : American Chemical Society
    The @journal of organic chemistry 51 (1986), S. 1811-1815 
    Details
    ISSN: 1520-6904
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/jo00360a030
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  • 2
    Electronic Resource
    Electronic Resource
    Theoretical study of time-resolved Raman scattering profiles of hot electrons in semiconductors (1992)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 72 (1992), S. 4325-4335 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A comprehensive time-resolved electronic Raman scattering theory for nonequilibrium carrier excitations in semiconductors is presented. The following are simultaneously taken into account: (i) the effects of the ultrashort laser pulse for probing the excited carrier distribution function; (ii) the fact that the fluctuation-dissipation theorem is not valid under conditions of nonequilibrium carrier distributions; (iii) the effects of quasiparticle life time via a finite collision time in the Raman scattering cross section; and (iv) the effect of the time-dependent resonant enhancement factor due to the band structure. The single-particle scattering spectra for spin-density fluctuation contribution is found to be significantly broadened by an ultrashort laser pulse, but is substantially narrowed by the finite collision time. The effect of the time-dependent resonant enhancement factor has been demonstrated to broaden the line shape of single-particle scattering spectra for the spin-density fluctuation contribution as the probe photon energy increases.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.352196
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  • 3
    Electronic Resource
    Electronic Resource
    Analysis of the single-particle scattering spectra for spin-density fluctuations of electrons in n-GaAs at T=300 K (1993)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 73 (1993), S. 3023-3027 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The line shapes of single-particle scattering spectra for spin-density fluctuations of electrons in n-GaAs with carrier concentrations ranging from 5×1015 to 7×1017 cm−3 have been analyzed. We have found that the Raman line shapes can be very well explained by a theory developed by Hamilton and McWhorter which takes into account both the band-structure effects in semiconductors and the effects of carrier collision in a relaxation time approximation. For carrier concentration n≥2×1016 cm−3, the effects of finite collision time has been demonstrated to be very important and these effects must be properly taken into account in order to satisfactorily interpret the line shapes of single-particle scattering spectra for spin-density fluctuations in n-GaAs at T=300 K. We show that although Lindhard–Mermin's expression for dielectric constant as well as Hamilton and McWhorter's theory fit the Raman line shapes equally well for carrier density n=7×1017 cm−3, neglect of band-structure effects of the former tends to underestimate the carrier collision time. An interpretation of the deduced collision time in terms of electron-electron, electron-impurity, and electron-phonon scattering is also given.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.353008
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  • 4
    Electronic Resource
    Electronic Resource
    Avalanche multiplication in submicron AlxGa1−xAs/GaAs multilayer structures (2000)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 88 (2000), S. 2601-2608 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A systematic study of the role of band edge discontinuities on ionization rates in periodic AlxGa1−xAs/GaAs structures has been performed by measuring the electron and hole multiplication characteristics in a series of submicron AlxGa1−xAs/GaAs multilayer p–i–n and n–i–p structures. These structures comprise alternating 500Å AlxGa1−xAs and GaAs layers in the intrinsic multiplication regions, with a total thickness of up to 0.5 μm. The results show little dependence on initiating carrier type for multiplication region widths above 0.3 μm, nor on whether they originate in GaAs or AlxGa1−xAs. Only alloy-like behavior is observed at all values of multiplication up to the breakdown voltage in contrast to earlier work on single heterojunction structures where a large difference was seen at low values of multiplication between carriers starting in GaAs and AlxGa1−xAs. The microscopic aspects of hot carrier transport in these devices were studied numerically using a simple Monte Carlo model. Simulations suggest that the energy gained from the conduction band edge discontinuity from AlxGa1−xAs to GaAs is offset by the increased energy loss via the higher phonon scattering rate in the preceding AlxGa1−xAs layer. We conclude that AlxGa1−xAs/GaAs multilayer structures offer no electron ionization enhancement. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1286329
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  • 5
    Electronic Resource
    Electronic Resource
    Impact ionization in AlxGa1−xAs/GaAs single heterostructures (1998)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 84 (1998), S. 4363-4369 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Impact ionization involving transport across a single heterojunction has been studied by measuring the electron and hole initiated multiplication, Me and Mh, in a series of p+in+ AlxGa1−xAs(500 Å)/GaAs(500 Å) heterostructures with x ranging from 0.3 to 0.6. At low electric fields, because of dead space effects, Me and Mh in these devices are very different and are primarily determined by the ionization properties of the material in the latter half of the structure. As the electric field increases, feedback from the opposite carrier type causes Me and Mh to converge to the values measured in the equivalent alloy. The effects of the band-edge discontinuities at the heterojunction interface on Me and Mh in these heterostructures are compensated by the different energy-loss rates in AlxGa1−xAs and GaAs. A simple Monte Carlo model using effective conduction and valence bands is used to interpret the experimental results. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.368656
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  • 6
    Electronic Resource
    Electronic Resource
    The Diffusion Coefficient of Calcium Chloride in Aqueous Solution at 25° (1952)
    s.l. : American Chemical Society
    Journal of the American Chemical Society 74 (1952), S. 2776-2777 
    Details
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ja01131a021
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  • 7
    Electronic Resource
    Electronic Resource
    Well-width dependence of radiative and nonradiative recombination times in ZnO/Mg0.12Zn0.88O multiple quantum wells (2001)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 90 (2001), S. 3650-3652 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A set of ZnO/Mg0.12Zn0.88O multiple quantum wells (MQWs) with well widths, Lw, varying from 6.91 to 46.5 Å has been grown by laser molecular-beam epitaxy. We estimated the Lw dependence of the radiative and nonradiative recombination times of localized excitons at 5 K. Suppression of quantum efficiency can be avoided even in the MQWs having small Lws studied in this work. Effects of excitonic localization are discussed in order to explain the Lw dependence of radiative recombination time at 5 K. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1396827
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  • 8
    Electronic Resource
    Electronic Resource
    Picosecond Raman studies of electric-field-induced nonequilibrium carrier distributions in GaAs-based p-i-n nanostructure semiconductors (1994)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 64 (1994), S. 1230-1232 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Electron transport in GaAs-based p-i-n nanostructure semiconductors under the application of an electric field has been studied by transient Raman spectroscopy on a picosecond time scale and at T(approximately-equal-to)80 K. For an injected carrier density of n(approximately-equal-to)2.2×1018 cm−3 and electric field intensity E=25 kV/cm, the drift velocity of electrons as high as Vd=2.5×107 cm/s was observed. These experimental results are in good agreement with Ensemble Monte Carlo calculations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.110848
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  • 9
    Electronic Resource
    Electronic Resource
    Electron multiplication in AlxGa1−xAs/GaAs heterostructures (1997)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 71 (1997), S. 3877-3879 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have measured the electron multiplication characteristics of thin (∼0.1 μm) AlxGa1−xAs(500 Å)/GaAs(500 Å) single heterostructures with 0.3≤x≤0.6, grown in a p-i-n configuration. In these devices, at low electric fields, the electron multiplication occurs mainly in the latter half of the i region because of dead space effects. As the electric field increases the multiplication behavior converges to that of the equivalent alloy. Our measurements show that the electron multiplication in these structures never exceeds that of GaAs. A simple Monte Carlo simulation suggests that the advantage obtained from the conduction band edge step down from AlxGa1−xAs to GaAs is offset by the energy loss via higher phonon emission in the AlxGa1−xAs layer. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.120531
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  • 10
    Electronic Resource
    Electronic Resource
    Temperature dependence of near ultraviolet photoluminescence in ZnO/(Mg, Zn)O multiple quantum wells (2001)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 78 (2001), S. 1979-1981 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report on temperature dependence of excitonic photoluminescence (PL) from ZnO/(Mg, Zn)O multiple quantum wells (MQWs). Two kinds of MQWs having different barrier heights grown by laser molecular-beam epitaxy showed significantly different temperature dependences of PL spectra; in ZnO/Mg0.27Zn0.73O MQWs, the PL peak energy at 50–200 K was a monotonically increasing function of temperature, which was opposite to that ascribed by band gap shrinkage. Moreover, spectra taken at 95–200 K encompassed two peaks, both of which originated from recombination of localized excitons. The temperature-induced shift (redshift-blueshift-peak duplication-redshift) at 5–300 K is caused by a change in the exciton dynamics with increasing temperature due to inhomogeneity and the exciton localization effect. On the other hand, the corresponding dependence in ZnO/Mg0.12Zn0.88O MQWs (lower barrier height) was similar to that in bulk II–VI semiconductors. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1357451
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