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  • 1
    Electronic Resource
    Electronic Resource
    Influence of compensation on 77 K free carrier absorption in n-ZnS (1992)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 72 (1992), S. 1648-1650 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Quantum theory is applied to calculate the free carrier absorption coefficients in n-ZnS. This treatment includes all major scattering mechanisms and screening. We present the results of calculations of 77 K free carrier absorption and derivative logarithmic absorption coefficients, as a function of the free carrier concentration and compensation ratio, at 10 μm. We discuss the unambiguous determination of both free carrier concentration and compensation ratio for unknown samples.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.351684
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  • 2
    Electronic Resource
    Electronic Resource
    Electron transport in ZnS (1990)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 68 (1990), S. 1714-1719 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Transport characteristics of N-ZnS are calculated by solving the Boltzmann transport equation using a variational method (including all major scattering mechanisms and screening). The dependence of electron mobility on carrier concentration, for a range of compensation ratio and ionized impurity concentration, are given at both 300 and 77 K. This provides a rapid means for determining material quality. Mobility limits of 230 cm2/V s (n∼1019 cm−3) and over 3000 cm2/V s (n〈1014 cm−3) are calculated at 300 and 77 K, respectively. The temperature dependence of the mobility is calculated and agrees favorably with experimental data.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.346599
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  • 3
    Electronic Resource
    Electronic Resource
    Multiqubit computing and error-avoiding codes in subspace using quantum dots (2002)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 91 (2002), S. 2524-2529 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: An approach is presented for directly constructing cn-Not multi-qubit logic gates using quantum dots. In addition, error-avoiding codes in the projected subspace are discussed, offering a potentially robust scheme for protecting against decoherence. The following general conditions were found: (1) a projected subspace can always be constructed, in which decoherence effects can be cancelled by adjusting the interaction coupling time, enabling error-correction to be performed. This subspace is closed for the projected states. (2) The necessary and sufficient conditions for a decoherence-free subspace are that the second term in the subdynamic equation, be equal to zero. Commonly formulated conditions for a decoherence-free subspace are shown to be particular approximations of this condition, including the so-called Born–Markovian approximation. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1436289
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  • 4
    Electronic Resource
    Electronic Resource
    A generalized approach to surface photovoltage (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 79 (1996), S. 7790-7799 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A detailed majority and minority carrier current balance model for surface photovoltage (SPV) is presented. A rigorous treatment of carrier junction generation and surface recombination is shown to be essential. We show that under weak above band gap photoexcitation, standard constant open-circuit voltage and constant photon flux SPV measurements can both reveal the bulk minority carrier diffusion length, provided the initial band bending Vbi is sufficiently high. However, when Vbi is small, approximate SPV expressions are inapplicable and both standard SPV manifestations will then yield incorrect diffusion length values. We also show that for cases of low surface recombination velocity, the SPV technique can be used to measure the width of the space charge region and Vbi; however, when the surface recombination velocity is large, this approach cannot be used as majority carrier backdiffusion can play a dominant role under high photon energy excitation conditions. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.362386
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  • 5
    Electronic Resource
    Electronic Resource
    Influence of temperature on magnetism in a quantum confined system (2000)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 87 (2000), S. 2520-2525 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: In this article, we present new formulas to describe the relation between temperature and average spin in a quantum confined system by using a Green's function approach. We focus on a lattice of quantum dots, each of which confines several electrons on the sites of the confined crystal lattice under the influence of an external magnetic field. Our treatment makes use of the Heisenberg model, subject to a transverse magnetic field. We show that at low temperatures, the temperature dependence of magnetic moment differs from a 3/2 power law, and present a unique signature for temperatures approaching or beyond the phase transition temperature. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.372213
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  • 6
    Electronic Resource
    Electronic Resource
    Theoretical study of hole transport in ZnSe (1986)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 59 (1986), S. 3516-3526 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Hole mobilities in ZnSe were calculated by solving the Boltzmann transport equation by the variational method, with all major scattering mechanisms included. Valence-band state symmetries were accounted for, both intra- and interband scattering terms for light and heavy holes were included, and generalized Fermi–Dirac statistics were used throughout. Screening of polar optical phonon and ionized impurity scatterings was also included. The contributions of all component scattering mechanisms to the total hole mobility as a function of hole concentration at 300 and 77 K, have been calculated for the first time. The influence of the compensation ratio, and the concentration of ionized impurities on both the hole mobility and resistivity has also been calculated for the first time; these results are shown to facilitate rapid and direct evaluation of electronic materials quality. In addition, the theoretical model was used to calculate the temperature dependence of the hole mobility in ZnSe, which proved to be in excellent agreement with available experimental data, confirming the choice of scattering parameters. Ultimate limits for the hole mobility in ZnSe at 300 and 77 K were calculated to be about 110 and 2000 cm2/V s, respectively, given zero compensation. Finally a derivation of the heavy-hole effective mass in ZnSe is presented, which yields a value 0.60 m0.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.337041
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  • 7
    Electronic Resource
    Electronic Resource
    Application of free-carrier absorption to N-ZnSe materials characterization (1987)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 61 (1987), S. 3035-3043 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Quantum theory has been applied to calculations of free-carrier absorption in N-ZnSe (including all major scattering mechanisms and screening). The electron concentration n, dependence of the free-carrier absorption coefficient α, was calculated as a function of the ionized impurity concentration and the compensation ratio θ. An inherent limit to α, αinh, was determined at photon wavelengths, λ, of 3.3, 5, and 10 μm. At 10 μm, log αinh (cm−1)(approximately-equal-to)log n (cm−3)−15.9 for 1014(approximately-less-than)n (cm−3)(approximately-less-than)1017. A second experimental parameter, the derivative logarithmic absorption coefficient p, is shown to provide an unambiguous method for uniquely determining n and θ, when used in conjunction with α||λ. The relation of n (cm−3)(approximately-equal-to)6.7×1015 (3.5 −p) α (cm−1) is proposed for λ=10 μm. Experimental data from the literature are analyzed in this scheme and values of n determined by Hall-effect measurements are shown to be in excellent agreement with theoretical predictions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.337855
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  • 8
    Electronic Resource
    Electronic Resource
    A theoretical analysis of electron transport in ZnSe (1986)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 59 (1986), S. 1220-1231 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Boltzmann's transport equation was solved using a variational method (including all major scattering mechanisms and screening) yielding electron mobilities in n-ZnSe. The electron concentration dependence of the mobility at 300 and 77 K was calculated as functions of ionized impurity concentration and compensation ratio. A routine method for determining acceptor and donor densities (total and ionized) and compensation ratio from given experimental mobility and carrier concentration values is outlined; mobilities reported for samples grown by various techniques are discussed. Inherent limits to the mobility are given as about 800 cm2/V s (n∼3×1018 cm−3) and about 1×104 cm2/V s (n≤4×1015 cm−3) at 300 and 77 K, respectively. The calculated temperature dependence of the mobility for η=−6 is used to explain qualitative trends in such behavior for material grown by different techniques, and to provide an inherent mobility limit at this η.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.336509
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  • 9
    Electronic Resource
    Electronic Resource
    Passivation of GaAs(111)A surface by Cl termination (1995)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 67 (1995), S. 670-672 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: It is found that an ordered and air-stable GaAs(111)A–(1×1)–Cl surface can be produced by chemical etching/passivation with dilute HCl solution. The synchrotron polarization-dependent Cl K-edge x-ray absorption near-edge structure and x-ray photoelectron spectroscopy studies showed that the surface is terminated with Ga–Cl bonds oriented along the surface normal. Low-energy electron diffraction studies showed a bulklike (1×1) structure on the Cl-terminated GaAs(111)A surface. The Cl termination eliminates surface band-gap states caused by surface oxides. Photoluminescence measurements showed a dramatic increase in the near-band radiative emission rate corresponding to reduction in the occupied surface band-gap states. A reduction of surface gap states by Cl termination was confirmed by surface photovoltage measurements. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.115198
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  • 10
    Electronic Resource
    Electronic Resource
    Molecular-beam epitaxial growth of GaAs and InGaAs/GaAs nanodot arrays using anodic Al2O3 nanohole array template masks (2002)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 81 (2002), S. 361-363 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Highly ordered arrays of nanosized GaAs-based dots were successfully prepared on GaAs (001) substrates by molecular-beam epitaxy using selected area growth. Selected area growth employed alumina nanochannel array (NCA) templates formed by anodic oxidation, bonded to the GaAs substrates. Homogeneous GaAs dots, as well as compositionally modulated heterostructures within the nanosized dots, were demonstrated. In the latter case, multilayer InGaAs/GaAs heterostructured nanodot arrays were fabricated. Dot growth occurred only as defined by the template mask, resulting in a hexagonal lattice of dots with 100 nm period spacing, with dots retaining the circular lateral shape of the pores as determined by the NCA template pore size; dot diameters were adjustable from 45 to 85 nm for a lattice period of 100 nm. Cathodoluminescence spectra from an InGaAs/GaAs 10×10 dot array clearly showed an emission peak at 920 nm (5 K), confirming the formation of a high-quality InGaAs/GaAs quantum dot array. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1484554
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