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  • 1
    Electronic Resource
    Electronic Resource
    Radiation of acoustic phonons from quantum wires (1995)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 77 (1995), S. 5095-5097 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have investigated by the Monte Carlo technique the radiation of ballistic acoustic phonons from quasi-one-dimensional electron gas in quantum wires. At low temperatures and over a wide range of electric fields, all excess heat in quantum wires is dissipated by means of acoustic phonons. Due to the uncertainty of momentum conservation during electron–acoustic-phonon scattering, electrons emit acoustic phonons with large transverse momentum components. Consequently, in this transport regime quantum wires radiate fluxes of nonequilibrium acoustic phonons into surrounding material. Nonequilibrium acoustic phonons can propagate ballistically over macroscopic distances. Ballistic fluxes of nonequilibrium acoustic phonons have been previously detected experimentally in quantum well structures. We have calculated the angular and energy spectrum of nonequilibrium acoustic phonons radiated from quantum wires. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.359318
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  • 2
    Electronic Resource
    Electronic Resource
    Hot-electron relaxation dynamics in quantum wires (1994)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 76 (1994), S. 1021-1028 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Monte Carlo simulations of hot nonequilibrium electron relaxation in rectangular GaAs quantum wires of different cross sections are carried out. The simulations demonstrate that the initial stage of hot-electron cooling dynamics is determined by cascade emission of optical phonons and exhibits strong dependence on the excitation energy. The second (slow) relaxation stage is controlled by strongly inelastic electron interactions with acoustic phonons as well as by nonequilibrium (hot) optical phonons. The relaxation times obtained in our simulations are in good agreement with the results of recent luminescence experiments. At low electron concentrations where hot phonon effects are negligible the cascade emission of optical phonons may lead to the overcooling of the electron system to temperature below the lattice temperature. These electrons then slowly (during tens of picoseconds) relax to equilibrium due to the interaction with acoustic phonons. At certain excitation energies strong intersubband electron scattering by optical phonons leads to electron redistribution among subbands and intersubband population inversions. If the electron concentration exceeds 105 cm−1, hot phonon effects come into play. In contrast to bulk materials and quantum wells, hot phonon effects in quantum wires exhibit strong dependence on the initial broadening of the energy distribution of the electrons. The very initial electron gas relaxation stage in quantum wires is faster in the presence of hot phonons, while for t(approximately-greater-than)0.5 ps the hot phonon thermalization time defines the characteristic electron cooling time.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.357889
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Size dependence of the thermal broadening of the exciton linewidth in GaAs/Ga0.7Al0.3As single quantum wells (1992)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 61 (1992), S. 1411-1413 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have studied the temperature dependence of the linewidth, Γ(T), of the fundamental absorption edge in bulk GaAs and four GaAs/Ga0.7Al0.3As single quantum wells of different well width using photoreflectance. As a result of the size dependence of the exciton-longitudinal optical phonon interaction, the thermal broadening of the linewidth diminishes as the dimensionality and size of the system are reduced.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.107554
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  • 4
    Electronic Resource
    Electronic Resource
    Transition from longitudinal-optical phonon scattering to surface-optical phonon scattering in polar semiconductor superlattices (1991)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 59 (1991), S. 1093-1095 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Dielectric continuum models of optical-phonon modes predict an enhancement in the strength of the surface-optical (SO) modes in double-barrier heterostructures as the heterojunction-to-heterojunction separation is reduced. There is currently no consensus on the nature of the electron-SO-phonon coupling interaction. In this work, the ratio of electron scattering by the SO-phonon modes to that by the confined longitudinal-optical (LO) phonon modes is calculated for a GaAs/AlAs short-period superlattice based on the assumption that the electron-SO-phonon interaction may be described by a scalar potential. The scaling of the ratio of electron-SO-phonon scattering to electron-LO-phonon scattering as a function of the superlattice period provides a sensitive test of the appropriateness of the scalar-potential model.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.106354
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