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G. G. Zegrya - One of the best experts on this subject based on the ideXlab platform.

  • Theoretical study of Auger Recombination processes in deep quantum wells
    Semiconductors, 2008
    Co-Authors: L. V. Danilov, G. G. Zegrya
    Abstract:

    The basic processes and mechanisms of Auger Recombination of nonequilibrium carriers in a semiconductor heterostructure with deep InAs0.84Sb0.16/AlSb quantum wells (QWs) are analyzed. It is shown that a zero-threshold Auger Recombination process involving two heavy holes predominates in sufficiently narrow QWs, and a resonant process involving two electrons is dominant in wide QWs. The range of QW widths at which the Auger Recombination is suppressed in a given structure to the greatest extent (suppression region) is determined. In this case, the threshold process involving two electrons remains the basic nonradiative Recombination process, with its probability being several orders of magnitude lower than those for the zero-threshold and resonant mechanisms. In turn, the zero-threshold mechanism involving two electrons is totally impossible in the heterostructure under study because of the large conduction-band offset (which markedly exceeds the energy gap). Also, the range of emission wavelengths that corresponds to the suppression region is estimated. It is shown that the interval calculated belongs to the mid-IR range.

  • Mechanisms of Auger Recombination in semiconducting quantum dots
    Journal of Experimental and Theoretical Physics, 2007
    Co-Authors: G. G. Zegrya, D. M. Samosvat
    Abstract:

    Microscopic calculation of the probability of Auger Recombination of charge carriers localized in a semiconducting quantum dot (QD) is carried out. It is shown that two mechanism of Auger Recombination (nonthreshold and quasi-threshold) operate in the QD. The nonthreshold Auger Recombination mechanism is associated with scattering of a quasimomentum from a heterobarrier, while the quasi-threshold mechanism is connected with spatial confinement of the wave functions of charge carriers to the QD region; scattering of carriers occurs at the short-range Coulomb potential. Both mechanisms lead to a substantial enhancement of Auger Recombination at the QD as compared to a homogeneous semiconductor. A detailed analysis of the dependence of Auger Recombination coefficient on the temperature and QD parameters is carried out. It is shown that the nonthreshold Auger Recombination process dominates at low temperatures, while the quasi-threshold mechanism prevails at high temperatures. The dependence of the Auger Recombination coefficient on the QD radius experiences noticeable changes as compared to quantum wells and quantum filaments.

  • Relationship between quasi-threshold and thresholdless Auger Recombination processes in InAs/GaAs quantum dots
    Technical Physics Letters, 2006
    Co-Authors: A. S. Shkolnik, Vadim P. Evtikhiev, G. G. Zegrya
    Abstract:

    The principal mechanisms of the nonradiative (Auger) Recombination of nonequilibrium charge carriers in semiconductor heterostructures with quantum dots (QDs) are considered. It is shown that the Auger Recombination process in QDs can proceed, in addition to a threshold mechanism, by means of two other substantially different mechanisms—thresholdless and quasi-threshold—and either of these can predominate, depending on the QD size. For a QD radius of ∼30 A, the probability of Auger Recombination is comparable with that of radiative Recombination.

  • A numerical calculation of Auger Recombination coefficients for InGaAsP/InP quantum well heterostructures
    Semiconductors, 2000
    Co-Authors: N. A. Il’in, A. S. Polkovnikov, G. G. Zegrya
    Abstract:

    Auger Recombination coefficients are calculated numerically for InGaAsP/InP quantum well heterostructures. In narrow quantum wells, the quasi-threshold and thresholdless mechanisms mainly contribute to the Auger Recombination coefficient. For the processes involving two electrons and a heavy hole (CHCC) or an electron and two heavy holes with a transition of one of the holes to the spin-orbit split-off band (CHHS), the Auger Recombination coefficients depend on temperature only slightly in a wide temperature range. The dependence of the Auger coefficient on the quantum well width is analyzed and found to be nonmonotonic.

  • Mechanisms of Auger Recombination in quantum wells
    Journal of Experimental and Theoretical Physics, 1998
    Co-Authors: G. G. Zegrya, A. S. Polkovnikov
    Abstract:

    The main mechanisms for the Auger Recombination of nonequilibrium carriers in semiconductor quantum-well heterostructures are investigated. It is shown for the first time that there are three fundamentally different Auger Recombination mechanisms in quantum wells: 1) a threshold-free mechanism, 2) a quasithreshold mechanism, and 3) a threshold mechanism. The rate of the threshold-free process has a weak temperature dependence. The rate of the quasithreshold Auger process exhibits an exponential temperature dependence. However, the threshold energy depends significantly on the quantum-well width and is close to zero for narrow quantum wells. It is shown that the threshold-free and quasithreshold processes are dominant in fairly narrow quantum wells, while the quasithreshold and threshold Auger processes are dominant in wide quantum wells. The limiting transition to a three-dimensional Auger process is accomplished for a quantum-well width tending to infinity. The value of the critical quantum-well width, at which the quasithreshold and threshold Auger processes combine to form a single three-dimensional Auger Recombination process, is found.

Tony F. Heinz - One of the best experts on this subject based on the ideXlab platform.

  • Auger Recombination of Excitons in Semiconducting Carbon Nanotubes
    Ultrafast Phenomena XV, 2007
    Co-Authors: Feng Wang, Mark S. Hybertsen, Gordana Dukovic, Louis E. Brus, Tony F. Heinz
    Abstract:

    The dynamics of the excitons in semiconducting single-walled carbon nanotubes are investigated by time-resolved fluorescence measurements. Auger Recombination of excitons on the picosecond timescale is observed and compared with theory.

  • Auger Recombination of excitons in one-dimensional systems
    Physical Review B, 2006
    Co-Authors: Feng Wang, Mark S. Hybertsen, Tony F. Heinz
    Abstract:

    In tightly confined one-dimensional (1D) systems, the effective Coulomb interaction is greatly enhanced and optical transitions generally lead to the formation of strongly bound excitons. When more than one exciton is present, the Coulomb interaction also leads to rapid exciton-exciton annihilation through an Auger Recombination process. This effect, which may be significant even at low exciton densities, can be described by a rate law governing two-body interactions. The Auger Recombination rate for excitons in a strongly confined 1D system is analyzed. The rate increases sharply with exciton binding energy, but varies only weakly with temperature. An explicit expression for the Auger Recombination rate in terms of the exciton binding energy, optical matrix element and reduced carrier mass is derived for a two-band model in which the Coulomb interaction is approximated by a point-contact potential. Results for the prototypical 1D system of single-walled carbon nanotubes are obtained and compared with experiment.

Todd D Krauss - One of the best experts on this subject based on the ideXlab platform.

  • quantized bimolecular Auger Recombination of excitons in single walled carbon nanotubes
    Physical Review Letters, 2006
    Co-Authors: Libai Huang, Todd D Krauss
    Abstract:

    Auger-like exciton-exciton annihilation in isolated single-walled carbon nanotubes (SWNTs) has been studied by femtosecond transient absorption spectroscopy. We observe a quantization of the Auger Recombination process and extract dynamics for 2 and 3 electron-hole pair excited states. We further demonstrate that Auger Recombination in SWNTs is a two-particle process involving strongly bound excitons and not a three-particle Auger process involving unbound electrons and holes. We thus provide explicit experimental evidence for one-dimensional discrete excitons in SWNTs.

Kazuyuki Watanabe - One of the best experts on this subject based on the ideXlab platform.

  • Auger-Recombination induced photocurrents in single-walled carbon nanotubes
    Applied Physics Express, 2009
    Co-Authors: Satoru Konabe, Takahiro Yamamoto, Kazuyuki Watanabe
    Abstract:

    Photocurrents in single-walled carbon nanotubes are theoretically investigated with focus on the excitonic effects and a new method to generate photocurrents due to E11-exciton dissociation through the Auger Recombination process is proposed. Those photocurrents whose carriers are dissociated E11-excitons abruptly increase at the threshold laser-intensity, due to the efficient Auger Recombination associated with exciton–exciton scattering. Our calculation predicts that by increasing the laser-intensity, the current originating from dissociated E11-excitons significantly increases compared with that from electron–hole pairs of band-to-band excitations.

Aleksey D. Andreev - One of the best experts on this subject based on the ideXlab platform.

  • Effect of strain on the Auger Recombination processes in type-II heterostructures with QWs
    Physics and Simulation of Optoelectronic Devices V, 1997
    Co-Authors: Aleksey D. Andreev, G. G. Zegrya
    Abstract:

    Auger Recombination processes in type II heterostructures with strained quantum wells (QW) have been studied theoretically. It is shown that in type II QW there are two channels of electron and hole Recombination. During the Auger Recombination processes these two channels interfere destructively, which results in decrease of the Auger matrix element and the AR rate. During radiative Recombination process one of these Recombination channels is the dominant. It is shown that the Auger Recombination rate essentially depends on strain. It is demonstrated that under certain conditions the Auger Recombination rate can be suppressed by choosing the optimal value of strain.

  • Mechanism of suppression of Auger Recombination processes in type-II heterostructures
    Applied Physics Letters, 1995
    Co-Authors: G. G. Zegrya, Aleksey D. Andreev
    Abstract:

    The mechanism of Auger Recombination in type‐II heterostructures is studied theoretically. It is shown that the Auger Recombination rate is a power function of temperature rather than an exponential function as in bulk materials. The feasibility of suppression of the Auger Recombination process in the type‐II heterostructures is demonstrated. The possibility of controlling the Auger Recombination rate is shown to be very important for development of optoelectronic devices with improved characteristics.