58 research outputs found
Electron-Electron Relaxation Effect on Auger Recombination in Direct Band Semiconductors
Influence of electron-electron relaxation processes on Auger recombination
rate in direct band semiconductors is investigated. Comparison between
carrier-carrier and carrier-phonon relaxation processes is provided. It is
shown that relaxation processes are essential if the free path length of
carriers doesn't exceed a certain critical value, which exponentially increases
with temperature. For illustration of obtained results a typical InGaAsP
compound is used
Scattering states of coupled valence-band holes in point defect potential derived from variable phase theory
In this article we present a method to compute the scattering states of holes
in spherical bands in the strong spin-orbit coupling regime. More precisely, we
calculate scattering phase shifts and amplitudes of holes induced by defects in
a semiconductor crystal. We follow a previous work done on this topic by Ralph
[H. I. Ralph, Philips Res. Rept. 32 160 (1977)] to account for the p-wave
nature and the coupling of valence band states. We extend Ralph's analysis to
incorporate finite-range potentials in the scattering problem. We find that the
variable phase method provides a very convenient framework for our purposes and
show in detail how scattering amplitudes and phase shifts are obtained. The
Green's matrix of the Schroedinger equation, the Lippmann-Schwinger equation
and the Born approximation are also discussed. Examples are provided to
illustrate our calculations with Yukawa type potentials.Comment: 16 pages and 9 figure
Auger Recombination in Semiconductor Quantum Wells
The principal mechanisms of Auger recombination of nonequilibrium carriers in
semiconductor heterostructures with quantum wells are investigated. It is shown
for the first time that there exist three fundamentally different Auger
recombination mechanisms of (i) thresholdless, (ii) quasi-threshold, and (iii)
threshold types. The rate of the thresholdless Auger process depends on
temperature only slightly. The rate of the quasi-threshold Auger process
depends on temperature exponentially. However, its threshold energy essentially
varies with quantum well width and is close to zero for narrow quantum wells.
It is shown that the thresholdless and the quasi-threshold Auger processes
dominate in narrow quantum wells, while the threshold and the quasi-threshold
processes prevail in wide quantum wells. The limiting case of a
three-dimensional (3D)Auger process is reached for infinitely wide quantum
wells. The critical quantum well width is found at which the quasi-threshold
and threshold Auger processes merge into a single 3D Auger process. Also
studied is phonon-assisted Auger recombination in quantum wells. It is shown
that for narrow quantum wells the act of phonon emission becomes resonant,
which in turn increases substantially the coefficient of phonon-assisted Auger
recombination. Conditions are found under which the direct Auger process
dominates over the phonon-assisted Auger recombination at various temperatures
and quantum well widths.Comment: 38 pages, 7 figure
The effect of current crowding on the internal quantum efficiency of InAsSb/InAs light-emitting diodes
Exact asymptotic form of the exchange interactions between shallow centers in doped semiconductors
The method developed in [L. P. Gor'kov and L. P. Pitaevskii, Sov. Phys. Dokl.
8, 788 (1964); C. Herring and M. Flicker, Phys. Rev. 134, A362 (1964)] to
calculate the asymptotic form of exchange interactions between hydrogen atoms
in the ground state is extended to excited states. The approach is then applied
to shallow centers in semiconductors. The problem of the asymptotic dependence
of the exchange interactions in semiconductors is complicated by the multiple
degeneracy of the ground state of an impurity (donor or acceptor) center in
valley or band indices, crystalline anisotropy and strong spin-orbital
interactions, especially for acceptor centers in III-V and II-VI groups
semiconductors. Properties of two coupled centers in the dilute limit can be
accessed experimentally, and the knowledge of the exact asymptotic expressions,
in addition to being of fundamental interest, must be very helpful for
numerical calculations and for interpolation of exchange forces in the case of
intermediate concentrations. Our main conclusion concerns the sign of the
magnetic interaction -- the ground state of a pair is always non-magnetic.
Behavior of the exchange interactions in applied magnetic fields is also
discussed
Regenerative pulsations in semiconductor etalon due to competition between carrier generation and heating effects on band filling
Threshold and probability of impact ionization by electrons in narrow-gap p-type semiconductors with highly degenerate holes
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