On the incoherence
of quantum transport in semiconductor
heterostructure optoelectronic devices
P. Harrison, Z. Ikoniã, N.
Vukmiroviã, D. Indjin, R.W. Kelsall and
V.D. Jovanoviã, University of Leeds,
U.K.ABSTRACT: This paper
compares and contrasts different
theoretical approaches with experimental
measurements of transport in
optoelectronic devices based on
semiconductor heterostructures. The Monte
Carlo method which makes no a priori assumptions
about the carrier distribution in
momentum or phase space is compared with
less computationally demanding
energy-balance rate equation models which
assume thermalised carrier distributions.
It is shown that the two approaches
produce qualitatively similar results for
the specific case of hole transport in p-type
Si1-xGex/Si
superlattices designed for terahertz
emission though there are signifi- cant
differences which originate in the
absolute values of the carrier kinetic
energy in the plane of the quantum wells.
In contrast to this, simulations of
electron transport in n-type
GaAs/Ga1-xAlxAs
terahertz quantum cascade lasers show a
more similar behaviour between both
theoretical approaches. In addition, the
very good comparison with experiment
substantiates the incoherent scattering
approach which underpins both methods.
Further evidence to support the
applicability of carrier transport in
semiconductor heterostructures at finite
temperature being dominated by incoherent
scattering, which can be modelled by
self-consistent energybalance rate
equations, is given by further
comparisons with experimental
measurements of two other categories of
devices namely quantum well infrared
photodetectors and quantum dot infrared
photodetectors.
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