G. Paulavicius et al., COUPLED ELECTRON AND NONEQUILIBRIUM OPTICAL PHONON TRANSPORT IN A GAAS QUANTUM-WELL, Journal of applied physics, 82(11), 1997, pp. 5580-5588
The self-consistent Monte Carlo technique has been used to solve coupl
ed nonlinear kinetic equations for electrons and optical phonons confi
ned in a GaAs quantum well. We have studied the influence of nonequili
brium phonons on quasi-two-dimensional electron transport for a lattic
e temperature of 30 K and for a wide range of applied electric fields.
A substantial difference in generation and decay times as well as the
confinement inside the GaAs/AlAs heterostructure-bounded active regio
n lead to a significant growth of nonequilibrium optical-phonon popula
tion generated by a heated electron gas. We have found that when the p
honon generation (as well as phonon reabsorption by the quasi-two-dime
nsional carriers) becomes significant, there are substantial effects-o
n transport in the quantum well. We show that for low electron concent
rations, the hot optical-phonon distribution reflects the main feature
s of the carrier distribution; indeed, it preserves an average quasi-m
omentum in the forward (opposite to electric field) direction. However
, hot-phonon feedback to the electron system is found to be not essent
ial in this case. For high electron concentrations, enhanced nonequili
brium optical-phonon reabsorption results in phonon distribution which
spreads significantly in the quasi-momentum space and essentially los
es the characteristic of the forward-peaked anisotropy. The interactio
ns with the confined electron subsystem typically result in an isotrop
ic phonon distribution. In this case, nonequilibrium optical phonons l
ead to an increase in the mean electron energy and a reduction in the
carrier drift velocity. (C) 1997 American Institute of Physics.