Hot (nonequilibrium) phonon effects on electron transport in rectangul
ar GaAs/AlAs quantum wires have been investigated by a self-consistent
Monte Carlo simulation. Confinement and localization of optical phono
ns have been taken into account. We have demonstrated that at room tem
perature hot optical phonons lead to a significant increase in electro
n drift velocity. This hot-phonon drag effect is due to the strongly a
symmetric nonequilibrium phonon distribution. As a result, phonon abso
rption for forward transitions (electron gains momentum along electric
field) is enhanced, whereas absorption for backward transitions (elec
tron gains momentum against electric field) is suppressed. At low temp
eratures diffusive heating of electrons by hot phonons dominates over
hot-phonon drag and the electron drift velocity decreases. (C) 1996 Am
erican Institute of Physics.