HOT-PHONON EFFECTS ON ELECTRON-TRANSPORT IN QUANTUM WIRES

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.