THE EFFECT OF ACOUSTIC-PHONON CONFINEMENT ON THE MOMENTUM AND ENERGY RELAXATION OF HOT CARRIERS IN QUANTUM WIRES

The momentum and energy relaxation rates associated with electron-acou stic phonon interaction in a free-standing rectangular GaAs quantum wi re have been calculated taking into account confined and interface pho non modes. Phonon confinement has two major consequences: (i) it incre ases relaxation rates by several orders of magnitude, and (ii) it incr eases the ratio of absorption to emission processes in narrow interval s of energy thereby making the energy relaxation rate in these interva ls negative. An external magnetic field always decreases the momentum relaxation rate (thus increasing the carrier mobility) even though the scattering rate (the inverse of the quasi-particle lifetime) may incr ease or decrease depending on whether the interaction is polar (piezoe lectric) or non-polar (deformation potential).