ELECTRON-PHONON SCATTERING IN GA1-XALXAS QUANTUM-WELL STRUCTURES IN AN ELECTRIC-FIELD

Effects of the well width and an electric field on electron-phonon sca ttering are studied for two kinds of quantum-well structures. One is a symmetrical single quantum well (SSQW) Ga0.6Al0.4As/GaAs/Ga0.6Al0.4As , and the other is an asymmetrical single quantum well (ASQW) Ga0.6Al0 .4As/GaAs-Ga0.8Al0.2As/Ga0.6Al0.4As. Calculated results reveal that fo r both structures without an electric field, the intrasubband and inte rsubband scattering rates due to interface phonons, respectively, decr ease and increase with increasing well width while those due to confin ed phonons increase with increasing well width. It is found that the d ifference between SSQW and ASQW structures results in a significant ch ange of phonon modes and electronic structure and consequently the dep endence of scattering rates on an applied electric field is quite diff erent for the two structures, and that the intersubband scattering rat es can be considerably changed by applied electric field as the well w idth is large. The result would be useful for analyzing experimental r esults and designing some devices in the future.