Theoretical modeling of nonequilibrium optical phonons and electron energy relaxation in GaN

Abstract

The decay of the zone-center longitudinal optical (LO) phonon in GaN into a transverse optical (TO) phonon and a longitudinal acoustic (LA) phonon is theoretically investigated. Its decay into two LA phonons is forbidden. A theoretical model is presented to study the effect of nonequilibrium LO and TO phonons on the electron energy relaxation rate. The electron energy relaxation time is calculated, and its value is shown to strongly depend on the finite lifetimes of both LO and TO phonons. The individual contributions of A1 mode and E1 mode optical phonons in the overall electron energy relaxation processes are also discussed.