Optical study of hot electron transport in GaN: Signatures of the hot-phonon effect

The hot-phonon lifetime in GaN is measured by temperature- and electric field-dependent photoluminescence studies of a $n$-type channel. The rate of increase of electron temperature with the external electric field provides a signature of nonquilibrium hot-phonon accumulation. Hot-electron temperatures are measured directly as a function of applied electric fields, and by comparing theoretical models for electron energy-loss into acoustic and optical phonons, a hot-phonon lifetime of $τph=3$ to 4 ps is extracted.