Hot-electron energy dissipation and inter-electron collisions in GaN-WZ

We use the Monte Carlo technique to treat hot-electron energy dissipation on equilibrium phonons at a lattice temperature of 300 K in donor-doped wurtzite GaN subjected to an electric field. Two concur-rent energy relaxation processes (fast and ultrafast) are resolved. The energy relaxation time of the ultrafast process is similar to25 fs; its dependence on the field and the doping is very weak (if any). In contrast, pair electron-electron collisions are found to enhance the fast energy dissipation considerably. In particular, at a field of 0.2 W cm(-1), the relaxation time of the fast process decreases from 2.8 ps to 0.3 ps as the electron density increases from 4 x 10(15) cm(-3) to 3 x 10(17) cm(-3). The time decreases as the electric field increases; values below 0.1 ps are reached at 10(16) cm(-3) at fields exceeding 8 kV cm(-1).