Numerical analysis of the relaxation of photoexcited carriers and the hot-phonon effect in GaN

The ultrafast relaxation kinetics of the photo-injected plasma in polar semiconductors has been analyzed with certain details resorting to a first-principles quantum theory based on a nonequilibrium ensemble formalism (the non-equilibrium statistical operator method). Particular attention was given to the so-called hot-phonon effect that accompanies the rapid relaxation processes in the photo-injected plasma. This is done by studying the process of generation and decay of the nonequilibrium longitudinal optical (LO) phonon population per mode. Numerical calculations are presented for the GaN, particular attention being paid to the influence of the carriers effective mass and the time relaxation of the LO-phonons population in the process.