LUMINESCENCE DYNAMICS OF EXCITON REPLICAS IN HOMOEPITAXIAL GAN LAYERS

Photoluminescence of excitons and their phonon replicas in homoepitaxi al MOCVD-grown gallium nitride (GaN) layers have been studied by picos econd tps) time-resolved photoluminescence spectroscopy. The time-reso lved photoluminescence spectroscopy has shown that the free excitons a nd their replicas have the fastest dynamics (decay time of about 100 p s). Then, the excitons-bound-to-donors emission rises (with the rise t ime similar to the free excitons decay time) and decays with t = 300 p s. The excitons-bound-to-acceptors has the slowest decay (about 500 ps ). It has been found that the ratio of excitons-bound-to-acceptors and excitons-bound-to-donors amplitudes and their decay times are differe nt for 1-LO replicas and then for zero-phonon lines, whereas the ratio of amplitudes and the decay time of the 2-LO replicas are similar to the ones of the zero-phonon lines.