Thermally assisted recovery of low energy electron beam irradiation induced optical degradation of GaN

In this paper, we present our studies on thermally assisted recovery of low energy electron beam induced optical degradation of gallium nitride. A clear reduction in MOVPE grown GaN band-to-band photoluminescence intensity induced by low energy electron beam irradiation has been found before. Partial recovery of the band-toband emission was observed after annealing in both H2 and N2 ambient, at 500 °C for 35 sec-52 h. The photoluminescence intensity was reduced to approximately 15 % by the low energy electron beam irradiation and recovered to maximum of 40% of the non-irradiated level. The recovery saturated after approximately 1 minute of annealing. Since hydrogen passivated Ga-vacancies have been shown to be activated by the electron beam treatment, a plausible recovery mechanism is suggested to involve re-passivation of these vacancies due to internal hydrogen diffusion in the sample.