Study of photoluminescence from self-formed GaAs nanocrystallites in As-doped GaN grown by molecular beam epitaxy

We report on the results of the investigation of the photoluminescence (PL) from GaAs nanocrystallites embedded in a GaN host crystal and formed during the growth of GaN(As) by molecular beam epitaxy. The low-temperature PL spectra reveal two emission bands with maxima at 1.20 and 1.43 eV. The en-fission intensities of both PL bands show a characteristic 2/3 power-law dependence upon the optical excitation intensity, suggesting a strong contribution of Auger recombination in the total recombination rate of non-equilibrium carriers inside the GaAs nanocrystallites. The integral PL intensity demonstrates a sharp maximum in the growth temperature dependence at similar to780 degreesC. This can be explained by the competition of several temperature-dependent processes, which influence the formation of the GaAs nanocrystallites.