Good evidence for amphoteric native defect reactions was obtained via the photoluminescence analysis of Si-doped (1.5 x 1018/cm3) samples which had been annealed under various conditions. Thus, annealing in an excess of As4 vapor created a large concentration of Ga vacancies, and made possible the transformation of this defect into an As vacancy plus an As antisite defect. In the same way, As vacancies which were generated at high concentration during annealing under Ga-rich conditions were transformed into Ga vacancies and Ga antisite defects. A shift of the Fermi level towards the valence band during annealing in the As4 over-pressure resulted in the transformation of VGa into VAs and AsGa. A Fermi-level position close to the conduction band, under Ga-rich conditions, favoured the transformation of VAs into VGa and GaAs. Photoluminescence intensities which were associated with the corresponding defects were in qualitative agreement with the predictions of the mass action law, as applied to amphoteric native defect reactions.

N.H.Ky, F.K.Reinhart: Journal of Applied Physics, 1998, 83[2], 718-24