ABSTRACT
Mg-doped cubic GaN was grown on a GaAs (100) substrate by metalorganic vapor-phase epitaxy. Two free-electron-to-Mg-acceptor-transition peaks were observed from photoluminescence of an as-grown sample at 32 K. Two donor-acceptor-pair emission peaks related to Mg levels were observed in photoluminescence measurements at 32 K after thermal annealing treatment, which decreased the free carrier concentration of the films. The two twin peaks were interpreted as emissions related to Mg levels in the cubic and hexagonal-like phase, which was inserted as a stacking fault.
