Mechanisms of band-edge emission in Mg-doped p-type GaN

Time-resolved photoluminescence has been employed to study the mechanisms of band-edge emissions in Mg-doped p-type GaN. Two emission lines at about 290 and 550 meV below the band gap (Eg) have been observed. Their recombination lifetimes, dependencies on excitation intensity, and decay kinetics have demonstrated that the line at 290 meV below Eg is due to the conduction band-to-impurity transition involving shallow Mg impurities, while the line at 550 meV below Eg is due to the conduction band-to-impurity transition involving doping related deep-level centers (or complexes).