Films of Mg-doped material were prepared by using metalorganic chemical vapor deposition and post-growth annealing (750C). A predominant photoluminescence line around 2.9eV was observed at room temperature. By studying the dependence of the photoluminescence upon excitation density at 20K, the emission line around 2.95eV could be attributed to a donor-to-acceptor pair transition rather than to a conduction band-to-impurity transition which involved a Mg-related deep level. It was suggested that the donor-to-acceptor transition line was caused by a Mg-related deep level at about 0.51eV above the valence band. It was much deeper than the acceptor level at 0.25eV which was commonly produced by Mg dopants.

Photoluminescence Spectroscopy of Mg-Doped GaN. J.K.Sheu, Y.K.Su, G.C.Chi, B.J.Pong, C.Y.Chen, C.N.Huang, W.C.Chen: Journal of Applied Physics, 1998, 84[8], 4590-4