Two Mg-doped GaN films with different doping concentrations were grown by a metalorganic chemical vapor deposition technique. Photoluminescence experiments were carried out to investigate the optical properties of these films. For highly Mg-doped GaN, the photoluminescence spectra at 10K were composed of a blue luminescence band at 2.857eV and 2 excitonic luminescence lines at 3.342eV and 3.282eV, in addition to a L2 phonon replica at 3.212eV. The intensity of the L1 line decreases monotonously with an increase in temperature. However, the intensity of the L2 line first slowly increased, and then decreases quickly with an increase in temperature. The two lines were attributed to bound excitonic emissions at extended defects. The blue luminescence band was most likely due to the transition from deep donor Mg–VN complex to Mg shallow acceptor. From the temperature dependence of the luminescence peak intensity of the blue luminescence band, the activation energy of acceptor Mg was found to be 0.29eV.

Photoluminescence of Mg-Doped GaN Grown by Metalorganic Chemical Vapor Deposition. B.Z.Qu, Q.S.Zhu, X.H.Sun, S.K.Wan, Z.G.Wang, H.Nagai, Y.Kawaguchi, K.Hiramatsu, N.Sawaki: Journal of Vacuum Science & Technology A, 2003, 21[4], 838-41