The stability of the defects in Mg-doped material was investigated by using photoluminescence spectroscopy. The 2 predominant defect-related photoluminescence emission bands in p-type material, the blue band at 2.8eV and the ultra-violet emission band at 3.27eV, were investigated. The intensity of the 3.27eV photoluminescence band increased with increasing resistivity, whereas the 2.8eV photoluminescence band intensity increased with a decrease in resistivity. The luminescence data were explained in terms of a model in which the concentration of luminescent centers depended upon the Fermi level position. The shallow donor which was responsible for the ultra-violet band was attributed to H, whereas the deep donor defect which was responsible for the 2.8eV band was attributed to a N vacancy complex.

Investigation of the Formation of the 2.8eV Luminescence Band in p-Type GaN:Mg F.Shahedipour, B.W.Wessels: Applied Physics Letters, 2000, 76[21], 3011-3