A striking similarity was noted between the 0.88eV photoluminescence in GaN and the 0.841eV photoluminescence from the substitutional OP donor in GaP. The main localized phonons, which were regarded as being characteristic of local vibrations which involved OP in GaP, were replicated by the 0.88eV photoluminescence in GaN. It was suggested that the 0.88eV photoluminescence might originate from an electronic transition which was related to the substitutional ON donor in GaN. This was either isolated ON, or a complex which involved ON. In such a model, the isolated ON in GaN could be a deep donor and could therefore not be responsible for a residual n-type conductivity.

Similarity between the 0.88eV Photoluminescence in GaN and the Electron-Capture Emission of the OP Donor in GaP. W.M.Chen, I.A.Buyanova, M.Wagner, B.Monemar, J.L.Lindström, H.Amano, I.Akasaki: Physical Review B, 1998, 58[20], R13351-4