The density of the vacancy-type defect in Er-doped GaN was measured by positron annihilation spectrometry and the correlation between the intensity of the Er-related luminescence was studied. A luminescence peak at 558nm originating from 4S3/2 to 4I15/2 transition of Er3+ was observed in Er-doped GaN. The intensity of the luminescence increased with increasing Er concentration and showed the maximum with the Er concentration of around 4.0at%. The positron annihilation spectrometry measurements showed that the vacancy-type defect density increased with increasing Er concentration up to 4at%, and around 4at% of Er, the formation of defect complex such as VGa–VN was suggested. The contribution of the defect to the radiative recombination of intra-4f transition of Er was considered.

Relationship between Defects and Optical Properties in Er-Doped GaN. S.Chen, A.Uedono, J.Seo, J.Sawahata, K.Akimoto: Journal of Crystal Growth, 2009, 311[10], 3097-9