Photoluminescence properties of GaN with dislocations induced by plastic deformation

Fresh (a/3)[1120] dislocations on the (1100) prismatic plane were introduced into GaN bulk crystals by plastic deformation at 950-1000°C. In photoluminescence studies at 11 K, the near-band-edge (3.48 eV) luminescence intensity decreased remarkably in the deformed GaN, which was attributed to the introduction of high-density nonradiative recombination centers during plastic deformation. The yellow-band luminescence (2.22 eV) decreased due to plastic deformation, while several luminescence bands centered at 1.79, 1.92, and 2.4 eV developed. The dependence of PL features on deformation and annealing suggests that yellow luminescence is not related to the native structure of edge dislocations in GaN.