Photoluminescence of dislocations in plastically deformed GaN

Abstract

Fresh (a/3) [ 1 1 2 ¯ 0 ] dislocations on the ( 1 1 ¯ 0 0 ) prismatic plane were introduced into GaN bulk crystals by plastic deformation at 950 °C. Photoluminescence (PL) studies at 11 K showed that the near band edge (3.48 eV) luminescence intensity decreased drastically in the deformed GaN, attributed to the introduction of a high-density of non-radiative recombination centers during plastic deformation. The yellow band (2.22 eV) luminescence decreased by plastic deformation, while several luminescence bands centered at 1.79, 1.92, 2.4 and 2.8 eV developed. The dependence of PL features on deformation and annealing indicates that yellow luminescence is not related to the native structure of dislocations in GaN.