A point defect complex related to the yellow luminescence in electron irradiated GaN

Point defect complexes related to the yellow luminescence (YL; ∼2.2 eV) produced in un-doped GaN by 30 MeV electron irradiation are studied using a photoluminescence method. The YL intensity in 700°C annealed samples is about five times larger than that in un-irradiated materials, indicating that deep level defects are created by electron irradiation and subsequent annealing. The YL is associated with point defect complexes arising from the combination of the irradiation introduced Ga vacancies and the residual donor impurities driven by high temperature annealing. The YL is not annealed out by annealing at 1000°C, showing the thermal stability of artificially introduced defects.