Annealing behaviour of electrically active point defects in gamma-irradiated n-GaN films

Formation processes and annealing of defects in gamma-irradiated n-GaN are investigated for the first time using electrical measurements and Raman spe ctroscopy. The production rate of defects turned out to be dependent on the dopant concentration. This suggests that at least one kind of native defec t is involved in impurity-defect interactions. Two prominent stages of defe ct annealing are revealed. The annealing processes at T greater than or equ al to 100 degrees C are associated with mobile native defects. A considerab le fraction of radiation defects is still present in the material after an annealing step at T greater than or equal to 750 degrees C. (C) 2000 Elsevi er Science B.V. All rights reserved.