Cathodoluminescence depth profiling of ion-implanted GaN

Cathodoluminescence (CL) spectroscopy shows that even relatively low-dose k eV light-ion bombardment (corresponding to the generation of similar to 5x1 0(19) vacancies/cm(3)) of wurtzite GaN results in a dramatic quenching of v isible CL emission. Postimplantation annealing at temperatures up to 1050 d egreesC generally causes a partial recovery of measured CL intensities. How ever, CL depth profiles indicate that, in most cases, such a recovery resul ts from CL emission from virgin GaN, beyond the implanted layer due to a re duction in the extent of light absorption within the implanted layer. In th is case, CL emission from the implanted layer remains completely quenched e ven after such an annealing. These results show that an understanding of th e effects of ion bombardment and postimplantation annealing on luminescence generation and light absorption is required for a correct interpretation o f luminescence spectra of GaN optically doped by keV ion implantation. (C) 2001 American Institute of Physics.