Annealing behavior of luminescence from erbium-implanted GaN films

We have conducted a systematic study of the bandedge and infrared luminesce nce properties of Er-implanted GaN thin films. The GaN films, grown by meta lorganic chemical vapor deposition, were co-implanted with Er and O ions. A fter implantation, the implanted samples were furnace annealed at temperatu res up to 1100 degreesC. Following annealing, the samples were examined for both bandedge luminescence and for infrared luminescence near 1540 nm. It was observed that the bandedge photoluminescence (PL) was significantly red uced in the as-implanted samples. In addition, there was no detectable PL s ignal near 1540 nm, with either above-bandgap or below-bandgap excitation. Only after annealing at temperatures above 900 degreesC did both the banded ge luminescence and the 1540 nm luminescence become well defined. An optica l transition at 3.28 eV was also observed, apparently induced through Er O implantation. While annealing at higher temperatures resulted in a decrea se in the 1540 nm luminescence, emission intensities from the bandedge and the defect level both increased. (C) 2001 Elsevier Science B.V. All rights reserved.