Raman and photoluminescence spectroscopy from N-2(+)-ion implanted and alpha-irradiated and annealed GaN/sapphire

GaN on sapphire (SA) was both implanted by N-2(+) ions and alpha -particle irradiated from the GaN and substrate sides. Irradiation-induced vibration modes were observed in GaN. Raman spectra from the substrate reveal more dr astic changes. Photoluminescence spectroscopy shows a significant shift of the yellow band toward the higher energy. Annealing results in a good recov ery of GaN, while the substrate retains substantial structural damage. (C) 2001 Elsevier Science B.V. All rights reserved.