Photoluminescence and photoluminescence excitation spectroscopic studies were performed, at 6K, on the 1540nm 4I13/2-4I15/2 emissions of Er3+ in Er-implanted and annealed material. The studies revealed the existence of multiple Er3+ centres and associated photoluminescence spectra in Er-implanted films which were grown by means of metalorganic chemical vapour deposition, hydride vapour-phase epitaxy or molecular beam epitaxy. The results demonstrated that the multiple Er3+ photoluminescence centres, and below-gap defect-related absorption bands by which they were selectively excited, were universal features of Er-implanted GaN which was grown using differing techniques. It was suggested that implantation-induced defects which were common to all GaN samples were responsible for the Er-site distortions that gave rise to the distinctive selectively-excited Er3+ photoluminescence spectra. Investigations were also made of selectively excited Er3+ photoluminescence and photoluminescence excitation spectra from Er-implanted samples of Mg-doped GaN which were grown using various techniques. In each of these samples, the so-called violet-pumped Er3+ photoluminescence band and its associated broad violet photoluminescence excitation band were significantly enhanced; relative to the photoluminescence and photoluminescence excitation data for other selectively excited Er3+ photoluminescence centres. The violet-pumped Er3+ photoluminescence spectra dominated the above-gap excited Er3+ photoluminescence spectrum of Er-implanted Mg-doped GaN. It was unobservable under above-gap excitation in Er-implanted undoped GaN. The results were suggested to confirm that suitable co-dopants could increase the efficiency of trap-mediated above-gap excitation of Er3+ emissions from Er-implanted GaN.

Effects of Material Growth Technique and Mg Doping on Er Photoluminescence in Er3+-Implanted GaN. S.Kim, R.L.Henry, A.E.Wickenden, D.D.Koleske, S.J.Rhee, J.O.White, J.M.Myoung, K.Kim, X.Li, J.J.Coleman, S.G.Bishop: Journal of Applied Physics, 2001, 90[1], 252-9