Wang, S.-L.S.-L.WangYeh, B.-C.B.-C.YehWu, H.-M.H.-M.WuLUNG-HAN PENGLai, C.-M.C.-M.LaiKo, T.-S.T.-S.KoLu, T.-C.T.-C.LuWang, S.-C.S.-C.WangKung, A.-H.A.-H.Kung2018-09-102018-09-102008-0118626351http://scholars.lib.ntu.edu.tw/handle/123456789/342867https://www.scopus.com/inward/record.uri?eid=2-s2.0-77951230283&doi=10.1002%2fpssc.200778636&partnerID=40&md5=d5652b4fdc565528a87f9825bd266416We report the observation of green emission centered at 500nm, accompanied with luminescence enhancement and spectral blue shift (∼31meV) in the bandedge emission from a-plane grown gallium nitride (GaN) passivated with gallium hydroxide (GaOOH). From study of the photo-current response and polarization-resolved low-temperature microphotoluminescence (μ-PL) we resolved an evolution of gain competition process between the green and the UV emission bands. By dissolving the oxide we recover the emission characteristics of the as-grown a-GaN. These observations can be ascribed to a formation of compressively-strained a-GaN due to a coherently grown GaOOH atop layer. The latter is responsible for the spectral blue shift and the generation of acceptor like deep-levels causing the green-band transition in the emission and photo-current response. Enhancement of bandedge emission from the oxide covered a-GaN is due to the GaOOH surface passivation effect which was prepared by the photo-enhance wet oxidation method. © 2008 Wiley-VCH Verlag GmbH & Co. KGaA.A-plane; A-plane GaN; As-grown; Band transitions; Band-edge emissions; Blue shift; Current response; Deep-levels; Emission characteristics; Gain competition; Green emissions; Low temperatures; Luminescence enhancements; Microphotoluminescence; Surface passivation; UV emissions; Wet oxidation; Dissolution; Gallium alloys; Optical properties; Passivation; Gallium nitrideconference paper10.1002/pssc.2007786362-s2.0-77951230283