Photoluminescence and X-ray absorption spectroscopy measurement were used to characterize the near-band edge emission intensity and electronic structure of as-implanted GaN nanowires that had been implanted with Eu ions to different fluences. The N K- and Ga L3-edge of total electron yield X-ray absorption spectra showed the formation of N interstitials (Ni) and dangling bond (Ndb) point defects and the formation of metallic Ga layers on the surface of nanowires. X-ray diffraction, Ga K- and L3-edge of total fluorescence yield X-ray absorption spectra consistently revealed the wurtzite structure of the as-implanted nanowires up to the highest fluence. The ratio of absorption intensity found in sp3 and sp2 environment and the near-band edge intensity were strongly affected by the implantation. It was suggested that the decrease of near-band edge intensity was closely related to the change from sp3 to sp2 environment. The absorption intensity ratio between the as-grown and as-implanted samples of Ndb and Ni was directly proportional to the fluences indicating that these defects were preferentially formed during implantation.

The Characterization of N Interstitials and Dangling Bond Point Defects on Ion-Implanted GaN Nanowires Studied by Photoluminescence and X-Ray Absorption Spectroscopy. K.H.Lee, J.W.Chiou, J.M.Chen, J.F.Lee, A.Braud, K.Lorenz, E.Alves, I.G.Chen: Journal of the American Ceramic Society, 2010, 93[11], 3531-4