Tipărire

C. E. A. Grigorescu, L. Torte, O. Monnereau, L. Argeme, H. J. Trodahl, S. Granville, A. Bittar, F. Budde, B. J. Ruck, G. V. M. Williams, G. Pavelescu, A. Tonetto, R. Notonier, C. Logofatu, Structural and optical properties of GaN-based nanocrystalline thin films, Thin Solid Films, 516/ 7 (2008) 1617 - 1621

 

Title: Structural and optical properties of GaN-based nanocrystalline thin films

Abstract: We study the effect of annealing on structure, morphology and optical properties of nanocrystalline films of GaN, GaN:O and GaN:Mn prepared by ion assisted deposition on silicon, quartz and glassy carbon substrates. Blisters and holes having diameters proportional with the thickness of the film were observed in GaN:O deposited on silicon and glassy carbon. The Mn excess in GaN:Mn turns through annealing into MnxNy islands. The degree of short- and intermediate-range order in the films was investigated by micro-Raman spectroscopy, extending to about 3 nm for gallium oxynitride films annealed to 973 K and to more than 10 nm in GaN samples. A diminished oxygen content following the annealing procedures on GaN:O samples is noticed from the reduced intensity of the oxygen mode at 1000 cm(-1) in the Raman spectra. This observation is supported with X-ray photoemission spectroscopy measurements. The presence of oxygen at concentrations above 15at.% in the films leads to an abrupt nanocrystalline-amorphous transition

Key words: ion assisted deposition; gallium nitride; annealing; scanning electron microscopy; X-ray diffraction; X-ray photoemission spectroscopy; Raman spectroscopy; short range order