Structural and optical properties of GaN-based nanocrystalline thin films

• Published in: Thin solid films Vol. 516; no. 7; pp. 1617 - 1621
• Main Authors: Grigorescu, C.E.A., Tortet, L., Monnereau, O., Argeme, L., Trodahl, H.J., Granville, S., Bittar, A., Budde, F., Ruck, B.J., Williams, G.V.M., Pavelescu, G., Tonetto, A., Notonier, R., Logofatu, C.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Lausanne Elsevier B.V 15.02.2008; Elsevier Science
• Subjects: Annealing; Cold working, work hardening; annealing, quenching, tempering, recovery, and recrystallization; textures; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Gallium nitride; Iii-v semiconductors; Ion and electron beam-assisted deposition; ion plating; Ion assisted deposition; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of specific thin films; Physics; Raman spectroscopy; Scanning electron microscopy; Short range order; Treatment of materials and its effects on microstructure and properties; X-ray diffraction; X-ray photoemission spectroscopy; Scanning electron microscopy; Annealing; X-ray photoemission spectroscopy; Ion assisted deposition; X-ray diffraction; Short range order; Raman spectroscopy; Gallium nitride; XRD; Ion beam assisted deposition method; Nanostructures; Property processing relationship; Thin films; Oxygen additions; Optical properties; Manganese nitrides; Thermal annealing; Manganese additions; Quartz; Silicon oxides; Morphology; Short-range order; Vitreous state; Gallium Oxynitrides; III-V semiconductors; X-ray photoelectron spectra
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2007.07.201

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.