High-quality m-plane GaN thin films deposited on γ-LiAlO2 by ion-beam-assisted molecular-beam epitaxy -: art. no. 011902

GaN(1 (1) over bar 00) thin films are deposited on gamma-LiAlO2(100) by low-energy-ion-beam-assisted molecular-beam epitaxy. Structural properties of the epitaxial GaN films are investigated by x-ray diffraction, transmission electron microscopy, and atomic force microscopy. X-ray diffraction measurements give evidence for a high crystalline quality far better than previously reported in literature. Cross-section transmission electron microscopy and atomic force microscopy show an anisotropy in defect structure and surface topography parallel and perpendicular to the GaN c axis. Optical properties are examined by photoluminescence spectroscopy at various temperatures. The spectra exhibit a strong and sharp near-band-gap transition, as well as a donor-acceptor pair transition. (c) 2006 American Institute of Physics.