Growth of epitaxial GaN films by pulsed laser deposition

High crystalline quality epitaxial GaN films with thicknesses 0.5-1.5 mu m have been successfully grown directly on Al2O3(0001) substrate by pulsed laser deposition (PLD). For films grown at 950 degrees C, we obtained an x-ray diffraction rocking curve linewidth of 7 are min. The ion channeling minimum yield in the near-surface region (similar to 2000 Angstrom) for a 0.5 mu m thick film was similar to 3%-4% indicating a high degree of crystallinity, The optical absorption edge measured by UV-visible spectroscopy Miss sharp. and tbe band gap was found to be 3.4 eV. The crystalline properties of these PLD GaN films are comparable to those grown by metalorganic chemical vapor deposition and molecular beam epitaxy. (C) 1997 American Institute of Physics.