Growth of epitaxial GaN films by pulsed laser deposition

Abstract

High crystalline quality epitaxial GaN films with thicknesses 0.5–1.5 μm have been successfully grown directly on Al2O3(0001) substrate by pulsed laser deposition (PLD). For films grown at 950 °C, we obtained an x-ray diffraction rocking curve linewidth of 7 arc min. The ion channeling minimum yield in the near-surface region (∼2000 Å) for a 0.5 μm thick film was ∼3%–4% indicating a high degree of crystallinity. The optical absorption edge measured by UV-visible spectroscopy was sharp, and the 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.