Characterization of GaN films grown on silicon (1 1 1) substrates

High-quality gallium Nitride (GaN) films were prepared by reactive annealing sputtered gallium oxide (Ga2O3) films on Si (1 1 1) substrates in flowing ammonia. X-ray diffraction, X-ray photoelectron spectroscopy, and the selected area electron diffraction patterns reveal that the films consist of hexagonal wurtzite GaN with c-axis orientated polycrystalline grains. Intense room-temperature photoluminescence peaked at 354 nm of the films is observed. The band gap of these films has a blueshift with respect to bulk GaN