Nanocrystalline gallium nitride thin films

Nanocrystalline gallium nitride (GaN) thin films were deposited on quartz substrates by reactive rf sputtering of GaAs target with nitrogen as the reactive cum sputtering gas. X-ray diffraction and transmission electron microscopy confirmed the presence of GaN crystallites with particle size increasing from 3 to 16 nm, as the substrate temperature was increased from 400 to 550 °C. The particle size in films grown at temperatures below 550 °C were less than the exciton Bohr radius of GaN. The band gap of these films obtained from absorption and photoluminescence measurements showed a blueshift with respect to bulk GaN.