Fabrication and characterization of GaN/amorphous Ga2O3 nanocables through thermal oxidation

In an effort to obtain one-dimensional core/shell nanostructures, thermal oxidation behavior of GaN nanowires in O2 with N2 ambients was investigated by x-ray diffraction, transmission electron microscopy, and x-ray photoelectron spectroscopy. Crystallinity and chemical bonding states of the oxidized surface in the GaN nanowires were strongly dependent on the oxidation temperature. Chemical oxidation reaction occurred upon increasing the temperature, accompanied by the formation of an amorphous Ga2O3 layer at the GaN nanowire surface at 900 ∘C. The XPS analyses provided further evidence supporting the change in the chemical bonding states with increasing oxidation temperature.