Growth of β-gallium oxide nanostructures by the thermal annealing of compacted gallium nitride powder

Various β-gallium oxide (β-Ga2O3) nanostructures such as nanowire, nanobelt, nanosheet, and nanocolumn were synthesized by the thermal annealing of compacted gallium nitride (GaN) powder in flowing nitrogen. We suggest that Ga2O3 vapor might be formed by the reaction of oxygen with the gaseous Ga formed by GaN decomposition. The Ga2O3 vapor diffuses into voids derived by compacting GaN powder and is supersaturated there, resulting in the growth of Ga2O3 nanostructures via the vapor–solid (VS) mechanism. Ga2O3 plate-like hillocks and nanostructures were also grown on the surface of a c-plane sapphire placed on the GaN pellet.