Direct conversion of β-Ga2O3 thin films to β-Ga2O3 nanowires by annealing in a hydrogen atmosphere

We report the annealing process of Au/β-Ga2O3 thin films in a hydrogen atmosphere leading to a direct conversion of β-Ga2O3 thin films to β-Ga2O3 nanowires (NWs). Annealing in a hydrogen atmosphere results in the evaporation of β-Ga2O3 thin films, which are subsequently converted to β-Ga2O3 NWs through the vapor-liquid-solid (VLS) process assisted by Au nanocrystals. The VLS growth starts at 600 °C and progresses with increase in the annealing temperature to 800 °C. β-Ga2O3 NWs are formed on the surface of the host β-Ga2O3 thin films, resulting in the formation of a homogeneous β-Ga2O3 NW/β-Ga2O3 thin film structure. Based on structural analyses using X-ray diffraction, scanning electron microscopy, and transmission electron microscopy, a possible mechanism for the growth of β-Ga2O3 NWs is presented.