Synthesis of β-Ga2O3 nanowires on sapphire substrates using pulsed laser deposition with metal catalysts

Using the pulsed laser deposition method, we investigated the fabrication and properties of β-Ga2O3 nanowires on sapphire substrates with various metal catalysts. Although most previous research has focused on growing Ga2O3 nanowires using Au and Ag catalysts, there has been limited investigation into other metal catalysts. Under the growth conditions employed in this study, β-Ga2O3 nanowires were successfully grown on sapphire substrates using Au, Ag, Cu, Ni, and Ti catalysts. The morphology and growth rates of the nanowires varied significantly depending on the type of metal catalyst and substrate. For Au, Ag, and Cu catalysts, the primary growth mechanism of the β-Ga2O3 nanowires was identified as the vapor–liquid–solid process, whereas for Ni and Ti catalysts, growth was predominantly governed by the vapor–solid mechanism. In contrast, under identical growth conditions, metals such as Sn and Cr failed to act as effective catalysts for nanowire growth due to their inability to sustain catalytic activity at the given temperature. Furthermore, the optical properties of the β-Ga2O3 nanowires were found to vary with the type of catalyst used. This study elucidates the correlation between the feasibility of nanowire growth, the resulting nanowire characteristics, and the properties of the metal catalysts, such as their melting points and eutectic points with Ga, through analysis of the phase diagram.