Structural and optical evolution of Ga2O3/glass thin films deposited by radio frequency magnetron sputtering

• Structural and optical evolution of Ga2O3 thin films was investigated.
• Initial amorphous films evolved into surface humps and non-stoichiometric nanowires.
• Surface humps and nanowires induce variation of the bandgap and the refractive index.

We investigated the structural and optical evolution of Ga2O3 thin films on glass substrates deposited using radio frequency magnetron sputtering. Initially, amorphous Ga2O3 thin film is grown, and then, surface humps and nanowire (NW) bundles are gradually formed as the film thickness increases. The surface humps are Ga-rich and provide nucleation sites for NWs through a self-catalytic vapor–liquid–solid mechanism with self-assembled Ga droplets. Both the surface humps and the NWs induce variation of the optical properties such as the optical bandgap and refractive index by absorbing light in the ultraviolet region.