Boosting the responsivity of β-Ga₂O₃ metal-semiconductor-metal solar-blind photodetectors through oxygen-related defect states

Achieving high responsivity is essential for advancing solar-blind photodetectors (SBPDs) in applications such as wireless communication and fire warning systems. In this study, we investigate metal-semiconductor-metal SBPDs based on β-Ga2O3 epitaxial films grown on sapphire substrates by metal-organic chemical vapor deposition at different temperatures. Structural and spectroscopic analyses indicate that growth temperature modulates oxygen-related defect states in β-Ga2O3 films, which correlate with changes in responsivity through defect-assisted photoexcitation processes. Notably, the SBPD fabricated from a Ga2O3 film grown at 900 °C exhibited a responsivity of 4.2⋅104 A/W, a detectivity of 1.2⋅10¹³ Jones, and an exceptional external quantum efficiency of 2.1⋅10⁷%. These findings highlight the important role of oxygen-related defect states in optimizing the photoresponse of β-Ga2O3 based SBPDs.