Postgrowth Annealing Strategy for β -Ga 2 O 3 on Sapphire Solar Blind Photodetectors With High Detectivity and Fast Response

Despite extensive efforts towardβ-Ga2O3-based solar-blind ultraviolet (UV) photodetectors, further performance improvement remains challenging due to intrinsic defect limitations and material-quality constraints. In this work, we demonstrate high-performance solar-blind photodetectors using heteroepitaxialβ-Ga2O3films grown on sapphire and systematically elucidate the critical role of high-temperature annealing in overcoming these bottlenecks. Asignificant reduction in oxygen-vacancy-related defects within theβ-Ga2O3heteroepitaxial layers was confirmed by X-ray photoelectron spectroscopy (XPS). Photodetectors annealed at1100~∘C achieve a responsivity of 14 151A/W and a detectivity of1.83× 10^16Jones at 10V under 254nm illumination, representing fivefold and sixfold enhancements relative to unannealed devices. The annealed films exhibit a carrier lifetime of 0.13s, much faster than the reported Ga2O3photodetectors with similar responsivity. This work demonstrates a viable approach to achieving both high gain and fast response inβ-Ga2O3photodetectors, providing a reliable strategy and key insights into defect engineering for advancing wide bandgap optoelectronics.