One-Dimensional Wide-Bandgap Semiconductor β-Ga2O3 Nanorods for High-Performance Solar-Blind Ultraviolet Photodetectors

Abstract

Solar-blind ultraviolet photodetectors require wide-bandgap materials that can be synthesized through simple and scalable processes. In this work, we demonstrate the controlled growth and defect engineering of β-Ga₂O₃ nanorod films for high-performance detection. Nanorods were synthesized on SiO₂/Si substrates by low-pressure chemical vapor deposition using gallium and oxygen, followed by post-growth oxygen annealing. Structural characterization confirms a highly crystalline monoclinic β phase, and surface chemistry analysis shows that the vacancy-related O 1s component is significantly reduced after annealing. Under 254 nm illumination, metal–semiconductor–metal photodetectors based on annealed nanorods deliver a dark current on the order of 10^-10 A, a photo-to-dark current ratio up to 6 × 10³, and fast rise/decay times of 0.30/1.61 s. These performance enhancements are attributed to effective vacancy passivation, which reduces free-carrier background, mitigates trap-assisted recombination, and improves carrier transport in the nanorod film. Overall, this work establishes LPCVD combined with oxygen annealing as a cost-effective and scalable route to β-Ga₂O₃-based solar-blind photodetectors and provides practical insight into defect engineering strategies for wide-bandgap oxide semiconductors.