High-performance β-Ga2O3 solar-blind UV/X-ray photodetector enhanced by oxygen vacancy modulation
β-Ga2O3 metal-semiconductor-metal photodetectors were fabricated on MOCVD-grown films with controlled oxygen vacancy content via the Foxy/FTEGa precursor ratio. Increasing Foxy/FTEGa improved crystallinity and reduced oxygen vacancy concentration. The optimal device exhibited a dark current of 30.9 fA, a photo-to-dark current ratio of 8.7 × 10^8, and a responsivity of 237 A W−1 under 254 nm solar-blind ultraviolet illumination, with rise/decay times of 155/34 ms. Under X-ray irradiation, the detector achieved a sensitivity of 10,736 μC cm−2 Gy_air−1, 477 times higher than conventional a-Se detectors, and maintained stable performance during prolonged X-ray exposure. Energy-band analysis under different photoinjection conditions clarified the distinct roles of oxygen vacancies in SBUV and X-ray photoresponse, linking defect density to responsivity and response speed. These findings provide a mechanistic framework for engineering Ga2O3-based detectors with optimized comprehensive performance for astronomical imaging, medical diagnostics, and harsh-environment applications.