Tunable Ga2O3 solar-blind photosensing performance via thermal reorder engineering and energy-band modulation

As an ultra-wide bandgap semiconductor, gallium oxide (Ga₂O₃) has been extensively applied in solar-blind photodetectors (PDs) owing to the absorbance cut-off wavelength of shorter than 280 nm, and the optimized technologies of detection performance is seriously essential for its further usages. Herein, a feasible thermal reorder engineering method was performed through annealing Ga₂O₃films in vacuum, O₂and oxygen plasma atmospheres, realizing to tune solar-blind photosensing performance of Ga₂O₃PDs. Thermal treatment, in fact a crystal reorder process, significantly suppressed the noise in Ga₂O₃-based PDs and enhanced the photo-sensitivity, with the dark current decreasing from 154.63 pA to 269 fA and photo-to-dark current ratio magically raising from 288 to 2.85 × 10⁴. This achievement is dependent of energy-band modulation in Ga₂O₃semiconductor, that is certified by first-principles calculation. Additionally, annealing in oxygen atmospheres notably reduces the concentration of oxygen vacancies in the surface of films, thereby improving the performance of the PDs; the oxygen vacancy is extremely concerned in oxide semiconductors in the view of physics of surface defects. In all, this work could display a promising guidance for modulating the performance of PDs based on wide bandgap oxide semiconductor, especially for hot Ga₂O₃issue.