Performance Enhancement of Ga2O3 Solar-Blind UV Photodetector by the Combination of Oxygen Annealing and Plasma Treatment

Monoclinic Ga2O3 (β-Ga2O3) meets the demand of intrinsic solar-blind photodetection for various applications. Currently, it is still very challenging to realize excellent β-Ga2O3 solar-blind photodetectors. Here, we demonstrated a high-performance solar-blind ultraviolet (UV) photodetector based on β-Ga2O3 thin films by combining high-temperature oxygen annealing and oxygen plasma treatment. A high normalized photo-to-dark current ratio of 1.3 × 1012 W–1, a large rejection ratio (Rpeak/R400) of 8.6 × 106, and fast rise/decay times of 0.6/0.5 s have been obtained from the annealed & plasma-treated β-Ga2O3 photodetector. Moreover, the effects of the combination of oxygen annealing and oxygen plasma treatment on the properties of β-Ga2O3 films and their photodetectors were investigated. The results indicated that the improved solar-blind photodetection performance can be attributed to the reduction of the oxygen vacancy defects and the modification of the surface states of the Ga2O3 films after oxygen annealing and plasma treatment in sequence. Our findings in this work provides a potential way to improve the performance of Ga2O3 film-based solar-blind UV photodetectors.