Amorphous Ga2O3 Schottky photodiodes with high-responsivity and photo-to-dark current ratio

Schottky photodiodes with sputtered amorphous Ga2O3 (a-Ga2O3) and asymmetric electrodes were fabricated for the first time and achieved excellent performances under 254-nm light illumination with the superhigh responsivity of 1021.8 A W−1, high photo-to-dark current ratio of 2.3 × 106, fast rise/decay response time of 144/208 ms, high detectivity of 1.66 × 1016 Jones, and high external quantum efficiency of 5.0 × 105 %. The excellent solar-blind detection performances are suggested to be attribute to the large concentration of oxygen vacancies, the possible photo released carriers from the deep-level acceptors, and the high film uniformity, while the former two contribute to the high photo carrier concentration, and the latter one contributes to high quality Schottky contact to achieve the low dark current. A 10 × 10 array based on these a-Ga2O3 Schottky photodiodes realized the imaging of a “E” character with high contrast. The results give a feasible way to achieve large area, low cost, high contrast, and high detection sensitivity solar-blind imaging.