Comprehensive enhancement of ZnGa2O4-based solar blind photodetector performance by suppressing defects in oxygen-rich atmosphere

ZnGa2O4 is a potential candidate material for next-generation solar-blind UV photodetectors (PDs) owing to its intrinsically wide bandgap and various favorable physical properties. The photoelectric properties of metal oxides are susceptible to oxygen. This study investigated the effect of oxygen flow on the properties of ZnGa2O4 thin films. Furthermore, photovoltaic devices with Au as Schottky contacts were fabricated to compare the performance. The ZnGa2O4 films grown in an oxygen-rich atmosphere exhibit better crystallinity and fewer oxygen vacancies than those grown in an oxygen-poor atmosphere, and the corresponding device demonstrates excellent performance parameter at a bias voltage of 10 V: a responsivity (R), external quantum efficiency (EQE) and detectivity (D*) up to 15.62 A/W, 7626%, ∼1015 Jones, respectively. Additionally, the suppression of oxygen vacancies prevents persistent photoconductivity under low light irradiation. The device possesses satisfactory rise/decay times of 0.125/0.025 s and maintains excellent stability and repeatability. Our study confirms that sputtering in an oxygen-rich atmosphere is an effective strategy for producing ZnGa2O4 thin films that can be applied for fabricating ZnGa2O4 solar-blind PDs with excellent comprehensive performance.