An ultraviolet photodetector based on In2O3/β-Ga2O3 heterojunction

As a wide-bandwidth semiconductor ultraviolet (UV) photodetector (PD), Ga2O3-based UVPDs suffer from a low light-to-dark rejection ratio due to its high dark current. In this study, an UVPD with the In2O3/Ga2O3 heterojunction was successfully achieved and prescribed two steps: the preparation of Ga2O3 and In2O3 ethanol solutions using a hydrothermal method and the deposition of the two materials by spin-coating. Light-dark current tests showed a responsivity of 29.3 A/W at 250 nm and 360 nW/cm2, corresponding to an EQE and D* of 14,500 % and 3.57 x 1012 Jones, and the composite device has a light-to-dark rejection ratio of 4264 compared to that of 208 for the pure Ga2O3 device. And the response recovery times of the devices were 1.41 s and 1.64 s. The good performance of the composite device may be attributed to the depletion layer in the heterojunction in the dark state which effectively reduces the dark current and the desorption of the adsorbed oxygen on the surface of the In2O3 under irradiation. This study provides a potential method for fabricating high-performance UVPD.