Self-Powered β -Ga 2 O 3 Solar-Blind Photodetector Based on the Planar Au/Ga 2 O 3 Schottky Junction

In this paper, asymmetric interdigital Ti and Au electrodes have been successfully patterned on the β -Ga 2 O 3 films which are prepared by metal-organic chemical vapor deposition. Both photoconductive and photovoltaic modes have been observed under ultraviolet illumination, respectively. The device exhibits a low current density of 0.32 nA cm −2 at 20 V in dark condition. As the 254 nm illumination intensity increases above 400 μ W cm −2 , the device exhibits obvious self-powered characteristics with a responsivity of 0.4 mA W −1 , providing a specific detectivity of 1.8 × 10 12 Jones, a fast response time ( τ d = 50 ms), and a high photo-to-dark current ratio of ∼10 5 . As the positive bias was applied to Au/Ga 2 O 3 contact, the photodetector presents an improved performance with a responsivity of ∼0.3 A W −1 and a specific detectivity of 2.2 × 10 14 Jones at −10 V, ultra-high photo to dark ratio (2 × 10 6 ∼ 9 × 10 7 ), and a response time of 160 ms. In one word, the simple structured, self-powered characteristics and decent performances of the detector suggest promising applications in solar-blind ultraviolet photoelectronic technology in multiple areas.