High performance solar-blind deep ultraviolet photodetectors via β-phase (In0.09Ga0.91)2O3 single crystalline film

Abstract

We successfully fabricate a high performance β-phase (In0.09Ga0.91)2O3 single-crystalline film deep ultraviolet (DUV) solar-blind photodetector. The 2-inches high crystalline quality film is hetero-grown on the sapphire substrates using the plasma-assisted molecular beam epitaxy (PA-MBE). The smooth InGaO single crystalline film is used to construct the solar-blind DUV detector, which utilized an interdigitated Ti/Au electrode with a metal–semiconductor–metal structure. The device exhibits a low dark current of 40 pA (0 V), while its UV photon responsivity exceeds 450 A/W (50 V) at the peak wavelength of 232 nm with illumination intensity of 0.21 mW/cm2 and the UV/VIS rejection ratio (R 232 nm/R 380 nm) exceeds 4 × 104. Furthermore, the devices demonstrate ultrafast transient characteristics for DUV signals, with fast-rising and fast-falling times of 80 ns and 420 ns, respectively. This excellent temporal dynamic behavior can be attributed to indium doping can adjust the electronic structure of Ga2O3 alloys to enhance the performance of InGaO solar-blind detectors. Additionally, a two-dimensional DUV scanning image is captured using the InGaO photodetector as a sensor in an imaging system. Our results pave the way for future applications of two-dimensional array DUV photodetectors based on the large-scale InGaO heteroepitaxially grown alloy wide bandgap semiconductor films.