Boosting Solar Blind UV Detector by Constructing Enhanced-Mode MOS Field-Effect Transistors Based on β-Ga2O3 Film

A three-terminal metal-oxide field-effect transistor (MOSFET) switching device is an exciting solution for achieving low dark currents and high photocurrents. The back-gated structure effectively ensures the full exposure of the top layer of beta-Ga2O3 to incident light, thereby maximizing the collection of detection information. In this study, we achieved an enhanced mode back-gated MOSFET based on beta-Ga2O3 film for solar-blind UV detection applications with a film thickness of 80 nm. Compared to the traditional two-terminal structure, the MOS device's channel was fully depleted via gate modulation, resulting in a further reduction of the intrinsic dark current. Meanwhile, the photoconductivity performance is greatly improved through the dual regulation mode of light intensity and gate voltage. As a consequence, the back-gated MOS photodetector (PD) shows a much superior photoelectric performance, characterized by an ultralow dark current of 0.018 pA and a high photo-to-dark current ratio (PDCR) of 6.7 x 104. Our findings suggest that utilizing an E-mode back-gated MOS structure could serve as a highly efficient and energy-saving approach for the development of gallium oxide (Ga2O3) PDs in solar-blind UV applications.