Highly responsive and stable self-powered solar-blind photodetectors based on Sn doped β-Ga2O3 nanorod arrays

Abstract

β-Ga₂O₃ possesses a suitable bandgap (4.4–4.9 eV), excellent optical properties, and stable physicochemical characteristics, making it one of the most viable materials for fabricating solar-blind ultraviolet devices. However, the large bandgap generally results in poor electrical conductivity and low carrier mobility, which in turn diminish its photoresponsivity and response speed. In this work, we demonstrate a Sn doped β-Ga₂O₃ nanorod array synthesized via a simple hydrothermal method, which exhibits significantly enhanced solar-blind ultraviolet optoelectronic properties. Under 254 nm ultraviolet light illumination with an intensity of 200 μW cm⁻², the fabricated Sn doped β-Ga₂O₃ self-powered photodetector exhibits a high photoresponsivity of 63.79 mA W⁻¹ at a bias voltage of 0 V, yielding an I_light/I_dark ratio of 1772 and an external quantum efficiency of 31.20%. Meanwhile, the response times are shortened from 5.22 s rise time and 1.03 s decay time for pure β-Ga₂O₃ to 1.01 s and 0.19 s for Sn doped β-Ga₂O₃, respectively. Moreover, no obvious photoresponsivity decay is observed for the Sn doped β-Ga₂O₃ photodetector for a total of 137 complete turn on/off cycles, demonstrating excellent stability and repeatability. This work presents an effective hydrothermal doping approach to boost the optoelectronic performance of β-Ga₂O₃, offering a promising strategy for the fabrication of solar-blind ultraviolet detectors.