High sensitivity and fast response self-powered solar-blind ultraviolet photodetector with a β-Ga2O3/spiro-MeOTAD p–n heterojunction

Abstract

Solar-blind ultraviolet (UV) photodetectors are greatly desired in a number of areas in terms of military and civilian purposes, especially self-powered devices driven by the photovoltaic effect. Herein, a solar blind photodetector has been successfully achieved on a spiro-MeOTAD/β-Ga₂O₃ organic–inorganic hybrid construction. The fabricated photodetector can operate with a self-powered mode and shows an obvious photodetection with a narrow spectrum region, exhibiting a high responsivity (65 mA W⁻¹) and a large external quantum efficiency (32%) under low power intensity (∼1 μW cm⁻²) UV illumination, at zero bias. Fortunately, the device shows a fast temporal pulse response (τ_rise ∼ 2.98 μs and τ_decay ∼ 28.49 μs), which is superior to the previously reported Ga₂O₃ based self-powered photodetectors. More importantly, the photodetector can operate stably and shows good repeatability. These excellent performances of the device could be attributed to the pre-existing band alignment of the Ga₂O₃ and spiro-MeOTAD, and are comparable to and/or even higher than those of other self-powered solar-blind UV photodetectors, which indicates that a device configuration based on a Ga₂O₃/spiro-MeOTAD heterojunction is certified as an excellent candidate for a high sensitivity, ultrafast response and self-powered photo-detecting device for solar-blind UV signals.