Self-powered deep-ultraviolet detection via high-photovoltage open-circuit mode in nanoporous Ga2O3 thin films

초록

Detection of ultraviolet C (UVC) radiation has enabled state-of-the-art applications, including flame alarming, missile tracking, partial-discharge detection, and wireless communication. Although wide-bandgap Ga2O3 is an excellent candidate for solar-blind UVC detection, the requirement for complex and ultrahigh-vacuum fabrication processes remains an obstacle to the industrial and cost-effective production of high-performance Ga2O3-based UVC detectors. Additionally, light scattering on the photoabsorber surface causes a loss of incident light, leading to poor device sensitivity for weak-intensity UV detection. To address these issues, we propose a facile process for preparing a highly nanoporous Ga2O3 thin film as an efficient photoabsorber layer using a sol-gel spin-coating method. The intrinsic porosity of the Ga2O3 film enhances the UVC absorption coefficient by up to 70% compared with a compact Ga2O3 control film prepared using an analogous sol-gel spin-coating process. As a result, the nanoporous Ga2O3-based photodetector (PD) exhibits an outstanding on/off ratio (>10(3)) and a large open-circuit voltage (V-OC = 0.82 V) under 254 nm UV illumination without a power supply. As a proof of concept, the PD can be conveniently connected to a simple digital multimeter to monitor weak-intensity UVC light without interference from solar light.

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