High-responsivity self-powered photoelectrochemical solar-blind ultraviolet detector based on (104)-oriented Ga2O3 nanorods

As an ultrawide-bandgap semiconductor, Ga 2 O 3 is highly promising for solar-blind ultraviolet detection. Traditional preparation methods are often complicated and costly. In this study, α-Ga 2 O 3 nanorods were synthesized via a hydrothermal method and employed to construct a photoelectrochemical ultraviolet PD (PEC UV PD). We investigated the influence of hydrothermal parameters on the Ga 2 O 3 thin films. It was observed that extending the hydrothermal reaction time led to an increase in film thickness, whereas elevating the precursor concentration resulted in a reduction in nanorod dimensions. Notably, the introduction of ammonia induced preferential orientation of the nanorods. On the basis of these findings, a Ga 2 O 3 -based PEC PD with a preferential (104) crystal-plane orientation was successfully fabricated, demonstrating excellent solar-blind detection performance. Under 267 nm deep ultraviolet light, it achieved a maximum responsivity (R) of 27.8 mA W⁻¹ and detectivity (D*) of 2.80 × 10¹⁰ Jones, with a solar-blind to near-ultraviolet rejection ratio (R 267nm /R 365nm ) of 11,949. The rise time (τᵣᵢₛₑ) was 36.2 ms, and the delay time (τ delay ) was 20.1 ms. By combining experiments with density functional theory (DFT) calculations, the study indicates the (104) surface facilitates H₂O adsorption, enhancing the oxidation reaction at the PEC PD photoanode-electrolyte interface. This work offers a new approach for developing cost-effective, high-performance solar-blind ultraviolet detectors.