Realization of high-performance solar-blind UV detector via a ZrO₂/Ga₂O₃/LaO_x p-i-n heterostructure

Solar-blind ultraviolet (UV) detection, operating in the 200-280 nm wavelength range, is of critical importance for applications such as missile warning and secure communication due to the inherent absence of solar background radiation. While β-Ga₂O₃ is a promising material for inherent solar-blind detection, conventional photoconductive detectors based on it suffer from low responsivity and slow response speed. This work presents a self-powered, vertical heterojunction solar-blind photodetector designed to overcome these limitations. The device features an innovative n-ZrO₂/β-Ga₂O₃/p-LaO_x ternary thin-film structure that forms a p-i-n junction with nearly ideal band alignment, creating a strong built-in electric field for efficient carrier separation. A high-transmittance silver nanowire (AgNWs) network serves as the top window electrode, enabling high photon flux. The fabricated detector operates at 0 V bias, achieving a responsivity of 5.2 mA W^-1, a specific detectivity (D*) of 2.59 × 10¹² Jones, and a photo-to-dark current ratio exceeding 4.1 × 10⁴ under 254 nm illumination. Furthermore, the response speed is significantly enhanced, with 0.36/0.58 s under lower illumination (20 μW cm^-2) and 56/150 ms under higher intensity (350 μW cm^-2). The detector's exceptional performance was further validated through a solar-blind UV imaging system, where it successfully reconstructed clear patterns with high contrast and a clean background, demonstrating its potential for practical imaging applications. This work provides a novel device architecture for high-performance, self-powered solar-blind photodetection and offers valuable insights for the design of wide-bandgap semiconductor optoelectronic devices.