【Device Papers】Gradient Passivation of Oxygen Vacancy Boosts Ga₂O₃ Solar-Blind UV Detector

      Researchers from the National University of Defense Technology have published a dissertation titled "Gradient Passivation of Oxygen Vacancy Boosts Ga₂O₃ Solar-Blind UV Detector" in Advanced Materials Technologies.

Abstract

      Ultra-wide bandgap semiconductor gallium oxide (Ga₂O₃) is rising as a promising candidate for the applications in solar-blind UV detectors, radio frequency devices, and power electronics. However, the randomly distributed oxygen vacancy (V_O) defects result in the disorganized local energy level, limiting the carrier transport and device performance. Here we report the energy level alignment based on the Gradient Passivation of Oxygen Vacancy (GPVO), enabled by the migration of shallower oxygen interstitial defects (O_i) toward Ga₂O₃ film surface, and the recombination of deeper O_i with V_O through vacuum annealing. We construct the gradually increased E_f of Ga₂O₃ film along the direction from surface to bulk, and improve the built-in electric field of Ga₂O₃ vertical Schottky diode. Therefore, we fabricate the Ga₂O₃ Solar-blind UV detectors with enhanced responsivity and specific detectivity of 8.6 A W⁻¹ and 1.5 × 10¹⁵ Jones under 254 nm illumination, at bias voltage of −1.7 V, as well as the shorter response time of 1.04 s/16 ms. Moreover, we report the first 64 × 64 Ga₂O₃ image sensor and demonstrate the solar-blind UV video imaging of complex images.

DOI：

https://doi.org/10.1002/admt.202501970