【Device Papers】Solar-blind β-Ga₂O₃ photodetectors with high detectivity via semimetal Bi contacts

      Researchers from the Hubei University have published a dissertation titled "Solar-blind β-Ga₂O₃ photodetectors with high detectivity via semimetal Bi contacts" in Surfaces and Interfaces.

Abstract

      Solar-blind UV photodetectors based on Ga₂O₃ films possess important potential applications in ozone-hole detection, flame detection and corona detection. However, the performance (detectivity, response time, etc.) of Ga₂O₃-based photodetectors reported so far still lags behind the current commercial devices, due to the metal-induced gap states (MIGS) at the metal–semiconductor interface. Here, by contact engineering, we design an ohmic-contacted photodetector based on semimetal Bi electrodes and single-crystal β-Ga₂O₃ films. The transmission electron microscopy (TEM) shows that the Bi electrode is a layered single-crystal grown on the single-crystal Ga₂O₃ film by van der Waals epitaxy, providing a clean and dangling-bond-free interface. The Bi-Ga₂O₃ photodetector exhibits a high responsivity of 720 A W^-1 and an ultra-high specific detectivity of 4.35 × 10¹⁵ Jones under 254 nm ultraviolet light. More importantly, the device still shows high detectivity at a lower light intensity (6 μW cm^-2). Overall, the high-sensitive Bi/Ga₂O₃/Bi devices have great potential for future commercial solar-blind UV photodetectors.

DOI：

https://doi.org/10.1016/j.surfin.2025.106052