【Device Papers】Performance enhancement and emergence of self-powered in amorphous Ga₂O₃ solar-blind photodetectors via controlled reducing-environment annealing

      Researchers from the Indian Institute of Technology Ropar have published a dissertation titled "Performance enhancement and emergence of self-powered in amorphous Ga₂O₃ solar-blind photodetectors via controlled reducing-environment annealing" in Applied Surface Science.

Abstract

      Solar-blind photodetectors (SBPDs) based on a-Ga₂O₃ have attracted considerable interest due to their room-temperature growth and scalability. However, device performance is often constrained by structural disorder and defect-related carrier trapping. Post annealing under different environments has been widely adopted as an effective approach to mitigate structural disorder and regulate defects. Herein, we investigate the effect of post-annealing under a controlled sulfur-rich reducing environment on the structural, chemical, and optoelectronic properties of a-Ga₂O₃-based SBPD. Structural analysis reveals a phase transformation from a-Ga₂O₃ to polycrystalline β-Ga₂O₃ at optimum sulfur content, while excessive sulfur results in the formation of an ultrathin Ga₂S₃ surface layer. These results reveal that optimal sulfur annealing promotes crystallization and regulates oxygen vacancies. The device annealed with an optimal sulfur amount exhibits a ∼26-fold enhancement in responsivity compared to the unannealed device while maintaining a comparable response time. Notably, this optimized device also demonstrates stable zero-bias photoresponse with a high photo-to-dark current ratio of ∼4.1 × 10⁴ and a fast fall time of 150 ms, along with excellent long-term stability under ambient conditions. These results establish a controlled reducing-environment annealing as a simple and effective strategy to enhance the performance of a-Ga₂O₃-based solar-blind photodetectors and enable self-powered operation.

DOI：

https://doi.org/10.1016/j.apsusc.2026.167103