High-Performance Ultraviolet Photodetectors Based on Ga2O3/GaN Gradient Heterojunction

Gallium nitride (GaN)-based ultraviolet (UV) photodetectors (PDs) have attracted widespread attention due to their potential applications in UV curing, environmental monitoring, and other fields. However, the GaN PDs generally exhibit low responsivity due to poor carriers’ separation efficiency. Gallium oxide (Ga₂O₃)/GaN heterostructure is an ideal material for fabricating high-performance UV PDs due to appropriate bandgap and differences in energy band. In this regard, we have demonstrated the Ga₂O₃/GaN gradient heterostructure UV PDs with high photoresponse performance. The Ga₂O₃ layer was prepared by magnetron sputtering combined with thermal annealing (TA). TA promotes not only the crystalline quality of the Ga₂O₃ layer but also the transformation of abrupt Ga₂O₃/GaN heterojunctions into gradient Ga₂O₃/GaN heterojunctions. The as-fabricated Ga₂O₃/GaN heterostructure UV PD exhibits a high responsivity of 178.9 (254 nm) and 213.3 A/W (365 nm), with the corresponding detectivity of 3.0 × 10¹⁵ and 3.6 × 10¹⁵ Jones. This work provides a promising pathway toward UV PDs with a high responsivity range from UV-A to UV-C bands.