Fabrication and Ultraviolet Response Characteristics of All-Oxide Bi2O3/Ga2O3 Heterojunction

Heterojunctions are commonly used in optoelectronic devices to improve device performance. However, interface defects and lattice mismatch often hinder carrier transport and reduce efficiency, emphasizing the need for further exploration of diverse heterojunction structures. In this study, a heterojunction device constructed from Bi2O3 and Ga2O3 is demonstrated. The microstructures and photoelectrical properties of Bi2O3 and Ga2O3 thin films were investigated. Bi2O3 and Ga2O3 thin films show a bandgap of 3.19 and 5.10 eV. The Bi2O3/Ga2O3 heterojunction-based device demonstrates rectification characteristics, with a rectification ratio of 2.72 × 103 at ±4.5 V and an ON/OFF ratio of 1.07 × 105 (4.5/−3.9 V). Additionally, we fabricated a sandwich-structured photodetector based on the Bi2O3/Ga2O3 heterojunction and investigated its ultraviolet photoresponse performance. The photodetector exhibits low dark current (0.34 pA @ −3.9 V) and fast response rise/fall time (<40/920 ms). This work offers important perspectives on the advancement of large-area, low-cost, and high-speed Bi2O3 film-based heterojunction photodetectors.