Zr-Doping Strategy of High-Quality Cu₂O/β-Ga₂O₃ Heterojunction for Ultrahigh-Performance Solar-Blind Ultraviolet Photodetection

β-Ga 2 O 3, as an ultrawide band gap semiconductor, has emerged as the most promising candidate in solar-blind photodetectors. The practical application of β-Ga 2 O 3, however, suffers from intrinsic defects and suboptimal crystal quality within the devices. In this work, high-quality β-Ga 2 O 3 was successfully synthesized by employing the Zr-doping strategy, which has facilitated the development of ultrahigh-performance solar-blind photodetectors based on Cu 2 O/β-Ga 2 O 3 heterostructures. Structural analyses indicate that the strong Zr–O covalent bond effectively stabilizes the material, thereby eliminating oxygen vacancy defects. The Cu 2 O/β-Ga 2 O 3 heterostructure photodetector demonstrates an ultrahigh responsivity and detectivity coupled with an external quantum efficiency. Furthermore, the device exhibits a photocurrent-to-dark current ratio of 3 × 10 5, showcasing its superior capability in detecting low-intensity deep ultraviolet signals, markedly surpassing previous heterostructure ultraviolet photodetectors. These exceptional performances are attributed to the effective elimination of oxygen vacancy defects in β-Ga 2 O 3 and the variation of band alignment at the interface, which facilitate rapid separation of photogenerated electron–hole pairs under reverse bias. This study not only provides an enhanced and easy route to mitigate oxygen vacancy defects in oxide materials but also propels further exploration into the next generation of flexible, high-performance, solar-blind ultraviolet photodetectors.