Advances in β -Ga2O3-based PN junctions for solar-blind ultraviolet photodetectors

β-Ga2O3, as a semiconductor material possessing exceptional properties such as an ultrawide bandgap and a high breakdown electric field, has demonstrated significant application potential in solar-blind ultraviolet photodetectors (SBUV) through its PN junction. This review focuses on the current research status of β-Ga2O3-based PN junctions and their corresponding SBUV. It begins by elucidating the crystal structure, electronic structure, and the energy band evolution before and after the formation of β-Ga2O3-based PN junctions, outlining the core operating principle of SBUV based on the generation and directional transport of photogenerated carriers. Subsequently, the types of p-type semiconductor materials compatible with β-Ga2O3 are systematically summarized, along with their respective advantages and disadvantages, followed by a detailed introduction to mainstream fabrication techniques. The review then provides a focused analysis of recent research progress on four major categories of β-Ga2O3-based PN junctions: those incorporating two-dimensional materials, elemental doping, covalent compounds, and metal oxides. Finally, the application status of such detectors in various fields, including flame detection and fire warning, ultraviolet communication and sensing, scientific research and medical applications, and high-voltage corona discharge detection, is summarized. Further prospects were given on the challenges and potential solutions for the future development of β-Ga2O3 materials. This review aims to provide a reference for further research and industrial applications of β-Ga2O3-based SBUV.