RF-Sputtered β-Ga₂O₃ Thin Films for Solar-Blind UV Detection: Progress, Challenges, and Future Perspectives

This review presents a comprehensive and thorough evaluation of recent developments in physical vapour deposition (PVD) radiofrequency (RF)-sputtered β-Ga₂O₃ thin-film-based solar-blind ultraviolet (UV) photodetectors (SB-UVPDs), emphasizing their potential for next-generation optoelectronic applications. The review highlights different photodetector architectures, the performance characteristics of SB-UVPDs, and an overview of the attributes of β-Ga₂O₃ that make it a promising wide-bandgap semiconductor for next-generation devices. Additionally, the working principle of the PVD RF magnetron sputtering technique is discussed briefly, with a particular focus on the influence of deposition parameters, including sputtering power, gas pressure, deposition time, target-to-substrate distance, and substrate temperature, on the resulting film's crystallinity and morphology and the optical quality of SB-UVPDs. Moreover, the impact of post-deposition treatments, such as post-annealing and elemental doping, is also discussed here for SB-UVPDs. And finally, the electrical performance characteristics of SB-UVPDs are discussed categorically based on deposition parameters. Overall, this review establishes that PVD RF magnetron sputtering is a highly versatile and controllable technique for fabricating high-quality β-Ga₂O₃ thin film-based SB-UVPDs. By carefully optimizing deposition and post-processing parameters, the optoelectronic performance of β-Ga₂O₃-based SB-UVPDs can be effectively tuned, enabling their integration into next-generation high-performance optoelectronic and photonic systems.