Ga 2 O 3 Solar-Blind Deep-Ultraviolet Photodetectors with a Suspended Structure for High Responsivity and High-Speed Applications

The wide-bandgap semiconductor material Ga 2 O 3 exhibits great potential in solar-blind deep-ultraviolet (DUV) photodetection applications, including none-line-of-sight secure optical communication, fire warning, high-voltage electricity monitoring, and maritime fog dispersion navigation. However, Ga 2 O 3 photodetectors have traditionally faced challenges in achieving both high responsivity and fast response time, limiting their practical application. Herein, the Ga 2 O 3 solar-blind DUV photodetectors with a suspended structure have been constructed for the first time. The photodetector exhibits a high responsivity of 1.51 × 10 10 A/W, a sensitive detectivity of 6.01 × 10 17 Jones, a large external quantum efficiency of 7.53 × 10 12 %, and a fast rise time of 180 ms under 250-nm illumination. Notably, the photodetector achieves both high responsivity and fast response time simultaneously under ultra-weak power intensity excitation of 0.01 μW/cm 2 . This important improvement is attributed to the reduction of interface defects, improved carrier transport, efficient carrier separation, and enhanced light absorption enabled by the suspended structure. This work provides valuable insights for designing and optimizing high-performance Ga 2 O 3 solar-blind photodetectors.