Self-Powered p-NiO/n-Ga₂O₃ Heterojunction Solar-Blind Photodetector With Record Detectivity and Open Circuit Voltage

Self-powered solar-blind photodetector (SBPD) promises potential applications that urgently need portability and low-power consumption. Herein, an ultrasensitive self-powered p-n heterojunction SBPD based on amorphous NiO and single crystal Ga2O3 has been reliably achieved. The device exhibits a high photo-to-dark-current ratio of ${3}\times {10}^{{6}}$ , ultrahigh responsivity ( ${R}$ ) of 5 A/W, and specific detectivity of ${1.6}\times {10}^{{14}}$ Jones under 254 nm illumination at 0 V, with a solar-blind/visible rejection ratio ( ${R}_{\text {254 nm}}/{R}_{\text {460 nm}}$ ) of ${2}\times {10}^{{4}}$ . Notably, the open circuit voltage can reach 1.3 V and the response speed is significantly less than 1 ms. The comprehensive performance of the device exceeds most reported state-of-the-art Ga2O3 self-powered SBPDs, which is mainly attributed to amorphous NiO/crystalline Ga2O3 vertical junction structure with low-defect interface and strong built-in electric field. This work provides novel design strategies for the future development of high-performance self-powered photodetector.