Self-powered ultraviolet photodetectors based on match like quasi one-dimensional n-TiO2/p-NiO core-shell heterojunction arrays with NiO layer sputtered at different power

Self-powered ultraviolet photodetectors (UV PDs) are urgently needed for portable, sustainable, maintenance free, and long-term applications. The geometry of device structure and interface energy band arrangement will affect the photoresponse performance of heterojunction PDs. In this work, a self-powered UV PDs based on match like quasi one-dimensional TiO2/NiO core-shell heterojunction arrays is fabricated by RF magnetron depositing NiO over TiO2 NRs. By controlling sputtering power, NiO(50 W)/TiO2, NiO(80 W)/TiO2 and NiO(120 W)/TiO2 devices were obtained. Under self-powered mode, the performance of PDs is carefully explored and the NiO (80 W)/TiO2 device displays a large photocurrent (1.2 ×10−6 A) and a high responsivity (74 mA/W) at 380 nm light irradiation. The results presented in this work suggest that a comprehensive consideration and a reasonable optimization of interface energy level structure and carrier transmission is the important for developing high-performance self-powered UV PDs.