Self-powered sensitive and stable UV-visible photodetector based on GdNiO3/Nb-doped SrTiO3 heterojunctions

Abstract

The properties of perovskite nickelates are very sensitive to their oxygen content, which allows us to tune their electronic structures by varying the oxygen partial pressure during film deposition. Under the optimized condition, we have obtained GdNiO3 films that are sensitive to a wide spectrum of light. By combining the GdNiO3 film with Nb-doped SrTiO3 to form a heterojunction, we design a self-powered photodetector with high sensitivity toward light with a wavelength between 650 nm and 365 nm. Under 365 nm illumination (50 μW/cm2), the device shows a responsivity of 0.23 A/W at 0 V bias, comparable to or even better than the ultraviolet photodetectors made of semiconductor materials such as GaN or ZnO. The photo-dark ratio can be close to 103 when the power light density reaches 0.6 mW/cm2. Moreover, the device performance is very stable without any decay after 6 months.