Perovskite Stannate Heterojunctions for Self-Powered Ultraviolet Photodiodes Operated in Extreme Environments

High-performance UV photodetectors call for sensitive and energy-efficient signal detection in extreme environments. To satisfy the requirement of a UV detection without an external power consumption, self-powered UV photodetectors must be realized by an optimal combination of heterostructure with maximum built-in potential using novel wide-bandgap materials. Here, self-powered UV photodiodes are designed via the band engineering of a wide-bandgap Sr(Sn,Ni)O-3/BaSnO3 heterojunction for the first time. Based on the theoretical concept of acceptor doping by Ni substitution in SrSnO3, remarkably, this heterojunction with a conduction band offset of 0.94 eV shows strong nonlinear electrical characteristics with extremely low I-dark (approximate to 100 fA) owing to the spatial gradient of the potential barrier across the interfaces, outstanding photo-to-dark current ratio (>10(7) at 25 degrees C and > 10(4) at 300 degrees C), and high stability under various extreme conditions upon UV illumination even without external bias (V = 0 V). This study suggests a novel strategy that utilizes band engineering to maximize sensitivity and minimize energy consumption in harsh environments for UV imaging using the newly discovered wide-bandgap semiconductors.