Self-Powered Photodetector Based on Perovskite/Ge Heterojunction with High Responsivity

Self-powered photodetectors (SPDs) are regarded as a new type of photodetectors without external energy sources, exhibiting great potential in the next generation of image sensing, biological detection, and robotics. Here, single crystal CH(NH2)(2)PbBr3 (FAPbBr(3)) perovskite with a low trap density of 1.64 x 10(9) cm(-3) is directly integrated onto single crystal germanium (Ge). The band structure of the heterojunction belongs to type-II alignment type, which is beneficial to the achievement of high responsivity. Therefore, the fabricated Au/FAPbBr3/Ge/Au detector exhibits a high responsivity of 0.33 A W-1, detectivity up to 3.83 x 10(11) Jones and relatively fast decay time of 4.94 ms without external bias under 520 nm laser illumination. In addition, a prototype of an imaging system is set up utilizing the photodetector as a sensing pixel, from which the imaging function is verified. This work demonstrates a facile strategy for designing high-performance SPDs.