Self-Driven Photodetectors Based on Flexible Silicon Nanowires Array Surface-Passivated With Tin-Based Perovskites

Self-driven photodetectors based on flexible silicon nanowire (Si-NW) array have attracted widespread research interests since they can continuously operate without external bias. However, their practical performances are limited due to the high density of intrinsic defects introduced by the chemical etching procedure for the Si-NWs. To address this issue, first ultrathin silicon wafers are etched with a metal-assisted chemical etching method, then flexible Si-NWs are obtained, and finally, a high-performance self-driven photodetector Si/[Si-NWs/FASnBr3]/MoO3/Au, in which Si-NWs are surface passivated with FASnBr3 nanocrystals, is presented. As a result, the responsivity and specific detectivity of the self-driven photodetector reach 0.694 A/W and $2.9\times 10^{{13}}$ Jones, respectively, under $0.8~\mu $ W/cm $^{{2}}~980$ nm illumination at zero bias, with a rising time of 58.552 ms and a falling time of 43.729 ms. The enhanced device performance is mainly due to the improved surface passivating effect on the silicon nanowire surfaces by FASnBr3 nanocrystals. Thus, it provides an efficient method to passivate the surfaces of silicon nanowires, and it is a promising method to enhance the performances of self-driven Si-NW-based photodetectors.