SbSI Whisker/PbI2 Flake Mixed-Dimensional van der Waals Heterostructure for Photodetection
Here we report for the first time van der Waals (vdW) heterostructure formed from individual single crystal SbSI whisker and individual PbI2 flake for photodetection. Benefiting from millimeter-sized whisker and flake, we take advantages of the flexibility of operation and vdW junction interface between SbSI and PbI2. This mixed-dimensional heterostructure is used as an optoelectronics platform due to the larger light-harvesting cross section than the individual material. It generates photocurrent to broaden the spectral response range. Two-dimensional (2D) material acts as a current collector while single crystal whisker material acts as current channel. Compared with individual SbSI device, vdW heterojunction devices can achieve a lower dark current. As a result, our SbSI-PbI2 photodetector exhibits a responsivity up to 26.3 mA•W-1 and shows fast response speed of ~ 12 ms. Large-area growth and scalable approaches lead to efficient transfer strategy and heterostructure assembly. These investigations will broaden our fundamental knowledge of vdW heterostructures. This mixed-dimensional vdW heterostructure presupposes new opportunities for basic research of micro/nano-optoelectronic.