High‐Performance Photoinduced Tunneling Self‐Driven Photodetector for Polarized Imaging and Polarization‐Coded Optical Communication based on Broken‐Gap ReSe2/SnSe2 van der Waals Heterojunction

Abstract Novel 2D materials with low‐symmetry structures exhibit great potential applications in developing monolithic polarization‐sensitive photodetectors with small volume. However, owing to the fact that at least half of them presented a small anisotropic factor of ≈2, comprehensive performance of present polarization‐sensitive photodetectors based on 2D materials is still lower than the practical application requirements. Herein, a self‐driven photodetector with high polarization sensitivity using a broken‐gap ReSe 2 /SnSe 2 van der Waals heterojunction (vdWH) is demonstrated. Anisotropic ratio of the photocurrent ( I max / I min ) could reach 12.26 (635 nm, 179 mW cm −2 ). Furthermore, after a facile combination of the ReSe 2 /SnSe 2 device with multilayer graphene (MLG), I max / I min of the MLG/ReSe 2 /SnSe 2 can be further increased up to13.27, which is 4 times more than that of pristine ReSe 2 photodetector (3.1) and other 2D material photodetectors even at a bias voltage. Additionally, benefitting from the synergistic effect of unilateral depletion and photoinduced tunneling mechanism, the MLG/ReSe 2 /SnSe 2 device exhibits a fast response speed (752/928 µs) and an ultrahigh light on/off ratio (10 5 ). More importantly, MLG/ReSe 2 /SnSe 2 device exhibits excellent potential applications in polarized imaging and polarization‐coded optical communication with quaternary logic state without any power supply. This work provides a novel feasible avenue for constructing next‐generation smart polarization‐sensitive photodetector with low energy consumption.