High-Performance Photoinduced Tunneling Self-Driven Photodetector for Polarized Imaging and Polarization-Coded Optical Communication based on Broken-Gap ReSe 2 /SnSe 2 van der Waals Heterojunction.

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.