Polarization‐Sensitive Self‐Powered Photodetector Based on Anisotropic/Isotropic ReS 2 /SnSe 2 Van der Waals Heterojunction

Abstract Polarization‐sensitive photodetectors have garnered significant interest due to their promising applications in navigation, remote sensing, and optical communication. However, conventional polarized light detectors relying on optical filters face challenges due to intricate fabrication and calibration procedures. While structures based on in‐plane anisotropic 2D materials have the potential to offer viable solutions for polarization detection, achieving both low power consumption and high performance remains challenging. Herein, a self‐powered anisotropic/isotropic ReS 2 /SnSe 2 van der Waals (vdWs) heterojunction detector with high‐performance features is constructed. This device exhibits outstanding photovoltaic (PV) performance across a wide spectral range from 405 to 850 nm without bias, featuring excellent responsivity (0.966 A W −1 ) and specific detectivity (1.47 × 10 10 Jones) under 650 nm laser illumination. Moreover, benefiting from the built‐in electric field that promotes carrier separation and extremely low dark current, the device shows fast response time (230/240 µs) with an on/off ratio of up to 10 4 . Furthermore, the ReS 2 /SnSe 2 photodetector demonstrates exceptional polarization encoding performance, with a polarization ratio of 1.56 under 650 nm illumination, opening up new possibilities in optical communication technology development. This research provides a novel and viable option for developing energy‐efficient and high‐performance polarization‐sensitive detectors.