Fast-Response Self-Powered Polarized Broadband Photodetector Based on ReS ₂ /Nb ₃ Cl ₈ van der Waals Heterostructure

Two-dimensional van der Waals heterojunctions have attracted considerable attention in photodetector research owing to their excellent material compatibility and superior optoelectronic performance. Heterojunctions constructed from 2D materials, with their nanoscale thickness and intrinsic van der Waals interfacial contact characteristics, exhibit unique photoresponse behaviors. In this work, we successfully fabricate a self-powered photodetector based on a ReS 2 /Nb 3 Cl 8 vdWH. The device demonstrates a low dark current (∼10 –13 A) and achieves a rectification ratio of 1.2 × 10 3 under zero bias. Owing to the built-in electric field at the heterojunction interface, the device manifests photovoltaic characteristics, yielding an open-circuit voltage of 0.078 V and a short-circuit current of 0.18 nA. This detector achieves a high responsivity of 69.5 mA/W, an excellent specific detectivity of 1.67 × 10 12 Jones, a switching ratio of 2.58 × 10 3, an anisotropy ratio of up to 1.85, and a fast response time of 88/102 μs at zero bias voltage. Furthermore, the device exhibits outstanding self-powered photoresponse characteristics across a broad spectral range from 365 to 940 nm. These results effectively demonstrate the significant application value of the ReS 2 /Nb 3 Cl 8 vdWH for broadband self-powered photodetection.