High-performance nonlinear photodetector based on MoTe2/CdS/ReS2 dual heterojunction for polarization-visible light imaging

Photodetectors with high sensitivity and polarization selectivity are critical for applications ranging from environmental monitoring to advanced imaging. Transition metal dichalcogenides (TMDs) offer remarkable stability, yet their low photocurrent-to-dark current ratio and intrinsic limitations hinder their exploration in polarization-resolved visible light imaging and nonlinear optics. Here, we present a MoTe2/CdS/ReS2 dual heterojunction photodetector exhibiting outstanding performance and nonlinear optical response. The device achieves a responsivity of 492.7 A/W, an on/off current ratio of 4.15 × 106, rapid response times of 172/299 μs, an external quantum efficiency up to 1.04 × 105%, and a detectivity of 3.12 × 1015 Jones. It displays pronounced polarization-dependent photocurrent and enables high-fidelity imaging under varying polarization angles. Second harmonic generation mapping confirms strong second-order nonlinear optical activity arising from inversion symmetry breaking, while photoluminescence mapping reveals efficient interlayer charge separation. Band structure analysis elucidates the mechanisms underpinning the enhanced photoresponse. This work establishes a platform for nonlinear optical polarized imaging and offers a pathway to advance the optoelectronic performance of TMD-based materials.