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.
Ma et al. (Mon,) studied this question.