Polarimetric Photodetector with Ultrahigh‐Sensitivity and Polarity Reverse Based on Quasi‐1D Semimetal (TaSe 4 ) 2 I/2D MoTe 2 Heterojunction

Abstract Polarimetric photodetectors, capable of resolving both intensity and polarization states of light, are pivotal for advanced multispectral imaging and target recognition. Examples have been demonstrated for applications such as autonomous vehicle lidar systems and polarization‐based biomedical imaging, where accurate polarization information improves target detection and contrast. However, conventional polarimetric detectors are constrained by complicated optical components and single‐band polarization resolution. Here, a mixed‐dimensional heterojunction strategy is proposed that synergizes the unique optoelectronic properties and giant anisotropy of quasi‐1D Weyl semimetal with 2D semiconductor 2H‐MoTe 2 , achieving great dark current suppression and dual‐band polarization‐spectrum detection through interfacial band engineering. The (TaSe 4 ) 2 I/2H‐MoTe 2 photodetectors demonstrate high‐performance broadband operation (395–2200 nm) with a detectivity of 2.1×10 12 Jones, responsivity of 40 A W −1 , and quantum efficiency exceeding 11400%, setting a new benchmark for comprehensive performance in phototransistors. Notably, the intrinsic wavelength‐dependent dichroic inversion of (TaSe 4 ) 2 I enables the orthogonal polarization response polarity reversal between the visible (532 nm) and infrared (1550 nm) bands. Note that dual‐band polarization imaging is successfully achieved, which can be used for multispectral interference identification. This work demonstrates a feasible strategy by constructing mixed‐dimensional semimetal/semiconductor heterojunctions toward future ultrahigh‐sensitivity and broadband polarimetric detectors.