Interlayer Transition Induced Infrared Response in WSe₂/WS₂ Van Der Waals Heterostructure Photodetectors with Polarization and Self‐Powered Effects

Abstract Van der Waals (vdWs) heterojunction photodetectors based on 2D transition metal dichalcogenides are widely utilized in optoelectronic detection, where the band structure of the heterojunction plays a crucial role in determining the performance of the photodetector. In this study, a WSe₂/WS₂ vdWs heterostructure photodetector with a type‐II band alignment is fabricated. Benefiting from the efficient separation of photogenerated carriers under the type‐II band alignment, the device exhibits remarkable self‐powered characteristics, achieving a responsivity of 0.32 A/W and a quantum efficiency of 76% at zero bias under 532 nm laser illumination, with a specific detectivity of 6.15 × 10¹³ Jones. Notably, due to the interlayer transitions of photogenerated carriers, the operating wavelength range of the detector is extended to the telecommunication band (i.e., 1550 nm). Furthermore, the device exhibits a significant ability to detect polarized light, achieving a photocurrent anisotropy ratio of 16 under a 532 nm laser line. This work provides a straightforward approach to realizing a photodetector that integrates self‐powered, broadband, and polarization‐sensitive detection functionalities.