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

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.