Self‐Powered, Broadband, and Polarization‐Sensitive Photodetector with Nb‐WS2/Ta2NiSe5 Van der Waals Heterostructure

Abstract Photodetectors play a crucial role in various applications, including communication, imaging, environmental monitoring, and security surveillance. However, developing photodetectors that can simultaneously achieve high sensitivity, high responsivity, low power consumption, polarization sensitivity, and broadband detection remains a significant challenge. In this investigation, the anisotropic properties of Ta₂NiSe₅ are utilized for mid‐infrared polarization‐sensitive photodetection and select suitable 2D materials to enhance device performance. Nb‐WS₂/Ta₂NiSe₅ Van der Waals heterojunction photodetector with low power consumption and broadband response, covering the wavelength range from 405 nm to 3.5 µm, based on the built‐in field. Additionally, the device shows excellent performance at 660 nm, with a responsivity of 57.64 A W −1 , an external quantum efficiency (EQE) of 10 854%, rapid response (118 µs), and recovery times (13 µs). Furthermore, the Nb‐WS₂/Ta₂NiSe₅ structure modulates charge distribution at the interface, enhancing polarization sensitivity and the polarization ratio of 2.2 at 3.5 µm. This work provides a novel strategy for the development of multifunctional, high‐performance photodetectors and opens new avenues for the design and application of next‐generation advanced photodetection devices.