Gate‐Tunable Photovoltaic Behavior and Polarized Image Sensor Based on All‐2D TaIrTe 4 /MoS 2 Van Der Waals Schottky Diode

2D Weyl semimetal shows potential applications in photodetection, polarization-sensitive imaging, and Schottky barrier diodes, due to its unique band structure and topological nature. However, its inherently large dark current hinders further improvements of the Weyl semimetal-based photodetector's performance. Herein, a Td-TaIrTe4/n-type MoS2 van der Waals (vdWs) heterojunction photodetector is reported. Owing to the effective lateral build-in electric field of 145.3 meV, the Schottky diode shows a high rectification ratio of 6 × 103. Benefiting from the photovoltaic effect, a maximum responsivity (R) of 750 mA W−1 and an Ion/Ioff ratio of 104 under 635 nm illumination are achieved. What's more, the photovoltaic R can be enhanced to 890 mA W−1 at the Vg of 40 V. Because of the highly anisotropic crystalline structure of TaIrTe4 component, a high self-powered photocurrent anisotropic ratio up to 4.19 is realized under 635 nm light at Vg = 40 V. Under self-powered mode, a high-resolution letter of “T” within 150 × 120 pixels can be displayed when the polarization direction is parallel to the armchair direction, while it becomes weak along the zigzag direction. This work provides a valuable route to fabricate anisotropic Weyl semimetal/semiconductor vdWs junction for highly integrated optoelectronics.