Van der Waals Integration of 1D Nb ₂ Pd ₃ Se ₈ and 2D WSe ₂ for Gate‐Tunable In‐Sensor Image Processing

Abstract

Abstract 1D and 2D integrations provide significant promise for machine vision by enabling compact, power‐efficient optoelectronic devices. However, the potential of 1D materials in mixed‐dimensional structures for convolutional image processing remains largely unexplored. Here, high‐quality 1D‐Nb 2 Pd 3 Se 8 is synthesized and integrated with 2D‐WSe 2 to form self‐powered photodetectors, exhibiting gate‐tunable bi‐directional photoresponse for image processing. Utilizing the narrow band gap and favorable work function of 1D‐Nb 2 Pd 3 Se 8 , a type‐I junction and 1D van der Waals interface are established with transition metal dichalcogenides. The gate tunable built‐in electric field enables switching between n‐p and n‐n + configurations, allowing the drift photocurrent direction to be reversed, achieving both negative and positive photocurrent. Furthermore, efficient conversion of high‐energy photons along one dimension enhances sensitivity at 375 nm. The device achieves a responsivity of 232 mA W −1 , external quantum efficiency of 77% at 375 nm illumination, rapid response time of ~3 µs, detectivity of 6.35 × 10 10 Jones, and broadband photodetection from ultraviolet to near‐infrared. The demonstrated gate‐controllable, bi‐directional photoresponse with linear power dependence in a 1D heterojunction offers a promising platform for in‐sensor convolutional processing with high integration and portability.