Hybrid‐Dimensional Polycrystalline van der Waals Heterostructure for High Responsivity and Broadband Detection

Abstract 2D‐based photothermoelectric (PTE) photodetectors have emerged as promising candidates for high‐performance broadband detection, owing to their outstanding optoelectronic and thermal characteristics. However, the intrinsically poor light absorption and high thermal conductivity of 2D materials result in limited responsivity and sensitivity. The 2D/3D hybrid‐dimensional heterostructure, featuring a lattice‐mismatch‐free interface, successfully integrates the superior electrical properties of 2D materials with the high light absorption and excellent sensitivity of 3D materials, providing a novel platform for developing high‐performance optoelectronic devices. In this work, a 2D SnSe 2 /3D PbSe hybrid‐dimensional van der Waals (vdWs) heterojunction is proposed, leveraging its distinct band alignment and efficient thermal management to effectively suppress the potential barrier while achieving enhanced PTE response, ultimately enabling a high‐speed, broadband (500–4100 nm) photodetector. Specifically, the device demonstrates a high responsivity of 2343 V/W, an ultrafast response speed ≈60 µs, and an exceptional detectivity of ≈10 10 Jones under 780 nm illumination. Notably, it maintains a responsivity exceeding 60 V/W and a rapid response time of 54 µs even at 3500 nm. In summary, this study exploits a hybrid‐dimensional polycrystalline vdWs heterostructure to introduce a novel strategy for designing high‐performance, broadband photodetectors.