High-performance broadband photodetectors based on MnSe/SnS 2 heterojunction

Two-dimensional (2D) materials have emerged as promising candidates for broadband photodetectors due to their unique optoelectronic properties. However, intrinsic defects and limited spectral response hinder their practical applications. In this study, we developed a novel 2D heterojunction photodetector by combining non-layered p-type MnSe nanosheets with layered n-type SnS 2 flakes. The MnSe nanosheets were synthesized using chemical vapor deposition, while the SnS 2 flakes were obtained through mechanical exfoliation. The fabricated MnSe/SnS 2 heterojunction device exhibited rectifying behavior with an impressive on/off current ratio over 5000. Remarkably, the photodetector demonstrated a broad spectral response ranging from ultraviolet to near-infrared (405–1060 nm), achieving an exceptionally high responsivity of 10 A W −1 , a detectivity of 3.06 × 10 10 Jones, and an external quantum efficiency of 3068%. The enhanced performance was attributed to the type-II band alignment and built-in potential of the heterojunction, which facilitated effective separation of photogenerated carriers. Furthermore, the device exhibited significant photovoltaic characteristics, enabling self-powered imaging in visible range. This study highlights the potential of 2D non-layered materials in combination with traditional 2D layered materials for the development of high-performance, broadband photodetectors with improved efficiency and self-powered capabilities.