One-Step Epitaxial Growth of Multilayer MoS₂/SnS₂ Vertical Nanosheets for High-Performance Photodetectors

Two-dimensional (2D) van der Waals heterostructures have aroused widespread interest in basic research and device construction because of their unique physical properties and better device performance. Previous studies often focused on vertical bilayer heterostructures composed of two distinct monolayer 2D materials using chemical vapor deposition (CVD) processes. Here, a KI-assisted confined-space CVD method is reported to synthesize multilayer MoS2/SnS2 vertical heterostructure nanosheets composed of monolayer MoS2 and multilayer SnS2. The optical characterizations reveal a clear interface between monolayer MoS2 and multilayer SnS2 as well as the vertical heterostructure. Photodetectors based on the as-grown MoS2/SnS2 heterostructure nanosheets can obtain a maximum responsivity of 9611 A/W under visible light illumination. Meanwhile, the minimum response time is about 510 μs. The ultrasensitive photoresponse may be related to the higher light absorption of such multilayer SnS2. This work not only provides an approach to construct multilayer 2D heterostructure nanosheets but also demonstrates their potential advantages in the application of high-performance photodetectors.