Interface Engineering of van der Waals Devices Based on Metal Disulfide Vertical Heterostructures for Enhanced Photoresponse.

Two-dimensional (2D)-layered semiconductors with atomic thickness, high mobility, and strong light-matter interaction are considered to be promising candidates for the next generation of optoelectronic technology. The high responsivity of photoelectric devices requires efficient transmission and collection of the carriers. However, due to the weakly coupled material interface and the Fermi-level pinning effects at the metal-2D semiconductor interface, the carriers cannot be effectively generated and collected. Here, WS2/SnS2 vertical heterostructures are fabricated by chemical vapor deposition, and the van der Waals devices are constructed. The electron barrier of the transferred Au-2D material interface is about 59 meV, leading to 3 orders of magnitude higher current compared with the device fabricated by the traditional strategy that includes lithography and metal evaporation. The responsivity of the photodetector based on the WS2/SnS2 heterostructure is about 98.33 A/W. This work may inspire the development of high-performance photodetectors based on the 2D heterostructure by interface engineering.