Novel Optoelectronic Devices: Transition-Metal-Dichalcogenide-Based 2D Heterostructures

Over the past decade, graphene and other 2D materials have attracted much attention in both fundamental studies and potential applications due to their extraordinary properties. In particular, heterostructures based on these van der Waals (vdW) materials have become one of the leading hot topics in the electronic and optoelectronic field. As representative photoactive 2D materials, transition metal dichalcogenides (TMDs) play a critical role in the creation of 2D optoelectronic heterojunctions themselves or in combination with other 2D materials. Here, the optoelectronics of three types of TMD-based 2D heterostructures are reviewed: (1) heterostructures between different TMDs, including vertical vdW heterojunctions fabricated by mechanical transfer and direct synthesis, and lateral in-plane heterostructures formed via epitaxial growth; (2) heterostructures between TMDs and graphene built by stacking, vdW epitaxy, and lateral assembly; (3) heterostructures between TMDs and other novel 2D materials, such as black phosphorus and GaTe. The operation mechanism of all these optoelectronic devices is discussed.