Preparation and optoelectronic performance of two-dimensional MoSe2/WSe2 lateral and vertical heterostructures

Two-dimensional materials Transition Metal Dichalcogenides (TMDs) are a novel type of semiconductor material with tunable bandgap and atomic-level thickness. Different TMDs can be flexibly combined to form heterostructures with distinct properties. In this paper, we have prepared two-dimensional MoSe2/WSe2 vertical and lateral heterostructures by using CVD and a combination of PVD and CVD, respectively. Subsequently, the structure, electronic and optoelectronic properties of these two types of heterostructures were characterized. The results indicate that field-effect transistors based on single-layer MoSe2/WSe2 lateral heterostructures, and single-layer WSe2/multi-layer MoSe2 and single-layer MoSe2/multi-layer WSe2 vertical heterostructures exhibit significant rectification effects. The in-plane monolayer MoSe2/WSe2 heterostructure devices exhibit the on/ff ratio of up to 104, and the monolayer-multilayer vertical heterostructure reaching 106, significantly outperforming most known devices of the same type. Moreover, the optical response of both in-plane and vertical heterostructures field-effect transistors reach 10 ms. Our research findings offer pathways for the flexible selective growth of in-plane and vertical heterostructures based on TMDs, and provide insights into achieving diverse performance in logic devices.