Electronic band structure of two-dimensional WS2/Graphene van der Waals heterostructures

Abstract

Combining single - layer two - dimensional semiconducting transition metal dichalcogenides (TMDs) with graphene layer in van der Waals heterostructures offers an intriguing means of controlling the electronic properties through these heterostructures . Her e , we report the electronic and structural properties of transferred single layer WS 2 on epitaxial graphene using micro - Raman spectroscopy, a ngle - resolv ed photoemission spectroscopy measurements (ARPES) and Density Functional Theory (DFT) calculations . The results show good electronic properties as well as well - defined band arising from the strong splitting of the single layer WS 2 valence band at K points , with a maximum splitting of 0.44 eV. By comparing our DFT results with local and hybrid functionals, we find the top valence band of the experimental heterostructure is close to the calculations for suspended single layer WS 2 . . Our results provide an i mportant reference for future studies of electronic properties of WS 2 and its applications in valleytronic devices.