Electronic band structure of Two-Dimensional WS2/Graphene van der Waals Heterostructures

TL;DR

This study investigates the electronic and structural properties of WS2/graphene heterostructures, revealing well-defined band features and strong valence band splitting, with implications for valleytronic device applications.

Contribution

It provides detailed experimental and theoretical analysis of WS2 on graphene, highlighting the electronic properties and band structure relevant for future device development.

Findings

Good electronic properties observed

Valence band splitting of 0.44 eV at K points

Top valence band close to suspended WS2 calculations

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. Here, we report the electronic and structural properties of transferred single layer WS2 on epitaxial graphene using micro-Raman spectroscopy, angle-resolved 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 WS2 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 WS2. . Our results provide an important reference for future studies of electronic properties of WS2 and its applications in valleytronic devices.