Electronic structure of the interface between Au and WSe2

TL;DR

This study explores the electronic interactions at the Au/WSe2 interface, revealing a mixture of van der Waals and covalent-like bonding, with implications for electronic device applications.

Contribution

It provides the first detailed layer-dependent electronic structure analysis of WSe2 on gold, contrasting disordered and ordered gold surfaces with ab initio predictions.

Findings

Strong hybridization at the Brillouin zone centre indicating covalent admixture.

Band shifts suggest charge redistribution at the interface.

Core-level spectroscopy shows a uniform chemical environment for the first WSe2 layer.

Abstract

Understanding the interface between metals and two-dimensional materials is critical for their application in electronics and for the development of metal-mediated exfoliation of large area monolayers. Studying the intricate interactions at the interface requires model systems that enable control of the roughness, purity, and crystallinity of the metal surface. Here, we investigate the layer-dependent electronic structure of WSe_2 on template-stripped gold substrates fabricated using both silicon and mica templates, giving crystallographically disordered and Au(111) ordered surfaces, respectively, and contrast these findings with ab initio predictions. We observe strong hybridization around the Brillouin zone centre at $\overline{\Gamma}$, indicating a covalent admixture in the gold-\WSe~interaction, and band shifts that suggest charge rearrangement at the Au(111) / WSe_2 interface. Core-level spectroscopy shows a single chemical environment for the interfacial WSe_2 layer on the template-stripped gold, distinct from the subsequent layers. These results reveal a mixture of van der Waals and covalent interactions, best described as a covalent-like quasi-bonding with intermediate interaction strength.