Direct evidence of electronic interaction at the atomic-layer-deposited MoS2 monolayer/SiO2 interface

TL;DR

This study provides direct spectroscopic evidence of electronic interactions at the atomic-layer-deposited MoS2 monolayer/SiO2 interface, revealing the influence of van der Waals forces on the electronic structure.

Contribution

It combines experimental spectroscopy and ab-initio simulations to demonstrate the electronic interaction at the MoS2/SiO2 interface, highlighting the role of van der Waals interactions.

Findings

Spectroscopic features indicate strong MoS2-SiO2 interactions.

Van der Waals forces modify the electronic structure.

Experimental spectra differ from ideal free-standing MoS2.

Abstract

The electronic structure of an atomic-layer-deposited MoS2 monolayer on SiO2 was investigated using X-ray absorption spectroscopy (XAS) and synchrotron X-ray photoelectron spectroscopy (XPS). The angle-dependent evolution of the XAS spectra and the photon-energy-dependent evolution of the XPS spectra were analyzed in detail using an ab-initio electronic structure simulation. Although similar to the theoretical spectra of an ideal free-standing MoS2 ML, the experimental spectra exhibit features that are distinct from those of an ideal ML, which can be interpreted as a consequence of S-O van der Waals (vdW) interactions. The strong consensus among the experimental and theoretical spectra suggests that the vdW interactions between MoS2 and adjacent SiO2 layers can influence the electronic structure of the system, manifesting a substantial electronic interaction at the MoS2-SiO2 interface.