Direct Evidence of Electronic Interaction at the Atomic-Layer-Deposited MoS2 Monolayer/SiO2 Interface

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.

Keywords: MoS2; SiO2; X-ray absorption spectroscopy; electronic structure; interface; synchrotron X-ray photoelectron spectroscopy; van der Waals interaction.