Surface Functionalization of Quasi-Two-Dimensional MoS2 in Nitrogen and Oxygen Plasma.

The effect of nitrogen and oxygen plasma on quasi-two-dimensional MoS₂ films is studied experimentally and theoretically in order to identify the main mechanisms of surface functionalization and the influence on the structure and on the properties of the films. Diagnostics of samples before and after treatment using radicals and ions is carried out ex situ using Raman spectroscopy, spectroscopic ellipsometry, X‑ray photoelectron spectroscopy, etc. It is shown that the effect of the nitrogen and oxygen plasma on ultrathin MoS₂ films results in modifying the near-surface layers of the samples due to removal of sulfur and incorporation of incident atoms into the resulting vacancies. The simulation of density functional theory is applied to reveal the main mechanisms of surface functionalization in MoS₂ monolayers and to explain the experimental results. [ABSTRACT FROM AUTHOR]