Computer study of the structure and thermal stability of a monolayer mos2 film on a diamond substrate

Abstract

MoS2 is a promising candidate for next-generation electrical and optoelectronic devices. The use of chemical vapor deposition allows obtaining high-quality MoS2 monolayers on a diamond substrate. However, it is not clear how firmly the MoS2 monolayer is held on the diamond substrate at a high temperature and how the structure of the MoS2 monolayer changes after its deposition on the diamond substrate and subsequent heating on it. In this paper, the molecular dynamics method is used to study the stability of single-layer MoS2 in the temperature range of 250 – 550 K. The molybdenum disulfide film on a diamond substrate structure is studied by constructing Voronoi polyhedra. Polyhedra were built around Mo atoms, and faces are formed by neighboring S atoms. The distributions of polyhedrons by the number of faces were found. These distributions were also calculated for truncated polyhedra obtained by eliminating small geometric elements. A comparison of the obtained statistical distributions for a MoS2 monolayer on a diamond substrate with the corresponding characteristics of an autonomous monolayer MoS2 indicates a significant change in the structure of the monolayer. This change is a result of its deposition on the diamond substrate. When the temperature reaches 550 K, the MoS2 film is completely separated from the substrate. There is a singularity near this temperature, which indicates the thermal instability of the system under investigation. © 2019, Institute for Metals Superplasticity Problems of Russian Academy of Sciences. All rights reserved.