Irradiation with high-energy particles has recently emerged as an effective tool for tailoring the properties of two-dimensional transition metal dichalcogenides. In order to carry out an atomically-precise manipulation of the lattice, a detailed understanding of the beam-induced events occurring at the atomic scale is necessary. Here, we investigate the response of 1T′-MoS2 to the electron irradiation by abinitio molecular dynamics means. Our simulations suggest that an electron beam with energy smaller than 75 keV does not result in any knock-on damage. The displacement threshold energies are different for the two nonequivalent sulfur atoms in 1T′-MoS2 and strongly depend on whether the top or bottom chalcogen layer is considered. As a result, a careful tuning of the beam energy can promote the formation of ordered defects in the sample. We further discuss the effect of the electron irradiation in the neighborhood of a defective site, the mobility of the sulfur vacancies created and their tendency to aggregate. Overall, our work provides useful guidelines for the imaging and the defect engineering of 1T′-MoS2 using electron microscopy.
@article{arxiv.1804.04599,
title = {Single-layer $1T'$-MoS$_2$ under electron irradiation from $ab$ $initio$ molecular dynamics},
author = {Michele Pizzochero and Oleg V. Yazyev},
journal= {arXiv preprint arXiv:1804.04599},
year = {2018}
}