Visualization of Strain-Engineered Nanopattern in Center-Confined Mesoscopic WS₂ Monolayer Flakes

Abstract

Strain engineering plays a crucial role in controlling the physical properties of two-dimensional (2D) materials. However, the mechanical behavior of stressed 2D crystals has not been fully understood. In this study, the fracture behavior and accompanying properties of a strained single-crystal monolayer WS 2 of submicron scale were investigated using a theoretical−experimental joint study. After thermal strain, the WS 2 monolayer was split into different forms by several cracks, with the cause of the crack formation being studied using finite element analysis (FEA). The cracks were initiated from the vertex of the nucleation center, extending along the stronger von Mises stress isolines and terminating at the edges of the monolayers. Within the separate sections, ripple regions were observed, forming several typical nanopatterns. The band gap, frictional, viscosity, and elasticity characteristics of the different strain regions were also investigated. The nanopattern should enable flexibility in the design of more sophisticated devices based on 2D materials.

Advanced atomic force microscopies and their applications in two-dimensional materials: a review

“…(a) Tensile strain is achieved when the substrate TEC is less than that of the 2D material, (b) relaxed samples are achieved when the TEC of the substrate and 2D material match, and (c) compressive strain is achieved when the substrate TEC is greater than that of the 2D material. Reprinted with permission from [154]. Copyright (2022) American Chemical Society.…”

Tailoring gas sensing properties of WS2 monolayer via Nb and Co embedding for highly sensitive and selective detection of HCN and H2S gases: a first principle study

“…Due to their large surface-to-volume ratio, high thermal stability, and seamless compatibility with device integration, several experimental studies have investigated the ability of 2D materials for gas sensing [13,14]. Among these materials, the WS 2 monolayer [15] has exhibited remarkable characteristics, such as high mobility, superior chemical durability, and excellent electrical performance [16]. Furthermore, in a recent advance, Ding et al have introduced a highly efficient and clean method for synthesizing 1T-WS 2 , by utilizing a hydrothermal process under a high magnetic field, they have achieved outstanding ambient stability [17].…”