Elastic Properties of Chemical-Vapor-Deposited Monolayer MoS2, WS2, and Their Bilayer Heterostructures

TL;DR

This study measures the elastic properties of CVD-grown monolayer MoS2 and WS2, revealing their high 2D elastic moduli and insights into interlayer interactions in heterostructures, which are crucial for flexible device applications.

Contribution

It provides the first comprehensive characterization of the elastic properties of CVD monolayer MoS2 and WS2 and their heterostructures, highlighting their similarity to exfoliated layers and implications for material engineering.

Findings

High 2D elastic moduli (~170 N/m) for CVD monolayer MoS2 and WS2

Heterostructure moduli are lower than sum of individual layers but similar to bilayer homostructures

Insights into interlayer interactions in 2D van der Waals structures

Abstract

Elastic properties of materials are an important factor in their integration in applications. Chemical vapor deposited (CVD) monolayer semiconductors are proposed as key components in industrial-scale flexible devices and building blocks of 2D van der Waals heterostructures. However, their mechanical and elastic properties have not been fully characterized. Here we report high 2D elastic moduli of CVD monolayer MoS2 and WS2 (~ 170 N/m), which is very close to the value of exfoliated MoS2 monolayers and almost half the value of the strongest material, graphene. The 2D moduli of their bilayer heterostructures are lower than the sum of 2D modulus of each layer, but comparable to the corresponding bilayer homostructure, implying similar interactions between the hetero monolayers as between homo monolayers. These results not only provide deep insight to understanding interlayer interactions in 2D van der Waals structures, but also potentially allow engineering of their elastic properties as desired.