title: Elastic properties of chemical-vapor-deposited monolayer MoS2, WS2, and their bilayer heterostructures.
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 two-dimensional (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 into understanding interlayer interactions in 2D van der Waals structures but also potentially allow engineering of their elastic properties as desired.
authors.affiliation: Department of Materials Science and Engineering, University of California , Berkeley, California 94720, United States.
authors.forename: Kai
authors.initials: K
authors.lastname: Liu
authors.forename: Qimin
authors.initials: Q
authors.lastname: Yan
authors.forename: Michelle
authors.initials: M
authors.lastname: Chen
authors.forename: Wen
authors.initials: W
authors.lastname: Fan
authors.forename: Yinghui
authors.initials: Y
authors.lastname: Sun
authors.forename: Joonki
authors.initials: J
authors.lastname: Suh
authors.forename: Deyi
authors.initials: D
authors.lastname: Fu
authors.forename: Sangwook
authors.initials: S
authors.lastname: Lee
authors.forename: Jian
authors.initials: J
authors.lastname: Zhou
authors.forename: Sefaattin
authors.initials: S
authors.lastname: Tongay
authors.forename: Jie
authors.initials: J
authors.lastname: Ji
authors.forename: Jeffrey B
authors.initials: JB
authors.lastname: Neaton
authors.forename: Junqiao
authors.initials: J
authors.lastname: Wu
keywords: Molybdenum disulfide; elastic modulus; heterostructures; monolayer; tungsten disulfide