title: Distinctive in-Plane Cleavage Behaviors of Two-Dimensional Layered Materials.
abstract: Mechanical exfoliation from bulk layered crystal is widely used for preparing two-dimensional (2D) layered materials, which involves not only out-of-plane interlayer cleavage but also in-plane fracture. Through a statistical analysis on the exfoliated 2D flakes, we reveal the in-plane cleavage behaviors of six representative layered materials, including graphene, h-BN, 2H phase MoS2, 1T phase PtS2, FePS3, and black phosphorus. In addition to the well-known interlayer cleavage, these 2D layered materials show a distinctive tendency to fracture along certain in-plane crystallography orientations. With theoretical modeling and analysis, these distinct in-plane cleavage behaviors can be understood as a result of the competition between the release of the elastic energy and the increase of the surface energy during the fracture process. More importantly, these in-plane cleavage behaviors provide a fast and noninvasive method using optical microscopy to identify the lattice direction of mechanical exfoliated 2D layered materials.
authors: Yao
authors: Y
authors: Guo
authors: Chunru
authors: C
authors: Liu
authors: Qifang
authors: Q
authors: Yin
authors: Physics Department, Southern University of Science and Technology , Shenzhen 518055, People's Republic of China.
authors: Chengrong
authors: C
authors: Wei
authors: Shenghuang
authors: S
authors: Lin
authors: Department of Chemical Engineering, Kansas State University , Manhattan, Kansas 66506, United States.
authors: Tim B
authors: TB
authors: Hoffman
authors: Yuda
authors: Y
authors: Zhao
authors: Department of Chemical Engineering, Kansas State University , Manhattan, Kansas 66506, United States.
authors: J H
authors: JH
authors: Edgar
authors: Key Laboratory for the Physics and Chemistry of Nanodevices, Department of Electronics, Peking University , Beijing 100871, People's Republic of China.
authors: Qing
authors: Q
authors: Chen
authors: Shu Ping
authors: SP
authors: Lau
authors: Physics Department, Southern University of Science and Technology , Shenzhen 518055, People's Republic of China.
authors: Junfeng
authors: J
authors: Dai
authors: Haimin
authors: H
authors: Yao
authors: Department of Electrical Engineering, Stanford University , Stanford, California 94305, United States.
authors: H-S Philip
authors: HS
authors: Wong
authors: Yang
authors: Y
authors: Chai
keywords: anisotropy; graphene; in-plane cleavage; transition metal dichalcogenides; two-dimensional layered materials