Mechanical exfoliation of two-dimensional materials

Enlai Gao, Shao Zhen Lin, Zhao Qin, Markus J. Buehler, Xi Qiao Feng, Zhiping Xu

Research output: Contribution to journalArticle

21 Scopus citations

Abstract

Two-dimensional materials such as graphene and transition metal dichalcogenides have been identified and drawn much attention over the last few years for their unique structural and electronic properties. However, their rise begins only after these materials are successfully isolated from their layered assemblies or adhesive substrates into individual monolayers. Mechanical exfoliation and transfer are the most successful techniques to obtain high-quality single- or few-layer nanocrystals from their native multi-layer structures or their substrate for growth, which involves interfacial peeling and intralayer tearing processes that are controlled by material properties, geometry and the kinetics of exfoliation. This procedure is rationalized in this work through theoretical analysis and atomistic simulations. We propose a criterion to assess the feasibility for the exfoliation of two-dimensional sheets from an adhesive substrate without fracturing itself, and explore the effects of material and interface properties, as well as the geometrical, kinetic factors on the peeling behaviors and the torn morphology. This multi-scale approach elucidates the microscopic mechanism of the mechanical processes, offering predictive models and tools for the design of experimental procedures to obtain single- or few-layer two-dimensional materials and structures.

Original languageEnglish (US)
Pages (from-to)248-262
Number of pages15
JournalJournal of the Mechanics and Physics of Solids
Volume115
DOIs
StatePublished - Jun 2018

Keywords

  • Atomistic simulations
  • Mechanical exfoliation
  • Peeling
  • Tearing
  • Two-dimensional materials

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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