Critical thickness for interface misfit dislocation formation in two-dimensional materials

Brian C. McGuigan, Pascal Pochet, and Harley T. Johnson
Phys. Rev. B 93, 214103 – Published 6 June 2016

Abstract

In-plane heterostructures of two-dimensional (2D) materials form interface misfit dislocations to relieve lattice mismatch strain, much like heterostructures of 3D materials. Here, using graphene-hexagonal boron nitride (h-BN) as a model system, we consider interface misfit dislocations in 2D lateral heterostructures resting on a flat support layer that prevents out-of-plane deformation. Using an accurate empirical interatomic potential, we carry out a rigorous energetic analysis of the graphene/h-BN interface with 5-7 or 8-6 dislocation cores. We define and extract critical thicknesses for the formation of an interface misfit dislocation in the heterostructure, for the limiting cases when the h-BN or graphene domains are significantly different in size (equivalent to the classic 3D thin film critical thickness problem), and the intermediate case, where the h-BN and graphene domains are of comparable size (equivalent to the classic 3D compliant substrate problem). This makes it possible to compare the alternative dislocation core structures and to determine the resulting dislocation core energy in a continuum analysis. It also reveals a design space where defect-free heterostructures can be grown.

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  • Received 14 February 2016
  • Revised 12 May 2016

DOI:https://doi.org/10.1103/PhysRevB.93.214103

©2016 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

Brian C. McGuigan1, Pascal Pochet2,3,*, and Harley T. Johnson1,2,†

  • 1Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
  • 2Université Grenoble-Alpes, Grenoble 38000, France
  • 3Atomistic Simulation Laboratory (L_Sim), CEA, INAC F-38054, Grenoble 38000, France

  • *pascal.pochet@cea.fr
  • htj@ilinois.edu

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Issue

Vol. 93, Iss. 21 — 1 June 2016

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