AVS 62nd International Symposium & Exhibition
    2D Materials Focus Topic Thursday Sessions
       Session 2D+EM+MG+NS+SS+TF-ThA

Paper 2D+EM+MG+NS+SS+TF-ThA9
Compliant Substrate Epitaxy: Au on MoS2

Thursday, October 22, 2015, 5:00 pm, Room 212C

Session: Heterostructures of 2D Materials
Presenter: Yuzhi Zhou, UC Berkeley
Authors: Y. Zhou, UC Berkeley
C. Daryl, UC Berkeley
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The heteroepitaxial growth of Au on MoS2, a layered van der Waals bonded dichalcongenide, is analyzed. It is argued that the weak coupling between the layers in the dichalcogenides enables the first substrate layer to deform elastically almost independently from the substrate layers below, and hence enables epitaxial growth for a larger mismatch than might otherwise be expected. Linear, continuum elasticity theory and density functional theory are used to show that a {111} oriented Au film is the preferred over an {001} oriented Au film, despite the fact that the {111} orientation leads to a much higher elastic strain. During the initial stages of growth, the {111} orientation is favored over the {001} orientation due to its lower surface and interfacial energies. As the Au film grows thicker, the elastic relaxation of the first layer of the substrate leads to a reduction in the elastic energy of the growing film. This reduces the elastic energy difference between the {001} and {111} orientations enabling the {111} orientation to remain stable for all film thicknesses. This work is supported by the Director, Office of Science, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.