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arXiv · 1502.07791

Real-time observation of epitaxial graphene domain reorientation

Paul C. Rogge·Konrad Thürmer·Michael E. Foster·Kevin F. McCarty·Oscar D. Dubon·Norman C. Bartelt
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Abstract

Graphene films grown by vapor deposition tend to be polycrystalline due to the nucleation and growth of islands with different in-plane orientations. Here, using low-energy electron microscopy, we find that micron-sized graphene islands on Ir(111) rotate to a preferred orientation during thermal annealing. We observe three alignment mechanisms: the simultaneous growth of aligned domains and dissolution of rotated domains, i.e., "ripening"; domain-boundary motion within islands; and continuous lattice-rotation of entire domains. By measuring the relative growth velocity of domains during ripening, we estimate that the driving force for alignment is on the order of 0.1 meV per C atom and increases with rotation angle. A simple model of the orientation-dependent energy associated with the moiré corrugation of the graphene sheet due to local variations in the graphene-substrate interaction reproduces the results. This work suggests new strategies for improving the van der Waals epitaxy of 2D materials.

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Paul C. Rogge, Konrad Thürmer, Michael E. Foster, Kevin F. McCarty, Oscar D. Dubon, Norman C. Bartelt. 2015-02-26. Real-time observation of epitaxial graphene domain reorientation. https://doi.org/10.1038/ncomms7880

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