Grain Boundaries in Graphene on SiC(000(1)over-bar) Substrate

Grain boundaries in epitaxial graphene on the SiC(000 (1) over bar) substrate are studied using scanning tunneling microscopy and spectroscopy. All investigated small-angle grain boundaries show pronounced out-of-plane buckling induced by the strain fields of constituent dislocations. The ensemble of observations determines the critical misorientation angle of buckling transition theta(c) = 19 +/- 2 degrees. Periodic structures are found among the flat large-angle grain boundaries. In particular, the observed theta = 33 +/- 2 degrees highly ordered grain boundary is assigned to the previously proposed lowest formation energy structural motif composed of a continuous chain of edge-sharing alternating pentagons and heptagons. This periodic grain boundary defect is predicted to exhibit strong valley filtering of charge carriers thus promising the practical realization of all-electric valleytronic devices.


Published in:
Nano Letters, 14, 11, 6382-6386
Year:
2014
Publisher:
Washington, Amer Chemical Soc
ISSN:
1530-6984
Keywords:
Laboratories:




 Record created 2015-02-20, last modified 2018-10-07

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