Grain boundaries in graphene on SiC(0001Ì
) substrate.
Nano Lett
; 14(11): 6382-6, 2014 Nov 12.
Article
em En
| MEDLINE
| ID: mdl-25330353
ABSTRACT
Grain boundaries in epitaxial graphene on the SiC(0001Ì
) 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 θc = 19 ± 2°. Periodic structures are found among the flat large-angle grain boundaries. In particular, the observed θ = 33 ± 2° 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.
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MEDLINE
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En
Ano de publicação:
2014
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Article