title: Growth mechanism of hexagonal-shape graphene flakes with zigzag edges.
abstract: The properties of a graphene nanostructure are strongly influenced by the arrangement of the atoms on its edge. Growing graphene nanostructures with specified edge types in practical, scalable ways has proven challenging, with limited success to date. Here we report a method for producing graphene flakes with hexagonal shape over large areas, by a brief chemical vapor deposition growth at atmospheric pressure on polished Cu catalyst foil, with limited carbon feedstock. Raman spectra show evidence that the edges of the hexagonal crystallites are predominantly oriented along the zigzag direction. Density functional theory calculations demonstrate that the edge selectivity derives from favorable kinetics of sequential incorporation of carbon atoms to the vacancies in nonzigzag portions of the edges, driving the edges to pure zigzag geometry. This work represents an important step toward realization of graphene electronics with controlled edge geometries, which might find use in digital logic applications or zigzag-edge-based spintronic devices.
authors: Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6396, USA.
authors: Zhengtang
authors: Z
authors: Luo
authors: Seungchul
authors: S
authors: Kim
authors: Nicole
authors: N
authors: Kawamoto
authors: Andrew M
authors: AM
authors: Rappe
authors: A T Charlie
authors: AT
authors: Johnson