title: The influence of edge structure on the electronic properties of graphene quantum dots and nanoribbons.
abstract: Graphene shows promise as a future material for nanoelectronics owing to its compatibility with industry-standard lithographic processing, electron mobilities up to 150 times greater than Si and a thermal conductivity twice that of diamond. The electronic structure of graphene nanoribbons (GNRs) and quantum dots (GQDs) has been predicted to depend sensitively on the crystallographic orientation of their edges; however, the influence of edge structure has not been verified experimentally. Here, we use tunnelling spectroscopy to show that the electronic structure of GNRs and GQDs with 2-20 nm lateral dimensions varies on the basis of the graphene edge lattice symmetry. Predominantly zigzag-edge GQDs with 7-8 nm average dimensions are metallic owing to the presence of zigzag edge states. GNRs with a higher fraction of zigzag edges exhibit a smaller energy gap than a predominantly armchair-edge ribbon of similar width, and the magnitudes of the measured GNR energy gaps agree with recent theoretical calculations.
authors.affiliation: Beckman Institute for Advanced Science and Technology, University of Illinois, 405 North Mathews Avenue, Urbana, Illinois 61801-2325, USA. ritter@engineering.uiuc.edu
authors.forename: Kyle A
authors.initials: KA
authors.lastname: Ritter
authors.forename: Joseph W
authors.initials: JW
authors.lastname: Lyding