Dresden 2017 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 86: Graphene: Electronic Properties, Structure and Substrate Interaction I
O 86.7: Vortrag
Donnerstag, 23. März 2017, 12:00–12:15, WIL A317
Surface-assisted self-assembly of graphene nanoribbons — •Axel Enders1,2, Paulo Costa2, Jacob Teeter2, Daniel Miller3, Eva Zurek3, and Alexander Sinitskii2 — 1Experimentalphysik Va, Universität Bayreuth — 2University of Nebraska, Lincoln NE 68588, USA — 3State University of New York at Buffalo, Buffalo 14260, USA
The physical properties of graphene are sensitive to the presence of structural defects, dopants and edges. This creates opportunities to design an electronic bandgap in graphene, which is most consequently exploited in graphene nanoribbons (GNRs), which have edges that are amenable to structural and chemical modification. It is shown that surface-assisted self-assembly is a powerful strategy to build GNRs from the bottom up. As in solution-based self-assembly, also on surfaces the edge structure and chemistry of GNRs is determined by the precursor molecules. But on surfaces the substrate itself can be a control parameter during growth, as can be the method of deposition. Specifically here the self-assembly of 6,11-dibromo-1,2,3,4-tetraphenyltriphenylene and related, appropriately modified precursor molecules was studied on Au(111) and on Cu(111) surfaces. The precursors were deposited under ultrahigh vacuum by two different methods for comparison, which are thermal evaporation and nanoimprinting. Among the significant findings of these studies are the substrate-dependent epitaxial alignment of the ribbons, considerably lower dehalogenation temperatures on Cu(111), and entirely different GNR architectures that can emerge from the same precursors under different conditions.