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O: Fachverband Oberflächenphysik

O 60: Poster Session IV (Solid/liquid interfaces; Semiconductors; Oxides and insulators; Graphene; Plasmonics and nanooptics; Electronic Structure; Surface chemical reactions; Heterogeneous catalysis)

O 60.41: Poster

Mittwoch, 16. März 2011, 17:30–21:00, P4

Growth of uniaxial graphene nanostructures by self-assembly — •Jens Baringhaus, Thomas Langer, Herbert Pfnür, and Christoph Tegenkamp — Institut für Festkörperphysik, Leibniz Universität Hannover, Appelstrasse 2, 30167 Hannover, Germany

Graphene nanostructures such as ribbons and dots are building blocks for any graphene based device architecture. Furthermore, the controlled fabrication of nanostructures allows to study the feedback of defects towards the peculiar transport properties seen in perfect 2d templates. Among others the epitaxial growth of graphene on pre-patterned SiC is a promising strategy for growing such nanostructures on insulating substrates.
Using vicinal 4H-SiC(0001) substrates (4^∘ miscut) the in-situ graphitization process has been monitored by spot profile analysis LEED and angle resolved electron energy loss spectroscopy (ELS). At first for temperatures above 1200^∘ step bunching sets in. The flat terrace sites are in the order of 20 nm, thus, the initial structural anisotropy in not reflected in the plasmon dispersion of graphene. In a second approach uniaxial mesa structures of 6H-SiC(0001) (1 µ m in width) were fabricated by means of photolithography and reactive ion etching (RIE). Heating of the substrate induces step flow and the development of inclined nano-facets. At high temperatures silicon desorbs predominantly from these nano-facets leading to the formation of graphene ribbons. The structure and plasmon properties are analyzed by SEM, STM and EELS. In addition, also first transport properties will be presented.