Regensburg 2010 – scientific programme
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O: Fachverband Oberflächenphysik
O 82: Graphene IV
O 82.5: Talk
Friday, March 26, 2010, 12:15–12:30, H31
Quasi-freestanding Graphene on SiC(0001) — •Florian Speck1, Markus Ostler1, Jonas Röhrl1, Johannes Jobst2, Daniel Waldmann2, Martin Hundhausen1, Lothar Ley1, Heiko B. Weber2, and Thomas Seyller1 — 1Lehrstuhl für Technische Physik, Universität Erlangen-Nürnberg, Germany — 2Lehrstuhl für Angewandte Physik, Universität Erlangen-Nürnberg, Germany
Epitaxial graphene thermally grown on SiC(0001) is a first choice candidate for the development of graphene-based electronics. The graphene layer directly in contact with the substrate is covalently bound and forms the (6√3 × 6√3)R30∘ reconstruction. It lacks the electronic properties of graphene and is thus called buffer layer. Only the next graphene layer, which resides on top of the buffer layer, exhibits the characteristic Dirac cone. Hydrogen can saturate dangling bonds on Si and SiC surfaces and is therefore a promising candidate for a chemical modification of the interface. Riedl et al. demonstrated the conversion of the buffer layer into monolayer graphene by annealing in hydrogen [1]. Here we present a comprehensive spectroscopic study on buffer layer and monolayer graphene samples annealed in hydrogen. Si-H bonds at the interface are detected by infrared absorption spectroscopy, proving the intercalation of hydrogen underneath the buffer layer. The graphene layer formed by this process interacts only weakly with the substrate. Raman spectroscopy indicates the presence of short range defect sites. Hall effect measurements show p-type conduction with hole mobilities up to 1250 cm2 V−1 s−1 at room temperature.
[1] C. Riedl et al., arXiv:0911.1953v1