Regensburg 2010 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 52: Graphene II
O 52.5: Vortrag
Mittwoch, 24. März 2010, 16:00–16:15, H31
Quasi-free Standing Epitaxial Graphene on SiC by Hydrogen Intercalation — •Camilla Coletti1, Christian Riedl1, Takayuki Iwasaki1, Alexei A. Zakharov2, and Ulrich Starke1 — 1Max-Planck-Institut für Festkörperforschung, Heisenbergstr. 1, D-70569 Stuttgart, Germany — 2MAX-Lab, Lund University, Box 118, Lund, S-22100, Sweden
Epitaxial graphene grown on silicon carbide (SiC) is an appealing material for future electronic applications. It combines most of the exciting properties of free standing graphene to a manufacturing friendly planar structure. Most of the remaining skepticism towards this material is related to the the strong interaction with the SiC substrate. The SiC surface is covalently bound to the first carbon layer, which act as a buffer-layer and therefore fails in displaying graphene properties. The undesired effects originating from this strong coupling, such as intrinsic n-type doping and degraded transport properties, affect the overlying graphene layers. Annealing the samples in molecular hydrogen offers an elegant solution to the problem of graphene-SiC coupling. ARPES, CLPES and LEEM demonstrate that hydrogen atoms migrate through the graphene layers, intercalate between the SiC substrate and the buffer-layer and bind to the Si atoms of the SiC(0001) surface. Thus the buffer-layer, decoupled from the SiC substrate, is turned into a quasi-free standing graphene monolayer. Similarly, epitaxial monolayer graphene turns into a decoupled bilayer. The intercalation process represents a highly promising route towards epitaxial graphene based nanoelectronics.