Berlin 2015 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 117: Graphene: Intercalation (jointly with O, HL)
TT 117.7: Vortrag
Freitag, 20. März 2015, 12:00–12:15, MA 041
Approaching ideal graphene: The structure of hydrogen- and germanium-intercalated graphene on 6H-SiC(0001) — •F.C. Bocquet1,2, J. Sforzini1,2, T. Denig3, A. Stöhr3, T.-L. Lee4, S. Subach1,2, U. Starke3, and F.S. Tautz1,2 — 1Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich, 52425 Jülich, Germany — 2Jülich Aachen Research Alliance (JARA), Fundamentals of Future Information Technology, 52425 Jülich, Germany — 3Max Planck Institute for Solid State Research, Heisenbergstraße, 70569 Stuttgart, Germany — 4Diamond Light Source Ltd, Didcot, OX11ODE, Oxfordshire, United Kingdom
We investigated Quasi-Free-standing Monolayer Graphene epitaxially grown on 6H-SiC(0001) obtained by decoupling the buffer-layer from the Si-terminated surface by hydrogen intercalation (1) or by intercalating one or two monolayers of germanium (2). All three samples show a clear linear dispersion around the K-point, confirming their Quasi-Free-standing character. We used the X-ray standing wave (XSW) technique, combining dynamical diffraction and X-ray photoelectron spectroscopy, to detect the coherent distribution of the chemically different species (Si, C and Ge) at the interface. Based on the lattice parameter of bulk SiC, we accurately determine the vertical height differences between each chemical species. Comparing the overlaps of van der Waals radii between the graphene layer and the topmost intercalating atoms, we conclude on the degree of decoupling of the graphene layers.