Dresden 2011 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

O: Fachverband Oberflächenphysik

O 29: Graphene I

O 29.1: Vortrag

Dienstag, 15. März 2011, 11:15–11:30, WIL B321

Graphene Growth Kinetics on Ru(0001) as Function of the Termination of Graphene Islands — •Sebastian Daenhardt¹, Sebastian Guenther², Stefan Schmitt³, and Joost Wintterlin¹ — ¹Department Chemie, LMU Muenchen — ²Fachgebiet Phys. Chemie (Katalyse) , TU Muenchen — ³SPECS GmbH, Voltastr. 5, 13355 Berlin

For a deeper understanding of the growth kinetics of graphene on metal surfaces it is important to monitor the growth of the islands in situ, at the high temperatures of the CVD process. Here we present the results of an in situ STM investigation of the growth of graphene on Ru(0001) during ethylene decomposition between 650 and 750^∘C. We have also monitored the removal of the graphene layer by oxidation in situ. We find that the graphene islands are all zig-zag terminated, but that there are still two different island terminations, which are rotated by an angle of 120^∘, that display different growth velocities. The two terminations also differ with respect to the binding to Ru steps. The slowly growing edges tend to bind to Ru steps during the growth, in contrast to the faster growing edges. The slowly growing edges can also etch into ascending steps, so that the graphene islands can grow on given terraces without crossing the steps. In all of these cases graphene grows in a "quantized" form, i.e., by addition of full unit cells of the moiré structure. The data demonstrate a massive restructuring of the Ru surface under the growth conditions, and they provide insight into the energetics of the graphene-Ru edges.