Dresden 2011 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 29: Graphene I

O 29.3: Vortrag

Dienstag, 15. März 2011, 11:45–12:00, WIL B321

Growth of graphene on heteroepitaxial Ir(111)-films — •Patrick Zeller¹, Sebastian Dänhardt¹, Stefan Gsell², Matthias Schreck², and Joost Wintterlin¹ — ¹LMU München, Department Chemie — ²Universität Augsburg, Institut für Physik

Monolayer graphene was epitaxially grown on thin iridium films by chemical vapor deposition (CVD) of ethylene. The films consist of a 150 nm thick (111)-oriented Ir layer on a Si(111) substrate with a 40 to 100 nm thick buffer layer of yttria-stabilized zirconia (YSZ) in between. The idea is to develop preparation techniques for epitaxial graphene without the need for bulk single crystals. The Ir films display a high crystalline quality with mosaic tilt and twist spreads lower than 0.2° [1]. The growth of graphene on these films was investigated by scanning tunneling microscopy (STM) and low-energy electron diffraction (LEED). We find the same four rotational graphene domains that exist on bulk Ir(111) single crystals, with rotational angles of 0°, 13.9°, 19.1°, and 30° [2,3]. STM data of the 13.9° and the 19.1° phase are reported here for the first time. The quality of the graphene and the formation of the various domains can be controlled by the growth conditions. In summary we demonstrate that the quality of the epitaxial graphene on the Ir films is comparable to Ir(111) single crystals. The findings may open a new economic route for epitaxial graphene synthesis.

[1] Gsell, S., et al., Journal of Crystal Growth 2009, 311, 3731. [2] N'Diaye, A., et al. New Journal of Physics 2008, 10, 043033. [3] Loginova, E., et al. Physical Review B 2009, 80, 085430.