Berlin 2012 – scientific programme
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O: Fachverband Oberflächenphysik
O 4: Graphene I
O 4.6: Talk
Monday, March 26, 2012, 11:45–12:00, MA 041
SPA-LEED study of strain state of single layer graphene on Ir(111): hysteretic behaviour of lattice parameter and wrinkle formation — •C. Klein1, H. Hattab1, A. T. N'Diaye2, D. Wall1, G. Jnawali1, J. Coraux3, C. Busse2, R. van Gastel4, B. Poelsema4, T. Michely2, F.-J. Meyer zu Heringdorf1, and M. Horn-von Hoegen1 — 1Department of Physics, Universität Duisburg-Essen — 2II. Physikalisches Institut, Universität zu Köln — 3Institut Néel, CNRS-UJF, Grenoble Cedex 9, France — 4Physics of Interfaces and Nanomaterials, MESA+ Institute for Nanotechnology, University of Twente, Enschede, The Netherlands
Employing high resolution low energy electron diffraction (SPA-LEED) the lattice parameter of single layer graphene on Ir(111), prepared by thermal decomposition of ethylene at 1530 K, was studied. We analyzed the strain state and the wrinkle formation kinetics as function of temperature. Using the moiré spot separation as a magnifying mechanism for the difference in the lattice parameters between Ir and graphene, we achieved an unrivalled relative precision of ca. 0.1 pm for the graphene lattice parameter. Our data reveals a characteristic hysteresis of the graphene lattice parameter which is explained by the interplay of reversible wrinkle formation and film strain. We show that epitaxial graphene on Ir(111) always exhibits residual compressive strain at room temperature, and provide important guidelines for strategies to avoid wrinkling.
Hattab et. al., Nano Letters (under revision, Nov. 2011)