Regensburg 2010 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 26: Poster Session

MM 26.82: Poster

Tuesday, March 23, 2010, 14:45–16:30, Poster C

Morphology of Graphene Layers on Ir(111) Studied by SPA-LEED — •Dennis Meyer, Hichem Hattab, Giriraj Jnawali, Dirk Wall, Frank-Joachim Meyer zu Heringdorf, and Michael Horn-von Hoegen — Fakultät für Physik und Center for Nanointegration Duisburg-Essen (CeNIDE), Universität Duisburg-Essen, 47057 Duisburg, Germany

We used SPA-LEED to investigate the morphology of graphene layers on Ir(111) at different growth temperatures. The decomposition of ethylene at 1040°C results in a highly oriented graphene layer. The LEED pattern solely shows the moiré spots surrounding each Ir(111) integer order spot. These satellites arise from the 10% mismatch between the two hexagonal lattices. Between 600°C and 1000°C we observe in addition a broad distribution of almost randomly oriented graphene domains which cover the majority of the surface. These domains give rise to broad arcs in the LEED pattern. There is no commensurate order with respect to the Ir(111) substrate. Another minority graphene domain is rotated by 30° with respect to the Ir(111) lattice, locks in in registry with the substrate, and gives rise to a sharp spot between the moiré patterns of the ordered phase.