Berlin 2015 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 32: Graphene: Growth & intercalation (O with HL/TT)

HL 32.2: Vortrag

Dienstag, 17. März 2015, 10:45–11:00, MA 041

Graphene induced faceting of Ir(557) — Christian Witt, Michael Horn-von Hoegen, and •Frank-J. Meyer zu Heringdorf — University Duisburg-Essen, Faculty for Physics and CENIDE, Lotharstrasse 1, 47057 Duisburg

With its great application potential due to the unique electronic structure and the mechanical properties, graphene holds promise for future carbon-based device architectures. Lately, a lot of effort has been invested into the growth of graphene on metal surfaces, due to the possibility to separate the graphene from the surface after growth. In some cases, however the interaction between graphene and the substrate, in conjunction with the elevated sample temperatures, results in a modification of the substrate surface morphology during growth. Here we investigate the modification of a regularily stepped Ir(557) surface during catalytic growth of graphene at various ethylene pressures and temperatures with low energy electron microscopy. Ir(557) is a vicinal (111) surface with a miscut of 9.45° in [001] direction. We find simultaneous growth of graphene flakes and nano-ribbons, depending on ethylene pressure and sample temperature. The nano-ribbons grow exclusively along the steps. Both, flakes and nano-ribbons, induce a faceting of the surface during growth. An intercalation of oxygen between the graphene and the faceted surface does not affect the already present facets. The orientation of the facets were determined by reciprocal space mapping and (ex-situ) AFM measurements.