Regensburg 2013 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 35: Poster Session I (Metal, semiconductor and oxide substrates: structure and adsorbates; Graphene)

O 35.34: Poster

Dienstag, 12. März 2013, 18:15–21:45, Poster B1

Low Temperature Scanning Tunneling Microscopy Study of Co-Phthalocyanine Molecules on Graphene/Ir (111) — •Samuel Bouvron, Philipp Erler, Stefan Ambrus, Elizabeta Cavar, and Mikhail Fonin — Fachbereich Physik, Universität Konstanz

Because of its influence on the electronic and transport properties of a molecule, the interaction between a molecule and a substrate is of crucial importance for possible applications in molecular electronic devices. Furthermore, the adsorption behavior of molecules on surfaces is decisive in a bottom up approach to build molecular electronics. We have investigated the adsorption of cobalt phthalocyanine (CoPc) molecules on epitaxial graphene on Ir(111) by means of low-temperature scanning tunneling microscopy(STM). The small mismatch between graphene and the Ir(111) surface lattice results in a highly ordered hexagonal moiré superstructure with a periodicity of 2.5 nm, making graphene/Ir(111) an interesting template for molecular self-assembly. Here we present the analysis of the nucleation and the early stage growth of CoPc islands on graphene on Ir(111). We report on a subtle competition between intermolecular interactions and substrate-adsorbate interactions for different coverages of CoPc molecules, varying from a submonolayer to a multilayer. Depending on the coverage, we observed different growth modes. At a monolayer coverage, the CoPc molecules arrange in an oblique close-packed structure, whereas at lower coverage a moiré-supported network consisting of ring-like units of six CoPc molecules is observed.