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O: Fachverband Oberflächenphysik

O 72: Graphene: Adsorption, Intercalation and Doping

O 72.1: Poster

Mittwoch, 18. März 2015, 18:15–21:00, Poster A

Defects and oxygen adatoms on graphene — •Jan Gesenhues and Michael Rohlfing — Institut für Festkörpertheorie, Universität Münster, 48149 Münster, Germany

Oxygen adatoms on graphene are one of the ingredients of graphene oxide and are being discussed as building blocks to open a band gap in the Dirac cone of graphene. In our work we study graphene and oxygen adatoms within the theoretical framework of Tight-Binding and Density Functional Theory (DFT). The SIESTA program was used to carry out the DFT calculations.

In order to study defects in the graphene-layer a supercell approach is used. We take a closer look at the 5-7 defect and its effect on the electronic structure, in particular on the local density of states near the Fermi level. Furthermore we investigate the absorbtion of a single oxygen atom on the graphene-layer. Structure optimisations for various unit-cell sizes show that the oxygen atom equilibrium position is approximatly 2 Å  above the layer, also resulting in a perpendicular displacement of the surrounding carbon atoms of a few 0.1 Å. The effetcs on the electronic structure are studied in comparison with the undisturbed system via the (local) density of states.