Dresden 2014 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 19: Graphene: Structural properties

O 19.10: Vortrag

Montag, 31. März 2014, 18:15–18:30, WIL C107

Epitaxial graphene nanoflakes on Au(111) and Ag(111) — •Julia Tesch1, Philipp Leicht1, Lukas Zielke1, Riko Moroni1, Bernd Illing1, Luca Gragnaniello1, Felix Blumenschein1, Elena Voloshina2, Lukas Hammerschmidt3, Lukas Marsoner Steinkasserer3, Beate Paulus3, Yuriy Dedkov4, and Mikhail Fonin11Fachbereich Physik, Universität Konstanz — 2Institut für Chemie, HU Berlin — 3Institut für Chemie und Biochemie, FU Berlin — 4Fritz-Haber-Institut der MPG, Berlin

In zig-zag edge terminated graphene nanoribbons or nanoflakes (GNFs), confinement of electrons is predicted to give rise to edge states with magnetic moments. However, the experimental observation of edge effects is impeded by the inevitable presence of substrates that interact with the flake edges, hence masking the GNFs' intrinsic properties. In the attempt of reducing the graphene substrate interaction, we use an entirely UHV based approach for the preparation of GNFs on Au(111) and Ag(111) surfaces allowing for flake sizes down to 10 nm. GNFs on Ir(111) are prepared by temperature programmed growth [1] and subsequently covered by deposition of several nm of Au or Ag. After post-annealing, the flakes diffuse through the Au or Ag film and form embedded or floating graphene flakes. In scanning tunnelling microscopy (STM), the edges of floating GNFs are found to be singly hydrogen terminated and entire flakes can be laterally displaced with the STM tip on both Au and Ag surfaces, suggesting a considerable reduction of graphene-substrate interactions compared to other metals. [1] Coraux et al., New J. Phys. 11, 023006 (2009)

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