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O: Fachverband Oberflächenphysik

O 36: Posters: Bio/organic Molecules on Surfaces, Graphene, Solid/liquid interfaces, Metal Substrates, Electronic Structure Theory

O 36.45: Poster

Dienstag, 1. April 2014, 18:30–22:00, P1

Chemical and Electronic Modification of Graphene via Reactive Landing of Hyperthermal Molecular Ion Beams — •Girjesh Dubey¹, Stephan Rauschenbach¹, Roberto Urcuyo¹, Marko Burghard¹, and Klaus Kern^1,2 — ¹Max-Planck-Institute for Solid State Research, Heisenbergstrasse 1, Stuttgart — ²Institut de Physique de la Matiere Condensee, Ecole Polytechnique Federale de Lausanne, Switzerland

Tailoring the electronic properties of graphene by surface modification is of interest for switching devices and logic applications. However, chemical modification of graphene at stoichiometric densities is generally difficult, due to it’s low reactivity. One unique solution to this challenge is to collide energetic molecular ion beams (10-200 eV) at the surface of the sp²-hybridized basal plane. Upon impact, hyperthermal ion beams with energies considerably larger than that of a covalent bond (1-10 eV) are able to produce surface defects and create reactive fragments, leading to chemisorption. In this work, an electrospray ion beam deposition (ES-IBD) system is employed to carry out the modification in high vacuum. Singly charged cations of 4,4’-azobis(pyridine) are shown to reactively land on mechanically exfoliated and chemical vapor deposited graphene at moderate to high coverage. The resulting morphology, electronic transport properties, and vibrational spectra of the pyridine-functionalized surfaces are presented. These experiments highlight a facile approach for the controlled modification of graphene with a range of new molecules otherwise unreactive toward graphene by existing conventional methods.