Regensburg 2013 – scientific programme

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O: Fachverband Oberflächenphysik

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

O 35.87: Poster

Tuesday, March 12, 2013, 18:15–21:45, Poster B1

Organic molecular self-assembly on epitaxial graphene — •Alexei Nefedov¹, Wenhua Zhang², Michael Naboka¹, Hikmet Sezen¹, Liang Cao², and Christof Woell¹ — ¹Institute of Functional Interfaces, Karlsruhe Institute of Technology, Leopoldshafen, Germany — ²National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, PRC

The adsorption of organic molecules as pentacene (Pn) and terephthalic acid (TPA) on a single layer of graphene grown epitaxially on Ni(111) has been investigated by means of near-edge X-ray absorption fine structure (NEXAFS) spectroscopy and X-ray photoelectron spectroscopy (XPS) at room temperature. The assignment of the NEXAFS-resonances was aided by ab-initio calculations by StoBe package. For coverages up to a monolayer the molecular plane of TPA adopts a parallel orientation with regard to the epitaxial graphene (EG) layer. Deprotonantion of TPA molecules at one monolayer coverage can be excluded. For TPA multilayers, the molecular plane is tilted on average by approximately 45° with respect to the sample surface. Pentacene molecules demonstrate a dependence of their orientation and electronic structure on the coverage. The observed effects will be discuss in detail during presentation.