Berlin 2015 – wissenschaftliches Programm
O 33.9: Poster
Dienstag, 17. März 2015, 18:15–21:00, Poster A
Thickness, roughness and electronic structure characterisation of graphene using soft x-ray reflection spectroscopy — •Christine Jansing1, Hud Wahab2, Marc F. Tesch1,3, Markus Gilbert1, Andreas Gaupp1, Andrey Sokolov3, Dong Hee Shin4, Suk-Ho Choi4, Hans-Christoph Mertins1, Heiko Timmers2, Dominik Legut5, and Peter M. Oppeneer6 — 1Münster Uni. of Applied Sciences, D-48565 Steinfurt — 2School of Physical, Environmental and Mathematical Sciences, Uni. of New South Wales Canberra, Canberra, Australia — 3HZB, D-12489 Berlin — 4Dep. of Appl. Physics, College of Appl. Science, Kyung Hee Uni., Yongin 446-701, Korea — 5Nanotechnology Centre, Ostrava, Czech Republic — 6Depart. of Physics, Uppsala Uni., Uppsala, Sweden
X-ray reflection spectroscopy has been performed on graphene layers supported by different substrates across the C 1s absorption edge. Results confirm that the chemical vapour deposition onto copper foil has produced graphene of monolayer coverage. Graphene, deposited under the same conditions, transferred with a PMMA carrier to other substrate materials, has been measured to be significantly thicker. The interface- and the surface-roughness of the graphene layers have been determined. Structure in the measured reflection spectra can be correlated with ab-initio electronic band structure calculations and assigned to C 1s electron excitations. For the graphene layers transferred to a SiO2 substrate a feature is present that indicates excitation at an energy that is 1.8 eV less than the energy associated with the π* orbital. This finding is consistent with NEXAFS observations.