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O: Fachverband Oberflächenphysik
O 61: Graphene II: Adsorption, Intercalation and Doping
O 61.3: Talk
Wednesday, March 9, 2016, 15:30–15:45, S053
Core level shifts of doped graphene — •Ulrike A. Schröder1, Marin Petrović2, Timm Gerber1, Elin Grånäs3, Antonio J. Martínez-Galera1, Mohammad A. Arman3, Charlotte Herbig1, Joachim Schnadt3, Marko Kralj2, Jan Knudsen3,4, and Thomas Michely1 — 1II. Physikalisches Institut, Universität zu Köln, Germany — 2Institut za fiziku, Zagreb, Croatia — 3Division of Synchrotron Radiation Research, Lund University, Sweden — 4MAX IV Laboratory, Lund, Sweden
In X-ray photoemission spectroscopy, core level shifts of the carbon 1s photoelectrons are frequently monitored to investigate adsorption and intercalation on and underneath graphene. An understanding of their origin and magnitude are thus desirable both from a scientific and an applicational point of view. Through intercalation of metals and gases, the Dirac cone of graphene on Ir(111) can be shifted with respect to the Fermi level without becoming destroyed through strong hybridization. Upon such chemical doping with Cs, Eu, H, O, and Li, the carbon 1s core level shift displays a functional dependence on the graphene doping level. Of specific interest is the case of doping by Li, since for Li no phase separation takes place upon intercalation. Thereby, this core level shift can be monitored as a function of the intercalated amount. To first approximation, the core level shift may be described as a superposition of a rigid band shift, which is counteracted by a shift proportional to the transferred charge.