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O: Fachverband Oberflächenphysik
O 61: Graphene II: Adsorption, Intercalation and Doping
O 61.6: Vortrag
Mittwoch, 9. März 2016, 16:15–16:30, S053
Coverage dependent evolution of electronic states of tetraphenyldibenzoperiflanthene (DBP) on HOPG and graphite — •Tobias Huempfner1, Tino Kirchhuebel1, Roman Forker1, Noriaki Kawakita2, Takashi Yamada2, Toshiaki Munakata2, and Torsten Fritz1,2 — 1Friedrich Schiller University, Institute of Solid State Physics, Helmholtzweg 5, 07743 Jena, Germany — 2Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka 560-0043, Osaka, Japan
We report on a combined study of the dye molecule tetraphenyldibenzoperiflanthene (DBP) deposited on HOPG and single crystalline graphite surfaces. The film growth is successively traced in situ via differential reflectance spectroscopy (DRS). This data is compared to ultraviolet photoelectron spectroscopy (UPS) as well as two photon photoemission (2PPE) measurements recorded at various coverages. All methods applied show that there are two different species of the DBP molecule that appear at certain film thicknesses. For low coverages, namely up to one monolayer (ML), the absorption gap of the molecules is smaller (low energy - LE) compared to coverages slightly above 1 ML (high energy - HE). For thicker films up to 10 ML the LE species is formed again and the film composition shifts continuously in favor of this species with increasing coverage. This study is assisted by structural data gained from low energy electron diffraction (LEED) and scanning tunneling microscopy (STM) that depicts a highly ordered first ML.