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O: Fachverband Oberflächenphysik
O 60: Poster Session IV (Solid/liquid interfaces; Semiconductors; Oxides and insulators; Graphene; Plasmonics and nanooptics; Electronic Structure; Surface chemical reactions; Heterogeneous catalysis)
O 60.14: Poster
Mittwoch, 16. März 2011, 17:30–21:00, P4
Investigation of Bis(phthalocyaninato)lutetium(III) on HOPG by STM, STS and DFT — •Lars Smykalla, Pavel Shukrynau, Marius Toader, and Michael Hietschold — Chemnitz University of Technology, Institute of Physics, Solid Surfaces Analysis Group, D-09107 Chemnitz, Germany
We report results obtained on ordered layers of Bis(phthalocyaninato)-lutetium(III) (LuPc2) on highly oriented pyrolytic graphite (HOPG) by using a variable temperature scanning tunneling microscope (STM) at 30K in UHV. These double decker phthalocyanine molecules were deposited by OMBE at low rates. Through slight annealing self-assembled highly ordered islands of LuPc2 were formed which show a close packed square structure governed by molecule-molecule interactions. Experiments with submonolayer coverage and multilayer coverage were carried out to investigate the epitaxy of the molecular layers on the substrate, the stacking behaviour and tilting of molecules relative to the layer. Very high resolved STM-images at negative bias voltage show intra-molecular features which are in very good agreement with the appearance of the highest occupied molecular orbital (HOMO) of LuPc2 gained by density functional theory (DFT). Tip-sample-distance-dependent tunneling spectroscopy was applied to study the electronic properties of the ordered molecular layers of LuPc2 on HOPG and the influence of the tip and the electric field. To identify the peaks in the normalized conductance spectra DFT calculations were performed and a comparison of the energy levels with STS shows a good agreement of the HOMO-LUMO-gap.