Regensburg 2010 – scientific programme
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O: Fachverband Oberflächenphysik
O 47: Metal substrates: Adsorption of organic / bio molecules V
O 47.4: Talk
Wednesday, March 24, 2010, 11:15–11:30, H36
Sub-monolayer growth of CuPc on Cu(111) — •Benjamin Stadtmüller1,2, Ingo Kröger1, Friedrich Reinert2, and Christian Kumpf1 — 1Forschungszentrum Jülich (IBN-3) & JARA-FIT — 2Exp. Physik II, Univ. Würzburg
The geometric arrangement of organic molecules within the first monolayer adsorbed on a metal surface has crucial influence on the interface properties as well as on the growth behavior of the following molecular layers. We studied the sub-monolayer growth of the model system copper-II-phthalocyanine (CuPc) on the Cu(111) surface using high resolution low energy electron diffraction (SPA-LEED) and photoelectron spectroscopy (UPS). This system is of highest interest since phthalocyanine molecules show an unusual intermolecular repulsion upon adsorption on the Ag(111) surface [1]. This is also discussed in the contributions of I. Kröger and C. Kleimann. On Cu(111), however, the alignment of the molecules indicates an attractive intermolecular interaction at sub-monolayer coverages. At low coverages the molecules align in linear chains of different length. At higher coverages they start to form islands having a commensurate structure. UPS-measurements show a new electronic state close to the Fermi level which indicates charge transfer (i.e. chemical interaction) between the molecules and the substrate. This breaks the 4-fold symmetry of the molecule and consequently influences the molecular order. From the comparison of results found for CuPc on Cu(111), Ag(111) and Au(111) we gain insight the influence of the substrate on the intermolecular interaction.
[1] Stadler et al., Nature Physics 5, 153 (2009)