Regensburg 2004 – wissenschaftliches Programm

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O: Oberflächenphysik

O 14: Postersitzung (Adsorption an Oberflächen, Epitaxie und Wachstum, Organische Dünnschichten, Oxide und Isolatoren, Phasenübergänge, Rastersondentechniken, Struktur und Dynamik reiner Oberflächen)

O 14.74: Poster

Montag, 8. März 2004, 18:00–21:00, Bereich C

Chemical Reactivity Properties of Thiol Self-Assembled Monolayers on Au(111) observed by STM/ AFM — •Till Hagedorn, Andre Schirmeisen, Lifeng Chi, and Harald Fuchs — Physikalisches Institut & CeNTech, University of Muenster,Wilhelm-Klemm-Str. 10, 48149 Muenster, Germany

In this work self-assembled monolayers of thiols on Au(111) were investigated with STM/ AFM methods under UHV conditions p≈ 10⁻¹⁰ mbar) at room temperature. The preparation is done by chemisorbtion in a 3 mM ethanolic solution of 11-Mercapto-1-undecanol (SH-(CH₂)₁₁-OH) outside the UHV chamber. Heating at approximately 120 ^∘C under UHV conditions lowers the density of thiole molecules at the Au(111) surface which results in an alignment of the thiole molecules parallel to the Au surface. The focus is on the properties of the line-structure phase with the lowest surface density [1][2]. Al clusters are evaporated on the regions of the thiol line-structure in order to investigate where the Al atoms adsorb. With the STM we find that the Al clusters preferably adsorb onto the sulphur head of the thiol. Additionally, we investigate in AFM measurements with Al functionalized tips the forces acting on different parts of the thiol chain.

[1] Poirer G.E. Langmuir 1999, 15, 1167-1175

[2] Staub R., Toerker M., Fritz T., Schmitz-Hübsch T., Sellam F., Leo K. Langmuir 1998, 14, 6693-6698