Dresden 2003 – wissenschaftliches Programm

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O: Oberflächenphysik

O 24: Postersitzung (Epitaxie und Wachstum, Oxide und Isolatoren, Elektronische Struktur, Oberfl
ächenreaktionen, Adsorption an Oberfl
ächen, Organische Dünnschichten)

O 24.75: Poster

Mittwoch, 26. März 2003, 14:30–17:30, P1

Adsorption of nickel on self-assembled monolayers of oligophenylthiols:Effect of electron-induced cross-linking — •Yian TAI, Andrey Shaporenko, Michael Zharnikov, and Michael Grunze — Angewandte Physikalische Chemie, Universität Heidelberg, D-69120 Heidelberg

The problem of creation of organometallic structures can be successfully addressed by using model organic surfaces - self-assembled monolayers. The major difficulty in fabricating well-defined metallic films on the SAM surface is the penetration of the metal atoms to the SAM-substrate interface. Using a combination of complementary experimental techniques (HRXPS, NEXAFS spectroscopy, and ISS) and Ni as a test adsorbate, we demonstrate that such a penetration can be noticeably suppressed by electron-induced cross-linking of monomolecular films. For non-cross-linked SAMs, the formation of a Ni overlayer at the SAM-vacuum interface was only possible for a low Ni coverage through a reaction between Ni atoms and reactive terminal groups of the SAM constituents. However, even this layer was not stable - the Ni atoms penetrated through the SAM onto the SAM/substrate interface after a period of time. Contrary, for the crosslinked films, Ni films could be fabricated at the SAM-vacuum interface and kept there intact for a long period of time for both low and high Ni coverages.