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 14.57: Poster

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

Electron Dynamics in Alkanethiol Self-Assembled Monolayers on Ultraflat Gold Films — •S. Dantscher, C. Kennerknecht, S. Schramm, D. Wolpert, and W. Pfeiffer — Physikalisches Institut, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany

For the self-assembly process of organic molecules like alkanethiols a very flat surface is necessary. The roughness on the atomic scale has to be minimized in order to create atomically flat terraces as large as possible. In this work thin gold films with a thickness from 500 to 700Å were evaporated under UHV conditions on freshly cleaved, heated (650K) mica sheets. After the evaporation process the surface only showed weak LEED spots which could be improved by sputtering and heating cycles. The enlargement of the terrace width up to 200nm was also confirmed by STM topographies. Adsorption of the alkanethiols took place in an inert gas atmosphere in order to prevent contamination of the gold surface. The technique of Time Resolved Two Photon Photo Emission was used to investigate the influence of the adsorbed SAM layer on electronic properties of the gold surface like work function and lifetime of excited states.