Dresden 2017 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
O: Fachverband Oberflächenphysik
O 50: Semiconductor Substrates: Structure, Epitaxy, Growth and Adsorption
O 50.4: Poster
Dienstag, 21. März 2017, 18:30–20:30, P1A
Reaction channels of methanol on Si(001) studied by means of STM and XPS — •Patrick Kirsten, Christian Länger, and Michael Dürr — Institut für Angewandte Physik, Justus-Liebig-Universität, 35392 Giessen
Adsorption of organic molecules on silicon typically proceeds via an intermediate state. For diethyl ether, e.g., a dative bond between oxygen and silicon is formed in this intermediate, which was isolated at low surface temperatures on Si(001)[1]. A similar adsorption via a datively bonded intermediate state is proposed for alcohols on Si(001), however, the proton transfer associated with the transition from the intermediate into the final state is expected to proceed much faster than the energetically less favourable ether cleavage [2].
Indeed, when we performed XPS measurements after adsorption of methanol on Si(001) at different surface temperatures, the C 1s and O 1s spectra recorded both at 90 K and room temperature indicate dissociative adsorption and covalent bonding of the H atom and OCH3 fragment. In STM images taken after adsorption at room temperature, the end-bridge adsorption configuration is predominant. Changes in the adsorption configurations with surface temperature are interpreted in terms of a precursor-mediated reaction channel.
[1] Reutzel, et al., J. Phys. Chem. C 119, 6018 (2015).
[2] Kato, et al., J. Phys. Chem. B 105 10340 (2001).