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 24.59: Poster
Mittwoch, 26. März 2003, 14:30–17:30, P1
Adsorption of Fe(CO)5 on Si(111)7×7-surface — •Albena Petkova, Stefan Mühlbauer, and Hermann Froitzheim — Institut für Physikalische und Theoretische Chemie, Universität Erlangen-Nürnberg, Egerlandstr.3, 91058 Erlangen
We studied the adsorption of Fe(CO)5 on Si(111)7×7 surface between 100K and 700K using HREELS, AES, TDS and LEED. The three main losses visible in the HREEL-spectra at low temperatures (100K-300K) indicate dissociation of the Fe(CO)5 molecule resulting in a configuration of a linearly adsorbed FeCO in perpendicular position only. Using time resolved measurements (TREELS) we observed a spontaneous drastic decrease of the loss intensities without any structural change of the loss spectra after exceeding a critical dosage of 15L Fe(CO)5. The same sharp drop of the loss intensities occurred after annealing to 160K with lower dosage. At this temperature a desorption peak of FeCO was measured. But the loss spectra showed again the same structure which indicates that only a portion of the adsorbate has desorbed and that the adsorbate structure has not been changed by the desorption process. Both, the excess of the critical coverage as well the annealing process strongly suggest that only the electronic structure of the substrate can been changed.