Dresden 2003 – wissenschaftliches Programm
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O: Oberflächenphysik
O 12: Postersitzung (Struktur und Dynamik reiner Oberfl
ächen, Grenzfl
äche fest-flüssig, Nanostrukturen, Teilchen und Cluster, Halbleiteroberfl
ächen und Grenzfl
ächen, Zeitaufgelöste Spektroskopie, Rastersondentechniken, Methodisches)
O 12.28: Poster
Montag, 24. März 2003, 18:00–21:00, P1
Self-assembly of nano-colloidal gold films, characterized with AFM and spectroscopic ellipsometry — •Herbert Wormeester, Stefan Kooij, Martijn Brouwer, Arend van Silfhout, and Bene Poelsema — MESA+ Research Institute, University of Twente, Enschede, NL
Spectroscopic ellipsometry and AFM have been employed to characterise nanocolloidal gold films, self-assembled at amino (APTES-) derivatized Si/SiO2 surfaces. Optical properties are investigated ex-situ after drying as well as in-situ during the deposition. Random Sequential Adsorption governs the deposition, in agreement with the strong attractive interaction between the negatively charged colloidal particles and the possitively charged amino- end-groups at the substrate. Quantitative optical characterization of these inhomogeneous systems is not unambiguous. Conventional effective medium approximations will be shown not to apply. A so-called thin island film theory that treats the colloids as polarizabilities at the interface, taking into account both image charges and lateral interaction, gives excellent agreement between the optically and AFM determined coverages.