Regensburg 2004 – wissenschaftliches Programm

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O: Oberflächenphysik

O 28: Postersitzung (Elektronische Struktur, Grenzfläche fest-flüssig, Halbleiteroberflächen und -grenzflächen, Magnetismus und Symposium SYXM, Methodisches, Nanostrukturen, Oberflächenreaktionen, Teilchen und Cluster, Zeitaufgelöste Spektroskopie)

O 28.20: Poster

Mittwoch, 10. März 2004, 16:00–19:00, Bereich C

Si(001) surface optical properties modified by organic functionalization and oxidation — •Andreas Hermann, Frank Groth, Wolf G. Schmidt, Kaori Seino, Martin Preuss, Patrick H. Hahn, and Friedhelm Bechstedt — Institut für Festkörpertheorie und Theoretische Optik, Friedrich-Schiller-Universität, Max-Wien-Platz 1, 07743 Jena, Germany

Tremendous efforts have been devoted to investigate the optical properties of clean Si(001) surfaces. Their reflectance anisotropy spectra (RAS) are now well understood in terms of defects and transitions between surface states as well as surface-modified bulk wave functions [1]. Far less is known about the modifications of the surface optical response by chemical reactions. Inspired by recent experiments [2] we study numerically the influence of organic functionalization with phenanthrenequinone and layer-by-layer oxidation on the RAS spectrum of Si(001). The calculations are performed using the gradient-corrected density functional theory (DFT-GGA) in conjunction with non-normconserving ultrasoft pseudopotentials and a plane-wave basis. The optical spectra are determined in the independent-particle approximation from all-electron wave functions obtained by the projector-augmented wave (PAW) method.

[1] T. Yasuda et al., Phys. Rev. Lett. 74, 1995, 3431; R. Shioda, J. van der Weide, Phys. Rev. B 57, 1998, R6823; W.G. Schmidt, F. Bechstedt, J. Bernholc, Phys. Rev. B 2001, 63, 5322.

[2] C.A. Hacker, R.J. Hamers, J. Phys. Chem. B 107, 2003, 7689; T. Yasuda et al., Phys. Rev. Lett. 87, 2001, 037403.