Regensburg 2002 – wissenschaftliches Programm
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O: Oberflächenphysik
O 13: Postersitzung (Adsorption an Oberfl
ächen, Elektronische Struktur, Magnetismus in reduzierten Dimensionen, Epitaxie und Wachstum, Halbleiteroberfl
ächen und -grenzfl
ächen, Organische Dünnschichten)
O 13.14: Poster
Montag, 11. März 2002, 18:00–21:00, Bereich C
Acrylonitrile on Si(001)-2X1 studied by scanning tunneling microscopy and synchrotron radiation electron spectroscopies — •Stefan Kubsky1, Martin Kneppe2, Ulrich Köhler2, Fabrice Bournel1, Georges Dufour1, Jean-Jaques Gallet1, and Francois Rochet1 — 1Laboratoire de Chimie Physique, Matiere et Rayonnement, Universite Pierre et Marie Curie, Paris, France — 2Experimentalphysik IV, Ruhr-Universität Bochum, Bochum,Germany
As the grafting of monomolecular organic layers on clean silicon surfaces opens the way to the creation of interesting nanostructures, the chemistry of various functionalities with Si(001) is now systematically studied. Here we examine the adsorption modes of H2C=CH−C≡N at 300 K, which should depend on the competition between the two functionalities and on their conjugation. To better understand such a complex system, we use scanning tunneling microscopy (STM) and synchrotron radiation electron spectroscopies in combination. X-ray photoemission and absorption spectroscopies show that the molecule chemisorbs non-dissociatively with a high sticking coefficient. X-ray absorption data strongly suggest that one of the major reaction products adopts a flat lying geometry, involving the bonding of the two outer skeleton atoms to two silicon dangling bonds. This bonding, allowed by conjugation, is directly confirmed by STM images obtained at low coverages, which, moreover, demonstrate that the molecule bridges two adjacent dimer rows, inducing a strong local dimer buckling.