Berlin 2005 – scientific programme

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DS: Dünne Schichten

DS 22: Optische Spektroskopie dünner Schichten II

DS 22.8: Talk

Tuesday, March 8, 2005, 16:15–16:30, TU HS110

VUV spectroscopic ellipsometry of cytosine and functionalized cytosine using synchrotron radiation — •Y. Suzuki¹, O. D. Gordan¹, S. D. Silaghi¹, A. Schubert¹, W. R. Thiel¹, C. Cobet², W. Braun³, and D. R. T. Zahn¹ — ¹Institut für Physik, Technische Universität Chemnitz, D-09107 Chemnitz, Germany — ²Institute of Spectrochemistry and Applied Spectroscopy, D-12489 Berlin, Germany — ³Berliner Elektronenspeicherring-Gesellschaft für Synchrotronstrahlung mbH, D-12489 Berlin, Germany

DNA base molecules have potential as materials in organic electronics. However, there is so far only very little work on the properties of the DNA bases in the form of layers on inorganic substrates. Here we report on the optical properties, i.e. dielectric function, of cytosine and a functionalized variant, 1-allylcytosine, obtained by spectroscopic ellipsometry in the VUV photon energy range (4 - 9.5 eV). The samples were prepared by organic molecular beam deposition onto hydrogen passivated silicon substrates under ultra-high vacuum conditions. Typical thicknesses of the layers studied were in the range of 700-900 nm. The results reveal that the optical response changes significantly as a result of the addition of the functional group to the molecule, while density functional theory based ab-initio calculations predicted very similar absorption spectra.