Berlin 2005 – scientific programme

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HL: Halbleiterphysik

HL 57: Poster IIa

HL 57.3: Poster

Tuesday, March 8, 2005, 16:30–19:00, Poster TU E

Density of Occupied States in Layers of DNA Bases on H-passivated Si(111) — •S. Seifert, G. Gavrila, S.D. Silaghi und D.R.T. Zahn — Institut für Physik, Technische Universität Chemnitz,D-09107 Chemnitz

The (opto-)electronic properties of the four DNA bases adenine, cytosine, guanine and thymine may suggest the possibility to use them in bio-electronic applications. There is, however, little knowledge or experimental data regarding the electronic structures of these materials. Therefore a systematic photoelectron spectroscopy study was performed for DNA base layers. Such layers were prepared with various thicknesses by organic molecular beam deposition on H-passivated Si(111) under ultra high vacuum conditions. Ultraviolet photoelectron spectroscopy (UPS) with an excitation energy of 21.2 eV (He I radiation) in normal emission was employed to determine the density of occupied states (DOOS) of these layers. The results are compared to previously obtained information on the combined density of states obtained by variable angle spectroscopic ellipsometry and the calculated electronic states of single molecules.