Regensburg 2010 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 14: Metal substrates: Adsorption of organic / bio molecules II

O 14.5: Vortrag

Montag, 22. März 2010, 16:00–16:15, H36

Metal/SAM/Metal junctions studied from first principles — •Jan Kučera and Axel Groß — Institute for Theoretical Chemistry, Ulm University, D-89069 Ulm, Germany

There is currently a strong interest in sandwich structures made of self-assembled monolayers (SAMs) between two metal layers (M/SAM/M) because of their potential in future nanoelectronics [1]. Recently, a M/SAM/M/SAM/M “double decker” junction was realized with two 4-mercaptopyridine SAMs sandwiched between an Au electrode and Pd and Pt monolayers [2]. We have performed periodic electronic structure calculations based on density function theory (DFT) to describe various phenomena playing a role in hybrid systems such as Au/SAM, Au/SAM/Pd, and Au/SAM/Pd/SAM/Pt with the SAMs consisting of the bifunctional thioaromatics 4-aminothiophenol or 4-mercaptopyridine [1-3]. Based on the calculated local density of states (LDOS) of the metal layers, possible explanations for experimental results will be provided which show a reduced DOS at the Fermi energy [2]. In addition, the role of van der Waals forces on the structure and stability of the SAMs has been addressed by performing DFT calculations with semi-empirical corrections for dispersion effects.

[1] M. Manolova et al., Adv. Mater. 21, 320 (2009)

[2] F. Eberle et. al., Angew. Chem., accepted for publication.

[3] J. Kučera and A. Groß, Langmuir 24, 13985 (2008)