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O: Oberflächenphysik

O 14: Postersitzung (Adsorption an Oberflächen, Epitaxie und Wachstum, Organische Dünnschichten, Oxide und Isolatoren, Phasenübergänge, Rastersondentechniken, Struktur und Dynamik reiner Oberflächen)

O 14.75: Poster

Montag, 8. März 2004, 18:00–21:00, Bereich C

Nanoscale Conductivity Spectroscopy on Solid Electrolytes using an Atomic Force Microscope — •Ahmet Taskiran, Andre Schirmeisen, Harald Fuchs, Frank Natrup, and Harmut Bracht — Physikalisches Institut and CeNTech, University of Muenster, Wilhelm-Klemm-Str.10, 48149 Muenster, Germany

Ion conducting solid materials play an important role as electrolytes in energy conversion systems, such as batteries and fuel cells, and also in electrochemical sensors. An important prerequisite for further progress in this field is a better understanding of the ion transport mechanisms on microscopic and nanoscopic length scales.

We are using atomic force microscopy (AFM) to measure the ionic conductivity in nanoscale volumes of dielectric glasses. The AFM is operated in the non-contact mode in vacuum. After a sudden change of the tip voltage, the relaxation of the electrostatic force between tip and sample is measured as a function of time. We measure these relaxation curves as a function of sample temperatures ranging from 100K to 675K. The observed relaxation curves are fitted well with a stretched exponential function and we can determine the activation energy of the conduction processes of the ions. First results indicate a good agreement of the activation energies for several prototype ionic glas conductors with values from macroscopic measurements. This method allows us to study fundamental processes of ionic transport and is in particular interesting for the investigation of nanostructured solid electrolytes.