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DF: Fachverband Dielektrische Festkörper

DF 9: Glass II

DF 9.1: Vortrag

Dienstag, 24. März 2009, 14:00–14:20, WIL B321

Ion conductivity of Lithium-Borate glass layers in the nanometer thickness range — •Gerd-Hendrik Greiwe, Frank Berkemeier, and Guido Schmitz — Institut für Materialphysik der Westf. Wilhelms-Universität Münster, Wilhelm-Klemm-Str. 10, 48149 Münster, Germany

Specific ion conductivities of thin layers of Lithium-Borate-glasses with the compositions x Li₂O · (1−x) B₂O₃, with x=0.15, 0.20, 0.25 and 0.35, are determined by impendance spectroscopy as a function of temperature and layer thickness. The glass layers are prepared by ion-beam-sputtering in the thickness range from 7 nm up to 1000 nm.

Previous measurements of our group demonstrated a significant increase of the specific conductivity with decreasing layer thickness. The increase is about three orders of magnitude and occurs for layers with a thickness under ≈100 nm. Recent measurements show that this finite size effect only arises for Aluminium Lithium electrodes. In the case of Aluminium electrodes no significant thickness dependence appears. Therefore diffusion of Lithium from the electrodes into the glass-layers must be assumed as reason for the effect. In the talk different models for the concentration profile of Lithium inside the glass-layers are discussed to explain the observed finite size effect.