Regensburg 2007 – wissenschaftliches Programm
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DY: Fachverband Dynamik und Statistische Physik
DY 17: Glass II (joint session with DF)
DY 17.3: Vortrag
Dienstag, 27. März 2007, 15:10–15:30, H23
Finite size effect of the conductivity of sputtered lithium-borate glasses — •Frank Berkemeier, Mohammad Reza Shoar Abouzari, and Guido Schmitz — Westfälische Wilhelms-Universität Münster, Institut für Materialphysik, Wilhelm-Klemm-Str. 10, 48149 Münster
The specific dc-conductivity of ion-conducting, sputtered glass films of the compositions x Li2O · (1−x) B2O3, with x=0.15, 0.20 and 0.35, are determined by temperature dependent impedance spectroscopy. The thickness of the films varies between 7 nm and 1000 nm. In the case of relatively thick glass films (> 100 nm) each glass composition shows a specific dc-conductivity independent of the film thickness. For glasses with less than 20% alkali oxide, a significant increase of the specific dc-conductivity of about three orders of magnitude is observed, when decreasing the film thickness down to some nanometers. Three different models are suggested to explain this non-trivial ’finite size effect’: structural modifications at the interfaces between glass layer and metallic electrode, formation of space-charge regions at the interfaces, and the existence of ion-conducting pathways inside the glass layers. Computer simulations based on percolation theory are presented to show the link between the experimental data and the assumption of conducting clusters inside the glass films.