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DF: Dielektrische Festkörper

DF 5: Glass I (together with division ‘Dynamics and Statistical Physics’ [DY])

DF 5.3: Vortrag

Dienstag, 28. März 2006, 10:30–10:50, M{\"U}L Elch

Ionic Motion in Ion Beam Sputtered Borate Glasses — •Frank Berkemeier, Reza Abouzari, Tobias Stockhoff, and Guido Schmitz — Westfälische Wilhelms-Universität, Institut für Materialphysik, Wilhelm-Klemm Straße 10, 48149 Münster

Ion-conducting, amorphous thin films with a thickness of 20 − 500 nm are prepared by ion beam sputtering using glass targets of the compositions 0.2 A₂O · 0.8 B₂O₃, with A = Li, Na, Rb. The glass layers are deposited on a silicon substrate between two sputtered electrodes of Ag, Al, or Al-Li alloy. TEM cross-section investigations show a homogeneous thickness and a homogeneous, amorphous structure of the films. Chemical analysis, performed by EELS, gives alkali oxide concentrations comparable to those of the target material. Temperature-dependent impedance spectroscopy allows to differentiate between different electrical properties of the samples and to determine the specific dc-conductivities of the glass layers. Layers thicker than 100 nm show dc-conductivities which are about one order of magnitude higher than those of the target materials and activation enthalpies about 20 kJ mol⁻¹ less compared to the targets. Additionally, layers thinner than 100 nm show a non-trivial increase in dc-conductivity with decreasing film thickness, which we attribute to the increasing influence of the glass-electrode interfaces.