The grain and grain boundary impedance of sol–gel prepared thin layers of yttria stabilized zirconia (YSZ)

Separating grain and grain boundary impedance contributions of ion conducting thin films is a highly non-trivial task. Recently, it could be shown that long, thin, closely spaced, and interdigitally arranged electrodes enabled such a separation on pulsed laser deposited yttria stabilized zirconia (YSZ) thin films. In this contribution, the same approach was used to investigate YSZ layers prepared by the sol–gel route on sapphire substrates. Grain and grain boundary properties were quantified for layers between 28 and 168 nm thickness. Only for the thinnest of the investigated layers, a deviation from macroscopic bulk properties was found, which could be correlated to interfacial strain in the epitaxial layer. A dependence of the preferential orientation on the film thickness was found.