Regensburg 2019 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 25: Transport (Diffusion, conductivity, heat)

MM 25.5: Talk

Wednesday, April 3, 2019, 11:15–11:30, H46

Low-energy electron attachment induced transport - conductivities and the role of blocking electrodes — Anneli Hein, Martin Schäfer, and •Karl-Michael Weitzel — Philipps-Universität Marburg, Fachbereich Chemie

The charge carrier transport in an alkali ion conducting glass has been investigated by means of the charge attachment induced transport (CAIT) technique [1]. For the first time we describe the direct measurement of the absolute bulk conductivity and the activation energy for ion hopping in a glass by attachment of low-energy electrons to the front side of a glass, which is in contact with a single metal electrode at the backside [2]. The electron attachment experiment induces electro-diffusion of mobile cations towards the front side of the sample. In the limit of short time respectively little charge transported this approach allows measuring the conductivity as well as the activation energy of the glass, which agree well with reference measurements. In the limit of long time respectively considerable charge transported alkali depletion profiles evolve at the interface between the electrode and the glass. This eventually gives rise to the blocking of charge transport. A quantitative model for the evolution of "blocking electrode" characteristics is presented. The mechanism involves transient dielectric breakdown. [1] J. Martin, M. Gräf, T. Kramer, C. Jooss, M.J. Choe, K. Thornton, K.-M. Weitzel, PCCP, 19, 962, (2017) [2] A. Hein, M. Schäfer, K.-M. Weitzel, in preparation