Regensburg 2016 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

CPP: Fachverband Chemische Physik und Polymerphysik

CPP 51: Glasses (joint session CPP/DY, organized by DY)

CPP 51.8: Vortrag

Donnerstag, 10. März 2016, 11:45–12:00, H48

Electron bombardment induced cation transport in an ion conducting glass — •Anneli Hein, Jan Wiemer, and Karl-Michael Weitzel — Fachbereich Chemie, Philipps-Universität Marburg

The bombardment induced ion transport (BIIT) technique has been developed for measuring ionic conductivities and activation energies for ion hopping. The original version is based on attaching a cation beam to the sample (cation-BIIT) inducing the transport of such cations towards a grounded backside electrode. In the current work the BIIT technique is extended to electron bombardment (e- - BIIT). Here a low energy electron beam has been attached to a mixed sodium and potassium conducting borosilicate glass mounted on a single grounded backside electrode. Attachment of the electrons to the surface induces cation transport towards this surface. In the first part of the experiment current-voltage curves have been measured. The specific conductivities as well as the activation energy for ion hopping derived agree with cation-BIIT data. In the second part of the experiment we have performed a long term electron bombardment of the glass sample at -25 eV. Ex situ - after the bombardment - the sample has been analyzed by time-of-flight secondary ion mass spectrometry (ToF-SIMS). The depth profiles obtained from the ToF-SIMS analysis clearly demonstrate that sodium has been neutralized at the front side of the glass sample due to the recombination of electrons with sodium ions. Reduction of the less noble potassium ions appears to be suppressed. The electrochemical implications of this observation will be discussed.