In-situ formation of local inhomogeneities in semiconductors

The transport properties of ionic conductors such as α-AgI and Li_0.23La_0.69Fe_0.3Ti_0.7O₃ and of electronically conducting semiconductors such as α-Ag₂S and Ag_xWO₃ as a result of the application of voltages smaller than the decomposition voltage by two ionically blocking electrodes were investigated. The mobile ionic as well as the mobile electronic species are shifted from one electrode side to the other one. The change in the stoichiometric composition within the sample as a result of this transport process causes the formation of local inhomogeneities leading to changes in the electrical and optical properties. The experimental results also show that Nernst's law is not only valid for ionic conductors but also for semiconductors as well when a steady state is reached for ionically blocking electrodes. Paper presented at the 4th Euroconference on Solid State Ionics, Renvyle, Galway, Ireland, Sept. 13–19, 1997