Electrical characterization of ceramic voltage sensors by impedance spectroscopy

yCeramic voltage sensors exhibit well-defined granular structure in which the semiconducting grains are separated by thin insulating intergranular layers. The electronic properties of ceramic voltage sensors are primarily influenced by double schottky barriers located in the overlapping regions of grains and intergranular layers. To differentiate between varying contributions from grains, grain boundaries, intergranular layers and electrode interfaces, impedance spectroscopy has been widely used in the literature. The difference in impedance responses originating from different regions of granular ceramics is understood in terms of equivalent circuits involving resistive and capacitive elements. In recent years, we have studied the impedance spectra of ZnO and TiO2 based voltage sensors which helped us to model the conduction processes in terms of most appropriate equivalent circuits. Some of our experimental results and its analysis will be highlighted in this paper.