Influence of DC pre-stress on electrical and dielectric properties of zinc oxide ceramics

The degradation behavior of zinc oxide (ZnO) ceramics was investigated from the viewpoint of the electric and the dielectric properties, and thermally stimulated current before and after DC pre-stress. The nonlinear exponent α and activation energy obtained from the V-I characteristics decreased after DC pre-stress. In the low frequency range, the dielectric constant increased after DC pre-stress. Furthermore, a new TSC peak was measured on the high temperature side after DC pre-stress. A TSC peak increased with the increase of the the pre-stressing time and a peak temperature continuously shifted toward the high temperature. After measuring at high temperature for DC pre-stressing sample, the obtained values under DC pre-stressing condition were recovered to the initial values. These experimental results are analyzed on the basis of the deformation of the double Schottky barriers model in which the change of the barrier high and the depletion width is caused by the migration of donor ions under DC pre-stress