The Effects of Cu Dopant on the Microstructure and Non-Ohmic Electrical Properties of ZnO Varistors

Abstract

The doping effects of Cu on the microstructure and non-ohmic electrical properties of ZnO varistors were studied. Addition of Cu2O can enhance the ZnO grain growth during sintering. The SEM and EDS results revealed that the added Cu mainly distributed in the grain boundary and spinel phases of ZnO varistors. The Cu2O addition increased the both of grain and grain boundary resistances. However it decreased the non-ohmic electrical characteristics of ZnO varistors, which is a good agreement with similar findings on Ag2O additions, but contrasts to the reports of good non-ohmic electrical property which found on binary Cu doped ZnO varistors.

The Electrical Properties and Impedance Analysis of ZnO Varistors Doped with Different Cu₂O Contents

“…In contrast, Zhou et al [8] reported the Cu-doped ZnO samples shows linear I-V characteristics. Fan et al [11] reported that the Cu 2 O addition could deteriorate the electrical properties of ZnO varistor. However, the effects of monovalent Cu on the electrical characteristics of ZnO based varistors need to be further investigated.…”