The electrical properties of the ZnO varistors were demonstrated here to be affected by the sintering temperature. The variation of the non‐ohmic behavior with sintering temperature was indicated from I‐V and C‐V measurements to be a result of the changes of the interface defect density at the grain boundaries and the donor concentration in the ZnO grains. A shallow Schottky barrier was formed as a result of a low interface defect density, which was caused by losing the liquid‐phase sintered materials, such as Bi2O3, when the metal oxide additives along the grain boundaries were sintered at a high temperature. The dielectric characteristic of the ZnO varistors was also affected by the sintering temperature. From the dielectric loss analysis and the complex‐plane analysis it was found that there were two intrinsic defects, V0. and Zni.., within the ZnO varistors. The natures of these defects as a function of sintering temperature were also mentioned.

Influence of Sintering Temperature on Electrical Properties of ZnO Varistors. Bai, S.N., Tseng, T.Y.: Journal of Applied Physics, 1993, 74[1], 695