Current-Voltage and Impedance Characteristics of ZnO-Zn₂BiVO₆-Co₃O₄Varistor with Temperature

Abstract

This study introduces the characteristics of current-voltage (I-V) and impedance variance for ZnO-Zn 2 BiVO 6 -Co 3 O 4 (ZZCo), which is sintered at 900 o C, according to temperature changes. ZZCo varistor demonstrates dramatic improvement of non-linear coefficient, α = 66, with lower leakage current and higher insulating resistivity than those of ZZ (ZnO-Zn 2 BiVO 6 ) from the aspect of I-V curves. While both systems are thermally stable up to 125 o C, ZZCo represents a higher grain boundary activation energy with 1.05 eV and 0.94 eV of J-E-T and from IS & MS, respectively, than that of ZZ with 0.73 eV and 0.82 eV of J-E-T and from IS & MS, respectively, in the region above 180 o C. It could be attributed to the formation of (0.41~0.47 eV) as dominant defect in two systems, as well as the defect-induced capacitance increase from 781 pF to 1 nF in accordance with increasing temperature. On the other hand, both the grain boundary capacitances of ZZ and ZZCo are shown to decrease to 357 pF and 349 pF, respectively, while the resistances systems decreased exponentially, in accordance with increasing temperature. So, this paper suggests that the application of newly formed liquid phases as sintering additives in both Zn 2 BiVO 6 and the ZZCo-based varistors would be helpful in developing commercialized devices such as chips, disk-type ZnO varistors in the future. Received: Nov. 17, 2016, Accepted: Nov. 29, 2016 This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License(http://creativecommons.org/ licenses/bync/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.