This study focuses on the effects of doping Zn2BiVO6 and Co3O4 on the sintering and electrical properties of ZnO; where, ZZ consists of 0.5 mol% Zn2BiVO6 in ZnO, and ZZCo consists of 1/3 mol% Co3O4 in ZZ. As ZnO was sintered at about 800℃, the liquid phases, which are composed of Zn2BiVO6 and Zn2BiVO6-rich phases, were found to be segregated at the grain boundaries of sintered ZZ and ZZCo, respectively, which demonstrates that Vo·(0.33~0.36 eV) are formed as dominant defects according to the analysis of admittance spectroscopy. As Co3O4 is doped to ZZ, the resistivity of ZnO decreases to ~38%, while donor density (Nd), interface state density (Nt), and barrier height (Φb) increase twice higher than those of ZZ, according to C-V characteristics. This result harbingers that ZZCo and its derivative compositions will open the gate for ZnO to be applied as more progressive varistors in the future, as well as the advantageous opportunity of manufacturing ZnO chip varistors at lower sintering temperatures below 900℃.
