| Title |
Defects and Electrical Properties of ZnO-Co3O4-Cr2O3 with Sintering Temperature |
| Authors |
홍연우(Youn Woo Hong); 김유비(You Bi Kim); 이영진(Young Jin Lee); 김세기(Sei Ki Kim); 백종우(Jong Hoo Paik); 조만호(Man Ho Jo) |
| DOI |
https://doi.org/10.3365/KJMM.2014.52.12.1017 |
| ISSN |
1738-8228(ISSN), 2288-8241(eISSN) |
| Keywords |
electronic materials; ZnO varistor; sintering; defects; grain boundary |
| Abstract |
The defects and origin of the good varistor properties in the ZnO-Co3O4-Cr2O3 system were investigated by admittance spectroscopy, I-V characteristics, and impedance and modulus spectroscopy. Two kinds of defects were detected, but (0.27 eV) was identified as a major donor level by admittance spectroscopy. The ZnO grain resistivity of ~0.4 Ωcm was calculated but somewhat increased with sintering temperature. J-E characteristics with varistor behavior was seen in this system while the nonlinear coefficient α changed from 9 to 92 with sintering temperature. The single potential barrier of 0.64-1.01 eV at the grain boundary region was confirmed by impedance and modulus spectroscopy. The origin of a good varistor behavior in ZnO-Co3O4-Cr2O3 would be due to the formation and stabilization of a double Schottky barrier by the redox reaction of Co ions and the existence of small Cr ions in the grain boundaries. |