소결온도가 ZnO-Co3O4-Cr2O3의 결함과 전기적 특성에 미치는 영향

• Published in: 대한금속·재료학회지, 52(12) Vol. 52; no. 12; pp. 1017 - 1023
• Main 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
• Format: Journal Article
• Language: Korean
• Published: 대한금속재료학회 31.12.2014; 대한금속·재료학회
• Subjects: defects; electronic materials; grain boundary; sintering; ZnO varistor; 재료공학
• ISSN: 1738-8228; 2288-8241
• DOI: 10.3365/KJMM.2014.52.12.1017

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.