Title :
Electrical properties of ZnO-Bi2O3 two-layer composites
Author :
Ieda, M. ; Suzuoki, Y. ; Nakagawa, M. ; Mizutani, T.
Author_Institution :
Dept. of Electr. Eng., Nagoya Univ., Japan
Abstract :
A ZnO-Bi2O3 two-layer composite formed by RF sputtering was studied as a model of a single grain boundary in a ceramic ZnO varistor to clarify the mechanism of degradation and highly nonlinear conduction. The voltage-current characteristics, capacitance-voltage characteristics, and thermally stimulated currents (TSC) were measured. The breakdown voltage of the specimens can be controlled by changing the thickness of the Bi2O3 layer. TSC curves for the reverse-bias poling voltage flowed in the direction of depolarization at temperatures below 120°C but in the direction of polarization above 120°C. It is concluded that the mechanism of nonlinear conduction for the composite is related to the accumulation of trapped electrons in the Bi2O3 layer and negative charges at the ZnO-Bi2O3 interface
Keywords :
bismuth compounds; dielectric polarisation; electric breakdown of solids; electron traps; space-charge-limited conduction; sputtered coatings; thermally stimulated currents; varistors; zinc compounds; RF sputtering; SCL conduction; TSC curves; ZnO-Bi2O3; breakdown voltage; capacitance-voltage characteristics; ceramic ZnO varistor; degradation; depolarization; negative charges; nonlinear conduction; polarization; reverse-bias poling voltage; single grain boundary; thermally stimulated currents; trapped electrons; two-layer composites; voltage-current characteristics; Bismuth; Capacitance-voltage characteristics; Ceramics; Grain boundaries; Radio frequency; Sputtering; Thermal degradation; Varistors; Voltage; Zinc oxide;
Conference_Titel :
Properties and Applications of Dielectric Materials, 1988. Proceedings., Second International Conference on Properties and Applications of
Conference_Location :
Beijing
DOI :
10.1109/ICPADM.1988.38371
