Interface effects in zinc oxide varistors
Zinc oxide varistors are electronic ceramic materials whose electrical behavior is dominated by grain boundary interface states. The unique properties of varistor ceramics are determined by the segregation of certain impurity atoms to the grain interface, creating electrical barriers to current flow. At low voltages, electrons transfer over these barriers by thermionic emission. At a critical voltage, electrons transferred over the grain interface have sufficient energy to create minority barriers (holes). These holes act to dramatically decrease the grain boundary electrical barriers leading to the observed rapid increase in current flow. Hole creation has recently been verified by optical means. Measurements of varistor degradation, varistor oxidation-reduction phenomena, and the behavior of ''primitive'' varistors with only modest current-voltage nonlinearity indicate that more than one parallel leakage path can control the varistor characteristics at lower currents. 19 refs., 12 figs.
- Research Organization:
- General Electric Co., Schenectady, NY (USA). Corporate Research and Development Dept.; Oak Ridge National Lab., TN (USA)
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 5328196
- Report Number(s):
- CONF-860714-1; ON: DE86014867
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360603 -- Materials-- Properties
42 ENGINEERING
420800* -- Engineering-- Electronic Circuits & Devices-- (-1989)
CHALCOGENIDES
CRYSTAL STRUCTURE
ELECTRICAL EQUIPMENT
ELECTRICAL PROPERTIES
EQUIPMENT
GRAIN BOUNDARIES
INTERFACES
MICROSTRUCTURE
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
RESISTORS
SEMICONDUCTOR DEVICES
SEMICONDUCTOR RESISTORS
ZINC COMPOUNDS
ZINC OXIDES