Voronoi network model of ZnO varistors with different types of grain boundaries
- Solid State Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831-6030 (United States)
- Hubbell, Incorporated, The Ohio Brass Company, 8711 Wadsworth Road, Wadsworth, Ohio 44281 (United States)
- Metals and Ceramics Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831-6087 (United States)
Electrical transport in zinc oxide varistors is simulated using two-dimensional Voronoi networks. The networks are assumed to contain randomly distributed grain boundaries of three electrical types: (1) high nonlinearity (i.e., {open_quote}{open_quote}good{close_quote}{close_quote}) junctions; (2) poor nonlinearity (i.e., {open_quote}{open_quote}bad{close_quote}{close_quote}) junctions; and (3) linear with low-resistivity (i.e., ohmic) junctions. These type classifications are those found in experimental measurements. By varying the type concentrations, the simulated current density versus electric field ({ital J}{endash}{ital E}) characteristics can be made to conform to the different experimentally observed characteristics of ZnO varistors. These characteristics include the sharpness of switching at the transition between ohmic and nonlinear {ital J}{endash}{ital E} response (i.e., knee region), as well as the degree of nonlinearity. It is shown that the reduction of the nonlinearity coefficient of bulk varistors, relative to that of isolated grain boundaries, can be explained only by the presence of {open_quote}{open_quote}bad{close_quote}{close_quote} varistor junctions. {copyright} {ital 1996 American Institute of Physics.}
- Research Organization:
- Oak Ridge National Laboratory
- DOE Contract Number:
- AC05-96OR22464
- OSTI ID:
- 389271
- Journal Information:
- Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 11 Vol. 80; ISSN JAPIAU; ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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