Topic
Varistor
About: Varistor is a research topic. Over the lifetime, 4048 publications have been published within this topic receiving 38953 citations. The topic is also known as: voltage-dependent resistor & VDR.
Papers published on a yearly basis
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Papers
TL;DR: In this paper, the application of ZnO varistors has been treated in a systematic way in the literature and a detailed description of these parameters and their relation to microstructure and the processing of the varistor is provided.
Abstract: This paper deals with the application of ZnO varistors—an area which has not been treated in a systematic way in the literature. The paper starts with a brief description of the fundamental properties comprising the electrical behavior as well as the physics, chemistry, and microstructure of the varistor. These properties then form the basis for defining the application parameters that are directly related to the nonlinear current-voltage characteristics of the varistor. This paper provides a detailed description of these parameters and their relation to microstructure and the processing of the varistor. Finally, a discussion is presented on the reliability of the varistor by considering a grain-boundary defect model which explains both the instability and the stability under use conditions.
1,579 citations
TL;DR: It is demonstrated that, in addition to high permittivity, CaCu3Ti4O12 has remarkably strong nonlinear current–voltage characteristics without the addition of any dopants.
Abstract: The discovery of a giant dielectric constant of 10(5) in CaCu(3)Ti(4)O(12) has increased interest in this perovskite-type oxide Here we demonstrate that, in addition to high permittivity, CaCu(3)Ti(4)O(12) has remarkably strong nonlinear current-voltage characteristics without the addition of any dopants An intrinsic electrostatic barrier at the grain boundaries is responsible for the unusual nonlinear behaviour The nonlinear coefficient of CaCu(3)Ti(4)O(12) reaches a value of 900, which is even greater than that of the varistor material ZnO As a result, CaCu(3)Ti(4)O(12) may lead to efficient switching and gas-sensing devices
840 citations
TL;DR: In this article, a model is developed to describe the potential barriers which often occur at grain boundaries in polycrystalline semiconductors, where the resistance of such materials is determined by thermionic emission over these barriers.
Abstract: A model is developed to describe the potential barriers which often occur at grain boundaries in polycrystalline semiconductors. The resistance of such materials is determined by thermionic emission over these barriers. The dc grain‐boundary current density as a function of applied voltage is calculated using several forms for the density of defect states within the boundary region. In all cases, the currents are Ohmic at low voltages; they can attain a quasisaturated level at intermediate voltages, and they display a sharp bias dependence at high voltages. The details of the intermediate and high‐voltage characteristics are found to depend strongly on the grain‐doping density and on the density and energy distribution of defect states at the grain boundary. Contrary to previous assertions, we find that the large current‐voltage nonlinearities found in real materials are most likely associated with defect‐state densities that decrease above the zero‐bias Fermi level. The results of the model are compared ...
463 citations
TL;DR: In this article, a defect model for the grain-boundary barrier has been proposed to explain the phenomena of voltage instability/stability of the ZnO varistor, which is the key element of the proposed model is the zinc interstitials which are present in the depletion layer as excess zinc, arising from the non-stoichiometric nature of zinc.
Abstract: A defect model for the grain-boundary barrier has been proposed to explain the phenomena of voltage instability/stability of the ZnO varistor. The key element of the proposed model is the zinc interstitials which are present in the depletion layer as excess zinc, arising from the non-stoichiometric nature of ZnO. Both instability and stability have been described in terms of diffusion of these interstitials in the depletion layer, followed by chemical interactions with defects at the grain-boundary interface. Finally, a large body of experimental data is presented to indirectly validate the proposed defect model.
390 citations
303 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2026 | 1 |
| 2025 | 64 |
| 2024 | 68 |
| 2023 | 74 |
| 2022 | 131 |
| 2021 | 68 |