Relaxation peaks of ZnO varistors and their correlations with electrical properties. (19th February 2021)

• Record Type: Journal Article
• Authors: Zhao, Xia; Shi, Weidong; Zhang, Boyu; Guo, Men; Shen, Haibin
• Is Part Of: Japanese journal of applied physics. Volume 60:Number 3(2021)
• Publication Date: 2021-02-19
• Subjects: ZnO varistor -- dielectric response -- relaxation peak -- activation energy -- defect; Physics -- Periodicals; 621.05
• DOI: 10.35848/1347-4065/abe3a6
• Languages: English
• ISSNs: 0021-4922

Abstract

Abstract: Many dielectrics exhibit a (polarization) relaxation response when a time-varying electric field is applied. In some frequency bands, the amplitude of the polarization changes rapidly, with a significant dielectric loss; the maxima in the change rate are referred to as relaxation peaks. ZnO varistors exhibit a dielectric response with several relaxation peaks, but the relationship between the relaxation peaks and electrical properties has not been established. To understand this relationship, dielectric spectroscopy measurements of ZnO varistors were conducted in the temperature range of −110 °C to 200 °C in the frequency range of 10 −1 –10 6 Hz. By changing two important dopants of Bi2 O3 and Sb2 O3, four relaxation peaks, named Peak A, Peak B, Peak C, and Peak D, were detected. It was found that peaks A, B, and D are indispensable for higher nonlinearity and lower leakage current density. The detection of all four peaks implies that ZnO varistors possess excellent electrical properties, that is, a high breakdown field (235.2 V mm −1 ), nonlinear coefficient (76.2), and low leakage current density (0.065 μ A cm −2 ).