测量了ZnO-Bi2O3系压敏陶瓷在不同温度下的介电频谱,基于压敏陶瓷介电特征损耗峰起源于耗尽层内本征缺陷电子松弛过程的理论,计算了ZnO的本征缺陷结构,并进一步求出了晶界的微观电参数和宏观单晶界击穿电压.单晶界击穿电压的理论值与实验测量值符合得很好,这表明本文建立的基于介电谱计算本征缺陷的方法是有效的.
Dielectric frequency spectra of ZnO-Bi2O3 based varistor ceramics were measured in the frequency range of 10^-2 Hz-10^6Hz from -100℃ to 20℃ by Novocontrol broadband dielectric spectrometer. The intrinsic defect structure of ZnO was calculated according to the theory which assumes that characteristics dielectric loss peaks of ZnO varistor ceramics origin from electronic relaxation process of intrinsic defects in depletion layer. At the same time the micro-electric parameters of grainboundary and the single grainboundary breakdown voltage Vb were obtained. The accordance of theory with experiment in Vb value indicates that the method to calculate grainboundary electronic structure by dielectric spectroscopy proposed in this paper is resonable.