CuO掺杂对WO_3压敏电阻微结构和电学性能的影响

Effects of CuO doping on the microstructure and electrical properties of WO_3 varistors

研究了CuO掺杂对WO3压敏电阻微结构和电学行为的影响,样品采用传统的陶瓷工艺制备。微结构通过扫描电子显微镜(SEM)观察,相结构和成分借助于X射线衍射(XRD)和能谱(EDS)进行分析。结果表明,微量的CuO掺杂能够促进WO3陶瓷的致密化和晶粒生长。根据I-V特性测量结果,0.2%(摩尔分数)CuO掺杂的WO3陶瓷具有线性伏安特性和极小的电阻率。CuO含量的继续增加使样品的非线性电学行为和电阻率又获得恢复,这是因为偏析于晶界处的CuO与两侧的晶粒形成了n-p-n型的双肖特基势垒。

The effects of CuO addition on the microstructure and electrical properties of the WO3 varistors were considered in this paper. The samples were prepared using a conventional mixed oxide route. The grain size and microstructure were investigated by scanning electron microscopy （SEM）. The phases and chemical composition were analyzed by X-ray diffraction （XRD） and energy dispersive spectroscopy（EDS）. The results indicate that minor addition of CuO promotes the densification and grain growth of WO3 ceramics. From the I-V measurer ments, the samples present linear current-voltage characteristic and the resistivity is quite low when doped with 0.2mol% CuO. A further increase in CuO content can recover the nonlinear electrical properties, this is because the excess CuO precipitates in the grain boundary and formed n-p-n type double Schottky barriers.