Silver in the form of AgNO3 was added to ZnO-based varistor ceramics prepared by the solid-state reaction method.The effects of AgNO3 on both the microstructure and electrical properties of the varistors were studied ...Silver in the form of AgNO3 was added to ZnO-based varistor ceramics prepared by the solid-state reaction method.The effects of AgNO3 on both the microstructure and electrical properties of the varistors were studied in detail.The optimum addition amount of AgNO3 in ZnO-based varistors was also determined.The mechanism for grain growth inhibition by silver doping was also proposed.The results indicate that the varistor threshold voltage increases substantially along with the AgNO3 content increasing from 0 to 1.5mol%.Also,the introduction of AgNO3 can depress the mean grain size of ZnO,which is mainly responsible for the threshold voltage.Furthermore,the addition of AgNO3 results in a slight decrease of donor density and a more severe fall in the density of interface states,which cause a decline in barrier height and an increase in the depletion layer.展开更多
基金supported by the National Natural Science Foundation of China (Nos.50571059 and 50615024)the Natural Science Foundation of Jiangsu Province,China (No.SBK200920379)the Program for New Century Excellent Talents in Chinese Universities (No.NCET-07-0536)
文摘Silver in the form of AgNO3 was added to ZnO-based varistor ceramics prepared by the solid-state reaction method.The effects of AgNO3 on both the microstructure and electrical properties of the varistors were studied in detail.The optimum addition amount of AgNO3 in ZnO-based varistors was also determined.The mechanism for grain growth inhibition by silver doping was also proposed.The results indicate that the varistor threshold voltage increases substantially along with the AgNO3 content increasing from 0 to 1.5mol%.Also,the introduction of AgNO3 can depress the mean grain size of ZnO,which is mainly responsible for the threshold voltage.Furthermore,the addition of AgNO3 results in a slight decrease of donor density and a more severe fall in the density of interface states,which cause a decline in barrier height and an increase in the depletion layer.
