Semiconductors Elaboration/ZnO Based Varistors for Improving of Stability and Reliability of Electrical Systems Applications by Using the Rare-Earths

摘要

In this work we suggest a technological participation to improve the electrical behaviour and the reliability of the polycrystalline non-linear electronic devices ,ZnO, based varistor, to be used to protect the electrical and electronic systems against the sudden increasing of high voltage on Electrical loads. This work includes the effect of Rare-Earth Metals (Er, Ce, Pr, Y, Dy), for different temperature firing. The nonlinearity factor a (= d(dLnl)/(dLnv)) ),I, and V are the current and Voltage respectively, the grains size, the junction which separate the tow grains, are all responsible of the electrical behaviour of this material and they lead to threshold voltage stability and the density of leakage current. Adding -as impurity- to the studied sample each of: Cerium (Ce), Yttrium (Y), Erbium (Er), Praseodymium (Pr), and Dysprosium (Dy) as a rear-metal earth, varying of temperature firing, it is concluded that each of them is positively affect on both of grain figure and nonlinearity factor, which lead to stability of nonlinear devices and improve electrical and electronic system's behaviour and reliability.