Fe离子掺杂对ZnO压敏电阻性能的影响

Effect of Fe Ions Doping on the Properties of ZnO-Based Varistors

笔者主要研究了Fe^(3+)离子掺杂引入对ZnO基压敏电阻微观结构及综合电气性能的影响。实验结果表明,随着铁离子掺杂量的增加,ZnO压敏电阻的电位梯度持续不断升高,非线性系数先升高而后降低,漏流先减小再增大,压比逐渐增加。分析认为,掺杂少量Fe^(3+)时,可作为受主元素提高表面态密度,从而使非线性系数升高;随着掺杂量的增加,Fe^(3+)转变为Fe^(2+)进入ZnO晶粒内部,作为替位离子取代了部分Zn^(2+),由于r(Fe^(2+))>r(Zn^(2+)),该取代产生了压应力对ZnO晶格产生挤压,减小晶格空隙,从而阻止了其他掺杂离子的进入,表面态密度降低,非线性系数降低。

The author studies the influence of Fe^(3+)ions doping on the microstructure and comprehensive electrical properties of ZnO varistors.The research results show that with the increase of Fe^(3+)ions do-ping,the breakdown voltage gradient of the ZnO varistor continues to increase,the nonlinear coefficient first increases and then decreases,the leakage current first decreases and then increases,and the voltage ratio gradually increases.The analysis shows that when a small amount of Fe^(3+)is doped,it can be used as an acceptor element to increase the surface state densities,making the nonlinear coefficient increase;with the increase of the doping amount,Fe^(3+)transforms into Fe^(2+)and enters the ZnO crystal grains,as a substitute ion to replace part of Zn^(2+).Since the r(Fe^(2+))>r(Zn^(2+)),the substitution produces com-pressive stress to squeeze the Zno lattice,reduce the latice gap,thereby preventing the entry of other doped ions,reducing the densities of surface states and reducing the nonlinear coefficient.