A method to reduce ZnO grain resistance and improve the intergranular layer resistance by Ca2+ and Al3+ co-doping

Abstract The promoting effect of Ca2+ (Ca) on the dissolution of Al3+ (Al) in crystal grains was studied. The electrical and microscopic properties of the samples were revealed by impedance analysis, C–V characteristic analysis and XRD. The Ca dopant can promote the Al solid solution to enter the grains and reduce the accumulation of Al in the grain boundary layer. The Ca doping can reduce the value of ZnO grain resistance by increasing the content of Al in the grains and increase the intergranular resistance by calcifying the grain boundaries. In this paper, there was an optimum ratio of Ca and Al doping (Ca/Al: 0.045/0.15), the grain resistance of the samples reaches the minimum value of 0.22 Ω and the intergranular resistance reaches the maximum value of 155.4 KΩ with the optimum ratio.