Effects of aluminum as dopants on the AC impedance and J-E behavior of ZnO-Bi/sub 2/O/sub 3/ ceramics

The effects of aluminum dopants on AC impedance and J-E characteristics of ZnO-Bi/sub 2/O/sub 3/ binary ceramics have been investigated. The results from J-E behavior and AC impedance analysis show that the presence of aluminum in the interface can be responsible for a decrease of the Schottky barrier height and an increase in grain boundary conductivity. Also, the model based on the resulting dispersion of the grain boundary resistance gives a better account of the shape of the semicircle in heterogeneous microstructures such as the ZnO-Bi/sub 2/O/sub 3/-Al/sub 2/O/sub 3/ system.