Further analysis of high‐voltage ZnO varistor prepared from novel chemically aided method

Based on previous work, this study further investigated the high-voltage varistor materials prepared from chemically aided method. Microstructural characterization and electrical measurement results showed that the sample possessed more homogeneous microstructure and ultrahigh drop voltage per grain boundary (Vgb) than the conventional sample. The obtained ultrahigh value of Vgb is connected with the much lower donor concentration (Nd) and density of interface states (NIS) of the samples, which resulted from the increased number of active grain boundaries per unit volume. The improved homogeneous microstructure, together with the smaller grain size and narrower size distribution are essential to obtain high-voltage ZnO varistor.