Influence of chromium oxide additive on electrical characteristics of ZnO varistor

The effect of chromium oxide (Cr/sub 2/O/sub 3/) additive on the electrical characteristics of ZnO-Bi/sub 2/O/sub 3/-Sb/sub 2/O/sub 3/-based ZnO varistors in the prebreakdown and breakdown regions was studied by comparing the electrical properties of three different system samples. When Cr/sub 2/O/sub 3/ is added into ZnO varistor, the breakdown voltage and the nonlinearity coefficient decrease. Cr/sub 2/O/sub 3/ increases the leakage current in the breakdown region and reduces the voltage ratio in the breakdown region, which leads to bad electrical characteristics. C-V characteristics show that this deterioration is related to lower barrier height, donor concentration, and interface defect density of the intergranular layer of the O varistor.