Synthesis of Doped ZnO Nanopowders Through Sucrose Protection Method and Its Use in Varistors Productions

Abstract

Doped ZnO nanopowders were successfully prepared by a novel wet-chemical method in the presence of sucrose and NH₄NO₃. Several analytic techniques such as x-ray diffraction, transmission electron microscopy and scanning electron microscope were used to make characterizations of the products. The results suggested that the doped ZnO powders were approximately spherical in shape with the diameter of the particles of about 25–45 nm. The as-synthesized powders were consolidated into dense varistors discs by compaction, sintering and evaluated for their electrical characteristics. Leakage current density was found to be about 0.93 μA/cm², and non-linear coefficients as high as 46.5 and breakdown field of about 595.8 V/mm were measured. The experimental results showed the advantage of the addition of sucrose and NH₄NO₃ for controlling grain size and improving electrical performance of the varistors.