Structural characterization, dielectric properties and electrical conductivity of ZnO nanoparticles synthesized by co-precipitation route

Abstract

The fabrication and characterization of zinc oxide (ZnO) nanoparticles (NPs) synthesized by a simple co-precipitation technique is reported in this work. The structural, morphological and dielectrical properties of the as-synthesized nanostructures were investigated. X-ray diffraction (XRD) pattern revealed that the obtained ZnO NPs are polycrystalline and crystallized in a single phase wurtzite with an average particle size of around 15 nm. The same size was found from scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HR- TEM). Dielectric measurements of ZnO NPs at different temperatures were carried out by impedance spectroscopy with respect to frequency. The high dielectric constant values of ZnO NPs at low frequencies range were observed owing to field rotation polarization and space charge. Both dielectric constant and dielectric loss of ZnO NPs showed decreasing behavior with frequency. This may be explained in terms of formation of boundaries between the nanoparticles of ZnO. The ac conductivity (σac) was found to be improved with temperature for T between 290 K and 409 K owing to the presence of defect centers and charge carriers.