Structural, electric modulus and complex impedance analysis of ZnO at low temperatures

Abstract

A low cost and low-temperature co-precipitation process was used to synthesize zinc oxide(ZnO) nanoparticles. The synthesized sample was characterized by x-ray diffraction(XRD), field emission scanning electron microscopy (FE-SEM), FTIR and UV–visible spectrum at room temperature. The electrical properties at a low-temperature range between 140 K and 280 K are also reported. The dielectric parameters and the complex impedance spectra were analyzed in the frequency range from 20 Hz to 2 MHz at a low temperature ranging from 140 K to 280 K. The AC conductivity was estimated using measured dielectric parameters. The application of universal Jonscher’s power law plots showed that the Correlation Barrier Hopping(CBH) mechanism is responsible for the conduction in ZnO nanoparticles. The complex electrical modulus and complex impedance spectroscopy proposed the temperature-dependent relaxation processes. The estimated minimum hopping distance (Rmin) and the binding energy (Wm) as a function of temperature are also reported for ZnO nanoparticles.