Dielectric Properties and Conductivity of (ZnO/CdO) Mixed Oxide Nanocomposite

Abstract

Nanoparticles of zinc oxide and zinc-cadmium oxide were prepared from their respective metal acetates, and ammonium carbonate using ethylenediaminetetraacetic acid (EDTA) as capping agent followed by decomposition. The heat treatment of the precursor powders at their decomposition temperature and beyond, results in the evolution of heat from the combustion of carbonaceous material. This facilitates the reaction among the constituent metal ions and the desired oxide phase is formed at low temperature. The particle size was determined by X-ray diffraction and the diffractogram was compared with JCPDS data to identify the crystallographic phase. The shift in the ‘d’ value and elastic micro strain was calculated.The FTIR studies were used to confirm the formation of metal oxide. The absorption spectra of samples were recorded and band gap calculated. It is observed that band gap tuning of ZnO is possible by addition of cadmium. The effect of temperature and frequency on the dielectric behaviour and ac conductivity of the samples were studied. The dielectric permittivity is evaluated from the observed values of capacitance in the range of 1 kHz to 10 MHz, in the temperature range 300 K to 403 K. It is seen that with the decrease in frequency, the dielectric constant increases much more obviously than that in conventional materials due to space charge polarisation and rotation direction polarization. Due to the incorporation of cadmium both capacitance and conductivity increased by an order of 10³. Cole-Cole plots are drawn and dispersion parameters are calculated

Keywords:

• Metal oxide nano particles
• mixed oxide
• band gap
• dielectric constant
• conductivity
• dispersion parameters

Acknowledgments

The authors also acknowledge STIC cochin for SEM, TGA analysis, NIIST, Trivandrum for XRD measurements and SAIF BOMBAY for the TEM results.

Funding

The first author acknowledges financial assistance from UGC.