AC and DC electrical transport studies of (Fe, Co) codoped ZnO nanoparticles

Abstract

The authors have presented microstructural, ac- and dc-electrical properties, and magnetic and optical studies of Zn1-xFex/2Cox/2O (x = 0.1 and 0.2) semiconducting nanoparticles, prepared through low temperature chemical “pyrophoric reaction process.” Structural characterizations confirm the formation of single phase (at a calcination temperature of 300 °C), chemically homogeneous, nanometric sample (∼7 nm). Electrical studies on those samples have been carried out using an ac impedance spectroscopy and dc resistivity technique. Temperature dependent relaxation processes have been investigated by studying complex impedance spectroscopy. The authors have also estimated activation energy from both ac and dc resistivity data of those nanoparticles. Magnetic data clearly reveal the presence of some sort of magnetic behavior, even up to room temperature, in the x = 0.2 sample, whereas for x = 0.1 sample, there in no such magnetic behavior. This feature has been explained through magnetic polaron percolation theory. The authors have also estimated semiconducting band gap of those nanoparticles using recorded absorbance spectra.