Electrical Impedance Studies of Iron-Doped ZnO nanostructures

Undoped and iron-doped (5%, 10%, and 15%) zinc oxide (Fe-ZnO) nanostructures were synthesized via a hydrothermal precipitation method. Structural properties of Fe-ZnO were studied by means of X-ray diffraction spectroscopy (XRD), Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM). XRD studies showed the existence of wurtzite ZnO structure in all Fe-ZnO samples. SEM and TEM studies of Fe-ZnO revealed changes in from nano particles to rod shape when the temperature of the precipitation bath was increased from 70 C to 90 C. Electrical transport properties of Fe-ZnO were analyzed by Cole-Cole plot using impedance spectroscopy from 70C to 90 C and were modeled by equivalent RC circuit. The cole-cole spectrum reveals that the resistance of doped sample decreased 70 C to 80C as the morphology changes from nanoparticle to nanorods. From 80 C – 90 C, the electrical resistance of Fe-ZnO nanorod structure increased from 4500 Ω to 5500 Ω. We will discuss the implications of these results based on a transport model.