Role of indium doping on structural and electrical properties of ZnO nanoparticles prepared by sol-gel method

In this work, we report the synthesis of undoped ZnO and In-doped ZnO nanoparticles by sol-gel method from 0 to 5 wt% of In amount. The effect of indium incorporation on structural and electrical properties of these samples was investigated. X-ray diffraction analysis confirms the formation of undoped ZnO and In-doped ZnO nanopowders with a hexagonal wurtzite crystalline structure and the average crystallite size varies between 31 and 55 nm. The morphological study shows that the shape of the crystallites is hexagonal and it changes into cylindrical prismatic after doping. Further, the study of electrical response was carried out by impedance spectroscopy. The electrical properties of these samples are dependent on temperature and frequency. We find that the conductivity increases with increasing In dopant. It has been found that the highest conductivity corresponds to the concentration 3% of indium content. Concerning the complex impedance analysis, the equivalent circuit of grain consists of resistance and constant phase element in parallel. These results contribute to various technological applications.