Optical, structural and electrical properties of ZnO - Mg thin films prepared by sol-gel method

Abstract

In this research, thin films of ZnO doped Mg at 0.65 M, synthesized by the sol-gel method, and deposited on quartz substrates by the spin-coating method were evaluated. The effect of the annealing temperature (400, 500 and 600 °C) and the molar percentage of the dopant (2, 4, 6 and 8%) on the electrical and morphological properties were determined. It was found that, the thin films of ZnO show the highest electrical conductivity and large grain size at doping of 2% Mg with an annealing temperature of 600 °C, with values of 8.55x10-7Ω-1cm-1 and 38.56 nm respectively. Also, the lowest electrical conductivity and the smallest grain size is given to a doping of 8% Mg with an annealing temperature of 400 °C, with values of 1.48x10-7 Ω-1cm-1 and 14.13 nm; so, the grain size grows with the increase of the temperature; but it decreases as the molar concentration of Mg increases. The grain size was determined by the Scherrer equation on the X-ray diffraction peaks (XRD). The results showed that the thin films of ZnO doped with Mg have a wurtzite hexagonal structure with a preferential orientation to the plane (002).