Transparent nanostructured Co doped NiO thin films deposited by sol‒gel technique

Abstract

In this work, the effect of annealing temperature (540, 560, 580 and 600 °C) on synthesis of Co doped NiO thin films were investigated. Co doped NiO thin films were deposited by spin coating method with molarity of 0.8 mol.l−1 at room temperature. The XRD analyses showed that the NiO films have a cubic structure with high crystallite size of in Co doped NiO thin film is 82.57 nm of (200) plane was obtained at 580 °C. This is to improvement the structure crystallinity. The optical transmission showed that the band gap energy was found increases from 3.2265 to 3.8382 eV at 600 °C. At high annealing temperature, the Co doped NiO thin films having a less disorder and fewer defects with minimum Urbach energy was 266 meV at 600 °C. The calculate refractive indices were found in qualitative agreement to the values derived from Reddy, Kumar and Ravindra models. P‒type semiconducting Co doped NiO thin films’ having a maximum value of the electrical conductivity was found at 580 °C. The annealing temperature at 580 °C the Co doped NiO thin films have a good crystallinity, optical and electrical conductivity.