Effect of Substrate Temperature on Properties of Nickel Oxide (NiO) Thin Films by Spray Pyrolysis

NiO thin films were deposited on a glass substrate and investigated for the physical properties optimized through substrate temperature (350–390°C) using a spray pyrolysis technique. The effect of substrate temperature on deposited NiO thin film was studied by thermogravimetric analysis and differential thermal analysis, X-diffraction (XRD), field electron scanning electron microscopy, optical absorption and electrical measurement techniques. XRD analysis indicates that NiO thin films are of a polycrystalline cubic structure. Optical properties are calculated with help of transmittance and absorbance data in the wavelength range between 200 nm and 900 nm. The optical band gap energy values increased from 3.1 eV to 4.0 eV with substrate temperature. Further, the extinction coefficient, refractive index, and real and imaginary parts of dielectric constant and optical conductivities of NiO thin films were calculated. The electrical resistivity measurement shows conductivity of the NiO thin film increased with increase in substrate temperature.