Sol-Gel Synthesis of Nickel Oxide Thin Films

In work, highly transparent conductive NiO thin films have been deposited on glass substrate by Sol gel spin coating method. The influence of annealing temperature on structural, optical and electrical properties was investigated. The DRX analyses indicated that ZnO films have polycrystalline nature and a cubic NiO phase with (111) and (200) preferential orientation corresponding to NiO films were observed at high temperature. The optimal values of the average crystallite size of the ZnO films under consideration are observed begin of 550 °C of annealing temperature. The increase of the crystallite size has been indicated by the enhancement of the crystallinity under a-axis orientation of NiO. All annealed films exhibit an average optical transparency about 80 %, in the visible range. The shift of optical transmittance towards higher wavelength can be showed by the increase of band gap energy from 3,536 to 3.854 eV with increasing of annealing temperature of 450 to 600 °C. The observed Urbach energy of ZnO thin films decreases from 339,311to 180.756 meV. The good electrical conductivity was found at 550 °C.