Spin coating method deposited nickel oxide thin films with various film thicknesses

The objective of this research is to study the influence of film thickness on the optical and electrical properties of prepared NiO thin films. Nickel oxide thin films have been prepared on the glass substrates by a spin coating technique using nickel nitrate hexahydrate (Ni(NO3)(2).6H(2)O) as a source of materials. The coating process was repeated 11, 13, 15, and 17 layer times to obtain a good NiO thin film. The optical and electrical characterizations were observed to be dependent on each film thickness. The smaller layers have a high optical transmission (over 88%) in the visible range. The bandgap energy was found to be in the range of 3.94-4.06 eV depending on the film thickness. The lowest value of Urbach energy was 0.182 eV. The electrical measurements are investigated by the four-point method; the results show that good electrical conductivity was found for the sample with a thickness around 171 nm.