Concentration of Spraying Solution Effect on the Structural, Morphological and Optical Properties of NiO Thin Films

Abstract

In the present study nickel oxide NiO thin films of thickness ranging about 250-350 nm which were prepared on glass substrates by using chemical spray pyrolysis as a simple and low cost method. The impact of thickness and aqueous solution molarity concentration on the crystal structure and optical characteristics were investigated. The results showed that the deposited films is homogenous and have a good adherent to the glass substrates. The crystal structure results showed that all films have polycrystalline in nature, of rock salt phase, and the preferential orientation is an along (111) plane. The diffraction intensity was increased with the increase in spray solution concentration, leading to the enhancement of the crystallinity and an increase in the crystallite size from 9.7 nm to 28.5 nm and reducing the dislocation density from (104.3 to 12.2) × 1016 line/m2. While the results of AFM results show that the grain size (D) enlarges with increasing molarities concentration. Transmittance spectra confirm that the optical transmittance is of the direct allowed type, while the value of transparency ranged from moderate to weak value and decrease when the spray solution molar concentration and film thickness increases. Whereas the forbidden energy gap was decremented with the increment of molarity concentration of spray solution and film thickness from 3.85 to 3.15 eV.