Effect of Sprayed Solution Volume on Structural and Optical Properties of Nickel Oxide Thin Films

Undoped Nickel oxide (NiO) thin films were deposited on 500 degrees C heated glass using spray pyrolysis technique. Effect of volume sprayed solution on structural and optical properties of NiO thin films was studied. Volume amount was ranged in 5 - 30 ml and stepped by 5ml. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and UV-visible spectrophotometer were used to investigate elaborated thin films. XRD results show that the deposited films with volume lower than 10 ml is amorphous and with increasing volume up to 10 ml NiO thin films structure become polycrystalline with cubic structure and (111) as preferential orientation. An increase in diffraction intensity of preferred peak and narrowing in full width at half maximum were observed with sprayed volume increasing, which leads to better crystallinity of NiO thin films. Also it was observed that the grain size increased with increasing volume solution and were averaged in 10 - 28 nm. FT-IR analysis of product confirms the NiO bond formation and the results were compared with previous studies. All films exhibit an average optical transparency between 50 % and 80 % in the visible range and their band gap values are ranged in 3.38 - 3.62 eV.