Structural and Optical Properties of Nanocrystalline Nickel Oxide Thin Film by Spray Pyrolysis Technique

It is necessary to study the optical properties of thin films to fabricate optoelectronic and interference devices. One of the methods in thin film preparation is the spray pyrolysis technique, which involves many technical aspects for the preparation of uniform coating. In the present study, Nickel Oxide (NiO) thin film is prepared by spray pyrolysis technique. NiO thin film was deposited using 0.5M aqueous solution of nickel chloride onto ultrasonically cleaned glass substrate at Tsub = 350C. The film is more homogeneous and there is no pinhole. The structural and optical properties of the sample were examined by X-Ray Diffraction (XRD), UV-Visible and Photoluminescence (PL) spectral analysis. XRD study revealed that the film exhibited (1 1 1) orientation with cubic structure. The thickness of NiO film was 0.16 μm and the calculated grain size was 51 nm. UV – Visible spectral study of the film exhibit high optical transmittance in the visible region and the film possess direct band gap value of 3.5 eV. The reflectance and refractive index are also calculated from the optical measurements. The room temperature excitation PL spectrum of NiO thin film shows a strong dominant peak at 362 nm. These results suggest that this NiO thin film can be used as an antireflection coating in solar cells.