Concentration Dependent Structural, Morphological, Spectral, Optical and Electrical Properties of Spray Pyrolyzed NiO thin films

Nickel oxide (NiO) thin films were prepared by spray pyrolysis technique using a solution of nickel (II) chloride hexahydrate (NiCl₂.6H₂O) and distilled water on glass substrates. The substrate temperature during deposition was maintained at 450 ^∘C. The effect of solution concentration on the structural, morphological, elemental, spectral, optical and electrical properties of the NiO films were studied for different concentrations from 0.1 M to 0.3 M by XRD, SEM, EDX, FTIR, UV-vis-NIR spectrophotometer, Hot probe and Hall effect measurement system. The XRD study reveals that the NiO films are polycrystalline in nature with cubic structure. Also, the crystallite size increases with the increase in solution concentration. According to SEM, the increase in grain size clearly shows the effect of solution concentration. The elemental composition of the film was determined by EDX. FTIR study shows the presence of chemical identification. The optical band gap decreases while the absorption increases with the increase in solution concentration. The electrical study shows that all the NiO films are p-type. However, resistivity, carrier concentration and carrier mobility of the NiO films depend on the solution concentration.