Synthesis and characterization of nickel oxide thin films by spray pyrolysis method: Effect of nickel source nature

Nickel oxide (NiO) material had been reported as one interesting candidate for transparent conductive oxides (TCO) applications, given their specific properties. In this work, we have synthesized un-doped nickel oxide (NiO) thin films by using the spray pyrolysis method deposited on heated glass substrates at 500°C. The effect of the Nickel source on the optical and electrical properties of the prepared films had been reported. We have used two sources of nickel: nickel nitrate (Ni (NO₃)₂.6H₂O) and nickel Chloride (NiCl₂.6H₂O). The characterization techniques such as UV-visible spectroscopy and the two-point probe technique were used to investigate the prepared NiO thin films. The optical analyses show that all the samples exhibit averaged optical transparency between 52% and 61% in the visible region. The evalueted optical gap- the energy of the NiO thin films between 3.59 and 3.84eV with the change of nickel source. Refractive index and extinction coefficient values were decreased with a variation of nickel source. From Electrical measurement, it was observed that the minimum resistivity of the NiO films are 0.106 Ω from films prepared with nickel nitrate source.