The effect of temperature on nickel oxide thin films produced by spray pyrolysis method using a solar oven

Nickel oxide (NiO) thin films were deposited on glass substrates using spray pyrolysis to study the effect of fabrication temperature on their structural, optical, and electrical properties. Processing temperatures of 350°C, 450°C, and 550°C were used. X-ray diffraction (XRD) revealed cubic crystals with a single-phase structure oriented along the (220) axis. Grain sizes ranged from 8.2 nm to 64.52 nm. Optical band gaps increased from 3.37 eV to 3.57 eV with higher temperatures, while Urbach energy decreased from 362.12 meV to 280.32 meV. Electrical resistivity varied from 316.22 Ω.cm to 1500.14 Ω.cm, and hole concentration from 5.645x1018 cm-3 to 9.987x1018 cm3.