Investigation of the Temperature on the Thin Layers of Cobalt Oxide Produced by the Spray Pyrolysis Method Using a Solar Oven

Thin films of cobalt oxide (Co3O4) were prepared on glass substrates by the spray pyrolysis method using a solar concentrator (oven) manufactured in our laboratory. We used different processing temperatures (300° C, 350° C and 400° C). The structural, optical and electrical properties of the different samples were analyzed by X-ray diffraction (XRD), UV-Visible spectroscopy and the Hall effect measurement system. X-ray diffraction observations revealed that cubic crystals are created in all films produced, and the film structure is that of a single phase created with preferential orientation along the (311) axis in films at low temperatures, and the axis (111) for high temperatures. The grain sizes of our products vary between (22.62nm and 66.19nm), depending on the processing temperature. The optical band gap of the crystals obtained was measured. The results of the optical forbidden bands of the crystals obtained, indicated two bands of the values for each element (Eg1 and Eg2). We observed that the values of the effective optical forbidden bands increase by 2.547eV and 3.0731eV with the increase in the production temperature., In addition the film produced experiences a decrease in the Urbach parameters which vary between 162.20meV and 360.81meV depending on the increase in production temperatures. Finally, the films produced have electrical conductivity values of (1.090 [(Ω.cm)⁻¹] to 1.853 [(Ω.cm)⁻¹] and electrical resistivity values of 1.431 (Ω.cm) at 1.853 (Ω.cm), depending on the variation in the production temperature.