Study of The Optical Properties of Copper Oxide Thin Films Prepared by Chemical Spray Pyrolysis Technique

In this paper, thin films of Copper Oxide (CuO) were deposited on glass substrates using the chemical spray pyrolysis method at different temperatures (300, 350 and 400)°C under a pressure of 2 bar. The deposition involved spraying the chemical solution at a rate of 10 sprays, periodic time 10s. The chemical spray pyrolysis system was assembled, prepared, and configured to produce the materials in the form of thin films for this study. The optical properties of these films were investigated by measuring the absorbance and reflectance spectra for wavelengths ranging from )190-1100( nm using a UV-VIS Double Beam Spectrometer. The results indicated that the absorbance varied with wavelength, exhibiting an inverse behavior to transmittance. It started with the highest value at a wavelength of 328 nm, and the absorption spectrum exhibited a systematic decay with increasing wavelength until reaching the lowest value at 910 nm. It was observed that the absorbance spectrum remained constant within the range of 910 to 700 nm. The highest absorbance value was recorded at a temperature of 300°C, while the lowest was at 400°C. This trend was also observed in the optical reflectance. The forbidden energy gap for allowed direct transitions was calculated, and the results showed values ranging from (2.68 to 2.59) eV, decreasing with increasing temperatures. Some optical constants of the prepared films were also calculated, indicating a decrease in the absorption coefficient, extinction coefficient, and refractive index with increasing temperatures on the glass substrates used for deposition.