Preparation and Study of the Effect of Cobalt and Magnesium on the Structural and Optical Properties of Cadmium Sulfide Compound

The compound cadmium, magnesium and cobalt sulfide was prepared in liquid form at the concentration of each of them respectively (0.1, 0.5 and 0.5) M. Where all the films were prepared CdS, CdS:Mg , CdS:CO , CdS:Mg:CO using spray pyrolysis thermochemical technique. Solutions were deposited on glass bases at a fixed settling temperature of 450 °C and at a fixed spray rate of 15 sprays within 15 minutes. The thickness of the films that were prepared was 150 nm. Results showed that they are polycrystalline, and their grain size decreases when cobalt and magnesium are added to the cadmium sulfide compound, while the width of the curve increases with atomic FHWM because it is an inverse relationship between the grain size and full width at half maximum (FHWM). Also, the results showed that all the prepared films have high surface homogeneity and are free of cracks and needle holes that induce films during their preparation. In addition, results scanning electron microscope showed that the particle size decreases when cobalt and magnesium are added to the cadmium sulfide compound, and this result is identical to the results of X-ray diffraction. The optical properties of all the prepared films were studied, where the absorbance was measured as a function of wavelength and the absorption coefficient was calculated from the absorbance spectrum, as well as the energy gap values were calculated. The results showed that the absorbance spectrum behaves visually similar to all the prepared films and that the absorbance values decrease when cobalt and magnesium are added to the cadmium sulfide compound. While the results of the absorption coefficient showed that it behaves similar to the absorption spectrum due to the direct relationship between them, in addition to that, the values of the absorption coefficient showed that it is greater than (10000/cm), and this means that direct electronic transitions occur. By knowing the absorption coefficient, the values of the direct energy gap were calculated, and it was shown that its values increase when cobalt and magnesium are added to the cadmium sulfide compound.