Influence of copper concentrations on the morphological and optical characteristics of iron sulphide thin films

The development of copper-doped iron sulphide ( \:CuₓFe₁₋ₓS ) thin films was accomplished by the chemical bath deposition (CBD) method. The morphological and optical measurements were done to see if the films may be suitable for optoelectronic applications. The copper-doped iron sulphide material that was formed by changing the concentrations of copper exhibits a micrograph with a variety of irregular and rough grain sizes and shapes. EDX analysis of the deposited films showed that the stoichiometry and the thickness depended on copper concentrations. The linear optical results of the copper-doped iron sulphide films revealed that the band-gap ( \:Eg ) values were decreased from 2.25 to 1.40 eV by increasing the copper content in the analysed samples. Further, the rise in copper content enhanced the refractive index from 2.25 to 2.66. As the copper concentration was changed, the absorbance of the films decreased. Simultaneously, it was discovered that other optical constants changed as the copper level increased, including an increase in transmittance and reflectance, both of which are critical for optimising the performance of optoelectronic devices. According to the results, these samples can be used as a novel absorber layer in optoelectronic applications, particularly due to their improved optical properties and efficiency at varying copper concentrations.