Fabrication of cu-doped nanostructured znxcd1-X S films as window layers for solar cell applications

In this research, (ZnxCd1-xS and ZnxCd1-xS: 0.3 Cu) films (x = 0, 0.3, 0.5, 0.7,1) were prepared using the chemical spray pyrolysis technique (CSPT) on glass substrates at a temperature of 325 ºC. The X-ray diffraction (XRD) results indicated that all prepared films have a polycrystalline structure. Increasing the value of "x" from 0.1 to 0.9, the intensity decreases with a slight shift towards higher angles due to the incorporation of Zn ions into the CdS lattice. The copper doping process led to a decrease in intensity and an increase in (FWHM), which led to a decrease in crystal size. The results of atomic force microscopy (AFM) images of (ZnxCd1-xS: 0.3 Cu) films showed that the prepared films had good homogeneity, the film was well distributed on the substrate, and all films were free of cracks. The grain size decreased with increasing value of (x). Scanning microscope images show that the particles have a spherical shape with a nanoparticle size and are almost similar and well distributed on the surface of the substrate. The particle size decreases with increasing value of (x). EDX results confirmed the presence of cadmium (Cd), zinc (Zn), sulfur (S), and copper (Cu). From the results of the optical properties, we note that the transmittance increases with the increase in the value of (x) due to the increase in the percentage of zinc (Zn) content in the prepared solution, which leads to a decrease in the thickness of the films and thus an increase in the transparency of the films. The optical energy gap increases with the increased concentration of zinc in the prepared solution. Electrical properties results indicated that all films exhibited negative (n-type) conductivity and that the prepared films possess two activation energies, and the higher the concentration of the zinc solution, the greater the resistance and the lower the conductivity in the prepared films. Based on the aforementioned results, solar cells can utilize the prepared films as windows.