Structural, optical, and electrical properties of nanocrystalline CdS1-X CuSX thin films

Thin films of CdS1-xCuSx were prepared using spray pyrolysis chemical technique on a heated glass substrate of 673 K with (300 +/- 50) nm films thickness. The structural, optical, and electrical properties were investigated for pure cadmium sulfide (CdS) and copper sulfide (CuS) doped with concentration level of (3, 6, 9)%. The results of X-Ray diffraction (XRD) showed that the undoped CdS has a polycrystalline structure with a hexagonal crystalline structure, while CdS dope with CuS has two phases, hexagonal and tetrahedral crystalline structure. The optical properties were studied in the range of wavelengths (300-1100) nm and the results showed that the energy gap values reduce from 2.42 to 1.89 eV due to increasing the doping level. To study the Hall effect, the thin films were grown on a crystalline silicon wafer of (111) orientation. The results showed that the pure (CdS) films are n-type with a negative value of Hall coefficient. Increasing the CuS doping concentrations, p-type have been obtained with a positive Hall coefficient. Furthermore, the carrier's concentration conductivity, and mobility increases with increasing the doping level. It was found that the resistivity values for all doped films, decrease with the increasing the doping concentration.