Optoelectronic properties of Cl and F doped CdS thin films grown by chemical bath deposition

CdS:Cl and CdS:F thin films were grown on glass substrates at 70 °C by chemical bath deposition. NH4Cl and NH4F (NH4X) were employed as chlorine and fluorine sources, respectively. The structural, optical, electrical and topography properties were analyzed as a function of NH4X concentration. According to structural characterization, samples grew with a cubic structure, being unaltered by the incorporation of Cl or F impurities. However, crystalline quality can be improved depending on the dopant type and concentration. Optical results revealed that Cl and F doping has noticeable effects on the optical properties by reducing the CdS bandgap for both impurities from 2.45 to 2.31 eV (Cl) and 2.29 eV (F). Electrical resistivity for the films was in the order of kΩcm and it was not substantially affected by the incorporation of Cl and F atoms into the CdS lattice.