Abstract
The successive ionic layer adsorption and reaction (SILAR) technique has been used to prepare silver and cobalt dual doped CdS thin films with a total doping percentage of 10%. Structural and optical properties were investigated for all prepared thin films. X-ray diffraction (XRD) of CdS thin films explored the amorphous structure of all samples. Transmission electron microscope (TEM) photos presented that CdS thin films were quantum dots (QDs) with size below 10 nm. The doping process improved the band gap energy of CdS thin films which were in the range (2.28–2.44 eV) in the comparison of pure CdS (2.55 eV). The red-shift in band gap values of dual doped films, which was observed, can be candidate material in solar cell application. The width of the Urbach tail energy of doped thin films was found higher than pure CdS due to a high disorder degree in the forbidden band gap. Photoluminescence spectra confirmed that the synthesized CdS were QDs with the band edge emission at 406 nm. This suggests the combination between CdS nano-size features and their improved optical properties.
•Ag and Co dual doped CdS thin films were prepared via SILAR method.•The synthesized CdS were quantum dots.•The red shift of band gaps of dual doped thin films were obtained.•Urbach energy of doped thin films were obtained higher than pure CdS.•Optical properties of doped CdS thin films were improved.