Studies on the structural, morphological and optoelectrical properties of spray deposited CdS:Pb thin films

Abstract

Undoped and Pb-doped CdS (CdS:Pb) thin films were prepared on glass substrates by a spray technique using a perfume atomizer. The effects of Pb doping on the structural, morphological and optoelectrical properties of CdS thin films were studied. All of the films are polycrystalline in nature exhibiting hexagonal crystal structure. Crystallite size estimated from the Scherrer formula increased from 18.42 nm to 34.76 nm with increases in Pb doping concentration. The expansion of lattice parameters experienced with Pb doping might be due to the larger ionic radius of Pb²⁺ ions compared to that of the host Cd²⁺ ions. Increased optical transparency is observed for the doped films and the optical band gap experienced band bowing with increase in Pb doping concentration. Electrical resistivity values of the films were found to be on the order of 10¹ Ω cm. From the obtained results, it is observed that the CdS thin film coated with 6 wt.% Pb doping concentration exhibit better structural, morphological, optical and electrical properties.