Synthesis and characterization of chemical bath deposited copper doped lead sulfide thin films

ABSTRACT. The effects of copper concentration on the properties of copper lead sulfide  thin films have been reported. Chemical bath deposition (CBD) method was used to deposit the ternary material on soda-lime substrates. Here, the  films were grown using copper(II) chloride, lead nitrate, and thiourea as sources of copper (Cu), lead (Pb) and sulfur (S), respectively. The grown films were examined using X-ray diffractometer (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy, UV-spectrophotometer and four-point (4P) probes. XRD measurements revealed a polycrystalline material with strong adherent to the substrates. SEM readings indicated various grain-like crystalline morphologies with different sizes that change with copper concentrations. The EDX studies revealed that the deposited material consist of copper, lead and sulfur in various compositions. The transmittance was high in the near infrared regions of the electromagnetic radiation and, also decreases with copper concentrations. The band gap (Eg) varies from 2.05 to 2.50 eV with increase in copper concentrations. The study shows that CBD is an excellent method in depositing good quality films for device applications.   KEY WORDS: Thin films, Substrates, Copper lead sulfide, Deposition, Optical properties Bull. Chem. Soc. Ethiop. 2023, 37(5), 1237-1251.                                                  DOI: https://dx.doi.org/10.4314/bcse.v37i5.15