Cobalt-Doped Chemically Deposited Lead-Sulfide Films

This work continues the study on the doping of chemically deposited PbS(I) layers and discusses the effect of cobalt ions on their morphology and the structural, optical, and photoelectric properties. It is shown using energy-dispersive elemental analysis that cobalt is found in the films at a cobalt-chloride concentration of ≥ 0.04 mol/l in the reaction mixture. The synthesized PbS(I,Co) films retain the B 1 cubic structure (sp. gr. ). A tendency to an increase in the band gap of the PbS(I,Co) films from 0.57 to 0.75 eV with an increase in the nanoparticle content in them from 1 to ~8% during 1.5-h deposition and from 0.57 to 0.68 eV with an increase in the nanoparticle content from 13 to ~28% during 3-h deposition is observed. The concentration dependence of the voltage sensitivity of the PbS(I,Co) films deposited for 1.5 h contains two maxima corresponding to nanoparticle contents of 1 and 4%. During 3-h synthesis, a sharp decrease in the photoresponse with an increase in the nanoparticle content to 13‒28% in the PbS(I,Co) layers is found. It is shown that the photocurrent density decreases with increasing content of nanoparticles in films in the series PbS(Co) → PbS → PbS(I,Co) → PbS(I).