The effect of sulfur precursor on the morphology, properties and formation mechanism of chemical bath deposited Pb1+xS thin solid films

• Published in: Materials chemistry and physics 2023-09, Vol.305, p.127936, Article 127936
• Main Authors: Kozhevnikova, N.S., Maskaeva, L.N., Enyashin, A.N., Uritskaya, A.A., Pozdin, A.V., Voronin, V.I., Selyanin, I.O., Mostovshchikova, E.V., Markov, V.F.
• Format: Article
• Language: English
• Subjects: Chemical bath deposition; DFT calculations; Morphology; Optical properties; PbS; Thin solid film
• ISSN: 0254-0584
• DOI: 10.1016/j.matchemphys.2023.127936

Pb1+хS thin films of 190–360 nm thickness have been synthesized on glass substrates by chemical bath deposition from aqueous solutions using different thioamides (thiourea, N-allylthiourea, thioacetamide) as sulfur precursors. The obtained films are polycrystalline semiconductors with n-type conductivity. The effect of the sulfur origin on the crystalline structure, morphology and formation mechanism of Pb1+хS thin films is analyzed. The formal rate constants of Pb1+хS formation reactions are determined. Quantum-chemical calculations approve that a lead superstoichiometry in the obtained films may be attributed to types of point defects: atomic vacancies in the sulfur sublattice and the lead doping the sulfur sublattice. A correlation is established between the amount of lead excess and the optical band gap of Pb1+хS: the greater the excess of lead is, the wider the band gap is. The fractal analysis of Pb1+хS thin films evidences the film growth obeying model of a cluster-by-cluster association in three-dimensional space. •Pb1+хS thin films were obtained from aqueous solutions using different thioamides.•All synthesized films are Pb-rich with n-type conductivity.•Pb1+хS film formation is described as heterogeneous autocatalytic process.•Hydrolytic decomposition of thioamide determines the rate of the Pb1+хS formation.•By varying the thioamide type the control of Pb1+хS film morphology is possible.