Comparative study of PbS thin films growth by two different formulations using chemical bath deposition

PbS thin films were obtained using the chemical bath deposition (CBD) technique at 60° C. In this paper were compared two formulations: the standard and a new one. The main result of this work is to report the new chemical formulation to build the PbS thin films, where polyethyleneimine has been used as a complexing agent. With a reaction time of 7.5 minutes we obtain a thickness of 120 nm measured with a profilometer. The structural studies, using X-ray diffraction, show that the thin film is polycrystalline and strongly oriented on the (1,1,1) plane of a cubic structure, while the thin film for the traditional formulation has a preference orientation on the (2,0,0) plane. Morphology by atomic force microscopy depicts a better flatness for the new formulation than with the traditional one. Scanning electron microscopy shows clearly in images the consistency with X-ray diffraction. Also, the optical absorption and transmission for both materials are described as a comparative in the UV-vis region. Finally to reinforce this characterization of the material, to a basic science level, XPS spectra were obtained where we can be observe only those chemical element peaks expected.