The effect of the substrate material on the structure, topology, composition, optical and mechanical properties of chemically deposited PBS films

The article presents the results of comprehensive studies of the influence of the substrate material on the structure, composition, topology and optical properties of chemically deposited lead sulfide films using X-ray diffraction, electron and atomic force microscopy methods, with an estimation of the mechanical stresses arising in the volume of the films and at the film-substrate interface. It is found that the formation of the films on fused quartz and synthetic sapphire substrates occurs from crystallites with a predominant (111) crystallographic orientation, and on photo glass and microscope slide substrates - from crystallites with both (111) and (220) orientations. The effect of preliminary etching of substrates in HF acid on the surface topology and features of nucleation of the PbS films is discussed. It is concluded that the surface relief of lead sulfide films does not repeat the relief of the substrates. Using fractal formalism, it is shown that the formation of the PbS films on all studied substrates is described by a model of particle association of the cluster-particle type in three-dimensional space. A correlation is revealed between the number of nanoparticles in the PbS layer and the band gap of the material. An increase in the magnitude of compressive stresses at the film-substrate interface is found within the range from -53.9 to -318.6 kN/m$^2$ in the series slide-photo glass-sapphire-quartz.