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It was revealed that, according to the analysis by the half-width of the X-ray lines of reflection planes (200) and (600), the sizes of subgrains in the lead selenide nanolayer ~70 nm thick made up 30-45 nm. Disorientation between the subgrains of the order of the ten thousandth of a minute and the deformation (strain) in the layer was determined by the mismatch between the layer and the substrate. It is shown that the forbidden gap width Eg of the same PbSe nanolayer determined by analyzing the optical transmission spectra by two types of straightening f (hν) and (hν)2=f (hν) coincided and made up 0.445 eV, which exceeded Eg of the unstrained PbSe layer by 0.16 eV. The total contribution of quantum effects at the given subgrain sizes and degeneracy of current carriers is less than 0.03 eV, and generally the change in the forbidden gap width was associated with deformation. Key words: dispersion, deformation, disorientation between subgrains, optical transmission, forbidden gap width.

The article deals with the modified method of "hot-wall" beam epitaxy for obtaining the strained lead selenide nanolayers over a wide range of growth rates and controlling their thickness. With detection of the two-stage growth of the layers, the layers with high deformationstangential lattice constants, and hence with high "negative" pressure were formed. Observations of the shift of the optical spectrum in strained layers and the possibility of deep compensation of the concentration of current carriers when doping the layers with impurities with variable valence turned out to be interesting as well. Under high deformations, the texture of a tetragonal phase is formed. There appears a new level in the conduction band and hence additional absorption in the optical spectrum. The given specific features were first discovered in the physics and technology of IV-VI semiconductors, and they open new opportunities of using these semiconductors in IR optoelectronics.

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