Electron Energy Characteristics of Two-Dimensional Hydroxysiloxane Structures with Defects of Substitution of Silicon Atoms by Titanium and Zirconium Atoms
A computation scheme based on density functional theory adapted for structures with translational symmetry with full optimization of geometrical parameters is applied to calculate the two-dimensional dielectric (single layer) hydroxysiloxane structures as an ideal composition as well as with defects of substitution of silicon atoms by titanium and zirconium atoms. The dependence of the electron energy spectrum and position of the optical absorption curves both on the type of atoms-substituents and their concentration is investigated. It is shown that at the substitution, besides boundaries shifts of energy bands and their widths, states with energies inside the region of forbidden energies corresponding to defect-free structure occur. Optical transitions involving these states appear in the absorption spectrum or in the form of separated bands, or of bands merging with the ones corresponding to transitions from 2p-top of valence band into the conduction band in dependence on the type of substituting atoms.