Excitation spectra of Bi/Si(001) interfaces

Abstract

Present article deals with the theoretical and experimental investigation of optical properties of Bi/Si(001) interfaces in a wide spectral range (1–4 eV). Theoretical excitation spectra of vicinal Si(001) surface, Bi/Si(001)–0.5 monolayer and Bi/Si(001)–1 monolayer interfaces are calculated by time‐dependent density functional theory with the hybrid Becke and Lee, Yang and Parr pseudopotential. Calculations and experimental studies of the absorption spectrum of the samples revealed the blue shift of the optical absorption edge with increasing of the bismuth covering degree. Features of the experimentally obtained reflectance anisotropy spectra (RAS) and surface differential reflectance spectra (SDRS) concerned with changing of the silicon surface reconstruction from 2 × 1 to 1 × 1 with the increasing of the bismuth covering degree from 0.5 to 1 monolayer. It is shown that the correlation between the theoretically calculated and experimental data makes it possible to identify the electronic transitions in the surface region.