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.

Adsorption and dynamics of group IV, V atoms and molecular oxygen on semiconductor group IV (0 0 1) surfaces

“…The MM (molecular mechanic) portion of the calcul ation was completely optimized using MM3 parameters [77]. The NOON for the LUMO of the M/Si(0 0 1) system only contains <0.1 (see table 2), indicating that the metal (M-As, Sb, Bi) atoms nearly completely saturate the dangling bonds of the Si(0 0 1) surface, in agreement with experimental observations [2,[78][79][80][81][82][83][84][85][86][87]. The π and π* electronic states near the Fermi level vanish upon the adsorption of As, Sb or Bi dimers on Si(0 0 1).…”