First principles investigation of chemisorption of moderately heavy atoms on semiconductor surfaces—bromine on silicon

Publisher Website
Google Scholar
Abstract
Self‐consistent field Hartree–Fock cluster investigations have been carried out for bromine atoms chemisorbed on Si (111) surface using 5, 14, and 27 atom clusters. For the first two clusters, both all‐electron and pseudopotential procedures have been used and the total energy curves as a function of adatom position have been found to compare very well. The third cluster has been studied by the pseudopotential procedure alone. For the five‐atom cluster which corresponds to the SiH3Br molecule, the Si–Br bond distance and 79Br quadrupole coupling constant (e2qQ) are obtained as 2.20 Å and 355.4 MHz, respectively, in very good agreement with the experimental values from microwave measurements of 2.21 Å and 346 MHz. For the surface chemisorbed system, we have studied the location of the bromine atom, the local density of states (LDOS), the frequencies and amplitudes of the Si–Br vibrations and the 79Br quadrupole coupling constant. The calculated Si–Br bond distance of 2.23 Å agrees very well with two experimental values of (2.22±0.01) and (2.17±0.04) Å available in the literature. For the vibrational amplitude, satisfactory agreement is found with the available result for Br on germaniumsurface. It is hoped that experimental data will become available in the future to test our predictions for the other properties. In particular, it would be desirable to have UPS data to compare with the interesting trends found in the LDOS curves in going from fluorine to chlorine to bromine and quadrupole interaction data to verify the significant decrease in e2qQ in going from the molecule to the surface‐adsorbed system.

This publication has 0 references indexed in Scilit: