Ab initio-based approach to initial incorporation of Bi on |GaAs(001)-c(4×4)α surface

The initial incorporation processes of bismuth on GaAs(001)-c(4×4) surface are investigated by using our ab initio-based approach taking chemical potentials in the gas phase into account. The calculated surface phase diagrams obtained by comparing the adsorption energy with the gas-phase chemical potential demonstrate that the form of incorporated Bi depends on the growth conditions. The Ga–Bi dimer easily adsorbs on the missing dimer region of the c(4×4)α surface where as the Bi–Bi dimer adsorption occurs after the Ga–As dimer desorption on the surface with a Ga–Bi dimer. These results imply that the adsorption of Bi–Bi dimer accompanied with Ga–As dimer desorption is crucial for the growth process of GaAsBi on GaAs(001) substrates.

► The incorporation process of Bi on GaAs(001) surface is theoretically investigated.
► Bi is incorporated on the GaAs(001) surface under growth conditions as a Ga–Bi dimer.
► A Ga–As dimer desorbs from the surface with the Ga–Bi dimer adsorption.
► Bi atoms are incorporated as a Bi–Bi dimer after the Ga–As dimer desorption.
► The results suggest that the behavior of a Bi–Bi dimer and the Ga–As dimer are important.