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

The initial incorporation processes of bismuth on GaAs(001)-c(4 x 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 x 4)alpha 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. (c) 2013 Elsevier B.V. All rights reserved.