Surface structure of bismuth terminated GaAs surfaces grown with molecular beam epitaxy

• Published in: Surface science 2012-08, Vol.606 (15-16), p.1203-1207
• Main Authors: Duzik, Adam, Thomas, John C., Millunchick, Joanna M., Lång, J., Punkkinen, M.P.J., Laukkanen, P.
• Format: Article
• Language: English
• Subjects: Atomic beam spectroscopy; Bismuth; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Disorders; Exact sciences and technology; Gallium arsenide; Gallium arsenides; Micrometers; Molecular beam epitaxy; Morphology; Physics; Reconstruction; Scanning tunneling microscopy; Surface reconstruction; Surface structure; Surfactant
• ISSN: 0039-6028; 1879-2758
• DOI: 10.1016/j.susc.2012.03.021

We determine the atomic surface structure of the Bi-terminated GaAs(001) (1×3) reconstruction for the first time using scanning probe microscopies, photoemission spectroscopy, and ab initio calculations. The proposed kinked-dimer (4×3) model is consistent with experimental characterization and can accommodate a variety of species configurations due to an availability of low-energy sites for Bi substitution, accounting for the significant observed local disorder. In addition, experiments show that stability of this reconstruction coincides with a dramatic change in surface step morphology, giving rise to strong up/down step interaction and a counterintuitive smoothing effect on the micrometer length scale. ► Deposited 2.4ML (or 6ML with As4) of Bi onto GaAs(001) β2(2×4) surface. ► Reflective high-energy electron diffraction shows (1×3) and (4×3) patterns. ► Scanning tunneling microscopy (STM) reveals β(4×3) reconstruction. ► High number of up-down step edge pairs in STM suggest origin of Bi smoothing effect. ► Synchrotron photoemission spectra indicate α(4×3) and γ(4×3) reconstructions.