Determining the GaSb/GaAs-(2 x 8) reconstruction

SURFACE SCIENCE

卷:603

Article

Bickel, Jessica E.¹  Modine, Normand A.²  Millunchick, Joanna Mirecki¹ 

[1] Univ Michigan, Dept Mat Sci & Engn, Ann Arbor, MI 48109 USA

[2] Sandia Natl Labs, Ctr Integrated Nanotechnol, Albuquerque, NM 87185 USA

关键词: Surface relaxation and reconstruction;    Density functional calculations;    Molecular beam epitaxy;   

DOI  :  10.1016/j.susc.2009.07.044

来源: Elsevier

【 摘 要 】

Highly strained thin layers of GaSb/GaAs possess a (2 x 4) reconstruction at low Sb overpressures, and a (2 x 8) reconstruction at high Sb overpressures. While the atomic details of the Sb/GaAs-(2 x 4) are well known, the details of the (2 x 8) are not understood. In this paper, we use density functional theory to analyze possible (2 x 8) structures. Comparing scanning tunneling microscope images from both simulation and experiment and examining the relative energies of possible (2 x 8) structures, we show the alpha(2 x 8) and beta(2 x 8) are the thermodynamically stable surface reconstructions for high Sb content films strained to the GaAs lattice parameter. The alpha and beta(2 x 8) reconstructions are related to the GaAs-alpha 2(2 x 4) and GaAs-beta 2(2 x 4) through the addition of 2 cations and 8 anions into the trench between adjacent (2 x 4) unit cells. (C) 2009 Elsevier B.V. All rights reserved.

【 授权许可】

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