Sb dissociative surface coverage model for incorporation of antimony in GaAsSb layers grown on GaAs (0 0 1) substrates

• Published in: Journal of crystal growth 2019-11, Vol.526, p.125231, Article 125231
• Main Authors: Zhang, Z., Ghosh, K., Faleev, N.N., Wang, H., Honsberg, C.B., Reece, P., Bremner, S.P.
• Format: Article
• Language: English
• Subjects: A1. Growth models; A3. Molecular beam epitaxy; B1. Antimonides; B2. Semiconducting III-V materials
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2019.125231

•Surface segregated layer of Antimony included in GaAsSb growth model.•Langmuir isotherm surface coverage expression corrected.•Key desorption parameters for Sb on GaAs obtained experimentally.•Good prediction for GaAsSb composition seen for growth condition variations. A Sb dissociative surface coverage model for the incorporation of antimony in GaAsSb layers, has been used to analyze and predict the composition of GaAsSb layers grown on GaAs substrates. The surface coverage model is based on adatoms behaving according to a modified Langmuir isotherm when on the growth surface. After obtaining key parameters for describing the desorption of Sb atoms from a GaAs surface the model was used to fit the composition variation with changing Sb flux of pseudomorphic GaAsSb layers grown by molecular beam epitaxy on GaAs(0 0 1) substrates at growth temperatures of 470 °C, 500 °C and 530 °C. The set of parameters that provided the best fit to the data for all of these temperatures was then used to predict the incorporation rate as a function of As flux and growth rate with good agreement showing the validity of the Sb dissociative surface coverage model.