Orientation-dependent phase separation of GaAsSb epilayers grown by gas-source molecular-beam epitaxy

• Published in: Thin solid films Vol. 520; no. 13; pp. 4486 - 4492
• Main Authors: Chen, Yi-Ren, Chou, Li-Chang, Yang, Ying-Jay, Lin, Hao-Hsiung
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 30.04.2012; Elsevier
• Subjects: Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; GaAsSb; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Molecular beam epitaxy; Molecular, atomic, ion, and chemical beam epitaxy; Other semiconductors; Phase separation; Physics; Regular solution model; Semiconducting III–V materials; Specific materials; Molecular beam epitaxy; Regular solution model; GaAsSb; Phase separation; Semiconducting III–V materials; Semiconducting III-V materials; Gallium Antimonides arsenides; Epitaxial layers; Monolayers; GSMBE method; Free energy; III-V semiconductors
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2012.02.024

This work describes a regular solution model that considers the free energy of the surface monolayer to explain the orientation-dependent phase separation in GaAsSb. In the proposed model, only the interaction between the second nearest-neighboring atoms sitting on the same monolayer contributes to the interaction parameter. Consequently, the parameter reduces to Ω/2 and Ω/3 for (111)B GaAsSb and (100) GaAsSb, where Ω denotes the parameter of bulk GaAsSb. By including the strain effect, the proposed model thoroughly elucidates the immiscibility behavior of (111)B GaAsSb and (100) GaAsSb. ► (111)B GaAsSb exhibits severe phase separation than (100) GaAsSb. ► We propose a model to calculate the monolayer free energy of different planes. ► Monolayer model suggests that (111)B GaAsSb has larger interaction parameter. ► Monolayer model including strain well explains the immiscibility of GaAsSb.