Surfactant-Induced Alterations of Epitaxial Orientation in β-In2S3 Layers on InP

InP(111) surfaces are sulfurized using vaporized Sb2S3 and Bi2S3 as the providers of S. Temperatures higher than 340 degrees C are required to substitute the Sb atoms in Sb2S3 with the In atoms from the substrates although such a substitution occurs regardless of the temperature when Bi2S3 is used. In beta-In2S3 layers produced as a consequence of the sulfurization, the epitaxial growth takes place not only in the generally favored (103) orientation but also in a source-dependent additional orientation. The primary coexisting orientation is (110) and (109) for using Sb2S3 and Bi2S3, respectively. The surface free energy is changed by the coverage with Sb and Bi generated in the substitution, giving rise to the alterations of the growth orientation. While the absence of the substitution reaction results in depositing polycrystalline Sb2S3 films at medium temperatures, the deposition is made possible by thermally activated sticking of Sb2S3 species to the InP surfaces. It is also shown that the sulfurization and the deposition of the Sb2S3 films are restricted when excess Sb is added to the Sb2S3 vapor.

Automated summary

The study investigates the sulfurization of InP(111) surfaces using vaporized Sb2S3 and Bi2S3, exploring the effects of temperature on the substitution of atoms and epitaxial growth orientation. It reveals that the coverage with Sb and Bi changes the surface free energy, leading to alterations in growth orientation. Additionally, the deposition of polycrystalline Sb2S3 films is facilitated by the thermally activated sticking of Sb2S3 species to the InP surfaces.