Raman study of confined TO phonons in GaAs/AlAs superlattices grown on GaAs (311)A and B surfaces

✍ Scribed by V.A. Volodin; M.D. Efremov; V.V. Preobrazhenskii; B.R. Semyagin; V.V. Bolotov

• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 116 KB
• Volume: 26
• Category: Article
• ISSN: 0749-6036
• DOI: 10.1006/spmi.1999.0699

✦ Synopsis

The use of Raman scattering in different polarization geometries makes it possible to observe the splitting of transverse optical (TO) phonon modes confined in GaAs/AlAs superlattices grown on faceted GaAs (311)A surfaces. The frequencies of TO modes with atomic displacements in the direction along the facets were observed to be higher than in the transverse one. Increased splitting, up to 3.5 cm -1 , was observed for (311)A superlattices when the average thickness of the GaAs layers was 6 monolayers or less. The splitting was absent in superlattices grown on (311)B surfaces under the same conditions. The effect of splitting is reputed to be caused by corrugation of GaAs/AlAs (311)A interfaces and formation of lateral superlattices or arrays of quantum wires, depending on the GaAs layer thickness.