Transverse optical phonon splitting in GaAs/AlAs superlattices grown on the GaAs(311) surface studied by the method of Raman light scattering

GaAsn/AlAsm superlattices grown on the GaAs (311)A and (311)B surfaces by m olecular-beam epitaxy were studied by Raman light scattering. The form of t he Raman scattering tensor allowed the TOy and TOx modes to be separately o bserved using various scattering geometries (the y and x axes correspond to atomic displacements along and across facets formed on the (311)A surface, respectively). The TO1(y) and TO1(x) modes exhibited splitting in superlat tices grown on a faceted GaAs(311)A surface. The degree of splitting increa sed for superlattices with an average GaAs layer thickness of 6 monoatomic layers and less. No splitting was observed for superlattices grown under th e same conditions on the (311)B surface, which indicates that the splitting effect is probably due to the formation of GaAs quantum wires on the facet ed (311)A surface. (C) 2000 MAIK "Nauka/Interperiodica".