Raman study of interface roughness in (GaAs)(n)(AlAs)(n) superlattices grown on tilted surfaces: Evidence of corrugation of the (113) interface

The optical phonons in ultrathin-layer GaAs/AlAs superlattices grown in different crystal directions have been studied by Raman scattering. The results give evidence of the formation of different interfaces depending on the growth direction. The strongest influence of the interdiffusion was found for directions lying between the [001] and [110] axes. Raman spectra of the (113) A-oriented (GaAs)(n)/(AlAs)(n) superlattices show the splitting of optical phonons confined in the narrow and in the wide parts of the corrugated layers. The analysis of the observed splitting reveals that the corrugation is two monolayers high.