Exciton states in GaAs/AlGaAs Bragg confining structures studied by resonant Raman scattering

Abstract

The LO phonon resonant Raman scattering is studied in GaAs/${\mathrm{Al}}_{0.32}$${\mathrm{Ga}}_{0.68}$As Bragg confining structures and in a similar (reference) superlattice. Strong resonances, with a large outgoing/incoming beam intensity ratio, are observed in the spectral range of the (${\mathit{e}}_{\mathit{B}}$:${\mathit{hh}}_{\mathit{B}}$) Bragg confined excitons as well as in the (${\mathit{e}}_{1}$:${\mathit{hh}}_{1}$) exciton band. The resonance profiles are analyzed in terms of a model of exciton scattering by interface and alloy potential fluctuations. The Bragg confined 1S excitons are found to be virtually two dimensional, while those of the superlattice are intermediate between two and three dimensions.