RESONANT RAMAN-SCATTERING AROUND THE E0 TRANSITION OF ALAS/INAS STRAINED-LAYER SUPERLATTICES

We present an analysis of the resonant behavior of Raman scattering when exciting around the E0 transition of AlAs/InAs strained-layer superlattices grown on GaAs. To preserve the crystalline quality of the superlattices, the layers of InAs (well material) are kept at very low thicknesses while the AlAs barriers are thick. We observe a shift of the AlAs LO-phonon peak, when exciting near resonance with transitions localized in the InAs well, that is not attributable to strain effects. This observed effect is well explained in terms of the different electron-phonon coupling strengths for the LO1 phonon and for higher-order (LO3, LO5, ...) phonons.