Electric field induced [MATH]-X transition in GaAs-AlAs coupled quantum well structures

Phonon replicas are investigated at the electric field induced Γ-X transition in GaAs/AlAs coupled quantum well structures by photoluminescence spectroscopy. In the real- and k-space indirect regime the observed replicas are assigned to AlAs LO, TO and LA zone-edge phonons. At the indirect-direct transition those phonons disappear and a new replica emerges, which is assigned as a GaAs-LO phonon at the Γ-point. The observed phonon replicas are shown to be a local probe for the distribution of the ground state electronic wave function in the GaAs/AlAs coupled quantum well structure.