Determination Of Gamma-X Transfer Rates In Type-Ii (Al)Gaas/Alas Superlattices

We have experimentally determined the Γ-X transfer rates in a type II GaAs/AlAs short period superlattice as well as in a type II Al x Ga 1− x As/AlAs superlattice. Transfer times on a subpicosecond- and picosecond-timescale are observed depending on the layer-thickness. We conclude from temperature dependent measurements that for thicker layers electron-phonon scattering is the dominant scattering mechanism whereas for thinner layers interface roughness scattering may become dominant.