Effect of DX centers in the vertical transport properties of semiconductor superlattices

DX centers have been detected in vertical transport experiments of GaAs-AlAs superlattices. We studied miniband conduction properties of such semiconductor structures in presence of high hydrostatic pressures and controlled temperature. Hystheresis effect in the current-voltage characteristics was observed. We show that miniband transport properties are dependent on the path of the pressure cycle imposed to the sample. It is clear from our results that DX centers are present in the active superlattice region. We propose that the energy associated with DX states in superlattice results from a "hybridization" of DX centers of both GaAs and AlAs bulk materials.