Molecular beam epitaxy of GaAs/AlGaAs superlattice heterostructures on nonplanar substrates

Abstract

GaAs/AlGaAs superlattice heterostructures with layer thicknesses ≲100 Å were grown by molecular beam epitaxy on nonplanar GaAs substrates. The resulting superlattices exhibit different periods, depending on the crystal plane on which they grow. Period variation of more than 50%, from 180 to 80 Å, was obtained for adjacent superlattice sections. The transition between regions of different periodicity was mostly smooth and occurred within lateral dimensions ≲100 Å. Our results suggest that molecular beam epitaxy of superlattice heterostructures on patterned substrates provides a method for obtaining controllable lateral variations in physical properties which depend on the superlattice period. In particular, by growing quantum well heterostructures on nonplanar substrates, it might be possible to utilize the strong dependence of the carrier confinement energy on the well thickness in order to achieve lateral carrier confinement.