Electronic band-structure engineering of GaAs/AlxGa1 xAs quantum well superlattices with substructures

We report a theoretical investigation on the band structures of electrons in both infinite and finite semiconductor quantum well/ barrier superlattices with each unit cell containing alternately two types of materials. When the unit cell of a superlattice, made of GaAs and AlxGa1 xAs, is further divided into four and six sublayers of these two materials, narrower passbands and/or broad stopbands can be obtained for electrons with energy slightly larger than the potential barrier. When a finite superlattice has two different periods and each unit cell contains six sublayers of alternating GaAs and AlxGa1 xAs, very sharp passbands can be obtained for electron energy right below and above the potential barrier. The results may be used to build a high-Q electron energy filter. # 2003 Elsevier Science B.V. All rights reserved.