Electronic structure of quantum wells embedded inshort-period superlattices with graded interfaces

Abstract

In the present study we investigate the effect ofcomponent interdiffusion across the interfaces on theelectronic structure of a quantum well embedded in ashort-period superlattice. We calculate the energies of thebound states for an 18 monolayer (5 nm) thick GaAs quantum wellembedded in an (AlAs)4/(GaAs)8 superlattice incomparison with two AlxGa1-xAs/GaAs(x = 1 and 0.33) single quantum wells with the samethickness. The calculations are made within the framework of theenvelope-function approximation. The behaviour of the lowestelectron and hole bound states is studied for values of thediffusion length from 0 to 4 monolayers. The contribution of theX-point conduction band minima to the electronic structure isdiscussed. The calculated transition energies are shown to be inagreement with photoluminescence spectra of such structures. Thepresented approach can be used to assess the effect of thecomponent intermixing on the electronic structure of variouscomplex multilayered systems.