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

In the present study we investigate the effect of component interdiffusion across the interfaces on the electronic structure of a quantum well embedde d in a short period superlattice. We calculate the energies of the bound st ates for an 18 monolayer (5 nm) thick GaAs quantum well embedded in an (AlA s)(4)/(GaAs)(8) superlattice in comparison with two AlxGa1-xAs/GaAs (x = 1 and 0.33) single quantum wells with the same thickness. The calculations ar e made within the framework of the envelope-function approximation. The beh aviour of the lowest electron and hole bound states is studied for values o f the diffusion length from 0 to 4 monolayers. The contribution of the X-po int conduction band minima to the electronic structure is discussed. The ca lculated transition energies are shown to be in agreement with photolumines cence spectra of such structures. The presented approach can be used to ass ess the effect of the component intermixing on the electronic structure of various complex multilayered systems.