Interfacial fluctuations effects on confined excitons in single GaAs/AlxGa1−xAs quantum wells

We perform a more realistic description of normal and inverted graded interfaces to study confined excitons in non-abrupt GaAs/AlxGa1−xAs single quantum wells (QWs). Interfacial fluctuations are considered in the model through their thicknesses bi and positioning α with respect to the abrupt interface picture. Numerical results are obtained for the well width dependence of the total and binding exciton energies [(0,0), (1,1) and (0,2)] in GaAs/Al0.35Ga0.65As single QWs. We show that interfacial fluctuations produce small changes (<0.5 meV) in the exciton binding energies, while the graded interfaces can blueshift (redshift) the confined exciton energy as much as 35 meV (−17 meV) when the mean QW width is 50 Å and the interface thickness 4 monolayers (ML).