Interface-related effects on confined excitons in GaAs/AlxGa1−xAs single quantum wells

Confined excitons in non-abrupt GaAs/AlxGa1−xAs single quantum wells are studied. The graded interfaces are described taking into account fluctuations in their thickness a and positioning α with respect to the abrupt interface picture. Numerical results for confined (0,0),(1,1) and (0,2) excitons in GaAs/Al0.3Ga0.7As quantum wells show that while the interfacial fluctuations produce small changes (<0.5 meV) in the exciton binding energies, the confined exciton energies can be red- or blue-shifted as much as 25 meV for wells with mean width of 50 Å and 2 ML wide interfaces.