Binding energies of excitons in type-II GaAs-AlAs quantum-well structures in the presence of a magnetic field

We report a calculation of the binding energies of both the heavy-hole and the light-hole excitons in type-II GaAs-AlAs quantum wells as a function of the size of the AlAs layer (or the GaAs layer) in the presence of a magnetic field applied parallel to the direction of growth. We follow a variational approach and assume that the electrons and holes are confined in infinite potential barriers. For a given set of values of GaAs- and AlAs-layer thicknesses, the binding energies of excitons are found to increase with increasing magnetic field.