EFFECT OF MAGNETIC-FIELDS ON EXCITON BINDING-ENERGIES IN TYPE-II GAAS-ALAS QUANTUM-WELL STRUCTURES

We calculate the binding energies of both the light-hole and heavy-hole excitons in type-II GaAs-AlAs quantum wells in the presence of a magnetic field applied parallel to the axis of growth. Two methods are applied and compared: a variational approach and a perturbation method. The exciton binding energies are calculated assuming infinite potential barriers. The behavior of the exciton binding energies as functions of well widths and the magnetic field is discussed. For a given value of the magnetic field, the exciton binding energies are found to be larger than the zero-magnetic-field case. Results obtained from both methods are compared.