Oscillator strength and optical selection rule of excitons in quantum wells

An investigation is made of the optical selection rules and oscillator strengths of ground-state and excited-state excitons in quantum wells (GaAs/Ga0.75{Al}0.25$As) with well widths ranging from 50 to 200 A{}. Our results show that, owing to the dependence of the exciton wave function on its polar angle within the plane parallel to the interface, only a single component of the spinor wave function contributes to the oscillator strength of optical transitions. As compared with interband transitions, the ``parity-allowed'' rule, namely, {Δ}n=0,2,..., becomes operative for ground-state excitons. But the hybridization of heavy- and light-hole states still plays an important role for the oscillator strength of excited-state excitons.