EXCITON CONFINEMENT IN GAAS QUANTUM BARRIERS

We report the observation in a III-V semiconductor quantum-well structure, of free excitons with wave function mainly confined inside the barrier material GaAs. The confined-exciton energy falls between the fundamental level of the bulk three-dimensional exciton and its continuum of states. The confinement-energy values, obtained by an ad hoc designed luminescence self-absorption spectroscopy method, are consistent with the barrier parameters.