ABOVE BARRIER EXCITON CONFINEMENT IN INGAAS GAAS MULTIPLE-QUANTUM-WELL STRUCTURES/

Exciton confinement in the GaAs barriers of InGaAs/GaAs multiple-quant um-well structures is demonstrated by luminescence self-absorption and photoluminescence excitation spectroscopies. The confinement energy a nd absorption linewidth depend on the barrier width as predicted by a plain quantum mechanical model. For thin barriers, a splitting in the experimental lineshape is accounted for by including into the theoreti cal model the interaction among excitons confined in individual barrie rs. Evidence for a transition between a hole state in the well and an electron state confined in the barrier is also reported, which provide s a direct way for estimating the band offsets.