PHOTOLUMINESCENCE STUDY OF GAAS ALGAAS QUANTUM-WELL HETEROSTRUCTURE INTERFACES/

Photoluminescence (PL) is used to study the interface properties of Ga As/AlGaAs quantum well (QW) heterostructures prepared by molecular bea m epitaxy with growth interruption (GI). The discrete luminescence lin es observed for the sample with GI are assigned to the splitting of th e heavy-hole exciton associated with heterointerface islands with the lateral size greater than exciton diameter and mean height less than o ne monolayer, and the spectra have the Gaussian lineshapes. The result s strongly support the microroughness model. We also study the tempera ture dependence of the exciton energies and find that excitons are loc alized at the interface roughness at low temperature even in the sampl e with GI. The lateral size of the microroughness of the GI sample is estimated to be less than 5 nm from the exciton localization energy.