Optical Characterization Of GaAs/AlxGai-xAs Quantum Well Structures And Superlattices By Photoluminescence And Photoexcitation Spectroscopy.

We present (I) low temperature excitation-wavelength-dependent photoluminescence studies in GaAs/AlxGai-xAs quantum well structures, which reveal the well thickness variations along the MBE growth direction, and (II) the photoluminescence excitation spectroscopy work carried out in the region of unconfined transitions with a series of GaAs/AlxGal-xAs superlattices which have a fixed well size and aluminum concentration in the barrier. We have found that the changes in the barrier widths of the superlattice samples can drastically affect the strengths and energies of the unconfined transitions.