Effect of barrier configuration on excitonic recombination in Ga0.47In0.53As/Al0.48In0.52As multi quantum well structures

Photoluminescence and photoluminescence excitation spectroscopy on Ga0.47In0.53As multi quantum wells confined either by homogeneous ternary Al0.48In0.52As barriers or by Ga0.47In0.53As/Al0.48In0.52As short-period superlattice (SPS) barriers show that the confinement by SPS barriers improves the edge luminescence significantly. The spectral width of the free-exciton absorption and the low-temperature emission peak as well as the Stokes shift between emission and excitation spectra are reduced as compared to samples clad by homogeneous ternary Al0.48In0.52As barriers. The dominant low-temperature emission line in the SPS-clad Ga0.47In0.53As multi quantum wells is assigned to intrinsic excitonic recombination. The small Stokes shift of the excitonic luminescence line can be explained by intrinsic relaxation processes caused by monolayer fluctuation of the well width and by statistical fluctuation of the composition of the ternary Ga0.47In0.53As well material. (IAF