Excitation Density and Temperature Dependent Photoluminescence of InGaAs Self-Assembled Quantum Dots

In this paper, we shall report on the excitation density and temperature dependent photoluminescence produced by discrete energy levels from InGaAs self-assembled quantum dots. While increasing the photoexcitation density, five peaks originating from discrete energy levels of quantum dot and welting layer are observed. By deconvoluting these spectra using multiple Gaussian fit, the intensity of each state is saturated following its degeneracy. We describe the lateral confinement of quantum dots using a parabolic potential model. The saturated values are in good agreement with the degeneracy of this potential type. From the temperature dependent photoluminescence, we observed the thermally activated quenching of each state. Our results suggest that the wetting layer acts as a barrier to the carrier thermallization processes offering a two dimensional path for inter-dot coupling.