Growth optimization of spin-transport barriers used for spin-polarized light-emitting diodes based on InGaAs quantum dots

Abstract

We have studied GaAs and AlGaAs barriers for the purpose of improving spin-transport performance in spin-polarized light-emitting diodes (LEDs) based on self-assembled quantum dots (QDs) of InGaAs. In the spin-LED utilizing a spin-functional optical active layer of In-based self-assembled QDs, growth temperatures of top barriers of GaAs and AlGaAs were reduced to suppress indium diffusion from the QDs into the barriers after forming the QDs. We show a significant improvement of spin-transport property as well as of carrier-transport one with increasing growth temperature of the Al0.1Ga0.9As barrier from 580 to 640 °C, while luminescent spectral energy and shape of the QDs are not markedly affected.