Dependence of the microstructural and the optical properties on the GaAs spacer thickness in InAs/GaAs double quantum dots grown by using the Indium-flush procedure

Abstract

The dependences of the microstructural and the optical properties on the GaAs spacer thickness in InAs/GaAs double quantum dots (QDs) with different GaAs spacer layers grown using molecular beam epitaxy (MBE) with an indium-flush method were analyzed. Transmission electron microscopy (TEM) measurements were performed to characterize the microstructural properties of the InAs/GaAs double QDs and photoluminescence (PL) measurements were carried out to investigate the dependences of the full width at half maximum (FWHM) and the activation energy on the GaAs spacer layer thickness in the InAs/GaAs double QDs. The results of TEM measurements showed that the InAs/GaAs double QDs were almost the same. The PL peak position corresponding to the transition shifted to higher energy with increasing GaAs spacer thickness due to the coupling effect, and the activation energy of the electrons confined in the InAs QDs decreased with decreasing GaAs spacer thickness due to the strain effect.