Effects of GaAs on photoluminescence properties of self-assembled InAs quantum dots

Room temperature photoluminescence (PL) spectra of InAs self-assembled quantum dots (QDs) deposited on a GaAs/InP and InP substrate are investigated. From the PL spectra, we find that the peak position of InAs QDs appears redshift from 0.795 to 0.785 eV after we insert a thin tensile GaAs layer between InAs QD layer and InP buffer layer. In order to explain this phenomenon in theory, we examine the strain tenser in InAs quantum dots by using a valence force field model and use a five-band Ic p formalism to obtain the electronic structure. The calculated results show that the ground transition energy decreases fi om 0.789 to 0.780 eV when the thin GaAs layer is inserted. Therefore, the PL peak position should appear redshift as shown in the experiment.