Effects of a thin (In)GaAs layer on the structural and optical properties of InAsInAlGaAs quantum dots

The introduction of a thin (In)GaAs layer between an InAs quantum dot (QD) layer and an InAlGaAs layer altered the structural and optical properties of self-assembled InAsInAlGaAs QDs grown on InP (001) substrates. The emission peak of the InAs QDs on a thin In0.32 Ga0.68 As layer grown on InAlGaAs was redshifted with increasing thickness of the In0.32 Ga0.68 As layer. However, the photoluminescence (PL) peak of the InAs QDs on a thin GaAs layer grown on InAlGaAs was blueshifted with increasing thickness of the GaAs layer, and the PL yield was also drastically decreased. Although the lattice constants of both In0.32 Ga0.68 As and GaAs are smaller than that of InAlGaAs, which would be expected to have a similar type of strain modulation, the structural and optical properties of the InAs QDs were significantly different because of the different nucleation characteristics of QDs.