Energy level control for self-assembled InAs quantum dots utilizing a thin AlAs layer

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Abstract
Ground-state energy of InAs quantum dots (QDs) in the GaAs matrix can be changed significantly by introducing a thin AlAs layer (1 nm). The photoluminescence (PL) peak position of the QDs grown directly on the thin AlAs layer is blueshifted by 171 meV from that of the QDs grown without the AlAs layer. QDs grown on an additional GaAs thin layer on top of the AlAs layer have PL peaks systematically redshifted to lower energy as the GaAs layer becomes thicker. Time-resolved PL shows that the QDs have similar lifetimes, attesting to the fact that all the QDs grown in this way are of high quality, although the energy level change is large and a thin AlAs layer is introduced.