Effects of a thin AlAs layer on InAs quantum dot electronic structure

The influence of a thin AlAs layer (1 nm) located at different positions inside a GaAs matrix on the electronic states of nearby deposited InAs quantum dots is theoretically investigated. Calculations are performed within the three-dimensional one-band effective mass model including mass dependence on energy and position. In order to provide a realistic description of the wave function diffusion outside the dot, finite confinement barriers are considered. It is shown that the presence of the AlAs high potential barrier can account for the reported experimental blueshift when the AlAs layer is grown as a capping material, but this is not the case when the AlAs layer is grown in the substrate. An alternative explanation of the experimental data [Kim et al., J. Appl. Phys. 91, 5055 (2002)] based on our calculations is proposed.