Effective approach for strained InAs/GaAs quantum structures

We model an InAs/GaAs quantum dot (QD) with a single sub-band approach and an energy dependent effective electron mass. Confined states of carriers are formed by the band-gap potential. An additional potential is included in the model to simulate the combined effect of strains and piezoelectricity. It is shown that this effect may be taken into account in an effective manner. The model allows us to reproduce the results of ab initio calculations. To prove the adequacy of our model, we compare the results obtained for energy spectra of few electrons, tunneling into InAs/GaAs QD, with experimental capacitance–gate-voltage data. The non-parabolic effect taken into account in this calculation is quite visible for QD sizes considered. We discuss the possibility to describe the CV experimental data with electron confinement obtained from realistic model calculations, as well as limitations of these models in the case of extremely small QD size.