Investigation of intersubband transitions in truncated pyramid-shaped InAs/GaAs quantum dots coupled to wetting layer: Strain and size matter

Abstract

In this paper, we theoretically report competition behaviour of size and strain effects on the InAs/GaAs quantum dots (QDs) eigenenergies, the envelop functions and also transition energies of the z-polarized WL-to-S states with varying the QD height and WL thickness. The obtained result for the bounded ground state of S implies that although the size-dependence behaviour with the inclusive of the strain effects generally resembles that of unstrained case, the energy values have changed appreciably for the short dots with value of 200 meV and for tall dots with nearly 300 meV. The competition behaviour of strain and size effects on the electronic properties of the structure revealed that the WL state is more sensitive to the size and WL thickness in presence of strain. For the weakly bounded WL state, the envelop function was localized in the wetting layer or bulk regions as a continuum state for the thick WL within the strain-modified structure. The calculated optical wavelength from z-polarized transition of WL-to-S in the strain-modified structure agrees well with previous experimental photoluminescence data from other studies.