Electronic structure of self-assembled InAs/InP quantum dots: Comparison with self-assembled InAs/GaAs quantum dots

We investigate the electronic structure of the InAs/InP quantum dots using an atomistic pseudopotential method and compare it to that of the InAs/GaAs quantum dots (QDs). We show that even though the InAs/InP and InAs/GaAs dots have the same dot material, their electronic structures differ significantly in certain aspects, especially for holes: (i) The hole levels have a much larger energy spacing in the InAs/InP dots than in the InAs/GaAs dots of corresponding size. (ii) Furthermore, in contrast with the InAs/GaAs dots, where the sizable hole p, d intrashell level splitting smashes the energy level shell structure, the InAs/InP QDs have a well defined energy level shell structure with small p, d level splitting, for holes. (iii) The fundamental exciton energies of the InAs/InP dots are calculated to be around 0.8 eV (~1.55 µm), about 200 meV lower than those of typical InAs/GaAs QDs, mainly due to the smaller lattice mismatch in the InAs/InP dots. (iv) The widths of the exciton P shell and D shell are much narrower in the InAs/InP dots than in the InAs/GaAs dots. (v) The InAs/GaAs and InAs/InP dots have a reversed light polarization anisotropy along the [100] and [1[overline 1]0] directions.