engleski

InGaAs/GaAs quantum dots within an effective approach

An effective approach for describing the electronic structure of InGaAs/GaAs quantum dots (QDs) is presented. We model QDs based on a single sub-band approach with an energy-dependent electron effective mass. The model assumes that the total effect of inter-band interactions, strain and piezoelectricity can be taken into account by an effective potential. Using this approximation, we define a strength parameter of the effective potential to reproduce capacitance–gate-voltage (CV) experimental data for InAs/GaAs QDs. In the present work, we expand the model to describe InxGa1−xAs QDs with significant Ga fractions. We find that our model accurately describes CV and photoluminescence (PL) data for QDs, assuming 22% Ga fractions, and also reproduces the experimental data for Coulomb shifts of exciton complexes (X−, X+, XX). We compared our results with those from atomistic pseudopotential and eight-band kp-Hamiltonian approaches. The strength of the electron and heavy hole confinements is found to be weaker in the kp-model than in the atomistic pseudopotential approach.

quantum dots ; single carrier levels ; Coulomb interaction ; excitons ; opitical properties

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