The INGAAS/GAAS Quantum Dots Under Effective and Ab Initio Treatments: Comparison and Results

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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. It is found that our model accurately describes CV and photoluminescence (PL) data for QDs with assumed 22% Ga fraction. The model also reproduces the experimental data for Coulomb shifts of exciton complexes (X+, X-, XX). We compared our results with atomistic pseudopetential and ab initio calculations obtained with an 8-band kp-Hamiltonian approach. The strength of the electron and heavy hole confinement is found to be weaker in the ab initio model than in the atomistic pseudopotential approach.

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Journal: TechConnect Briefs
Volume: 1, Nanotechnology 2009: Fabrication, Particles, Characterization, MEMS, Electronics and Photonics
Published: May 3, 2009
Pages: 578 - 581
Industry sectors: Advanced Materials & Manufacturing | Sensors, MEMS, Electronics
Topics: Nanoelectronics, Photonic Materials & Devices
ISBN: 978-1-4398-1782-7