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Shallow Donor Impurity States with Excitonic Contribution in GaAs/AlGaAs and CdTe/CdSe Truncated Conical Quantum Dots under Applied Magnetic Field

Using the effective mass approximation in a parabolic two-band model, we studied the effects of the geometrical parameters, on the electron and hole states, in two truncated conical quantum dots: (i) GaAs-(Ga,Al)As in the presence of a shallow donor impurity and under an applied magnetic field and (...

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Autores principales: Pulgar-Velásquez, Lorenz, Sierra-Ortega, José, Vinasco, Juan A., Laroze, David, Radu, Adrian, Kasapoglu, Esin, Restrepo, Ricardo L., Gil-Corrales, John A., Morales, Alvaro L., Duque, Carlos A.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8619694/
https://www.ncbi.nlm.nih.gov/pubmed/34835595
http://dx.doi.org/10.3390/nano11112832
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author Pulgar-Velásquez, Lorenz
Sierra-Ortega, José
Vinasco, Juan A.
Laroze, David
Radu, Adrian
Kasapoglu, Esin
Restrepo, Ricardo L.
Gil-Corrales, John A.
Morales, Alvaro L.
Duque, Carlos A.
author_facet Pulgar-Velásquez, Lorenz
Sierra-Ortega, José
Vinasco, Juan A.
Laroze, David
Radu, Adrian
Kasapoglu, Esin
Restrepo, Ricardo L.
Gil-Corrales, John A.
Morales, Alvaro L.
Duque, Carlos A.
author_sort Pulgar-Velásquez, Lorenz
collection PubMed
description Using the effective mass approximation in a parabolic two-band model, we studied the effects of the geometrical parameters, on the electron and hole states, in two truncated conical quantum dots: (i) GaAs-(Ga,Al)As in the presence of a shallow donor impurity and under an applied magnetic field and (ii) CdSe–CdTe core–shell type-II quantum dot. For the first system, the impurity position and the applied magnetic field direction were chosen to preserve the system’s azimuthal symmetry. The finite element method obtains the solution of the Schrödinger equations for electron or hole with or without impurity with an adaptive discretization of a triangular mesh. The interaction of the electron and hole states is calculated in a first-order perturbative approximation. This study shows that the magnetic field and donor impurities are relevant factors in the optoelectronic properties of conical quantum dots. Additionally, for the CdSe–CdTe quantum dot, where, again, the axial symmetry is preserved, a switch between direct and indirect exciton is possible to be controlled through geometry.
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spelling pubmed-86196942021-11-27 Shallow Donor Impurity States with Excitonic Contribution in GaAs/AlGaAs and CdTe/CdSe Truncated Conical Quantum Dots under Applied Magnetic Field Pulgar-Velásquez, Lorenz Sierra-Ortega, José Vinasco, Juan A. Laroze, David Radu, Adrian Kasapoglu, Esin Restrepo, Ricardo L. Gil-Corrales, John A. Morales, Alvaro L. Duque, Carlos A. Nanomaterials (Basel) Article Using the effective mass approximation in a parabolic two-band model, we studied the effects of the geometrical parameters, on the electron and hole states, in two truncated conical quantum dots: (i) GaAs-(Ga,Al)As in the presence of a shallow donor impurity and under an applied magnetic field and (ii) CdSe–CdTe core–shell type-II quantum dot. For the first system, the impurity position and the applied magnetic field direction were chosen to preserve the system’s azimuthal symmetry. The finite element method obtains the solution of the Schrödinger equations for electron or hole with or without impurity with an adaptive discretization of a triangular mesh. The interaction of the electron and hole states is calculated in a first-order perturbative approximation. This study shows that the magnetic field and donor impurities are relevant factors in the optoelectronic properties of conical quantum dots. Additionally, for the CdSe–CdTe quantum dot, where, again, the axial symmetry is preserved, a switch between direct and indirect exciton is possible to be controlled through geometry. MDPI 2021-10-25 /pmc/articles/PMC8619694/ /pubmed/34835595 http://dx.doi.org/10.3390/nano11112832 Text en © 2021 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Pulgar-Velásquez, Lorenz
Sierra-Ortega, José
Vinasco, Juan A.
Laroze, David
Radu, Adrian
Kasapoglu, Esin
Restrepo, Ricardo L.
Gil-Corrales, John A.
Morales, Alvaro L.
Duque, Carlos A.
Shallow Donor Impurity States with Excitonic Contribution in GaAs/AlGaAs and CdTe/CdSe Truncated Conical Quantum Dots under Applied Magnetic Field
title Shallow Donor Impurity States with Excitonic Contribution in GaAs/AlGaAs and CdTe/CdSe Truncated Conical Quantum Dots under Applied Magnetic Field
title_full Shallow Donor Impurity States with Excitonic Contribution in GaAs/AlGaAs and CdTe/CdSe Truncated Conical Quantum Dots under Applied Magnetic Field
title_fullStr Shallow Donor Impurity States with Excitonic Contribution in GaAs/AlGaAs and CdTe/CdSe Truncated Conical Quantum Dots under Applied Magnetic Field
title_full_unstemmed Shallow Donor Impurity States with Excitonic Contribution in GaAs/AlGaAs and CdTe/CdSe Truncated Conical Quantum Dots under Applied Magnetic Field
title_short Shallow Donor Impurity States with Excitonic Contribution in GaAs/AlGaAs and CdTe/CdSe Truncated Conical Quantum Dots under Applied Magnetic Field
title_sort shallow donor impurity states with excitonic contribution in gaas/algaas and cdte/cdse truncated conical quantum dots under applied magnetic field
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8619694/
https://www.ncbi.nlm.nih.gov/pubmed/34835595
http://dx.doi.org/10.3390/nano11112832
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