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4 results on '"S. Ben Radhia"'

1. Multiband k·p Model for Tetragonal Crystals: Application to Hybrid Halide Perovskite Nanocrystals

Author

K. Boujdaria, S. Ben Radhia, R. Ben Aich, M. Chamarro, C. Testelin, Université de Carthage - University of Carthage, Institut des Nanosciences de Paris (INSP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Photonique et cohérence de spin (INSP-E12), and Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)

Subjects
010302 applied physics, Materials science, Halide, 02 engineering and technology, 021001 nanoscience & nanotechnology, 01 natural sciences, 3. Good health, Condensed Matter::Materials Science, Tetragonal crystal system, Crystallography, Nanocrystal, Condensed Matter::Superconductivity, 0103 physical sciences, Molecular symmetry, Condensed Matter::Strongly Correlated Electrons, General Materials Science, Physical and Theoretical Chemistry, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], 0210 nano-technology, Electronic band structure, ComputingMilieux_MISCELLANEOUS, Perovskite (structure)
Abstract

We investigate the theoretical band structure of organic–inorganic perovskites APbX3 with tetragonal crystal structure. Using D4h point group symmetry properties, we derive a general 16-band Hamilt...

Published
2020
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2. Neutral, charged excitons and biexcitons in strain-free and asymmetric GaAs quantum dots fabricated by local droplet etching

Author

Christophe Testelin, Oliver G. Schmidt, M. Yahyaoui, Eugenio Zallo, K. Boujdaria, Z. Trabelsi, Maria Chamarro, Paola Atkinson, S. Ben Radhia, Institut de Combustion, Aérothermique, Réactivité et Environnement (ICARE), Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut des Sciences de l'Ingénierie et des Systèmes (INSIS), Université de Carthage - University of Carthage, Max-Planck-Institut für Festkörperforschung, Max-Planck-Gesellschaft, Institut des Nanosciences de Paris (INSP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Photonique et cohérence de spin (INSP-E12), and Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS]Physics [physics], Materials science, Exciton, Exchange interaction, Biophysics, 02 engineering and technology, General Chemistry, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Biochemistry, Molecular physics, Atomic and Molecular Physics, and Optics, Symmetry (physics), Quantum dot, Etching (microfabrication), 0103 physical sciences, Coulomb, 010306 general physics, 0210 nano-technology, Anisotropy, Biexciton, ComputingMilieux_MISCELLANEOUS
Abstract

We present an experimental and theoretical study of the optical properties of asymmetric strain-free GaAs quantum dots (QDs) fabricated by filling of self-organized nanoholes (NHs) created by local droplet etching. The energy levels are calculated within the effective mass approximation using as input a model anisotropic QD shape with C 2 v symmetry based on atomic force microscopy (AFM) profiles of NHs. The influence of the QD height and shape anisotropy on the exciton emission energy and the s- p x and s- p y energy splittings is studied theoretically. The experimentally observed bound nature of excitonic states is well reproduced by our theoretical approach which includes direct Coulomb energies and correlation effects. We investigate the fine-structure splitting (FSS) of the neutral exciton as a function of dot size. Theoretical calculations of the long-range electron-hole (e-h) exchange interaction predict an increase of the FSS with decreasing QD height, which describes well the experimental trend.

Published
2018
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3. Optical properties of type-II AlInAs/AlGaAs quantum dots by photoluminescence studies

Author

Christophe Testelin, Aristide Lemaître, F. Bernardot, K. Boujdaria, I. Saïdi, S. Ben Radhia, R. Neffati, Institut d'Électronique et des Technologies du numéRique (IETR), Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Université de Carthage - University of Carthage, Laboratoire de photonique et de nanostructures (LPN), Centre National de la Recherche Scientifique (CNRS), Institut des Nanosciences de Paris (INSP), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Photonique et cohérence de spin (INSP-E12), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Nanostructures et systèmes quantiques (INSP-E1), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Nantes Université (NU)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), and Université de Nantes (UN)-Université de Rennes 1 (UR1)

Subjects
010302 applied physics, [PHYS]Physics [physics], Photoluminescence, Materials science, Condensed matter physics, General Physics and Astronomy, 02 engineering and technology, Electron, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, 021001 nanoscience & nanotechnology, 01 natural sciences, Symmetry (physics), Characterization (materials science), Gallium arsenide, Matrix (mathematics), chemistry.chemical_compound, chemistry, Quantum dot, 0103 physical sciences, 0210 nano-technology, Electronic band structure, ComputingMilieux_MISCELLANEOUS
Abstract

We report photoluminescence (PL) characterization and model simulation of AlInAs/AlGaAs type-II quantum dots (QDs). A thorough and precise determination of the band parameters for QD and matrix materials is given, focusing on the effects of alloy composition and strain state on the electronic properties. Origins of experimentally observed PL emission peaks are identified through a comparison with the band lineup theoretically determined in this work. We interpret the QD emission as originating from indirect type-II transitions involving electrons in the barrier X valley and heavy holes with S and P symmetry.

Published
2016
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4. Effects of strain on the optoelectronic properties of annealed InGaAs/GaAs self-assembled quantum dots

Author

Christophe Testelin, M. Yahyaoui, K. Boujdaria, S. Ben Radhia, B. Eble, Aristide Lemaître, Maria Chamarro, K. Sellami, Institut des Nanosciences de Paris (INSP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de photonique et de nanostructures (LPN), and Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Photoluminescence, business.industry, Annealing (metallurgy), exciton energy, quantum dots, Electron, Condensed Matter Physics, Fick's laws of diffusion, Electronic, Optical and Magnetic Materials, Blueshift, Laser linewidth, Condensed Matter::Materials Science, strain, Quantum dot, Materials Chemistry, Optoelectronics, Charge carrier, interdiffusion, Electrical and Electronic Engineering, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], business
Abstract

International audience; The effect of the lattice-mismatch strain and of the charge carrier confinement profile, on the optical properties of thermally annealed self-assembled InxGa1-xAs/GaAs quantum dots (QDs), is theoretically analyzed by using a recently developed 40-band k.p model. First, to evaluate the composition and size of QDs as a function of thermal annealing conditions, we model the In/Ga interdiffusion by a Fickian diffusion. Second, we investigate the decrease of the strain effects on the carrier confinement potentials with annealing by solving the Schrodinger equation separately for electrons and holes. It is clearly found that the strain strongly modifies the QD potential profile, leading to a different electron and hole energy distribution. Finally, we carry on a comparison between theoretical calculations and photoluminescence (PL) experimental results performed in thermal annealed samples. A good agreement is obtained for the energy blueshift and the linewidth narrowing of the PL spectra measured on annealed QD ensemble. These results prove the relevance of the present approach to describe the optoelectronic properties of the nanostructures through the post-growth thermal annealing treatment.

Published
2014
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