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1. Copper-doped lanthanum manganite La0.65Ce0.05Sr0.3Mn1−xCuxO3 influence on structural, magnetic and magnetocaloric effects

Author

E.K. Hlil, A. Fouzri, Ma. Oumezzine, R. Bellouz, M. Chebaane, Laboratoire Physico-Chimie des Matériaux [Monastir], Faculté des Sciences de Monastir (FSM), Université de Monastir - University of Monastir (UM)-Université de Monastir - University of Monastir (UM), Magnétisme et Supraconductivité (MagSup ), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), and Laboratoire de Micro-optoélectronique et Nanostructures [Monastir]

Subjects
010302 applied physics, Phase transition, Materials science, Rietveld refinement, Magnetism, General Chemical Engineering, Analytical chemistry, 02 engineering and technology, General Chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Paramagnetism, Magnetization, chemistry.chemical_compound, Ferromagnetism, Lanthanum manganite, chemistry, 0103 physical sciences, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Curie temperature, 0210 nano-technology, ComputingMilieux_MISCELLANEOUS
Abstract

Bulk nanocrystalline samples of La0.65Ce0.05Sr0.3Mn1−xCuxO3 (0 ≤ x ≤ 0.15) manganites are prepared by the sol–gel based Pechini method. The effect of the substitution for Mn with Cu upon the structural and magnetic properties has been investigated by means of X-ray diffraction (XRD), Raman spectroscopy and dc magnetization measurements. The structural parameters obtained using Rietveld refinement of XRD data showed perovskite structures with rhombohedral (Rc) symmetry without any detectable impurity phase. Raman spectra at room temperature reveal a gradual change in phonon modes with increasing copper concentration. The analysis of the crystallographic data suggested a strong correlation between structure and magnetism, for instance a relationship between a distortion of the MnO6 octahedron and the reduction in the Curie temperature, Tc. A paramagnetic to ferromagnetic phase transition at TC is observed. The experimental results confirm that Mn-site substitution with Cu destroys the Mn3+–O2−–Mn4+ bridges and weakens the double exchange (DE) interaction between Mn3+ and Mn4+ ions, which shows an obvious suppression of the FM interaction in the La0.65Ce0.05Sr0.3Mn1−xCuxO3 matrix. The maximum magnetic entropy change −ΔSmaxM is found to decrease with increasing Cu content from 4.43 J kg−1 K−1 for x = 0 to 3.03 J kg−1 K−1 for x = 0.15 upon a 5 T applied field change.

Published
2018

2. Investigation of the localization phenomenon in quaternary BInGaAs/GaAs for optoelectronic applications

Author

Faouzi Saidi, Tarek Hidouri, R. Hamila, Ibtissem Fraj, Laurent Auvray, Hassen Maaref, Philippe Rodriguez, Laboratoire de micro-optoelectronique et nanostructures, Université de Monastir - University of Monastir (UM), Laboratoire de Micro-optoélectronique et Nanostructures [Monastir], Faculté des Sciences de Monastir (FSM), Université de Monastir - University of Monastir (UM)-Université de Monastir - University of Monastir (UM), Laboratoire des Multimatériaux et Interfaces (LMI), Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
010302 applied physics, Diffraction, Photoluminescence, Materials science, business.industry, Band gap, Exciton, 02 engineering and technology, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, [SPI.MAT]Engineering Sciences [physics]/Materials, Condensed Matter::Materials Science, Full width at half maximum, 0103 physical sciences, [SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic, Optoelectronics, General Materials Science, Metalorganic vapour phase epitaxy, Electrical and Electronic Engineering, 0210 nano-technology, business, Spectroscopy, Quantum well, ComputingMilieux_MISCELLANEOUS
Abstract

In this paper, single quantum well (SQW) structure of BxInyGa1-x-yAs/GaAs lattice-matched to GaAs has been grown by metal organic vapor phase epitaxy (MOVPE). The sample was characterized morphologically and structurally using the atomic force microscopy AFM, transmission electron microscopy TEM and high resolution X-ray diffraction HRXRD measurements. The optical study was investigated by photoluminescence (PL) spectroscopy as a function of temperature. The PL peak energy, the full width at half maximum (FWHM) and the PL intensity, versus temperature, exhibit anomalous behaviors such as S-shaped and N-shaped. They were attributed to the creation of a fluctuation potential in the band edge of the host material from the non-uniform distribution of boron atoms in the structure induced exciton localization. We investigate the localization phenomenon by excitation density variation. Then, a quasi-steady state rate-equation model for temperature dependent luminescence spectra of localized-state material system (LSE) was presented to quantitatively reinterpret the band gap emission process. The novel analytical models, compared with the classical ones, were used to fit the PL peak energy evolution. Good agreement between experimental and theoretical results has been observed using the modified Passler model. Modeling results will be discussed based on specified parameters. These results can improve the fundamental properties of quaternary based on light-emitting and optoelectronic devices.

Published
2017

3. Carrier dynamics of strain-engineered InAs quantum dots with (In)GaAs surrounding material

Author

Nicolas Chauvin, Bouraoui Ilahi, Catherine Bru-Chevallier, L. Sfaxi, Olfa Nasr, M.H. Hadj Alouane, Hassen Maaref, INL - Spectroscopies et Nanomatériaux (INL - S&N), Institut des Nanotechnologies de Lyon (INL), École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-École Centrale de Lyon (ECL), Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Micro-optoélectronique et Nanostructures [Monastir], Faculté des Sciences de Monastir (FSM), and Université de Monastir - University of Monastir (UM)-Université de Monastir - University of Monastir (UM)

Subjects
Materials science, Nanostructure, Photoluminescence, Nanotechnology, 02 engineering and technology, Epitaxy, 01 natural sciences, [SPI.MAT]Engineering Sciences [physics]/Materials, Optics, 0103 physical sciences, [SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics, ComputingMilieux_MISCELLANEOUS, 010302 applied physics, [PHYS]Physics [physics], [PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics], Strain (chemistry), business.industry, Carrier lifetime, 021001 nanoscience & nanotechnology, Atomic and Molecular Physics, and Optics, Electronic, Optical and Magnetic Materials, Quantum dot, [SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic, Optoelectronics, 0210 nano-technology, business, Luminescence, Excitation
Abstract

International audience; no abstract

Published
2017

4. Optical investigation of InAs quantum dashes grown on InP(001) vicinal substrate

Author

M. Bouslama, Hassen Maaref, M.H. Hadj Alouane, Nicolas Chauvin, F. Besahraoui, Z. Lounis, Faouzi Saidi, Michel Gendry, M. Ghaffour, L. Bouzaiene, Inl, Laboratoire INL UMR5270, Laboratoire Matériaux (LABMAT), Ecole Nationale Polytechnique d’Oran (ENPO), Laboratoire de Micro-optoélectronique et Nanostructures [Monastir], Faculté des Sciences de Monastir (FSM), Université de Monastir - University of Monastir (UM)-Université de Monastir - University of Monastir (UM), INL - Spectroscopies et Nanomatériaux (INL - S&N), Institut des Nanotechnologies de Lyon (INL), École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-École Centrale de Lyon (ECL), Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), and INL - Hétéroepitaxie et Nanostructures (INL - H&N)

Subjects
Photoluminescence, Materials science, [SPI.OPTI] Engineering Sciences [physics]/Optics / Photonic, [SPI] Engineering Sciences [physics], Infrared, [SPI.NANO] Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics, Substrate (electronics), [SPI.MAT] Engineering Sciences [physics]/Materials, 7. Clean energy, [SPI.MAT]Engineering Sciences [physics]/Materials, law.invention, [SPI]Engineering Sciences [physics], law, General Materials Science, [SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics, Electrical and Electronic Engineering, Spectroscopy, ComputingMilieux_MISCELLANEOUS, business.industry, Condensed Matter Physics, Laser, Quantum dot, [SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic, Optoelectronics, business, Vicinal, Molecular beam epitaxy
Abstract

We investigate with photoluminescence (PL) measurements the optoelectronic properties of self-organized InAs quantum dots (QDs) grown on nominal InP(0 0 1) substrate. InAs/InP(0 0 1) QDs are grown by Molecular Beam Epitaxy (MBE) method with optimized conditions in Stranski-Krastanov regime. A lateral coupling behavior was shown by photoluminescence spectroscopy. This phenomena is considered as a degradation source of the optoelectronic properties of InAs/InP(0 0 1) QDs used in lasers applications. In order to overcome this disadvantage behavior, we have studied the optical properties of InAs quantum islands (QIs) grown on vicinal InP(0 0 1) with 2° off miscut angle toward the [1 1 0] direction. From Polarized Photoluminescence (PPL) measurements, we have deduced that InAs quantum nanostructures have quantum dashes (QDas) form elongated in [1] , [2] , [3] , [4] , [5] , [6] , [7] , [8] , [9] , [10] direction. From excitation density PL measurements, we have evidenced that the different observed PL peaks are attributed to the emission of InAs QDas of different size. The lateral coupling behavior is completely eliminated in the case of this sample. The temperature-dependent PL measurements show a good thermal stability and an emission wavelength at room temperature around 1.55 μm of the vicinal sample. All these properties prove that this sample possess favorable characteristics for microlasers based devices functioning at room temperature and for optical telecommunication with long range weapon. The broad emission range observed at 300 K of the vicinal sample gives the possibility to use it as an active zone in solar cells and in infrared photodectectors of high optical gain and excellent sensitivity on a wide energy range.

Published
2014

5. LSE investigation of the thermal effect on band gap energy and thermodynamic parameters of BInGaAs/GaAs Single Quantum Well

Author

Tarek Hidouri, Ph. Rodriguez, Laurent Auvray, Faouzi Saidi, Hassen Maaref, Laboratoire de Micro-optoélectronique et Nanostructures [Monastir], Faculté des Sciences de Monastir (FSM), Université de Monastir - University of Monastir (UM)-Université de Monastir - University of Monastir (UM), Laboratoire des Multimatériaux et Interfaces (LMI), Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Photoluminescence, Band gap, 02 engineering and technology, Chemical vapor deposition, 01 natural sciences, 7. Clean energy, [SPI.MAT]Engineering Sciences [physics]/Materials, Inorganic Chemistry, Delocalized electron, 0103 physical sciences, Thermal, Metalorganic vapour phase epitaxy, Electrical and Electronic Engineering, Physical and Theoretical Chemistry, Spectroscopy, Quantum well, ComputingMilieux_MISCELLANEOUS, 010302 applied physics, Condensed matter physics, Chemistry, Organic Chemistry, Atmospheric temperature range, 021001 nanoscience & nanotechnology, Atomic and Molecular Physics, and Optics, Electronic, Optical and Magnetic Materials, [SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic, 0210 nano-technology
Abstract

In this paper, we report on the experimental and theoretical study of BInGaAs/GaAs Single Quantum Well elaborated by Metal Organic Chemical Vapor Deposition (MOCVD). We carried out the photoluminescence (PL) peak energy temperature-dependence over a temperature range of 10–300 K. It shows the S-shaped behavior as a result of a competition process between localized and delocalized states. We simulate the peak evolution by the empirical model and modified models. The first one is limited at high PL temperature. For the second one, a correction due to the thermal redistribution based on the Localized State Ensemble model (LSE). The new fit gives a good agreement between theoretical and experimental data in the entire temperature range. Furthermore, we have investigated an approximate analytical expressions and interpretation for the entropy and enthalpy of formation of electron-hole pairs in quaternary BInGaAs/GaAs SQW.

Published
2016

6. Power density and temperature dependent multi-excited states in InAs/GaAs quantum dots

Author

Hassen Maaref, Catherine Bru-Chevallier, L. Bouzaiene, L. Sfaxi, M. Baira, INL - Spectroscopies et Nanomatériaux (INL - S&N), Institut des Nanotechnologies de Lyon (INL), École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-École Centrale de Lyon (ECL), Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Micro-optoélectronique et Nanostructures [Monastir], Faculté des Sciences de Monastir (FSM), and Université de Monastir - University of Monastir (UM)-Université de Monastir - University of Monastir (UM)

Subjects
010302 applied physics, Photoluminescence, Materials science, Exciton, Bioengineering, 02 engineering and technology, General Chemistry, Atmospheric temperature range, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, 7. Clean energy, Atomic and Molecular Physics, and Optics, Full width at half maximum, Quantum dot, Modeling and Simulation, Excited state, 0103 physical sciences, General Materials Science, [SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics, Atomic physics, 0210 nano-technology, ComputingMilieux_MISCELLANEOUS, Power density, Molecular beam epitaxy
Abstract

Self-assembled InAs/GaAs (001) quantum dots (QDs) were grown by molecular beam epitaxy using ultra low-growth rate. A typical dot diameter of around 28 ± 2 nm and a typical height of 5 ± 1 nm are observed based on atomic force microscopy image. The photoluminescence (PL) spectra, their power and temperature dependences have been studied for ground (GS) and three excited states (1–3ES) in InAs QDs. By changing the excitation power density, we can significantly influence the distribution of excitons within the QD ensemble. The PL peak energy positions of GS and ES emissions bands depend on an excitation light power. With increasing excitation power, the GS emission energy was red-shifted, while the 1–3ES emission energies were blue-shifted. It is found that the full width at half maximum of the PL spectra has unusual relationship with increasing temperature from 9 to 300 K. The temperature dependence of QD PL spectra shown the existence of two stages of PL thermal quenching and two distinct activation energies corresponding to the temperature ranges I (9–100 K) and II (100–300 K).

Published
2010

7. Growth study of thin indium nitride layers on InP (100) by Auger electron spectroscopy and photoluminescence

Author

F. Saidi, Hassen Maaref, F. Hassen, Christine Robert-Goumet, Bernard Gruzza, S. Ben Khalifa, Luc Bideux, Institut Pascal (IP), SIGMA Clermont (SIGMA Clermont)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020]), Institut Lavoisier de Versailles (ILV), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des sciences et matériaux pour l'électronique et d'automatique (LASMEA), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Micro-optoélectronique et Nanostructures [Monastir], Faculté des Sciences de Monastir (FSM), Université de Monastir - University of Monastir (UM)-Université de Monastir - University of Monastir (UM), and SIGMA Clermont (SIGMA Clermont)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS)

Subjects
010302 applied physics, Auger electron spectroscopy, Glow discharge, Photoluminescence, Indium nitride, Chemistry, Band gap, Exciton, Analytical chemistry, 02 engineering and technology, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Inorganic Chemistry, chemistry.chemical_compound, 0103 physical sciences, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Materials Chemistry, Indium phosphide, [SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics, 0210 nano-technology, Spectroscopy, ComputingMilieux_MISCELLANEOUS
Abstract

This article investigates the growth of InN layers on (1 0 0) InP in ultra-high vacuum using a glow discharge source (GDS). Auger electron spectroscopy (AES) was used to understand the different steps of the nitridation process with the analysis of In-MNN, N-KLL and P-LMM transitions. A modeling of Auger signals using a stacked layers model allows us to confirm that four monolayers of indium nitride are created on (1 0 0) InP. InN layers grown on (1 0 0) InP were studied optically by photoluminescence (PL) spectroscopy versus the excitation power and the sample temperature (10–300 K). Results show broad spectral band energy close to the lowest reported InN bandgap. The temperature dependence of the PL peak energy showed a S-shaped behavior (decrease–increase–decrease). The results suggest that the InN-related emission is significantly affected by the change in carrier dynamics with increasing temperature: the effect can be due to the large exciton localization effects.

Published
2009

8. Study of porous III–V semiconductors by electron spectroscopies (AES and XPS) and optical spectroscopy (PL): Effect of ionic bombardment and nitridation process

Author

Georges Bremond, R. Hamila, Ridha Mghaieth, Mokhtar Hjiri, S. Ben Khalifa, F. Saidi, F. Hassen, Guillaume Monier, Bernard Gruzza, Luc Bideux, Lotfi Beji, Christine Robert-Goumet, Hassen Maaref, Institut Pascal (IP), SIGMA Clermont (SIGMA Clermont)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS), Laboratoire des sciences et matériaux pour l'électronique et d'automatique (LASMEA), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Centre National de la Recherche Scientifique (CNRS), Institut Lavoisier de Versailles (ILV), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Department of Electrical Engineering, College of Engineering, Qatar University, PO BOX 2713, Doha, Qatar, Qatar University, Laboratoire de Micro-optoélectronique et Nanostructures [Monastir], Faculté des Sciences de Monastir (FSM), Université de Monastir - University of Monastir (UM)-Université de Monastir - University of Monastir (UM), Laboratoire de physique de la matière (LPM), Institut National des Sciences Appliquées de Lyon (INSA Lyon), and Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
010302 applied physics, Glow discharge, Photoluminescence, Materials science, business.industry, Analytical chemistry, 02 engineering and technology, Surfaces and Interfaces, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Electron spectroscopy, Surfaces, Coatings and Films, Semiconductor, X-ray photoelectron spectroscopy, 0103 physical sciences, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Materials Chemistry, [SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics, 0210 nano-technology, business, Porous medium, Spectroscopy, Luminescence, ComputingMilieux_MISCELLANEOUS
Abstract

Electron spectroscopy (AES and XPS) and photoluminescence analysis (PL) were used to study porous layers elaborated by electrochemical etching of p-GaAs and n-InP substrates. Surface characterizations have been performed on the as received porous substrates, ions bombarded and nitridated porous layers. Porous surfaces of GaAs(1 0 0) and InP(1 0 0) have been compared after different treatments: Argon ion bombardment and nitridation with a glow discharge source (GDS) in UHV. These processes have been followed by Auger measurements (AES). The effects of the bombardment and the nitridation of porous InP were studied. The PL investigations of the porous GaAs layer show visible and infrared photoluminescence bands. Quantum confinement in the nanocrystallites of GaAs formed by electrochemical etching can explain the luminescence of the porous GaAs layers.

Published
2007

9. Optical properties of 1.3 μm room temperature emitting InAs quantum dots covered by In0.4Ga0.6As/GaAs hetero-capping layer

Author

A. Jbeli, Hassen Maaref, Gérard Guillot, Xavier Marie, Bassem Salem, Bouraoui Ilahi, L. Sfaxi, F. Hassen, Laboratoire de Micro-optoélectronique et Nanostructures [Monastir], Faculté des Sciences de Monastir (FSM), Université de Monastir - University of Monastir (UM)-Université de Monastir - University of Monastir (UM), Laboratoire des technologies de la microélectronique (LTM), Université Joseph Fourier - Grenoble 1 (UJF)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de physique de la matière (LPM), Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), and Institut National des Sciences Appliquées (INSA)

Subjects
010302 applied physics, Photoluminescence, Condensed matter physics, Chemistry, 02 engineering and technology, General Chemistry, Atmospheric temperature range, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, 021001 nanoscience & nanotechnology, 01 natural sciences, 7. Clean energy, Molecular physics, [SPI]Engineering Sciences [physics], Condensed Matter::Materials Science, Quantum dot, Excited state, 0103 physical sciences, General Materials Science, Photoluminescence excitation, 0210 nano-technology, Ground state, ComputingMilieux_MISCELLANEOUS, Quantum well, Molecular beam epitaxy
Abstract

Room temperature 1.3 μm emitting InAs quantum dots (QDs) covered by an In0.4Ga0.6As/GaAs strain reducing layer (SRL) have been fabricated by solid source molecular beam epitaxy (SSMBE) using the Stranski–Krastanov growth mode. The sample used has been investigated by temperature and excitation power dependent photoluminescence (PL), photoluminescence excitation (PLE), and time resolved photoluminescence (TRPL) experiments. Three emission peaks are apparent in the low temperature PL spectrum. We have found, through PLE measurement, a single quantum dot ground state and the corresponding first excited state with relatively large energy spacing. This attribute has been confirmed by TRPL measurements which allow comparison of the dynamics of the ground state with that of the excited states. Optical transitions related to the InGaAs quantum well have been also identified. Over the whole temperature range, the PL intensity is found to exhibit an anomalous increase with increasing temperatures up to 100 K and then followed by a drop by three orders of magnitude. Carrier’s activation energy out of the quantum dots is found to be close to the energy difference between each two subsequent transition energies.

Published
2005

10. Optical investigation of GaAs1−xNx/GaAs heterostructure properties

Author

F. Hassen, Yves Monteil, H. Dumont, Laurent Auvray, Faouzi Saidi, Hassen Maaref, Laboratoire de Micro-optoélectronique et Nanostructures [Monastir], Faculté des Sciences de Monastir (FSM), Université de Monastir - University of Monastir (UM)-Université de Monastir - University of Monastir (UM), Laboratoire des Multimatériaux et Interfaces (LMI), Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS]Physics [physics], 010302 applied physics, Photoluminescence, Condensed matter physics, Chemistry, Exciton, Heterojunction, 02 engineering and technology, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Epitaxy, 01 natural sciences, Electronic, Optical and Magnetic Materials, Blueshift, Phase (matter), 0103 physical sciences, Metalorganic vapour phase epitaxy, 0210 nano-technology, ComputingMilieux_MISCELLANEOUS, Quantum well
Abstract

We have investigated, by photoluminescence (PL), the optical properties of GaAs1−xNx/GaAs epilayers and GaAs1−xNx/GaAs quantum well (QW) structures grown by metal organic vapor phase epitaxy (MOVPE) on (001)-oriented GaAs substrates. Different behaviors have been observed for the bulk epilayer and for the QW structures, respectively: (i) a blue shift of the PL bands in both kinds of structures when increasing the excitation density, (ii) an S-shaped PL peak energy versus temperature dependence has been observed for the GaAsN epilayer but a usual behavior is obtained for the QWs. Based in these experimental results, we have suggested that the carrier recombination mechanisms in the epilayer and in the quantum well structure are different. An enhanced exciton-localization-like mode for the epilayer is observed. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Published
2004

11. Spacer layer thickness effects on the photoluminescence properties of InAs/GaAs quantum dot superlattices

Author

Hassen Maaref, Georges Bremond, Olivier Marty, F. Hassen, Bouraoui Ilahi, L. Bouzaiene, Bassem Salem, L. Sfaxi, Laboratoire de Micro-optoélectronique et Nanostructures [Monastir], Faculté des Sciences de Monastir (FSM), Université de Monastir - University of Monastir (UM)-Université de Monastir - University of Monastir (UM), Laboratoire de micro-optoelectronique et nanostructures, Université de Monastir - University of Monastir (UM), Laboratoire des technologies de la microélectronique (LTM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), and Université Joseph Fourier - Grenoble 1 (UJF)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
010302 applied physics, Photoluminescence, Condensed matter physics, Chemistry, Superlattice, 02 engineering and technology, Atmospheric temperature range, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Electronic, Optical and Magnetic Materials, Transmission electron microscopy, Quantum dot, 0103 physical sciences, Monolayer, [SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics, Dislocation, 0210 nano-technology, ComputingMilieux_MISCELLANEOUS, Molecular beam epitaxy
Abstract

68.37.Lp, 78.55.Cr, 78.67.Hc, 78.67.Pt, 79.40.+z InAs/GaAs vertically stacked self-assembled quantum dot (QD) structures with different GaAs spacer layer thicknesses are grown by solid source molecular beam epitaxy (SSMBE) and investigated by trans-mission electron microscopy (TEM) and photoluminescence (PL) spectroscopy. An increase in the polari-zation anisotropy is observed when the spacer layer thickness decreases. For a 10 monolayer (ML) thick inter-dots GaAs spacer, the TEM image shows an increase in the QD size when moving to the upper layer accompanied by the generation of dislocations. Consequently, the corresponding temperature-dependant PL properties are found to exhibit an unusual behaviour. The main PL peak is quenched at a temperature around 190 K giving rise to a broad background correlated with the formation of a miniband in the growth direction due to the strong interlayer coupling. For a thicker GaAs spacer layer (30 ML), multilayer QDs align vertically in stacks with no apparent structural defects. Over the whole temperature range, the exci-tonic band energies are governed by the Varshni empirical relation using InAs bulk parameters and the PL line width shows a slight monotonic increase. For a thinner GaAs interlayer, the thermal activation ener-gies of the carrier emission out of the quantum dots are found to be considerably small (about 25 meV) due to the existence of defects. By combining these structural and optical results, we can conclude that a thinner GaAs spacer has a poorer quality.

Published
2003

12. Carriers' localization and thermal redistribution in post growth voluntarily tuned quantum dashes' size/composition distribution

Author

Hadj Alouane M, H., Helali, A., Morris, D., Maaref, H., Aimez, Vincent, Salem, B., Gendry, Michel, Ilahi, B., Laboratoire de Micro-optoélectronique et Nanostructures [Monastir], Faculté des Sciences de Monastir (FSM), Université de Monastir - University of Monastir (UM)-Université de Monastir - University of Monastir (UM), INL - Spectroscopies et Nanomatériaux (INL - S&N), Institut des Nanotechnologies de Lyon (INL), Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-École Centrale de Lyon (ECL), Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-École supérieure de Chimie Physique Electronique de Lyon (CPE), Institut Interdisciplinaire d'Innovation Technologique [Sherbrooke] (3IT), Université de Sherbrooke (UdeS), Laboratoire des technologies de la microélectronique (LTM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), INL - Hétéroepitaxie et Nanostructures (INL - H&N), École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-École Supérieure de Chimie Physique Électronique de Lyon (CPE)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-École Centrale de Lyon (ECL), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Université Joseph Fourier - Grenoble 1 (UJF)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), and Inl, Laboratoire INL UMR5270

Subjects
[SPI]Engineering Sciences [physics], [SPI.OPTI] Engineering Sciences [physics]/Optics / Photonic, [SPI] Engineering Sciences [physics], [SPI.NANO] Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics, [SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic, [SPI.MAT] Engineering Sciences [physics]/Materials, [SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics, ComputingMilieux_MISCELLANEOUS, [SPI.MAT]Engineering Sciences [physics]/Materials
Abstract

International audience; no abstract

Published
2014

13. Improved photovoltaic performance of silicon nanowires/conjugated polymer hybrid solar cells

Author

Chehata, N., taief, L., Ilahi, A., Salem, B., Bouazizi, B., Maaref, A., Baron, T., Gentile, P., Faculté des Sciences de Monastir (FSM), Université de Monastir - University of Monastir (UM), Laboratoire des technologies de la microélectronique (LTM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Silicon Nanoelectronics Photonics and Structures (SiNaps), PHotonique, ELectronique et Ingénierie QuantiqueS (PHELIQS), Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut Polytechnique de Bordeaux (Bordeaux INP), Laboratoire d'automatique de Caen (LAC), École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Normandie Université (NU)-Université de Caen Normandie (UNICAEN), Normandie Université (NU), Laboratoire de Micro-optoélectronique et Nanostructures [Monastir], Université de Monastir - University of Monastir (UM)-Université de Monastir - University of Monastir (UM), Laboratoire de Physique et Chimie des Interfaces [Monastir] (LPCI), Ingénierie des Matériaux Polymères (IMP), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Jean Monnet [Saint-Étienne] (UJM)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon, Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Equipe Automatique - Laboratoire GREYC - UMR6072, Groupe de Recherche en Informatique, Image et Instrumentation de Caen (GREYC), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS), Université Joseph Fourier - Grenoble 1 (UJF)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), and Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Jean Monnet - Saint-Étienne (UJM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Photoluminescence, Materials science, Nanowire, Photovoltaic effect, Hybrid solar cells, Conjugated system, 7. Clean energy, Si nanowires, Materials Chemistry, Polymer, ComputingMilieux_MISCELLANEOUS, chemistry.chemical_classification, [PHYS]Physics [physics], Nanocomposite, business.industry, Mechanical Engineering, Photovoltaic system, Metals and Alloys, Hybrid solar cell, [CHIM.MATE]Chemical Sciences/Material chemistry, Condensed Matter Physics, Electronic, Optical and Magnetic Materials, [CHIM.POLY]Chemical Sciences/Polymers, chemistry, Mechanics of Materials, Optoelectronics, business, Photoluminescence quenching
Abstract

International audience; In this study, we investigate the effect of incorporation of Si nanowires (SiNWs) on the organic/inorganic hybrid nanocomposites based on poly [2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylene vinylene] (MEH-PPV) and SiNWs. A huge potential for SiNWs for an amelioration of optical properties of investigated structures was shown, and particularly a more efficient charge transfer was guaranteed. The impact of SiNWs incorporation on photoluminescence properties of polymer:Si nanowires nanocomposites have been correlated with morphological characteristics. MEH-PPV:SiNWs (1:2) is the optimum composition where the device performance displays a Jsc of 0.328 μA/cm2, a Voc of 0.680 V and FF of 38%.

Published
2014

14. Piezoelectric effect in InAs/InP quantum rod nanowires grown on silicon substrate

Author

Catherine Bru-Chevallier, Nicolas Chauvin, Gilles Patriarche, H. Khmissi, Roman Anufriev, K. Naji, Michel Gendry, INL - Spectroscopies et Nanomatériaux (INL - S&N), Institut des Nanotechnologies de Lyon (INL), École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-École Centrale de Lyon (ECL), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Micro-optoélectronique et Nanostructures [Monastir], Faculté des Sciences de Monastir (FSM), Université de Monastir - University of Monastir (UM)-Université de Monastir - University of Monastir (UM), INL - Hétéroepitaxie et Nanostructures (INL - H&N), Laboratoire de photonique et de nanostructures (LPN), Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-École Centrale de Lyon (ECL), Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), and Université de Lyon-École supérieure de Chimie Physique Electronique de Lyon (CPE)

Subjects
Materials science, Physics and Astronomy (miscellaneous), Condensed matter physics, Condensed Matter::Other, Quantum-confined Stark effect, Nanogenerator, Nanowire, Physics::Optics, Heterojunction, Substrate (electronics), Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, Piezoelectricity, [SPI.MAT]Engineering Sciences [physics]/Materials, Condensed Matter::Materials Science, symbols.namesake, [SPI]Engineering Sciences [physics], Stark effect, symbols, [SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic, [SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics, ComputingMilieux_MISCELLANEOUS, Wurtzite crystal structure
Abstract

We report on the evidence of a strain-induced piezoelectric field in wurtzite InAs/InP quantum rod nanowires. This electric field, caused by the lattice mismatch between InAs and InP, results in the quantum confined Stark effect and, as a consequence, affects the optical properties of the nanowire heterostructure. It is shown that the piezoelectric field can be screened by photogenerated carriers or removed by increasing temperature. Moreover, a dependence of the piezoelectric field on the quantum rod diameter is observed in agreement with simulations of wurtzite InAs/InP quantum rod nanowire heterostructures.

Published
2014

15. Fermi edge singularity evidence from photoluminescence spectroscopy of AlGaAs/InGaAs/GaAs pseudomorphic HEMTs grown on (311)A GaAs substrates

Author

S., REKAYA, L., SFAXI, BRU-CHEVALLIER, C., H., MAAREF, BRU CHEVALLIER, Catherine, Laboratoire de Micro-optoélectronique et Nanostructures [Monastir], Faculté des Sciences de Monastir (FSM), Université de Monastir - University of Monastir (UM)-Université de Monastir - University of Monastir (UM), INL - Spectroscopies et Nanomatériaux (INL - S&N), Institut des Nanotechnologies de Lyon (INL), École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-École Centrale de Lyon (ECL), and Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SPI]Engineering Sciences [physics], [SPI] Engineering Sciences [physics], [SPI.NANO] Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics, [SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2011

16. Temperature dependence of optical properties of InAs/GaAs self-organized quantum dots

Author

Hassen Maaref, Catherine Bru-Chevallier, Olivier Marty, L. Sfaxi, M. Baira, L. Bouzaiene, Laboratoire de Micro-optoélectronique et Nanostructures [Monastir], Faculté des Sciences de Monastir (FSM), Université de Monastir - University of Monastir (UM)-Université de Monastir - University of Monastir (UM), Laboratoire d'Electronique, Nanotechnologies, Capteurs (LENAC), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon, INL - Spectroscopies et Nanomatériaux (INL - S&N), Institut des Nanotechnologies de Lyon (INL), École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-École Centrale de Lyon (ECL), and Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Photoluminescence, Materials science, Physics::Optics, General Physics and Astronomy, 02 engineering and technology, Electron, 01 natural sciences, 7. Clean energy, Spectral line, Gallium arsenide, Condensed Matter::Materials Science, chemistry.chemical_compound, [SPI]Engineering Sciences [physics], Effective mass (solid-state physics), 0103 physical sciences, Electronic band structure, ComputingMilieux_MISCELLANEOUS, 010302 applied physics, Condensed matter physics, Condensed Matter::Other, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, 021001 nanoscience & nanotechnology, chemistry, Quantum dot, [SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic, 0210 nano-technology, Molecular beam epitaxy
Abstract

Self-organized InAs/GaAs quantum dots (QDs) were grown by molecular beam epitaxy. The photoluminescence, its power, and temperature dependences have been studied for the ensembles of InAs QDs embedded in GaAs matrix to investigate the interband transition energies. Theoretical calculations of confined electron (heavy-hole) energy in the InAs/GaAs QDs have been performed by means of effective mass approximation, taking into account strain effects. The shape of the InAs QDs was modeled to be a convex-plane lens. The calculated interband transition energies were compared with the results of the photoluminescence spectra. The calculated interband transition energy from the ground electronic subband to the ground heavy-hole state was in reasonable agreement with the transition energy obtained by the photoluminescence measurement.

Published
2009

17. Clustering effects in optical properties of BGaAs/GaAs epilayers

Author

Hassen Maaref, Yves Monteil, R. Hamila, Faouzi Saidi, Laurent Auvray, A. Fouzri, Laboratoire de Micro-optoélectronique et Nanostructures [Monastir], Faculté des Sciences de Monastir (FSM), Université de Monastir - University of Monastir (UM)-Université de Monastir - University of Monastir (UM), Laboratoire des Multimatériaux et Interfaces (LMI), Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
010302 applied physics, Quenching, [PHYS]Physics [physics], Photoluminescence, Chemistry, Doping, Biophysics, Analytical chemistry, chemistry.chemical_element, 02 engineering and technology, General Chemistry, Chemical vapor deposition, Activation energy, Atmospheric temperature range, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Biochemistry, Atomic and Molecular Physics, and Optics, 0103 physical sciences, Metalorganic vapour phase epitaxy, 0210 nano-technology, Boron, ComputingMilieux_MISCELLANEOUS
Abstract

We report on the further investigation of the effect of boron incorporation on GaAs grown at 580 °C temperature on GaAs (0 0 1) substrate by metal organic chemical vapor deposition (MOCVD). High-resolution X-ray diffraction (HRXRD) has been used to determine the lattice mismatch and to estimate the boron concentration. Temperature-dependent photoluminescence has been carried out to investigate B x Ga 1− x As/GaAs epilayers with varied boron composition ( x =1.64% and 3.04%). Low temperature (10 K) PL study has shown an asymmetric and broad PL band around 1.3 eV of the emission energies with a decrease of the PL intensity with increasing boron composition. The evolution of the emission energies with temperature can be described by Varshni law for the high temperature range ( T ⩾120 and 80 K) for boron composition x =1.64% and 3.04%, respectively, while a relative discrepancy has been found to occur at low temperature. Moreover, depending on the temperature range, the PL intensity quenching is found to be thermally ensured by three activation energies. These results are attributed to the localized states induced by the non-uniform insertion of boron and the clustering of the boron atom in BGaAs bulk.

Published
2009

18. Morphology and optical properties of p-type porous GaAs(100) layers made by electrochemical etching

Author

Georges Bremond, Mokhtar Hjiri, F. Saidi, Bernard Gruzza, Lotfi Beji, S. Ben Khalifa, Luc Bideux, Christine Robert-Goumet, Hassen Maaref, Institut Pascal (IP), SIGMA Clermont (SIGMA Clermont)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020]), Laboratoire des sciences et matériaux pour l'électronique et d'automatique (LASMEA), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de physique de la matière (LPM), Institut National des Sciences Appliquées de Lyon (INSA Lyon), Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Institut Lavoisier de Versailles (ILV), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Micro-optoélectronique et Nanostructures [Monastir], Faculté des Sciences de Monastir (FSM), Université de Monastir - University of Monastir (UM)-Université de Monastir - University of Monastir (UM), SIGMA Clermont (SIGMA Clermont)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS), and Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Photoluminescence, Biophysics, Oxide, Analytical chemistry, 02 engineering and technology, 01 natural sciences, Biochemistry, chemistry.chemical_compound, X-ray photoelectron spectroscopy, 0103 physical sciences, [SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics, ComputingMilieux_MISCELLANEOUS, 010302 applied physics, General Chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Microstructure, Atomic and Molecular Physics, and Optics, chemistry, Nanocrystal, Quantum dot, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Crystallite, 0210 nano-technology, Porous medium
Abstract

Porous GaAs layers were formed by electrochemical etching of p-type GaAs(1 0 0) substrates in HF solution. A surface characterization has been performed on p-type GaAs samples using X-ray photoelectron spectroscopy (XPS) technique in order to get information about the chemical composition, particularly on the surface contamination. According to the XPS spectra, the oxide layer on as-received porous GaAs substrates contains As2O3, As2O5 and Ga2O3. Large amount of oxygen is present at the surface before the surface cleaning. Compared to untreated GaAs surface, room temperature photoluminescence (PL) investigations of the porous layers reveal the presence of two PL bands: a PL peak at ∼871 nm and a “visible” PL peak at ∼650–680 nm. Both peak wavelengths and intensities varied from sample to sample depending on the treatment that the samples have undergone. The short PL wavelength at 650–680 nm of the porous layers is attributed to quantum confinement effects in GaAs nano-crystallites. The surface morphology of porous GaAs has been studied using atomic force microscopy (AFM). Nano-sized crystallites were observed on the porous GaAs surface. An estimation of the mean size of the GaAs nano-crystals obtained from effective mass theory and based on PL data was close to the lowest value obtained from the AFM results.

Published
2008

19. Optical investigation of phosphorous-ion-implantation induced InAs/GaAs quantum dots' intermixing

Author

Bouraoui Ilahi, Denis Morris, L. Sfaxi, Bassem Salem, Z. Zaâboub, Vincent Aimez, Hassen Maaref, Laboratoire de Micro-optoélectronique et Nanostructures [Monastir], Faculté des Sciences de Monastir (FSM), Université de Monastir - University of Monastir (UM)-Université de Monastir - University of Monastir (UM), Laboratoire de micro-optoelectronique et nanostructures, Université de Monastir - University of Monastir (UM), Laboratoire des technologies de la microélectronique (LTM), Université Joseph Fourier - Grenoble 1 (UJF)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Université de Sherbrooke (UdeS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)

Subjects
010302 applied physics, Physics, Low temperature photoluminescence, Photoluminescence, Band gap, business.industry, General Physics and Astronomy, 02 engineering and technology, 021001 nanoscience & nanotechnology, 01 natural sciences, Ion, Laser linewidth, Ion implantation, Quantum dot, 0103 physical sciences, Optoelectronics, Rapid thermal annealing, [SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics, 0210 nano-technology, business, ComputingMilieux_MISCELLANEOUS
Abstract

This work reports on InAs/GaAs quantum dots (QDs) intermixing, induced by phosphorous ion implantation and subsequent rapid thermal annealing. The implantation process was carried out at room temperature at various doses ( 5 × 10 10 – 10 14 ions / cm 2 ), where the ions were accelerated at 50 keV. To promote the atomic intermixing, implanted samples are subjected to rapid thermal annealing at 675 °C for 30 s. Low temperature photoluminescence (PL) measurements are carried out to investigate the influence of the interdiffusion process on the optical and electronic properties of the QDs. PL emission energy; linewidth and integrated intensity are found to exhibit a drastic dependence on the ion implantation doses. The band gap tuning limit has been achieved for an implantation dose of 5 × 10 13 ions / cm 2 . However, our measurement reveals that the accumulated defects for implantation doses higher than 10 12 ions / cm 2 drive the system towards the degradation of the QDs structure's quality.

Published
2008

20. Enhancement of the 2DEG density in AlGaAs/InGaAs/GaAs P-HEMTs structures grown by MBE on (311)A and (111)A GaAs substrates

Author

L. Sfaxi, Catherine Bru-Chevallier, S. Rekaya, Hassen Maaref, L. Bouzaiene, Laboratoire de Micro-optoélectronique et Nanostructures [Monastir], Faculté des Sciences de Monastir (FSM), Université de Monastir - University of Monastir (UM)-Université de Monastir - University of Monastir (UM), INL - Spectroscopies et Nanomatériaux (INL - S&N), Institut des Nanotechnologies de Lyon (INL), École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-École Centrale de Lyon (ECL), Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), and BRU CHEVALLIER, Catherine

Subjects
Electron density, Photoluminescence, Materials science, [SPI] Engineering Sciences [physics], [SPI.NANO] Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics, Bioengineering, 02 engineering and technology, Substrate (electronics), High-electron-mobility transistor, Epitaxy, 01 natural sciences, 7. Clean energy, Biomaterials, Condensed Matter::Materials Science, [SPI]Engineering Sciences [physics], 0103 physical sciences, [SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics, ComputingMilieux_MISCELLANEOUS, 010302 applied physics, Condensed matter physics, Heterojunction, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, 021001 nanoscience & nanotechnology, Mechanics of Materials, 0210 nano-technology, Fermi gas, Molecular beam epitaxy
Abstract

The pseudomorphic high electron mobility transistor (P-HEMT) structure materials Al0.33Ga0.7As/In0.1Ga0.9As/GaAs have been grown by molecular beam epitaxy (MBE) on (311)A and (111)A GaAs substrates. The epitaxy of strain heterostructure on high index GaAs substrate has led to new growth phenomena, material properties and device applications. The photoluminescence (PL) spectra of the structures have been measured at low temperature. The dominant emission in the PL spectra is due to the recombination from the first electron (e1) subband to the first heavy-hole (hh1) subband (E11: e1–hh1). This feature (E11) is a relatively broad peak and has a typical asymmetric line shape. The transformation of the PL spectra in the close vicinity of the Fermi edge (EF) under different excitation densities gives strong evidence for the Fermi Edge Singularity (FES) existence. The density of the quasi-two-dimensional electron gas (2DEG) determined by PL study (nsPL), is in sufficient agreement with the values found from Hall measurements nsHall at 77 K. The results prove an increase of the electron density in sample grown on GaAs (111)A and (311)A rather than in equivalent sample grown on (001) GaAs substrate. This effect is in good agreement with our theoretical prediction, which is based on a self-consistent solution of the coupled Schrodinger and Poisson equations.

Published
2008

21. Optical characterisation of single InAs quantum dots on GaAs substrate emitting at 1.3 μm

Author

Nicolas Chauvin, Catherine Bru-Chevallier, Bouraoui Ilahi, Hassen Maaref, L. Sfaxi, M. Baira, Laboratoire de physique de la matière (LPM), Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Micro-optoélectronique et Nanostructures [Monastir], Faculté des Sciences de Monastir (FSM), Université de Monastir - University of Monastir (UM)-Université de Monastir - University of Monastir (UM), and Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)

Subjects
Photoluminescence, Exciton, 02 engineering and technology, Substrate (electronics), 01 natural sciences, [SPI.MAT]Engineering Sciences [physics]/Materials, Condensed Matter::Materials Science, [SPI]Engineering Sciences [physics], 0103 physical sciences, Emission spectrum, 010306 general physics, Spectroscopy, Biexciton, ComputingMilieux_MISCELLANEOUS, Condensed matter physics, Condensed Matter::Other, business.industry, Chemistry, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Quantum dot laser, Quantum dot, [SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic, Optoelectronics, 0210 nano-technology, business
Abstract

Single InAs/GaAs quantum dots are studied using micro-photoluminescence spectroscopy. Single dot spectroscopy shows an antibinding biexciton. Some of these quantum dots are laterally coupled due to an anisotropic dot repartition. At low excitation power density, four excitons emissions are observed and are interpreted as the four possible exciton recombinations of two coupled quantum dots. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Published
2006

22. Optimizing the spacer layer thickness of vertically stacked InAs/GaAs quantum dots

Author

Olivier Marty, Bassem Salem, Hassen Maaref, Bouraoui Ilahi, L. Sfaxi, Georges Bremond, F. Hassen, L. Bouzaiene, Laboratoire de Micro-optoélectronique et Nanostructures [Monastir], Faculté des Sciences de Monastir (FSM), Université de Monastir - University of Monastir (UM)-Université de Monastir - University of Monastir (UM), Laboratoire des technologies de la microélectronique (LTM), Université Joseph Fourier - Grenoble 1 (UJF)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de physique de la matière (LPM), Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Electronique, Nanotechnologies, Capteurs (LENAC), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Laboratoire de micro-optoelectronique et nanostructures, Université de Monastir - University of Monastir (UM), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Photoluminescence, Yield (engineering), Materials science, Field (physics), business.industry, Bioengineering, 02 engineering and technology, 021001 nanoscience & nanotechnology, 01 natural sciences, Biomaterials, Mechanics of Materials, Quantum dot, 0103 physical sciences, Optoelectronics, Coupling (piping), [SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics, 010306 general physics, 0210 nano-technology, business, Spectroscopy, Excitation, ComputingMilieux_MISCELLANEOUS, Molecular beam epitaxy
Abstract

Vertically stacked multilayers of self-organized InAs/GaAs quantum dots (QDs) structures with different GaAs intermediate layer thicknesses varying between 2.8 and 17 nm are grown by solid source molecular beam epitaxy (SSMBE) and investigated by photoluminescence spectroscopy (PL). For 17 nm thick GaAs spacer, the PL spectra show two well separated features attributed to the formation of two QDs family with a bimodal size distribution indicating no correlation between the dots in different layers. In the meanwhile, the structures having thinner spacer thickness demonstrate single PL peaks showing an enhancement of high energy side asymmetrical broadening when increasing the excitation power. The corresponding emission energies exhibit a red shift when the spacer layer thickness decreases and correlated with the enhancement of the vertical electronic coupling as well as the rise of the QD's size in the upper layers induced by the build up of the strain field along the columns. The spacer thickness of 8.5 nm is found to yield the best optical properties.

Published
2006

23. Toward long wavelength low density InAs/GaAs quantum dots

Author

Georges Bremond, Hassen Maaref, L. Sfaxi, M. Baira, E. Tranvouez, Bouraoui Ilahi, C. Bru-Chevalier, Faculté des Sciences de Monastir (FSM), Université de Monastir - University of Monastir (UM), Laboratoire de Micro-optoélectronique et Nanostructures [Monastir], Université de Monastir - University of Monastir (UM)-Université de Monastir - University of Monastir (UM), Laboratoire de Photophysique Moléculaire (PPM), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), INL - Spectroscopies et Nanomatériaux (INL - S&N), Institut des Nanotechnologies de Lyon (INL), Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-École Centrale de Lyon (ECL), Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-École supérieure de Chimie Physique Electronique de Lyon (CPE), École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-École Centrale de Lyon (ECL), and Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Photoluminescence, General Physics and Astronomy, 02 engineering and technology, 021001 nanoscience & nanotechnology, 01 natural sciences, Blueshift, Full width at half maximum, [SPI]Engineering Sciences [physics], Quantum dot, Excited state, 0103 physical sciences, [SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic, Atomic physics, 010306 general physics, 0210 nano-technology, Spectroscopy, Deposition (law), ComputingMilieux_MISCELLANEOUS, Molecular beam epitaxy
Abstract

Optical and morphological properties of solid source molecular beam epitaxy (MBE) grown InAs/GaAs quantum dots are investigated by photoluminescence spectroscopy (PL) and atomic force microscopy (AFM) as a function of the growth rate. The 10 K relatively high excitation density PL spectra of the investigated samples reveal the existence of multipeaks characterizing fundamental states and corresponding excited states. The emission energies are red-shifted by approximately 70 meV, when the InAs deposition rate is reduced from 0.069 ML/s to 0.013 ML/s. By further reducing the growth rate down to 0.003 ML/s an unexpected blue shift of the emission energy occurs. AFM observations, carried out on similar uncapped samples, show a monotonic decrease of the QDs density with decreasing QDs material's deposition rate. For a growth rate of 0.003 ML/s, islands density of 4.9 × 10 9 cm −2 has been achieved with a room temperature PL full width at half maximum (FWHM) of 22 meV. For the later growth rate, the blue shift of the emission energy has been correlated with desorption of In atoms during InAs deposition.

Published
2006

24. Radiative N-localized recombination and confinement in GaAsN/GaAs epilayers and quantum well structures

Author

F. Hassen, Faouzi Saidi, Hassen Maaref, Yves Monteil, H. Dumont, Laurent Auvray, Laboratoire des Multimatériaux et Interfaces (LMI), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Micro-optoélectronique et Nanostructures [Monastir], Faculté des Sciences de Monastir (FSM), Université de Monastir - University of Monastir (UM)-Université de Monastir - University of Monastir (UM), and Auvray, Laurent

Subjects
Photoluminescence, Materials science, Exciton, 02 engineering and technology, 01 natural sciences, [PHYS] Physics [physics], Inorganic Chemistry, Condensed Matter::Materials Science, 0103 physical sciences, Radiative transfer, Spontaneous emission, Electrical and Electronic Engineering, Physical and Theoretical Chemistry, Spectroscopy, Quantum well, ComputingMilieux_MISCELLANEOUS, 010302 applied physics, [PHYS]Physics [physics], Condensed matter physics, Condensed Matter::Other, Organic Chemistry, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, 021001 nanoscience & nanotechnology, Atomic and Molecular Physics, and Optics, Electronic, Optical and Magnetic Materials, Blueshift, 0210 nano-technology, Excitation, Recombination
Abstract

The photoluminescence (PL) properties of GaAsN/GaAs epilayers and single quantum wells (QWs) have been investigated as a function of the excitation density and the sample temperature (10–300 K). At low temperatures, the PL spectra were sensitive to the excitation density for epilayers and QWs. For both structures, a blue shift of the PL peak is noted with increasing the excitation power. In contrast, the temperature dependence shows different behaviors for the bulk epilayers and for the quantum wells structures. An S-shape of the PL peak energy versus temperature has been observed for the GaAsN/GaAs epilayer while the QWs peak energy decreases monotically with the sample temperature and could be fitted by conventional Varshni’s law. This behavior is due to the exciton localization effect which is induced by the local fluctuation of nitrogen concentration.

Published
2003

25. Excitons localization effects in GaAsN/GaAs epilayers grown by MOCVD

Author

Hassen Maaref, Faouzi Saidi, F. Hassen, Laurent Auvray, Yves Monteil, H. Dumont, Laboratoire de Micro-optoélectronique et Nanostructures [Monastir], Faculté des Sciences de Monastir (FSM), Université de Monastir - University of Monastir (UM)-Université de Monastir - University of Monastir (UM), Laboratoire des Multimatériaux et Interfaces (LMI), Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
010302 applied physics, [PHYS]Physics [physics], Range (particle radiation), Photoluminescence, Materials science, Exciton, Analytical chemistry, chemistry.chemical_element, Bioengineering, 02 engineering and technology, Chemical vapor deposition, Nanosecond, 021001 nanoscience & nanotechnology, 01 natural sciences, Nitrogen, Biomaterials, chemistry, Mechanics of Materials, 0103 physical sciences, Metalorganic vapour phase epitaxy, 0210 nano-technology, Recombination, ComputingMilieux_MISCELLANEOUS
Abstract

Optical studies of GaAs 1− x N x /GaAs epilayers grown by metal-organic chemical vapour deposition (MOCVD), with low nitrogen concentration (1.65% and 2.2%), have been achieved by a number of optical techniques such as photoluminescence (PL), photoreflectance (PR) spectroscopies and time-resolved PL (TR-PL) measurements in the nanosecond range. It has been shown that the increase of the nitrogen fraction causes a red shift of the PL emission band compared to the GaAs one. TR-PL results at 12 K reveal that the decay time is clearly dependent on the emission energy. It increases for lower emission energy. From the temperature PL decay lifetime study, we suggest that PL emission is dominated by the recombination of localized excitons trapped by potential fluctuations of the near band edge induced by compositional fluctuations in GaAsN epilayer.

Published
2002

26. Auger effect as the origin of the fast-luminescent band of freshly anodized porous silicon

Author

H. Maâref, I. Mihalcescu, J. C. Vial, R. M'ghaïeth, Laboratoire de Micro-optoélectronique et Nanostructures [Monastir], Faculté des Sciences de Monastir (FSM), Université de Monastir - University of Monastir (UM)-Université de Monastir - University of Monastir (UM), Laboratoire de Spectrométrie Physique (LSP), and Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Auger effect, Anodizing, 02 engineering and technology, 021001 nanoscience & nanotechnology, Porous silicon, 01 natural sciences, symbols.namesake, Chemical engineering, 0103 physical sciences, symbols, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], 010306 general physics, 0210 nano-technology, Luminescence, Porous medium, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
1999

27. Porous silicon: photoluminescence decay in the nanosecond range

Author

H. Maâref, J. C. Vial, I. Mihalcescu, R. M'ghaïeth, Laboratoire de Micro-optoélectronique et Nanostructures [Monastir], Faculté des Sciences de Monastir (FSM), Université de Monastir - University of Monastir (UM)-Université de Monastir - University of Monastir (UM), Laboratoire de Spectrométrie Physique (LSP), and Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)

Subjects
010302 applied physics, Range (particle radiation), Photoluminescence, Nanostructure, Materials science, Silicon, General Engineering, Analytical chemistry, chemistry.chemical_element, 02 engineering and technology, Nanosecond, 021001 nanoscience & nanotechnology, Porous silicon, 01 natural sciences, chemistry, 0103 physical sciences, Wafer, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], 0210 nano-technology, Excitation, ComputingMilieux_MISCELLANEOUS
Abstract

Unlike the slow band (S-band), there is currently no clear spectroscopic signature which links the fast band (F-band) to the Si nanostructure. Time resolved photoluminescence (TRPL) was employed in the present work to study the porous silicon photoluminescence decay behavior in the nanosecond range, namely the F-band. Measurements were performed at room temperature on oxidized and fresh porous silicon samples. It was shown that the fast (ns) component had an extrinsic origin for oxidized samples, while the fresh samples exhibited an intrinsic behavior for both the fast and slow (10 μs) components. The excitation intensity dependence of the PL intensity was studied and showed different behavior of the F-band in both oxidized and fresh samples.

Published
1999

28. Effect of carriers transfer behavior on the optical properties of InAs quantum dots embedded in AlGaAs/GaAs heterojunction

Author

H. Khmissi, Hassen Maaref, L. Sfaxi, Catherine Bru-Chevallier, L. Bouzaiene, Faouzi Saidi, Laboratoire de Micro-optoélectronique et Nanostructures [Monastir], Faculté des Sciences de Monastir (FSM), Université de Monastir - University of Monastir (UM)-Université de Monastir - University of Monastir (UM), Institut des Nanotechnologies de Lyon (INL), École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), INL - Spectroscopies et Nanomatériaux (INL - S&N), and Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-École Centrale de Lyon (ECL)

Subjects
010302 applied physics, Photoluminescence, Materials science, business.industry, General Physics and Astronomy, Heterojunction, 02 engineering and technology, High-electron-mobility transistor, 021001 nanoscience & nanotechnology, 01 natural sciences, Blueshift, [SPI]Engineering Sciences [physics], Full width at half maximum, Quantum dot, Excited state, 0103 physical sciences, Optoelectronics, [SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics, 0210 nano-technology, business, Ground state, ComputingMilieux_MISCELLANEOUS
Abstract

In this paper, we have investigated the optical properties of InAs quantum dots (Qds) embedded near the channel of a delta-doped AlGaAs/GaAs high electron mobility transistor. In order to study the influence of the two-dimensional electron gas (2DEG) on the luminescence of QDs, we have prepared different structures in which we varied the thickness (d) separating the interface of AlGaAs/GaAs heterojunction from the InAs quantum dot layer. Various photoluminescence (PL) behaviors are observed when d decreases. PL spectra show the existence of two peaks which can be attributed to transition energies from the ground state (E1-HH1) and the first excited state (E2-HH2). A blueshift, a decrease in the PL intensity and an increase in the full width at half maximum of the PL peaks are observed, when the InAs QDs layer is closer to the 2DEG.

Published
2010

29. Inhomogeneous broadening and alloy intermixing in low proton dose implanted InAs/GaAs self-assembled quantum dots

Author

Hassen Maaref, Denis Morris, L. Sfaxi, Bassem Salem, Z. Zaâboub, Vincent Aimez, Bouraoui Ilahi, Laboratoire de Micro-optoélectronique et Nanostructures [Monastir], Faculté des Sciences de Monastir (FSM), Université de Monastir - University of Monastir (UM)-Université de Monastir - University of Monastir (UM), Laboratoire de micro-optoelectronique et nanostructures, Université de Monastir - University of Monastir (UM), Laboratoire des technologies de la microélectronique (LTM), Université Joseph Fourier - Grenoble 1 (UJF)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Université de Sherbrooke (UdeS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Photoluminescence, Materials science, Proton, Annealing (metallurgy), Bioengineering, 02 engineering and technology, 01 natural sciences, Molecular physics, Ion, Laser linewidth, 0103 physical sciences, General Materials Science, Photoluminescence excitation, [SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics, Electrical and Electronic Engineering, ComputingMilieux_MISCELLANEOUS, 010302 applied physics, business.industry, Mechanical Engineering, General Chemistry, 021001 nanoscience & nanotechnology, Ion implantation, Mechanics of Materials, Quantum dot, Optoelectronics, 0210 nano-technology, business
Abstract

In this work, low-temperature photoluminescence (PL) and photoluminescence excitation (PLE) experiments have been carried out to investigate the optical and electronic properties of InAs/GaAs quantum dots (QDs) subjected to room-temperature proton implantation at various doses (5 × 10 10 –10 14 ions cm −2 ) and subsequent thermal annealing. The energy shift of the main QD emission band is found to increase with increasing implantation dose. Our measurements show clear evidence of an inhomogeneous In/Ga intermixing at low proton implantation doses (5 × 10 11 ions cm −2 ), giving rise to the coexistence of intermixed and non-intermixed QDs. For higher implantation doses, a decrease of both the PL linewidth and the intersublevel spacing energy have been found to occur, suggesting that the dot-size, dot-composition and dot-strain distributions evolve towards more uniform ones. (Some figures in this article are in colour only in the electronic version)

Published
2008

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