Moncef SAID - Academia.edu (original) (raw)
Papers by Moncef SAID
The Journal of Chemical Physics
Using first-principles calculations, we have studied the structural and electronic properties of ... more Using first-principles calculations, we have studied the structural and electronic properties of ZrOX (X = S, Se, and Te) monolayers and their van der Waals heterostructures in the tetragonal structure. Our results show that these monolayers are dynamically stable and are semiconductors with electronic bandgaps ranging from 1.98 to 3.16 eV as obtained with the GW approximation. By computing their band edges, we show that ZrOS and ZrOSe are of interest for water splitting applications. In addition, the van der Waals heterostructures formed by these monolayers show a type I band alignment for ZrOTe/ZrOSe and a type II alignment for the other two heterostructures, making them potential candidates for certain optoelectronic applications involving electron/hole separation.
Solid State Communications
Abstract Two-dimensional materials, known as 2D materials, have attracted increasing interest in ... more Abstract Two-dimensional materials, known as 2D materials, have attracted increasing interest in recent years. 2D semiconductors can potentially be used in a multitude of applications in flexible electronics and atomic applications. In this framework, we investigate the structural, vibrational, and electronic properties of new 2D SrFCl and SrFBr monolayers, employing density functional theory and beyond with GW approximation. We have obtained these monolayers are dynamically stable since there are not imaginary modes in their phonon dispersion, confirming the stability of the two-dimensional form of these compounds. Our GW results show that the bandgap energy of SrFCl monolayer is significantly larger than the bandgap of PbFCl monolayer (6.38 eV with GW) by ∼ 1.17 eV. Further, the bandgap energy value obtained for the SrFBr monolayer is larger than the bandgap of the PbFI sheet (6.64 eV with GW) by ∼ 0.62 eV.
licenses/by/4.0). Please note that the reuse, redistribution and reproduction in particular requi... more licenses/by/4.0). Please note that the reuse, redistribution and reproduction in particular requires that the authors and source are credited. The license is subject to the Beilstein Journal of Nanotechnology terms and conditions: (https://www.beilstein-journals.org/bjnano) Supporting Information for Electronic properties of several two dimensional halides from ab initio calculations Mohamed Barhoumi, Ali Abboud, Lamjed Debbichi, Moncef Said, Torbjörn Björkman, Dario Rocca and Sébastien Lebègue
Optik, 2021
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Optik, 2021
Abstract In this report, we have theoretically described, analyzed, and investigated the nonlinea... more Abstract In this report, we have theoretically described, analyzed, and investigated the nonlinear optical properties in the core/shell nanostructure of GaN core surrounded by InxGa1−xN shell. Taking in consideration the effective-mass formalism, electron eigenenergies and corresponding wave functions were calculated. Employing the compact density matrix method, highlight quantities namely the third-order nonlinear susceptibility associated with intersubband transition is numerically computed and discussed as a function of CSQD radii and indium (In) composition. Our simulations have revealed the tunability of the position and the magnitude of the resonance peaks by adjusting the geometrical parameters and the indium ratio. The magnitude of both real and imaginary parts of the susceptibility is remarkably aroused and the peaks are red shifted with the rise of core/shell radii.
Optik, 2020
Please cite this article as: M. Barhoumi, M. Said, Correction of band-gap energy and dielectric f... more Please cite this article as: M. Barhoumi, M. Said, Correction of band-gap energy and dielectric function of BiOX bulk withGW and BSE, <![CDATA[Optik]]> (2020), doi: https://doi.org/ This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Materials Science and Engineering: B, 2021
So far, semiconductors materials have gained huge attention from researchers because of their sup... more So far, semiconductors materials have gained huge attention from researchers because of their superior electrocatalytic activity and employment in different areas. The bismuth oxyhalides BiOXs bulks have great electrocatalytic properties and stability. Astonishingly, few of them have synthesized and there is still a lack of theoretical and experimental data on their bandgap energy, which limits the chance of producing new physical properties. Using density functional theory and beyond with GW and GW BSE approaches, we investigate the electronic and optical properties such as absorption coefficient of bismuth oxyhalides BiOXs (where, X = F, Cl, Br, and I). Our results show that the GW bandgap nature of BiOF is direct, whereas the GW bandgaps of BiOCl, BiOBr, and BiOI are indirect, which is a range from 2.33 eV (BiOI) to 4.04 eV (BiOF). Here, we suggest that can be taken the GW bandgap calculations of BiOCl as a reference to the place of experimental values. Under an external electric field, we succeed to reduce easily and quickly the bandgaps energy of our compounds. Besides, we show that under an external electric field a semiconductor can be changed to a metal with a strong field of more than 0.5 V/Å. In this framework, we have shown that this strategy is better than the incorporation method for engineering in order to find material with a bandgap that we want. We found that the dramatic redshift of the peaks at the BSE level as compared to DFT and RPA indicates strong excitonic effects.
Chemical Physics, 2020
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Physica E: Low-dimensional Systems and Nanostructures, 2020
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Results in Physics, 2019
The third order nonlinear optical susceptibility is investigated within the frame work of the eff... more The third order nonlinear optical susceptibility is investigated within the frame work of the effective-mass approximation, for the ZnS/CdS/ZnS quantum dot-quantum well. The numerical results revealed that the position and the intensity of the susceptibility peaks can be modulated by varying core or shell radius. With increasing the width of shell, the peaks are redshifted and the intensities are intensified, the ZnS core size has also a crucial impact on nonlinear susceptibility. The obtained results can serve the photonic and optoelectronic fields.
Journal of Fluorine Chemistry, 2018
Since the search for new two-dimensional III-V films with high structural stability and a large g... more Since the search for new two-dimensional III-V films with high structural stability and a large gap is urgently required. We propose a universal strategy to obtain a stable material with a large band-gap. Using density functional theory, we study the vibrational and electronic properties of InBi honeycomb film functionalized through fluorine atoms. Also, since selecting a suitable substrate for InBi 2D film functionalized is a very important issue for devices applications, we investigate the dynamic stability and electronic band structures of InBi with fluorination deposited on graphene. Our results show that the predicted geometry can well reproduce the structural parameters, where very well agreement was obtained between the calculated and previous studies for InBi monolayer. Surprisingly, for the two cases of functionalization, which are considered, i.e, a sheet of InBi half functionalized and other fully covered by F atoms; the results indicate that the fluorine atom can stabilize InBi monolayer, where the fluorine removes the imaginary frequency modes from the phonon curve of InBi. Besides, our GGA+vdW calculations show that the band-gap in these two extremes cases is significantly larger than the InBi film with hydrogenation (0.19 eV with GGA+SOC) by ∼ 0.78 eV and with a methyl group (0.29 eV with GGA+SOC) by ∼ 0.68 eV. Further, the band-gap obtained for InBi without and with half fluorination deposited on graphene is larger than the InBi film with a methyl group on the h-BN substrate.
The Journal of Chemical Physics, 2017
By means of ab initio calculations, we study the functionalization of graphene by different chemi... more By means of ab initio calculations, we study the functionalization of graphene by different chemical groups such as hydroxyl, nitrile, or methyl. Two extreme cases of functionalization are considered: a single group on a supercell of graphene and a sheet of graphene fully functionalized. Once the equilibrium geometry is obtained by density functional theory, we found that the systems are metallic when a single group is attached to the sheet of graphene. With the exception of the nitrile functionalized boat configuration, a large bandgap is obtained at full coverage. Specifically, by using the GW approximation, our calculated bandgaps are direct and range between 5.0 and 5.5 eV for different configurations of hydroxyl functionalized graphene. An indirect GW bandgap of 6.50 eV was found in nitrile functionalized graphene while the methyl group functionalization leads to a direct bandgap with a value of 4.50 eV. Since in the two limiting cases of minimal and full coverage, the electron...
Optik, 2018
In this paper, energy levels of electrons and holes for different shapes of isolated and self-org... more In this paper, energy levels of electrons and holes for different shapes of isolated and self-organized InAs/InP quantum wire are calculated. We have used a theoretical method based on the coordinate transformation employing a newly analytical function to resolve the Schrödinger equation. The purpose of this work is to show how the shape of the quantum wire depend on the parameters introduced in the function and to discuss the effect of the wire height on the energy levels. The optical transitions energies are also investigated.
Physica E: Low-dimensional Systems and Nanostructures, 2018
Please cite this article as: M. Barhoumi, K. Lazaar, M. Said, Electronic and vibrational properti... more Please cite this article as: M. Barhoumi, K. Lazaar, M. Said, Electronic and vibrational properties of TMDs heterogeneous bilayers, nontwisted bilayers silicene/TMDs heterostructures and photovoltaic heterojunctions of fullerenes with TMDs monolayers,
The Journal of Chemical Physics, 2017
Using first principle calculations, we have studied the structural and electronic properties of t... more Using first principle calculations, we have studied the structural and electronic properties of two dimensional bilayers of indium and gallium chalcogenides. With density functional theory corrected for van der Waals interactions, the different modes of stacking were investigated in a systematic way, and several of them were found to compete in energy. Then, their band structures were obtained with the GW approximation and found to correspond to indirect bandgap semiconductors with a small dependency on the mode of stacking. Finally, by analysing the electron density, it appeared that GaSe–InS is a promising system for electron-hole separation.
Journal of Magnetism and Magnetic Materials, 2017
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service... more This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. First-principles investigation of the effect of oxidation on the electronic structure and magnetic properties at the FeRh/MgO (001) interface
Journal of Physics C: Solid State Physics, 1987
ABSTRACT
Journal of Modeling, Simulation, Identification, and Control, 2013
Surface Science, 2009
We have investigated the growth of Ni on Pt stepped surfaces with (1 1 1) terraces by means of po... more We have investigated the growth of Ni on Pt stepped surfaces with (1 1 1) terraces by means of potentials derived from the second moment approximation in a tight-binding model. The activation energies associated to these processes are determined. The Schwoebel barriers of Ni atoms descending steps of Pt stepped surfaces are calculated for different kinds of straight steps (A and B steps) differing by the orientation of the ledge. In addition, we study the diffusion of Ni adatoms at fcc or hcp sites in the presence of small adislands on the terraces, in the vicinity of the A and B steps. We show that a good estimate of the potential wells and diffusion barriers could be given by introducing a lateral effective pair interaction model, the interactions extending up to the next nearest neighbors. Finally, we have carried out Kinetic Monte-Carlo simulations to investigate the Ni wire formation at Pt step edges and the influence of the exchange processes in the alloy formation.
Solid State Communications, 1986
ABSTRACT
The Journal of Chemical Physics
Using first-principles calculations, we have studied the structural and electronic properties of ... more Using first-principles calculations, we have studied the structural and electronic properties of ZrOX (X = S, Se, and Te) monolayers and their van der Waals heterostructures in the tetragonal structure. Our results show that these monolayers are dynamically stable and are semiconductors with electronic bandgaps ranging from 1.98 to 3.16 eV as obtained with the GW approximation. By computing their band edges, we show that ZrOS and ZrOSe are of interest for water splitting applications. In addition, the van der Waals heterostructures formed by these monolayers show a type I band alignment for ZrOTe/ZrOSe and a type II alignment for the other two heterostructures, making them potential candidates for certain optoelectronic applications involving electron/hole separation.
Solid State Communications
Abstract Two-dimensional materials, known as 2D materials, have attracted increasing interest in ... more Abstract Two-dimensional materials, known as 2D materials, have attracted increasing interest in recent years. 2D semiconductors can potentially be used in a multitude of applications in flexible electronics and atomic applications. In this framework, we investigate the structural, vibrational, and electronic properties of new 2D SrFCl and SrFBr monolayers, employing density functional theory and beyond with GW approximation. We have obtained these monolayers are dynamically stable since there are not imaginary modes in their phonon dispersion, confirming the stability of the two-dimensional form of these compounds. Our GW results show that the bandgap energy of SrFCl monolayer is significantly larger than the bandgap of PbFCl monolayer (6.38 eV with GW) by ∼ 1.17 eV. Further, the bandgap energy value obtained for the SrFBr monolayer is larger than the bandgap of the PbFI sheet (6.64 eV with GW) by ∼ 0.62 eV.
licenses/by/4.0). Please note that the reuse, redistribution and reproduction in particular requi... more licenses/by/4.0). Please note that the reuse, redistribution and reproduction in particular requires that the authors and source are credited. The license is subject to the Beilstein Journal of Nanotechnology terms and conditions: (https://www.beilstein-journals.org/bjnano) Supporting Information for Electronic properties of several two dimensional halides from ab initio calculations Mohamed Barhoumi, Ali Abboud, Lamjed Debbichi, Moncef Said, Torbjörn Björkman, Dario Rocca and Sébastien Lebègue
Optik, 2021
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Optik, 2021
Abstract In this report, we have theoretically described, analyzed, and investigated the nonlinea... more Abstract In this report, we have theoretically described, analyzed, and investigated the nonlinear optical properties in the core/shell nanostructure of GaN core surrounded by InxGa1−xN shell. Taking in consideration the effective-mass formalism, electron eigenenergies and corresponding wave functions were calculated. Employing the compact density matrix method, highlight quantities namely the third-order nonlinear susceptibility associated with intersubband transition is numerically computed and discussed as a function of CSQD radii and indium (In) composition. Our simulations have revealed the tunability of the position and the magnitude of the resonance peaks by adjusting the geometrical parameters and the indium ratio. The magnitude of both real and imaginary parts of the susceptibility is remarkably aroused and the peaks are red shifted with the rise of core/shell radii.
Optik, 2020
Please cite this article as: M. Barhoumi, M. Said, Correction of band-gap energy and dielectric f... more Please cite this article as: M. Barhoumi, M. Said, Correction of band-gap energy and dielectric function of BiOX bulk withGW and BSE, <![CDATA[Optik]]> (2020), doi: https://doi.org/ This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Materials Science and Engineering: B, 2021
So far, semiconductors materials have gained huge attention from researchers because of their sup... more So far, semiconductors materials have gained huge attention from researchers because of their superior electrocatalytic activity and employment in different areas. The bismuth oxyhalides BiOXs bulks have great electrocatalytic properties and stability. Astonishingly, few of them have synthesized and there is still a lack of theoretical and experimental data on their bandgap energy, which limits the chance of producing new physical properties. Using density functional theory and beyond with GW and GW BSE approaches, we investigate the electronic and optical properties such as absorption coefficient of bismuth oxyhalides BiOXs (where, X = F, Cl, Br, and I). Our results show that the GW bandgap nature of BiOF is direct, whereas the GW bandgaps of BiOCl, BiOBr, and BiOI are indirect, which is a range from 2.33 eV (BiOI) to 4.04 eV (BiOF). Here, we suggest that can be taken the GW bandgap calculations of BiOCl as a reference to the place of experimental values. Under an external electric field, we succeed to reduce easily and quickly the bandgaps energy of our compounds. Besides, we show that under an external electric field a semiconductor can be changed to a metal with a strong field of more than 0.5 V/Å. In this framework, we have shown that this strategy is better than the incorporation method for engineering in order to find material with a bandgap that we want. We found that the dramatic redshift of the peaks at the BSE level as compared to DFT and RPA indicates strong excitonic effects.
Chemical Physics, 2020
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Physica E: Low-dimensional Systems and Nanostructures, 2020
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Results in Physics, 2019
The third order nonlinear optical susceptibility is investigated within the frame work of the eff... more The third order nonlinear optical susceptibility is investigated within the frame work of the effective-mass approximation, for the ZnS/CdS/ZnS quantum dot-quantum well. The numerical results revealed that the position and the intensity of the susceptibility peaks can be modulated by varying core or shell radius. With increasing the width of shell, the peaks are redshifted and the intensities are intensified, the ZnS core size has also a crucial impact on nonlinear susceptibility. The obtained results can serve the photonic and optoelectronic fields.
Journal of Fluorine Chemistry, 2018
Since the search for new two-dimensional III-V films with high structural stability and a large g... more Since the search for new two-dimensional III-V films with high structural stability and a large gap is urgently required. We propose a universal strategy to obtain a stable material with a large band-gap. Using density functional theory, we study the vibrational and electronic properties of InBi honeycomb film functionalized through fluorine atoms. Also, since selecting a suitable substrate for InBi 2D film functionalized is a very important issue for devices applications, we investigate the dynamic stability and electronic band structures of InBi with fluorination deposited on graphene. Our results show that the predicted geometry can well reproduce the structural parameters, where very well agreement was obtained between the calculated and previous studies for InBi monolayer. Surprisingly, for the two cases of functionalization, which are considered, i.e, a sheet of InBi half functionalized and other fully covered by F atoms; the results indicate that the fluorine atom can stabilize InBi monolayer, where the fluorine removes the imaginary frequency modes from the phonon curve of InBi. Besides, our GGA+vdW calculations show that the band-gap in these two extremes cases is significantly larger than the InBi film with hydrogenation (0.19 eV with GGA+SOC) by ∼ 0.78 eV and with a methyl group (0.29 eV with GGA+SOC) by ∼ 0.68 eV. Further, the band-gap obtained for InBi without and with half fluorination deposited on graphene is larger than the InBi film with a methyl group on the h-BN substrate.
The Journal of Chemical Physics, 2017
By means of ab initio calculations, we study the functionalization of graphene by different chemi... more By means of ab initio calculations, we study the functionalization of graphene by different chemical groups such as hydroxyl, nitrile, or methyl. Two extreme cases of functionalization are considered: a single group on a supercell of graphene and a sheet of graphene fully functionalized. Once the equilibrium geometry is obtained by density functional theory, we found that the systems are metallic when a single group is attached to the sheet of graphene. With the exception of the nitrile functionalized boat configuration, a large bandgap is obtained at full coverage. Specifically, by using the GW approximation, our calculated bandgaps are direct and range between 5.0 and 5.5 eV for different configurations of hydroxyl functionalized graphene. An indirect GW bandgap of 6.50 eV was found in nitrile functionalized graphene while the methyl group functionalization leads to a direct bandgap with a value of 4.50 eV. Since in the two limiting cases of minimal and full coverage, the electron...
Optik, 2018
In this paper, energy levels of electrons and holes for different shapes of isolated and self-org... more In this paper, energy levels of electrons and holes for different shapes of isolated and self-organized InAs/InP quantum wire are calculated. We have used a theoretical method based on the coordinate transformation employing a newly analytical function to resolve the Schrödinger equation. The purpose of this work is to show how the shape of the quantum wire depend on the parameters introduced in the function and to discuss the effect of the wire height on the energy levels. The optical transitions energies are also investigated.
Physica E: Low-dimensional Systems and Nanostructures, 2018
Please cite this article as: M. Barhoumi, K. Lazaar, M. Said, Electronic and vibrational properti... more Please cite this article as: M. Barhoumi, K. Lazaar, M. Said, Electronic and vibrational properties of TMDs heterogeneous bilayers, nontwisted bilayers silicene/TMDs heterostructures and photovoltaic heterojunctions of fullerenes with TMDs monolayers,
The Journal of Chemical Physics, 2017
Using first principle calculations, we have studied the structural and electronic properties of t... more Using first principle calculations, we have studied the structural and electronic properties of two dimensional bilayers of indium and gallium chalcogenides. With density functional theory corrected for van der Waals interactions, the different modes of stacking were investigated in a systematic way, and several of them were found to compete in energy. Then, their band structures were obtained with the GW approximation and found to correspond to indirect bandgap semiconductors with a small dependency on the mode of stacking. Finally, by analysing the electron density, it appeared that GaSe–InS is a promising system for electron-hole separation.
Journal of Magnetism and Magnetic Materials, 2017
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service... more This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. First-principles investigation of the effect of oxidation on the electronic structure and magnetic properties at the FeRh/MgO (001) interface
Journal of Physics C: Solid State Physics, 1987
ABSTRACT
Journal of Modeling, Simulation, Identification, and Control, 2013
Surface Science, 2009
We have investigated the growth of Ni on Pt stepped surfaces with (1 1 1) terraces by means of po... more We have investigated the growth of Ni on Pt stepped surfaces with (1 1 1) terraces by means of potentials derived from the second moment approximation in a tight-binding model. The activation energies associated to these processes are determined. The Schwoebel barriers of Ni atoms descending steps of Pt stepped surfaces are calculated for different kinds of straight steps (A and B steps) differing by the orientation of the ledge. In addition, we study the diffusion of Ni adatoms at fcc or hcp sites in the presence of small adislands on the terraces, in the vicinity of the A and B steps. We show that a good estimate of the potential wells and diffusion barriers could be given by introducing a lateral effective pair interaction model, the interactions extending up to the next nearest neighbors. Finally, we have carried out Kinetic Monte-Carlo simulations to investigate the Ni wire formation at Pt step edges and the influence of the exchange processes in the alloy formation.
Solid State Communications, 1986
ABSTRACT