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Auteur Boubekeur Boudine |
Documents disponibles écrits par cet auteur (4)
Affiner la recherche Interroger des sources externesElaboration et caractérisation des couches minces du semiconducteur ZnO pures et dopées par le Cadmium / Badis Rahal
Titre : Elaboration et caractérisation des couches minces du semiconducteur ZnO pures et dopées par le Cadmium Type de document : texte imprimé Auteurs : Badis Rahal, Auteur ; Boubekeur Boudine, Directeur de thèse Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2017 Importance : 117 f. Format : 30 cm. Note générale : 2 copies imprimées disponibles
Langues : Français (fre) Catégories : Français - Anglais
PhysiqueTags : Zinc oxide Cadmium oxide Nanocomposite Thin films Dip-coating Colloidal Sol-Gel Oxyde de zinc Oxyde de cadmium Couches minces Dip-Coating Colloïdale Index. décimale : 530 Physique Résumé : The present work consists in the elaboration and characterization of the undoped and
cadmium-doped ZnO with different concentrations of cadmium (Cd) (1, 2, 5 and 10% in weight)
thin films in order to improve the structural and optical properties of ZnO. The samples were
prepared using two methods; Colloidal and Sol-Gel and deposited on glass and silicon substrates
by the Dip-coating technique.
The structural characterization showed the formation of ZnO with hexagonal structure
(wurtzite) with a preferential orientation according to plane (002) (sol-gel method). With the
exception of doping with 10% Cd (colloidal method), the formation of the ZnO/CdO
nanocomposite was assisted. SEM and AFM images revealed the nanometric character of our
films. The Raman diffusion confirmed the results of the DRX that is the formation of ZnO with
hexagonal structure (wurtzite).
The RBS spectroscopy has proved the existence, in our films, of the elements (zinc,
cadmium and oxygen) and gave us an idea on the thickness of the thin films. The measurement
of ellipsometry allowed us to evaluate the refractive index of our films and to estimate their
thickness. UV-visible spectroscopy has shown that our layers have a transparency, in the visible,
which varies between 70 and 90%. And that the gap decreases with the increase in doping. The
photoluminescence of the films showed ultraviolet (UV) and visible emissions related to defects.
Auger analysis on layers deposited on silicon substrates gave us an estimate of the thickness.Diplôme : Doctorat en sciences En ligne : ../theses/physique/RAH7052.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=10548 Elaboration et caractérisation des couches minces du semiconducteur ZnO pures et dopées par le Cadmium [texte imprimé] / Badis Rahal, Auteur ; Boubekeur Boudine, Directeur de thèse . - جامعة الإخوة منتوري قسنطينة, 2017 . - 117 f. ; 30 cm.
2 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
PhysiqueTags : Zinc oxide Cadmium oxide Nanocomposite Thin films Dip-coating Colloidal Sol-Gel Oxyde de zinc Oxyde de cadmium Couches minces Dip-Coating Colloïdale Index. décimale : 530 Physique Résumé : The present work consists in the elaboration and characterization of the undoped and
cadmium-doped ZnO with different concentrations of cadmium (Cd) (1, 2, 5 and 10% in weight)
thin films in order to improve the structural and optical properties of ZnO. The samples were
prepared using two methods; Colloidal and Sol-Gel and deposited on glass and silicon substrates
by the Dip-coating technique.
The structural characterization showed the formation of ZnO with hexagonal structure
(wurtzite) with a preferential orientation according to plane (002) (sol-gel method). With the
exception of doping with 10% Cd (colloidal method), the formation of the ZnO/CdO
nanocomposite was assisted. SEM and AFM images revealed the nanometric character of our
films. The Raman diffusion confirmed the results of the DRX that is the formation of ZnO with
hexagonal structure (wurtzite).
The RBS spectroscopy has proved the existence, in our films, of the elements (zinc,
cadmium and oxygen) and gave us an idea on the thickness of the thin films. The measurement
of ellipsometry allowed us to evaluate the refractive index of our films and to estimate their
thickness. UV-visible spectroscopy has shown that our layers have a transparency, in the visible,
which varies between 70 and 90%. And that the gap decreases with the increase in doping. The
photoluminescence of the films showed ultraviolet (UV) and visible emissions related to defects.
Auger analysis on layers deposited on silicon substrates gave us an estimate of the thickness.Diplôme : Doctorat en sciences En ligne : ../theses/physique/RAH7052.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=10548 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité RAH/7052 RAH/7052 Thèse Bibliothèque principale Thèses Disponible
Titre : Fabrication and characterization of oxides. Type de document : texte imprimé Auteurs : Imene Ameur, Auteur ; Boubekeur Boudine, Directeur de thèse Mention d'édition : 11/07/2021 Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2021 Importance : 147 f. Format : 30 cm. Note générale : Doctorat 3éme CYCLE LMD.
1 copies imprimées disponibles
Langues : Anglais (eng) Catégories : Français - Anglais
PhysiqueTags : Physic: Nanomaterials and advanced materials ZnO MgO couches minces nanoparticules activités photocatalytique Thin films Photocatalytic activity أكسيد الزنك أكسيد المغنيزيوم الأغشية الرقيقة الجسيمات النانوية نشاط التحفيز الضوئي Index. décimale : 530 Physique Résumé :
The aim of this work is the synthesis and characterization of ZnO, MgO, Mg: ZnO and Er: MgO for the photocatalytic activity under UV irradiation. The films were synthesized using the sol-gel method and were deposited via dip-coating technique and annealing at Ta = 500 °C; also for NPs preparation, we used the sol-gel method at room temperature; then were annealed at T = 950 °C. Structural, surface morphology and optical characterizations of the thin films and the NPs were studied as a function of the dopant concentration. All the prepared samples were evaluated the photocatalytic activity against methylene blue dye under UV irradiation at room temperature. Structural characterization via XRD showed the formation of hexagonal structure of ZnO for
ZnO films, and the formation of MgO cubic structure for MgO films and NPs, while the NPs exhibited also a formation of Er2O3 cubic structure. EDX revealed that Mg had been incorporated into the ZnO, and Er has been also incorporated into MgO. Surface morphology via AFM showed that the RMS values increase with the increase of Mg
dopant from 4.46 to 12.30 nm, and the ESEM images showed that the films had wrinkles morphology. While the surface morphology of MgO NPs via TEM revealed that the nanoparticles agglomerate in rounded shaped aggregates with nanometric grain size. Optical characterization revealed that Mg doping enlarged the optical band-gap from 3.28 to 3.40 eV and dropped the Urbach energy from 332 to 322 meV for ZnO films. While the bandgap energy of MgO thin films achieved a value of 4.08 eV lower than the bulk value of MgO 7.8 eV, and for MgO NPs the Er decrease the optical band-gap from 5.87 to 5.46 eV. Finally, photocatalytic activity proved that the addition of Mg and Er as dopants has promoted faster the MB dye degradation for ZnO and MgO, due to multiple factors such as the surface area.
Diplôme : Doctorat En ligne : ../theses/physique/AME7807.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=11639 Fabrication and characterization of oxides. [texte imprimé] / Imene Ameur, Auteur ; Boubekeur Boudine, Directeur de thèse . - 11/07/2021 . - جامعة الإخوة منتوري قسنطينة, 2021 . - 147 f. ; 30 cm.
Doctorat 3éme CYCLE LMD.
1 copies imprimées disponibles
Langues : Anglais (eng)
Catégories : Français - Anglais
PhysiqueTags : Physic: Nanomaterials and advanced materials ZnO MgO couches minces nanoparticules activités photocatalytique Thin films Photocatalytic activity أكسيد الزنك أكسيد المغنيزيوم الأغشية الرقيقة الجسيمات النانوية نشاط التحفيز الضوئي Index. décimale : 530 Physique Résumé :
The aim of this work is the synthesis and characterization of ZnO, MgO, Mg: ZnO and Er: MgO for the photocatalytic activity under UV irradiation. The films were synthesized using the sol-gel method and were deposited via dip-coating technique and annealing at Ta = 500 °C; also for NPs preparation, we used the sol-gel method at room temperature; then were annealed at T = 950 °C. Structural, surface morphology and optical characterizations of the thin films and the NPs were studied as a function of the dopant concentration. All the prepared samples were evaluated the photocatalytic activity against methylene blue dye under UV irradiation at room temperature. Structural characterization via XRD showed the formation of hexagonal structure of ZnO for
ZnO films, and the formation of MgO cubic structure for MgO films and NPs, while the NPs exhibited also a formation of Er2O3 cubic structure. EDX revealed that Mg had been incorporated into the ZnO, and Er has been also incorporated into MgO. Surface morphology via AFM showed that the RMS values increase with the increase of Mg
dopant from 4.46 to 12.30 nm, and the ESEM images showed that the films had wrinkles morphology. While the surface morphology of MgO NPs via TEM revealed that the nanoparticles agglomerate in rounded shaped aggregates with nanometric grain size. Optical characterization revealed that Mg doping enlarged the optical band-gap from 3.28 to 3.40 eV and dropped the Urbach energy from 332 to 322 meV for ZnO films. While the bandgap energy of MgO thin films achieved a value of 4.08 eV lower than the bulk value of MgO 7.8 eV, and for MgO NPs the Er decrease the optical band-gap from 5.87 to 5.46 eV. Finally, photocatalytic activity proved that the addition of Mg and Er as dopants has promoted faster the MB dye degradation for ZnO and MgO, due to multiple factors such as the surface area.
Diplôme : Doctorat En ligne : ../theses/physique/AME7807.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=11639 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité AME/7807 AME/7807 Thèse Bibliothèque principale Thèses Disponible
Titre : Study of a nanostructured compound based on II-VI semiconductors (ZnS). Type de document : texte imprimé Auteurs : Khaoula Ghezali, Auteur ; Boubekeur Boudine, Directeur de thèse ; Amor Azizi, Directeur de thèse Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2018 Importance : 131 f. Format : 30 cm. Note générale : 2 copies imprimées disponibles
Langues : Anglais (eng) Catégories : Français - Anglais
PhysiqueTags : Electrodéposition nanostructures ZnS Mott-Schottky TRPL. الهياكل النانوية كبريت الزنك العناصر الأرضية النادرة Index. décimale : 530 Physique Résumé : This thesis deals with the elaboration and characterization of zinc sulfide (ZnS) nanostructures for photovoltaic applications. We used the electrochemical deposition method to synthesize these films, and this, for its simplicity and low cost. The deposit solution is composed of zinc sulfate and sodium thiosulfate (Na2S2O3) as sources of Zn and S, respectively. This work is devised on two part. First, the samples were prepared by varying several parameters such as zinc concentration, pH, deposition potential and time deposition. The obtained nanostructures were subjected to various characterizations such as electronic (Mott-Schottky), morphological (SEM, AFM), Structural (XRD) and optical properties (UV-Vis). The Mott-Schottky measures showed that the films have an n-type conductivity when the carrier concentration and flat band potential was strongly depend on the different parameters. The morphological characterization of the samples by AFM and SEM showed a significant change of the with topography different parameters. The structural analysis shows that the obtained films are monocrystalline, they exhibit a zinc blend structure. The preferential orientation is strongly related to the experimental parameters. Studied at the end of this part the optical results show a lower transmittance. The second part is devoted to the doping of ZnS nanostructures by rare earths (Er, Sm). An improvement of optical properties (transmittance 80%) was obtained when we increase the dopants concentration and the optical band gap increases after doping from 3.54 to 3.8 eV for both dopants. The time-resolved photoluminescence decay were used to determine the charge carrier transfer (life time) of ZnS with the Er and Sm doping.
Diplôme : Doctorat En ligne : ../theses/physique/GHE7310.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=10925 Study of a nanostructured compound based on II-VI semiconductors (ZnS). [texte imprimé] / Khaoula Ghezali, Auteur ; Boubekeur Boudine, Directeur de thèse ; Amor Azizi, Directeur de thèse . - جامعة الإخوة منتوري قسنطينة, 2018 . - 131 f. ; 30 cm.
2 copies imprimées disponibles
Langues : Anglais (eng)
Catégories : Français - Anglais
PhysiqueTags : Electrodéposition nanostructures ZnS Mott-Schottky TRPL. الهياكل النانوية كبريت الزنك العناصر الأرضية النادرة Index. décimale : 530 Physique Résumé : This thesis deals with the elaboration and characterization of zinc sulfide (ZnS) nanostructures for photovoltaic applications. We used the electrochemical deposition method to synthesize these films, and this, for its simplicity and low cost. The deposit solution is composed of zinc sulfate and sodium thiosulfate (Na2S2O3) as sources of Zn and S, respectively. This work is devised on two part. First, the samples were prepared by varying several parameters such as zinc concentration, pH, deposition potential and time deposition. The obtained nanostructures were subjected to various characterizations such as electronic (Mott-Schottky), morphological (SEM, AFM), Structural (XRD) and optical properties (UV-Vis). The Mott-Schottky measures showed that the films have an n-type conductivity when the carrier concentration and flat band potential was strongly depend on the different parameters. The morphological characterization of the samples by AFM and SEM showed a significant change of the with topography different parameters. The structural analysis shows that the obtained films are monocrystalline, they exhibit a zinc blend structure. The preferential orientation is strongly related to the experimental parameters. Studied at the end of this part the optical results show a lower transmittance. The second part is devoted to the doping of ZnS nanostructures by rare earths (Er, Sm). An improvement of optical properties (transmittance 80%) was obtained when we increase the dopants concentration and the optical band gap increases after doping from 3.54 to 3.8 eV for both dopants. The time-resolved photoluminescence decay were used to determine the charge carrier transfer (life time) of ZnS with the Er and Sm doping.
Diplôme : Doctorat En ligne : ../theses/physique/GHE7310.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=10925 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité GHE/7310 GHE/7310 Thèse Bibliothèque principale Thèses Disponible
Titre : Theoretical and computational approach of physical properties of materials : Tension-strain relationships, Type de document : texte imprimé Auteurs : Hocine Chorfi, Auteur ; Boubekeur Boudine, Directeur de thèse ; Fahima Boudjada, Directeur de thèse Mention d'édition : 28/10/2020 Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2020 Importance : 165 f. Format : 30 cm. Note générale : 1 copies imprimées disponibles
Langues : Français (fre) Catégories : Français - Anglais
PhysiqueTags : physique: Crystallography carbure de silicium oxyde de zinc bisulfure de molybdène défaillance mécanique contrainte-déformation premiers principes théorie fonctionnelle de la densité équation spinodale carburo de silicio óxido de zinc desulfuro de molibdeno falla mecánica tensión-deformación primeros principios teoría funcional de la densidad ecuación espinodal كربید السیلیكون أكسید الزنك ثاني كبریتید المولیبدینوم الفشل المیكانیكي إجھاد الإجھاد المبادئ الأولى نظریة الكثافة الوظیفیة المعادلة اللفافة Index. décimale : 530 Physique Résumé :
Silicon carbide (SiC), Zinc oxyde (ZnO), graphite and molybdenum disulfide (MoS2) attract much interest as materials with technological applications for the development of new electronic devices, in particular the new generation of semiconductors known as Power Semiconductor Devices (PSDs) or Field Effect Transistors (FETs). One of the biggest challenges is to understand the mechanical failure that occurs in the manufacturing process of these materials as a result of the stresses induced during the heating cycles to which they are subjected. Therefore, the fundamental objective of this thesis is the evaluation and analysis in chemical-physical terms of the stress-strain relationships. From these relationships, the limit of mechanical stability of these systems can be determined. Computational simulation allow acces to these relationships in a quantitative way, thus providing information that is difficult to acces, sometimes experimentally.In this study, we present results fromfirstprinciples density functional theory calculations that quantitatively account for the response of selected covalent, ionic and layered materials to general stress conditions. In particular, we have evaluated the ideal strength along the main crystallographic directions of 3C and 2H polytypes ofSiC, hexagonal ABA stacking of graphite, ZnO and 2H-MoS2. Transverse superimposed stress on thetensile stress was taken into account in order to evaluate how the critical strength is affected by thesemulti-load conditions. In general, increasing transverse
stress from negative to positive values leads to the expected decreasing of the critical strength. Few exceptions found in the compressive stressregion correlate with the trends in the density of bonds along the directions with the unexpectedbehavior. In addition, we propose a modified spinodal equation of state able to accurately describethe calculated stress–strain curves. This analytical function is of general use and can also be appliedto experimental data anticipating critical strengths and strain values, and for providing informationon the energy stored in tensile stress processes. The first part of this Doctoral Thesis will be devoted to the presentation of the theoretical and methodological bases of the computational tools that are used in the simulations of the mechanical behavior that will be investigated in these materials. In the second part, stressstrain relationships are evaluated along relevant crystallographic directions, the ideal voltage is calculated and the results are interpreted and explained in terms of the chemical bond and the thermodynamic stability limit using the spinodal equation. The thesis will conclude with a summary of the most relevant contributions of this study.
Diplôme : Doctorat en sciences En ligne : ../theses/physique/CHO7695.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=11529 Theoretical and computational approach of physical properties of materials : Tension-strain relationships, [texte imprimé] / Hocine Chorfi, Auteur ; Boubekeur Boudine, Directeur de thèse ; Fahima Boudjada, Directeur de thèse . - 28/10/2020 . - جامعة الإخوة منتوري قسنطينة, 2020 . - 165 f. ; 30 cm.
1 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
PhysiqueTags : physique: Crystallography carbure de silicium oxyde de zinc bisulfure de molybdène défaillance mécanique contrainte-déformation premiers principes théorie fonctionnelle de la densité équation spinodale carburo de silicio óxido de zinc desulfuro de molibdeno falla mecánica tensión-deformación primeros principios teoría funcional de la densidad ecuación espinodal كربید السیلیكون أكسید الزنك ثاني كبریتید المولیبدینوم الفشل المیكانیكي إجھاد الإجھاد المبادئ الأولى نظریة الكثافة الوظیفیة المعادلة اللفافة Index. décimale : 530 Physique Résumé :
Silicon carbide (SiC), Zinc oxyde (ZnO), graphite and molybdenum disulfide (MoS2) attract much interest as materials with technological applications for the development of new electronic devices, in particular the new generation of semiconductors known as Power Semiconductor Devices (PSDs) or Field Effect Transistors (FETs). One of the biggest challenges is to understand the mechanical failure that occurs in the manufacturing process of these materials as a result of the stresses induced during the heating cycles to which they are subjected. Therefore, the fundamental objective of this thesis is the evaluation and analysis in chemical-physical terms of the stress-strain relationships. From these relationships, the limit of mechanical stability of these systems can be determined. Computational simulation allow acces to these relationships in a quantitative way, thus providing information that is difficult to acces, sometimes experimentally.In this study, we present results fromfirstprinciples density functional theory calculations that quantitatively account for the response of selected covalent, ionic and layered materials to general stress conditions. In particular, we have evaluated the ideal strength along the main crystallographic directions of 3C and 2H polytypes ofSiC, hexagonal ABA stacking of graphite, ZnO and 2H-MoS2. Transverse superimposed stress on thetensile stress was taken into account in order to evaluate how the critical strength is affected by thesemulti-load conditions. In general, increasing transverse
stress from negative to positive values leads to the expected decreasing of the critical strength. Few exceptions found in the compressive stressregion correlate with the trends in the density of bonds along the directions with the unexpectedbehavior. In addition, we propose a modified spinodal equation of state able to accurately describethe calculated stress–strain curves. This analytical function is of general use and can also be appliedto experimental data anticipating critical strengths and strain values, and for providing informationon the energy stored in tensile stress processes. The first part of this Doctoral Thesis will be devoted to the presentation of the theoretical and methodological bases of the computational tools that are used in the simulations of the mechanical behavior that will be investigated in these materials. In the second part, stressstrain relationships are evaluated along relevant crystallographic directions, the ideal voltage is calculated and the results are interpreted and explained in terms of the chemical bond and the thermodynamic stability limit using the spinodal equation. The thesis will conclude with a summary of the most relevant contributions of this study.
Diplôme : Doctorat en sciences En ligne : ../theses/physique/CHO7695.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=11529 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité CHO/7695 CHO/7695 Thèse Bibliothèque principale Thèses Disponible
