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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 Etude de l’influence des effets des elements lourds sur les proprietes physique des couches minces de TIO2 / Fouzia Abbas
Titre : Etude de l’influence des effets des elements lourds sur les proprietes physique des couches minces de TIO2 Type de document : texte imprimé Auteurs : Fouzia Abbas, Auteur ; Rabah Bensaha, Directeur de thèse Editeur : Constantine : Université Mentouri Constantine Année de publication : 2015 Importance : 190 f. Format : 30 cm. Note générale : 2 copies imprimées disponibles
Langues : Français (fre) Catégories : Français - Anglais
PhysiqueTags : Sol-Gel Thin films nanstructurs TiO2 doped Mercury Lead Zinc.
Couches minces Nanostructures TiO2 dopé Mercure Plomb شرائح رقيقة مطعم TiO2 الزئبق الرصاص الزنكIndex. décimale : 530 Physique Résumé : This work is focused on preparation and characterization of thin layers of titanium oxide (TiO2) undoped and doped with heavy elements such as mercury, lead and zinc prepared by sol-gel method and deposited on various substrates (glass, silicon and ITO). In this study we used various investigative techniques: XRD, Raman spectroscopy, FTIR, UVVisible-NIR, Photoluminescence, Profilo-meter, SEM, AFM and spectroscopy Electrochemical potential.
DSC and XRD results show that the doping TiO2 xerogels with Hg and Pb accelerated crystallization compare of these doping with Zn which causes a delay of the crystallization of titanium oxide. The doped thin films obtained crystallize at low temperature on the titanium oxide structures, but with the increasing annealing temperature we distinguish the appearance of new phases corresponding to the doping elements this according to the type dopant. Raman and FTIR spectra confirm the results obtained by XRD and Raman spectroscopy by the appearance of vibrational bands corresponding to the same phases.
The micrographs of doped thin films show a morphology consisting of various nanostructures varied depending on the nature of the dopant and the annealing temperature.
Thin films of TiO2 doped Hg crystallizes in the form of nanoparticles, nano-sheets and nanotubes, the doping by Pb crystallizes with nano-structure of nonporous, nanotubes while doping with zinc shows the crystallization of the films with porous, nanowires and nanorodes structure .The grain size increases as the annealing temperature increases. The AFM images
correlates the observations of SEM are composed of many nanostructures with high density.
Characterizations by UV-Visible-NIR spectrophotometry, ellipsométerie and the PL spectroscopy show that the nature of dopant and the annealing temperature and the thickness of films can improve the optical properties of TiO2. Firstly, the elevation of these parameters increases the transmittance, the refractive index and decreases the optical gap; on the other hand, the doping effect causes a shift to larger lengths. This discrepancy confirmed the results obtained by photoluminescence (PL).
Characterizations I = f (v) of the thin films shows that the doping improve the properties of thin films they can be used in different application such as gas sensing and the photovoltaic field.
Diplôme : Doctorat en sciences En ligne : ../theses/physique/ABB6781.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=9844 Etude de l’influence des effets des elements lourds sur les proprietes physique des couches minces de TIO2 [texte imprimé] / Fouzia Abbas, Auteur ; Rabah Bensaha, Directeur de thèse . - Constantine : Université Mentouri Constantine, 2015 . - 190 f. ; 30 cm.
2 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
PhysiqueTags : Sol-Gel Thin films nanstructurs TiO2 doped Mercury Lead Zinc.
Couches minces Nanostructures TiO2 dopé Mercure Plomb شرائح رقيقة مطعم TiO2 الزئبق الرصاص الزنكIndex. décimale : 530 Physique Résumé : This work is focused on preparation and characterization of thin layers of titanium oxide (TiO2) undoped and doped with heavy elements such as mercury, lead and zinc prepared by sol-gel method and deposited on various substrates (glass, silicon and ITO). In this study we used various investigative techniques: XRD, Raman spectroscopy, FTIR, UVVisible-NIR, Photoluminescence, Profilo-meter, SEM, AFM and spectroscopy Electrochemical potential.
DSC and XRD results show that the doping TiO2 xerogels with Hg and Pb accelerated crystallization compare of these doping with Zn which causes a delay of the crystallization of titanium oxide. The doped thin films obtained crystallize at low temperature on the titanium oxide structures, but with the increasing annealing temperature we distinguish the appearance of new phases corresponding to the doping elements this according to the type dopant. Raman and FTIR spectra confirm the results obtained by XRD and Raman spectroscopy by the appearance of vibrational bands corresponding to the same phases.
The micrographs of doped thin films show a morphology consisting of various nanostructures varied depending on the nature of the dopant and the annealing temperature.
Thin films of TiO2 doped Hg crystallizes in the form of nanoparticles, nano-sheets and nanotubes, the doping by Pb crystallizes with nano-structure of nonporous, nanotubes while doping with zinc shows the crystallization of the films with porous, nanowires and nanorodes structure .The grain size increases as the annealing temperature increases. The AFM images
correlates the observations of SEM are composed of many nanostructures with high density.
Characterizations by UV-Visible-NIR spectrophotometry, ellipsométerie and the PL spectroscopy show that the nature of dopant and the annealing temperature and the thickness of films can improve the optical properties of TiO2. Firstly, the elevation of these parameters increases the transmittance, the refractive index and decreases the optical gap; on the other hand, the doping effect causes a shift to larger lengths. This discrepancy confirmed the results obtained by photoluminescence (PL).
Characterizations I = f (v) of the thin films shows that the doping improve the properties of thin films they can be used in different application such as gas sensing and the photovoltaic field.
Diplôme : Doctorat en sciences En ligne : ../theses/physique/ABB6781.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=9844 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité ABB/6781 ABB/6781 Thèse Bibliothèque principale Thèses Disponible
Titre : دراسة البنى النانومترية لأكسيد التيتانيوم : تطبيق الكهروكيميائية الضوئية Type de document : texte imprimé Auteurs : نجاح صبتي, Auteur ; عاشور سليمان, Directeur de thèse Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2015 Importance : 133 ورقة. Format : 30 سم. Langues : Arabe (ara) Catégories : Arabe
الفيزياءTags : nanostructures nanofils nanotubes Nanofeuilles nanofibres anodisation hydrothermique immersion TiO2 Fe2O3-TiO2 Fe-BaTiO3 CaTiO3-TiO2 photoélectro-chimique ."
nanowires Nanoleafs anodization, hydrothermal, immersion, photoelectrochemical
البنى النانومترية الأسلاك الأنابيب الأوراق الألياف الأكسدة المصعدية المعالجة
الحرارية المائية الغمر الكهروكيميائية الضوئيةIndex. décimale : 530 الفيزياء Résumé : In this work, the preparation of different TiO2 nanostructures and their functionalization by simple methods such as anodization and hydrothermal was undertaken.
Different techniques of analysis have been used to characterize the preparedlayers of TiO2 nanostructures on Ti substrate and related compounds. These are X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), Raman spectroscopy, UV-Visible spectroscopyandX-ray Photoelectron Spectroscopy (XPS).
Anatase and rutile TiO2 in various nanostructured forms were obtained (Nanotubes, nanofibers, nanoleafs and nanowires) and analyzed. Some of these nanostructures, particularly TiO2 nanotubes and nanofibers were successfully decorated with iron oxide (Fe2O3) phase, barium titanate (BaTiO3), and calcium titante(CaTiO3) nanoparticles using various methods (hydrothermal, impregnation, and rapid flame heating).The morphology of these nanostructures considerably changed with the hydrothermal processing temperature and time. The obtained nanostructures were heat treated at different treatments both under air and vacuum in order to change their content in oxygen vacancies. Photoelectrochemical testsof the obtained various nanostructures of TiO2heat treated at 450 °C under air and 300 °C under vacuum demonstrate that TiO2 nanoleafs and nanowires have the largest photoelectrochemical currentfor samples that are treated under air. Heat treatment under vacuum was successful only in the case of TiO2 nanofibers.
Diplôme : Doctorat en sciences En ligne : ../theses/physique/ASOB4046.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=9991 دراسة البنى النانومترية لأكسيد التيتانيوم : تطبيق الكهروكيميائية الضوئية [texte imprimé] / نجاح صبتي, Auteur ; عاشور سليمان, Directeur de thèse . - جامعة الإخوة منتوري قسنطينة, 2015 . - 133 ورقة. ; 30 سم.
Langues : Arabe (ara)
Catégories : Arabe
الفيزياءTags : nanostructures nanofils nanotubes Nanofeuilles nanofibres anodisation hydrothermique immersion TiO2 Fe2O3-TiO2 Fe-BaTiO3 CaTiO3-TiO2 photoélectro-chimique ."
nanowires Nanoleafs anodization, hydrothermal, immersion, photoelectrochemical
البنى النانومترية الأسلاك الأنابيب الأوراق الألياف الأكسدة المصعدية المعالجة
الحرارية المائية الغمر الكهروكيميائية الضوئيةIndex. décimale : 530 الفيزياء Résumé : In this work, the preparation of different TiO2 nanostructures and their functionalization by simple methods such as anodization and hydrothermal was undertaken.
Different techniques of analysis have been used to characterize the preparedlayers of TiO2 nanostructures on Ti substrate and related compounds. These are X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), Raman spectroscopy, UV-Visible spectroscopyandX-ray Photoelectron Spectroscopy (XPS).
Anatase and rutile TiO2 in various nanostructured forms were obtained (Nanotubes, nanofibers, nanoleafs and nanowires) and analyzed. Some of these nanostructures, particularly TiO2 nanotubes and nanofibers were successfully decorated with iron oxide (Fe2O3) phase, barium titanate (BaTiO3), and calcium titante(CaTiO3) nanoparticles using various methods (hydrothermal, impregnation, and rapid flame heating).The morphology of these nanostructures considerably changed with the hydrothermal processing temperature and time. The obtained nanostructures were heat treated at different treatments both under air and vacuum in order to change their content in oxygen vacancies. Photoelectrochemical testsof the obtained various nanostructures of TiO2heat treated at 450 °C under air and 300 °C under vacuum demonstrate that TiO2 nanoleafs and nanowires have the largest photoelectrochemical currentfor samples that are treated under air. Heat treatment under vacuum was successful only in the case of TiO2 nanofibers.
Diplôme : Doctorat en sciences En ligne : ../theses/physique/ASOB4046.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=9991 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité صبت/4046 صبت/4046 Thèse Bibliothèque principale Thèses Disponible
