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Partager le résultat de cette recherche Interroger des sources externesEtude des propriétés structurales et optiques de nano-cristaux semi-conducteurs à grand gap synthétisés par voie sol-gel modifiée / Soumia Haya
Titre : Etude des propriétés structurales et optiques de nano-cristaux semi-conducteurs à grand gap synthétisés par voie sol-gel modifiée Type de document : texte imprimé Auteurs : Soumia Haya, Auteur ; Ouahiba Halimi, Directeur de thèse Editeur : Constantine : Université Mentouri Constantine Année de publication : 2010 Importance : 99 f. Format : 30 cm. Note générale : 2 copies imprimées disponibles
Langues : Français (fre) Catégories : Français - Anglais
PhysiqueTags : Couches Minces ZnO,TiO2 irradiation UV diffraction des rayons X absorption optique photoluminescence Sol-Gel Dip-Cointing Thin Film UV light X-ray diffraction Optical absorption Photoluminescence ?????? ?????? UV ?????? RX ?????? ??????? TiO ? 2 ZnO ????? 2
. Dip – Coating ???????? ?????????? ????? ??? ?????Index. décimale : 530 Physique Résumé : This thesis concerns the development and characterization of thin films of ZnO and TiO2, which were conducted at temperatures close to room temperature using the sol-gel method with a deposition technique ""Dip Coating."" The Both
samples were prepared by two different solutions: the first is to add the precursor of zinc acetate dihydrate and the solvent 2-methoxyethanol with monoethanolamine as a stabilizer, while the second is to dissolve the titaniaume IV propoxide in ethanol (solvent) with the addition of HCl as catalyst.
Structural characterization of thin films of ZnO and TiO2 was carried out by X-ray diffraction. It confirmed first, the formation of crystallites for both samples irradiated by UV light for 84 hours and 155 hours in the case of ZnO and TiO2, respectively, and secondly to determine their crystal structures and their small size
does not exceed a few of nanometers.
Characterization by measurement of optical absorption in the UV – visible domain, showed a shift of absorption edge for ZnO and TiO2 layers to high energies (short wavelengths) compared to that of bulk crystal of the latter two. This
discrepancy is due to quantum confinement effect induced by size reduction.
A second optical characterization by photoluminescence measurement showed that the samples prepared exhibit intense emission bands in the visible and near UV.
This observation led us to practical applications in area of optic and photovoltaic.
Diplôme : Magistère En ligne : ../theses/physique/HAY6698.pdf Format de la ressource électronique : Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=9925 Etude des propriétés structurales et optiques de nano-cristaux semi-conducteurs à grand gap synthétisés par voie sol-gel modifiée [texte imprimé] / Soumia Haya, Auteur ; Ouahiba Halimi, Directeur de thèse . - Constantine : Université Mentouri Constantine, 2010 . - 99 f. ; 30 cm.
2 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
PhysiqueTags : Couches Minces ZnO,TiO2 irradiation UV diffraction des rayons X absorption optique photoluminescence Sol-Gel Dip-Cointing Thin Film UV light X-ray diffraction Optical absorption Photoluminescence ?????? ?????? UV ?????? RX ?????? ??????? TiO ? 2 ZnO ????? 2
. Dip – Coating ???????? ?????????? ????? ??? ?????Index. décimale : 530 Physique Résumé : This thesis concerns the development and characterization of thin films of ZnO and TiO2, which were conducted at temperatures close to room temperature using the sol-gel method with a deposition technique ""Dip Coating."" The Both
samples were prepared by two different solutions: the first is to add the precursor of zinc acetate dihydrate and the solvent 2-methoxyethanol with monoethanolamine as a stabilizer, while the second is to dissolve the titaniaume IV propoxide in ethanol (solvent) with the addition of HCl as catalyst.
Structural characterization of thin films of ZnO and TiO2 was carried out by X-ray diffraction. It confirmed first, the formation of crystallites for both samples irradiated by UV light for 84 hours and 155 hours in the case of ZnO and TiO2, respectively, and secondly to determine their crystal structures and their small size
does not exceed a few of nanometers.
Characterization by measurement of optical absorption in the UV – visible domain, showed a shift of absorption edge for ZnO and TiO2 layers to high energies (short wavelengths) compared to that of bulk crystal of the latter two. This
discrepancy is due to quantum confinement effect induced by size reduction.
A second optical characterization by photoluminescence measurement showed that the samples prepared exhibit intense emission bands in the visible and near UV.
This observation led us to practical applications in area of optic and photovoltaic.
Diplôme : Magistère En ligne : ../theses/physique/HAY6698.pdf Format de la ressource électronique : Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=9925 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité HAY/6698 HAY/6698 Thèse Bibliothèque principale Thèses Disponible
Titre : Caractérisation structurale et optique des nanocristaux des semi-conducteurs Ga As et TiO2 inclus dans les monocristaux de KCL et de KBr Type de document : texte imprimé Auteurs : Nadia Berroual, Auteur ; M. Sebais, Directeur de thèse Editeur : Constantine : Université Mentouri Constantine Année de publication : 2005 Importance : 74 f. Format : 31 cm Note générale : 2 copies imprimées disponibles Langues : Français (fre) Catégories : Français - Anglais
PhysiqueTags : Croissance cristalline Absorption optique Photoluminescence Diffraction X Nanocristaux Semiconducteurs GaAs et TiO2
Nanocrystals Semiconductors GaAs and TiO2 Crystal Growth X Ray Diffraction Optical Absorption ?????????? ? ??? ? ??????? GaAs? TiO2??? ????? ?????? X??????
???? ?????? ????Index. décimale : 530 Physique Résumé : This work contains many and different results wich concerne elaboration and structural and optical carcterisationof nanocrystals of GaAs and TiO2 embedded in two different matrixes of alkali halides of KCl and KBr.
The elaboration of the single crystals KCl and KBr was made bye pooling with Czochralski technique. The doping of these single crystals was realised during the growth of single crystals.
Structural carcterisation with Xray diffraction, revealed the incorporation of nanocristallites of semiconductors GaAs and TiO2 in crystal matrixes.
A caracterisation bye measurement of optical absorption in the range of UV-Visible (were KBr and KCl are transparant ) show a shift of the absorption edge of semiconductors GaAs and TiO2 to short long –waves ( so high energies) relatively to the absorption edge of large crystals of the same semiconductors. This shift is caused bye the size reduction effect, also of the edge shift, we can see on the absorption spectra, pics that was considered as excitonic pics.
Nanocrystals size of GaAs and TiO2 semiconductors embedded in single crystals of KBr and KCl was estimated using the mass effective model as:
In KBr R (GaAs) = 4.03 nm R(TiO2) = 2.73 nm
In KCl R (GaAs) = 4.03 nm R(TiO2) = 3.22 nm
A second optical caracterisation bye photoluminescence mesuerement show that the elaborated samples present luminescence bands in the visible range, wich can gave the possibility to considere theme as optical actif mediums.Diplôme : Magistère En ligne : ../theses/physique/BER4355.pdf Format de la ressource électronique : Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=3331 Caractérisation structurale et optique des nanocristaux des semi-conducteurs Ga As et TiO2 inclus dans les monocristaux de KCL et de KBr [texte imprimé] / Nadia Berroual, Auteur ; M. Sebais, Directeur de thèse . - Constantine : Université Mentouri Constantine, 2005 . - 74 f. ; 31 cm.
2 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
PhysiqueTags : Croissance cristalline Absorption optique Photoluminescence Diffraction X Nanocristaux Semiconducteurs GaAs et TiO2
Nanocrystals Semiconductors GaAs and TiO2 Crystal Growth X Ray Diffraction Optical Absorption ?????????? ? ??? ? ??????? GaAs? TiO2??? ????? ?????? X??????
???? ?????? ????Index. décimale : 530 Physique Résumé : This work contains many and different results wich concerne elaboration and structural and optical carcterisationof nanocrystals of GaAs and TiO2 embedded in two different matrixes of alkali halides of KCl and KBr.
The elaboration of the single crystals KCl and KBr was made bye pooling with Czochralski technique. The doping of these single crystals was realised during the growth of single crystals.
Structural carcterisation with Xray diffraction, revealed the incorporation of nanocristallites of semiconductors GaAs and TiO2 in crystal matrixes.
A caracterisation bye measurement of optical absorption in the range of UV-Visible (were KBr and KCl are transparant ) show a shift of the absorption edge of semiconductors GaAs and TiO2 to short long –waves ( so high energies) relatively to the absorption edge of large crystals of the same semiconductors. This shift is caused bye the size reduction effect, also of the edge shift, we can see on the absorption spectra, pics that was considered as excitonic pics.
Nanocrystals size of GaAs and TiO2 semiconductors embedded in single crystals of KBr and KCl was estimated using the mass effective model as:
In KBr R (GaAs) = 4.03 nm R(TiO2) = 2.73 nm
In KCl R (GaAs) = 4.03 nm R(TiO2) = 3.22 nm
A second optical caracterisation bye photoluminescence mesuerement show that the elaborated samples present luminescence bands in the visible range, wich can gave the possibility to considere theme as optical actif mediums.Diplôme : Magistère En ligne : ../theses/physique/BER4355.pdf Format de la ressource électronique : Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=3331 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité BER/4355 BER/4355 Thèse Bibliothèque principale Thèses Disponible
Titre : Elaboration et caractérisation de matériaux composites à base des nanoparticules du semi-conducteur CuO et de l’oxyde de terre rare Dy2O3 dispersées dans les matrices diélectriques KBr, KCl et NaCl. Type de document : texte imprimé Auteurs : Samiya Addala, Auteur ; O. Halimi, Directeur de thèse Editeur : Constantine : Université Mentouri Constantine Année de publication : 2015 Importance : 106 f. Format : 30 cm. Note générale : 2 copies imprimées disponibles
Langues : Français (fre) Catégories : Français - Anglais
PhysiqueTags : NaCl KCl KBr semiconducteur (CuO) oxyde de terre rare (Dy2O3) Czochralski DRX FT-IR µ-Ramn MEB-EDX UV-Visible photoluminescence semiconductor (CuO) rare earth oxide (Dy2O3) XRD IR ?-Ramn Uvi-Vis ???????? ??????????? ??? ?????? )CuO( ??????)Dy2O3) ????? ????????? ?????? ???? X ????????
?????? ???? ????? ? ?????? ?? ??? ??????? ?????? ?????????? ?????? MEBIndex. décimale : 530 Physique Résumé : Elaboration and characterization of composite materials based on nanoparticles of the semiconductor CuO and the rare earth oxide Dy2O3 dispersed in the dielectric matrix of KBr, KCl and NaCl In this work copper oxide (CuO) and dysprosium oxide (Dy2O3) nanocrystals doped KBr, KCl and NaCl single crystals have been grown by Czochralski (Cz) method.
The effects of doping on the structural and optical properties of the host matrices have been studied.
The structural studies of samples were performed by XRD, μ-Raman, IR spectroscopy, scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX).The treatment of XRD spectrum confirms the existence of crystallites of dopants (Sb2O3 and Y2O3) in the nanometer regime;Studies by μ-Raman and IR confirmed the
presence of chemical bonds Dy—Oand Cu—O in the different matrices.
The morphological study using the scanning electron microscope (SEM) shows that the micron grains scattered on the surface. The microscopic size of these aggregates is due to the fact that the nanocrystals have a tendency to reduce its free energy (Gibbs energy) of surface. The energy dispersive X-ray analysis (EDX) spectrum indicates that
the NaCl:CuO single crystal has a very high purity.
The optical absorption and photoluminescence shows that the optical gaps of the crystallites (CuO and Dy2O3) have been shifted to the high energy due to the quantum confinement effect of the charges.
The samples have important intense luminescence properties in the ultraviolet range. This feature makes these materials candidates which might come in the manufacture of components for optical systems using shorter wavelengths.
Diplôme : Doctorat en sciences En ligne : ../theses/physique/ADD6746.pdf Format de la ressource électronique : Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=9870 Elaboration et caractérisation de matériaux composites à base des nanoparticules du semi-conducteur CuO et de l’oxyde de terre rare Dy2O3 dispersées dans les matrices diélectriques KBr, KCl et NaCl. [texte imprimé] / Samiya Addala, Auteur ; O. Halimi, Directeur de thèse . - Constantine : Université Mentouri Constantine, 2015 . - 106 f. ; 30 cm.
2 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
PhysiqueTags : NaCl KCl KBr semiconducteur (CuO) oxyde de terre rare (Dy2O3) Czochralski DRX FT-IR µ-Ramn MEB-EDX UV-Visible photoluminescence semiconductor (CuO) rare earth oxide (Dy2O3) XRD IR ?-Ramn Uvi-Vis ???????? ??????????? ??? ?????? )CuO( ??????)Dy2O3) ????? ????????? ?????? ???? X ????????
?????? ???? ????? ? ?????? ?? ??? ??????? ?????? ?????????? ?????? MEBIndex. décimale : 530 Physique Résumé : Elaboration and characterization of composite materials based on nanoparticles of the semiconductor CuO and the rare earth oxide Dy2O3 dispersed in the dielectric matrix of KBr, KCl and NaCl In this work copper oxide (CuO) and dysprosium oxide (Dy2O3) nanocrystals doped KBr, KCl and NaCl single crystals have been grown by Czochralski (Cz) method.
The effects of doping on the structural and optical properties of the host matrices have been studied.
The structural studies of samples were performed by XRD, μ-Raman, IR spectroscopy, scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX).The treatment of XRD spectrum confirms the existence of crystallites of dopants (Sb2O3 and Y2O3) in the nanometer regime;Studies by μ-Raman and IR confirmed the
presence of chemical bonds Dy—Oand Cu—O in the different matrices.
The morphological study using the scanning electron microscope (SEM) shows that the micron grains scattered on the surface. The microscopic size of these aggregates is due to the fact that the nanocrystals have a tendency to reduce its free energy (Gibbs energy) of surface. The energy dispersive X-ray analysis (EDX) spectrum indicates that
the NaCl:CuO single crystal has a very high purity.
The optical absorption and photoluminescence shows that the optical gaps of the crystallites (CuO and Dy2O3) have been shifted to the high energy due to the quantum confinement effect of the charges.
The samples have important intense luminescence properties in the ultraviolet range. This feature makes these materials candidates which might come in the manufacture of components for optical systems using shorter wavelengths.
Diplôme : Doctorat en sciences En ligne : ../theses/physique/ADD6746.pdf Format de la ressource électronique : Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=9870 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité ADD/6746 ADD/6746 Thèse Bibliothèque principale Thèses Disponible
Titre : Elaboration et caractérisation de nanocomposites hybrides : Oxydes métalliques/polymères Type de document : texte imprimé Auteurs : Bariza Troudi, Auteur ; Ouahiba Halimi, Directeur de thèse Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2017 Importance : 121 f. Format : 30 cm. Note générale : 2 copies imprimées disponibles
Langues : Français (fre) Catégories : Français - Anglais
PhysiqueTags : Synthèse hydrothermale Nanocomposites Films minces CuO/PS CuO/PVC PbO/PS PbO/PVC DRX FT-IR Raman AFM Absorption UV-Visible photoluminescence Hydrothermal synthesis thin films UV-Visible Absorption ?????? ?????? ????? ????? ???????? ??? ????????- ???? ???????? ?????? Index. décimale : 530 Physique Résumé : Thin films of metal oxides/polymers nanocomposites were deposited on glass substrates by Spin-Coating and Dip-Coating techniques. The nanocomposites were elaborated by inserting, in the matrices of polystyrene (PS) and polyvinyl chloride (PVC) polymers, of nanoparticles of metal oxides such as copper oxide (CuO) and lead oxide (PbO). The nanoparticles of semiconductor CuO and PbO were synthesized beforehand by the hydrothermal method. The xray diffraction characterization of the obtained powders have revealed a monoclinic phase for CuO crystallites and an orthorhombic phase for PbO. The size of the crystallites of the two semiconductors is of a nanometic order. Calcul the of gap energy indicate a shift towards high energies compared to massive crystals. This shift is due to the effect of the quantum confinement induced by the nanometric size of the crystallites of the semiconductors. These nanocrystals are used for the preparation of the nanocomposites of CuO/PS, CuO/PVC, PbO/PS and PbO/PVC by
simple insertion of CuO and PbO nanoparticles in the PS and PVC polymers. The analysis of the elaborated nanocomposites by X-ray diffraction has allowed to notice the incorporation of the CuO and PbO crystallites into the PS and PVC polymers matrixes and analysis by Raman and infrared spectroscopies has confirmed the presence of CuO and PbO crystallites in the PS and PVC matrixes by revealing specific vibration modes to the Cu-O and Pb-O bonds. The surface morphology and topography of thin films of nanocomposites were highlighted with the help of atomic force microscopy (AFM) and have shown homogeneous dispersion of CuO and PbO crystallites and a low surface roughness. the characterization by measurement of the optical absorption in the UV-Visible domain allows to observe the increase in optical absorption which is attributed to CuO and PbO nanocrystallites because PS and PVC are optically transparent in the UV-Visible domain. A shift of the gap energy of the nanocomposites compared with the gap energy of the pure polymers and the massive crystallites of CuO and PbO was observed. This variation in gap energy is the result of the new optical behavior of the prepared nanocomposites.
The optical characterization by the measure of the photoluminescence has shown that the elaborated samples present intense luminescence bands in the visible range, hence the possibility of consider these matrices as optically active media and can be used for the making devices of specific optics properties.
Diplôme : Doctorat en sciences En ligne : ../theses/physique/TRO7142.pdf Format de la ressource électronique : Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=10460 Elaboration et caractérisation de nanocomposites hybrides : Oxydes métalliques/polymères [texte imprimé] / Bariza Troudi, Auteur ; Ouahiba Halimi, Directeur de thèse . - [S.l.] : جامعة الإخوة منتوري قسنطينة, 2017 . - 121 f. ; 30 cm.
2 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
PhysiqueTags : Synthèse hydrothermale Nanocomposites Films minces CuO/PS CuO/PVC PbO/PS PbO/PVC DRX FT-IR Raman AFM Absorption UV-Visible photoluminescence Hydrothermal synthesis thin films UV-Visible Absorption ?????? ?????? ????? ????? ???????? ??? ????????- ???? ???????? ?????? Index. décimale : 530 Physique Résumé : Thin films of metal oxides/polymers nanocomposites were deposited on glass substrates by Spin-Coating and Dip-Coating techniques. The nanocomposites were elaborated by inserting, in the matrices of polystyrene (PS) and polyvinyl chloride (PVC) polymers, of nanoparticles of metal oxides such as copper oxide (CuO) and lead oxide (PbO). The nanoparticles of semiconductor CuO and PbO were synthesized beforehand by the hydrothermal method. The xray diffraction characterization of the obtained powders have revealed a monoclinic phase for CuO crystallites and an orthorhombic phase for PbO. The size of the crystallites of the two semiconductors is of a nanometic order. Calcul the of gap energy indicate a shift towards high energies compared to massive crystals. This shift is due to the effect of the quantum confinement induced by the nanometric size of the crystallites of the semiconductors. These nanocrystals are used for the preparation of the nanocomposites of CuO/PS, CuO/PVC, PbO/PS and PbO/PVC by
simple insertion of CuO and PbO nanoparticles in the PS and PVC polymers. The analysis of the elaborated nanocomposites by X-ray diffraction has allowed to notice the incorporation of the CuO and PbO crystallites into the PS and PVC polymers matrixes and analysis by Raman and infrared spectroscopies has confirmed the presence of CuO and PbO crystallites in the PS and PVC matrixes by revealing specific vibration modes to the Cu-O and Pb-O bonds. The surface morphology and topography of thin films of nanocomposites were highlighted with the help of atomic force microscopy (AFM) and have shown homogeneous dispersion of CuO and PbO crystallites and a low surface roughness. the characterization by measurement of the optical absorption in the UV-Visible domain allows to observe the increase in optical absorption which is attributed to CuO and PbO nanocrystallites because PS and PVC are optically transparent in the UV-Visible domain. A shift of the gap energy of the nanocomposites compared with the gap energy of the pure polymers and the massive crystallites of CuO and PbO was observed. This variation in gap energy is the result of the new optical behavior of the prepared nanocomposites.
The optical characterization by the measure of the photoluminescence has shown that the elaborated samples present intense luminescence bands in the visible range, hence the possibility of consider these matrices as optically active media and can be used for the making devices of specific optics properties.
Diplôme : Doctorat en sciences En ligne : ../theses/physique/TRO7142.pdf Format de la ressource électronique : Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=10460 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité TRO/7142 TRO/7142 Thèse Bibliothèque principale Thèses Disponible 
Titre : Elaboration et caractérisation structurale et optique des nanocristaux du semiconducteur Sb2O3 et de l'oxyde Y2O3 dispersés dans les matrices cristallines des halogénures alcalins KBr, KCl et NaCl Type de document : texte imprimé Auteurs : Lazhar Bouhdjer, Auteur ; M. Sebais, Directeur de thèse Editeur : constantine [Algérie] : Université Constantine 1 Année de publication : 2013 Importance : 93 f. Format : 30 cm. Note générale : 2 copies imprimées disponibles Langues : Français (fre) Catégories : Français - Anglais
PhysiqueTags : semi-conducteur Sb2O3 oxyde de terre rare Y2O3 Czochralski DRX FT-IR ?-Ramn absorption UV-Visible photoluminescence semiconductor (Sb2O3) rare earth oxide (Y2O3) XRD IR ?-
Ramn Uvi-Vis ???????? ???????????
????? ????????? ???????? ?????? ???? ????? ? ?????? ?? ??? ??????? ?????? ?????????? ?????? MEB (Sb2O3)??? ?????? (Y2O3)??????
?????? ?????? XIndex. décimale : 530 Physique Résumé : Preparation and structural and optical characterization of semiconductor nanocrystals
of Sb2O3 and Y2O3 oxide dispersed in a crystalline matrices of alkali halides KBr, KCl
and NaCl.
In this work antimony oxide (Sb2O3) and yttrium oxide (Y2O3) nanocrystals doped KBr, KCl and NaCl single crystals have been grown by Czochralski (Cz) method.
The effects of doping on the structural and optical properties of the host matrices have
been studied.
The structural studies of samples were performed by XRD, μ-Raman, IR spectroscopy, scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). The treatment of XRD spectrum confirms the existence of crystallites of dopants (Sb2O3 and Y2O3) in the nanometer regime; on the other hand, the existence of the stable monoclinic phase crystallites (Y2O3) under atmospheric conditions reconfirms presence of (Y2O3) in nanoscale.
Studies by μ-Raman and IR confirmed the presence of chemical bonds Y—O and Sb—O in the different matrices.
The morphological study using the scanning electron microscope (SEM) shows that the micron grains scattered on the surface. The volume of these aggregates is due to the fact that the nanocrystals have a tendency to reduce its free energy (Gibbs energy) of surface.
The optical absorption and photoluminescence shows that the optical gaps of the crystallites (Sb2O3 and Y2O3) have been shifted to the high energy due to the quantum confinement effect of the charges.
The samples have important intense luminescence properties in the ultraviolet range. This feature makes these materials candidates which might come in the manufacture of components for optical systems using shorter wavelengths.Diplôme : Doctorat en sciences En ligne : ../theses/physique/BOU6378.pdf Format de la ressource électronique : Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=9379 Elaboration et caractérisation structurale et optique des nanocristaux du semiconducteur Sb2O3 et de l'oxyde Y2O3 dispersés dans les matrices cristallines des halogénures alcalins KBr, KCl et NaCl [texte imprimé] / Lazhar Bouhdjer, Auteur ; M. Sebais, Directeur de thèse . - constantine (Route ain el bey, Algérie) : Université Constantine 1, 2013 . - 93 f. ; 30 cm.
2 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
PhysiqueTags : semi-conducteur Sb2O3 oxyde de terre rare Y2O3 Czochralski DRX FT-IR ?-Ramn absorption UV-Visible photoluminescence semiconductor (Sb2O3) rare earth oxide (Y2O3) XRD IR ?-
Ramn Uvi-Vis ???????? ???????????
????? ????????? ???????? ?????? ???? ????? ? ?????? ?? ??? ??????? ?????? ?????????? ?????? MEB (Sb2O3)??? ?????? (Y2O3)??????
?????? ?????? XIndex. décimale : 530 Physique Résumé : Preparation and structural and optical characterization of semiconductor nanocrystals
of Sb2O3 and Y2O3 oxide dispersed in a crystalline matrices of alkali halides KBr, KCl
and NaCl.
In this work antimony oxide (Sb2O3) and yttrium oxide (Y2O3) nanocrystals doped KBr, KCl and NaCl single crystals have been grown by Czochralski (Cz) method.
The effects of doping on the structural and optical properties of the host matrices have
been studied.
The structural studies of samples were performed by XRD, μ-Raman, IR spectroscopy, scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). The treatment of XRD spectrum confirms the existence of crystallites of dopants (Sb2O3 and Y2O3) in the nanometer regime; on the other hand, the existence of the stable monoclinic phase crystallites (Y2O3) under atmospheric conditions reconfirms presence of (Y2O3) in nanoscale.
Studies by μ-Raman and IR confirmed the presence of chemical bonds Y—O and Sb—O in the different matrices.
The morphological study using the scanning electron microscope (SEM) shows that the micron grains scattered on the surface. The volume of these aggregates is due to the fact that the nanocrystals have a tendency to reduce its free energy (Gibbs energy) of surface.
The optical absorption and photoluminescence shows that the optical gaps of the crystallites (Sb2O3 and Y2O3) have been shifted to the high energy due to the quantum confinement effect of the charges.
The samples have important intense luminescence properties in the ultraviolet range. This feature makes these materials candidates which might come in the manufacture of components for optical systems using shorter wavelengths.Diplôme : Doctorat en sciences En ligne : ../theses/physique/BOU6378.pdf Format de la ressource électronique : Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=9379 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité BOU/6378 BOU/6378 Thèse Bibliothèque principale Thèses Disponible Documents numériques
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