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Auteur Abderrahmane Chaieb |
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Titre : Caractérisation structurale et optique De nanocristaux de ZnO Type de document : texte imprimé Auteurs : Abdelghani Bouabdallah, Auteur ; Abderrahmane Chaieb, Directeur de thèse Editeur : constantine [Algérie] : Université Constantine 1 Année de publication : 2013 Importance : 62 f. Format : 30 cm. Note générale : 2 copies imprimées disponibles Langues : Français (fre) Catégories : Français - Anglais
PhysiqueTags : Nano composite PMMA / ZnO les rayons X RX absorption optique émission optique- methode soi-gel spin coating X-rays X-ray optical absorption optical emission - so- gel method الامتصاص الضوئي الاتبعاث الفوتوضوئي طریقة صول-جال- RX الاشعة السینیة PMMA/ZNO رقائق نانو المركب Index. décimale : 530 Physique Résumé : This work to study the structural and optical ZnO nanocrystals
For the preparation of nano- zinc oxide was confused by Material:
LaCetate Zinc dihydrate , citric acid
For the preparation of nano ZnO by material : Zinc LaCetate dihydrate , citric acid
For the preparation of thin film nano composite material was :
, The nano ZnO powder , THF ( tetrahydrofuran ) , the léthanol PMMA After preparing thin layer were placed under a UV radiation Structural study of this course are made by thin film X-ray diffraction to determine the size of nanoscale crystals ZNO
Preliminary study using the optical absorption in the UV range of the following thin film showed absorption edge shift to higher energies and this is due to the small size of the nanocrystals ZNO The study by the program that the samples his boots intense emission in the , emission of visible and near UV makes this material prepared from the elements eligible for the use of applications in the field of optical and electrical .Diplôme : Magistère En ligne : ../theses/physique/BOU6464.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=9502 Caractérisation structurale et optique De nanocristaux de ZnO [texte imprimé] / Abdelghani Bouabdallah, Auteur ; Abderrahmane Chaieb, Directeur de thèse . - constantine [Algérie] : Université Constantine 1, 2013 . - 62 f. ; 30 cm.
2 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
PhysiqueTags : Nano composite PMMA / ZnO les rayons X RX absorption optique émission optique- methode soi-gel spin coating X-rays X-ray optical absorption optical emission - so- gel method الامتصاص الضوئي الاتبعاث الفوتوضوئي طریقة صول-جال- RX الاشعة السینیة PMMA/ZNO رقائق نانو المركب Index. décimale : 530 Physique Résumé : This work to study the structural and optical ZnO nanocrystals
For the preparation of nano- zinc oxide was confused by Material:
LaCetate Zinc dihydrate , citric acid
For the preparation of nano ZnO by material : Zinc LaCetate dihydrate , citric acid
For the preparation of thin film nano composite material was :
, The nano ZnO powder , THF ( tetrahydrofuran ) , the léthanol PMMA After preparing thin layer were placed under a UV radiation Structural study of this course are made by thin film X-ray diffraction to determine the size of nanoscale crystals ZNO
Preliminary study using the optical absorption in the UV range of the following thin film showed absorption edge shift to higher energies and this is due to the small size of the nanocrystals ZNO The study by the program that the samples his boots intense emission in the , emission of visible and near UV makes this material prepared from the elements eligible for the use of applications in the field of optical and electrical .Diplôme : Magistère En ligne : ../theses/physique/BOU6464.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=9502 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité BOU/6464 BOU/6464 Thèse Bibliothèque principale Thèses Disponible Documents numériques
texte intégraleAdobe Acrobat PDFEtude structurale par diffraction X et optique linéaire de composites à base de nanocristaux semi-conducteurs (CdSe, ZnSe) dispérsés dans des matrices h?tes organiques (PMMA) et minérale (KBr, KCL) / Abderrahmane Chaieb
Titre : Etude structurale par diffraction X et optique linéaire de composites à base de nanocristaux semi-conducteurs (CdSe, ZnSe) dispérsés dans des matrices h?tes organiques (PMMA) et minérale (KBr, KCL) Type de document : texte imprimé Auteurs : Abderrahmane Chaieb ; Univ. de Constantine, Éditeur scientifique ; Miloid Sebais, Directeur de thèse Année de publication : 2009 Importance : 147 f. Note générale : 01 Disponible à la salle de recherche 01 Disponible au magazin de la B.U.C. 01 CD Langues : Français (fre) Catégories : Français - Anglais
PhysiqueTags : Propriétés structurales Nanocomposites CdSe/KBr ,CdSe/KCl, CdSe/PMMA , ZnSe/PMMA Propriétés optiques linéaires et non linéaires Index. décimale : 530 Physique En ligne : ../theses/physique/CHA5536.pdf Permalink : index.php?lvl=notice_display&id=3434 Etude structurale par diffraction X et optique linéaire de composites à base de nanocristaux semi-conducteurs (CdSe, ZnSe) dispérsés dans des matrices h?tes organiques (PMMA) et minérale (KBr, KCL) [texte imprimé] / Abderrahmane Chaieb ; Univ. de Constantine, Éditeur scientifique ; Miloid Sebais, Directeur de thèse . - 2009 . - 147 f.
01 Disponible à la salle de recherche 01 Disponible au magazin de la B.U.C. 01 CD
Langues : Français (fre)
Catégories : Français - Anglais
PhysiqueTags : Propriétés structurales Nanocomposites CdSe/KBr ,CdSe/KCl, CdSe/PMMA , ZnSe/PMMA Propriétés optiques linéaires et non linéaires Index. décimale : 530 Physique En ligne : ../theses/physique/CHA5536.pdf Permalink : index.php?lvl=notice_display&id=3434 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité CHA/5536 CHA/5536 Thèse Bibliothèque principale Thèses Disponible
Titre : La synthèse des nano particules de CuO avec la méthode de précipitation sol_ gel : en utilisant le précurseur CuCl2 et l'étude de leurs propriétés structurales et optiques Type de document : texte imprimé Auteurs : Rabie Bacha, Auteur ; Abderrahmane Chaieb, Directeur de thèse Editeur : constantine [Algérie] : Université Constantine 1 Année de publication : 2015 Importance : 91 f. Format : 30 cm. Note générale : 2 copies imprimées disponibles
Langues : Français (fre) Catégories : Français - Anglais
PhysiqueTags : Semi-conducteurs CuO composite nanocomposite matrice polymère procédé sol-gel masse effective « spin –coating » gap optique CuO/PMMA thin film powders (sol-gel) process optical properties structural analysis المساحيق الشرائح الرقيقة صول-جال أكسيد النحاس Index. décimale : 530 Physique Résumé : The object of this thesis is the synthesis and characterization of the copper oxide powders “CuO” and its composite thin film of (CuO/PMMA), by (sol-gel) process (wet-chemistry route), also the comparison between two methods of preparation using two different precursors.
The Work was divided into two parts:
The first part allowed to the preparation of the “CuO” powder, and its composite thin film of (CuO/PMMA), by the precursor (CuCl2, 2H2O), and the study of its structural, morphological, and optical properties, we also study in this part the annealing temperature effect on the size of CuO crystallites.
The second part was dedicated to prepare the CuO powder, and its composite thin film (CuO/PMMA), by precursor (Cu (CH3COO) 2, H2O), and DMF (CH3) 2 NC (OH), as solvent, and also the study of the structural, and optical properties.
Various analysis techniques have been used to characterize the CuO powders and its composite (CuO/PMMA) thin films, they are divided into two category:
- The structural analysis including the x-rays diffraction (XRD), the infrared spectroscopy (IR) and the electron scanning microscopy.
- Optical properties and band gap of CuO were studied by UV-Vis spectroscopy.
For the CuO powders prepared by the first precursor (CuCl2, 2H2O), and with different annealing temperatures, the study by x-rays diffraction (XRD) reveals single phase monoclinic structure of CuO, the average crystallite size increased with increasing of annealing temperature.
For the powder CuO to prepare with the second precursor (Cu (CH3COO) 2, H2O) the study by the x-rays diffraction(XRD) , reveals single phase monoclinic structure of CuO, the average crystallite size of the powder annealed to 450 C° is 16,76nm.
The study of the optical properties of the CuO/PMMA composite thin films by the two methods has shown a band gap is estimated to be 3, 90 eV.
Diplôme : Magistère En ligne : ../theses/physique/BAC6717.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=9906 La synthèse des nano particules de CuO avec la méthode de précipitation sol_ gel : en utilisant le précurseur CuCl2 et l'étude de leurs propriétés structurales et optiques [texte imprimé] / Rabie Bacha, Auteur ; Abderrahmane Chaieb, Directeur de thèse . - constantine [Algérie] : Université Constantine 1, 2015 . - 91 f. ; 30 cm.
2 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
PhysiqueTags : Semi-conducteurs CuO composite nanocomposite matrice polymère procédé sol-gel masse effective « spin –coating » gap optique CuO/PMMA thin film powders (sol-gel) process optical properties structural analysis المساحيق الشرائح الرقيقة صول-جال أكسيد النحاس Index. décimale : 530 Physique Résumé : The object of this thesis is the synthesis and characterization of the copper oxide powders “CuO” and its composite thin film of (CuO/PMMA), by (sol-gel) process (wet-chemistry route), also the comparison between two methods of preparation using two different precursors.
The Work was divided into two parts:
The first part allowed to the preparation of the “CuO” powder, and its composite thin film of (CuO/PMMA), by the precursor (CuCl2, 2H2O), and the study of its structural, morphological, and optical properties, we also study in this part the annealing temperature effect on the size of CuO crystallites.
The second part was dedicated to prepare the CuO powder, and its composite thin film (CuO/PMMA), by precursor (Cu (CH3COO) 2, H2O), and DMF (CH3) 2 NC (OH), as solvent, and also the study of the structural, and optical properties.
Various analysis techniques have been used to characterize the CuO powders and its composite (CuO/PMMA) thin films, they are divided into two category:
- The structural analysis including the x-rays diffraction (XRD), the infrared spectroscopy (IR) and the electron scanning microscopy.
- Optical properties and band gap of CuO were studied by UV-Vis spectroscopy.
For the CuO powders prepared by the first precursor (CuCl2, 2H2O), and with different annealing temperatures, the study by x-rays diffraction (XRD) reveals single phase monoclinic structure of CuO, the average crystallite size increased with increasing of annealing temperature.
For the powder CuO to prepare with the second precursor (Cu (CH3COO) 2, H2O) the study by the x-rays diffraction(XRD) , reveals single phase monoclinic structure of CuO, the average crystallite size of the powder annealed to 450 C° is 16,76nm.
The study of the optical properties of the CuO/PMMA composite thin films by the two methods has shown a band gap is estimated to be 3, 90 eV.
Diplôme : Magistère En ligne : ../theses/physique/BAC6717.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=9906 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité BAC/6717 BAC/6717 Thèse Bibliothèque principale Thèses Disponible
Titre : La synthèse des nano poudres de Cu O avec la méthode précipitation Sol-Gel en utilisant le précurseurCuSO4 et l’étude de leurs propriétés structurales et optiques Type de document : texte imprimé Auteurs : Sara Mehadjebi, Auteur ; Abderrahmane Chaieb, Directeur de thèse Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2015 Importance : 93 f. Format : 30 cm. Note générale : 2 copies imprimes disponibles . Langues : Français (fre) Catégories : Français - Anglais
PhysiqueTags : Sciences des Matériaux Semi Conducteurs
CuO sol gel DRX MEB infra rouge absorption méthodes de synthèses sol-gel process UV-Visible spectroscopy the infrared
spectroscopy(IR) methods of analysis أكسيد الحديد صول جول الشرائح الرقيقة طرق التحضيرIndex. décimale : 530 Physique Résumé : The Sol-Gel method is a very attractive technique for elaborating materials, since it is known to be
able to synthesize ,at low temperature ,both nanometric powders or materials with fine
microstructure .moreover, it ensures a high chemical purity and homogeneity and also controls ,in
an accurate manner ,the morphology of the synthesized materials .
In the present work we have fabricated and characterized pure copper oxide powders “CuO” and its
composite thin film (CuO/PMMA)by sol-gel process (wet-chemistry route) using two different
precursor (CuSO4+5H2 O) and (Cu(CH3 COO)2 ,H2 O) .
Various analysis techniques have been used to characterize the CuO powders and its composites
thin films, they are divided into two category:
The structural analysis including the X-rays diffraction (XRD),the infrared
spectroscopy(IR)and the electron scanning microscopy (MEB).
UV-Visible spectroscopy has been used for the determination of optical gap.
For the CuO prepared by the first precursor (CuSO4+5H2 O) and with different annealing
temperatures ,the study by X-rays diffraction (DRX) reveals single phase monoclinic structure of
CuO ,the average crystallite size change with annealing temperature .
For the CuO prepared by the second precursor (Cu(CH3 COO)2 ,H2 O) the study by X-rays
diffraction (XRD),reveals single phase monoclinic structure of CuO ,the average crystallite size of
the powder annealed to 450℃ is 16,76nm.
The study of optical properties of the CuO/PMMA composite thin films by the two methods has
shown a band gap is estimated to be 3.91eV.
Diplôme : Magistère En ligne : ../theses/physique/MEH6842.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=10117 La synthèse des nano poudres de Cu O avec la méthode précipitation Sol-Gel en utilisant le précurseurCuSO4 et l’étude de leurs propriétés structurales et optiques [texte imprimé] / Sara Mehadjebi, Auteur ; Abderrahmane Chaieb, Directeur de thèse . - جامعة الإخوة منتوري قسنطينة, 2015 . - 93 f. ; 30 cm.
2 copies imprimes disponibles .
Langues : Français (fre)
Catégories : Français - Anglais
PhysiqueTags : Sciences des Matériaux Semi Conducteurs
CuO sol gel DRX MEB infra rouge absorption méthodes de synthèses sol-gel process UV-Visible spectroscopy the infrared
spectroscopy(IR) methods of analysis أكسيد الحديد صول جول الشرائح الرقيقة طرق التحضيرIndex. décimale : 530 Physique Résumé : The Sol-Gel method is a very attractive technique for elaborating materials, since it is known to be
able to synthesize ,at low temperature ,both nanometric powders or materials with fine
microstructure .moreover, it ensures a high chemical purity and homogeneity and also controls ,in
an accurate manner ,the morphology of the synthesized materials .
In the present work we have fabricated and characterized pure copper oxide powders “CuO” and its
composite thin film (CuO/PMMA)by sol-gel process (wet-chemistry route) using two different
precursor (CuSO4+5H2 O) and (Cu(CH3 COO)2 ,H2 O) .
Various analysis techniques have been used to characterize the CuO powders and its composites
thin films, they are divided into two category:
The structural analysis including the X-rays diffraction (XRD),the infrared
spectroscopy(IR)and the electron scanning microscopy (MEB).
UV-Visible spectroscopy has been used for the determination of optical gap.
For the CuO prepared by the first precursor (CuSO4+5H2 O) and with different annealing
temperatures ,the study by X-rays diffraction (DRX) reveals single phase monoclinic structure of
CuO ,the average crystallite size change with annealing temperature .
For the CuO prepared by the second precursor (Cu(CH3 COO)2 ,H2 O) the study by X-rays
diffraction (XRD),reveals single phase monoclinic structure of CuO ,the average crystallite size of
the powder annealed to 450℃ is 16,76nm.
The study of optical properties of the CuO/PMMA composite thin films by the two methods has
shown a band gap is estimated to be 3.91eV.
Diplôme : Magistère En ligne : ../theses/physique/MEH6842.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=10117 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité MEH/6842 MEH/6842 Thèse Bibliothèque principale Thèses Disponible
Titre : Synthèse de nanoparticules de ZnS et études de leurs propriétés structurales et optiques Type de document : texte imprimé Auteurs : Abdelhamid Hadjadj, Auteur ; Abderrahmane Chaieb, Directeur de thèse Editeur : constantine [Algérie] : Université Constantine 1 Année de publication : 2014 Importance : 96 f. Format : 30 cm. Note générale : 2 copies imprimées disponibles
Langues : Français (fre) Catégories : Français - Anglais
PhysiqueTags : nano semi conducteur II-VI ZnS DRX effet de taille effet de surface confinement quantique semiconductor II-VI XRD size effect surface effect quantum confinement نانو؛نصف ناقل كبريت الزنك عامل السطح عامل الحصر الكوانتي بلورات إنعراج أشعة س Index. décimale : 530 Physique Résumé : This work focuses on the synthesis by the sol-gel method with nano precipitation ZnS powder, process carried out without any constraints related to the environment or the temperature or atmospheric pressure that is called process soft chemistry. In the preparation of the powder of ZnS was chosen the precursor sodium sulfide (Na2S) (99% pure Aldrich) as crystals as the sulfur source and the bi hydrated zinc acetate (Zn-C2H3O2-C2H3O2) 2H2O) (99% pure Aldrich), a powdered zinc source .These two components are mixed in suitable proportions. This method allowed us to recover a large amount of ZnS powder. The prepared powder was subsequently undergoes a heat treatment at different temperature to 450 ° C and 650 ° C, followed by the development of thin layers of the nanocomposite material ZnS / PMMA consisting of crystallites of pure nano ZnS dispersed in the poly methyl methacrylate. These materials were analyzed by X-ray diffraction for the structural characterization of the pure powder and annealed at a temperature 450 ° C and 650 ° C for one hour under the pressure of the atmosphere, and the optical characterization by absorption spectroscopy and emission (photoluminescence) explicitly for pure ZnS nano powders and thin layers of composite nano ZnS / PMMA.
The thin layers of ZnS / PMMA deposited on glass dimensions 1.5cm x 1.5cm substrates has been developed by the so-called spin-coating. Was used for the analysis of all our samples a diffractometer 'Bruker D8 Advance' 'equipped with a Cu Kα source. = 1.54148A °. XRD showed that:
-a- The structure of the pure ZnS powder is of the type zinc blende (cubic) with a lattice parameter a = 5.400A ° (sheet No. 010 792) and the average crystallite size estimated by Scherer's formula is: D = 2R = 4.08nm (quantum dots).
-b- The ZnS powder annealed at the temperature 450 ° C for one hour under the pressure of the atmosphere is an overlap of two phases, one phase of ZnS and ZnO phase. The latter is due to the effect of oxidation during annealing (oxygen is snuff in the air rate of 20%). The structure of nano crystallites changes to become hexagonal ZnS (JCPDS card No. 720163) with increase in the average size of the crystallites and becomes: D = 2R = 12.08nm. The structure of nano ZnO is hexagonal crystallites (JCPDS card No. 891397), their average size: D = 2R = 12.48nm.
-c- The oxidation is almost complete of the nano ZnS crystallites during annealing at 650 ° C for one hour under the pressure of the atmosphere, the structure of nano ZnO remains hexagonal crystallites (JCPDS card No. 891 397) with parameters a = 3.253A ° mesh; c = 5.213A °, therefore the crystallite size becomes greater: D = 2R = 31.26nm. We used a UV-visible spectrophotometer Shimadzu UV3101PC brand dual beam whose spectral range extending from 190 nm (UV) to 3200 nm (near IR) with a pitch of 0.5Nm
The study by optical absorption spectroscopy and photoluminescence in the UV-visible allowed to deduct the gap from the optical absorption spectrum of the nano-crystallites of pure ZnS, equal to Eg = 3.85 eV, the latter is subjected to a shift 0.3EV to major energy compared to the gap in the bulk state (3.55 eV) for the cubic structure of ZnS. This increase is due to the reduction in the size inducing quantum confinement. The size of the nano crystallites estimated pure ZnS by using the model of the effective mass, it is equal to D = 2R = 2x2.33nm = 4.66nm. This result is in good agreement with that found from X-ray diffraction spectra calculated by the formula Scherer. The radius of pure ZnS crystallites is of the same order of magnitude as the Bohr radius of the exciton (rB = 2.5Nm), which corresponds to an intermediate confinement. Emission spectra (PL) made using a Nd-YAG laser source with an excitation of 355 nm at the temperature of liquid nitrogen (77 ° K) can be observed three bands in the visible range attributed to the recombination of electrons of the sulfur levels in vacant locations with the holes in the valence band and also the surface defects and impurities.
In perspective, we can consider the use of nano ZnS crystallites in the field of nanotechnology as fluorescent nano-objects, sensors in the near infrared and also as a heart shell of another semiconductor because they present a wide gap and it is less sensitive to the effect of oxidation. In addition, the annealing mechanism nano ZnS powder under the pressure of the atmosphere may be used for the synthesis of nano ZnO crystallites.
Diplôme : Magistère En ligne : ../theses/physique/HAD6752.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=9863 Synthèse de nanoparticules de ZnS et études de leurs propriétés structurales et optiques [texte imprimé] / Abdelhamid Hadjadj, Auteur ; Abderrahmane Chaieb, Directeur de thèse . - constantine [Algérie] : Université Constantine 1, 2014 . - 96 f. ; 30 cm.
2 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
PhysiqueTags : nano semi conducteur II-VI ZnS DRX effet de taille effet de surface confinement quantique semiconductor II-VI XRD size effect surface effect quantum confinement نانو؛نصف ناقل كبريت الزنك عامل السطح عامل الحصر الكوانتي بلورات إنعراج أشعة س Index. décimale : 530 Physique Résumé : This work focuses on the synthesis by the sol-gel method with nano precipitation ZnS powder, process carried out without any constraints related to the environment or the temperature or atmospheric pressure that is called process soft chemistry. In the preparation of the powder of ZnS was chosen the precursor sodium sulfide (Na2S) (99% pure Aldrich) as crystals as the sulfur source and the bi hydrated zinc acetate (Zn-C2H3O2-C2H3O2) 2H2O) (99% pure Aldrich), a powdered zinc source .These two components are mixed in suitable proportions. This method allowed us to recover a large amount of ZnS powder. The prepared powder was subsequently undergoes a heat treatment at different temperature to 450 ° C and 650 ° C, followed by the development of thin layers of the nanocomposite material ZnS / PMMA consisting of crystallites of pure nano ZnS dispersed in the poly methyl methacrylate. These materials were analyzed by X-ray diffraction for the structural characterization of the pure powder and annealed at a temperature 450 ° C and 650 ° C for one hour under the pressure of the atmosphere, and the optical characterization by absorption spectroscopy and emission (photoluminescence) explicitly for pure ZnS nano powders and thin layers of composite nano ZnS / PMMA.
The thin layers of ZnS / PMMA deposited on glass dimensions 1.5cm x 1.5cm substrates has been developed by the so-called spin-coating. Was used for the analysis of all our samples a diffractometer 'Bruker D8 Advance' 'equipped with a Cu Kα source. = 1.54148A °. XRD showed that:
-a- The structure of the pure ZnS powder is of the type zinc blende (cubic) with a lattice parameter a = 5.400A ° (sheet No. 010 792) and the average crystallite size estimated by Scherer's formula is: D = 2R = 4.08nm (quantum dots).
-b- The ZnS powder annealed at the temperature 450 ° C for one hour under the pressure of the atmosphere is an overlap of two phases, one phase of ZnS and ZnO phase. The latter is due to the effect of oxidation during annealing (oxygen is snuff in the air rate of 20%). The structure of nano crystallites changes to become hexagonal ZnS (JCPDS card No. 720163) with increase in the average size of the crystallites and becomes: D = 2R = 12.08nm. The structure of nano ZnO is hexagonal crystallites (JCPDS card No. 891397), their average size: D = 2R = 12.48nm.
-c- The oxidation is almost complete of the nano ZnS crystallites during annealing at 650 ° C for one hour under the pressure of the atmosphere, the structure of nano ZnO remains hexagonal crystallites (JCPDS card No. 891 397) with parameters a = 3.253A ° mesh; c = 5.213A °, therefore the crystallite size becomes greater: D = 2R = 31.26nm. We used a UV-visible spectrophotometer Shimadzu UV3101PC brand dual beam whose spectral range extending from 190 nm (UV) to 3200 nm (near IR) with a pitch of 0.5Nm
The study by optical absorption spectroscopy and photoluminescence in the UV-visible allowed to deduct the gap from the optical absorption spectrum of the nano-crystallites of pure ZnS, equal to Eg = 3.85 eV, the latter is subjected to a shift 0.3EV to major energy compared to the gap in the bulk state (3.55 eV) for the cubic structure of ZnS. This increase is due to the reduction in the size inducing quantum confinement. The size of the nano crystallites estimated pure ZnS by using the model of the effective mass, it is equal to D = 2R = 2x2.33nm = 4.66nm. This result is in good agreement with that found from X-ray diffraction spectra calculated by the formula Scherer. The radius of pure ZnS crystallites is of the same order of magnitude as the Bohr radius of the exciton (rB = 2.5Nm), which corresponds to an intermediate confinement. Emission spectra (PL) made using a Nd-YAG laser source with an excitation of 355 nm at the temperature of liquid nitrogen (77 ° K) can be observed three bands in the visible range attributed to the recombination of electrons of the sulfur levels in vacant locations with the holes in the valence band and also the surface defects and impurities.
In perspective, we can consider the use of nano ZnS crystallites in the field of nanotechnology as fluorescent nano-objects, sensors in the near infrared and also as a heart shell of another semiconductor because they present a wide gap and it is less sensitive to the effect of oxidation. In addition, the annealing mechanism nano ZnS powder under the pressure of the atmosphere may be used for the synthesis of nano ZnO crystallites.
Diplôme : Magistère En ligne : ../theses/physique/HAD6752.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=9863 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité HAD/6752 HAD/6752 Thèse Bibliothèque principale Thèses Disponible
