Résultat de la recherche
9 résultat(s) recherche sur le tag 'AFM' 
Affiner la recherche Générer le flux rss de la recherche
Partager le résultat de cette recherche Interroger des sources externesEtude des propriétés physiques de couches minces TiO2 élaborées par différentes techniques / Faouzi Hanini
Titre : Etude des propriétés physiques de couches minces TiO2 élaborées par différentes techniques Type de document : texte imprimé Auteurs : Faouzi Hanini, Auteur ; A. Bouabellou, Directeur de thèse Editeur : constantine [Algérie] : Université Constantine 1 Année de publication : 2014 Importance : 115 f. Format : 30 cm. Note générale : 2 copies imprimées disponibles
Langues : Français (fre) Tags : Couche mince TiO2 Dopage Sol-Gel PLD DRX AFM SE.
Thin films Doping XRD ??????? ??????? ????? ??????? ??????? ????????? ??????? ???? ????? ??????Index. décimale : 530 Physique Résumé :
we have undertaken, the main objective optimization of parameters inherent to
both chemical (sol-gel) and physical (Pulsed Laser Deposition) used for the preparation of TiO2 thin films on different substrates. Structural, optical and electrical properties of these films were studied by mean of X-ray diffraction (XRD), atomic force microscopy (AFM), spectroscopic ellipsometry (SE), UV-Visible spectroscopy, and resistivity (conductivity) measurements.
Undoped and Cu-doped TiO2 (Cu:TiO2) thin films were deposited by sol-gel method on glass substrates. Structural, optical and electrical properties of undoped doped copper doped TiO2
films. XRD spectra show that the non-annealed sample is amorphous and crystallized anatase
phase from 400 °C. The obtained films are polycrystalline of anatase structure with (1 0 1) plan as preferential orientation. The surfaces of Cu-doped TiO2 films are smoother than undoped TiO2 films. The optical transmittance of simples is about 75 % in the visible region. The optical band gap undergoes a blue shift from 3.3 to 2.97 eV for undoped and 7at. % Cu doped TiO2 respectively. The values of the refractive index and the packing density increases, with increasing copper doping. The electrical characterization shows a maximum electrical conductivity of 1.29 (Ω cm)-1 obtained for the film doped with 7 at.% Cu.
Al-doped TiO2 (TiO2:Al) thin films were deposited at 450ºC onto glass substrates using pulsed laser deposition method. The used source was a Nd:YAG laser (λ = 335 nm, ν = 5 Hz, Φ = 2 J/cm2 and τ = 8 ns pulse duration). X-rays diffraction spectra showed that the obtained films are
polycrystalline of anatase structure with preferential orientation of (101) direction. AFM images, nanoparticles size and surface roughness mean square values showed that the surfaces of TiO2:Al films are smoother than that of undoped TiO2 films. A blue shift in the absorption edge of TiO2 with increasing Al concentration in the film is noteworthy as it leads to increase in the width of the optical transmission. The optical waveguiding performances of the TiO2:Al films were demonstrated by using the m-lines spectroscopy technique and the results were correlated to the structural properties. Spectroscopic ellipsometry was used to extract the optical constants of the films. The determined band gap of undoped and Al doped films varies from 3.43 to 3.61 eV,which is in accordance to Burstein-Moss shift.Diplôme : Doctorat en sciences En ligne : ../theses/physique/HAN6612.pdf Format de la ressource électronique : Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=9732 Etude des propriétés physiques de couches minces TiO2 élaborées par différentes techniques [texte imprimé] / Faouzi Hanini, Auteur ; A. Bouabellou, Directeur de thèse . - constantine (Route ain el bey, Algérie) : Université Constantine 1, 2014 . - 115 f. ; 30 cm.
2 copies imprimées disponibles
Langues : Français (fre)
Tags : Couche mince TiO2 Dopage Sol-Gel PLD DRX AFM SE.
Thin films Doping XRD ??????? ??????? ????? ??????? ??????? ????????? ??????? ???? ????? ??????Index. décimale : 530 Physique Résumé :
we have undertaken, the main objective optimization of parameters inherent to
both chemical (sol-gel) and physical (Pulsed Laser Deposition) used for the preparation of TiO2 thin films on different substrates. Structural, optical and electrical properties of these films were studied by mean of X-ray diffraction (XRD), atomic force microscopy (AFM), spectroscopic ellipsometry (SE), UV-Visible spectroscopy, and resistivity (conductivity) measurements.
Undoped and Cu-doped TiO2 (Cu:TiO2) thin films were deposited by sol-gel method on glass substrates. Structural, optical and electrical properties of undoped doped copper doped TiO2
films. XRD spectra show that the non-annealed sample is amorphous and crystallized anatase
phase from 400 °C. The obtained films are polycrystalline of anatase structure with (1 0 1) plan as preferential orientation. The surfaces of Cu-doped TiO2 films are smoother than undoped TiO2 films. The optical transmittance of simples is about 75 % in the visible region. The optical band gap undergoes a blue shift from 3.3 to 2.97 eV for undoped and 7at. % Cu doped TiO2 respectively. The values of the refractive index and the packing density increases, with increasing copper doping. The electrical characterization shows a maximum electrical conductivity of 1.29 (Ω cm)-1 obtained for the film doped with 7 at.% Cu.
Al-doped TiO2 (TiO2:Al) thin films were deposited at 450ºC onto glass substrates using pulsed laser deposition method. The used source was a Nd:YAG laser (λ = 335 nm, ν = 5 Hz, Φ = 2 J/cm2 and τ = 8 ns pulse duration). X-rays diffraction spectra showed that the obtained films are
polycrystalline of anatase structure with preferential orientation of (101) direction. AFM images, nanoparticles size and surface roughness mean square values showed that the surfaces of TiO2:Al films are smoother than that of undoped TiO2 films. A blue shift in the absorption edge of TiO2 with increasing Al concentration in the film is noteworthy as it leads to increase in the width of the optical transmission. The optical waveguiding performances of the TiO2:Al films were demonstrated by using the m-lines spectroscopy technique and the results were correlated to the structural properties. Spectroscopic ellipsometry was used to extract the optical constants of the films. The determined band gap of undoped and Al doped films varies from 3.43 to 3.61 eV,which is in accordance to Burstein-Moss shift.Diplôme : Doctorat en sciences En ligne : ../theses/physique/HAN6612.pdf Format de la ressource électronique : Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=9732 Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Etude structurale et optique de films minces ZnO élaborés par voie physique et/ou chimique Type de document : texte imprimé Auteurs : Adel Taabouche, Auteur ; A. Bouabellou, Directeur de thèse Editeur : Constantine : Université Mentouri Constantine Année de publication : 2015 Importance : 107 f. Format : 30 cm. Note générale : 2 copies imprimées disponibles
Langues : Français (fre) Tags : Sciences des matériaux Couche mince ZnO PLD Spray DRX AFM RBS M-lines UV-visible Effet Hall Thin films XRD Hall Effect ????? ????? ????????? ??????? ???? ??? ?????? ?????? ??????
??????? ??????? ??????? ??????? ?????? ??????? ??? ???Index. décimale : 530 Physique Résumé : In the present work, we have studied essentially the structural and optical properties of ZnO thin films elaborated using the physical technique s of the pulsed laser ablation (PLD) and the chemical method of the ultrasonic spray pyrolysis.
We have prepared undoped (ZnO) and cobalt-doped zinc oxide (CZO) thin films (Co: 3,5 at.%) by means of the PLD method. Synthesized films have been deposited on glass and silicon substrates heated at 450°C. The used source was a KrF eximer laser (248 nm, 25 ns, 2 J ⁄cm2). Different experimental techniques have been carried out to analyze the fabricated films: the X-ray diffraction (XRD), atomic force microscopy (AFM), Rutherford Backscattering spectrometry (RBS), UV-visible spectrophotometry, M-lines
spectroscopy and Hall effect.
While the ZnO films obtained by the ultrasonic spray technique have been deposited with different deposition times (10, 20, 30 min) on a glass substrate heated at 410 °C, and then they have characterized by XRD, AFM, UV-visible, M-lines and hall effect techniques.
The carried out study shows that all the prepared zinc oxide films have a hexagonal wurtzite-type structure and a preferentially oriented along the direction (002) confused with the c-axis perpendicular to the surface of the substrates. The grain sizes deducted from the XRD measurements vary between 24 and 40 nm. The optical coupling analysis realized by M-lines show that the ZnO films are monomode (for both TE and TM polarizations). However, the undoped ZnO film obtained by PLD is found to be two
guiding modes for TM. The films obtained have an optical transmission of 70 to 90% in the visible region of the spectrum and an optical band gap varying from 3.18 to 3.37 eV.
The electrical conductivity and the concentration of carriers, deduced from Hall effect measurements, are relatively low namely for the films prepared by spray pyrolysis technique.
Diplôme : Doctorat en sciences En ligne : ../theses/physique/TAA6719.pdf Format de la ressource électronique : Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=9904 Etude structurale et optique de films minces ZnO élaborés par voie physique et/ou chimique [texte imprimé] / Adel Taabouche, Auteur ; A. Bouabellou, Directeur de thèse . - Constantine : Université Mentouri Constantine, 2015 . - 107 f. ; 30 cm.
2 copies imprimées disponibles
Langues : Français (fre)
Tags : Sciences des matériaux Couche mince ZnO PLD Spray DRX AFM RBS M-lines UV-visible Effet Hall Thin films XRD Hall Effect ????? ????? ????????? ??????? ???? ??? ?????? ?????? ??????
??????? ??????? ??????? ??????? ?????? ??????? ??? ???Index. décimale : 530 Physique Résumé : In the present work, we have studied essentially the structural and optical properties of ZnO thin films elaborated using the physical technique s of the pulsed laser ablation (PLD) and the chemical method of the ultrasonic spray pyrolysis.
We have prepared undoped (ZnO) and cobalt-doped zinc oxide (CZO) thin films (Co: 3,5 at.%) by means of the PLD method. Synthesized films have been deposited on glass and silicon substrates heated at 450°C. The used source was a KrF eximer laser (248 nm, 25 ns, 2 J ⁄cm2). Different experimental techniques have been carried out to analyze the fabricated films: the X-ray diffraction (XRD), atomic force microscopy (AFM), Rutherford Backscattering spectrometry (RBS), UV-visible spectrophotometry, M-lines
spectroscopy and Hall effect.
While the ZnO films obtained by the ultrasonic spray technique have been deposited with different deposition times (10, 20, 30 min) on a glass substrate heated at 410 °C, and then they have characterized by XRD, AFM, UV-visible, M-lines and hall effect techniques.
The carried out study shows that all the prepared zinc oxide films have a hexagonal wurtzite-type structure and a preferentially oriented along the direction (002) confused with the c-axis perpendicular to the surface of the substrates. The grain sizes deducted from the XRD measurements vary between 24 and 40 nm. The optical coupling analysis realized by M-lines show that the ZnO films are monomode (for both TE and TM polarizations). However, the undoped ZnO film obtained by PLD is found to be two
guiding modes for TM. The films obtained have an optical transmission of 70 to 90% in the visible region of the spectrum and an optical band gap varying from 3.18 to 3.37 eV.
The electrical conductivity and the concentration of carriers, deduced from Hall effect measurements, are relatively low namely for the films prepared by spray pyrolysis technique.
Diplôme : Doctorat en sciences En ligne : ../theses/physique/TAA6719.pdf Format de la ressource électronique : Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=9904 Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Contribution à l’étude de couches minces de siliciures formés sur le silicium : (Ni,Co)/Si Type de document : texte imprimé Auteurs : Charafeddine Sedrati, Auteur ; A. Bouabellou, Directeur de thèse Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2015 Importance : 147 f. Format : 30 cm. Note générale : 2 copies imprimées disponibles
Langues : Français (fre) Tags : Thin films cobalt nickel silicide sheet resistance RBS GIXRD AFM RAMAN.
Couches minces siliciures résistance carrée ????? ????? ?????? ???????? ??????????? ????????? ??????????Index. décimale : 530 Physique Résumé : This work focuses on the study of the formation of silicides by the solid state reaction in the Co/Ni/Si(100) and Ni/Co/Si(100) systems. The samples are obtained by a vacuum thermal evaporation of Co-Ni and Ni-Co bilayers on Si(100) substrates followed by a thermal annealing in air in the temperature range of 300 - 800 °C. The Grazing incidence X rays diffraction (GIXRD), the Rutherford backscattering spectroscopy (RBS), the atomic force microscopy (AFM), the Raman spectroscopy and the measurement of the electric resistivity by using the our-point method are the experimental techniques employed for samples characterization.
The analysis the Co/Ni/Si(100) system annealed at 300°C shows that the nickel reacts
initially with the Si substrate to form the Ni2Si silicide, and the cobalt diffuses to form
the (CoxNi1 -x)2Si phase. Then, the Ni2Si phase transforms to the NiSi monosilicide
which remains stable up to a temperature of 600°C. In addition, Co begins to react with the silicon to form the various phases of cobalt silicide. Beyond the temperature of 500°C, the ternary (CoxNi1 -x)Si2 phase appears. The formation of this ternary phase is confirmed by the shift of the peaks in the Raman spectrum. RBS technique shows that the ternary phase (CoxNi1 -x)Si2 is formed with different concentrations of Ni and Co elements with the thickness varying between 30 and 50 nm. Electrical measurements show that the obtained ternary silicide is more considered than the binary silicides because of its low resistivity and its high thermal stability.
For the Ni/Co/Si(100) system, the analysis allows to observe the formation of different silicides at different temperatures. Indeed, it is clearly confirmed the coexistence of both CoSi and Co2Si phases at 300 °C, the formation of Ni2Si rich nickel silicide at 400 °C followed by the formation of the NiSi, this latter keeps its thermal stability up to 700 °C, and finally the formation of NiSi2 at 800 ° C. The apparition of the ternary (CoxNi1 -x)Si phase takes place at 500°C.
Diplôme : Doctorat en sciences En ligne : ../theses/physique/SED6806.pdf Format de la ressource électronique : Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=10059 Contribution à l’étude de couches minces de siliciures formés sur le silicium : (Ni,Co)/Si [texte imprimé] / Charafeddine Sedrati, Auteur ; A. Bouabellou, Directeur de thèse . - [S.l.] : جامعة الإخوة منتوري قسنطينة, 2015 . - 147 f. ; 30 cm.
2 copies imprimées disponibles
Langues : Français (fre)
Tags : Thin films cobalt nickel silicide sheet resistance RBS GIXRD AFM RAMAN.
Couches minces siliciures résistance carrée ????? ????? ?????? ???????? ??????????? ????????? ??????????Index. décimale : 530 Physique Résumé : This work focuses on the study of the formation of silicides by the solid state reaction in the Co/Ni/Si(100) and Ni/Co/Si(100) systems. The samples are obtained by a vacuum thermal evaporation of Co-Ni and Ni-Co bilayers on Si(100) substrates followed by a thermal annealing in air in the temperature range of 300 - 800 °C. The Grazing incidence X rays diffraction (GIXRD), the Rutherford backscattering spectroscopy (RBS), the atomic force microscopy (AFM), the Raman spectroscopy and the measurement of the electric resistivity by using the our-point method are the experimental techniques employed for samples characterization.
The analysis the Co/Ni/Si(100) system annealed at 300°C shows that the nickel reacts
initially with the Si substrate to form the Ni2Si silicide, and the cobalt diffuses to form
the (CoxNi1 -x)2Si phase. Then, the Ni2Si phase transforms to the NiSi monosilicide
which remains stable up to a temperature of 600°C. In addition, Co begins to react with the silicon to form the various phases of cobalt silicide. Beyond the temperature of 500°C, the ternary (CoxNi1 -x)Si2 phase appears. The formation of this ternary phase is confirmed by the shift of the peaks in the Raman spectrum. RBS technique shows that the ternary phase (CoxNi1 -x)Si2 is formed with different concentrations of Ni and Co elements with the thickness varying between 30 and 50 nm. Electrical measurements show that the obtained ternary silicide is more considered than the binary silicides because of its low resistivity and its high thermal stability.
For the Ni/Co/Si(100) system, the analysis allows to observe the formation of different silicides at different temperatures. Indeed, it is clearly confirmed the coexistence of both CoSi and Co2Si phases at 300 °C, the formation of Ni2Si rich nickel silicide at 400 °C followed by the formation of the NiSi, this latter keeps its thermal stability up to 700 °C, and finally the formation of NiSi2 at 800 ° C. The apparition of the ternary (CoxNi1 -x)Si phase takes place at 500°C.
Diplôme : Doctorat en sciences En ligne : ../theses/physique/SED6806.pdf Format de la ressource électronique : Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=10059 Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
Titre : Etude de l’effet de la composition d’une couche mince et de ses conditions d’élaboration par plasma froid à partir de vapeurs organosiliciées sur les propriétés de surface d’un film polymérique Type de document : texte imprimé Auteurs : Abdelouahab Nouicer Ilyès dit, Auteur ; Salah Sahli, Directeur de thèse Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2017 Importance : 159 f. Format : 30 cm. Note générale : 2 copies imprimées disponibles
Langues : Français (fre) Tags : HMDSO Polyimide traitement de surface mouillabilité super-hydrophobie nanopoudre PECVD RCER FTIR MEB AFM surface treatment wettability super-hydrophobic nanopowder SEM ????????? ?????? ????? ????? ???????? ??????????? Index. décimale : 621 Electronique Résumé : Plasma polymerization of hexamethyldisiloxane (PPHMDSO) was used to deposit SiOxCyHz thin films on silicon and polyimide substrates, using low-frequency plasma and microwave plasma discharge at low pressure. The effects of plasma chamber pressure, oxygen rate in Ar/O2 mixture, treatment time and post-treatment on the films characteristics were studied.
The thickness, surface properties and chemical structure of the deposited thin films were analyzed using profilo-meter measurements, scanning electron microscopy (SEM), static contact angle and infrared spectroscopy (FTIR and FTIR-ATR). At low frequencies and for certain deposition parameters, nano-powders of different concentrations and sizes were
observed on the deposited thin films surface. The FTIR analysis revealed that the chemical formula of the deposited layers is close to SiOxCyHz one, with more organic character when chamber pressure and/or deposition time were increased. Water contact angle measurements show that the increase in the deposition pressure and deposition time leads to the growth on
the polyimide and silicon substrates of thin layers with super-hydrophobic surface due to the increase in the concentration of the nano-powders on the treated surfaces. Plasmas created in HMDSO vapours using a microwave frequency plasma in ECR reactor leads to the deposition of similar PPHMDSO thin layer on polyimide and silicon surfaces. A post-treatment of these
coating layers using a microwave plasma created in Ar/O2 mixtures shows that the increase of oxygen rate in this mixture and the increase in the post-treatment time induces a significant decrease of the contact angle because of a decrease in the layers roughness (revealed by AFM characterization) and mainly, because of a more surface oxidation of the thin layers (revealed by FTIR analyzes)
Diplôme : Doctorat en sciences En ligne : ../theses/electronique/NOU7147.pdf Format de la ressource électronique : Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=10456 Etude de l’effet de la composition d’une couche mince et de ses conditions d’élaboration par plasma froid à partir de vapeurs organosiliciées sur les propriétés de surface d’un film polymérique [texte imprimé] / Abdelouahab Nouicer Ilyès dit, Auteur ; Salah Sahli, Directeur de thèse . - [S.l.] : جامعة الإخوة منتوري قسنطينة, 2017 . - 159 f. ; 30 cm.
2 copies imprimées disponibles
Langues : Français (fre)
Tags : HMDSO Polyimide traitement de surface mouillabilité super-hydrophobie nanopoudre PECVD RCER FTIR MEB AFM surface treatment wettability super-hydrophobic nanopowder SEM ????????? ?????? ????? ????? ???????? ??????????? Index. décimale : 621 Electronique Résumé : Plasma polymerization of hexamethyldisiloxane (PPHMDSO) was used to deposit SiOxCyHz thin films on silicon and polyimide substrates, using low-frequency plasma and microwave plasma discharge at low pressure. The effects of plasma chamber pressure, oxygen rate in Ar/O2 mixture, treatment time and post-treatment on the films characteristics were studied.
The thickness, surface properties and chemical structure of the deposited thin films were analyzed using profilo-meter measurements, scanning electron microscopy (SEM), static contact angle and infrared spectroscopy (FTIR and FTIR-ATR). At low frequencies and for certain deposition parameters, nano-powders of different concentrations and sizes were
observed on the deposited thin films surface. The FTIR analysis revealed that the chemical formula of the deposited layers is close to SiOxCyHz one, with more organic character when chamber pressure and/or deposition time were increased. Water contact angle measurements show that the increase in the deposition pressure and deposition time leads to the growth on
the polyimide and silicon substrates of thin layers with super-hydrophobic surface due to the increase in the concentration of the nano-powders on the treated surfaces. Plasmas created in HMDSO vapours using a microwave frequency plasma in ECR reactor leads to the deposition of similar PPHMDSO thin layer on polyimide and silicon surfaces. A post-treatment of these
coating layers using a microwave plasma created in Ar/O2 mixtures shows that the increase of oxygen rate in this mixture and the increase in the post-treatment time induces a significant decrease of the contact angle because of a decrease in the layers roughness (revealed by AFM characterization) and mainly, because of a more surface oxidation of the thin layers (revealed by FTIR analyzes)
Diplôme : Doctorat en sciences En ligne : ../theses/electronique/NOU7147.pdf Format de la ressource électronique : Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=10456 Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
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) Tags : 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)
Tags : 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
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire
PermalinkPermalink
Permalink
Permalink
