| Titre : | Development and characterization of pure and doped ZnO nanopowder with Ga and Bi via the sol-gel method. |
| Auteurs : | Saada Khaoula, Auteur ; Louiza Arab , Directeur de thèse |
| Type de document : | Monographie imprimée |
| Editeur : | Biskra [Algérie] : Faculté des Sciences Exactes et des Sciences de la Nature et de la Vie, Université Mohamed Khider, 2023 |
| Format : | 1vol(65) |
| Langues: | Français |
| Mots-clés: | zinc oxide, Bismuth, Gallium, nanopowder, sol-gel, XRD, UV–Vis, FTIR |
| Résumé : |
In this work, pure ZnO and Bi-doped ZnO and Ga-doped ZnO and (Ga+Bi)-doped ZnO nanopowders with concentrations 3% , have been successfully synthesized with a soft chemistry method: the sol-gel. This method produces samples with high purity, homogeneity, and a structure of easy control. The powders have been characterized using the following techniques: X-ray diffraction (XRD), UV–visible spectroscopy (UV–Vis), and Fourier transform infrared (FTIR) spectroscopy.
The XRD results confirm that all the samples exhibit a polycrystalline hexagonal wurtzite structure of the ZnO. The results of UV analysis showed a increase in the values of the band gap energy (Eg). In addition, Fourier transforms infrared (FTIR) spectroscopy showed the presence of a zinc oxide-specific bond in the samples. |
| Sommaire : |
DEDICATION ............. I
ACKNOWLEDGEMENTS ............. II List Of Figures .............. VI List Of Tables ............... VIII General Introduction.......... 1 References ................... 3 Chapter IBibliographic studies ................. 4 I.1. Zinc Oxide «ZnO» .......................... 5 I.2.Why choose ZnO specifically ? .............. 5 I.3. Properties of zinc oxide .................. 6 I.3.1. Physical Properties ..................... 6 I.3.1.1. Structural properties of ZnO .......... 7 I.3.1.2. Electrical properties ................. 10 I.3.1.3. Optical properties .................... 11 I.3.1.4. Electronic band structure ............. 11 I.3.1.5. Mechanical properties ................. 12 I.3.2. Chemical Properties ..................... 12 I.3.3. Catalytic properties .................... 13 I.4. ZnO doping ................................ 13 I.4.1. Doping with Bi .......................... 14 I.4.2. Doping with Ga .......................... 14 I.5. Nanomaterials ............................. 15 I.5.1. Nanoparticles ........................... 15 I.5.2. Classification of nanomaterials ......... 16 I.6. Applications of zinc oxide ................ 17 I.6.1. ZnO powder applications ................. 18 I.6.2. ZnO applications in thin film ........... 18 I.6.2.1. Solar Cells ........................... 18 I.6.2.2. Light emitting diodes ................. 19 I.6.2.3. Gas sensor ............................ 19 I.6.2.4.Varistors .............................. 20 IV I.6.2.5. Medical ............................... 20 References ..................................... 21 Chapter II methods and materials ............... 24 II.1.Methods of synthesis of nanomaterials ..... 25 II.2. The sol-gel method ....................... 25 II.2.1. Ways of the Sol-Gel process ............ 27 II.2.1.1. Inorganic or colloidal route ......... 27 II.2.1.2. Metallo-organic or polymeric pathway ...... 27 II.2.2. Predominant chemical reactions............... 28 II.2.2.1. Hydrolysis reaction ....................... 28 II.2.2.2. Condensation reaction ..................... 28 II.2.3. The sol-gel transition ...................... 29 II.2.4. Study of gelification time .................. 30 II.2.5. Drying ...................................... 30 II.2.5.1. Xerogel ................................... 30 II.2.5.2. Aerogel ................................... 31 II.2.6. Parameters influencing the kinetics of reactions ........ 31 II.2.7. Advantages and disadvantages of sol-gel ................. 32 II.2.8. Applications of Sol Gel method .......................... 32 II.3. Preparation of pure ZnO powders doped with gallium «Ga» and «Bi» ............ 33 II.3.1. Preparation Steps ............... 35 II.3.1.1. Cleaning glass ................ 35 II.3.1.2. Pure ZnO nano-powders ......... 35 II.3.2.3. Bi-doped ZnO nano-powders .......... 36 II.3.2.4. Ga+Bi co-doped ZnOnano-powders ...... 36 II.3.3. Calcination treatment ................. 36 II.4. ZnO powder characterization techniques .......... 39 II.4.1. X-ray diffraction ........... 39 II.4.1.1. Grain Size ................ 40 II.4.1.2. The interreticular distances and the cell parameters .......... 40 II.4.1.3. The lattice strain ............. 41 II.4.1.4. The dislocation density ........ 41 II.4.2. UV-Visible spectrophotometry ..... 41 II.4.2.1. Absorption coefficient ......... 42 II.4.2.2. Optical Gap Eg ................. 43 V II.4.2.3. Sample preparation ............. 43 II.4.3. Fourier Transform Infrared Spectroscopy (FTIR) ..... 44 II.4.3.1. Sample preparation .......... 45 References ............. 47 Chapter III Results and discussions ............ 50 III.1 Results and discussions .................. 51 III.1.1. structural study ...................... 51 III.1.1.1. Crystallite size, Lattice strain and Dislocation density variation .................. 53 III.1.1.2. Lattice parameters .................. 55 III.1.2. Optical study ......................... 56 III.1.3. Chemical study ........................ 59 References ....................... 61 General conclusion ............... 63 Abstract ......................... 65 |
Disponibilité (1)
| Cote | Support | Localisation | Statut |
|---|---|---|---|
| MPHY/631 | Mémoire master | bibliothèque sciences exactes | Consultable |
