| Titre : | The effect of solvents on the properties of thin films of (TiO2) deposited by sol gel (spin-coating) |
| Auteurs : | Roumaissa Messeddek, Auteur ; Loubna Messeddek, Auteur ; Hanane Saidi, 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, 2021 |
| Format : | 1 vol. (68 p.) / couv. ill. en coul / 30 cm |
| Langues: | Anglais |
| Mots-clés: | Solvents effect, TiO2 thin films , Sol Gel (sping-coating), structural properties, optical properties |
| Résumé : |
Transparent semiconducting thin films of titanium dioxide (TiO2) were deposited on glass substrates by the sol–gel method and spin-coating technique. using methanol, ethanol, isopropanol ,methoxyethanol and ethylene glycol as solvents ,titanium tetraisopropoxide as a precursor and acetyl acetone as a stabilizer agent .The effect of solvent medium on the structural, morphological , optical and electrical properties of TiO2 thin films were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-Vis spectroscopy (UV-Vis) ,Energy-dispersive X-ray spectroscopy ( EDS) and Four points method . The XRD patterns reveals that the films are crystalline with an anatase crystal structure and a preferred grain orientation in the (101) direction and the grains size change between (29.541 nm and 21.197 nm),The morphological properties were investigated by SEM, The surface morphology of the films was found to be strongly dependent on the solvent ,The UVVisible spectrum indicated that the films are highly transparent in the visible region and their transparency is slightly influenced by the film thickness, with an average value above 80 %, and a shift in optical band gap energy of the films from 3.75 to 3.54 eV for direct allowed ,and from 3.47 to 3.34 eV for indirect allowed, as a function of the solvents , has been observed , In addition, the electrical measures showed that the films have conductivity between (0.0073-66.66) Ω-1 .cm-1. |
| Sommaire : |
Table of contents Dedication..........................................i Acknowledgements.................................. ii Table of contents............................iii List of Figures............................vi List of Tables............................................................................ ix Introduction General........................................................................1 Chapter I:Thin Films deposition and characterization techniques І.1 Thin film technology....................................................................... 3 І.1.1 This film feature..............................................................................3 І.1.2 Formation stages of thin films...................................................................3 І.1.3 Thin film growth modes......................................... 4 І.2 Deposition techniques..........................................5 І.2.1Sol-gel technology....................................................5 І.2.2 Sol-gel method.................................... 6 І.2.2.1 Sol-gel chemistry tends to be particularly sensitive to the following parameter...9 І.2.2.1.1 Precursor properties ....................................................9 І.2.2.1.2 Reaction temperature.........................................................9 І.2.2.1.3 Gel time...........................................................................9 І.2.2.1.4 Solvent...........................................................................10 І.2.2.1.5 Properties and concentrations of catalyst.............................10 І.2.2.1.6 Ratio of water to metal alkoxide...............................................10 І.2.2.2 The relationship between gel time and reaction temperature......................11 І.2.2.3 Advantages of sol-gel method.........................11 І.3 Methods used to apply sol-gel on substra.................12iv І.3.1 Spin co.................. 12 І.3.1.1 Description of spin coating pro............................12 І.3.1.2 Thin films characteristics................... 15 І.3.1.3 Advantages disadvantages of Spin Coating.........................16 І.3.2 Drying...............16 І.3.3 Annealing..................... 16 І.4 Thin film characterization........................16 I.4.1 X-ray diffraction............................ 16 I.4.1.1 Determination of the crystallite size..................................18 I.4.1.2 Determination the dislocation density............................. 18 I.4.1.3 Determination of the deformation........................... 18 І.4.2 Spectroscopy(UV-VISIBLE)............................19 І.4.2.1 The thickness of the film.......................................21 І.4.2.2 Optical band gap (��)............. 22 І.4.2.3 Urbach energy (�u)....................................23 І.4.3 Scanning electron microscopy (SEM)............................... 24 І.4.4 Four-point probe method...................... 26 Chapter II :Generalities about titanium dioxide TiO2. II.1 Titanium dioxide........................................28 II.2 Properties of TiO2.................................. 28 II.2.1 Structural properties...............................28 II.2.1.1 Anatase..............................................28 II.2.1.2 Brookite..........................................................29 II.2.1.3 Rutile..........................................................................30 II.2.1.4 Stability of TiO2 phases............................................................... 32 II.2.2 Optical properties................................33 II.2.3 Electrical properties....................... 33 |
| Type de document : | Mémoire master |
Disponibilité (1)
| Cote | Support | Localisation | Statut |
|---|---|---|---|
| MPHY/559 | Mémoire master | bibliothèque sciences exactes | Consultable |
