| Titre : | Synthesis and Characterization of Mg Doped CuO Thin films. |
| Auteurs : | Linda Gherbia, Auteur ; Siham Gherbia, Auteur ; Kenza Almi , 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, 2020 |
| Format : | 1 vol. (65 p.) / couv. ill. en coul / 30cm |
| Langues: | Anglais |
| Mots-clés: | Thin films,Magnesium dopant,CuO,Optical properties. |
| Résumé : |
In this study we deposited non doped and Mg doped CuO thin films with different doping ratios (0%-1%-3%-5%-7%-9%) onto glass substrates by sol gel spin coating method with setting other parameters such as the concentration of the solution, rotational speed, the annealing time and annealing temperature, The prepared films were obtained by dissolving copper acetate in a mixture of ethanol and magnesium acetate as doped source. Our main goal is the study of the possibility to enhance the optical properties of CuO thin films. To achieve our goal, Mg doped thin films were analyzed by the UV-Visible spectroscopy. The experimental results show that: all the transmittance values of the films are between 25% and 75%, 1% and 3% films record the less value of transmittance in the visible range, while 9% records the highest one (75%). As for the absorption spectra, 1% and 3% absorbs more than 50 % of the incident photons; it was found that the optical gap decreases with the increasing doping percentage, its value ranges between (3.372 ev to 3.879 ev).Whereas, the Reflection of the films is between 0.15 and 0.25, and the refractive index varies between (2.2 to 2.6). |
| Sommaire : |
Acknowledgements Table of contents ……………………………………………………………………..i List of figure …………………………………………………………………………..v List of Tables ………………………………………………………………………..vii General Introduction ……………………………………………………………..........1 References of General Introduction …………………………………………………..3 Chapter I: Bibliographic Study on TCO Thin Films and Deposit Techniques. 1. Introduction: ……………………………………………………………………….4 2. Generalities about thin films: ……………………………………………….. …….4 2.1. Definition of thin films: ………………………………………………………4 2.2. Thin films growth mechanisms: ………………………………………….......4 3. The technique of depositing thin films: …………………………………….............4 4. Sol-Gel method: ……………………………………………………………............5 4.1. Definition: …………………………………………………………………...5 4.2. Principle: ……………………………………………………………………..5 4.3. Chemical reactions in the Sol-Gel process: …………………………………..7 4.4. Sol-Gel transition: ……………………………………………………………7 4.5. Advantages and Disadvantages of Sol-Gel method: …………………………8 4.5.1. The advantages: …………………………………………………….......8 4.5.2. The disadvantage………………………………………………………..8 4.6. Techniques of deposition: ……………………………………………………9 4.6.1. Spin-Coating technique: ………………………………………………..9 4.6.2. Dip-Coating technique: ………………………………………………...9 4.6.3. Spray pyrolysis technique: …………………………………………...10 ii 4.6.4. Ultrasonic spray technique: …………………………………………...11 4.6.5. Spray pneumatic technique: ………………………………………….11 5. Transparent Conducting Oxide (TCO): ……………………………………. …….12 5.1. Definition of TCOs: ………………………………………………………...12 5.2. TCOs Materials: …………………………………………………………….12 5.3. Physical properties of TCOs: …………………………………………….....13 5.3.1. Electrical conductivity: ……………………………………………….13 5.3.2. Optical properties……………………………………………………..14 5.4. Applications of TCOs: ……………………………………………………...15 6. Generalities about copper oxide: ………………………………………….............16 6.1. The choice of copper oxide: ………………………………………………...16 6.2. Copper oxides Cu2O and CuO: ……………………………………………..16 6.2.1. Cu2O oxide (cuprite): …………………………………………………16 6.2.2. Structural properties: ………………………………………………….16 6.2.3. CuO oxide (tenorite): …………………………………………………18 6.2.3.1. Physical and chemical properties of cupric oxide (CuO): ………19 6.2.3.2. Crystal structure of cupric oxide thin films: …………………….19 6.2.3.3. Structural properties: ……………………………………………21 6.2.3.4. Optical properties: ………………………………………………21 6.2.3.5. Electrical properties: …………………………………………….22 6.2.3.6. Electronic transmission properties CuO: ………………………..23 6.3. Application of copper oxide: ……………………………………………......24 7. Previous work on copper oxide CuO: …………………………………………….24 References of Chapter I: ……………………………………………………………..26 Chapter II: Elaboration and Characterization of CuO Thin Films. 1. Introduction: ………………………………………………………………………29 2. Chemical components used in the preparation of solutions: ……………………...29 2.1. Precursor: ………………………………………………………………… .29 iii 2.2. The source of dopants: ……………………………………………………..30 2.3. The solvent: …………………………………………………………………30 2.4. Catalyst: ……………………………………………………………………..31 3. Experimental procedure: ………………………………………………….. ……..32 3.1. Preparation of Substrates: …………………………………………………...32 3.1.1. Choice of substrates: …………………………………………………32 3.1.2. Substrates cut: ………………………………………………………..32 3.1.3. Substrates Cleaning Process: ………………………………………….33 3.2. Preparation of solutions: …………………………………………………….34 3.3. Deposition of Thin Films: ………………………………………… ……….35 3.3.1. Spin coating method: ………………………………………………...35 3.3.2. Heat treatment: ……………………………………………………….36 3.3.3. Drying thin films: ……………………………………………………36 3.3.4. Annealing Thin Films: ……………………………………………….37 3.3.5. Characterization Techniques of Thin Films: ………………………...40 3.4. Structural characterization: ………………………………………………….40 3.4.1. X-Ray Diffraction (XRD): ……………………………………………40 3.4.1.1. Principle of analysis: ……………………………………………40 3.4.1.2. The apparatus used in this study: ……………………………….42 3.4.1.3. Determination of the inter-reticular distances And the cell parameters: ………………………….……………………...43 3.4.1.4. Determination of the Grain Size: ………………………………..43 3.4.1.5. Determination of constraints: …………………………………...44 3.4.1.6. Determination of Dislocations’ density: ………………………...45 3.5. Optical characterization: ………………………………………….................45 3.5.1. Ultraviolet-visible spectroscopy (UV- VIS): ………………………...45 3.5.2. The Thickness of the Film: ……………………………………………47 3.5.2.1. The Approximate Gravimetric Method: ………………………47 3.5.2.2. Measurement of thickness by interference fringe method: ……..47 iv 3.5.3. Determination of the absorption coefficient: ………………………….48 3.5.4. Determination of the optical gap: ……………………………………..49 3.5.5. Determination of The disorder (the energy of Urbach): ………………50 3.5.6. Determination of the refractive index: ………………………………..51 References of Chapter II: …………………………………………………................52 Chapter III: Results and Discussion. 1 Introduction: …………………………………………………………………55 2 Optical Properties of Mg Doped CuO Thin Films: ………………………….55 2.1. Transmittance spectra: ………………………………………………………55 2.2. Absorbance spectra: ………………………………………………………...56 2.3. The absorption coefficient: …………………………………….....................56 2.4. The optical Gap (Eg): ……………………………………………………….57 2.5. The Disorder (Urbach energy): ……………………………………………..59 2.6. The reflection: ………………………………………………………………61 2.7. The extinction coefficient K: ………………………………………………..62 2.8. The refractive index n: ……………………………………………………...63 References of Chapter III: …………………………………………………………...64 General Conclusion …………………………………………………………….. …..65 |
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