| Titre : | Elaboration and characterization of thin layers of zinc oxide (ZnO) deposited by ultrasonic spray for photovoltaic and optoelectronic applications |
| Auteurs : | Youcef Benkheta, Auteur ; Abdallah Attaf, Directeur de thèse ; Hanane Saidi, Directeur de thèse |
| Type de document : | Thése doctorat |
| Editeur : | Biskra [Algérie] : Faculté des Sciences Exactes et des Sciences de la Nature et de la Vie, Université Mohamed Khider, 2019 |
| Format : | 1 vol. (90 p.) / 30 cm |
| Langues: | Anglais |
| Mots-clés: | Zinc oxide (ZnO) - ultrasonic spray - solution concentration - substrat temperature – tin doping concentration – annealing temperature. |
| Résumé : |
In this work we have developed thin layers of Zinc oxide (ZnO) by ultrasonic spray technique (SPU). We have modified some parameters such as the solution flow rate, the concentration of the solution, the substrate temperature (Ts), the tin concentration and the annealing temperature. The result obtained demonstrated that our ZnO films were crystallized according to the wurtzite hexagonal structure. For undoped layers deposited in deferent flow values from 50 ml / h up to 150 ml / h. the grain size decreased from 36.79 nm to 20.11 nm. The transmittance is about 80% in the visible range. The resistivity varies from 1.59 × 〖10〗 ^ (- 2) Ω.cm up to 43Ω.cm. for thin layers elaborated in deferent concentration value. The maximum transmittance value is 88% (the film thickness is 580 nm). The resistivity varied from 1.1 x 10-1Ω.cm up to 8.1 x 10-1Ω.cm. For thin layers made in deferent substrate temperature varied from 250 ° C to 500 ° C. The grain size was found to increase from 27.56 nm to 71.09 nm. The optical transparency is about 85%. The resistivity was decreased from 20 Ω.cm to 8.2 x 10-1Ω.cm. For thin layers deposited from changing the tin concentration, the grain size ranged from 12.85 nm to 39.18 nm. The transmittance is about 80%. The varied electrical resistivity from 43 Ω.cm to 1.2 x 10-2Ω.cm. The study of the annealing temperature has been indicated that the crystalline state of our thin layers will improve with increasing annealing temperature. The grain size varied between 12.9 nm and 46.94 nm. The varied electrical resistivity from 2.75 Ω.cm to 15 Ω.cm. |
| Sommaire : |
Acknowledgements Contents General introduction .................................................................... 1 Chapter I Review of thin films, Zinc Oxide Properties and their Applications I.1. Introduction .......................................................................................................... 4 I.2 Thin films growth process .................................................................................................. 4 I.3 Growth modes ........................................................................................................ 5 I.4 Zinc oxide ............................................................................................................... 7 I.4.1 Structural properties ....................................................................................................... 7 I.4.2 native defects in ZnO ...................................................................................................... 9 I.4.3 Optical properties ........................................................................................................ 10 I.4.4 Electronic properties ......................................................................................... 10 I.4.5 Electrical properties ..................................................................................................... 12 I.4.6 Applications of Zinc Oxide ................................................................................ 13 Chapter II Spray pyrolysis and characterization methods II.1. Introduction ................................................................................................................... 17 II.2. Thin films depositions techniques ....................................................................... 17 II.3. Spray pyrolysis technique (SP) ..................................................................................... 17 II.3.1 spray pyrolysis equipment ........................................................................................... 17 II.3.2 spray pyrolysis process .............................................................................................. 19 II.3.3 Spray pyrolysis parameters ......................................................................................... 22 II.4.Charactirization methods .................................................................................... 22 II.5. Cleaning substrate…………………...…………………………………………………………29 Chapter III The solution flow rate and concentration influence on ZnO thin films properties. III.1 Introduction .................................................................................................................... 30 III.2 Solution flow rate effect .............................................................................................. 30 III.2.1 Experimental details ................................................................................................... 30 III.2.2 The used technique .................................................................................................... 30 III.2.3 Structural properties ................................................................................................... 31 III.2.4 Morphological properties ............................................................................................ 34 III.2.5 Deposition rate ........................................................................................................... 36 III.2.6 Optical properties ....................................................................................................... 36 III.2.7 Electrical properties ................................................................................................... 38 III.3.Solution concentration effect ................................................................................ 93 III.3.1 Experimental details ............................................................................................... 93 III.3.2 Structural properties ................................................................................................... 93 III.3.3 Optical properties ...................................................................................................... 49 III.3.4 Electrical properties ................................................................................................... 44 III.4 Conclusion..................................................................................................................... 46 Chapter IV Influence of substrate temperature IV.1 introduction ................................................................................................................. 48 IV.2 experimental details ................................................................................................... 48 IV.3. Sprayed solution droplets ............................................................................................ 43 IV.4. Structural properties .................................................................................................... 43 IV.4.1 XRD analysis ............................................................................................................. 43 IV.4.2 Crystallite size ........................................................................................................... 50 IV.4.9 Strain and lattice parameter ...................................................................................... 52 IV.5. Deposition rate ............................................................................................................. 54 IV.6 Optical properties ......................................................................................................... 55 IV.6.1 Optical transmittance… …………………….………….………….…………………..…...55 IV.6.2 Optical band gap Eg ................................................................................................. 55 IV.7 Electrical conductivity .................................................................................................... 57 IV.8 Photoluminescence spectra ......................................................................................... 53 IV.9. Conclusion ................................................................................................................... 60 Chapter V: Tin doping concentration and Annealing temperature effect on ZnO thin films properties. V.1 Introduction .................................................................................................................... 62 V.2 the effect of tin doping concentration ........................................................................ 62 V.2.1 experimental details .................................................................................................... 62 V.2.2 structural properties .................................................................................................... 62 V.2.2.1 XRD analysis............................................................................................................ 62 V.2.2.2 Crystallite size and compressive stress .................................................................... 64 V.2.3 Optical properties ........................................................................................................ 65 V.2.4 Electrical resistivity ...................................................................................................... 67 V.3 the effect of annealing temperature ........................................................................... 68 V.3.1 experimental details .................................................................................................... 68 V.3.2 structural properties ................................................................................................... 68 V.3.2.1 XRD analysis............................................................................................................ 68 V.3.2.2 Crystallites size ....................................................................................................... 63 V.3.3 Optical properties ....................................................................................................... 71 V.3.4 Electrical resistivity ..................................................................................................... 72 General Conclusion and future work. ......................................... 74 References ................................................ |
| En ligne : | http://thesis.univ-biskra.dz/id/eprint/4150 |
Disponibilité (1)
| Cote | Support | Localisation | Statut |
|---|---|---|---|
| TPHY/74 | Théses de doctorat | bibliothèque sciences exactes | Consultable |
