Skip to Main content Skip to Navigation
Theses

Etude de la croissance de couches minces de TiO2 et TiO2 / SiO2 par torche plasma micro-ondes à la pression atmosphérique

Abstract : An open air chemical vapour deposition process, using an axial injection torch (TIA) was developed for the deposition of TiO2 and TiO2 / SiO2 thin films. The effects of deposition parameters such as the torch-to-substrate distance (d), the incident microwave power and the titanium precursor (TTIP) flow rate on (i) the morphology and (ii) the crystalline structure of the layers were investigated . Since these layers are applied in the field of heterogeneous photocatalysis, the process optimization aimed to obtain a high surface area and to promote the growth of anatase phase. Besides the study of the plasma phase (by optical emission spectroscopy) and the plasma - surface interactions, a complete characterization of the film deposited in the optimized conditions enabled to provide a growth mechanism in the static mode. It was suggested that (i) the central zone of the deposit results from surface reactions and (ii) the peripheral zone results from the surface agglomeration of nanoparticles previously formed in plasma phase. Finally, the deposition of mixed oxides TiO2 / SiO2 was investigated over a wide range of Si / Ti ratios. It has been shown that whatever the torch-to-substrate distance, three phases were detected: SiO2, TiO2 and TixSiyOz. When d = 10 mm, the TiO2 layer is crystallized in the anatase form, whereas when d = 30 mm, the entire layer is amorphous. The addition of a small amount of silica (about 3%) to the anatase TiO2 increased the photocatalytic activity of about 15%. A preliminary study consisting in the deposition on large areas by moving the substrate, opens the way for wider applications.
Document type :
Theses
Complete list of metadata

https://tel.archives-ouvertes.fr/tel-01251861
Contributor : Abes Star :  Contact
Submitted on : Wednesday, January 6, 2016 - 6:52:05 PM
Last modification on : Thursday, May 17, 2018 - 4:45:03 AM
Long-term archiving on: : Thursday, April 7, 2016 - 4:16:56 PM

File

2015LIMO0088.pdf
Version validated by the jury (STAR)

Identifiers

  • HAL Id : tel-01251861, version 1

Collections

Citation

Yoan Gazal. Etude de la croissance de couches minces de TiO2 et TiO2 / SiO2 par torche plasma micro-ondes à la pression atmosphérique. Matériaux. Université de Limoges, 2015. Français. ⟨NNT : 2015LIMO0088⟩. ⟨tel-01251861⟩

Share

Metrics

Record views

762

Files downloads

841