Analysis of Optical and Structural Properties of Sol–Gel TiO2 Thin Films

Titanium dioxide (TiO2) is widely used in various industries (cosmetics; painting; solar cells; used-water reprocessing; electro-chromatic systems; etc.). It exists under different crystalline forms: rutile, anatase, and brookite. We have prepared our samples using an alcoholic solution of Tetra-buthylorthotitane, hydrolysed in a water/alcohol/acid mixture. The solution thus prepared was deposited by a sol–gel method on an ITO substrate. The layers undergo a heat treatment at temperatures varying from 300 with 500°C, and various dippings. DRX analysis of our thin films of TiO2 shows that the titanium oxide starts to crystallize starts from the temperature of annealing 350°C. The structure obtained is anatase. At higher temperatures (400 and 450°C), and for a number of layers (dipping iterations) increasing from 4 to 9, we observe in addition to anatase, the formation of brookite. The intensities corresponding to the lines characteristic of anatase (101) and brookite (111) increase with temperature. This increase in the intensities of the peaks is interpreted as due to an increase in size of the grains (nanocrystals) of titanium oxide with the increase in the annealing temperature. The Raman spectra confirm the presence of titanium oxide starting from the temperature 350°C, the peaks characteristic of anatase (tetragonal) appear near bands centred around 153 and around 193cm-1. For the higher temperatures (400 and 450°C) we note also the formation of brookite which corresponds to the wavelength 650 cm-1. The calculated size of the grains varies from 11.9 to 17.1nm for anatase and from 25 to 10.2nm for brookite. The index of refraction (n), and porosity (p) are calculated starting from the measured transmission spectra, and vary between 1.63 and 2.59 for n, and from 3.5 to 68.7% for porosity.Titanium dioxide (TiO2) is widely used in various industries (cosmetics; painting; solar cells; used-water reprocessing; electro-chromatic systems; etc.). It exists under different crystalline forms: rutile, anatase, and brookite. We have prepared our samples using an alcoholic solution of Tetra-buthylorthotitane, hydrolysed in a water/alcohol/acid mixture. The solution thus prepared was deposited by a sol–gel method on an ITO substrate. The layers undergo a heat treatment at temperatures varying from 300 with 500°C, and various dippings. DRX analysis of our thin films of TiO2 shows that the titanium oxide starts to crystallize starts from the temperature of annealing 350°C. The structure obtained is anatase. At higher temperatures (400 and 450°C), and for a number of layers (dipping iterations) increasing from 4 to 9, we observe in addition to anatase, the formation of brookite. The intensities corresponding to the lines characteristic of anatase (101) and brookite (111) increase with temperature. This increase in the intensities of the peaks is interpreted as due to an increase in size of the grains (nanocrystals) of titanium oxide with the increase in the annealing temperature. The Raman spectra confirm the presence of titanium oxide starting from the temperature 350°C, the peaks characteristic of anatase (tetragonal) appear near bands centred around 153 and around 193cm-1. For the higher temperatures (400 and 450°C) we note also the formation of brookite which corresponds to the wavelength 650 cm-1. The calculated size of the grains varies from 11.9 to 17.1nm for anatase and from 25 to 10.2nm for brookite. The index of refraction (n), and porosity (p) are calculated starting from the measured transmission spectra, and vary between 1.63 and 2.59 for n, and from 3.5 to 68.7% for porosit

Characterization of structural, optical and electric properties of TiO2 thin films prepared by reactive DC magnetron sputtering.

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TIO2 thin films prepared by sol-gel method for waveguiding applications

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µ-structuration par ablation laser nanoseconde de couches minces de TiO2

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