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Spectroscopic ellipsometry is the technique of choice to characterise thickness and refractive indices of thin layers. Atmospheric Ellipsometry Porosimetry (EPA) measures the change of the optical properties and thickness of the materials during adsorption and desorption of wet air at atmospheric pressure. Concentration of humidity changes at each step of measurement from dry air to saturated air.
This technique becomes an effective method to characterize porosity, pore size distribution (PSD) and Young modulus of porous thin films. Detailed description of the technique will be exposed in the paper and several meso-porous films (with pore size larger than 1nm) using the Kelvin formalism will be presented. The porosity of the layer ranges from few percent up to 40%.
As it is an optical method, it is non contact, non destructive, fast and room temperature method. It does require low pressure or any preparation of sample.
Using this technique, it becomes possible to characterize in term of porosity and pore size distribution the effect of thermal curing of TiO2 which is widely used in the photocatalysis and photovoltaic industries. The influence of the extraction of CTAB in TEOS matrix (CS 10 material) with ethanol and thermal treatment will also be presented in this paper.
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