Characterisation of nanodimensional structures using spectroscopic ellipsometry

In this paper, using spectroscopic ellipsometry we studied the optical properties of thin films, nanocrystals and carbon nanotubes in UV-VIS-NIR range. With a three-phase model, we calculated the thickness of the SiO2 film on a silicon substrate. Using the model for multilayer structure together with the Bruggeman effective medium approximation we determined the existence of roughness on a glass substrate and we calculated the thickness of that layer. We also determined the thicknesses of 12 layers, Si3N4 i SiO2 deposited alternately on a glass substrate. The dielectric function of CeO2 nanocrystal was modeled using the Tauc-Lorentz model and we calculated the value of the energy gap for this material. By analyzing the ellipsometry spectra for the carbon nanotube layer on the silicon substrate, we measured the real and imaginary part of its dielectric function.