| Abstract [eng] |
A lot of novel materials are created everyday. It is desired to measure their parameters in fast, accurate and non-destructive way. Some of the materials are expensive, complicated or time consuming to make. Thus destruction of sample only for measurement of its characteristics is unacceptable. In this case, new non-destructive optical measurement techniques are highly preferable. Ellipsometry technique has developed rapidly over the last few decades. At first it was very limited, giving the results only for two unknown variables, e.g. refractive index of material at one chosen wavelength and the thickness of film, and requiring educated guess. After developing it further to variable angle and spectroscopic ellipsometry, it became very flexible technique. In this project, spectroscopic ellipsometry technique is applied for investigation of nanoporous and nanocomposite materials. The first type of samples is porous anodized alumina and the second type is copper nanoparticles embedded in diamond like carbon matrix. The samples were investigated at 3-9 microspots and at 10 different angles of incidence. In order to extract characteristic parameters of the samples, theoretical curves of ellipsometric parameters were fitted to experimental ones using optical model describing the samples. Various effective medium approximations and dispersion laws for description of corresponding materials were tested to obtain the best fit. The derived thickness values are in good agreement with the ones measured with scanning and transmission electron microscopes. The obtained volume concentrations of pores in anodized alumina samples or copper filler in diamond like carbon nanocomposite films have the same tendencies as pore diameter and mass density for corresponding samples obtained using alternative analytical methods. The optical properties, such as dispersion curves of refractive index and absorption coefficient, were also derived and investigated. |
