Analytic determination of n, k and d of two-dimensional materials by ellipsometry and reflectivity

Simple diagnostics possibilities of two-dimensional absorbing materials on dielectric substrates by ellipsometry or by integrating ellipsometric and reflectance measurements are analyzed. The analysis is based on the original analytical formulas for ellipsometric angles obtained in the framework of a long-wavelength approximation. A valuable feature of this approach lies in the fact that the traditional model-based regression analysis is not used for data handling-new inversion formulas allow direct calculation of optical constants and thickness of a two-dimensional absorbing material upon a transparent substrate. In practice, it is of first importance that there exists no need of initial guesses for the desired parameters. The presented method is tested using a numerical simulation.