Dielectric function of a polymer brush functionalized with gold nanoparticles determined from spectroscopic ellipsometry

Spectroscopic ellipsometry is a powerful technique for measuring the thickness and dielectric function of thin films deposited upon optically reflective surfaces. The dielectric function determines the material optoelectronic properties, however its ellipsometric measurement is challenging in cases when the film thickness and its exact structure in terms of phases and their optical properties, are unknown. The present paper discusses several models of film dielectric function, which may be considered for fitting the ellipsometric spectra of a poly(N-ispropylacrylamide) brush grown at silicon surface and functionalized with gold nanoparticles.