The authors report here on the optical response and extraction of the morphological properties of three sizes of self-assembled nearly hexagonal arrays of gold (Au) nanoparticles (NPs), deposited on the native oxide on c-Si. The arrays were prepared by templating gold NP growth with self-assembled cylindrically organized block copolymer thin films, with consecutive removal of the polymer matrix by plasma etching. The particle sizes were controlled by using block copolymers of different molecular weights when assembling the templates. The resulting gold nanostructures were characterized by scanning probe microscopy. Spectroscopic ellipsometry was used to record the opticalresponse of the samples, and the modeling of the spectra and the extraction of morphological parameters were performed using a modification of the Bedeaux–Vlieger formalism implemented in GRANFILM. The modeling issues upon the introduction of a thin intermediate (oxide) layer between the particle and the substrate are discussed in detail, and a solution to the model procedure is proposed. The particles were modeled as truncated oblate Au spheroids in a hexagonal lattice on the native oxide on c-Si. The model fit converged to a solution indicating that the particles present a low wetting of the native oxide substrate, with parameters describing the particles and lattice in good correspondence with AFM. The extended GRANFILM model simulations are also supported by finite element modeling.< Réduire