Optical properties of a disordered array of self-organized Ag nanoparticles on SiO$_2$/c-Si surface

In this work, a disordered array of self-organized hemispherical Ag nanoparticles on a SiO$_2$/Si surface was studied. The structures were obtained by a simple, reproducible and low-cost method based on the reduction of Ag from solution on the silicon surface, followed by annealing in an O$_2$ atmosphere at 350$^\circ$C. Experimental data are analyzed using the Bruggeman effective medium approximation and Lorentz oscillators which determined the volume fraction of Ag and plasmon resonances positions, respectively. The numerical spectral positions of localized surface plasmon resonances are in good agreement with the data obtained by spectroscopic ellipsometry.