Study of the optical properties of silver nanoparticle layers and Si‐based nanostructure layers

Abstract

Ellipsometric spectra (λ = 250–900 nm) of surface layers were for the first time obtained in three stages of the catalytic etching of silicon, used to fabricate wire‐like nanostructures. Self‐assembled silver particles deposited with chemical method on the silicon surface form a discontinuous layer with its own complex dielectric function ϵ, which is independent of the radiation incidence angle (at 50–70 degrees relative to the normal to the surface) and differs from ϵ of the bulk silver structure. The variation of the imaginary part of the pseudodielectric function, ϵ2, of the layer of silicon nanowire (SiNW) sprouts was studied. At the minimum catalytic etching duration, the thickness of the rough SiNW layer being formed is comparable with the thickness of the layer of preliminarily deposited silver. With increasing etching duration, a low‐refractive SiNW layer is formed with a thickness of 111 nm and void fraction of 33–78%, found in Bruggeman's effective medium approximation. The experimental data obtained with a spectroscopic ellipsometry and their interpretation made it possible to determine specific features of nanostructures at the earliest interval silicon etching time.