Characterization on Percolation of Nanostructured Silver Films by the Topological Properties of Spectroscopic Ellipsometric Parameter Trajectories

Abstract

Silver (Ag) films with different nanostructures were prepared by electron beam evaporation and characterized by spectroscopic ellipsometry in combination with X-ray diffraction and field emission scanning electron microscopy (FESEM). The percolation threshold and the nanostructures of Ag films can be deduced from the measured ellipsometric parameters (Ψ, Δ). According to the different topological properties of (Ψ, Δ) trajectories, the percolation threshold of Ag films was determined to lie between the coverage of 66 and 79.6%. The result was further confirmed by the plus−minus sign of the real part of the dielectric function in the infrared. Silver particles, coalescence, networks, and continuous nanostructures were clearly identified from the topological properties of the tangent azimuth of (Ψ, Δ) trajectories, which were verified by the FESEM results. This work is useful for monitoring the fabrication of nanostructure materials in the industry and research field. In addition, it has potential applications on the recognition of micro−nanostructures in the artificial intelligence field.

Interpretation of Reflection and Colorimetry Characteristics of Indium-Particle Films by Means of Ellipsometric Modeling

“…For samples with a bimodal particle size distribution, ellipsometry can directly model and distinguish the contributions of complicated structures to the overall response [ 24 ]. Furthermore, percolation is expected as the particles grow in size, which can be determined simply by measuring the ellipsometric parameters [ 25 ]. The ellipsometric modeling extracts the effect on the optical responses [ 22 , 24 , 25 ].…”

“…Furthermore, percolation is expected as the particles grow in size, which can be determined simply by measuring the ellipsometric parameters [ 25 ]. The ellipsometric modeling extracts the effect on the optical responses [ 22 , 24 , 25 ]. Such structure-dependent optical responses influence the reflectance spectrum consequently.…”

Optical Characteristics of Silver Thin Films from Island to Percolation in the Ultra-Wide Infrared Spectral Range

“…The optical properties of Ag thin films play an extremely important role in these applications. Thus, most previous investigations mainly concentrated on the surface plasmon polaritons (SPPs) of Ag films in the visible and near-infrared (VIS-NIR) regions [12][13][14][15][16][17][18][19][20][21][22]. By contrast, little attention has been paid to the optical characteristics of Ag thin films in the mid-infrared (MIR) and far-infrared (FIR) regions.…”