Relation between the optical properties of composite Si3N4 thin films with embedded Cu clusters and the clusters morphology: Irradiation effects

Abstract

Ion beam sputtering codeposition has been used to elaborate ceramic–metal (cermet) composite thin films consisting of copper nanoclusters embedded in an amorphous Si3N4 matrix. As prepared, the clusters have a size smaller than 3 nm and postirradiation by high energetic Ar+ ions leads to an homogenization of the clusters’ morphology and an increase of the clusters’ size to an average diameter of 4.5 nm. This work deals with the relation between the morphology of the clusters, characterized by extended x-ray absorption fine spectroscopy and grazing incidence small angle x-ray scattering, and the optical properties (obtained by spectroscopic ellipsometry) of the cermets, which are classically modeled with the help of the effective medium theory. In the case of the as-prepared sample, the Bruggeman effective medium theory has been successfully used. This comes from the fact that the clusters are sufficiently close to each other to create mutual interactions. On the other hand, the morphology of the postirradiated film is in agreement with the hypothesis made by the Maxwell–Garnett effective medium theory, and a resonance peak appears due to the surface plasmon excitation whose position depends on the cluster size.

Characterization of Ceramics by X‐Ray and Neutron Small‐Angle Scattering

“…(2) Sintering, Cavitation, and Damage Effects SAS methods have addressed a range of void characterization issues in ceramic materials development, [5][6][7][8][9][10][11][40][41][42]86,[126][127][128][129][130][131][132][133][134][135][136][137][138][139][140][141][142] such as elucidating aspects of the pore evolution during sintering, or quantifying the void defect and cavitation morphology that develops as a result of creep or other damage effects. The evolution of the void size distribution during the sintering and densification of nanostructured ceramics and gels has been comprehensively studied by both SANS and SAXS.…”

Optical and Physical Properties of Cobalt Oxide Films Electrogenerated in Bicarbonate Aqueous Media

“…Spectroscopic ellipsometry (SE) is one of the most convenient, accurate, surface-sensitive, and nondestructive optical techniques to investigate the optical properties (complex refractive index, N ) n -ik; n is the refractive index, k is the extinction coefficient), the microstructure, and the thickness of thin films. [36][37][38][39][40] Figure 5 presents the XP spectrum of cobalt substrate, recorded after polishing. The peak at 778.3 eV is assigned to Co 2p 3/2 binding energy of bare cobalt, 41 while other peaks are characteristic of the XP signature of CoO (see Figure 3c).…”

Relations between the optical properties of Cu–Ag:Si3N4 nanocermets and the microstructure of the metallic nanoclusters

“…The small distance and the faint intensity of this peak could be due to a shell of light atoms, either Si or N, around Cu. The Si 3 N 4 matrix being amorphous [15], the hypothesis of metallic atoms in substitution or in insertion in this Si 3 N 4 matrix seems clearly the more likely. In any case, this pseudoradial distribution shape cannot be characteristic of pure metal or alloyed metallic species.…”