INVESTIGADORES
SCAFFARDI Lucia Beatriz
artículos
Título:
DETERMINATION OF THICKNESS-DEPENDENT DAMPING CONSTANT AND PLASMA FREQUENCY FOR ULTRATHIN AG AND AU FILMS: NANOSCALE DIELECTRIC FUNCTION
Autor/es:
LUIS J. MENDOZA HERRERA; MYRIAN C. TEBALDI; LUCÍA B. SCAFFARDI ; DANIEL C. SCHINCA
Revista:
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
Editorial:
ROYAL SOC CHEMISTRY
Referencias:
Lugar: CAMBRIDGE; Año: 2022 p. 1 - 10
ISSN:
1463-9076
Resumen:
This paper is devoted to determine an analytical expression for the thickness dependent complexdielectric function for the case of Ag and Au thin films. Free and bound electron contributions aredealt with independently.Using Drude model for the former and taking experimental refractive index values for Ag and Authin films, we apply a previously developed method to determine for the first time damping constantand plasma frequency parameters for specific film thicknesses. Fitting separately each one of theseparameters allowed us to to find an analytical expression for their dependence on arbitrary filmthickness and consequently for the free electron contribution.Concerning bound electrons, its contribution for small wavelengths is the same for all analyzedthicknesses and may be set equal to the bulk bound contribution. Taking these facts into account,the complex dielectric function is rewritten analytically, in terms of bulk dielectric function pluscorrective film thickness dependent terms.From the fitting process for the damping constant we determine that electron scattering at the filmboundary is mainly inelastic for both silver and gold thin films. It is also shown that, in accordancewith theoretical studies, plasma frequency shows a red shift as the film thickness decreases.