Investigation of the Microscopic Characteristics of Ultrathin Gold Layers

Abstract

This master's dissertation investigates the microscopic characteristics of ultrathin gold films. The study employs angle-variable spectral ellipsometry and Drude theory to assess the relaxation times and plasma frequencies of gold films with thicknesses varying between 3 and 47 nm. To fabricate continuous and homogeneous ultrathin gold films, a novel technique is applied: an additional seed layer based on Cu oxide is deposited on a commercial Si-SiO$_2$ substrate. The research presents data on the complex optical constants and dielectric functions in the 240-1700 nm wavelength range of the ultrathin Au films, derived by fitting the ellipsometric parameters with the Fresnel isotropic and anisotropic models. A noteworthy finding of this study is the contrasting behavior of the real and imaginary parts of the dielectric function with increasing film thickness. This comprehensive analysis also demonstrates that consideration of confinement effects and the Fresnel model's isotropic/anisotropic nature is imperative to extract the optical properties of these films successfully. The overall insights from this dissertation offer significant contributions to the understanding and application of ultrathin gold films.

Date of Award	1 Aug 2024
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Alexander Grigorenko (Supervisor) & Vasyl Kravets (Supervisor)