Optical properties of gold nanoparticles on heavily-doped Si substrate synthesized with an electrochemical process

Abstract

Gold nanoparticles on a heavily-doped Si substrate were synthesized through direct electroreduction of bulk AuCl‾₄ ions. The optical properties of the nanoparticles were determined from ellipsometric analysis. The Lorentz-Drude model was used to represent the effective dielectric function of the gold nanoparticles. A prominent peak at ~ 1.7 eV is identified in the imaginary part 2, which is attributed to the surface plasmon resonance. There are also two minor peaks located at ~ 3.1 and ~ 4.2 eV, respectively, which are related to the interband transitions. The interband transitions are greatly suppressed, which could be due to the modified lattice structures of the nanoparticles.