Size dependence of the dielectric function of silicon-supported plasmonic gold nanoparticles

作者：Losurdo Maria^*; Giangregorio Maria M; Bianco Giuseppe V; Suvorova Alexandra A; Kong Charlie; Rubanov Sergey; Capezzuto Pio; Humlicek Josef; Bruno Giovanni

来源：Physical Review B, 2010, 82(15): 155451.

DOI：10.1103/PhysRevB.82.155451

Gold nanoparticles (NPs) are directly deposited on a Si(111) substrate by Ar sputtering to provide a semiconductor-based plasmonic platform. The Au NPs are characterized by interband transitions at energies above 2.5 eV, whose tails extend into the surface-plasmon resonance (SPR) region, hence affecting the SPR energy, amplitude, and broadening. Herein, we report the experimental evidence of the size dependence of the interband transitions for Au NPs supported on silicon and sapphire substrates by exploiting plasmonic ellipsometry. Providing the size dependence of the dielectric function of Au NPs in the extended spectral range of 190-1700 nm, and discussing the interconnection between the SPR and the interband transitions, this study as a whole represents a step ahead in the perspective of a better understanding of nanosize effect on optical properties and standardization of nanoparticles dielectric functions to rely on more accurate modeling of NPs behavior.

• 出版日期2010-10-28