Amorphization of Cu nanoparticles: effects on surface plasmon resonance

Abstract

Crystalline copper nanoparticles (NPs) were formed in silica by multi-energy MeV ion implantations and then transformed to amorphous NPs by irradiation with 5 MeV Sn3+ ions. Optical absorptionspectra of both the phases were evaluated in the ultra-violet to near-infrared regions. Compared with corresponding crystalline NPs of the same mean diameter, the amorphous NPs showed a low-energy shift of the surface plasmon resonance around 2.2 eV and less prominent absorptionstructure around 4 eV. These differences are explained by a strongly reduced electron mean-free-path in the amorphous NPs due to the loss of lattice periodicity. Show more