Fine Structure in Energy Spectra of Ultrasmall Au Nanoparticles

TL;DR

This study investigates the discrete energy levels in ultrasmall gold nanoparticles (2-5 nm) through tunneling measurements, revealing clustered resonances that become more prominent as particle size decreases.

Contribution

It provides new insights into the fine structure of energy spectra in ultrasmall gold nanoparticles, highlighting the splitting of tunneling resonances not observed in larger particles.

Findings

Resonant tunneling via discrete energy levels observed

Lowest energy resonances split into clusters of 2-10 subresonances

Splitting effects increase with decreasing particle size

Abstract

We have studied tunneling into individual Au nanoparticles of estimated diameters 2-5 nm, at dilution refrigerator temperatures. The I-V curves indicate resonant tunneling via discrete energy levels of the particle. Unlike previously studied normal metal particles of Au and Al, in these samples we find that the lowest energy tunneling resonances are split into clusters of 2-10 subresonances. Such effects appear to be increasingly important in smaller grains, as might be expected from the larger characteristic energies.