Local investigation of the electronic properties of size-selected Au nanoparticles by scanning tunneling spectroscopy

The relationship between the structural/morphological and electronic properties of size-selected gold nanoparticles was investigated using scanning tunneling microscopy and spectroscopy. The nanoparticles were synthesized by inverse micelle encapsulation and were dip-coated on TiO2∕Ti(15 nm)∕Si(111). Annealing in vacuum to 500°C resulted in the removal of the polymer and the formation of an ultrathin TiC support. Significant changes in the electronic local density of states (LDOS) of the nanoparticles, in particular, the onset of nonmetallic behavior, were observed with decreasing particle size. The nanoparticle-support interactions were studied and evidence for substrate-induced modifications in the LDOS of interfacial gold atoms is found