Effect of molecular layers on charge transport in nanowires

Stable ultrathin gold nanowires (Au NWs, 2nm diameter) were produced using wet chemical synthesis, which implied oleylamine molecules, and subsequently assembled onto gold electrodes. Transport properties of fabricated structures were studied using the noise spectroscopy technique. Lorentzian-shaped components were revealed in the noise spectra. The characteristic frequencies of these components were independent of the bias applied, which thus excludes self-heating of the nanowires. Noise peculiarities were shown to be the result of the presence of oleylamine molecules on the NWs. The evidence of oleylamine on the surface of the fabricated structures was confirmed by high-resolution transmission electron microscopy. Organic monolayers can strongly influence charge properties in nanosystems. These results should be taken into account in designing nanowire-based devices for molecular electronics.