Non-contact investigation of metal-nanostructure conductivity

The dynamic conductivity of metal nanostructures is determined by material properties, the morphology in the volume of the nanostructure, its shape and its size, and by the structure and the chemical composition at the surfaces. IR-spectroscopic investigation of dynamic charge transport allows a distinction between such contributions. We performed in-situ IR spectroscopic measurements of metal ultrathin (<10 nm) films on non-metal substrates. Our thin-film model based calculations of IR spectra indicate depolarisation for inhomogeneous films, quantum confinement for homogeneous films, adsorbate induced charge carrier relaxation and charge transfer at thin film surfaces, and they provide a measure of the dc-conductivity of these nanosized metals in a non-contact fashion.