Conductivity of nanometer-sized ion tracks in diamond-like carbon films

Abstract

Amorphous diamond-like carbon films were irradiated with high-energy heavy ions like 1 GeV uranium or 340 MeV gold. The large energy deposition along the ion track leads to a transformation of the material from insulating diamond-like to conducting graphite-like carbon. The ion tracks form thin straight channels (nanowires) with a diameter of approximately 8 nm and a conductivity of the order of 1–10 S/cm. The conductivity in the tracks is up to eight orders of magnitude larger than in the surrounding material. The surface topography and the conduction properties of these channels were studied with an atomic force microscope.