Electrical properties measurements on individual carbon nanofibers by scanning spreading resistance microscopy

Abstract

Vertically aligned 850-nm-long carbon nanofibers (CNFs) are grown on a titanium nitride (TiN) layer by a radio-frequency plasma system at 560 °C. Electrical properties of individual CNFs are statistically determined by a current sensing atomic force microscopy mode. An interpretation based on electrical contact resistance model classically used to describe macroscopic observations, combined with a semiclassical approach commonly used for such nano-objects, is proposed here to explain dispersion in obtained values. Roughness of the TiN layer is responsible for this dispersion by varying contact surface between CNF and the TiN layer, while interface oxidation equally affects the transport by adding a barrier at the interface. Some CNFs exhibit very low resistances (few kilohms), implying that good contact is obtained between the nanofiber and the substrate, while others CNFs exhibit high resistance, attributed to local poor electrical contacts between CNFs and TiN layer.