Charge transport mechanisms in the arrays of multi-walled carbon nanotubes

Abstract

Electronic and magnetotransport properties of carbon nanotubes have attracted much attention due to they importance in verification of existing theories of modern condenced matter physics and number of possible applications. Single-walled carbon nanotubes (SWCNTs) have unique structure and show metallic or semiconducting properties in dependence of their diameter and chirality. Multi-walled carbon nanotubes (MWCNTs) are more complicated systems. They consist of a several shells of different diameter and chirality. Due to weak coupling between the shells the conductivity in a bulkcontacted MWCNTs is defined mostly by the outermost shells. For possibility of commercial manufacturing of carbon nanotubes based sensors and devices the development of fabrication methods of carbon nanotube arrays is of great importance. The intertubes barriers and defects play an essential role in the electrical transport properties of the carbon nanotube arrays. Therefore different charge transport mechanisms can be observed in the arrays of nanotubes: metallic conductivity, variable range hopping (VRH), weak localization (WL), fluctuation induced tunneling. Combination of various mechanisms is possible as well. Different types of moфhology of carbon nanotubes arrays are proposed: bundles, networks, fibers, mats etc. We present here magnetotransport properties of the thing layers of MWCNTs.