High conductivity carbon nanotube wires from radial densification and ionic doping

Application of drawing dies to radially densify sheets of carbon nanotubes (CNTs) into bulk wires has shown the ability to control electrical conductivity and wire density. Simultaneous use of ${\text{KAuBr}}_4$ doping solution, during wire drawing, has led to an electrical conductivity in the CNT wire of $1.3\times {10}^6\text{S}/\text{m}$ . Temperature-dependent electrical measurements show that conduction is dominated by fluctuation-assisted tunneling, and introduction of ${\text{KAuBr}}_4$ significantly reduces the tunneling barrier between individual nanotubes. Ultimately, the concomitant doping and densification process leads to closer packed CNTs and a reduced charge transfer barrier, resulting in enhanced bulk electrical conductivity.