High-Density Carbon Nanotube Forest Growth on Copper Foil for Enhanced Thermal and Electrochemical Interfaces

Vertically aligned carbon nanotubes (CNTs) - also called CNT forests - are attractive for use in battery electrodes, capacitive sensors, thermal interface materials, and many other applications. However, for practical use in most cases, the CNT forest must be dense and have mechanically robust, low-resistance electrical contact with the substrate. Fulfilling those requirements is often challenging, particularly when copper is used as the substrate material. Herein, we report production of tall (270 μm maximum height) CNT forests on copper foils, by chemical vapor deposition by combining a supported catalyst structure with gaseous carbon preconditioning of the catalyst prior to film dewetting and annealing. Incorporation of tungsten in the catalyst support prevents diffusion of the iron catalyst into the underlying copper and promotes the formation of a high density population of catalyst particles. We find that the electrical resistance of the CNT forest scales with height, and correlated with X-ray scattering measurements of CNT density.