Implications of catalyst control for carbon nanotube based thermal interface materials

Abstract

We report on the characterization of a carbon nanotube (CNT) based thermal interface material grown by chemical vapor deposition on catalysts formed by a micelle templating method. The micelle templating method allows for controllable diameter and density in the CNT array that is not easily achieved by other techniques. In this work, we characterize the activity of the catalyst to be at least 10% by a root-counting method. This activity differs from that reported in other works, although the disparity may be largely explained by understanding the approximations in other characterizations. Characterization of thermal interface resistance shows nonmonotonic dependencies on length and catalyst/nanotube density, with optimum values of approximately 0.08 K cm2/W. This exceeds that characterized by others in the literature for a single CNT film interface and state of the art thermal greases. Dependencies on length and density are explained by considering how the compliancy of the CNT array is impacted by these variables.