Thermal Properties of Metal-Coated Vertically-Aligned Single Wall Nanotube Films

Owing to their extraordinarily high thermal conductivities, carbon nanotubes (CNTs) are promising for use in advanced thermal interface materials (TIMs). While there has been much previous research on carbon nanotube thermal properties, there are little data for aligned films of single wall nanotubes. This paper measures the thermal interface resistances of metal-coated vertically-aligned single wall CNT (SWNT) arrays using a nanosecond pump/probe thermoreflectance technique. The data capture the vertical variation of CNT thermal properties including their interface resistances. The data show the total thermal resistance of the TIM is R"_swnt,tot=1.2 times 10^-5 m² KW^-1, and that the CNT-metal interface resistance strongly reduces the effective vertical thermal conductivity. An approximate model shows that the evaporated metal film contacts only a small fraction of the CNTs. Based on the conclusions of the model, the individual CNT-metal contact conductance is h_cnt-metal,a=6.6 times 10⁷ Wm^-2K^-1 which is quite good. Increasing the number of CNT-substrate contacts is a very promising approach for improving the thermal performance of CNT-based interface materials