Compliance properties study of carbon nanofibres (CNFs) array as thermal interface material

Carbon nanostructures, such as carbon nanotubes (CNTs) and carbon nanofibres (CNFs), have the potential, owing to their high thermal conductivity, to be successfully employed in micro- and opto-electronic devices for effective integrated circuits cooling. We address the CNT/CNF compliance properties and their effect on the thermal performance of CNT/CNF based thermal interface materials (TIMs). We synthesized vertically aligned CNT/CNF arrays on a Cu substrate by using the plasma enhanced chemical vapour deposition technique. Cu was used also to fill in the gaps between the CNT/CNF, and electrochemical deposition (ECD) was employed for this purpose. The number and the length of the CNT/CNFs protruding out of the Cu matrix were controlled by controlling the time of the ECD deposition. The thermal properties of CNT/CNF and CNT/CNF-Cu composites were characterized by photothermal method. We found that the CNT/CNF structural compliance with respect to the axial ('through-thickness') loading strongly affects the CNT/CNF array performance as a TIMs.