Dense Vertically Aligned Multiwalled Carbon Nanotube Arrays as Thermal Interface Materials

Abstract

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> Carbon nanotube (CNT) arrays are being considered as thermal interface materials (TIMs). Using a phase sensitive transient thermo-reflectance technique, we measure the thermal conductance of the two interfaces on each side of a vertically aligned CNT array as well as the CNT array itself. We show that the physically bonded interface by van der Waals adhesion has a conductance <formula formulatype="inline"><tex>$\sim$</tex></formula>10<formula><tex>$^{5}$</tex> </formula> W/m<formula><tex>$^{2}$</tex></formula>K and is the dominant resistance. We also demonstrate that by bonding the free-end CNT tips to a target surface with the help of a thin layer of indium weld, the conductance can be increased to <formula formulatype="inline"><tex>$\sim$</tex> </formula>10<formula><tex>$^{6}$</tex></formula> W/m<formula> <tex>$^{2}$</tex></formula>K making it attractive as a TIM. </para>