Vertically aligned carbon nanotube (CNT) arrays have been explored as advanced thermal interface materials because of their compliance and high cross-plane thermal conductivity. Our previous work showed that a CNT array directly bridging two surfaces by dry contact had a surface-surface interface resistance of order of 10 m2-K/MW. With an indium bonding layer, the interface thermal resistance was reduced by a factor of ten. Therefore, a more sensitive measuring system is needed to accurately determine the thermal resistance. In this paper, we achieved a higher sensitivity measurement by applying the phase sensitive transient thermo-reflectance technique to a front side heating and detecting system. A detailed analysis is presented. We used this technique to characterize a 71-μm long CNT array with packing density of 9.4 ± 1.4%. The CNT array was sequentially wetted with chromium/gold films and was bonded to a glass surface with an indium bonding layer. We found that the CNT array-surface interface resistance is 0.35 ± 0.11 m2-K/MW and the cross-plane thermal conductivity of CNT array is 94 ± 40 W/m-K.

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