Thermal boundary resistance and temperature dependent phonon conduction in CNT array multilayer structure

• Thermal boundary resistances of CNT array are reconstructed using 3ω method.
• Phonon transport mechanism of SWCNT captures the temperature dependency.
• Temperature dependence of TBR suggests phonon inelastic scattering.

This work uses 3ω thermometry to separate interface resistances with growth and opposing substrates for aligned MWCNT array between 280 and 380 K. The measured DLC-MWCNT and MWCNT-Si substrate thermal resistances range between 5 and 12 mm2 K W−1 and 0.8–2.1 mm2 K W−1, respectively. The temperature dependency of the measured heat capacity is well consistent with the predictions. The nonlinear temperature dependence of the interface resistance suggests an important role of phonon inelastic scattering including all the acoustic bands and greatly enhanced by the low frequency optical phonon bands with high velocity. The phonon transport physical mechanism of an isolated SWCNT well captures the temperature dependency of thermal capacity of the MWCNT array and only approximately captures the temperature dependency of thermal boundary resistance in the current experimental temperature range.