Evaluation of Thermal Conductivity of a Multi-Walled Carbon Nanotube Using the ΔVgsMethod

Thermal conductivity of a multi-walled carbon nanotube (MWNT) was evaluated using the ΔVgs method for the first time. MWNTs were prepared in pillars, and the pillars were placed on two aluminum nitride (AlN) substrates. An AlGaN/GaN high electron mobility transistor (HEMT) chip, which was set on an AlN substrate, was used as a thermometer and as a thermal source. The thermal resistance of the sample was measured using the ΔVgs method. From the thermal resistance of MWNT pillars, we succeeded in evaluating the thermal conductivity of a MWNT pillar and that of a MWNT as high as 74.2 and 950 W/(mK), respectively. The thermal conductivity of MWNTs evaluated in this study is much higher than that of usual metals. We confirmed that MWNTs are promising materials for heat dissipation problems.