Measuring the Thermal Conductivity of a Single Carbon Nanotube

Although the thermal properties of millimeter-sized carbon nanotube mats and packed carbon nanofibers have been readily measured, measurements for a single nanotube are extremely difficult. Here, we report a novel method that can reliably measure the thermal conductivity of a single carbon nanotube using a suspended sample-attached $T$-type nanosensor. Our experimental results show that the thermal conductivity of a carbon nanotube at room temperature increases as its diameter decreases, and exceeds $2000\mathrm{W}/\mathrm{mK}$ for a diameter of 9.8 nm. The temperature dependence of the thermal conductivity for a carbon nanotube with a diameter of 16.1 nm appears to have an asymptote near 320 K. The present method is, in principle, applicable to any kind of a single nanofiber, nanowire, and even single-walled carbon nanotube.

Figure 1

Schematic diagram of the nanosensor and the scanning electron micrograph of a suspended CNT-attached $T$-type nanosensor.

Figure 2

Resistance-temperature coefficient of nanosensor ($t=27.5\mathrm{nm}$, $w=332\mathrm{nm}$, $l_h=5.37\mu \mathrm{m}$).

Figure 3

Thermal conductivity of nanosensor ($t=27.5\mathrm{nm}$, $w=332\mathrm{nm}$, $l_h=5.37\mu \mathrm{m}$).

Figure 4

Temperature rise versus heating rate measured in a vacuum.

Figure 5

Thermal conductivity of a single carbon nanotube at different diameters [(a) $d_o=9.8\mathrm{nm}$, $d_i=5.1\mathrm{nm}$, $l_f=3.70\mu \mathrm{m}$; (b) $d_o=16.1\mathrm{nm}$, $d_i=4.9\mathrm{nm}$, $l_f=1.89\mu \mathrm{m}$; (c) $d_o=28.2\mathrm{nm}$, $d_i=4.2\mathrm{nm}$, $l_f=3.60\mu \mathrm{m}$].

Figure 6

Thermal conductivity of a single carbon nanotube at 100–320 K.