Nanometer-level temperature mapping of Joule-heated carbon nanotubes by plasmon spectroscopy

We map the temperature distribution of suspended carbon nanotubes down to the 5-nm level inside a trans-mission electron microscope, by using electron energy-loss plasmon spectroscopy. The nanotubes are Joule heated in-situ, by individually contacting them using a biasing holder. The nanotubes can withstand current densities of over 5 x 107 A/cm2 and temperatures of over 2000 K without breaking. The temperature reaches its maximum around the nanoprobe contact, due to the comparatively large electrical resistance and small thermally-conductive area. The temperature remains high along the entire length of the CNTs, due to the excellent in-plane thermal conductivity (up to 2800 W/m/K) of the graphitic lattice. These results verify the expected robustness of these structures and confirm them as ideal candidates for applications as interconnects under extremely high current densities and temperatures.