Observation of Joule heating in multi-walled carbon nanotubes by electron thermal Microscopy

We report Joule heating in multi-walled carbon nanotubes under voltage bias by using an electron thermal imaging technique [1]. Briefly, the temperature profile is obtained by observing the solid to liquid phase transitions of indium islands sub-100nm in diameter, thermally deposited on the back side of an electron transparent dielectric membrane. The high spatial-resolution maps thus obtained demonstrate that in the high-voltage-bias regime the thermal dissipation occurs not at the electrode contacts but along the entire length of the nanotube as predicted in [2]. The low temperatures involved ($<$200~C) extend previous results [3] into a new temperature regime. The implications of these results when combined with other observations in the literature will be discussed. \\[4pt] [1] Brintlinger et al, Nano Lett., \textbf{8}, 582 (2008)\\[0pt] [2] Yao et al, Phys. Rev. Lett., \textbf{84}, 2941 (2000)\\[0pt] [3] Begtrup et al, Phys. Rev. Lett. \textbf{99}, 155901 (2007)