Blackbody radiation from resistively heated multiwalled carbon nanotubes during field emission

We report the observation of blackbody radiation from aligned multiwalled carbon nanotubes undergoing field emission. The light intensity correlates with fluctuations in the emission current. The onset of light emission occurs at an emission current of $\text{1\hspace{0.17em}}{\mathrm{mA/cm}}^2$ and corresponds to a temperature on the order of 1550 K. Beyond this critical current irreversible changes occur in the nanotube film. The correlation between light intensity and emission current provides convincing evidence for Joule heating and stable operation for nanotube temperatures up to at least 2000 K and emission current densities on the order of $\text{10\hspace{0.17em}}{\mathrm{mA/cm}}^2.$