Current-induced cleaning of adsorbates from suspended single-walled carbon nanotube diodes

Due to their large surface-to-volume ratio compared to that of a bulk semiconductor, carbon nanotubes are very sensitive to their environment. Their properties can be dramatically changed by simple exposure to air. Here, we show that the electronic and optical properties of p-n diodes fabricated with single-walled carbon nanotubes degrade over time with exposure to ambient conditions, mainly due to adsorption onto the tube's suspended part, which creates band-gap states. Most importantly, we demonstrate a simple technique-current annealing-that can thermally reverse such degradation.