Field emission from single-walled carbon nanotubes modified by annealing and CuCl doping.

In this article, we present a comparative study of field emission (FE) properties of the films of pristine, annealed and CuCl-filled single-walled carbon nanotubes (SWCNTs). The current-voltage dependencies and emission site distributions were measured in the diode configuration with a flat phosphor-coated anode. A significant increase of the threshold field was observed after annealing and doping of the films. It was explained by the selective oxidation of the small-diameter nanotubes confirmed by the Raman spectroscopy. The FE properties of annealed and filled SWCNTs were found to coincide with each other. At the same time, their Raman spectra differ significantly indicating the strong p-type doping induced by encapsulated CuCl. The obtained result reveals that the CuCl filling leads to significant changes in macroscopically averaged electronic properties but do not change the local work function at the apexes of emitting nanotubes, which is important for the further development of SWCNTs-based FE cathodes. [ABSTRACT FROM AUTHOR]