Carbon nanotube/nanodiamond structures: An innovative concept for stable and ready-to-start electron emitters

Efficient and robust cold cathodes have been assembled using as emitting material mats of single wall carbon nanotubes (SWCNTs) coated with nanodiamonds. The preparation of the hybrid nanotube/nanodiamond structures by chemical vapor deposition is a route suitable to be scaled up and adapted to the electronic industry requirements. Turn-on field of 1.7 V/mu m and emission current density J of 6 mA/cm(2) at applied field E of 6.2 V/mu m were measured. The field emission properties of SWCNT coated with nanodiamond are very attractive in terms of reproducibility, current stability under medium vacuum and lack of arcing. Moreover, the diamond coating acts against the adsorption of chemical species, making it possible to avoid the outgassing procedures usually needed for current stabilization and allowing to reduce the time response for electron sources assembled with these hybrid materials.