Microstructure and electron emission properties of films prepared from single-wall and multi-wall nanotubes containing powders

The microstructure and field emission properties of films prepared from com mercial powders of single-wall and multi-wall carbon nanotube films were in vestigated. In addition to nanotubes, these materials contained amorphous a nd crystalline carbon phases, and the single-wall powder also contained nan o-particles of the Fe-Co catalysts. The turn-on fields were measured to be 2.3 V mum(-1) for films prepared with the material containing single-wall n anotubes and 2.6 V mum(-1) for those with multi-wall nanotubes. Long-term s tability of emission current for these films was also investigated and corr elated to their microstructure. Single-wall material showed a decrease in e mission current that extended over several days and that was related to per manent degradation of emission sites. Emission current From the multi-wall material stabilized after an initial increase.