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

Abstract

The microstructure and field emission properties of films prepared from commercial powders of single-wall and multi-wall carbon nanotube films were investigated. In addition to nanotubes, these materials contained amorphous and crystalline carbon phases, and the single-wall powder also contained nano-particles of the Fe-Co catalysts. The turn-on fields were measured to be 2.3 V μm-1 for films prepared with the material containing single-wall nanotubes and 2.6 V μm-1 for those with multi-wall nanotubes. Long-term stability of emission current for these films was also investigated and correlated to their microstructure. Single-wall material showed a decrease in emission current that extended over several days and that was related to permanent degradation of emission sites. Emission current from the multi-wall material stabilized after an initial increase.