Field emission properties of cobalt/multiwalled carbon nanotube composite films fabricated by electrodeposition

Carbon nanotubes (CNT) are promising for use as field emitters. CNT field emitters in which CNTs are attached to a cathode by a metal are highly suitable structures for CNT field emitters. In this study, Co/CNT composite films were fabricated by composite plating for use as field emitters. Four types of multiwalled CNTs (MWCNTs) with different sizes were used as CNT field emitters. The microstructures, electrical conductivity, and field emission properties of the composite films were evaluated. Co/MWCNT composite films were fabricated with homogeneous distributions of relatively large MWCNTs, whereas small MWCNTs tended to form aggregates in the films. The Co/MWCNT composite films, which had lower electrical conductivities than pure cobalt film, exhibited clear field emission. The Co/MWCNT composite films had field emission electric fields in the range of 1.6–1.9 V μm−1 at an emission current density of 10 nA cm−2.