Field-emission performance and structural change mechanism of multiwalled carbon nanotubes by oxygen plasma treatment

• Field-emission characteristics of MWCNTs using O2 treatment were studied.
• The analysis of Seppen-Katamuki chart was used.
• The O2 plasma could remove the entangled MWCNTs by etching the tip of MWCNTs
• The O2–treated MWCNTs showed the great enhancement in field-emission properties.

Multiwalled carbon nanotube (MWCNT) arrays were synthesized by thermal chemical vapor deposition. To investigate the effect of O2 plasma on the properties of the field-emission, MWCNT arrays were exposed to O2 plasma. Field-emission properties, such as emission current and stability, were greatly improved after the O2 plasma treatment. The O2 plasma could remove the entangled thin MWCNTs and etch the tips of MWCNTs, leading to reduced density and sharpened tips. The analytical estimation extracted from the Fowler–Nordheim plot supports the observation of sharpening the tips of nanotubes with little change of the work function of nanotubes.