Field emission characteristics of carbon nanotubes according to the high   energy ion irradiation
  The field emission properties of ion irradiated multiwalled carbon nanotubes (MWCNTs) and doublewalled carbon nanotubes (DWCNTs) have been studied. The carbon nanotubes synthesized by a chemical vapor deposition method were irradiated by high energy (90 MeV) Au ions with different ion fluence from 4x1011 to 1x1013 ions/cm2 . After ion irradiation, the field emission properties of MWCNTs and DWCNTs were greatly influenced. The change in the emission characteristics is due to structural defects caused by the high energy ion irradiation. The emission characteristic of MWCNTs was improved and turn-on field decreased from 5.43 to 3.10 V/m by ion irradiation. Noticeable improvement in emission characteristics of MWCNTs was observed at a fluence of 1x 10 13 ions/cm2. The emission characteristics of DWCNTs deteriorated and the turn-on field was increased from 2.44 to 7.76 V/m. This results show the distinctly different behavior of ion irradiated MWCNTs and DWCNTs. 
P.M. Koinkar, A. Kumar, D.K. Avasthi, M.A. More, Ri-ichi Murakami
cond-mat.mtrl-sci