In-situ studies of electron field emission of single carbon nanotubes inside the TEM

Electron field emission characteristics of individual multi-walled carbon nanotubes (MWCNTs) were investigated in situ inside the transmission electron microscope (TEM). For a single MWCNT it was found that while field-emission can hardly occur from the side of the nanotube, a curved nanotube may result in finite side emission and the best emission geometry is the top emission geometry. Current-voltage (I-V) measurements made at different vacuum conditions and voltage sweeps emphasize the importance of the adsorbates on the electron field emission of MWCNTs. For a contaminated MWCNT, although the field emission current was reduced, the stability of its emission was improved. A current of up to several tens of mu A was observed for a single MWCNT, but it was found that long time emission usually results in drastic structure damage that may lead to sudden emission failure. (c) 2004 Elsevier Ltd. All rights reserved.Chemistry, PhysicalMaterials Science, MultidisciplinarySCI(E)EI37ARTICLE51026-10314