Field emission properties of defect-removed single-walled carbon nanotubes

Defect-free single-walled nanotubes (SWNTs) were prepared by chemical reaction from normal SWNTs, and field emission and dispersion properties of both were compared. The field emission currents of defect-removed SWNTs are measured as a function of the number of defects, i.e., reaction time with methyl acrylate. As the defects are removed from surface of nanotubes, the SWNTs become entangled and more separated between themselves, thus the separated SWNTs have the higher aspect-ratio than the pristine SWNTs. Consequently the SWNTs having the small number of defects show the higher field emission currents. It was also shown in the UV absorption spectra of the samples in ethanol in the field emission experiment, that the more defect-removed SWNTs are better dispersed in the solvent.