Electron properties of a microcolumn with a CNT tip

We investigated a possibility of the CNT tips as an electron emitter tip of a miniaturized microcolumn. For the purpose, we analyzed potential distribution, field distribution and electron beam properties of the conventional tip, single-walled nanotube (SWNT) and double-walled nanotube (DWNT). From the result, we made certain that the nanotube emitters have advantages in small beam divergence angle and beam current enhancement. Especially, the SWNT has the largest field strength at the tip apex among the three tips, thus it can emit enough electron current even at a low extract bias voltage. On the other hand, the DWNT has the smallest electron beam divergence angle. It means that the tip has the largest depth of focus among the three investigated tips.