The screening effect on field enhancement factor of the finite-length small radius single-walled carbon nanotubes

Abstract

The screening effects on the field enhancement factors of (3,3) and (5,0) finite length single-walled carbon nanotubes (SWCNTs) with respect to different kinds of tube terminations, either capped or H-terminated, are examined using first-principles calculations. Results show that for capped SWCNTs, the field enhancement factors of the (3,3) tube are slightly greater than those of (5,0) ones, while for H-terminated tubes exhibit the opposite effect. The effects of different endings on the SWCNT work functions are also investigated. Calculations show that for the capped SWCNTs, the work functions of (3,3) tubes are larger than those of (5,0) tubes, whereas for the H-terminated cases, the work functions of (3,3) tubes are smaller than those of the (5,0) tubes. Moreover, a saturated behavior of enhancement factors β versus the length of tubes is observed. Finally, the field enhancement factors of fixed length tubes can be enhanced to eventually achieve a convergent tendency as their tube-tube distance increases.