空間分佈效應對垂直排列之奈米碳管之場發射效應研究
Date Issued
2003
Date
2003
Author(s)
DOI
912216E002039
Abstract
Field penetration induced charge redistribution
effects on the field emission properties of carbon
nanotubes have been studied by the
first-principles calculations. It is found that the
carbon nanotube is polarized under external
electric field leading to charge redistribution.
The resulting band bending induced by field
penetration into the nanotube tip surface can
further reduce the effective workfunction of
carbon nanotubes (CNTs). The magnitude of
redistributed charge ∆Q is found nearly linear to
the applied external field strengths. In addition,
we found that capped (9,0) zigzag nanotube
demonstrates better field emission properties
than the capped (5,5) nanotube due to that the
charge redistribution of π electrons along the
zigzag-like tube axis is easier than the
armchair-like tube. The density of states (DOS)
of the capped region of the nanotube is found to
be enhanced with a value of 30 % higher than
that of the sidewall part for the capped (5,5)
nanotube and 40% for the capped (9,0) nanotube
under the electric field of 0.33 V/A. Such
enhancements of DOS at the carbon nanotube tip
show that electrons near the Fermi level will
emit more easily due to the change of surface
band structure resulted from the field penetration in a high field.
Publisher
臺北市：國立臺灣大學材料科學與工程學研究所
Type
report
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