Field penetration induced charge redistribution effects on the field emission properties of carbon nanotubes : a first-principle study

doi:10.1016/j.apsusc.2004.01.004

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題名:	Field penetration induced charge redistribution effects on the field emission properties of carbon nanotubes : a first-principle study
作者:	Chen, Chun-Wei;Lee, Ming-hsien;Clark, S.-J.
貢獻者:	淡江大學物理學系
關鍵詞:	Field emission;Carbon nanotubes;First-principle;Workfunction Field emission;Carbon nanotubes;First-principle;Workfunction
日期:	2004-04-30
上傳時間:	2009-12-31 10:45:49 (UTC+8)
出版者:	Netherlands: Elsevier
摘要:	The effect of field penetration induced charge redistribution on the field emission properties of carbon nanotubes (CNTs) have been studied by the first-principle calculations. It is found that the carbon nanotube becomes polarized under external electric field leading to a charge redistribution. The resulting band bending induced by field penetration into the nanotube tip surface can further reduce the effective workfunction of the carbon nanotubes. The magnitude of the redistributed charge ΔQ is found to be nearly linear to the applied external field strength. In addition, we found that the capped (9, 0) zigzag nanotube demonstrates better field emission properties than the capped (5, 5) armchair nanotube due to the fact that the charge redistribution of π electrons along the zigzag-like tube axis is easier than for the armchair-like tube. The density of states (DOS) of the capped region of the nanotube is found to be enhanced with a value 30% higher than that of the sidewall part for the capped (5, 5) nanotube and 40% for the capped (9, 0) nanotube under an electric field of 0.33 V/Å. Such enhancements of the DOS at the carbon nanotube tip show that electrons near the Fermi level will emit more easily due to the change of the surface band structure resulting from the field penetration in a high field. The effect of field penetration induced charge redistribution on the field emission properties of carbon nanotubes (CNTs) have been studied by the first-principle calculations. It is found that the carbon nanotube becomes polarized under external electric field leading to a charge redistribution. The resulting band bending induced by field penetration into the nanotube tip surface can further reduce the effective workfunction of the carbon nanotubes. The magnitude of the redistributed charge ΔQ is found to be nearly linear to the applied external field strength. In addition, we found that the capped (9, 0) zigzag nanotube demonstrates better field emission properties than the capped (5, 5) armchair nanotube due to the fact that the charge redistribution of π electrons along the zigzag-like tube axis is easier than for the armchair-like tube. The density of states (DOS) of the capped region of the nanotube is found to be enhanced with a value 30% higher than that of the sidewall part for the capped (5, 5) nanotube and 40% for the capped (9, 0) nanotube under an electric field of 0.33 V/Å. Such enhancements of the DOS at the carbon nanotube tip show that electrons near the Fermi level will emit more easily due to the change of the surface band structure resulting from the field penetration in a high field.
關聯:	Applied Surface Science 228(1-4), pp.143-150
DOI:	10.1016/j.apsusc.2004.01.004
顯示於類別:	[物理學系暨研究所] 期刊論文

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