摘要
本文通过分析碳纳米管的电荷分布规律,巧妙地将处于外电场中且端口封闭的金属性碳纳米管等效成电荷非均匀分布的球面,获得了包括端部球面电荷、管壁电荷与镜像电荷共同作用的场增强因子为β=1.14h/R+2.62。结果表明:场增强因子是碳纳米管长径比h/R的线性函数,并与电荷分布密切相关。在此基础上,研究发现35%的管壁电荷对碳纳米管电子发射的场增强因子贡献约为9.7%,但仍远大于镜像电荷的影响。根据模型中电荷非均匀分布导致碳纳米管各处局域电场大幅度变化,解释了仅在球面的一定区域才大量发射电子且发射电流密度不均匀的实验现象。
By introducing the spherical surface charge with non-uniform distribution for a closed metallic carbon nanotube located in the applied electric field E0, we obtained the field enhancement factorβ = 1.14h/R ＋ 2.62. The calculated result shows thatβ is a linear function of aspect ratio h/R of carbon nanotube and related to charge distribution. The contribution of the tube-wall charges toβ is about 9.7 %, but it is much larger than that of image charges. Furthermore, it is the remarkable change of the local field caused by the charge non-uniform distribution that can explain the fact that the electrons emit only in the limited region of sphere surface.
出处
《人工晶体学报》
EI
CAS
CSCD
北大核心
2008年第2期407-410,426,共5页
Journal of Synthetic Crystals
基金
西北工业大学研究生创业种子基金(No.Z200662Z200762)
关键词
碳纳米管
电荷分布
场增强因子
场发射
carbon nanotube
charge distribution
field enhancement factor
field emission
