Abstract: Large-scaled highly oriented carbon nanotube films on Si substrate with Ni as a catalyst were synthesized by hot-filament-enhanced CVD and field-emission properties of the films were studied. It has been discovered that there is a knee-point E_s on Fowler-Nordheim curves of the nanotube films, the slope of F-N curve in the low field region is much higher than that in the high field region. The field-enhancement factor β is proportional to the distance d between the anode and the cathode, and E_s is an inverse measure of the distance d. Both of them can be phenomenally interpreted by the two-region field-emission model. The possible mechanisms for the saturation of emitter current on high field region have been discussed.

Key words: well-aligned carbon nanotube film, field emission, fowler-nordheim equation, field amplification factorβ

摘要： 利用热丝增强化学气相沉积法，在镀Ni的Si基片上成功地生长大面积取向碳纳米管膜，并研究了其场发射性质。研究表明，碳纳米管膜的场发射Fowler-Nordheim曲线上存在一转折点E_s(“饱和”场强)，低场区域(E＜E_s)的F-N曲线斜率明显高于高场(E＞E_s)区域。实验证实，低场区域的场放大系数β与极间距d 成正比，E_s与极间距d 成反比，它们可用双区域场模型唯像地解释。讨论了高场区域场发射电流“饱和”(变化趋缓)的可能机制。

关键词: 取向碳纳米管膜, 场发射, Fowler-Nordheim公式, 场放大系数β