Nonlinear Fowler–Nordheim plots of the field electron emission from graphitic nanocones: influence of non-uniform field enhancement factors
Nonlinear Fowler–Nordheim plots of the field electron emission from graphitic nanocones: influence of non-uniform field enhancement factors
复制标题
DOI：
10.1088/0022-3727/39/15/023
复制
发表时间：
2006-07
期刊：
影响因子：
--
通讯作者：
X. Lu;Q. Yang;C. Xiao;A. Hirose
中科院分区：
文献类型：
--
作者：
X. Lu;Q. Yang;C. Xiao;A. Hirose
采用等离子体增强热丝化学气相沉积技术，在抛光后的p型（100）硅片上合成了排列良好的石墨纳米锥。采用不同直径的阳极探针对其场电子发射特性进行了研究。在高电场作用下，场电子发射（FEE）的Fowler-Nordheim （FN）图呈现非线性。基于两类特征发射点叠加的数值计算结果与实验数据吻合较好。FN图的非线性可能归因于石墨纳米锥的非均匀场增强因子（FEF）。在低电场下，电子主要从FEF较大的纳米锥体发射，对应于FN图的斜率较小。随着电场的增大，FEF较小的纳米锥对发射电流也有贡献，导致平均FEF减小，斜率增大。如果两种发射位点的FEF差异较大，则即使在实验测试的最高电场下，FEF较小的发射位点也可能无法参与发射，FN图保持一条直线，可能是由FEF较大的发射位点决定的。
Well-aligned graphitic nanocones were synthesized on polished pristine p-type (100) silicon wafers through plasma enhanced hot filament chemical vapour deposition. The field electron emission properties were investigated using anode probes of different diameters. Non-linearity was observed in the field electron emission (FEE) Fowler–Nordheim (FN) plots at high electric field. The numerical calculations based on the superposition of two types of characteristic emission sites are consistent with the experimental data. The non-linearity in the FN plot may be attributed to the non-uniform field enhancement factor (FEF) of the graphitic nanocones. At low electric field, electrons are emitted mainly from nanocones with large FEF, corresponding to a small slope magnitude in the FN plots. With the increasing electric field, the nanocones with small FEFs also contribute to the emission current, which results in a reduced average FEF and so a larger slope magnitude. If the difference in FEFs of the two types of emission sites is large, the emission sites with smaller FEF may not be able to participate in emission even at the highest electric field tested in the experiments and the FN plot remains a straight line determined presumably by the emission sites with larger FEF.