一种带栅极碳纳米管阴极阵列的场发射性能研究

Simulation of Field Emission Characteristics of Gated Carbon Nanotubes Array

研究碳纳米管与衬底之间的电学接触和器件结构尺寸的优化设计是提高碳纳米管冷阴极器件场发射特性的关键之一。本文利用镜像电荷法计算了一种背栅极碳纳米管阴极阵列的表面电场,给出碳纳米管顶端表面电场与接触电阻的关系,分析了接触电阻与栅极偏压对场发射电流、发射体顶端表面电场的影响。另外,还探究了最佳栅孔单元分布密度。结果表明,接触电阻大幅度降低了碳纳米管顶端表面电场与发射电流,当接触电阻高于1 MΨ时,器件对阳极驱动电压的要求更高,而栅极偏压的调制,能够有效地降低阳极驱动电压,最佳栅孔单元分布距离为约两倍的碳纳米管高度。

The field emission of the gated carbon nanotubes （CNTs） array was modeled with the image charge of floated spheres in the triode configuration, and analytically calculated by evaluating the potential distribution and realistic electric field at the hemispherical ends of CNTs, which were assumed to stand vertically on the cathode with an approxi-mated contact resistance. The influence of the contact resistance on the field emission current and electric field at the CNT apex was investigated with F-N formula. The calculated results show that the contact resistance significantly reduces the emission current of the gated CNTs array and the realistic field at the CNT apex. A contact resistance higher than 1 MΩ reduces the emission current almost to zero. We suggest that an optimized＂ gate-hole＂ distance may improve the field emission properties of the gated CNTs＇ army. The calculated results may be of some technological interest.