基于PECVD的碳纳米管生长及其场致发射特性

Synthesis and Emission Properties of Carbon Nanotubes Using Plasma Enhanced Chemical Vapor Deposition

采用等离子体增强化学气相沉积方法,以Ni作为催化剂实现碳纳米管阵列定区域单根分立生长。扫描电子显微镜分析结果表面,碳纳米管呈现笔直生长,生长速率大于500 nm/min,长度和直径比较均匀,且具有高度的定向性,排列整齐并垂直于基底。透射电子显微镜分析结果显示,生长的碳纳米管表现典型的多壁碳纳米管结构特征,并且晶格缺陷非常少。在高真空系统中对生长的碳纳米管阵列进行场致发射特性测试,结果表明生长的碳纳米管发射阵列具有很好的场致发射特性,最大电流密度大于1 A/cm2。老炼试验显示生长的碳纳米管阵列场致发射特性具有良好的稳定性。紫外光子谱线法测试结果表明,生长的碳纳米管的功函数为4.96 eV,由此计算出碳纳米管阵列相对应的场增强因子大于1100。本文的研究结果提供了一种简单的可实现大面积和规模化的基于碳纳米管场致发射阴极的制备途径。

A method to grow single carbon nanotube （CNT） arrays at predetermined sites using plasma enhanced chemical vapor deposition with Ni catalyst is reported. The images of high resolution field-emitter scanning electron microscope show that CNTs are freestanding, well-aligned, and vertically-oriented. Furthermore, these CNTs have a uniform length and diameter. The growth rate of CNTs is more than 500 nm/min. Transmission electron microscope images of CNTs indicate typical multi-walled CNTs lattice structure with few defects. Measurements results show that a highly stable field emission current density of more than 1 A/cm2 at an electric field of 9.9 V/μm is obtained. The field factor of the grown CNTs is more than 1100, whose work function is 4.96 eV measured by ultraviolet photon spectrum. Our experiments indicate a promising fabrication route for large area CNT-based field emitters with high performance.