碳纳米管接触电阻的研究进展

与金属之间过高的接触电阻是影响碳纳米管在微纳电子器件中应用的关键因素之一，本文从形成机理和改善方法两个方面综述了近年来碳纳米管接触电阻的研究进展。介绍了利用第一性原理对碳纳米管与金属界面电子输运性能的理论研究，以及金属功函数对界面势垒调试作用的实验研究。研究表明金属与碳纳米管之间具有较弱的杂化作用和较长的接触长度时，接触电阻较小；金属与碳纳米管功函数越接近，势垒高度越低。阐述了超声焊接技术、高温退火法、金属沉积法、局部焦耳热法等常用降低碳纳米管接触电阻方法的作用机理，并分析了这些方法对器件性能的改善作用。其中局部焦耳热法操作简单、易于自动化、对器件损害小、成本低，是目前比较理想的降低碳纳米管接触电阻的方法。

Progress on Research of Contact Resistance of Carbon Nanotubes

The high contact resistance of carbon nanotubes ( CNTs) with metal is one key factor that retards the application of CNTs in micro-and nano-electronics devices. This paper reviews recent research progress on the contact resistance of CNTs from two aspects, they are the formation and improvement of the CNT’ s contact resistance. Theoretical studies of the contact resistance of CNTs using the first principles and experimental investigations into the effect of metal work function on the interface barrier were introduced. Results show that the contact resistance is low when there is a weak hybrid effect and large contact length between the metal and CNTs, and the closer the work function of the metal to that of the CNTs, the lower the barrier height. The commonly used methods for improving the contact resistance of CNTs, including ultrasonic nanowelding, high temperature annealing, metal deposition, and local Joule heating were presented, and the improvement of device performance using these methods was analysed. Among these methods, local Joule heat-ing is more ideal at present time since it is with the advantages of simple operation, high degree of automation, less device damage, and low cost.