Robust Transition Metal Contacts for Aligned Carbon Nanotubes

Aligned carbon nanotubes (A-CNTs) are emerging as one of the most promising materials for next-generation nanoelectronics. However, achieving reliable ohmic contacts between A-CNTs and metals remains a critical challenge. In this study, we employ rapid thermal annealing (RTA) to facilitate the formation of transition metal carbides at the metal-CNT interface, significantly reducing contact resistance and enhancing stability. Using the transmission line method (TLM), we demonstrate that RTA reduces the contact resistance at the Ti/A-CNT interface from 112.26 kΩ·μm to 1.57 kΩ·μm and at the Ni/A-CNT interface from 81.72 kΩ·μm to 1.17 kΩ·μm, representing a reduction of over an order of magnitude. Moreover, the Schottky barrier heights (SBHs) for both the Ti/A-CNT and Ni/A-CNT interfaces decreases by approximately 50% after annealing. A comparative analysis with Pd/A-CNT contacts shows that Ti and Ni contacts exhibit superior reliability under harsh conditions. This work provides a viable solution for improving the electrical performance and reliability of CNT-based devices, offering a pathway toward the development of future CMOS technologies.