16. Carbon Nanotube-Based Nanoelectronics

Carbon nanotubes serve as ideal one-dimensional materials for nanoscale electronic circuitry, not only because of their small size but also due to their overall exceptional properties, providing the necessary mechanical and chemical stability to the devices. Amongst the three main processes developed for CNT growth, namely arc discharge, laser ablation and chemical vapor deposition, the last one stands out prominently for its adaptability to nanoelectronics manufacturing. A noteworthy feature of fabrication of CNT devices is that the process is doping-free. Instead of doping, the polarity of the FETs is determined by the metals used as contacting electrodes. By appropriate choice of metals, P-channel, N-channel and complementary symmetry CNT FETs are realized. Elimination of the doping requirement for fabrication of CNT devices makes them invulnerable to dopant-related fluctuations. Semiconducting CNTs form the basis of transistor circuits whereas metallic CNTs are used as interconnects. Self-aligned process for large-scale fabrication of P-channel, N-channel and complementary CNT configurations paves the way towards adoption of CNT technology for bulk production.