Nanotube transistors are valuable for future nanocomputer design. They exploit the fact that carbon nanotubes are ready-made wires that can conduct, semiconduct or insulate. In the latest development from IBM, nanotube transistor architecture has been reconfigured such that nanotubes acting as the conducting channel between the transistor source and drain are not exposed to air (top-gate configuration), and so that neighbouring transistors can be addressed individually.
By experimenting with different device structures, researchers have been able to achieve the highest transconductance (a measure of the current-carrying capability) of any carbon nanotube transistor to date. High transconductance means that transistors can run faster, leading to more powerful integrated circuits. Furthermore, the researchers discovered that the carbon nanotube transistors produced more than twice the transconductance per unit width of top-performing silicon transistor prototypes. AIP
Further reading
S J Wind et al. 2002 Appl. Phys. Lett. 80 3817.