Exploring the limits of Carbon Nanotunde Transistors
CNS researchers have developed a new technique to examine the ultimate performance limits of carbon nanotube devices. An atomic force microscope (AFM) tip was used to make local electrical contact to a carbon nanotube only a few ten billionths of a meter in diameter (~10 nm). This movable contact was used to examine the electrical properties of nanotube device as the function of their length. For short semiconducting nanotube transistor devices, the transistor performance that was observed was within a factor of three of the fundamental limit that can be achieved with the electrons traveling ballistically through the nanotube without any scattering, unlike the diffusive motion that describes electron transport in conventional semiconductor devices. In metallic carbon nanotubes, the local AFM probe was used to measure the scattering of the electrons from the vibrations of the carbon ions. This scattering limits the ultimate current-carrying capacity of carbon nanotubes. Metallic carbon nanotubes have substantial potential for applications as electrical interconnects (wiring) in nanoscale applications that require very high current levels.
A schematic drawing illustrating how an atomic force microscope tip can be used to contact a carbon nanotube and used to measure the electrical behavior of the nanotube as the tip moves further or closer to the fixed electrical contact. At the shortest length measured, the nanotube behavior was within a factor of three of the ideal ballistic limit .
[CNS Investigators: P. L. McEuen, P. W. Brouwer and T. A. Arias]
For additional information see:
- Y. Yaish, et al. "Electrical Nanoprobing of Semiconducting Carbon Nanotubes Using an Atomic Force Microscope," Phys. Rev. Lett. 92 , 046401 (2004)
- Ji-Yong Park , et al. , "Electron-Phonon Scattering in Metallic Single-Walled Carbon Nanotubes Nano Lett. 4, 517 (2004)