Self-assembly of high-performance multi-tube carbon nanotube field-effect transistors by ac dielectrophoresis

A physical self-assembly process based on ac-dielectro-phoretic deposition of single-walled carbon nanotubes between metallic electrodes and subsequent gate-voltage controlled elimination of the metallic nanotubes is reported that allows fabrication of multi-tube carbon nanotube field-effect transistors with electrical ON/OFF ratios up to more than seven orders of magnitude. Before deposition, the carbon nanotubes were suspended by means of single-stranded DNA or sodium-taurodeoxycholate. Exposure of the devices to ethanol vapor revealed a higher sensitivity for devices made from DNA-suspended carbon nanotubes.