A field effect transistor fabricated with metallic single-walled carbon nanotubes

We report novel transport properties of the individual single-walled carbon nanotube (SWNT) field effect transistors (FETs) decorated with the protein (streptavidin)-coated nanoparticles. Upon adsorption of the protein-coated nanoparticles at the metal-nanotube contact, the metallic SWNT devices abruptly exhibit a p -type semiconducting behavior. In the case of semiconducting SWNT devices, the adsorptions of protein-coated nanoparticles make the gating more effective, resulting in a far suppressed off-state leakage current as well as an enhanced on-state p -channel current. Through the ab initio electronic structure calculations, it is suggested that such an apparent metal-semiconductor transition may be due to the intervening charged species in the contact area, originated from the surface of the proteins. Noting the separation of the semiconducting nanotubes from metallic ones would be a formidable task; we suggest that the device concept here could be another breakthrough for the nanotube-based electronic devices, in which the nanotubes are not necessarily semi-conducting.close1