Fabrication of n-type nanotube transistors with large-work-function electrodes

The authors found experimentally that carbon nanotube field-effect transistors (CNFETs) could exhibit n-type characteristics even though their electrodes consist of a large-work-function metal such as Co. To explain their result, which is contrary to the general belief that CNFETs with large-work-function electrodes always lead to p-type characteristics, ab initio electronic structure calculation for the metal-carbon nanotube junction was performed, which showed that the Fermi level alignment at the junction could sensitively depend on microscopic structures of the metal-carbon nanotube junction. This suggests that deposition method of electrodes as well as the metal type could be utilized to obtain n-type CNFETs. (c) 2007 American Institute of Physics.