Double-wall carbon nanotube field-effect transistors: Ambipolar transport characteristics

Double-wall carbon nanotubes (DWNTs) have been used as channels of field-effect transistors (FETs) to obtain information on their transport characteristics. DWNTs-FETs show metallic or semiconducting behavior depending on the tube diameters. All the semiconducting DWNTs have exhibited both p- and n-type characteristics, the so-called ambipolar behavior which is absent in normal SWNTs-FETs. Comparisons between the subthreshold swing (S) factor of DWNTs and that of SWNTs indicate that DWNTs are better FET channels than SWNTs.