High performance field-effect transistors made of a multiwall CNx/C nanotube intramolecular junction

Field-effect transistors (FETs) based on an individual CNx/C nanotube (NT) were fabricated by focus ion-beam technology. The nanotube transistors exhibited n-type semiconductor characteristics, and the conductance of nanotube FETs can be modulated more than four orders of magnitude at room temperature. The electron mobility of a CNx/C NT FET estimated from its transconductance was as high as 3.84×103 cm2/V s. The n-type gate modulation could be explained as due the effect of bending of the valence band in the Schottky-barrier junction.