Modeling of kink-shaped carbon-nanotube Schottky diode with gate bias modulation

A model is proposed for the recent gate voltage V-G modulation experiment of a kink-shaped carbon nanotube (NT) Schottky diode [Z. Yao, H. Postma, L. Balents, and C. Dekker, Nature (London) 402, 273 (1999)]. Since larger V-G increases both the forward and the reverse turn-on voltages of the diode, we show that: (1) the rectification must occur at the kink where the metallic and the semiconducting NTs meet, and not at the electrode contact, and (2) the semiconducting NT must be n type. The turn-on voltages are derived analytically as a function of V-G considering the electrode contact contribution and a good agreement is obtained with the experimental data. (C) 2002 American Institute of Physics.