Nosho Y, Ohno Y, Kishimoto S, Mizutani T
Department of Quantum Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan.
Nanotechnology. 2006 Jul 28;17(14):3412-5. doi: 10.1088/0957-4484/17/14/011. Epub 2006 Jun 15.
We have investigated the relation between the conduction property and the work function of the contact metal in carbon nanotube field-effect transistors (NTFETs). The conduction type and the drain current are dependent on the work function. In contrast to NTFETs with Ti and Pd contact electrodes, which showed p-type conduction behaviour, devices with Mg contact electrodes showed ambipolar characteristics and most of the devices with Ca contact electrodes showed n-type conduction behaviour. This indicates that the barrier height of the metal/nanotube contact is dependent on the work function of the contact metal, which suggests that the Fermi-level pinning is weak at the interface, in contrast to conventional semiconductors such as Si and GaAs. We have also demonstrated nonlinear rectification current-voltage characteristics in a nanotube quasi-pn diode with no impurity doping, in which different contact metals with different work functions are used for the anode and the cathode.
我们研究了碳纳米管场效应晶体管（NTFETs）中接触金属的传导特性与功函数之间的关系。传导类型和漏极电流取决于功函数。与具有Ti和Pd接触电极且表现出p型传导行为的NTFETs不同，具有Mg接触电极的器件表现出双极特性，而大多数具有Ca接触电极的器件表现出n型传导行为。这表明金属/纳米管接触的势垒高度取决于接触金属的功函数，这意味着与Si和GaAs等传统半导体相比，界面处的费米能级钉扎较弱。我们还在没有杂质掺杂的纳米管准pn二极管中展示了非线性整流电流-电压特性，其中阳极和阴极使用了具有不同功函数的不同接触金属。
