Measurements of electronic transport properties of single-walled carbon nanotubes encapsulating alkali-metals and C60 fullerenes via plasma ion irradiation

Abstract

We report on the measurements of the electronic transport properties of Cs-encapsulated single-walled carbon nanotubes (SWNTs), Li-encapsulated SWNTs, and C60-encapsulated SWNTs synthesized by plasma ion irradiation method. After fabricating field-effect transistor (FET) configurations using pristine and plasma-ion-irradiated SWNTs, the electronic transport properties of these devices are investigated in vacuum at room temperature. As a result, C60-encapsulated SWNTs give rise to a p-type semiconducting property as pristine SWNTs do. On the other hand, it is clearly observed that Cs-encapsulated SWNTs exhibit n-type transport behavior. Moreover, Li-encapsulated SWNTs show an ambipolar transport property with both n-type and p-type characteristics. Thus, the electronic properties of SWNTs are found to be successfully controlled by plasma ion irradiation. ©2005 The Japan Society of Applied Physics.