Electronic measurements of alkali metal-encapsulated single-walled carbon nanotubes produced by plasma ion irradiation

We report detailed experimental results of the electronic transport properties of Cs-encapsulatcd single-walled carbon nanotubes (SWNTs) produced via plasma ion irradiation method. After fabricating field-effect transistor (FET) configuration using pristine and alkali metal ion irradiated SWNTs as channel, the electronic transport properties of these devices are investigated. As a result, pristine semiconducting SWNTs show p-type transport properties. On the other hand, it is clearly observed that Cs-encapsulated semiconducting SWNTs have n-type transport behavior. This phenomenon can be explained in terms of charge transfer from Cs atoms in SWNTs. Moreover, ambipolar property is obtained by measuring Li-encapsulated SWNTs FET.