Electrical transport properties of double-walled carbon nanotubes (DWNTs) are modulated by encapsulating the azafullerene C59N which is synthesized via a plasma ion-irradiation method. The encapsulation of C59N molecules inside DWNTs has been confirmed by both transmission electron microscopy and Raman spectroscopy. The pristine DWNTs with outer diameter 4 - 5 nm are found to exhibit an ambipolar semiconducting behavior due to their small band gap. It is found that C60 fullerene encapsulated DWNTs exhibit a unipolar p-type semiconducting behavior. By comparison, C59N encapsulated DWNTs display an n-type semiconducting behavior. Our findings demonstrate that C59N operates as an electron donor compared with the acceptor behavior of C60, which is further clarified by photoelectron emission spectroscopy.
展开▼
