Electrical Transport Properties of Calcium-Encapsulated Single-Walled Carbon Nanotubes Realized Using Calcium Plasma

Abstract

Calcium (Ca)-atom-encapsulated single-walled carbon nanotubes (Ca@SWNTs) are successfully formed by an ion irradiation method using Ca plasma. The electrical transport properties of Ca@SWNTs are experimentally investigated under a field-effect transistor configuration in vacuum and air. The conductance of Ca@SWNTs changes markedly compared with that of pristine SWNTs, and Ca@SWNTs exhibit air-stable unipolar n-type semiconductor behavior. This result indicates that Ca atoms are encapsulated in SWNTs and fulfill a crucial role as strong electron donors to SWNTs. A unique feature resembling a p–n junction is also observed in Ca@SWNTs.