C60 Peapods Research Articles

Electronic properties of intercalated single-wall carbon nanotubes and C60 peapods

This paper reviews recent investigations of the electronic structure and the optical properties of intercalated single-wall carbon nanotubes (SWCNTs) and C60 filled SWCNTs (peapods) using electron energy-loss spectroscopy (EELS) in transmission as a probe. The results from these one-dimensional nanostructures are compared to C60 fullerides and intercalated graphite, which are well understood prototypes of carbon-based intercalation compounds. In detail, the structural changes were analysed by electron diffraction and the doping level and the matrix element weighted unoccupied density of states (DOS) by an analysis of the C 1s core-level excitations. Regarding the optical properties, the intercalation gives rise to a charge transfer to the peapods (SWCNTs) which leads to the formation of a free charge carrier plasmon in the loss function which is analysed within the framework of an effective Drude–Lorentz model.

Determination of the filling factor of C60 peapods by electron energy-loss spectroscopy in transmission

We have studied electron diffracion and core-level excitations of C 60 molecules encapsulated in single-wall carbon hanotubes, so-called, peapods, by electron energy-loss spectroscopy in transmission. The overall shape of the response of the single wall nanotube and the peapods is very similar but with distinct differences in the fine structure. The filling factor of C 60 peapods can be estimated with our volume-sensitive probe.

Ambipolar field-effect transistor behavior of Gd@C82 metallofullerene peapods

Transport properties of C60 fullerene peapods and Gd@C82 metallofullerene peapods are investigated by using the field effect in a gated structure. The results show that C60 peapods exhibit unipolar p-type characteristics, whereas Gd@C82 peapods show ambipolar both p- and n-type characteristics. This difference in transport behavior can be explained in terms of a bandgap narrowing of the peapods. One of the important findings is that tunable electronic properties of peapods are achieved by using the different types of encapsulated fullerene molecules.