Electronic properties of Gd@C82 metallofullerene peapods:: (Gd @ C82)n@SWNTs

Electronic properties of Gd@C-82 metallofullerene peapods, (Gd@C-82), @SWNTs, were investigated by electron energy-loss spectroscopy (EELS), scanning tunneling microscopy and spectroscopy (STM/STS), and field-effect transistor (FET) transport measurements. The results indicate that the electronic structure of Gd@C-82 metallofullerene peapods is completely different from that of intact single-walled nanotubes (SWNTs). For example, Gd@C-82-peapod-FETs show ambipolar behavior which is not observed in the empty SWNT-FETs under our experimental conditions. Furthermore, in semiconducting nanotubes the band gap can be varied from similar to0.5 to similar to0.1 eV using inserted Gd@C-82 endohedral metallofullerenes with a spatial periodicity of 1.1 to 8.0 nm, depending on the density of the fullerenes. The present findings suggest that metallofullerene peapods may point the way toward novel electronic devices.