N -type carbon nanotube by alkaline-earth metal Sr doping

Abstract

Alkaline-earth metal, Sr, was doped on multiwalled carbon nanotubes (MWNTs) by vapor phase reaction method. The tunneling electron microscopy, energy dispersive x ray, and Raman spectroscopy were studied for verifying the Sr doping on MWNT. The temperature-dependent resistivity [ρ(T)] and thermoelectric power [S(T)] were also performed for both pristine MWNT and Sr-doped MWNT (Sr-MWNT). ρ(T) of Sr-MWNT did not significantly change compared to pristine MWNT. However, S(T) of Sr-MWNT considerably changes, i.e., it shows n-type behavior in contrast to pristine MWNT.