ELECTRONIC-PROPERTIES OF CARBON NANOTUBE

The electronic properties of purified carbon nanotube (multicylinder structure with an outer diameter of almost-equal-to 20 nm and a length of almost-equal-to 10 mum) was first examined based on the electron spin resonance (ESR) spectroscopy. By the Raman scattering measurement, only one peak at 1581 cm-1 similar to that of graphite was found. The purified nanotube was almost ESR silent as well as the K- and the I2-doped samples. This indicates that the purified nanotube examined in the present study is a 'clean' semiconductor almost without magnetic impurity and is doping inactive.