多層カーボンナノチューブヘのホウ素ドープ

抄録

Boron doping to carbon nanotube was carried out on pressed samples of multiwall carbon nanotube (MWCNT) prepared by a CVD method. As-prepared sample was pressed as disks of 20mm in diameter with an apparent density of 0.72g·cm³. The disks were heat-treated at 3000°C to remove iron impurity. From the heat-treated disks, samples with sizes about 1.5×1.5×6mm³ were cut. Boron doping was carried out by heating the sample to 2300°C in a crucible made of a commercially available artificial graphite contained 10wt% born. We employed lhr heat treatment as a unit of doping treatment, and carried out doing of 1 to 3 times for the samples. Boron concentrations of the boron-doped samples were determined by an EPMA technique. Structural characterization of the doped samples was made with X-ray diffraction and Raman spectroscopy measurements and SEM observation. The characterization revealed that almost of born doped samples were consisted of MWCNT's contained boron, small thin boron-contained crystallites with graphite structure and B₄C small crystals. Effect of boron doping was examined by the measurements of electrical resistivity at liquid nitrogen and room temperatures and magnetic susceptibility at 5 and 300K as a function of boron concentration for the boron-doped samples.