Materials Science and Engineering Department, Meijo University
○Mukul Kumar Okazaki Naoto Iida Atsushi Ando Yoshinori

Camphor, a well-valued material in biotechnology, is successfully brought to nanotechnology. The first report of carbon nanotubes (CNTs) from a tree product, camphor, was made by our group in 2001 [1]. Since then, we remained involved with this regenerative source of CNTs and established the conditions for growing multiwall nanotubes (MWNTs) [2,3] single-wall nanotubes (SWNTs) [4] and vertically aligned nanotubes [5] on quartz and silicon plates by a simple CVD technique. As-grown CNTs have shown appreciable field emission properties [6]. Recently, using iron-cobalt bimetallic catalyst impregnated in mesoporous zeolite powder, we have been able to grow MWNTs at a temperature as low as 550℃, whereas SWNTs could be grown at 850-900℃ [7]. The exciting new feature of our work is that, apart from the high purity (88%) of as-grown MWNTs, camphor-to-CNT production yield is 50%, which is incomparably higher than that of any other CNT precursor reported so far. Camphor-grown CNTs have relatively higher graphitization and negligible amorphous carbon. And quite recently, we have found the conditions to grow attractive CNT architecture on quartz or silicon substrate that are useful in device fabrication. The technique involves thin patterning of iron or nickel on the substrates as a growth guide, while ferrocene is used as a catalyst.

1. M. Kumar et al, Internat. Symposium on Nanocarbons, Nagano, Japan (Nov. 14-16, 2001) Extended Abstract: 244-245.
2. M. Kumar et al, Molecular Crystals Liquid Crystals 387 (2002) 117.
3. M. Kumar et al, Diamond & Related Materials 12 (2003) 998.
4. M. Kumar et al, Diamond & Related Materials 12 (2003) 1845.
5. M. Kumar et al, Chem. Phys. Lett. 374 (2003) 521.
6. M. Kumar et al, Chem. Phys. Lett. 385 (2004) 161.
7. M. Kumar et al, Carbon 43 (2005) 533.