Page 50 - Principles and Applications of NanoMEMS Physics

36 Chapter 1

1.2.3.5 Carbon Nanotubes

Carbon nanotubes are, perhaps, the quintessential element of
nanotechnology. Their discovery is the fruit of research, originally
conducted by Kroto and Smalley in 1985, with the aim of studying the laser
vaporization of graphite. Such studies elicited the discovery by them of
clusters containing 60 carbon atoms (C 60: Buckminsterfullerene), arranged in
a spherical structure, see Figure 1-31, [1].

Figure 1-31. Sketch of the chemical structure of C 60 : Buckminsterfullerene. (After [46].)

Continued research to increase the yield of these C 60 clusters led Iijima to
discover carbon nanotubes (CNT), see Figure 1-33 [46].

Figure 1-32. (a) Sketch of the chemical structure of a single-wall carbon nanotube (SWNT).
(After [1].) (b) SEM of SWNT and MWNT. In a multi-walled nanotube, an inner SWNT
forms the core of multiple concentric nanotubes which grow around it. (Courtesy of Prof.
László Forró, Swiss Federal Institute of Technology (EPFL), Lausanne Switzerland).

CNTs are molecular carbon fibers that consist of graphite cylinders
closed at each end by caps containing six pentagonal rings, i.e., each cap is
exactly one-half of a C 60 molecular cluster [46]. They tend to be produced in