%0 Journal Article
%T Growth of Single-Walled Carbon Nanotubes by Plasma CVD
%A Toshiaki Kato
%A Rikizo Hatakeyama
%J Journal of Nanotechnology
%D 2010
%I Hindawi Publishing Corporation
%R 10.1155/2010/256906
%X Recent research in plasma chemical vapor deposition (CVD) for single-walled carbon nanotube (SWNT) growth has achieved low-temperature synthesis, individually freestanding formation, and structure control of diameter, chirality, and length. Detailed growth kinetics of SWNTs are revealed using a combination of techniques for plasma control and nanomaterial analysis. Plasma CVD also allows tube metallicity to be controlled by tuning the mean diameter of SWNTs. This plasma CVD progress contributes to the next stage of nanotube fabrication, which is required for practical use of SWNTs in a variety of applications. 1. Introduction One-dimensional single-walled carbon nanotubes (SWNTs) are potential materials for future nanoelectronics [1每5]. Since the electronic and optical properties of SWNTs strongly depend on their structure, such as diameter, chirality, and length, the selective synthesis of SWNTs with desired structures is a major challenge in nanotube science and applications. SWNT growth was first achieved by arc discharge in 1993 [1]. Several growth techniques have been developed since then, including laser ablation [6] and chemical vapor deposition (CVD) [7]. Since it is possible to grow SWNTs at a specific position on a substrate by patterning a catalyst, CVD has attracted much attention in nanoelectronics applications. In general, CVD can be divided into two types: thermal CVD [7每9] and plasma CVD [10每13]. Due to the strong electric fields in plasma sheaths, nanotubes grown by plasma CVD tend to have an individually and vertically freestanding shape [11, 14每16]. Thermal CVD decomposes carbon source gases using thermal energy. In contrast, in plasma CVD, the source gas decomposition is effectively carried out by electron impact with no additional thermal energy; hence, the growth temperature is significantly lower compared to that of thermal CVD [17每19]. Despite these benefits of plasma CVD, it is difficult to control the structure of SWNTs by plasma CVD because there are many unknown factors in plasma, such as ion density, ion energy, radical species, radical densities, and sheath electric field, which restrict the potential application of plasma CVD in nanotube science. Based on previous studies, SWNT growth by plasma CVD has been significantly improved in recent years. Here, we give a brief overview of recent achievements in SWNT growth by plasma CVD. 2. Freestanding Single-Walled Carbon Nanotube Growth The potential of plasma CVD for nanotube growth was first demonstrated by Ren et al. in 1998 [11]. Vertically and individually aligned
%U http://www.hindawi.com/journals/jnt/2010/256906/