ABSTRACT
As the applications for carbon nanotubes (CNTs) range from nanoelectronics, sensors, and field emitters to composites, reliable growth techniques capable of yielding high purity material in desirable quantities are critical to realize the potential. Two of the earliest techniques for successful CNT growth are arc synthesis and laser ablation, which were discussed in the previous chapter. Of these two, laser ablation is not amenable for large-scale production, but the arc process is suitable for scale-up to meet the material needs of bulk applications such as composites. The figure of merit for the growth process catering to structural applications is the tons-a-day production ability, in addition to high purity; in contrast, applications such as nanoelectronics, field emission, etc., may require controlled growth on patterned substrates at reasonable rates. This need is satisfied by chemical vapor deposition (CVD) and related techniques, which are categorized according to the energy source. When a conventional heat source such as a resistive or inductive heater, furnace, or IR lamp is used, the technique is called thermal CVD. Note that in the literature the term CVD without any prefix commonly refers to thermal CVD. Plasmaenhanced CVD, or PECVD, refers to the case where a plasma source is used to create a glow discharge.
