Single-walled carbon nanotubes with small diameter, controlled density and defined locations produced from catalyst-containing polymer films
We report CVD growth of single-walled carbon nanotubes (CNTs) using catalyst nanoparticles derived from the catalyst-containing polymers PMGI, PS-b-PVP, and PS-b-PFEMS. Polymeric materials have in general two main advantages in this application: the number of catalyst atoms incorporated in the polymers can be well controlled, and the polymers serve as carriers to distribute the catalyst nanoparticles uniformly across a wafer during spin-coating. CNTs grown from these catalyst nanoparticles are uniformly distributed on the macroscopic scale and have very high quality with a small number of defects and dangling bonds. The typical diameters of these CNTs are less than 2 nm. In some polymers, inorganic elements may be added so that the resultant catalyst nanoparticles are matrixed in an inorganic nanostructure. CNTs grown in this case have diameters of 1 nm or less. Subtractive and additive patterning schemes have been developed to lithographically pattern the catalyst-containing polymeric film for selective growth of CNTs at locations predefined on the micron or even sub-micron scale. The ability to control the catalyst at nano-, micro- and macro-scales greatly enhances the manufacturability of fabricating CNT mats and CNT-based devices for a multitude of biological and electronic applications.
