The growth of vertical single-walled carbon nanotube (SWNT) arrays of uniform aerial distribution is
achieved by oxygen assisted plasma enhanced chemical vapor deposition (PECVD) growth from
nanopatterned catalyst arrays prepared by block copolymer lithography. Block copolymer lithography is
an attractive nanopatterning method for generating a uniform catalyst particle array for carbon nanotube
growth. Nevertheless, the scale of the catalyst particles patterned by block copolymer lithography is
usually not small enough for SWNT growth. In this work, various methods to reduce the catalyst size
have been investigated for SWNT growth. Nanopatterned iron catalyst arrays having a mean diameter of
9 nm were prepared via tilted evaporation of thin iron catalyst films over a block copolymer template
with the nanopore size of 20 nm, followed by heat treatment at 600 °C. The catalyst particle size was
further reduced to the size required for SWNT growth (∼3 nm) by the following two methods. In method
i, the catalyst particles were sequentially annealed at 800 °C first in air and then in an H2 atmosphere.
The evaporation of iron atoms and subsequent reduction during heat treatment produced catalyst particles
sufficiently small for SWNT growth. In method ii, an Al layer was deposited over the catalyst array,
which decreased the exposed area of the catalyst particles. The effective catalyst particle size was thus
reduced, which enabled the growth of SWNTs.