Influence of post-treatment processes on the morphology of Fe-catalyst and the characteristics of the subsequently grown carbon nanotubes were systematically investigated. The reducing agent, which is either H-2 gases species or cracked ammonia, NH3, imposed most marked effect on the morphology of Fe-clusters. The Fe-catalysts, which were prepared from 0.1 M Fe(OR)(3) in xylene and were reduced by NH3 gas species, are nano-sized (50 nm), isolated and uniformly distributed. They result in carbon nanotubes of the highest purity and most density populated, exhibiting the largest electron field emission capacity. The Fe catalysts prepared by other conditions are interconnected or coarsened particulates, which induces the formation of carbon soots. The electron field emission capacity of the CNTs films is thus markedly decreased. These results imply that spin coating of Fe(OR), is a simple and inexpensive method for preparing catalyst of good quality, which can produce high purity carbon nanotubes, provided that the processing parameters are well controlled. A simple and inexpensive method for preparing Fe-catalyst of good quality, spin coating of Fe(OR), technique, was developed. This technique has the potential for scaling up and for selectively growing CNTs for electron emitters' application.