Synthesis of vertically-aligned CNT arrays from diameter-controlled Fe₃O₄ nanoparticles

Abstract

Almost monodisperse Fe 3 O 4 nanoparticles (NPs) with four distinct mean sizes prepared by thermal decomposition were selfassembled onto a silicon substrate in the form of multi-layers using a simple drop-drying method. These multilayered Fe 3 O 4 NPs were used as the catalysts to grow vertically-aligned carbon nanotube arrays (VACNTAs) by chemical vapor deposition (CVD). The correlation between the CNT diameter and the NP size was determined. Catalysts with different sizes play a vital role in influencing the diameters and structures of CVD-grown CNTs. In addition, the size of the catalyst NPs is a critical factor for obtaining dense arrays of VACNTs. This method is a relatively simple and environmental friendly process compared to previous methods, and has the potential for the mass production of VACNTAs.