The aluminum (Al) interlayer with various thicknesses ranging from 0.75 to 6 nm was deposited on silicon (Si) substrates prior to the deposition of ultra-thin iron (Fe) catalyst for the growth of carbon nanotubes. In this paper we report the effect of ultra-thin Al interlayer on the growth of multiwalled carbon nanotubes (MWCNTs). The SEM was used to examine the microstructures of nanotubes. We observed as the Al interlayer thickness increases the height of nanotube decreases. Raman spectra of MWCNT showed typical D and G peaks at similar to 1345 cm(-1) and similar to 1575 cm(-1), respectively. The XPS revealed the presence of Al and Fe on the top of CNT surface which were further supported by TEM. The high resolution TEM results also revealed bamboo like CNTs with diameter similar to 10-40 nm. (C) 2009 Elsevier B.V. All rights reserved.