Conformally coating vertically aligned carbon nanotube arrays using thermal decomposition of iron pentacarbonyl

Conformally coating vertically aligned carbon nanotubes (v-CNT) with metals or oxides can be difficult because standard line-of-sight deposition methods, such as dc sputter coating and electron-beam evaporation, are hindered by the low mean-free-path within the vertically aligned array. In this work, we present a facile method to conformally coat dense arrays of v-CNTs using thermal decomposition of iron pentacarbonyl at 205 °C and 30 mTorr. The resulting coatings were found to be uniform from top-to-bottom across an entire 1 × 1 cm² array of v-CNTs. The thickness of the deposited coating was found to be 2–3 nm/cycle and the resulting film thickness were found to be 13 ± 3 nm after five cycles and 55 ± 5 nm after 20 cycles. This process demonstrates that metal organic chemical vapor deposition can be used to fabricate conformal coatings on v-CNTs.