The effect of a tin oxide buffer layer for the high yield synthesis of carbon nanocoils

In this paper, we show that the efficiency in the growth of carbon nanocoils is significantly improved by introducing a SnO2 buffer layer. Carbon nanocoils were synthesized by chemical vapor deposition using an Fe–Mg–Co or Fe–Mg–Co–Sn catalyst supported on an Al2O3 substrate coated with a 30 nm SnO2 buffer layer. The carbon nanocoil growth rate improved by more than 200% compared with the non-coated substrate when using Fe–Mg–Co–Sn or Fe–Mg–Co catalyst layers 600 or 300 nm thick, respectively. The byproduct layer was also reduced significantly, which results in more than 50% gain in the consumption of carbon source gas during the synthetic process. The role for an external Sn supply from the buffer layer is discussed based on the experimental results.