Effects of Al buffer layer on growth of highly vertically aligned carbon nanotube forests for in situ yarning

Abstract

In this study, effects of aluminum (Al) buffer layer on synthesis of highly vertically aligned carbon nanotube (CNT) forests were systematically studied. Tens of nanometer thick Al layer was introduced between iron (Fe) catalytic layer and Si substrate. Highly vertically aligned CNT forests have been synthesized using chemical vapor deposition (CVD) system on iron (Fe) nano-particles catalyzed substrate supported by thin aluminum (Al) buffer layer. The thickness of Fe and Al layer was varied to obtain optimal substrate conditions suitable for highly vertically aligned CNT forest, result in yarned CNTs. Marked differences were observed both thermally treated substrates and verticallinity of CNT forests depending on the thickness of Fe and Al layer. Highly vertically aligned CNT forest was obtained with Fe/Al thickness of 0.5 and 40 nm, respectively. The maximum height of 1.33 mm CNT forests which has high verticallinity and density was synthesized in 15 min of growth time, corresponds to 87 μm/min of growth rate. The growth rate of 87 μm/min is relatively high compared with other reports. Additionally, yarned CNT fibers were spun from grown CNT forests for applications to reinforced materials.