Reduction of carbon byproducts for high-purity carbon nanocoil growth by suppressing catalyst collision

Carbon nanocoils (CNC) are promising nanocarbon materials for application as functional composites such as electromagnetic wave absorbers. However, the suppression of carbon byproducts during CNC growth is necessary to obtain high purity CNCs with high yield. Here, we demonstrate a simple but efficient method for the reduction of carbon byproducts using a patterned thin film catalyst. Results show that the collision of tip catalysts of growing CNCs to the substrate or other CNCs inhibits the smooth growth of CNCs because of the deactivation of the catalyst. The collision also stimulates the formation of a carbon byproduct layer underneath the CNC layer. The well-controlled thin film catalyst with checkerboard pattern brings us four-times-higher efficiency of the catalyst and suppresses the carbon byproduct layer to ∼1/3.