Comparison of the mechanism of low defect few-layer graphene fabricated on different metals by pulsed laser deposition

Carbon segregation using metal substrates has been given increasing attention as an alternative graphene growth method due to its reduced temperature. However, not every metal behaves in the same manner during the process, hence it is imperative to study their effectiveness when using this growth method. In this paper, few-layer graphene was fabricated on metal substrates with an energetic carbon source supplied by pulsed laser deposition. The ability of Ni, Cu, Co and Fe thin films to form graphene through segregation was investigated. Graphene was fabricated on Ni and absent in Cu, Co and Fe under a specific cooling profile. This was attributed to either low solubility of carbon in Cu and Fe or low carbon diffusion coefficient in Co. However, by adjusting the cooling rate to cater to the carbon diffusion coefficient of Co, low defect few-layer graphene with large substrate coverage was obtained. The results showed that when using PLD, a metal with sufficient carbon solubility is desired over its catalytic ability. The reasons behind the observed phenomena are also discussed. (C) 2012 Elsevier B.V. All rights reserved.