Role of substrate, temperature, and hydrogen on the flame synthesis of graphene films

Graphene films are grown in open-atmosphere on metal substrates using a multiple inverse-diffusion flame burner with methane as fuel. Substrate material (i.e. copper, nickel, cobalt, iron, and copper-nickel alloy), along with its temperature and hydrogen treatment, strongly impacts the quality and uniformity of the graphene films. The growth of few-layer graphene (FLG) occurs in the temperature range 750-950 degrees C for copper and 600-850 degrees C for nickel and cobalt. For iron, the growth of graphene is not exclusively observed. The variation of graphene quality for different substrates is believed to be due primarily to the difference in carbon solubility between the metals. (C) 2012 The Combustion Institute. Published by Elsevier Inc. All rights reserved.