Flame synthesis of graphene films in open environments

Abstract

Few-layer graphene (FLG) is grown on copper and nickel substrates at high rates using a novel flame synthesis method in open-atmosphere environments. Transmittance and resistance properties of the transferred films are similar to those grown by other methods, but the concentration of oxygen, as assessed by XPS, is actually less than that for CVD-grown graphene under near vacuum conditions. The method involves utilizing a multi-element inverse-diffusionflame burner, where post-flame species and temperatures are radially-uniform upon deposition at a substrate. Advantages of the flame synthesis method are scalability for large-area surface coverage, increased growth rates, high purity and yield, continuous processing, and reduced costs due to efficient use of fuel as both heat source and reagent. Additionally, by adjusting local growth conditions, other carbon nanostructures (i.e. nanotubes) are readily synthesized.

Synthesis of Large-Area Few-Layer Graphene by Open-Flame Deposition

“…However, lower values for I 2D /I G indicate the increasing amount of graphene layer; thus, the deposit thickness is actually increasing. According to Memon et al (2011), the 514 nm Raman spectroscopy showed that flame-deposited graphene on Cu yielded I 2D /I G and I D /I G ratios of 0.74 and 0.35 for ratio at 950°C. By comparison, at 0.2 atm H 2 , the 750°C reaction temperature yielded I 2D /I G and I D /I G ratios of 0.82 and 0.88 thereby showing that even at temperatures lower than those reported by Memon et al (2011), we could obtain an even thinner multilayer graphene film but at an increased disorder.…”

“…Similar to plasma-enhanced CVD which was reported by various groups to have improved the resulting graphene (Chan et al 2013;Jacob et al 2015), flame is another form of plasma that is expected to exert a similar positive effect on the graphene synthesis. In fact, researchers have reported on the formation of few-layer graphene through open-flame deposition (Li et al 2011;Liu et al 2016;Memon et al 2011). However, Memon et al (2011) showed that the reaction temperature was still extremely high at 950°C.…”

“…In fact, researchers have reported on the formation of few-layer graphene through open-flame deposition (Li et al 2011;Liu et al 2016;Memon et al 2011). However, Memon et al (2011) showed that the reaction temperature was still extremely high at 950°C. Despite so, this is a promising method because markedly simplifies the CVD setup thereby allowing an economical and facile production of graphene.…”

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“…According to Memon et al (2011), the 514 nm Raman spectroscopy showed that flame-deposited graphene on Cu yielded I 2D /I G and I D /I G ratios of 0.74 and 0.35 for ratio at 950°C. By comparison, at 0.2 atm H 2 , the 750°C reaction temperature yielded I 2D /I G and I D /I G ratios of 0.82 and 0.88 thereby showing that even at temperatures lower than those reported by Memon et al (2011), we could obtain an even thinner multilayer graphene film but at an increased disorder. Various groups have remarked on the positive effect of hydrogen gas (Vlassiouk et al 2011;Zhang et al 2014), which improves the quality of the multilayer graphene; the results of the present study are in accordance with the findings of other researchers.…”

“…Therefore, a markedly thicker disordered graphite is required to achieve this film conductivity. Few-layer graphene obtained by Memon et al (2011) was reported to possess 40 kΩ/square sheet resistance at 86% transmittance.…”