Growth of graphene from solid carbon sources

Abstract

Monolayer graphene was first obtained as a transferable material in 2004 and has stimulated intense activity among physicists, chemists and material scientists. Much research has been focused on developing routes for obtaining large sheets of monolayer or bilayer graphene. This has been recently achieved by chemical vapour deposition (CVD) of CH(4) or C(2)H(2) gases on copper or nickel substrates. But CVD is limited to the use of gaseous raw materials, making it difficult to apply the technology to a wider variety of potential feedstocks. Here we demonstrate that large area, high-quality graphene with controllable thickness can be grown from different solid carbon sources-such as polymer films or small molecules-deposited on a metal catalyst substrate at temperatures as low as 800 °C. Both pristine graphene and doped graphene were grown with this one-step process using the same experimental set-up.

Near room-temperature synthesis of transfer-free graphene films

“…The electrical properties of graphene layers on SiO 2 /Si(100) obtained at T = 160 °C and t = 5 min have been evaluated with backgated graphene-based field-effect transistor (FET) devices and typical data for the FET devices are shown in Figure 1g and Supplementary Figure S3a. The 'V' shape of the ambipolar transfer characteristics and the shift of neutrality point to positive gate voltage, that is, weak p-type behaviour 1,12,21 , in ambient conditions are observed, all expected electrical properties for graphene-based FETs. The estimated carrier (hole) mobility of this particular device in ambient conditions is ~667 cm 2 V − 1 s − 1 at room temperature, suggesting that the as-synthesized graphene films are of reasonable quality.…”

“…Among all of the potential applications for graphene, realization of graphene-based flexible electronic display technology appears to be closer to reality 8 . Currently, large-area graphene films are best synthesized via pyrolytic cracking of hydrocarbon gases [8][9][10][11] and/or a solid deposition method 12 at elevated temperatures (~1,000 °C) on polycrystalline metal surfaces and later transferred onto other substrates for the fabrication of devices. However, the high growth temperatures impose limitations on the choice of substrates and the subsequent transferability of as-grown layers influence device performance.…”

Monolithic graphene oxide sheets with controllable composition

“…These spectra indicate the significant presence of foreign species in the graphene framework. The spectra for all of the samples exhibit three primary features: a D band at B1,348 cm À 1 , a G band at B1,592 cm À 1 and a 2D band at B2,687 cm À 1 , which are all typical peak positions for graphene 14,[16][17][18][19][20][21] . However, the Raman spectra of the samples consistently show an intense D band (I D /I G Z1.0) related to domain boundaries, impurities and growth-nucleation sites [22][23][24][25] .…”

“…In contrast to pristine graphene that has no bandgap [17][18][19] , however, the optical bandgaps of the graphene frameworks that were transferred onto quartz were measured to be B2.21 eV, based on UV-vis spectroscopy (Fig. 1j, inset), suggesting the presence of foreign species in the graphene framework 28,29 .…”

Terahertz and Infrared Spectroscopy of Gated Large-Area Graphene

“…Our samples were grown from a solid-state carbon source 29 -poly(methyl methacrylate) (PMMA) in the present case. 30 A thin copper foil of centimeter scale was spin coated with PMMA and then placed in the growth furnace. At a temperature between 800 and 1000˚C, a reductive H 2 /Ar gas flow was introduced under low-pressure conditions, and after ~10 minutes, a single uniform layer of large-area graphene was formed.…”