Vertical graphene gas- and bio-sensors via catalyst-free, reactive plasma reforming of natural honey

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.