The mechanism of graphene oxide as a growth template for complete reduced graphene oxide coverage on an SiO2 substrate

Reduced Graphene Oxide (rGO) has the distinct advantage of an aqueous and industrial-scalable production route. However large deviation in the electrical resistivity of fabricated rGO devices, caused by inhomogeneous coverage of rGO on the substrate, prevents its practical application in electronic devices. This critical problem could be solved by using an ethanol chemical vapour deposition (CVD) treatment on graphene oxide (GO). With the treatment, not only GO is reduced to rGO, but also rGO preferentially grows outwards from the edges of the existing GO template and enlarge in size until rGO completely covers the substrate. The growth sequence is presented and our results indicate that the growth supports the free radical condensate growth mechanism. After the ethanol CVD treatment, the standard deviation in electrical resistivity decreased significantly by 99.95% (1.60 x 10(6) to 7.72 x 10(2) Omega per square) in comparison with hydrazine-reduced rGO substrates. As no carbon signatures on the substrate were observed when no template was used, this work indicates that GO could act as a template for subsequent formation of rGO.