This article presents an improved graphene oxide synthesis method and its subsequent simple reduction technique with hydrazine vapour more efficiently to produce large area graphene flakes with a dramatic change in average sheet resistance of similar to 145 k Omega/square as compared to existing annealing methods. With the above characteristics, a high-performance and low-voltage operating graphene field-effect transistor (FET) was achieved with the potential to be used as detection platform for biomolecules. (c) 2012 Elsevier B.V. All rights reserved.