Transition of gas sensing behavior in non-reduced graphene oxides with thermal annealing

Graphene oxide (GO) films were deposited via spin coating on SiO2/Si wafers patterned with interdigitated Pt electrodes. Gas sensing behaviors of GO films and their heat treated films at 200 degrees C in argon atmosphere were characterized. Apparently, non-reduced graphene oxide exhibits n-type and reduced graphene oxide films show p-type behavior on ethanol gas. The change of oxygen functional groups and bond structure are suggested to explain the transition. The combinatorial use of GO and reduced GO (r-GO) in a gas sensor array will provide practical solutions to measure various gases with high selectivity and sensitivity. (C) 2014 Elsevier B.V. All rights reserved.