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

• Non-reduced graphene oxide films fabricated by a simple spin coating method were demonstrated to measure ethanol gas with high sensitivity.
• Transition from n- to p-type gas sensing behavior was observed by heat treatment of non-reduced graphene oxide.
• The transition from non-reduced to reduced graphene oxide was confirmed using XPS and FTIR.

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 °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.