Oxygen sensors made by monolayer graphene under room temperature

The electrical resistivity of monolayer graphene exhibit significant changes upon expose to different concentration of oxygen (O-2) at room temperature. The monolayer graphene, grown by chemical vapor deposition with perfect uniformity within 1 cm x 1 cm will attach O-2 molecules and enhance the hole conductivity, which will lead to a change of resistivity of graphene thin film. We quantified the change of resistivity of graphene versus different O-2 concentration and the detection limit of the simple O-2 sensor was 1.25% in volume ratio. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3668105]