NO2 and humidity sensing characteristics of few-layer graphenes

Sensing characteristics of few-layer graphenes for NO₂ and humidity have been investigated with graphene samples prepared by the thermal exfoliation of graphitic oxide, conversion of nanodiamond (DG) and arc-discharge of graphite in hydrogen (HG). The sensitivity for NO₂ is found to be highest with DG. Nitrogen-doped HG (n-type) shows increased sensitivity for NO₂ compared with pure HG. The highest sensitivity for humidity is observed with HG. Sensing characteristics of graphene have been examined for different aliphatic alcohols and the sensitivity is found to vary with the chain length and branching.