  Sensing characteristics of few-layer graphenes for NO2 and humidity have been
investigated with graphene samples prepared by the thermal exfoliation of
graphitic oxide (EG), 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 to
pure HG. The highest sensitivity for humidity is observed with HG. The sensing
characteristics of graphene have been examined for different aliphatic alcohols
and the sensitivity is found to vary with the chain length and branching.
