▎ 摘　　要

We report on the charging of individual graphene oxide (GO) sheets with varied degrees of reduction by using electrically biased atomic force microscope (AFM) tips. AFM measurements indicate that the apparent height of reduced GO (rGO) sheets increases sharply after charging, while the charging ability is enhanced when the GO sheets are deeply reduced. In addition, the rGO sheets tend to be extracted with electrons (or to be injected with holes) with a positively biased A.FM tip, in contrast to that with a negatively biased tip. Charging on isolated areas with tunable shape and size on single-layered GO has also been achieved. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4765359]