The surface I-V behaviors of the 1, 3, and 5 min graphene samples. (a) 1 min sample. The inset shows the electrodes’ layout on the surface of the graphene film. (b) 3 min sample. (c) 5 min sample.
Ma and Zhang Nanoscale Research Letters 2013 8:440 doi:10.1186/1556-276X-8-440