Graphene ribbons contacted from top on Al2O3 substrates with nickel contacts. The FET measurements were taken between two inner electrodes as source and drain, and substrate was gated from back. On the right, an Isd - Vg characteristic of the device is shown at Vsd of 50 mV.
Kumar et al. Nanoscale Research Letters 2011 6:390 doi:10.1186/1556-276X-6-390