▎ 摘　　要

Many studies have characterized disordered graphene layers as variable-range hopping and activated hopping conduction for a graphene structure with planar left and right electrodes. We report the electrical transport measurements of atomic-thick-graphene with top and bottom Ti/Pt electrodes. In the vertical device of metal-graphene-metal under a transverse electric field, the current at the low field or high temperature was explained by bulk-limited conduction, so called Ohmic current. On the other hand, space-charge-limited-conduction dominated at low temperatures or under high fields. The estimated trap concentration for the high field or low temperature conduction was approximately 3.7 x 10(17) cm(-3), and from a cessation of the power law dependence in the J-V characteristics it was determined that the onset of failure breakdown of the vertical GL structure began after dissipating power of 2.7 x 10(12) W m(-3). (C) 2011 American Institute of Physics. [doi:10.1063/1.3569722]