Electrical transport across metal/two-dimensional carbon junctions: Edge   versus side contacts
  Metal/two-dimensional carbon junctions are characterized by using a nanoprobe in an ultrahigh vacuum environment. Significant differences were found in bias voltage (V) dependence of differential conductance (dI/dV) between edge- and side-contact; the former exhibits a clear linear relationship (i.e., dI/dV \propto V), whereas the latter is characterized by a nonlinear dependence, dI/dV \propto V3/2. Theoretical calculations confirm the experimental results, which are due to the robust two-dimensional nature of the carbon materials under study. Our work demonstrates the importance of contact geometry in graphene-based electronic devices. 
Yihong Wu, Ying Wang, Jiayi Wang, Miao Zhou, Aihua Zhang, Chun Zhang,   Yanjing Yang, Younan Hua and Baoxi Xu
cond-mat.mes-hall