A ballistic pn junction in suspended graphene with split bottom gates (original) (raw)

We have developed a process to fabricate suspended graphene devices with local bottom gates, and tested it by realizing electrostatically controlled pn junctions on a suspended graphene mono-layer nearly 2 µm long. Measurements as a function of gate voltage, magnetic field, bias, and temperature exhibit characteristic Fabry-Perot oscillations in the cavities formed by the pn junction and each of the contacts, with transport occurring in the ballistic regime. Our results demonstrate the possibility to achieve a high degree of control on the local electronic properties of ultra-clean suspended graphene layers, a key aspect for the realization of new graphene nanostructures. PACS numbers: 73.63.-b, 72.80.Vp, 73.40.-c, 07.60.Ly a) Alberto.Morpurgo@unige.ch 1 arXiv:1304.6844v1 [cond-mat.mes-hall]