Unipolar transport in bilayer graphene controlled by multiple p-n   interfaces
  Unipolar transport is demonstrated in a bilayer graphene with a series of p-n junctions and is controlled by electrostatic biasing by a comb-shaped top gate. The OFF state is induced by multiple barriers in the p-n junctions, where the band gap is generated by applying a perpendicular electric field to the bilayer graphene, and the ON state is induced by the p-p or n-n configurations of the junctions. As the number of the junction increases, current suppression in the OFF state is pronounced. The multiple p-n junctions also realize the saturation of the drain current under relatively high source-drain voltages. 
Hisao Miyazaki, Song-Lin Li, Shu Nakaharai, Kazuhito Tsukagoshi
cond-mat.mes-hall cond-mat.mtrl-sci