Magneto-Transport Properties of Exfoliated Graphene on GaAs
  We studied the magneto-transport properties of graphene prepared by exfoliation on a III V semiconductor substrate. Tuneability of the carrier density of graphene was achieved by using a doped GaAs substrate as a back-gate. A GaAs/AlAs multilayer, designed to render the exfoliated graphene flakes visible, also provides the required back-gate insulation. Good tuneability of the graphene carrier density is obtained, and the typical Dirac resistance characteristic is observed despite the limited height of the multilayer barrier compared to the usual SiO2 oxide barrier on doped silicon. In a magnetic field weak localization effects as well as the quantum Hall effect of a graphene monolayer are studied. 
Miros{\l}aw Woszczyna, Miriam Friedemann, Klaus Pierz, Thomas Weimann,   and Franz J. Ahlers
cond-mat.mes-hall