Quantum Hall Effect In Monolayer, Bilayer And Trilayer Graphene

We have performed magneto-transport experiments in monolayer, bilayer, trilayer and four layered graphene, at temperatures between 2 and 190 K and magnetic fields up to 28 T. In particular, in monolayer graphene we studied the quantum Hall effect and the metal-insulator transition. On the other hand, in bilayer graphene we observed quantum Hall plateaus at filling factor v = 4, 8,12,16,20, ... and the v = 6 plateau in trilayer graphene, studying their temperature dependence. We have also studied the symmetry properties which are related with different contact configurations describing the method used to study inhomogeneus samples. Finally, four layered graphene we did not found quantum Hall plateaus, but we observed and investigated an ambipolar conduction effect.