Effect of Superparamagnetic Fe3O4 Nanoparticles on Schottky Barriers of Graphene

We demonstrated the effect of superparamagnetic Fe₃O₄ nanoparticles on the Schottky barriers of graphene, in which the Fe₃O₄ nanoparticles were fabricated by a hydrothermal method, and the single-layer graphene sheets were mechanically exfoliated from Kish graphite. The Fe₃O₄ nanoparticles were superparamagnetic with the saturation magnetic moment of ~32emu/g at room temperature. We have found that the Fe₃O₄ nanoparticles decorated on the graphene surface can dramatically modify the Schottky barriers of the whole devices possibly due to the magnetic stray field from the Fe₃O₄ nanoparticles in proximity to graphene. The Schottky barrier could be further tuned by the quantity of Fe₃O₄ nanoparticles.