Magnetotransport of polycrystalline graphene: Shubnikov-de Haas oscillation and weak localization study

Magnetotransport measurements were performed on a cross-junction made from polycrystalline graphene grown at a low temperature. The Shubnikov-de Haas oscillation is observed, from which the cyclotron mass m_c can be derived varying from 0.043 to 0.055 times that of free electron. The changing rate of electron temperature is found much lower than that in pristine graphene via the universal electron heating study. Investigations on the characteristic lengths of weak localization reveal that the atomically sharp defects dominate the elastic scattering process, while studies on the coherent rate report that the Nyquist effect governs the inelastic scattering process with a little modulation from the direct Coulomb interaction. The scattering lengths in the polycrystalline graphene are comparable to that of exfoliated graphene on SiO₂. These findings indicate that some key scattering parameters which characterize the excellent properties of intrinsic graphene are preserved in the polycrystalline graphene, which may find potential applications in interconnects of integrated circuit.