Graphene−Metal Interface: Two-Terminal Resistance of Low-Mobility Graphene in High Magnetic Fields

Abstract

The two-terminal magnetotransport of a single graphene layer was investigated up to a field of 55 T. The dependence of the electron transmission probability at the organo-metallic interface between the graphene and the metal electrodes was studied as a function of filling factor and electron density. A resistance-plateau spanning several tens of tesla width was observed. We argue that this plateau originates from an augmented sublattice spin-splitting due to the high surface-impurity concentration of the graphene layer. At electron densities close to the Dirac point, fingerprints of a thermally activated energy gap were observed.

Enhanced Shubnikov–De Haas Oscillation in Nitrogen-Doped Graphene

“…Interestingly, the MR curve displays stepped-like behavior, and an unsaturated positive MR of 35% is achieved at 14 T. Similar stepped MR curves were observed for other two-terminal nondoped graphene devices with grapheneÀmetal interfaces. 45 A more detailed analysis of the MR shows there are five distinct field regions: below 0.5 T (I), from 0.5 to 1 T (II), from 1 to 6.7 T (III), from 6.7 to 9 T (IV), and above 9 T (V). The shape of MR curve varies from one region to another.…”

Effect of contact barrier on electron transport in graphene

“…The spectrum shows a strong peak at 2686.4 cm −1 and a weak peak at 1587.9 cm −1 , which is in accordance with the result of monolayer graphene in previous studies. 20,27 After identifying the suitable samples, two-electrode devices were fabricated using electron beam lithography, followed by Cr/Au ͑10/50 nm͒ thermal evaporation and a lift-off process. A Keithley 4200 Semiconductor Characterization System was used to measure the electron transport properties of the fabricated graphene devices.…”

“…In principle, the impurity can be removed through sample heating in vacuum or in argon/hydrogen. 13,[20][21][22][23][24] The impurities, such as organic materials, will result in a barrier between the graphene and electrodes. So it is necessary to study the contact nature between graphene and electrodes, which provides an additional method to investigate the nature of graphene.…”

“…On the other hand, tunneling character of electrons from metal to graphene is also a fundamental and interesting physical property to be studied. 20,25,26 In this work, we fabricated a two-probe graphene device. The device shows nonlinear current-voltage ͑I-V͒ characteristics, indicating the existence of contact barriers.…”

The Surface-Enhanced Raman Spectroscopy of Graphene Deposited by Silver Nanoparticle Islands

“…It has been a focus of attention on the great potential applications in graphene-based electronic devices, such as high-frequency transistors, [2,5] spintronic devices [6,7] and other new molecular-level electronic devices, [5,8] by employing metal atomic-clusters on the graphene to induce the edge defects and artificial defects [9][10][11]. Investigation to the interaction mechanism between graphene and metal atomic-clusters or nanoparticles, is of crucial importance for developing the above-mentioned devices.…”