Electronic transport in locally gated graphene nanoconstrictions

Abstract

We have developed the combination of an etching and deposition technique that enables the fabrication of locally gated graphene nanostructures of arbitrary design. Employing this method, we have fabricated graphene nanoconstrictions with local tunable transmission and characterized their electronic properties. An order of magnitude enhanced gate efficiency is achieved adopting the local gate geometry with thin dielectric gate oxide. A complete turn off of the device is demonstrated as a function of the local gate voltage. Such strong suppression of device conductance was found to be due to both quantum confinement and Coulomb blockade effects in the constricted graphene nanostructures.Comment: 3 pages 3 figures; separated and expanded from arXiv:0705.3044v

Graphene nanoribbons with wings

“…[8][9][10] When measuring the current as a function of the applied BG and bias voltage at constant applied SG voltages, CB diamonds are observed as shown in Fig. 1c.…”

“…7 Experimentally, most graphene nanoribbons show a region of strongly suppressed conductance close to the charge neutrality point. 6,[8][9][10] At sufficiently low temperature, Coulomb blockade is typically observed in this regime of suppressed conductance suggesting that localized charge carriers dominate the electronic transport properties. [8][9][10] Various mechanisms were suggested to be responsible for the observed localization of charge carriers.…”

“…6,[8][9][10] At sufficiently low temperature, Coulomb blockade is typically observed in this regime of suppressed conductance suggesting that localized charge carriers dominate the electronic transport properties. [8][9][10] Various mechanisms were suggested to be responsible for the observed localization of charge carriers. 5,[11][12][13][14][15][16] Recent work has shown that for sufficiently clean devices, edge disorder is mainly responsible for the experimentally observed suppressed conductance 10,17 and that the sites of localized charge can be close to the ribbon edges.…”

“…In agreement with previous experiments, a region of suppressed conductance is found. 6,[8][9][10] This region is typically at positive BG voltages due to unintentional chemical doping of the devices. The measurements discussed in this paper are all recorded in this regime of suppressed conductance.…”

Weighing graphene with QCM to monitor interfacial mass changes

“…It is well known that graphene undergoes chemical oxidation when exposed to plasma. 24 We directly correlate the mass uptake with the structure of graphene using Raman spectrum of graphene after each oxygen plasma exposure (Fig. 6(b)).…”