Electronic transport in helium-ion-beam etched encapsulated graphene nanoribbons

Electronic transport in helium-ion-beam etched encapsulated graphene nanoribbons

Nanda, G. (TU Delft QN/Kavli Nanolab Delft; Kavli institute of nanoscience Delft)
Hlawacek, Gregor (Institut für Ionenstrahlphysik und Materialforschung)
Goswami, S. (TU Delft QRD/Goswami Lab; TU Delft QN/Quantum Transport; TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft)
Watanabe, Kenji (National Institute for Materials Science)
Taniguchi, Takashi (National Institute for Materials Science)
Alkemade, P.F.A. (TU Delft QN/Kavli Nanolab Delft; Kavli institute of nanoscience Delft)

2017

We report the etching of and electronic transport in nanoribbons of graphene sandwiched between atomically flat hexagonal boron nitride (h-BN). The etching of ribbons of varying width was achieved with a focused beam of 30 keV He⁺ ions. Using in-situ electrical measurements, we established a critical dose of 7000 ions nm⁻² for creating a 10 nm wide insulating barrier between a nanoribbon and the rest of the encapsulated graphene. Subsequently, we measured the transport properties of the ion-beam etched graphene nanoribbons. Conductance measurements at 4 K show an energy gap, that increases with decreasing ribbon width. The narrowest ribbons show a weak dependence of the conductance on the Fermi energy. Furthermore, we observed power-law scaling in the measured current-voltage (I-V) curves, indicating that the conductance in the helium-ion-beam etched encapsulated graphene nanoribbons is governed by Coulomb blockade.

Bandgap
Electronic transport
Graphene
Graphene nanoribbons
h-BN
Helium ion microsope

http://resolver.tudelft.nl/uuid:3674b3a3-5604-4b1f-907d-64c656b95bb0

https://doi.org/10.1016/j.carbon.2017.04.062

0008-6223

Carbon, 119, 419-425

Institutional Repository

journal article

© 2017 G. Nanda, Gregor Hlawacek, S. Goswami, Kenji Watanabe, Takashi Taniguchi, P.F.A. Alkemade