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Graphene nanoribbons with smooth edges behave as quantum wires

Nature Nanotechnology volume 6, pages 563–567 (2011)Cite this article

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Abstract

Graphene nanoribbons with perfect edges are predicted to exhibit interesting electronic and spintronic properties1,2,3,4, notably quantum-confined bandgaps and magnetic edge states. However, so far, graphene nanoribbons produced by lithography have had rough edges, as well as low-temperature transport characteristics dominated by defects (mainly variable range hopping between localized states in a transport gap near the Dirac point5,6,7,8,9). Here, we report that one- and two-layer nanoribbon quantum dots made by unzipping carbon nanotubes10 exhibit well-defined quantum transport phenomena, including Coulomb blockade, the Kondo effect, clear excited states up to ∼20 meV, and inelastic co-tunnelling. Together with the signatures of intrinsic quantum-confined bandgaps and high conductivities, our data indicate that the nanoribbons behave as clean quantum wires at low temperatures, and are not dominated by defects.

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Figure 1: High-quality unzipping-derived graphene nanoribbons.
Figure 2: Electron transport of GNR1 (L ≈ 86 nm).
Figure 3: Electron transport of a high-quality quantum dot in GNR2 (L ≈ 140 nm).
Figure 4: Electron transport of GNR3 (L ≈ 60 nm).

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Acknowledgements

The authors thank D. Goldhaber-Gordon for helpful discussions. The work at Stanford was supported in part by the Office of Naval Research (ONR), the ONR Graphene MURI, MARCO MSD Focus Center and Intel. Aberration corrected transmission electron microscopy was performed at the NCEM at Lawrence Berkeley Lab, which was supported by the US Department of Energy (contract no. DE-AC02-05CH11231). The work at University of Florida was supported in part by the National Science Foundation (NSF) and the ONR.

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  1. Xinran Wang

    Present address: Present address: Department of Material Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA,

Authors and Affiliations

  1. Department of Chemistry, Stanford University, Stanford, 94305, California, USA

    Xinran Wang, Liying Jiao, Hailiang Wang, Liming Xie, Justin Wu & Hongjie Dai

  2. National Laboratory of Microstructures, School of Electronic Science and Engineering, Nanjing University, Nanjing, 210093, China

    Xinran Wang

  3. Department of Electrical and Computer Engineering, University of Florida, Gainesville, 32611, Florida, USA

    Yijian Ouyang & Jing Guo

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Contributions

X.W. and H.D. conceived and designed the experiments. X.W. and J.W. fabricated the devices, performed the experiments and analysed the data. Y.O. and J.G. performed simulations. L.J. provided graphene nanoribbon samples. H.W. and L.X. performed TEM characterizations. X.W., Y.O., J.G. and H.D. co-wrote the paper. All authors discussed the results and commented on the manuscript.

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Correspondence to Hongjie Dai.

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Wang, X., Ouyang, Y., Jiao, L. et al. Graphene nanoribbons with smooth edges behave as quantum wires. Nature Nanotech 6, 563–567 (2011). https://doi.org/10.1038/nnano.2011.138

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