Abstract
Graphene shows promise as a future material for nanoelectronics owing to its compatibility with industry-standard lithographic processing, electron mobilities up to 150 times greater than Si and a thermal conductivity twice that of diamond. The electronic structure of graphene nanoribbons (GNRs) and quantum dots (GQDs) has been predicted to depend sensitively on the crystallographic orientation of their edges; however, the influence of edge structure has not been verified experimentally. Here, we use tunnelling spectroscopy to show that the electronic structure of GNRs and GQDs with 2–20 nm lateral dimensions varies on the basis of the graphene edge lattice symmetry. Predominantly zigzag-edge GQDs with 7–8 nm average dimensions are metallic owing to the presence of zigzag edge states. GNRs with a higher fraction of zigzag edges exhibit a smaller energy gap than a predominantly armchair-edge ribbon of similar width, and the magnitudes of the measured GNR energy gaps agree with recent theoretical calculations.
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References
Bardeen, J. Surface states and rectification at a metal–semiconductor contact. Phys. Rev. 71, 717–727 (1947).
Kilby, J. S. Miniaturized electronic circuit. US Patent No. 3,138,743 (Issued June 23, 1964; Filed Feb. 6, 1959).
Ponomarenko, L. A. et al. Chaotic Dirac billiard in graphene quantum dots. Science 320, 356–358 (2008).
Han, M. Y., Özyilmaz, B., Zhang, Y. & Kim, P. Energy band gap engineering of graphene nanoribbons. Phys. Rev. Lett. 98, 206805 (2007).
Chen, Z., Lin, Y., Rooks, M. J. & Avouris, P. Graphene-nanoribbon electronics. Physica E 40, 228–232 (2007).
Li, X., Wang, X., Zhang, L., Lee, S. & Dai, H. Chemically derived, ultrasmooth graphene nanoribbon semiconductors. Science 319, 1229–1232 (2008).
Lin, Y.-M., Perebeinos, V., Chen, Z. & Avouris, P. Conductance quantization in graphene nanoribbons. Preprint at <http://arxiv.org/abs/0805.0035> (2008).
Adam, S., Cho, S., Fuhrer, M. S. & Das Sarma, S. Density inhomogeneity driven percolation metal–insulator transition and dimensional crossover in graphene nanoribbons. Phys. Rev. Lett. 101, 046404 (2008).
Son, Y.-W., Cohen, M. L. & Louie, S. G. Energy gaps in graphene nanoribbons. Phys. Rev. Lett. 97, 216803 (2006).
Barone, V., Hod, O. & Scuseria, G. E. Electronic structure and stability of semiconducting graphene nanoribbons. Nano Lett. 6, 2748–2754 (2006).
Son, Y.-W., Cohen, M. M. & Louie, S. G. Half-metallic graphene nanoribbons. Nature 444, 347–349 (2006).
Fujita, M., Wakabayashi, K., Nakada, K. & Kusakabe, K. Peculiar localized state at zigzag graphite edge. J. Phys. Soc. Jpn. 65, 1920–1923 (1996).
Sols, F., Guinea, F. & Castro Neto, A. H. Coulomb blockade in graphene nanoribbons. Phys. Rev. Lett. 99, 166803 (2007).
Querlioz, D. et al. Suppression of the orientation effects on bandgap in graphene nanoribbons in the presence of edge disorder. Appl. Phys. Lett. 92, 42108 (2008).
Gunlycke, D., Areshkin, D. A. & White, C. T. Semiconducting graphene nanostrips with edge disorder. Appl. Phys. Lett. 90, 142104 (2007).
Ritter, K. A. & Lyding, J. W. Characterization of nanometer-sized, mechanically exfoliated graphene on the H-passivated Si(100) surface using scanning tunneling microscopy. Nanotechnology 19, 015704 (2008).
Ishigami, M., Chen, J. H., Cullen, W. G., Fuhrer, M. S. & Williams, E. D. Atomic structure of graphene on SiO2 . Nano Lett. 7, 1643–1648 (2007).
Stolyarova, E. et al. High-resolution scanning tunneling microscopy imaging of mesoscopic graphene sheets on an insulating surface. Proc. Natl Acad. Sci. 104, 9209–9212 (2007).
Kobayashi, Y., Fukui, K., Enoki, T. & Kusakabe, K. Edge state on hydrogen-terminated graphite edges investigated by scanning tunneling microscopy. Phys. Rev. B 73, 125415 (2006).
Kobayashi, Y., Fukui, K., Enoki, T., Kusakabe, K. & Kaburagi, Y. Observation of zigzag and armchair edges of graphite using scanning tunneling microscopy and spectroscopy. Phys. Rev. B 71, 193406 (2005).
Nimi, Y. et al. Scanning tunneling microscopy and spectroscopy of the electronic local density of states of graphite surfaces near monoatomic step edges. Phys. Rev. B 73, 085421 (2006).
Rutter, G. M. et al. Scattering and interference in epitaxial graphene. Science 317, 219–222 (2007).
Tapasztó, L., Dobrik, G., Lambin, P. & Biró, L. P. Tailoring the atomic structure of graphene nanoribbons using scanning tunneling microscope lithography. Nature Nanotech. 3, 397–401 (2008).
Piva, P. G. et al. Field regulation of single-molecule conductivity by a charged surface atom. Nature 435, 658–661 (2005).
Liu, L., Yu, J. & Lyding, J. W. Atom-resolved three-dimensional mapping of boron dopants in Si(100) by scanning tunneling microscopy. Appl. Phys. Lett. 78, 386–388 (2001).
Berger, C. et al. Electronic confinement and coherence in patterned epitaxial graphene. Science 312, 1191–1196 (2006).
Geim, A. K. & Novoselov, K. S. The rise of graphene. Nature Mater. 6, 183–191 (2007).
Nakada, K., Fujita, M., Dresselhaus, G. & Dresselhaus, M. S. Edge state in graphene ribbons: Nanometer size effect and edge shape dependence. Phys. Rev. B. 54, 17954–17960 (1996).
Klusek, Z. et al. Observation of local electron states on the edges of circular pits on hydrogen-etched graphite surface by scanning tunneling spectroscopy. Appl. Surf. Sci. 161, 508–514 (2000).
Zhang, Z. Z., Chang, K. & Peeters, F. M. Tuning of energy levels and optical properties of graphene quantum dots. Phys. Rev. B 77, 235411 (2008).
Datta, S. S., Strachan, D. R., Khamis, S. M. & Johnson, A. T. C. Crystallographic etching of few-layer graphene. Nano Lett. 8, 1912–1915 (2008).
Lyding, J. W., Skala, S., Hubacek, J. S., Brockenbrough, R. & Gammie, G. Variable-temperature scanning tunneling microscope. Rev. Sci. Instrum. 59, 1897–1902 (1988).
Feenstra, R. M. Tunneling spectroscopy of the (110) surface of direct-gap III–V semiconductors. Phys. Rev. B 50, 4561–4570 (1994).
Albrecht, P. M. & Lyding, J. W. Ultrahigh-vacuum scanning tunneling microscopy and spectroscopy of single-walled carbon nanotubes on hydrogen-passivated Si(100) surfaces. Appl. Phys. Lett. 83, 5029–5031 (2003).
Acknowledgements
This work was supported by the Office of Naval Research under grant number N000140610120 and by the National Science Foundation grant number NSF ECS 04-03489. K.A.R. acknowledges support from a NDSEG fellowship. We thank J. Koepke for assistance with a portion of the data collection, L. Ruppalt for providing the code for the normalized dI/dV calculations and P. Albrecht, P. Dollfus, D. Querlioz, A. Rockett, M. Sztelle and J. Weaver for helpful discussions.
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K.A.R and J.W.L. conceived the experiments. K.A.R. carried out the experiments, analysed the data and wrote the manuscript. J.W.L. provided technical support for the instrumentation, discussed the data and commented on the manuscript.
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Ritter, K., Lyding, J. The influence of edge structure on the electronic properties of graphene quantum dots and nanoribbons. Nature Mater 8, 235–242 (2009). https://doi.org/10.1038/nmat2378
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DOI: https://doi.org/10.1038/nmat2378
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