Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Cross-sectional imaging of individual layers and buried interfaces of graphene-based heterostructures and superlattices

Abstract

By stacking various two-dimensional (2D) atomic crystals1 on top of each other, it is possible to create multilayer heterostructures and devices with designed electronic properties2,3,4,5. However, various adsorbates become trapped between layers during their assembly, and this not only affects the resulting quality but also prevents the formation of a true artificial layered crystal upheld by van der Waals interaction, creating instead a laminate glued together by contamination. Transmission electron microscopy (TEM) has shown that graphene and boron nitride monolayers, the two best characterized 2D crystals, are densely covered with hydrocarbons (even after thermal annealing in high vacuum) and exhibit only small clean patches suitable for atomic resolution imaging6,7,8,9,10. This observation seems detrimental for any realistic prospect of creating van der Waals materials and heterostructures with atomically sharp interfaces. Here we employ cross sectional TEM to take a side view of several graphene–boron nitride heterostructures. We find that the trapped hydrocarbons segregate into isolated pockets, leaving the interfaces atomically clean. Moreover, we observe a clear correlation between interface roughness and the electronic quality of encapsulated graphene. This work proves the concept of heterostructures assembled with atomic layer precision and provides their first TEM images.

This is a preview of subscription content, access via your institution

Relevant articles

Open Access articles citing this article.

Access options

Buy article

Get time limited or full article access on ReadCube.

$32.00

All prices are NET prices.

Figure 1: Cross-sectional TEM of graphene–hBN heterostructures.
Figure 2: Characterization of chemical species trapped between layers.
Figure 3: Graphene–BN superlattice.

References

  1. Novoselov, K. S. et al. Two-dimensional atomic crystals. Proc. Natl Acad. Sci. USA 102, 10451–10453 (2005).

    Article  CAS  Google Scholar 

  2. Wang, H. et al. BN/Graphene/BN transistors for RF applications. IEEE Electron Device Lett. 32, 1209–1211 (2011).

    Article  CAS  Google Scholar 

  3. Ponomarenko, L. A. et al. Tunable metal-insulator transition in double-layer graphene heterostructures. Nature Phys. 7, 958–961 (2011).

    Article  CAS  Google Scholar 

  4. Britnell, L. et al. Field-effect tunneling transistor based on vertical graphene heterostructures. Science 335, 947–950 (2012).

    Article  CAS  Google Scholar 

  5. Yankowitz, M. et al. Emergence of superlattice Dirac points in graphene on hexagonal boron nitride. Nature Phys. 8, 382–386 (2012).

    Article  CAS  Google Scholar 

  6. Meyer, J. C. et al. The structure of suspended graphene sheets. Nature 446, 60–63 (2007).

    Article  CAS  Google Scholar 

  7. Gass, M. H. et al. Free-standing graphene at atomic resolution. Nature Nanotech. 3, 676–681 (2008).

    Article  CAS  Google Scholar 

  8. Ci, L. et al. Atomic layers of hybridized boron nitride and graphene domains. Nature Mater. 9, 430–435 (2010).

    Article  CAS  Google Scholar 

  9. Pan, C. T. et al. Nanoscale electron diffraction and plasmon spectroscopy of single- and few-layer boron nitride. Phys. Rev. B 85, 045440 (2012).

    Article  Google Scholar 

  10. Zhou, W. et al. Atomically localized plasmon enhancement in monolayer graphene. Nature Nanotech. 7, 161–165 (2012).

    Article  CAS  Google Scholar 

  11. Hashimoto, A. et al. Direct evidence for atomic defects in graphene layers. Nature 430, 870–873 (2004).

    Article  CAS  Google Scholar 

  12. Warner, J. H. et al. Structural transformations in graphene studied with high spatial and temporal resolution. Nature Nanotech. 4, 500–504 (2009).

    Article  CAS  Google Scholar 

  13. Robertson, A. W. et al. Atomic structure of interconnected few layer graphene domains. ACS Nano 5, 6610–6618 (2011).

    Article  CAS  Google Scholar 

  14. Meyer, J. C. et al. Experimental analysis of charge redistribution due to chemical bonding by high-resolution transmission electron microscopy. Nature Mater. 10, 209–215 (2011).

    Article  CAS  Google Scholar 

  15. Krivanek, O. L. et al. Atom-by-atom structural and chemical analysis by annular dark-field electron microscopy. Nature 464, 571–574 (2010).

    Article  CAS  Google Scholar 

  16. Suenaga, K. & Koshino, M. Atom-by-atom spectroscopy at graphene edge. Nature 468, 1088–1090 (2010).

    Article  CAS  Google Scholar 

  17. Zan, R. et al. Metal–graphene interaction studied via atomic resolution scanning transmission electron microscopy. Nano Lett. 11, 1087–1092 (2012).

    Article  Google Scholar 

  18. Lovejoy, T. C. et al. Single atom identification by energy dispersive x-ray spectroscopy. Appl. Phys. Lett. 100, 154101 (2012).

    Article  Google Scholar 

  19. Castro Neto, A. H., Guinea, F., Peres, N. M. R., Novoselov, K. S. & Geim, A. K. The electronic properties of graphene. Rev. Mod. Phys. 81, 109–162 (2009).

    Article  CAS  Google Scholar 

  20. Amet, F. et al. Tunneling spectroscopy of graphene–boron–nitride heterostructures. Phys. Rev. B 85, 073405 (2012).

    Article  Google Scholar 

  21. Lee, G. H. et al. Electron tunneling through atomically flat and ultrathin hexagonal boron nitride. Appl. Phys. Lett. 99, 243114 (2011).

    Article  Google Scholar 

  22. Britnell, L. et al. Atomically thin boron nitride: A tunneling barrier for graphene devices. Nano Lett. 12, 1707–1710 (2012).

    Article  CAS  Google Scholar 

  23. Dean, C. R. et al. Boron nitride substrates for high-quality graphene electronics. Nature Nanotech. 5, 722–726 (2010).

    Article  CAS  Google Scholar 

  24. Mayorov, A. S. et al. Micrometer-scale ballistic transport in encapsulated graphene at room temperature. Nano Lett. 11, 2396–2399 (2011).

    Article  CAS  Google Scholar 

  25. Min, H., Bistritzer, R., Su, J. J. & MacDonald, A. H. Room-temperature superfluidity in graphene bilayers. Phys. Rev. B 78, 121401 (2008).

    Article  Google Scholar 

  26. Giannuzzi, L. A. & Stevie, F. A. A review of focused ion beam milling techniques for TEM specimen preparation. Micron 30, 197–204 (1999).

    Article  Google Scholar 

  27. Langford, R. M. Focused ion beams techniques for nanomaterials characterization. Microscopy Res. Tech. 69, 538–549 (2006).

    Article  CAS  Google Scholar 

  28. Schaffer, M. et al. Sample preparation for atomic-resolution STEM at low voltages by FIB. Ultramicroscopy 114, 62–71 (2012).

    Article  CAS  Google Scholar 

  29. Rubanov, S. & Munroe, P. R. Investigation of the structure of damage layers in TEM samples prepared using a focused ion beam. J. Mater. Sci. Lett. 20, 1181–1183 (2001).

    Article  CAS  Google Scholar 

  30. Suenaga, K. et al. Synthesis of nanoparticles and nanotubes with well-separated layers of boron nitride and carbon. Science 278, 653–655 (1997).

    Article  CAS  Google Scholar 

  31. Katsnelson, M. I. & Geim, A. K. Electron scattering on microscopic corrugations in graphene. Phil. Trans. R. Soc. A 366, 195–204 (2008).

    Article  CAS  Google Scholar 

  32. Altshuler, B. L. & Aronov, A. G. Zero bias anomaly in tunnel resistance and electron–electron interaction. Solid State Commun. 30, 115–117 (1979).

    Article  CAS  Google Scholar 

Download references

Acknowledgements

This work was supported by the Engineering and Physical Sciences Research Council (UK), the Royal Society, the Office of Naval Research, the Air Force Office of Scientific Research, the Defense Threat Reduction Agency (US) and the Körber Foundation.

Author information

Authors and Affiliations

Authors

Contributions

S.J.H. and R.G. led the project. Devices were made by R.G. and R.J. with electrical characterization by L.A.P., D.C.E. and K.S.N. S.J.H. performed TEM imaging and analysis. A.G. operated the FIB and S.R. provided TEM instrumental support. L.B. performed AFM analysis. R.G., S.J.H. and A.K.G. wrote the paper. All authors carried out data analysis, participated in discussion of the results and commented on the manuscript.

Corresponding authors

Correspondence to S. J. Haigh or R. Gorbachev.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary Information

Supplementary Information (PDF 493 kb)

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Haigh, S., Gholinia, A., Jalil, R. et al. Cross-sectional imaging of individual layers and buried interfaces of graphene-based heterostructures and superlattices. Nature Mater 11, 764–767 (2012). https://doi.org/10.1038/nmat3386

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nmat3386

This article is cited by

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing