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.
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References
Novoselov, K. S. et al. Two-dimensional atomic crystals. Proc. Natl Acad. Sci. USA 102, 10451–10453 (2005).
Wang, H. et al. BN/Graphene/BN transistors for RF applications. IEEE Electron Device Lett. 32, 1209–1211 (2011).
Ponomarenko, L. A. et al. Tunable metal-insulator transition in double-layer graphene heterostructures. Nature Phys. 7, 958–961 (2011).
Britnell, L. et al. Field-effect tunneling transistor based on vertical graphene heterostructures. Science 335, 947–950 (2012).
Yankowitz, M. et al. Emergence of superlattice Dirac points in graphene on hexagonal boron nitride. Nature Phys. 8, 382–386 (2012).
Meyer, J. C. et al. The structure of suspended graphene sheets. Nature 446, 60–63 (2007).
Gass, M. H. et al. Free-standing graphene at atomic resolution. Nature Nanotech. 3, 676–681 (2008).
Ci, L. et al. Atomic layers of hybridized boron nitride and graphene domains. Nature Mater. 9, 430–435 (2010).
Pan, C. T. et al. Nanoscale electron diffraction and plasmon spectroscopy of single- and few-layer boron nitride. Phys. Rev. B 85, 045440 (2012).
Zhou, W. et al. Atomically localized plasmon enhancement in monolayer graphene. Nature Nanotech. 7, 161–165 (2012).
Hashimoto, A. et al. Direct evidence for atomic defects in graphene layers. Nature 430, 870–873 (2004).
Warner, J. H. et al. Structural transformations in graphene studied with high spatial and temporal resolution. Nature Nanotech. 4, 500–504 (2009).
Robertson, A. W. et al. Atomic structure of interconnected few layer graphene domains. ACS Nano 5, 6610–6618 (2011).
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).
Krivanek, O. L. et al. Atom-by-atom structural and chemical analysis by annular dark-field electron microscopy. Nature 464, 571–574 (2010).
Suenaga, K. & Koshino, M. Atom-by-atom spectroscopy at graphene edge. Nature 468, 1088–1090 (2010).
Zan, R. et al. Metal–graphene interaction studied via atomic resolution scanning transmission electron microscopy. Nano Lett. 11, 1087–1092 (2012).
Lovejoy, T. C. et al. Single atom identification by energy dispersive x-ray spectroscopy. Appl. Phys. Lett. 100, 154101 (2012).
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).
Amet, F. et al. Tunneling spectroscopy of graphene–boron–nitride heterostructures. Phys. Rev. B 85, 073405 (2012).
Lee, G. H. et al. Electron tunneling through atomically flat and ultrathin hexagonal boron nitride. Appl. Phys. Lett. 99, 243114 (2011).
Britnell, L. et al. Atomically thin boron nitride: A tunneling barrier for graphene devices. Nano Lett. 12, 1707–1710 (2012).
Dean, C. R. et al. Boron nitride substrates for high-quality graphene electronics. Nature Nanotech. 5, 722–726 (2010).
Mayorov, A. S. et al. Micrometer-scale ballistic transport in encapsulated graphene at room temperature. Nano Lett. 11, 2396–2399 (2011).
Min, H., Bistritzer, R., Su, J. J. & MacDonald, A. H. Room-temperature superfluidity in graphene bilayers. Phys. Rev. B 78, 121401 (2008).
Giannuzzi, L. A. & Stevie, F. A. A review of focused ion beam milling techniques for TEM specimen preparation. Micron 30, 197–204 (1999).
Langford, R. M. Focused ion beams techniques for nanomaterials characterization. Microscopy Res. Tech. 69, 538–549 (2006).
Schaffer, M. et al. Sample preparation for atomic-resolution STEM at low voltages by FIB. Ultramicroscopy 114, 62–71 (2012).
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).
Suenaga, K. et al. Synthesis of nanoparticles and nanotubes with well-separated layers of boron nitride and carbon. Science 278, 653–655 (1997).
Katsnelson, M. I. & Geim, A. K. Electron scattering on microscopic corrugations in graphene. Phil. Trans. R. Soc. A 366, 195–204 (2008).
Altshuler, B. L. & Aronov, A. G. Zero bias anomaly in tunnel resistance and electron–electron interaction. Solid State Commun. 30, 115–117 (1979).
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.
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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.
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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
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DOI: https://doi.org/10.1038/nmat3386
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