Large-area single-crystal sheets of borophene on Cu(111) surfaces


Borophene, a theoretically proposed two-dimensional (2D) boron allotrope1,2,3, has attracted much attention4,5 as a candidate material platform for high-speed, transparent and flexible electronics6,7,8,9. It was recently synthesized, on Ag(111) substrates10,11, and studied by tunnelling and electron spectroscopy12. However, the exact crystal structure is still controversial, the nanometre-size single-crystal domains produced so far are too small for device fabrication and the structural tunability via substrate-dependent epitaxy is yet to be proven. We report on the synthesis of borophene monitored in situ by low-energy electron microscopy, diffraction and scanning tunnelling microscopy (STM) and modelled by ab initio theory. We resolved the crystal structure and phase diagram of borophene on Ag(111), but found that the domains remain nanoscale for all growth conditions. However, by growing borophene on Cu(111) surfaces, we obtained large single-crystal domains, up to 100 μm2 in size. The crystal structure is a novel triangular network with a concentration of hexagonal vacancies of η = 1/5. Our experimental data, together with first principles calculations, indicate charge-transfer coupling to the substrate without significant covalent bonding. Our work sets the stage for fabricating borophene-based devices and substantiates the idea of borophene as a model for development of artificial 2D materials.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Fig. 1: Structure of borophene grown on Ag(111) surfaces.
Fig. 2: Growth dynamics of the borophene on the Cu(111) surface.
Fig. 3: Domain structure of borophene on Cu(111) revealed by selected-area diffraction.
Fig. 4: The structure of borophene on Cu(111) as revealed by STM data and DFT simulations.
Fig. 5: Charge-transfer interaction between borophene and the Cu(111) surface.

Data availability

All the data generated and analysed during this study are included within this paper and the associated Supplementary Information.

Change history

  • 14 December 2018

    The links to the Supplementary Video files were missing; they have now been included.


  1. 1.

    Tang, H. & Ismail-Beigi, S. Novel precursors for boron nanotubes: the competition of two-center and three center bonding in boron sheets. Phys. Rev. Lett. 99, 115501 (2007).

    Article  Google Scholar 

  2. 2.

    Yang, X., Ding, Y. & Ni, J. Ab initio prediction of stable boron sheets and boron nanotubes: structure, stability and electronic properties. Phys. Rev. B 77, 041402(R) (2008).

    Article  Google Scholar 

  3. 3.

    Tang, H. & Ismail-Beigi, S. Self-doping in boron sheets from first principles: a route to structural design of metal boride nanostructures. Phys. Rev. B 80, 134113 (2009).

    Article  Google Scholar 

  4. 4.

    Mannix, A. J., Kiraly, B., Hersam, M. C. & Guisinger, N. P. Synthesis and chemistry of elemental 2D materials. Nat. Rev. Chem 1, 0014 (2017).

    CAS  Article  Google Scholar 

  5. 5.

    Mannix, A. J., Zhang, Z., Guisinger, N. P., Yakobson, B. I. & Hersam, M. C. Borophene as a prototype for synthetic 2D materials development. Nat. Nanotech. 13, 444–450 (2018).

    CAS  Article  Google Scholar 

  6. 6.

    Zhang, Z. H., Penev, E. S. & Yakobson, B. I. Polyphony in B flat. Nat. Chem. 8, 525–527 (2016).

    CAS  Article  Google Scholar 

  7. 7.

    Penev, E. S., Bhowmick, S., Sadrzadeh, A. & Yakobson, B. I. Polymorphism of two-dimensional boron. Nano Lett. 12, 2441–2445 (2012).

    CAS  Article  Google Scholar 

  8. 8.

    Wu, X. et al. Two-dimensional boron monolayer sheets. ACS Nano 6, 7443–7453 (2012).

    CAS  Article  Google Scholar 

  9. 9.

    Zhang, Z., Yang, Y., Penev, E. S. & Yakobson, B. I. Elasticity, flexibility and ideal strength of borophenes. Adv. Func. Mat. 27, 1605059 (2017).

    Article  Google Scholar 

  10. 10.

    Mannix, A. J. et al. Synthesis of borophenes: anisotropic, two-dimensional boron polymorphs. Science 350, 1513–1516 (2015).

    CAS  Article  Google Scholar 

  11. 11.

    Feng, B. et al. Experimental realization of two-dimensional boron sheets. Nat. Chem. 8, 563–568 (2016).

    CAS  Article  Google Scholar 

  12. 12.

    Feng, B. J. et al. Direct evidence of metallic bands in a monolayer boron sheet. Phys. Rev. B 94, 041408 (2016).

    Article  Google Scholar 

  13. 13.

    Zhang, Z. H., Yang, Y., Gao, G. Y. & Yakobson, B. I. Two-dimensional boron monolayers mediated by metal substrates. Angew. Chem. Int. Ed. 54, 13022–13026 (2015).

    CAS  Article  Google Scholar 

  14. 14.

    Penev, E. S., Kutana, A. & Yakobson, B. I. Can two-dimensional boron superconduct? Nano Lett. 16, 2522–2526 (2016).

    CAS  Article  Google Scholar 

  15. 15.

    Feng, B. et al. Dirac fermions in borophene. Phys. Rev. Lett. 118, 096401 (2017).

    Article  Google Scholar 

  16. 16.

    Volovik, G. E. From standard model of particle physics to room-temperature superconductivity. Phys. Scr. T164, 014014 (2015).

    Article  Google Scholar 

  17. 17.

    Bauer, E. Low energy electron microscopy. Rep. Progr. Phys. 57, 895–938 (1994).

    CAS  Article  Google Scholar 

  18. 18.

    Hannon, J. B. & Tromp, R. M. Low-energy microscopy of surface phase transitions. Annu. Rev. Mater. Res. 33, 263 (2003).

    CAS  Article  Google Scholar 

  19. 19.

    Suter, P., Sadowski, J. T. & Sutter, E. Graphene on Pt(111): growth and substrate interaction. Phys. Rev. B 80, 245411 (2009).

    Article  Google Scholar 

  20. 20.

    Altman, M. S. Trends in low energy electron microscopy. J. Phys. Condens. Matter 22, 084017 (2010).

    CAS  Article  Google Scholar 

  21. 21.

    Giessibl, F. J. High-speed force sensor for force microscopy and profilometry utilizing a quartz tuning fork. Appl. Phys. Lett. 73, 3956–3958 (1998).

    CAS  Article  Google Scholar 

  22. 22.

    Gross, L. et al. High-resolution molecular orbital imaging using a p-wave STM tip. Phys. Rev. Lett. 107, 086101 (2011).

    Article  Google Scholar 

  23. 23.

    Hapala, P. et al. Mechanism of high resolution STM/AFM imaging with functionalized tips. Phys. Rev. B 90, 085421 (2014).

    Article  Google Scholar 

  24. 24.

    Gianozzi, P. et al. Quantum Espresso: a modular and open source software project for quantum simulations of materials. J. Phys. Condens. Matter 21, 395502 (2009).

    Article  Google Scholar 

  25. 25.

    Tersoff, J. & Hamann, D. R. Theory and application for the scanning tunneling microscope. Phys. Rev. Lett. 50, 1998 (1983).

    CAS  Article  Google Scholar 

  26. 26.

    Chen, C. J. Tunneling matrix elements in three dimensional space: the derivative rule and the sum rule. Phys. Rev. B 42, 8841 (1990).

    CAS  Article  Google Scholar 

  27. 27.

    Liu, H. S., Gao, J. F. & Zhao, J. J. From boron cluster to two-dimensional boron sheet on Cu(111) surface: growth mechanism and hole formation. Sci. Rep. 3, 3238 (2013).

    Article  Google Scholar 

  28. 28.

    Galeev, T. R. et al. Deciphering the mystery of hexagon holes in an all boron graphene α-sheet. Phys. Chem. Chem. Phys. 13, 11575–11578 (2011).

    CAS  Article  Google Scholar 

  29. 29.

    Zhang, Z. et al. Substrate induced nanoscale undulations of borophene on silver. Nano Lett. 16, 6622–6627 (2016).

    CAS  Article  Google Scholar 

  30. 30.

    Liu, X., Zhang, Z., Wang, L., Yakobson, B. I. & Hersam, M. C. Intermixing and periodic self-assembly of borophene line defects. Nat. Mater. 17, 783–788 (2018).

    CAS  Article  Google Scholar 

Download references


This research was supported by the US Department of Energy, Basic Energy Sciences, Materials Sciences and Engineering Division. R.W. and A.G. are supported by the Gordon and Betty Moore Foundation’s EPiQS Initiative through grant GBMF4410. I.K.D. acknowledges the support of a BNL Gertrude and Maurice Goldhaber Distinguished Fellowship. This research used resources of the Center for Functional Nanomaterials, which is a US DOE Office of Science Facility, at Brookhaven National Laboratory under contract no. DE-SC0012704. S.E. is supported by the National Science Foundation Graduate Research Fellowship through grant DGE-1122492. S.E and S.I.-B. thank the computing resources provided by the staff of the Yale University Faculty of Arts and Sciences High Performance Computing Center as well as NSF XSEDE resources via grant TG-MCA08X007.

Author information




R.W. took and analysed the experimental LEEM, LEED, XPS and AFM data with help from A.G. I.K.D. and P.Z. acquired the low-temperature STM data and analysed them with help from R.W. and A.G., S.E. and S.I.-B. performed the ab initio calculations and analysed the results. I.B. conceived and supervised the project. A.G. wrote the manuscript with contributions from all the authors.

Corresponding author

Correspondence to Adrian Gozar.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Supplementary Information

Supplementary Video 1

B-Cu111 Film growth

Supplementary Video 2

B-Cu111 Faceted islands

Supplementary Video 3

B-Cu111 Miscibility

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Wu, R., Drozdov, I.K., Eltinge, S. et al. Large-area single-crystal sheets of borophene on Cu(111) surfaces. Nature Nanotech 14, 44–49 (2019).

Download citation

Further reading