A standing molecule as a single-electron field emitter

Abstract

Scanning probe microscopy makes it possible to image and spectroscopically characterize nanoscale objects, and to manipulate1,2,3 and excite4,5,6,7,8 them; even time-resolved experiments are now routinely achieved9,10. This combination of capabilities has enabled proof-of-principle demonstrations of nanoscale devices, including logic operations based on molecular cascades11, a single-atom transistor12, a single-atom magnetic memory cell13 and a kilobyte atomic memory14. However, a key challenge is fabricating device structures that can overcome their attraction to the underlying surface and thus protrude from the two-dimensional flatlands of the surface. Here we demonstrate the fabrication of such a structure: we use the tip of a scanning probe microscope to lift a large planar aromatic molecule (3,4,9,10-perylenetetracarboxylic-dianhydride) into an upright, standing geometry on a pedestal of two metal (silver) adatoms. This atypical and surprisingly stable upright orientation of the single molecule, which under all known circumstances adsorbs flat on metals15,16, enables the system to function as a coherent single-electron field emitter. We anticipate that other metastable adsorbate configurations might also be accessible, thereby opening up the third dimension for the design of functional nanostructures on surfaces.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

Fig. 1: Creation of a standing molecule.
Fig. 2: Stability and geometry of the standing molecule.
Fig. 3: A standing molecule as a single-electron field emitter.

References

  1. 1.

    Eigler, D. M. & Schweizer, E. K. Positioning single atoms with a scanning tunnelling microscope. Nature 344, 524–526 (1990).

    Article  ADS  CAS  Google Scholar 

  2. 2.

    Ternes, M., Lutz, C. P., Hirjibehedin, C. F., Giessibl, F. J. & Heinrich, A. J. The force needed to move an atom on a surface. Science 319, 1066–1069 (2008).

    Article  PubMed  ADS  CAS  Google Scholar 

  3. 3.

    Wagner, C. et al. Scanning quantum dot microscopy. Phys. Rev. Lett. 115, 026101 (2015).

    Article  PubMed  ADS  CAS  Google Scholar 

  4. 4.

    Stipe, B. C., Rezaei, M. A. & Ho, W. Single-molecule vibrational spectroscopy and microscopy. Science 280, 1732–1735 (1998).

    Article  PubMed  ADS  CAS  Google Scholar 

  5. 5.

    Heinrich, A. J., Gupta, J. A., Lutz, C. P. & Eigler, D. M. Single-atom spin-flip spectroscopy. Science 306, 466–469 (2004).

    Article  PubMed  ADS  CAS  Google Scholar 

  6. 6.

    Müllegger, S. et al. Radio frequency scanning tunneling spectroscopy for single-molecule spin resonance. Phys. Rev. Lett. 113, 133001 (2014).

    Article  PubMed  ADS  CAS  Google Scholar 

  7. 7.

    Baumann, S. et al. Electron paramagnetic resonance of individual atoms on a surface. Science 350, 417–420 (2015).

    Article  PubMed  ADS  CAS  Google Scholar 

  8. 8.

    Esat, T. et al. A chemically driven quantum phase transition in a two-molecule Kondo system. Nat. Phys. 12, 867–873 (2016).

    Article  CAS  Google Scholar 

  9. 9.

    Loth, S., Etzkorn, M., Lutz, C. P., Eigler, D. M. & Heinrich, A. J. Measurement of fast electron spin relaxation times with atomic resolution. Science  329, 1628–1630 (2010).

    Article  PubMed  ADS  CAS  Google Scholar 

  10. 10.

    Saunus, C., Bindel, J. R., Pratzer, M. & Morgenstern, M. Versatile scanning tunneling microscopy with 120 ps time resolution. Appl. Phys. Lett. 102, 051601 (2013).

    Article  PubMed  ADS  CAS  Google Scholar 

  11. 11.

    Heinrich, A. J., Lutz, C. P., Gupta, J. A. & Eigler, D. M. Molecule cascades. Science  298, 1381–1387 (2002).

    Article  PubMed  ADS  CAS  Google Scholar 

  12. 12.

    Fuechsle, M. et al. A single-atom transistor. Nat. Nanotechnol. 7, 242–246 (2012).

    Article  PubMed  ADS  CAS  Google Scholar 

  13. 13.

    Donati, F. et al. Magnetic remanence in single atoms. Science  352, 318–321 (2016).

    Article  PubMed  ADS  CAS  Google Scholar 

  14. 14.

    Kalff, F. E. et al. A kilobyte rewritable atomic memory. Nat. Nanotechnol. 11, 926–929 (2016).

    Article  ADS  CAS  Google Scholar 

  15. 15.

    Witte, G. & Wöll, C. Growth of aromatic molecules on solid substrates for applications in organic electronics. J. Mater. Res. 19, 1889–1916 (2004).

    Article  ADS  CAS  Google Scholar 

  16. 16.

    Maurer, R. J. et al. Adsorption structures and energetics of molecules on metal surfaces: bridging experiment and theory. Prog. Surf. Sci. 91, 72–100 (2016).

    Article  ADS  CAS  Google Scholar 

  17. 17.

    Eremtchenko, M., Schaefer, J. A. & Tautz, F. S. Understanding and tuning the epitaxy of large aromatic adsorbates by molecular design. Nature 425, 602–605 (2003).

    Article  PubMed  ADS  CAS  Google Scholar 

  18. 18.

    Temirov, R., Soubatch, S., Luican, A. & Tautz, F. S. Free-electron-like dispersion in an organic monolayer film on a metal substrate. Nature 444, 350–353 (2006).

    Article  PubMed  ADS  CAS  Google Scholar 

  19. 19.

    Schuler, B. et al. Adsorption geometry determination of single molecules by atomic force microscopy. Phys. Rev. Lett. 111, 106103 (2013).

    Article  PubMed  ADS  CAS  Google Scholar 

  20. 20.

    Toher, C. et al. Electrical transport through a mechanically gated molecular wire. Phys. Rev. B 83, 155402 (2011).

    Article  ADS  CAS  Google Scholar 

  21. 21.

    Green, M. F. et al. Patterning a hydrogen-bonded molecular monolayer with a hand-controlled scanning probe microscope. Beilstein J. Nanotechnol. 5, 1926–1932 (2014).

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  22. 22.

    Kocić, N. et al. Periodic charging of individual molecules coupled to the motion of an atomic force microscopy tip. Nano Lett. 15, 4406–4411 (2015).

    Article  PubMed  ADS  CAS  Google Scholar 

  23. 23.

    Forbes, R. G. Physics of generalized Fowler–Nordheim-type equations. J. Vac. Sci. Technol. B 26, 788–793 (2008).

    Article  CAS  Google Scholar 

  24. 24.

    Gundlach, K. Zur Berechnung des Tunnelstroms durch eine trapezförmige Potentialstufe. Solid-State Electron. 9, 949–957 (1966).

    Article  ADS  Google Scholar 

  25. 25.

    Fink, H. W. Mono-atomic tips for scanning tunneling microscopy. IBM J. Res. Develop. 30, 460–465 (1986).

    Article  CAS  Google Scholar 

  26. 26.

    Oshima, C. et al. Young’s interference of electrons in field emission patterns. Phys. Rev. Lett. 88, 038301 (2002).

    Article  PubMed  ADS  CAS  Google Scholar 

  27. 27.

    Fève, G. et al. An on-demand coherent single electron source. Science 316, 1169–1172 (2007).

    Article  PubMed  ADS  CAS  Google Scholar 

  28. 28.

    Cocker, T. L., Peller, D., Yu, P., Repp, J. & Huber, R. Tracking the ultrafast motion of a single molecule by femtosecond orbital imaging. Nature 539, 263–267 (2016).

    Article  PubMed  PubMed Central  ADS  Google Scholar 

  29. 29.

    Longchamp, J. N. et al. Imaging proteins at the single-molecule level. Proc. Natl Acad. Sci. USA 114, 1474–1479 (2017).

    Article  PubMed  PubMed Central  ADS  CAS  Google Scholar 

  30. 30.

    Weiß, S. et al. Exploring three-dimensional orbital imaging with energy-dependent photoemission tomography. Nat. Commun. 6, 8287 (2015).

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  31. 31.

    Gross, L., Mohn, F., Moll, N., Liljeroth, P. & Meyer, G. The chemical structure of a molecule resolved by atomic force microscopy. Science 325, 1110–1114 (2009).

    Article  PubMed  ADS  CAS  Google Scholar 

  32. 32.

    Schmidt, M. W. et al. General atomic and molecular electronic structure system. J. Comput. Chem. 14, 1347–1363 (1993).

    Article  CAS  Google Scholar 

  33. 33.

    Weymouth, A. J., Hofmann, T. & Giessibl, F. J. Quantifying molecular stiffness and interaction with lateral force microscopy. Science 343, 1120–1122 (2014).

    Article  PubMed  ADS  CAS  Google Scholar 

  34. 34.

    Demuth, J. E., Christmann, K. & Sanda, P. N. The vibrations and structure of pyridine chemisorbed on Ag(111): the occurrence of a compressional phase transformation. Chem. Phys. Lett. 76, 201–206 (1980).

    Article  ADS  CAS  Google Scholar 

  35. 35.

    Lee, I., Son, S., Shin, T. & Hahn, J. R. Direct observation of the conformational transitions of single pyridine molecules on a Ag(110) surface induced by long-range repulsive intermolecular interactions. J. Chem. Phys. 146, 014706 (2017).

    Article  PubMed  ADS  CAS  Google Scholar 

  36. 36.

    Ulman, A. Formation and structure of self-assembled monolayers. Chem. Rev. 96, 1533–1554 (1996).

    Article  PubMed  CAS  Google Scholar 

  37. 37.

    Blyholder, G. Molecular orbital view of chemisorbed carbon monoxide. J. Phys. Chem. 68, 2772–2777 (1964).

    Article  CAS  Google Scholar 

  38. 38.

    Cai, Y., Guo, Y., Xu, X. & Jiang, B. First-principle investigation 3,4-ethylenedioxythiophene molecule adsorption on Cu(110)-(2 × 1)O surface. Surf. Sci. 665, 83–88 (2017).

    Article  ADS  CAS  Google Scholar 

  39. 39.

    Jasper-Tönnies, T. et al. Conductance of a freestanding conjugated molecular wire. Phys. Rev. Lett. 119, 066801 (2017).

    Article  PubMed  ADS  Google Scholar 

  40. 40.

    Gerhard, L. et al. An electrically actuated molecular toggle switch. Nat. Commun. 8, 14672 (2017).

    Article  PubMed  PubMed Central  ADS  Google Scholar 

  41. 41.

    Chelvayohan, M. & Mee, C. H. B. Work function measurements on (110), (100) and (111) surfaces of silver. J. Phys. C 15, 2305–2312 (1982).

    Article  ADS  CAS  Google Scholar 

Download references

Acknowledgements

We thank L. Kronik and S. Sarkar (Weizmann Institute of Science) and M. Rohlfing (Universität Münster) for performing DFT calculations of standing molecules (not reported here).

Reviewer information

Nature thanks T. Greber, A. Heinrich and the other anonymous reviewer(s) for their contribution to the peer review of this work.

Author information

Affiliations

Authors

Contributions

T.E., F.S.T. and R.T. conceived the research. T.E., N.F. and R.T. conducted the NC-AFM/STM experiments and analysed the resultant experimental data. T.E., R.T. and F.S.T. interpreted the data. T.E. carried out simulations and prepared the figures. T.E., R.T. and F.S.T. wrote the paper.

Corresponding author

Correspondence to F. Stefan Tautz.

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.

Extended data figures and tables

Extended Data Fig. 1 A standing NTCDA molecule.

a, Constant-current STM image of an NTCDA (1,4,5,8-naphthalenetetracarboxylic-dianhydride) molecule and two silver adatoms, recorded before the assembly of a NTCDA + 2Ag complex. b, AFM image of a standing NTCDA molecule, recorded at a tip height of z = 13.5 Å above the surface. c, Schematic side view of standing PTCDA and NTCDA molecules. The length difference of 4.2 Å between the two molecules corresponds well with the tip-height difference Δz = 17.5 Å − 13.5 Å = 4.0 Å between the AFM images of the standing PTCDA (see Fig. 1f) and NTCDA (b) molecules.

Extended Data Fig. 2 Two standing PTCDA molecules.

a, Constant-current STM image of two PTCDA + 2Ag complexes that were assembled in the same way as shown in Fig. 1b. b, AFM image of the standing molecules, recorded at tip height of z = 17.5 Å above the surface (left). One of the standing molecules is then moved closer to the other by the lateral manipulation procedure demonstrated in Extended Data Fig. 3a (right).

Extended Data Fig. 3 Manipulation of the standing molecule.

a, Lateral movement of the standing molecule by tip approach. The white cross in the AFM image on the left indicates the tip position during manipulation (V = 2 mV). b, Rotational movement of the standing molecule by a current pulse. The white cross in the AFM image on the left indicates the tip position during manipulation (z = 17.5 Å). The molecule jumps from a red (symmetric) to a black (asymmetric) position (see Methods). c, Toppling over the standing molecule to the surface by using a positive bias-voltage sweep. The white cross in the AFM image on the left indicates the tip position during manipulation (z = 17.5 Å). The constant-current STM image on the right shows the PTCDA + 2Ag complex after the toppling.

Extended Data Fig. 4 Determining the tilting stiffness of the standing molecule.

a, Approach along the y direction as defined in Fig. 2a, b. Parameters are d = 3.25 Å, l = 12.9 Å and 2a = 4.55 Å; d + l ≠ z, because the tip height z is measured from the centre of the uppermost surface layer, whereas l is measured from the centre of the two silver adatoms in the PTCDA + 2Ag complex. b, Approach along the x direction as defined in Fig. 2a, b. The sketch on the left shows a side view, whereas on the right a perspective view onto the top of the molecule is drawn. c, Left, best fit (green line) of the experimental F x (on x axis, red circles), obtained with the model in equation (8) and κ θ  = 630 zN m rad−1 (κ = 0.38 N m−1). Black data points display F y (on y axis), fitted with equation (4) (blue line). d, As in c, but for a simulated curve (green) with κ θ  = 20.0 aN m rad−1 (κ = 12.02 N m−1), which is too stiff to reproduce the experimental F x (red). e, As in c, but for a simulated curve (green) with κ θ  = 310 zN m rad−1 (κ = 0.19 N m−1), which is too soft. For a detailed discussion of this figure, see Methods. Tilt angles θeq and linear elongations xm are plotted in the middle and right panels in ce.

Extended Data Fig. 5 Orientation of the standing molecule.

The histogram (left) shows all evaluated orientations of standing PTCDA molecules on the Ag(111) surface. The angle is defined as in Fig. 2d and Extended Data Fig. 3b. In total, we evaluated the orientations of 128 standing PTCDA molecules. The possible orientations on the Ag(111) surface are illustrated on the right. Black and red symbols indicate the possible positions of one of the silver atoms at the surface contact, when the other sits in the centre. See also Fig. 2d and Methods.

Extended Data Fig. 6 The Ag(111) lattice.

Constant-current STM image of the atomically resolved Ag(111) surface. In all experiments, the Ag(111) lattice orientation was as shown in this image.

Extended Data Fig. 7 Field-emission images.

ac, Successive field-emission images (without the background) recorded at z = 73.5 Å and bias voltages of V = −24.00 V (a), V = −24.35 V (b) and V = −24.70 V (c).

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Esat, T., Friedrich, N., Tautz, F.S. et al. A standing molecule as a single-electron field emitter. Nature 558, 573–576 (2018). https://doi.org/10.1038/s41586-018-0223-y

Download citation

Further reading

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.

Search

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