Real-space imaging of transient carrier dynamics by nanoscale pump–probe microscopy

Nature Photonics volume 4, pages869–874(2010)Cite this article

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Abstract

Smaller and faster are key concepts underlying the progress of current nanoscience and nanotechnology. The development of a method of exploring the transient carrier dynamics in organized nanostructures with pinpoint accuracy is therefore highly desirable. Here, we present a new microscopy that enables real-space measurement of the spatial variation of ultrafast dynamics. It is a pulse-laser-combined scanning tunnelling microscopy with a novel delay-time modulation method based on a pulse-picking technique. A non-equilibrium carrier distribution is generated with ultrashort laser pulses, and its relaxation processes are observed by scanning tunnelling microscopy using a pump–probe technique. We have directly analysed the recombination of excited carriers via the gap states associated with a cobalt nanoparticle/GaAs structure in real space. Through the site dependence of the decay time on the tunnelling current injection from the scanning tunnelling microscopy tip, the hole capture rate at the gap states has been imaged on the nanoscale for the first time.

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Figure 1: Schematics of the microscopy system and its probe mechanism.
Figure 2: Carrier dynamics over a wide range of timescales measured using the developed microscopy.
Figure 3: Bulk-side and surface-side carrier decay reflected in ΔI(td).
Figure 4: Carrier recombination via cobalt nanoparticle/GaAs gap states.
Figure 5: Real-space analysis of the hole capture rate at cobalt nanoparticle/GaAs gap states.

References

  1. 1

    Shinada, T., Okamoto, S., Kobayashi, T. & Ohdomari, I. Enhancing semiconductor device performance using ordered dopant arrays. Nature 437, 1128–1131 (2005).

    ADS  Article  Google Scholar 

  2. 2

    Shah, J. Ultrafast Spectroscopy of Semiconductors and Semiconductor Nanostructures (Springer, 1999).

    Google Scholar 

  3. 3

    Othonos, A. Probing ultrafast carrier and phonon dynamics in semiconductors. J. Appl. Phys. 83, 1789–1830 (1998).

    ADS  Article  Google Scholar 

  4. 4

    Binning, G., Rohrer, H., Gerber, Ch. & Weibel, E. Surface studies by scanning tunneling microscopy. Phys. Rev. Lett. 49, 57–61 (1982).

    ADS  Article  Google Scholar 

  5. 5

    Crommie, M. F., Lutz, C. P. & Eigler, D. M. Confinement of electrons to quantum corrals on a metal surface. Science 262, 218–220 (1993).

    ADS  Article  Google Scholar 

  6. 6

    Wiesendanger, R. (ed.) Scanning Probe Microscopy and Spectroscopy: Methods and Applications (Cambridge Univ. Press, 1994).

    Google Scholar 

  7. 7

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

    ADS  Article  Google Scholar 

  8. 8

    Lee, J. et al. Bandgap modulation of carbon nanotubes by encapsulated metallofullerenes. Nature 415, 1005–1008 (2002).

    ADS  Article  Google Scholar 

  9. 9

    Yoshida, S. et al. Microscopic basis for the mechanism of carrier dynamics in an operating p–n junction examined by using light-modulated scanning tunneling spectroscopy. Phys. Rev. Lett. 98, 026802 (2007).

    ADS  Article  Google Scholar 

  10. 10

    Hamers, R. J. & Cahill, D. G. Ultrafast time resolution in scanned probe microscopies. Appl. Phys. Lett. 57, 2021–2033 (1990).

    ADS  Article  Google Scholar 

  11. 11

    Nunes, G. Jr & Freeman, M. R. Picosecond resolution in scanning tunneling microscopy. Science 262, 1029–1032 (1993).

    ADS  Article  Google Scholar 

  12. 12

    Weiss, S., Ogletree, D. F., Botkin, D., Salmeron, M. & Chemla, D. S. Ultrafast scanning probe microscopy. Appl. Phys. Lett. 63, 2567–2569 (1993).

    ADS  Article  Google Scholar 

  13. 13

    Botkin, D. et al. Advances in ultrafast scanning tunneling microscopy. Appl. Phys. Lett. 69, 1321–1323 (1996).

    ADS  Article  Google Scholar 

  14. 14

    Groeneveld, R. H. M. & van Kempen, H. The capacitive origin of the picosecond electrical transients detected by a photoconductively gated scanning tunneling microscope. Appl. Phys. Lett. 69, 2294–2296 (1996).

    ADS  Article  Google Scholar 

  15. 15

    Pfeiffer, W. et al. Photoelectron emission in femtosecond laser assisted scanning tunneling microscopy. Appl. Phys. B 64, 265–268 (1997).

    ADS  Article  Google Scholar 

  16. 16

    Keil, U. D., Jensen, J. R. & Hvam, J. M. Transient measurements with an ultrafast scanning tunneling microscope. Appl. Phys. Lett. 72, 1644–1646 (1998).

    ADS  Article  Google Scholar 

  17. 17

    Khusnatdinov, N. N., Nagle, T. J. & Nunes, G Jr. Ultrafast scanning tunneling microscopy with 1 nm resolution. Appl. Phys. Lett. 77, 4434–4436 (2000).

    ADS  Article  Google Scholar 

  18. 18

    Grafström, S. Photoassisted scanning tunneling microscopy. J. Appl. Phys. 91, 1717–1753 (2002).

    ADS  Article  Google Scholar 

  19. 19

    Takeuchi, O. et al. Probing subpicosecond dynamics using pulsed laser combined scanning tunneling microscopy. Appl. Phys. Lett. 85, 3268–3270 (2004).

    ADS  Article  Google Scholar 

  20. 20

    Terada, Y. et al. Ultrafast photoinduced carrier dynamics in GaNAs probed using femtosecond time-resolved scanning tunneling microscopy. Nanotechnology 18, 044028 (2007).

    ADS  Article  Google Scholar 

  21. 21

    Kronik, L. & Shapira, Y. Surface photovoltage phenomena: theory, experiment and applications. Surf. Sci. Rep. 37, 1–206 (1999).

    ADS  Article  Google Scholar 

  22. 22

    Campbell, C. T. Ultrathin metal films and particles on oxide surfaces: structural, electronic and chemisorptive properties. Surf. Sci. Rep. 27, 1–111 (1997).

    ADS  Article  Google Scholar 

  23. 23

    Nilius, N., Wallis, T. & Ho, W. Development of one-dimensional band structure in artificial gold chains. Science 297, 1853–1856 (2002).

    ADS  Article  Google Scholar 

  24. 24

    Firt, P., Stroscio, J., Dragoset, R., Pierce, D. & Celotta, R. Metallicity and gap states in tunneling to Fe clusters on GaAs(100). Phys. Rev. Lett. 63, 1416–1419 (1989).

    ADS  Article  Google Scholar 

  25. 25

    Sze, S. M. Physics of Semiconductor Devices (John Wiley, 1981).

    Google Scholar 

  26. 26

    Schockley, W. & Read, W. T. Jr. Statics of the recombinations of holes and electrons. Phys. Rev. Lett. 87, 835–842 (1952).

    ADS  Google Scholar 

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Acknowledgements

The authors thank Y. Hirayama of Tohoku University in Japan for stimulating discussions.

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Affiliations

  1. Institute of Applied Physics, CREST-JST, University of Tsukuba, Tsukuba, 307-8573, Japan

    Yasuhiko Terada, Shoji Yoshida, Osamu Takeuchi & Hidemi Shigekawa

Authors
  1. Yasuhiko Terada
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  2. Shoji Yoshida
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  3. Osamu Takeuchi
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  4. Hidemi Shigekawa
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Contributions

Y.T. performed the SPPX-STM experiment and data analysis. S.Y. assisted in the SPPX-STM experiment and laser operation. O.T. provided technical and theoretical advice. H.S. organized and supervised the project and edited the paper. All authors carried out extensive analysis of the results.

Corresponding author

Correspondence to Hidemi Shigekawa.

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The authors declare no competing financial interests.

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Terada, Y., Yoshida, S., Takeuchi, O. et al. Real-space imaging of transient carrier dynamics by nanoscale pump–probe microscopy. Nature Photon 4, 869–874 (2010). https://doi.org/10.1038/nphoton.2010.235

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