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Monitoring dopants by Raman scattering in an electrochemically top-gated graphene transistor

Abstract

The recent discovery of graphene1,2,3 has led to many advances in two-dimensional physics and devices4,5. The graphene devices fabricated so far have relied on SiO2 back gating1,2,3. Electrochemical top gating is widely used for polymer transistors6,7, and has also been successfully applied to carbon nanotubes8,9. Here we demonstrate a top-gated graphene transistor that is able to reach doping levels of up to 5×1013 cm−2, which is much higher than those previously reported. Such high doping levels are possible because the nanometre-thick Debye layer8,10 in the solid polymer electrolyte gate provides a much higher gate capacitance than the commonly used SiO2 back gate, which is usually about 300 nm thick11. In situ Raman measurements monitor the doping. The G peak stiffens and sharpens for both electron and hole doping, but the 2D peak shows a different response to holes and electrons. The ratio of the intensities of the G and 2D peaks shows a strong dependence on doping, making it a sensitive parameter to monitor the doping.

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Figure 1: Electrochemically top-gated graphene transistor.
Figure 2: Conductivity minimum in graphene.
Figure 3: Raman spectra of graphene as a function of gate voltage.
Figure 4: The influence of hole and electron doping on the 2D and G peaks.

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References

  1. Novoselov, K. S. et al. Electric field effect in atomically thin carbon films. Science 306, 666–669 (2004).

    Article  CAS  Google Scholar 

  2. Novoselov, K. S. et al. Two-dimensional gas of massless Dirac fermions in graphene. Nature 438, 197–200 (2005).

    Article  CAS  Google Scholar 

  3. Zhang, Y., Tan, Y.-W., Stormer, H. L. & Kim, P. Experimental observation of the quantum Hall effect and Berryś phase in graphene. Nature 438, 201–204 (2005).

    Article  CAS  Google Scholar 

  4. Lemme, M.C., Echtermeyer, T.J., Baus, M. & Kurz, H. A Graphene field-effect device. IEEE Electron. Device Lett. 28, 282–284 (2007).

    Article  CAS  Google Scholar 

  5. Han, M. Y., Ozyilmaz, B., Zhang, Y. & Kim, P. Energy band-gap engineering of graphene nanoribbons. Phys. Rev. Lett. 98, 206805 (2007).

    Article  Google Scholar 

  6. Sirringhaus, H. et al. High-resolution inkjet printing of all-polymer transistor circuits. Science 290, 2123–2126 (2000).

    Article  CAS  Google Scholar 

  7. Dhoot, A. S. et al. Beyond the metal–insulator transition in polymer electrolyte gated polymer field-effect transistors. Proc. Natl Acad. Sci. USA 103, 11834–11837 (2006).

    Article  CAS  Google Scholar 

  8. Nguyen, K. T., Gaur, A. & Shim, M. Fano lineshape and phonon softening in single isolated metallic carbon nanotubes. Phys. Rev. Lett. 98, 145504 (2007).

    Article  Google Scholar 

  9. Das, A. et al. Doping in carbon nanotubes probed by raman and transport measurements. Phys. Phys. Lett. 99, 136803 (2007).

    Article  Google Scholar 

  10. Lu, C., Fu, Q., Huang, S. & Liu, J. Polymer electrolyte-gated carbon nanotube field-effect transistor. Nano Lett. 4, 623–627 (2004).

    Article  CAS  Google Scholar 

  11. Geim, A. K. & Novoselov, K. S. The rise of graphene. Nature Mater. 6, 183–191 (2007).

    Article  CAS  Google Scholar 

  12. Tan, Y.-W. et al. Measurement of scattering rate and minimum conductivity in graphene. Phys. Rev. Lett. 99, 246803 (2007).

    Article  Google Scholar 

  13. Morozov, S. V. et al. Giant intrinsic carrier mobilities in graphene and its bilayer. Phys. Rev. Lett. 100, 016602 (2008).

    Article  CAS  Google Scholar 

  14. Huard, B. et al. Transport measurements across a tunable potential barrier in graphene. Phys. Rev. Lett. 98, 236803 (2007).

    Article  CAS  Google Scholar 

  15. Ferrari, A. C. et al. Raman spectrum of graphene and graphene layers. Phys. Rev. Lett. 97, 187401 (2006).

    Article  CAS  Google Scholar 

  16. Pisana, S. et al. Breakdown of the adiabatic Born–Oppenheimer approximation in graphene. Nature Mater. 6, 198–201 (2007).

    Article  CAS  Google Scholar 

  17. Yan, J., Zhang, Y., Kim, P. & Pinczuk, A. Electric field effect tuning of electron–phonon coupling in graphene. Phys. Rev. Lett. 98, 166802 (2007).

    Article  Google Scholar 

  18. Casiraghi, C., Pisana, S., Novoselov K. S., Geim A. K. & Ferrari A. C. Raman fingerprint of charged impurities in graphene. Appl. Phys. Lett. 91, 233108 (2007).

    Article  Google Scholar 

  19. Stampfer, C. et al. Raman imaging of charged domains in graphene on SiO2 . Appl. Phys. Lett. 91, 241907 (2007).

    Article  Google Scholar 

  20. Thomsen, C. & Reich, S. Double resonant Raman scattering in graphite. Phys. Rev. Lett. 85, 5214–5217 (2000).

    Article  CAS  Google Scholar 

  21. Piscanec, S., Lazzeri, M., Mauri, F., Ferrari, A. & Robertson, J. Kohn anomalies and electron–phonon interactions in graphite. Phys. Rev. Lett. 93, 185503 (2004).

    Article  CAS  Google Scholar 

  22. Piscanec, S., Lazzeri, M., Robertson, J., Ferrari, A. C. & Mauri, F. Optical phonons in carbon nanotubes: Kohn anomalies, Peierls distortions, and dynamic effects. Phys. Rev. B 75, 035427 (2007).

    Article  Google Scholar 

  23. Lazzeri, M., Piscanec, S., Mauri, F., Ferrari, A. C. & Robertson, J. Phonon linewidths and electron–phonon coupling in graphite and nanotubes. Phys. Rev. B 73, 155426 (2006).

    Google Scholar 

  24. Tsang, J. C., Freitag, M., Perebeinos, V., Liu, J. & Avouris, P. H. Doping and phonon renormalization in carbon nanotubes. Nature Nanotech. 2, 725–730 (2007).

    Article  CAS  Google Scholar 

  25. Gupta, A., Chen, G., Joshi, P., Tadigadapa, S. & Eklund, P. C. Raman scattering from high-frequency phonons in supported n-graphene layer films. Nano Lett. 6, 2667–2673 (2006).

    Article  CAS  Google Scholar 

  26. Graf, D. et al. Spatially resolved Raman spectroscopy of single- and few-layer graphene. Nano Lett. 7, 238–242 (2007).

    Article  CAS  Google Scholar 

  27. Lazzeri, M. & Mauri, F. Nonadiabatic Kohn anomaly in a doped graphene monolayer. Phys. Rev. Lett. 97, 266407 (2006).

    Article  Google Scholar 

  28. Maultzsch, J., Reich, S. & Thomsen, C. Chirality-selective Raman scattering of the D mode in carbon nanotubes. Phys. Rev. B 61, 121407 (2001).

    Article  Google Scholar 

  29. Pietronero, L. & Strassler, S. Bond-length change as a tool to determine charge transfer and electron–phonon coupling in graphite intercalation compounds. Phys. Rev. Lett. 47, 593–596 (1981).

    Article  CAS  Google Scholar 

  30. Salomon, M., Xu, M., Eyring, E. M. & Petrucci, S. Molecular structure and dynamics of LiC104–polyethylene oxide-400 (dimethyl ether and diglycol systems) at 25 °C. J. Phys. Chem. 98, 8234–8244 (1994).

    Article  CAS  Google Scholar 

  31. Boyd, R. H. The dielectric constant of lamellar semicrystalline polymers. J. Polym. Sci. Polym. Phys. Ed. 21, 505–514 (1983).

    Article  CAS  Google Scholar 

  32. Perdew, P., Burke, K. & Ernzerhof, M. Generalized gradient approximation made simple. Phys. Rev. Lett. 77, 3865–3868 (1996).

    Article  CAS  Google Scholar 

Download references

Acknowledgements

S.P. acknowledges funding from Pembroke College and the Maudslay Society. A.C.F. acknowledges funding from the Royal Society and Leverhulme Trust. A.K.S. thanks the Department of Science and Technology, India, for financial support.

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Correspondence to A. C. Ferrari or A. K. Sood.

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Das, A., Pisana, S., Chakraborty, B. et al. Monitoring dopants by Raman scattering in an electrochemically top-gated graphene transistor. Nature Nanotech 3, 210–215 (2008). https://doi.org/10.1038/nnano.2008.67

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