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Dirac-point photocurrents due to the photothermoelectric effect in non-uniform graphene devices

Nature Nanotechnology volume 15, pages 241–243 (2020)Cite this article

Matters Arising to this article was published on 17 February 2020

The Original Article was published on 17 December 2018

arising from Jarillo-Herrero et al. Nature Nanotechnology https://doi.org/10.1038/s41565-018-0323-8 (2018).

Ma et al.1 recently reported a strong photocurrent associated with charge neutrality in graphene devices with non-uniform geometries, which they interpreted as an intrinsic Dirac-point (IDP) photoresponse enhanced by the momentum non-relaxing nature of electron–electron collisions at charge neutrality. Here we argue that gradients in charge carrier density give rise to a photothermoelectric effect (PTE) that is strongly peaked around charge neutrality, that is at p–n junctions, and such p–n junctions naturally arise at the edges of graphene devices due to fringing capacitance. Using known parameters, the PTE effect in the presence of charge density gradients predicts the sign, spatial distribution, gate voltage dependence and temperature dependence of the photoresponse in non-uniform graphene devices, including predicting the observed sign change of the signal away from charge neutrality and the non-monotonic temperature dependence, neither of which is explained by IDP photocurrents in graphene. We propose future experiments that may disentangle the contributions of PTE and intrinsic photocurrent in graphene devices.

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Fig. 1: Calculated charge carrier density (colour scale) induced by a back gate in a cross-shaped graphene device with arms of width 800 nm over a 300 nm SiO2 gate dielectric.
Fig. 2: Comparison of PTE model and experiment.

Data availability

The datasets generated during and/or analysed during the current study are available from the corresponding author on reasonable request.

References

  1. Ma, Q. et al. Giant intrinsic photoresponse in pristine graphene. Nat. Nanotechnol. 14, 145–150 (2019).

    Article  CAS  Google Scholar 

  2. Schneider, M. V. Microstrip lines for microwave integrated circuits. Bell Syst. Tech. J. 48, 1421–1444 (1969).

    Article  CAS  Google Scholar 

  3. Song, J. C. W. & Levitov, L. S. Shockley−Ramo theorem and long-range photocurrent response in gapless materials. Phys. Rev. B 90, 075415 (2014).

    Article  Google Scholar 

  4. Gabor, N. M. et al. Hot carrier-assisted intrinsic photoresponse in graphene. Science 334, 648–652 (2011).

    Article  CAS  Google Scholar 

  5. Zuev, Y. M., Chang, W. & Kim, P. Thermoelectric and magnetothermoelectric transport measurements of graphene. Phys. Rev. Lett. 102, 096807 (2009).

    Article  Google Scholar 

  6. Ma, Q. et al. Competing channels for hot-electron cooling in graphene. Phys. Rev. Lett. 112, 247401 (2014).

    Article  Google Scholar 

Download references

Acknowledgements

We acknowledge support of the ARC Centre of Excellence FLEET (grant no. CE170100039).

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Authors and Affiliations

  1. ARC Centre of Excellence in Future Low Energy Electronic Technologies, Monash University, Monash, Victoria, Australia

    Michael S. Fuhrer & Nikhil V. Medhekar

  2. School of Physics and Astronomy, Monash University, Monash, Victoria, Australia

    Michael S. Fuhrer

  3. Department of Materials Science and Engineering, Monash University, Monash, Victoria, Australia

    Nikhil V. Medhekar

Authors
  1. Michael S. Fuhrer
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  2. Nikhil V. Medhekar
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Contributions

M.S.F. conceived this work and carried out the simulations in Fig. 2. N.V.M. carried out the simulation in Fig. 1. M.S.F. and N.V.M. wrote the manuscript together.

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Correspondence to Michael S. Fuhrer.

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Fuhrer, M.S., Medhekar, N.V. Dirac-point photocurrents due to the photothermoelectric effect in non-uniform graphene devices. Nat. Nanotechnol. 15, 241–243 (2020). https://doi.org/10.1038/s41565-020-0637-1

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