Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Graphene–MoS2 hybrid structures for multifunctional photoresponsive memory devices

Abstract

Combining the electronic properties of graphene1,2 and molybdenum disulphide (MoS2)3,4,5,6 in hybrid heterostructures offers the possibility to create devices with various functionalities. Electronic logic and memory devices have already been constructed from graphene–MoS2 hybrids7,8, but they do not make use of the photosensitivity of MoS2, which arises from its optical-range bandgap9. Here, we demonstrate that graphene-on-MoS2 binary heterostructures display remarkable dual optoelectronic functionality, including highly sensitive photodetection and gate-tunable persistent photoconductivity. The responsivity of the hybrids was found to be nearly 1 × 1010 A W−1 at 130 K and 5 × 108 A W−1 at room temperature, making them the most sensitive graphene-based photodetectors. When subjected to time-dependent photoillumination, the hybrids could also function as a rewritable optoelectronic switch or memory, where the persistent state shows almost no relaxation or decay within experimental timescales, indicating near-perfect charge retention. These effects can be quantitatively explained by gate-tunable charge exchange between the graphene and MoS2 layers, and may lead to new graphene-based optoelectronic devices that are naturally scalable for large-area applications at room temperature.

This is a preview of subscription content, access via your institution

Relevant articles

Open Access articles citing this article.

Access options

Buy article

Get time limited or full article access on ReadCube.

$32.00

All prices are NET prices.

Figure 1: Device and optoelectronic response.
Figure 2: Photoresponsivity of graphene–MoS2 hybrid.
Figure 3: Gate- and intensity-dependent switching and relaxation.
Figure 4: Persistent photoconductivity mechanism.

References

  1. Novoselov, K. S. et al. A roadmap for graphene. Nature 490, 192–200 (2012).

    CAS  Article  Google Scholar 

  2. Dean, C. et al. Boron nitride substrates for high-quality graphene electronics. Nature Nanotech. 5, 722–726 (2010).

    CAS  Article  Google Scholar 

  3. Radisavljevic, B., Radenovic, A., Brivio, J., Giacometti, V. & Kis, A. Single-layer MoS2 transistors. Nature Nanotech. 6, 147–150 (2011).

    CAS  Article  Google Scholar 

  4. Ghatak, S., Pal, A. N. & Ghosh, A. Nature of electronic states in atomically thin MoS2 field-effect transistors. ACS Nano 5, 7707–7712 (2011).

    CAS  Article  Google Scholar 

  5. Radisavljevic, B., Whitwick, M. B. & Kis, A. Integrated circuits and logic operations based on single-layer MoS2 . ACS Nano 5, 9934–9938 (2011).

    CAS  Article  Google Scholar 

  6. Late, D. J., Liu, B., Matte, H. S. S. R., Dravid, V. P. & Rao, C. N. R. Hysteresis in single-layer MoS2 field effect transistors. ACS Nano 6, 5635–5641 (2012).

    CAS  Article  Google Scholar 

  7. Bertolazzi, S., Krasnozhon, D. & Kis, A. Nonvolatile memory cells based on MoS2/graphene heterostructures. ACS Nano 7, 3246–3252 (2013).

    CAS  Article  Google Scholar 

  8. Choi, M. S. et al. Controlled charge trapping by molybdenum disulphide and graphene in ultrathin heterostructured memory devices. Nature Commun. 4, 1624 (2013).

    Article  Google Scholar 

  9. Mak, K. F., Lee, C., Hone, J., Shan, J. & Heinz, T. F. Atomically thin MoS2: a new direct-gap semiconductor. Phys. Rev. Lett. 105, 136805 (2010).

    Article  Google Scholar 

  10. Xu, X., Gabor, N. M., Alden, J. S., van der Zande, A. M. & McEuen, P. L. Photo-thermoelectric effect at a graphene interface junction. Nano Lett. 10, 562–566 (2010).

    CAS  Article  Google Scholar 

  11. Lemme, M. C. et al. Gate-activated photoresponse in a graphene p–n junction. Nano Lett. 11, 4134–4137 (2011).

    CAS  Article  Google Scholar 

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

    CAS  Article  Google Scholar 

  13. Freitag, M., Low, T. & Avouris, P. Increased responsivity of suspended graphene photodetectors. Nano Lett. 13, 1644–1648 (2013).

    CAS  Article  Google Scholar 

  14. Tielrooij, K. J. et al. Photoexcitation cascade and multiple hot-carrier generation in graphene. Nature Phys. 9, 248–252 (2013).

    CAS  Article  Google Scholar 

  15. Biswas, C. et al. Negative and positive persistent photoconductance in graphene. Nano Lett. 11, 4682–4687 (2011).

    CAS  Article  Google Scholar 

  16. Mueller, T., Xia, F. & Avouris, P. Graphene photodetectors for high-speed optical communications. Nature Photon. 4, 297–301 (2010).

    CAS  Article  Google Scholar 

  17. Freitag, M., Low, T., Xia, F. & Avouris, P. Photoconductivity of biased graphene. Nature Photon. 7, 53–59 (2013).

    CAS  Article  Google Scholar 

  18. Echtermeyer, T. et al. Strong plasmonic enhancement of photovoltage in graphene. Nature Commun. 2, 458 (2011).

    CAS  Article  Google Scholar 

  19. Chitara, B., Panchakarla, L. S., Krupanidhi, S. B. & Rao, C. N. R. Infrared photodetectors based on reduced graphene oxide and graphene nanoribbons. Adv. Mater. 23, 5419–5424 (2011).

    CAS  Article  Google Scholar 

  20. Ghosh, S., Sarker, B. K., Chunder, A., Zhai, L. & Khondaker, S. I. Position dependent photodetector from large area reduced graphene oxide thin films. Appl. Phys. Lett. 96, 163109 (2010).

    Article  Google Scholar 

  21. Kastalsky, A. & Hwang, J. Study of persistent photoconductivity effect in n-type selectively doped AlGaAs/GaAs heterojunction. Solid State Commun. 51, 317–322 (1984).

    CAS  Article  Google Scholar 

  22. Nathan, M. I. Persistent photoconductivity in AlGaAs/GaAs modulation doped layers and field effect transistors: a review. Solid State Electron. 29, 167–172 (1986).

    CAS  Article  Google Scholar 

  23. Queisser, H. J. & Theodorou, D. E. Decay kinetics of persistent photoconductivity in semiconductors. Phys. Rev. B 33, 4027–4033 (1986).

    CAS  Article  Google Scholar 

  24. Dawlaty, J. M. et al. Measurement of the optical absorption spectra of epitaxial graphene from terahertz to visible. Appl. Phys. Lett. 93, 131905 (2008).

    Article  Google Scholar 

  25. Nair, R. R. et al. Fine structure constant defines visual transparency of graphene. Science 320, 1308 (2008).

    CAS  Article  Google Scholar 

  26. Konstantatos, G. et al. Hybrid graphene–quantum dot phototransistors with ultrahigh gain. Nature Nanotech. 7, 363–368 (2012).

    CAS  Article  Google Scholar 

  27. Kim, M., Safron, N. S., Huang, C., Arnold, M. S. & Gopalan, P. Light-driven reversible modulation of doping in graphene. Nano Lett. 12, 182–187 (2012).

    CAS  Article  Google Scholar 

  28. Sachs, B. et al. Doping mechanisms in graphene–MoS2 hybrids. Preprint at http://arxiv.org/abs/1304.2236v1 (2013).

  29. Britnell, L. et al. Strong light–matter interactions in heterostructures of atomically thin films. Science 340, 1311–1314 (2013).

    CAS  Article  Google Scholar 

  30. Zomer, P. J., Dash, S. P., Tombros, N. & van Wees, B. J. A transfer technique for high mobility graphene devices on commercially available hexagonal boron nitride. Appl. Phys. Lett. 99, 232104 (2011).

    Article  Google Scholar 

  31. Borghetti, J. et al. Optoelectronic switch and memory devices based on polymer-functionalized carbon nanotube transistors. Adv. Mater. 18, 2535–2540 (2006).

    CAS  Article  Google Scholar 

  32. Star, A., Lu, Y., Bradley, K. & Grüner, G. Nanotube optoelectronic memory devices. Nano Lett. 4, 1587–1591 (2004).

    CAS  Article  Google Scholar 

  33. Shi, Y. et al. Photoconductivity from carbon nanotube transistors activated by photosensitive polymers. J. Phys. Chem. C 112, 18201–18206 (2008).

    CAS  Article  Google Scholar 

  34. Dutta, S. & Narayan, K. Gate-voltage control of optically-induced charges and memory effects in polymer field-effect transistors. Adv. Mater. 16, 2151–2155 (2004).

    CAS  Article  Google Scholar 

Download references

Acknowledgements

The authors acknowledge the Department of Science and Technology (DST) for a funded project under Nanomission. S.R. acknowledges support under grant no. SR/S2/CMP-02/2007 (DST).

Author information

Authors and Affiliations

Authors

Contributions

K.R. and A.G. conceived and designed the experiments. K.R. and M.P. performed the experiments. K.R., M.P. and A.G. analysed the data. S.G., T.P.S. and K.R. developed the heterostructure fabrication technique used in the experiment. G.R. and S.R. contributed CVD graphene material. K.R., M.P. and A.G. co-wrote the paper. All authors discussed the results and commented on the manuscript.

Corresponding authors

Correspondence to Kallol Roy or Arindam Ghosh.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary information

Supplementary Information (PDF 1389 kb)

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Roy, K., Padmanabhan, M., Goswami, S. et al. Graphene–MoS2 hybrid structures for multifunctional photoresponsive memory devices. Nature Nanotech 8, 826–830 (2013). https://doi.org/10.1038/nnano.2013.206

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nnano.2013.206

This article is cited by

Search

Quick links

Find nanotechnology articles, nanomaterial data and patents all in one place. Visit Nano by Nature Research