Letter | Published:

Multi-terminal memtransistors from polycrystalline monolayer molybdenum disulfide

Nature volume 554, pages 500504 (22 February 2018) | Download Citation

Abstract

Memristors are two-terminal passive circuit elements that have been developed for use in non-volatile resistive random-access memory and may also be useful in neuromorphic computing1,2,3,4,5,6. Memristors have higher endurance and faster read/write times than flash memory4,7,8 and can provide multi-bit data storage. However, although two-terminal memristors have demonstrated capacity for basic neural functions, synapses in the human brain outnumber neurons by more than a thousandfold, which implies that multi-terminal memristors are needed to perform complex functions such as heterosynaptic plasticity3,9,10,11,12,13. Previous attempts to move beyond two-terminal memristors, such as the three-terminal Widrow–Hoff memristor14 and field-effect transistors with nanoionic gates15 or floating gates16, did not achieve memristive switching in the transistor17. Here we report the experimental realization of a multi-terminal hybrid memristor and transistor (that is, a memtransistor) using polycrystalline monolayer molybdenum disulfide (MoS2) in a scalable fabrication process. The two-dimensional MoS2 memtransistors show gate tunability in individual resistance states by four orders of magnitude, as well as large switching ratios, high cycling endurance and long-term retention of states. In addition to conventional neural learning behaviour of long-term potentiation/depression, six-terminal MoS2 memtransistors have gate-tunable heterosynaptic functionality, which is not achievable using two-terminal memristors. For example, the conductance between a pair of floating electrodes (pre- and post-synaptic neurons) is varied by a factor of about ten by applying voltage pulses to modulatory terminals. In situ scanning probe microscopy, cryogenic charge transport measurements and device modelling reveal that the bias-induced motion of MoS2 defects drives resistive switching by dynamically varying Schottky barrier heights. Overall, the seamless integration of a memristor and transistor into one multi-terminal device could enable complex neuromorphic learning and the study of the physics of defect kinetics in two-dimensional materials18,19,20,21,22.

  • Subscribe to Nature for full access:

    $199

    Subscribe

Additional access options:

Already a subscriber?  Log in  now or  Register  for online access.

References

  1. 1.

    , , & The missing memristor found. Nature 453, 80–83 (2008); corrigendum 459, 1154 (2009)

  2. 2.

    et al. Memristive switching mechanism for metal/oxide/metal nanodevices. Nat. Nanotechnol. 3, 429–433 (2008)

  3. 3.

    , & Synaptic electronics: materials, devices and applications. Nanotechnology 24, 382001 (2013)

  4. 4.

    & Emerging memory technologies: recent trends and prospects. IEEE Sol. Stat. Circuit Mag. 8, 43–56 (2016)

  5. 5.

    , & Memristive devices for computing. Nat. Nanotechnol. 8, 13–24 (2013)

  6. 6.

    , , & Redox-based resistive switching memories – nanoionic mechanisms, prospects, and challenges. Adv. Mater. 21, 2632–2663 (2009)

  7. 7.

    & Memory effects in complex materials and nanoscale systems. Adv. Phys. 60, 145–227 (2011)

  8. 8.

    et al. Metal-oxide RRAM. Proc. IEEE 100, 1951–1970 (2012)

  9. 9.

    Memristor-based neural networks. J. Phys. D 46, 093001 (2013)

  10. 10.

    et al. Integration of nanoscale memristor synapses in neuromorphic computing architectures. Nanotechnology 24, 384010 (2013)

  11. 11.

    et al. Nanoscale memristor device as synapse in neuromorphic systems. Nano Lett. 10, 1297–1301 (2010)

  12. 12.

    et al. Pattern recognition using carbon nanotube synaptic transistors with an adjustable weight update protocol. ACS Nano 11, 2814–2822 (2017)

  13. 13.

    et al. Experimental demonstration of a second-order memristor and its ability to biorealistically implement synaptic plasticity. Nano Lett. 15, 2203–2211 (2015)

  14. 14.

    An Adaptive Adaline Neuron using Chemical Memristors. Technical Report 1553–2 www-isl.stanford.edu/~widrow/papers/t1960anadaptive.pdf (Stanford Electronics Laboratories, 1960)

  15. 15.

    et al. Ionic/electronic hybrid materials integrated in a synaptic transistor with signal processing and learning functions. Adv. Mater. 22, 2448–2453 (2010)

  16. 16.

    , , & A single-transistor silicon synapse. IEEE Trans. Electron Dev. 43, 1972–1980 (1996)

  17. 17.

    Memristive systems analysis of 3-terminal devices. In IEEE Int. Conf. on Electronics, Circuits and Systems 930–933 (IEEE, 2010)

  18. 18.

    et al. Dislocation motion and grain boundary migration in two-dimensional tungsten disulphide. Nat. Commun. 5, 4867 (2014)

  19. 19.

    et al. From point to extended defects in two-dimensional MoS2: Evolution of atomic structure under electron irradiation. Phys. Rev. B 88, 035301 (2013)

  20. 20.

    et al. Gate-tunable memristive phenomena mediated by grain boundaries in single-layer MoS2. Nat. Nanotechnol. 10, 403–406 (2015)

  21. 21.

    , & An anomalous formation pathway for dislocation-sulfur vacancy complexes in polycrystalline monolayer MoS2. Nano Lett. 15, 6855–6861 (2015)

  22. 22.

    et al. Layered memristive and memcapacitive switches for printable electronics. Nat. Mater. 14, 199–204 (2015)

  23. 23.

    et al. Thermally assisted nonvolatile memory in monolayer MoS2 transistors. Nano Lett. 16, 6445–6451 (2016)

  24. 24.

    et al. Mimicking neurotransmitter release in chemical synapses via hysteresis engineering in MoS2 transistors. ACS Nano 11, 3110–3118 (2017)

  25. 25.

    Resistance switching memories are memristors. Appl. Phys., A Mater. Sci. Process. 102, 765–783 (2011)

  26. 26.

    Control of Schottky barrier height using highly doped surface layers. Solid-State Electron. 19, 537–543 (1976)

  27. 27.

    & Physics of Semiconductor Devices (Wiley-Interscience, 2006)

  28. 28.

    , , & A versatile memristor model with nonlinear dopant kinetics. IEEE Trans. Electron Dev. 58, 3099–3105 (2011)

  29. 29.

    & Breakdown of high-performance monolayer MoS2 transistors. ACS Nano 6, 10070–10075 (2012)

  30. 30.

    , & Memristive physically evolving networks enabling the emulation of heterosynaptic plasticity. Adv. Mater. 27, 7720–7727 (2015)

  31. 31.

    et al. 3D Ta/TaOx/TiO2/Ti synaptic array and linearity tuning of weight update for hardware neural network applications. Nanotechnology 27, 365204 (2016)

  32. 32.

    & Synaptic modifications in cultured hippocampal neurons: dependence on spike timing, synaptic strength, and postsynaptic cell type. J. Neurosci. 18, 10464–10472 (1998)

  33. 33.

    et al. Mutual photoluminescence quenching and photovoltaic effect in large-area single-layer MoS2–polymer heterojunctions. ACS Nano 10, 10573–10579 (2016)

  34. 34.

    et al. Anomalous lattice vibrations of single- and few-layer MoS2. ACS Nano 4, 2695–2700 (2010)

  35. 35.

    et al. Control of Schottky barriers in single layer MoS2 transistors with ferromagnetic contacts. Nano Lett. 13, 3106–3110 (2013)

  36. 36.

    & Memristive devices and systems. Proc. IEEE 64, 209–223 (1976)

  37. 37.

    – the missing circuit element. IEEE Trans. Circuit Theory 18, 507–519 (1971)

  38. 38.

    Reducing the effective height of a Schottky barrier using low-energy ion implantation. Appl. Phys. Lett. 24, 369–371 (1974)

  39. 39.

    Increasing the effective height of a Schottky barrier using low-energy ion implantation. Appl. Phys. Lett. 25, 75–77 (1974)

  40. 40.

    . et al. Int. Electron Devices Meeting 2000 57–60 (IEEE, 2000)

  41. 41.

    Electrical transport in Schottky barrier MOSFETs. PhD thesis, Yale Univ. (2001)

  42. 42.

    Resistive switching in transition metal oxides. Mater. Today 11, 28–36 (2008)

  43. 43.

    , , & Uncovering two competing switching mechanisms for epitaxial and ultrathin strontium titanate-based resistive switching bits. ACS Nano 9, 10737–10748 (2015)

  44. 44.

    et al. Ferroelectric tunnel junction for dense cross-point arrays. ACS Appl. Mater. Interfaces 7, 22348–22354 (2015)

  45. 45.

    et al. Ferroelectric tunnel memristor. Nano Lett. 12, 5697–5702 (2012)

  46. 46.

    et al. Interface band profiles of Mott-insulator/Nb:SrTiO3 heterojunctions as investigated by optical spectroscopy. Phys. Rev. B 82, 201101 (2010)

  47. 47.

    , , & Hysteretic current–voltage characteristics and resistance switching at a rectifying Ti/Pr0.7Ca0.3MnO3 interface. Appl. Phys. Lett. 85, 4073–4075 (2004)

  48. 48.

    & Solid State Electronic Devices (Prentice Hall, 1995)

  49. 49.

    , , & A versatile memristor model with nonlinear dopant kinetics. IEEE Trans. Electron Dev. 58, 3099–3105 (2011)

  50. 50.

    et al. Impact of contact on the operation and performance of back-gated monolayer MoS2 field-effect-transistors. ACS Nano 9, 7904–7912 (2015)

  51. 51.

    et al. Influence of stoichiometry on the optical and electrical properties of chemical vapor deposition derived MoS2. ACS Nano 8, 10551–10558 (2014)

  52. 52.

    , , & High-performance molybdenum disulfide field-effect transistors with spin tunnel contacts. ACS Nano 8, 476–482 (2014)

  53. 53.

    , , & Statistical study on the Schottky barrier reduction of tunneling contacts to CVD synthesized MoS2. Nano Lett. 16, 276–281 (2016)

  54. 54.

    et al. High mobility MoS2 transistor with low Schottky barrier contact by using atomic thick h-BN as a tunneling layer. Adv. Mater. 28, 8302–8308 (2016)

Download references

Acknowledgements

This research was supported by the Materials Research Science and Engineering Center (MRSEC) of Northwestern University (NSF DMR-1720139) and the 2-DARE programme (NSF EFRI-1433510). The CVD growth of MoS2 was supported by the National Institute of Standards and Technology (NIST CHiMaD 70NANB14H012). Charge transport instrumentation was funded by an ONR DURIP grant (ONR N00014-16-1-3179). H.-S.L. acknowledges the Basic Science Research Program of the National Research Foundation of Korea (NRF), which is funded by the Ministry of Education (2017R1A6A3A03008332). H.B. acknowledges support from the NSERC Postgraduate Scholarship–Doctoral Program. H.B. and M.E.B. acknowledge support from the National Science Foundation through a Graduate Research Fellowship. For this work, we used the Northwestern University NUANCE Center and the Northwestern University Micro/Nano Fabrication Facility (NUFAB), which are partially supported by the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS-1542205), the Materials Research Science and Engineering Center (NSF DMR-1720139), the State of Illinois and Northwestern University. We thank J. J. McMorrow for assistance with photolithography, X. Liu for assistance with lateral force microscopy and S. Mohseni for assistance with atomic force microscopy.

Author information

Author notes

    • Vinod K. Sangwan
    •  & Hong-Sub Lee

    These authors contributed equally to this work.

Affiliations

  1. Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA

    • Vinod K. Sangwan
    • , Hong-Sub Lee
    • , Hadallia Bergeron
    • , Itamar Balla
    • , Megan E. Beck
    • , Kan-Sheng Chen
    •  & Mark C. Hersam
  2. Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA

    • Mark C. Hersam
  3. Department of Electrical Engineering and Computer Science, Northwestern University, Evanston, Illinois 60208, USA

    • Mark C. Hersam

Authors

  1. Search for Vinod K. Sangwan in:

  2. Search for Hong-Sub Lee in:

  3. Search for Hadallia Bergeron in:

  4. Search for Itamar Balla in:

  5. Search for Megan E. Beck in:

  6. Search for Kan-Sheng Chen in:

  7. Search for Mark C. Hersam in:

Contributions

V.K.S., H.-S.L. and M.C.H. conceived the idea and designed the experiments. V.K.S. and H.-S.L. fabricated all the devices and performed measurements and analysis. H.B. and I.B. handled the growth of MoS2 and conducted materials characterization. V.K.S. developed the memtransistor model. M.E.B. assisted in model fitting and device fabrication. K.-S.C. assisted in electrostatic force microscopy. All authors wrote the manuscript and discussed the results at all stages.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Mark C. Hersam.

Reviewer Information Nature thanks X. Liang and the other anonymous reviewer(s) for their contribution to the peer review of this work.

Publisher's note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Extended data

About this article

Publication history

Received

Accepted

Published

DOI

https://doi.org/10.1038/nature25747

Rights and permissions

To obtain permission to re-use content from this article visit RightsLink.

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.