• A Corrigendum to this article was published on 19 December 2017

This article has been updated

Abstract

Non-volatile memories will play a decisive role in the next generation of digital technology. Flash memories are currently the key player in the field, yet they fail to meet the commercial demands of scalability and endurance. Resistive memory devices, and in particular memories based on low-cost, solution-processable and chemically tunable organic materials, are promising alternatives explored by the industry. However, to date, they have been lacking the performance and mechanistic understanding required for commercial translation. Here we report a resistive memory device based on a spin-coated active layer of a transition-metal complex, which shows high reproducibility (350 devices), fast switching (≤30 ns), excellent endurance (1012 cycles), stability (>106 s) and scalability (down to 60 nm2). In situ Raman and ultraviolet–visible spectroscopy alongside spectroelectrochemistry and quantum chemical calculations demonstrate that the redox state of the ligands determines the switching states of the device whereas the counterions control the hysteresis. This insight may accelerate the technological deployment of organic resistive memories.

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Change history

  • 04 December 2017

    In the version of this Article originally published, the x-axis units of Fig. 3a were incorrectly given as ms, and should have read μs. This has now been corrected. Two places in the text also needed amending to reflect this change: the penultimate sentence of Fig. 3c,d caption now starts 'Microsecond pulses are used', and the penultimate sentence of the second paragraph of 'Device performance' has been changed to begin 'Device A was measured continuously over 230 days with microsecond write–read pulses'. All have now been corrected in the online versions of the Article.

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Acknowledgements

T.V. would like to acknowledge support from the National Research Foundation under Competitive Research Program (NRF2015NRF_CRP001_015) and (NRF-CRP10-2012-02). Sreebrata Goswami would like to acknowledge the financial support of SERB, India through grants SR/S2/JCB-09/2011 and EMR/2014/000520. V.S.B. acknowledges supercomputing time from NERSC and from the Yale High Performance Computing Center and support by the Air Force Office of Scientific Research (AFOSR) through grant #FA9550-13-1-0020. Sreetosh Goswami is supported by NUS Graduate School for Integrative Science and Engineering (NGS). A.J.M. is supported by the National Science Foundation Graduate Research Fellowship under Grant No. DGE-1122492. C.A.N. acknowledges the Minister of Education (MOE) for supporting this research under award No. MOE2015-T2-1-050. J.M. is supported by the National Research Foundation, Prime Minister’s Office, Singapore under its Medium sized centre programme. We would like to thank Centre of Integrated Circuit and Failure Analysis (CICFAR) for providing the AFM facility. We thank S. B. Ogale, M. Reed and C. Jingsheng for their comments on the work and the manuscript. Sreebrata Goswami thanks A. Llobet, ICIQ for spectroelectrochemical data.

Author information

Author notes

    • Adam J. Matula
    • , Santi P. Rath
    •  & Svante Hedström

    These authors contributed equally to this work.

    • Svante Hedström
    •  & Surajit Saha

    Present addresses: Fysikum, Stockholm University, 10691 Stockholm, Sweden (S.H.); Department of Physics, Indian Institute of Science Education and Research (IISER), Bhopal 462066, India (S.Saha).

Affiliations

  1. NUSNNI-NanoCore, National University of Singapore, Singapore 117411, Singapore

    • Sreetosh Goswami
    • , Surajit Saha
    • , Meenakshi Annamalai
    • , Abhijeet Patra
    • , Siddhartha Ghosh
    • , Hariom Jani
    • , Soumya Sarkar
    • , Mallikarjuna Rao Motapothula
    •  & T. Venkatesan
  2. NUS Graduate School for Integrative Science and Engineering, National University of Singapore, Singapore 117456, Singapore

    • Sreetosh Goswami
    • , Abhijeet Patra
    • , Hariom Jani
    • , Soumya Sarkar
    •  & T. Venkatesan
  3. Department of Chemistry, Yale University, New Haven, Connecticut 06520, USA

    • Adam J. Matula
    • , Svante Hedström
    •  & Victor S. Batista
  4. Department of Inorganic Chemistry, Indian Association for the Cultivation of Science (IACS), Jadavpur, Kolkata 700032, India

    • Santi P. Rath
    • , Debabrata Sengupta
    •  & Sreebrata Goswami
  5. Department of Chemistry, National University of Singapore, Singapore 117543, Singapore

    • Christian A. Nijhuis
  6. Centre for Advanced 2D Materials, National University of Singapore, Singapore 117546, Singapore

    • Christian A. Nijhuis
    •  & Jens Martin
  7. Department of Physics, National University of Singapore, Singapore 117542, Singapore

    • Jens Martin
    •  & T. Venkatesan
  8. Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117583, Singapore

    • T. Venkatesan
  9. Materials Science and Engineering Department, National University of Singapore, Singapore 117575, Singapore

    • T. Venkatesan

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Contributions

Sreetosh Goswami devised the project, fabricated the devices, and did the J(V) measurements and the in situ spectroscopies. S.Saha helped Sreetosh Goswami with the in situ Raman measurement technique and data analysis. A.J.M. and S.H. built the theoretical models and performed the DFT calculations. S.P.R. and D.S. synthesized and characterized the compounds in solution. M.A. did the c-AFM measurements and analysis. A.P. did the AFM measurement and participated in discussions. Siddhartha Ghosh participated in J(V) measurement, analysis and strategic discussions. H.J., S.Sarkar helped Sreetosh Goswami. to fabricate NP devices. M.R.M. conducted the Rutherford Back Scattering (RBS) measurements. J.M. analysed the transport data and guided Sreetosh Goswami for experimental planning and data interpretation. C.A.N. provided guidance in experimental designs and understanding the phenomena. V.S.B. supervised the theoretical contributions. Sreebrata Goswami introduced the materials and supervised their synthesis and characterization. T.V. supervised the entire research programme. All the authors participated in manuscript writing.

Competing interests

The authors declare no competing financial interests.

Corresponding authors

Correspondence to Sreebrata Goswami or Victor S. Batista or T. Venkatesan.

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DOI

https://doi.org/10.1038/nmat5009

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