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Robust resistive memory devices using solution-processable metal-coordinated azo aromatics

Nature Materials volume 16, pages 1216–1224 (2017)Cite this article

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A Corrigendum to this article was published on 19 December 2017

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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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Figure 1: Structure and device characteristics.
Figure 2: Device statistics.
Figure 3: Device performance.
Figure 4: Detection of redox states by in situ spectroscopy.
Figure 5: Correlation between Raman peaks and film conductance.
Figure 6: Effect of counterion.

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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.

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Author notes

  1. Svante Hedström & Surajit Saha

    Present address: Department of Physics, Indian Institute of Science Education and Research (IISER), Bhopal, 462066, India

  2. Adam J. Matula, Santi P. Rath and Svante Hedström: These authors contributed equally to this work.

Authors and 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

  10. Fysikum, Stockholm University, 10691, Stockholm, Sweden

    Svante Hedström

Authors
  1. Sreetosh Goswami
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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.

Corresponding authors

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

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Goswami, S., Matula, A., Rath, S. et al. Robust resistive memory devices using solution-processable metal-coordinated azo aromatics. Nature Mater 16, 1216–1224 (2017). https://doi.org/10.1038/nmat5009

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