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Electrochemical dynamics of nanoscale metallic inclusions in dielectrics

Nature Communications volume 5, Article number: 4232 (2014) | Download Citation


Nanoscale metal inclusions in or on solid-state dielectrics are an integral part of modern electrocatalysis, optoelectronics, capacitors, metamaterials and memory devices. The properties of these composite systems strongly depend on the size, dispersion of the inclusions and their chemical stability, and are usually considered constant. Here we demonstrate that nanoscale inclusions (for example, clusters) in dielectrics dynamically change their shape, size and position upon applied electric field. Through systematic in situ transmission electron microscopy studies, we show that fundamental electrochemical processes can lead to universally observed nucleation and growth of metal clusters, even for inert metals like platinum. The clusters exhibit diverse dynamic behaviours governed by kinetic factors including ion mobility and redox rates, leading to different filament growth modes and structures in memristive devices. These findings reveal the microscopic origin behind resistive switching, and also provide general guidance for the design of novel devices involving electronics and ionics.

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The work at the University of Michigan was supported by the AFOSR through MURI grant FA9550-12-1-0038 (Y.Y and W.D.L.), the U.S. Department of Energy, Office of Basic Energy Sciences under Awards DE-FG02-07ER46416 (P.G. and X.P.), the National Science Foundation (NSF) through ECCS-0954621 (W.D.L.) and DMR-0723032 (TEM instrument). The work at RWTH-Aachen University was supported in parts by the DFG priority program SFB 917. We acknowledge Dr S. Kim, C. Du and S. Gaba for helpful discussions.

Author information

Author notes

    • Peng Gao

    Present address: Brookhaven National Laboratory, Upton, New York 11973, USA


  1. Department of Electrical Engineering and Computer Science, the University of Michigan, Ann Arbor, Michigan 48109, USA

    • Yuchao Yang
    • , ShinHyun Choi
    •  & Wei D. Lu
  2. Department of Materials Science and Engineering, the University of Michigan, Ann Arbor, Michigan 48109, USA

    • Peng Gao
    • , Linze Li
    •  & Xiaoqing Pan
  3. Institut für Werkstoffe der Elektrotechnik II, RWTH Aachen University, 52074 Aachen, Germany

    • Stefan Tappertzhofen
    • , Rainer Waser
    •  & Ilia Valov
  4. Peter Grünberg Institute 7, Research Centre Jülich GmbH, 52425 Jülich, Germany

    • Rainer Waser
    •  & Ilia Valov


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Y.Y., I.V. and W.D.L. conceived, directed and analysed all experimental research and prepared the manuscript. S.T., S.C., Y.Y. prepared the samples. Y.Y., P.G. and L.L. performed TEM imaging and electrical measurements. W.D.L., I.V., R.W. and X.P. constructed the research frame. All authors discussed the results and implications and commented on the manuscript at all stages.

Competing interests

The authors declare no competing financial interests.

Corresponding authors

Correspondence to Ilia Valov or Wei D. Lu.

Supplementary information

PDF files

  1. 1.

    Supplementary Figures, Notes and References

    Supplementary Figures 1-3, Supplementary Notes 1-3 and Supplementary References


  1. 1.

    Supplementary Movie 1

    Real-time TEM observation of the dynamics of Ag nanoclusters in SiO2. A voltage of 3 V was applied on the left electrode.

  2. 2.

    Supplementary Movie 2

    Real-time TEM observation of the dynamic splitting and merging processes of a single Ag nanocluster. A voltage of 3 V was applied on the left electrode.

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    Supplementary Movie 3

    Real-time TEM observation of the dynamics of Cu nanoclusters in SiO2 driven. A voltage of 6 V was applied on the left electrode.

  4. 4.

    Supplementary Movie 4

    Real-time TEM observation of the dynamics of Ni nanoclusters in SiO2. A voltage of 15 V was applied on the left electrode.

  5. 5.

    Supplementary Movie 5

    Real-time TEM observation of the bootstrapping filament growth and void channel creation/refilling processes. A voltage of 8 V was applied on the Ag electrode. The movie is played at a speed of 8X.

  6. 6.

    Supplementary Movie 6

    Real-time TEM observation of filament growth dynamics with a nanoscale electrode area. A constant voltage of 7 V was applied on the Ag electrode. The SiO2 thickness is 20 nm. The movie is played at a speed of 2X.

  7. 7.

    Supplementary Movie 7

    Real-time TEM observation of filament growth in a relatively large Ag/SiO2/W device. A constant voltage of 4 V was applied on the Ag electrode. The movie is played at a speed of 2X.

  8. 8.

    Supplementary Movie 8

    Real-time TEM observation of filament growth dynamics in another small-scale Ag/SiO2/W device, showing apparent electrode consumption. A constant voltage of 5 V was applied on the Ag electrode. The movie is played at a speed of 1X.

  9. 9.

    Supplementary Movie 9

    Real-time TEM observation of the refilling process of the nano-gap, leading to recovery of the electrical contact. A constant voltage of 2 V was applied on the Ag electrode. The movie is played at a speed of 2X.

  10. 10.

    Supplementary Movie 10

    Real-time TEM observation showing the transition between two different filament growth modes. A constant voltage of 2 V was applied on the Ag electrode. The movie is played at a speed of 2X.

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