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A flexoelectric microelectromechanical system on silicon

Nature Nanotechnology volume 11, pages 263–266 (2016)Cite this article

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Abstract

Flexoelectricity allows a dielectric material to polarize in response to a mechanical bending moment1 and, conversely, to bend in response to an electric field2. Compared with piezoelectricity, flexoelectricity is a weak effect of little practical significance in bulk materials. However, the roles can be reversed at the nanoscale3. Here, we demonstrate that flexoelectricity is a viable route to lead-free microelectromechanical and nanoelectromechanical systems. Specifically, we have fabricated a silicon-compatible thin-film cantilever actuator with a single flexoelectrically active layer of strontium titanate with a figure of merit (curvature divided by electric field) of 3.33 MV−1, comparable to that of state-of-the-art piezoelectric bimorph cantilevers.

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Figure 1: Schematic comparing flexoelectric actuation and piezoelectric bimorph actuation in nanoscale actuators.
Figure 2: Experimental design.
Figure 3: Experimental characterization of flexoelectricity as a function of frequency and electric field.
Figure 4: Comparison of the performance of flexoelectric SrTiO3 with those of state-of-the-art piezoelectric bimorphs.

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Acknowledgements

The work at ICN2 was funded by an ERC Starting Grant from the EU (Project No. 308023), a National Plan grant from Spain (FIS2013-48668-C2-1-P) and the Severo Ochoa Excellence programme. The work at Cornell University was supported by the National Science Foundation (Nanosystems Engineering Research Center for Translational Applications of Nanoscale Multiferroic Systems) under grant number EEC-1160504. The authors thank E. Cuche, J. Parent, E. Solanas and Y. Emery for discussions.

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Author notes

  1. Umesh Kumar Bhaskar and Nirupam Banerjee: These authors contributed equally to this work

Authors and Affiliations

  1. ICN2 – Institut Catala de Nanociencia i Nanotecnologia, CSIC and The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra, Barcelona, 08193, Spain

    Umesh Kumar Bhaskar, Amir Abdollahi & Gustau Catalan

  2. Faculty of Science and Technology and MESA+ Institute for Nanotechnology, University of Twente, PO Box 217, AE Enschede, 7500, The Netherlands

    Nirupam Banerjee & Guus Rijnders

  3. Department of Materials Science and Engineering, Cornell University, Ithaca, 14853, New York, USA

    Zhe Wang & Darrell G. Schlom

  4. Kavli Institute at Cornell for Nanoscale Science, Ithaca, 14853, New York, USA

    Darrell G. Schlom

  5. ICREA – Institucio Catalana de Recerca i Estudis Avançats, Barcelona, 08010, Spain

    Gustau Catalan

Authors
  1. Umesh Kumar Bhaskar
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  2. Nirupam Banerjee
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  3. Amir Abdollahi
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  4. Zhe Wang
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  5. Darrell G. Schlom
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  7. Gustau Catalan
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Contributions

G.C. and U.B. conceived and designed the experiments. N.B. designed and made the cantilevers under the supervision of G.R. U.B. performed and analysed the inverse flexoelectric characterizations under the supervision of G.C. A.A. performed the self-consistent continuum modelling and simulations. Z.W. performed the molecular beam epitaxy growth of the template layer under the supervision of D.S. U.B. and G.C. wrote the paper with the help of all the other authors. All authors discussed the results, commented on the manuscript and gave their approval to the final version of the manuscript.

Corresponding authors

Correspondence to Umesh Kumar Bhaskar or Gustau Catalan.

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The authors declare no competing financial interests.

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Bhaskar, U., Banerjee, N., Abdollahi, A. et al. A flexoelectric microelectromechanical system on silicon. Nature Nanotech 11, 263–266 (2016). https://doi.org/10.1038/nnano.2015.260

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