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Nano Research 2022, 15(11): 9881-9889 https://doi.org/10.1007/s12274-022-4535-8
Research Article | Open Access | Issue | Published: 25 June 2022

Localised solid-state nanopore fabrication via controlled breakdown using on-chip electrodes

Show Author's Information Jasper P. Fried1,2( ),  Jacob L. Swett1,  Binoy Paulose Nadappuram3,  Aleksandra Fedosyuk3,  Alex Gee1,  Ondrej E. Dyck4,  James R. Yates5,  Aleksandar P. Ivanov3,  Joshua B. Edel3,  Jan A. Mol6
Department of Materials, University of Oxford, Oxford, OX1 3PH, UK
School of Chemistry, University of New South Wales, Sydney, New South Wales 2052, Australia
Department of Chemistry, Imperial College London, London, W12 0BZ, UK
Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA
Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, Oeiras 2780-157, Portugal
School of Physics and Astronomy, Queen Mary University of London, London, E1 4NS, UK
Keywords:
dielectric breakdown, nanofabrication, solid-state nanopores, single-molecule sensing, nanopore arrays
Topics:
Nanosensors
Cite this article:
Fried JP, Swett JL, Nadappuram BP, et al. Localised solid-state nanopore fabrication via controlled breakdown using on-chip electrodes. Nano Research, 2022, 15(11): 9881-9889. https://doi.org/10.1007/s12274-022-4535-8
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Abstract Full text Electronic supplementary material About this article

Controlled breakdown has recently emerged as a highly accessible technique to fabricate solid-state nanopores. However, in its most common form, controlled breakdown creates a single nanopore at an arbitrary location in the membrane. Here, we introduce a new strategy whereby breakdown is performed by applying the electric field between an on-chip electrode and an electrolyte solution in contact with the opposite side of the membrane. We demonstrate two advantages of this method. First, we can independently fabricate multiple nanopores at given positions in the membrane by localising the applied field to the electrode. Second, we can create nanopores that are self-aligned with complementary nanoelectrodes by applying voltages to the on-chip electrodes to locally heat the membrane during controlled breakdown. This new controlled breakdown method provides a path towards the affordable, rapid, and automatable fabrication of arrays of nanopores self-aligned with complementary on-chip nanostructures.


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Electronic supplementary material
About this article

Localised solid-state nanopore fabrication via controlled breakdown using on-chip electrodes

Show Author's information Jasper P. Fried1,2( ), Jacob L. Swett1, Binoy Paulose Nadappuram3, Aleksandra Fedosyuk3, Alex Gee1, Ondrej E. Dyck4, James R. Yates5, Aleksandar P. Ivanov3, Joshua B. Edel3, Jan A. Mol6
Department of Materials, University of Oxford, Oxford, OX1 3PH, UK
School of Chemistry, University of New South Wales, Sydney, New South Wales 2052, Australia
Department of Chemistry, Imperial College London, London, W12 0BZ, UK
Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA
Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, Oeiras 2780-157, Portugal
School of Physics and Astronomy, Queen Mary University of London, London, E1 4NS, UK

Abstract

Controlled breakdown has recently emerged as a highly accessible technique to fabricate solid-state nanopores. However, in its most common form, controlled breakdown creates a single nanopore at an arbitrary location in the membrane. Here, we introduce a new strategy whereby breakdown is performed by applying the electric field between an on-chip electrode and an electrolyte solution in contact with the opposite side of the membrane. We demonstrate two advantages of this method. First, we can independently fabricate multiple nanopores at given positions in the membrane by localising the applied field to the electrode. Second, we can create nanopores that are self-aligned with complementary nanoelectrodes by applying voltages to the on-chip electrodes to locally heat the membrane during controlled breakdown. This new controlled breakdown method provides a path towards the affordable, rapid, and automatable fabrication of arrays of nanopores self-aligned with complementary on-chip nanostructures.

Keywords: dielectric breakdown, nanofabrication, solid-state nanopores, single-molecule sensing, nanopore arrays

References(68)

[1]

Yusko, E. C.; Bruhn, B. R.; Eggenberger, O. M.; Houghtaling, J.; Rollings, R. C.; Walsh, N. C.; Nandivada, S.; Pindrus, M.; Hall, A. R.; Sept, D. et al. Real-time shape approximation and fingerprinting of single proteins using a nanopore. Nat. Nanotechnol. 2017, 12, 360–367.
DOI Google Scholar
[2]

Alfaro, J. A.; Bohländer, P.; Dai, M. J.; Filius, M.; Howard, C. J.; Van Kooten, X. F.; Ohayon, S.; Pomorski, A.; Schmid, S.; Aksimentiev, A. et al. The emerging landscape of single-molecule protein sequencing technologies. Nat. Methods 2021, 18, 604–617.
DOI Google Scholar
[3]

Restrepo-Pérez, L.; Joo, C.; Dekker, C. Paving the way to single-molecule protein sequencing. Nat. Nanotechnol. 2018, 13, 786–796.
DOI Google Scholar
[4]

Bell, N. A. W.; Keyser, U. F. Digitally encoded DNA nanostructures for multiplexed, single-molecule protein sensing with nanopores. Nat. Nanotechnol. 2016, 11, 645–651.
DOI Google Scholar
[5]

Chen, K. K.; Zhu, J. B.; Bošković, F.; Keyser, U. F. Nanopore-based DNA hard drives for rewritable and secure data storage. Nano Lett. 2020, 20, 3754–3760.
DOI Google Scholar
[6]

Chuah, K.; Wu, Y. F.; Vivekchand, S. R. C.; Gaus, K.; Reece, P. J.; Micolich, A. P.; Gooding, J. J. Nanopore blockade sensors for ultrasensitive detection of proteins in complex biological samples. Nat. Commun. 2019, 10, 2109.
DOI Google Scholar
[7]

Wu, Y. F.; Yao, Y.; Cheong, S.; Tilley, R. D.; Gooding, J. J. Selectively detecting attomolar concentrations of proteins using gold lined nanopores in a nanopore blockade sensor. Chem. Sci. 2020, 11, 12570–12579.
DOI Google Scholar
[8]

Cai, S. L.; Pataillot-Meakin, T.; Shibakawa, A.; Ren, R.; Bevan, C. L.; Ladame, S.; Ivanov, A. P.; Edel, J. B. Single-molecule amplification-free multiplexed detection of circulating microRNA cancer biomarkers from serum. Nat. Commun. 2021, 12, 3515.
DOI Google Scholar
[9]

Rozevsky, Y.; Gilboa, T.; Van Kooten, X. F.; Kobelt, D.; Huttner, D.; Stein, U.; Meller, A. Quantification of mRNA expression using single-molecule nanopore sensing. ACS Nano 2020, 14, 13964–13974.
DOI Google Scholar
[10]

Dekker, C. Solid-state nanopores. Nat. Nanotechnol. 2007, 2, 209–215.
DOI Google Scholar
[11]

Miles, B. N.; Ivanov, A. P.; Wilson, K. A.; Doğan, F.; Japrung, D.; Edel, J. B. Single molecule sensing with solid-state nanopores: Novel materials, methods, and applications. Chem. Soc. Rev. 2013, 42, 15–28.
DOI Google Scholar
[12]

Xue, L.; Yamazaki, H.; Ren, R.; Wanunu, M.; Ivanov, A. P.; Edel, J. B. Solid-state nanopore sensors. Nat. Rev. Mater. 2020, 5, 952.
DOI Google Scholar
[13]

Tsutsui, M.; Ryuzaki, S.; Yokota, K.; He, Y. H.; Washio, T.; Tamada, K.; Kawai, T. Field effect control of translocation dynamics in surround-gate nanopores. Commun. Mater. 2021, 2, 29.
DOI Google Scholar
[14]

Luan, B. Q.; Peng, H. B.; Polonsky, S.; Rossnagel, S.; Stolovitzky, G.; Martyna, G. Base-by-base ratcheting of single stranded DNA through a solid-state nanopore. Phys. Rev. Lett. 2010, 104, 238103.
DOI Google Scholar
[15]

Paik, K. H.; Liu, Y.; Tabard-Cossa, V.; Waugh, M. J.; Huber, D. E.; Provine, J.; Howe, R. T.; Dutton, R. W.; Davis, R. W. Control of DNA capture by nanofluidic transistors. ACS Nano 2012, 6, 6767–6775.
DOI Google Scholar
[16]

Nam, S. W.; Rooks, M. J.; Kim, K. B.; Rossnagel, S. M. Ionic field effect transistors with sub-10 nm multiple nanopores. Nano Lett. 2009, 9, 2044–2048.
DOI Google Scholar
[17]

Freedman, K. J.; Otto, L. M.; Ivanov, A. P.; Barik, A.; Oh, S. H.; Edel, J. B. Nanopore sensing at ultra-low concentrations using single-molecule dielectrophoretic trapping. Nat. Commun. 2016, 7, 10217.
DOI Google Scholar
[18]

Xie, P.; Xiong, Q. H.; Fang, Y.; Qing, Q.; Lieber, C. M. Local electrical potential detection of DNA by nanowire-nanopore sensors. Nat. Nanotechnol. 2012, 7, 119–125.
DOI Google Scholar
[19]

Traversi, F.; Raillon, C.; Benameur, S. M.; Liu, K.; Khlybov, S.; Tosun, M.; Krasnozhon, D.; Kis, A.; Radenovic, A. Detecting the translocation of DNA through a nanopore using graphene nanoribbons. Nat. Nanotechnol. 2013, 8, 939–945.
DOI Google Scholar
[20]

Heerema, S. J.; Vicarelli, L.; Pud, S.; Schouten, R. N.; Zandbergen, H. W.; Dekker, C. Probing DNA translocations with inplane current signals in a graphene nanoribbon with a nanopore. ACS Nano 2018, 12, 2623–2633.
DOI Google Scholar
[21]

Graf, M.; Lihter, M.; Altus, D.; Marion, S.; Radenovic, A. Transverse detection of DNA using a MoS2 nanopore. Nano Lett. 2019, 19, 9075–9083.
DOI Google Scholar
[22]

Zhu, X.; Li, X. J.; Gu, C. M.; Ye, Z.; Cao, Z.; Zhang, X. Y.; Jin, C. H.; Liu, Y. Monolithic integration of vertical thin-film transistors in nanopores for charge sensing of single biomolecules. ACS Nano 2021, 15, 9882–9889.
DOI Google Scholar
[23]

Ivanov, A. P.; Instuli, E.; McGilvery, C. M.; Baldwin, G.; McComb, D. W.; Albrecht, T.; Edel, J. B. DNA tunneling detector embedded in a nanopore. Nano Lett. 2011, 11, 279–285.
DOI Google Scholar
[24]

Ivanov, A. P.; Freedman, K. J.; Kim, M. J.; Albrecht, T.; Edel, J. B. High precision fabrication and positioning of nanoelectrodes in a nanopore. ACS Nano 2014, 8, 1940–1948.
DOI Google Scholar
[25]

Fanget, A.; Traversi, F.; Khlybov, S.; Granjon, P.; Magrez, A.; Forró, L.; Radenovic, A. Nanopore integrated nanogaps for DNA detection. Nano Lett. 2014, 14, 244–249.
DOI Google Scholar
[26]

Tsutsui, M.; Rahong, S.; Iizumi, Y.; Okazaki, T.; Taniguchi, M.; Kawai, T. Single-molecule sensing electrode embedded in-plane nanopore. Sci. Rep. 2011, 1, 46.
DOI Google Scholar
[27]

Tang, L. H.; Nadappuram, B. P.; Cadinu, P.; Zhao, Z. Y.; Xue, L.; Yi, L.; Ren, R.; Wang, J. W.; Ivanov, A. P.; Edel, J. B. Combined quantum tunnelling and dielectrophoretic trapping for molecular analysis at ultra-low analyte concentrations. Nat. Commun. 2021, 12, 913.
DOI Google Scholar
[28]

Cecchini, M. P.; Wiener, A.; Turek, V. A.; Chon, H.; Lee, S.; Ivanov, A. P.; McComb, D. W.; Choo, J.; Albrecht, T.; Maier, S. A. et al. Rapid ultrasensitive single particle surface-enhanced Raman spectroscopy using metallic nanopores. Nano Lett. 2013, 13, 4602–4609.
DOI Google Scholar
[29]

Freedman, K. J.; Crick, C. R.; Albella, P.; Barik, A.; Ivanov, A. P.; Maier, S. A.; Oh, S. H.; Edel, J. B. On-demand surface- and tip-enhanced Raman spectroscopy using dielectrophoretic trapping and nanopore sensing. ACS Photonics 2016, 3, 1036–1044.
DOI Google Scholar
[30]

Shi, X.; Gao, R.; Ying, Y. L.; Si, W.; Chen, Y. F.; Long, Y. T. A scattering nanopore for single nanoentity sensing. ACS Sens. 2016, 1, 1086–1090.
DOI Google Scholar
[31]

Verschueren, D. V.; Pud, S.; Shi, X.; de Angelis, L.; Kuipers, L.; Dekker, C. Label-free optical detection of DNA translocations through plasmonic nanopores. ACS Nano 2019, 13, 61–70.
DOI Google Scholar
[32]

Shi, X.; Verschueren, D. V.; Dekker, C. Active delivery of single DNA molecules into a plasmonic nanopore for label-free optical sensing. Nano Lett. 2018, 18, 8003–8010.
DOI Google Scholar
[33]

Chang, S.; He, J.; Kibel, A.; Lee, M.; Sankey, O.; Zhang, P. M.; Lindsay S. Tunnelling readout of hydrogen-bonding-based recognition. Nat. Nanotechnol. 2009, 4, 297–301.
DOI Google Scholar
[34]

Parkin, W. M.; Drndić, M. Signal and noise in FET-nanopore devices. ACS Sens. 2018, 3, 313–319.
DOI Google Scholar
[35]

Healy, K.; Ray, V.; Willis, L. J.; Peterman, N.; Bartel, J.; Drndić, M. Fabrication and characterization of nanopores with insulated transverse nanoelectrodes for DNA sensing in salt solution. Electrophoresis 2012, 33, 3488–3496.
DOI Google Scholar
[36]

Fried, J. P.; Swett, J. L.; Bian, X. Y.; Mol, J. A. Challenges in fabricating graphene nanodevices for electronic DNA sequencing. MRS Commun. 2018, 8, 703–711.
DOI Google Scholar
[37]

Kwok, H.; Briggs, K.; Tabard-Cossa, V. Nanopore fabrication by controlled dielectric breakdown. PLoS One 2014, 9, e92880.
DOI Google Scholar
[38]

Waugh, M.; Briggs, K.; Gunn, D.; Gibeault, M.; King, S.; Ingram, Q.; Jimenez, A. M.; Berryman, S.; Lomovtsev, D.; Andrzejewski, L. et al. Solid-state nanopore fabrication by automated controlled breakdown. Nat. Protoc. 2020, 15, 122–143.
DOI Google Scholar
[39]

Fried, J. P.; Swett J. L.; Nadappuram, B. P.; Mol, J. A.; Edel, J. B.; Ivanov, A. P.; Yates, J. R. In situ solid-state nanopore fabrication. Chem. Soc. Rev. 2021, 50, 4974–4992.
DOI Google Scholar
[40]

Leung, C.; Briggs, K.; Laberge, M. P.; Peng, S.; Waugh, M.; V. Tabard-Cossa. Mechanisms of solid-state nanopore enlargement under electrical stress. Nanotechnology 2020, 31, 44LT01.
DOI Google Scholar
[41]

Zrehen, A.; Gilboa, T.; Meller, A. Real-time visualization and sub-diffraction limit localization of nanometer-scale pore formation by dielectric breakdown. Nanoscale 2017, 9, 16437–16445.
DOI Google Scholar
[42]

Zhang, Y. N.; Miyahara, Y.; Derriche, N.; Yang, W.; Yazda, K.; Capaldi, X.; Liu, Z. Z.; Grutter, P.; Reisner, W. Nanopore formation via Tip-controlled local breakdown using an atomic force microscope. Small Methods 2019, 3, 1900147.
DOI Google Scholar
[43]

Yazda, K.; Bleau, K.; Zhang, Y. N.; Capaldi, X.; St-Denis, T.; Grutter, P.; Reisner, W. W. High osmotic power generation via nanopore arrays in hybrid hexagonal boron nitride/silicon nitride membranes. Nano Lett. 2021, 21, 4152–4159.
DOI Google Scholar
[44]

Carlsen, A. T.; Briggs, K.; Hall, A. R.; Tabard-Cossa, V. Solid-state nanopore localization by controlled breakdown of selectively thinned membranes. Nanotechnology 2017, 28, 085304.
DOI Google Scholar
[45]

Arcadia, C. E.; Reyes, C. C.; Rosenstein, J. K. In situ nanopore fabrication and single-molecule sensing with microscale liquid contacts. ACS Nano 2017, 11, 4907–4915.
DOI Google Scholar
[46]

Yin, B. H.; Fang, S. X.; Zhou, D. M.; Liang, L. Y.; Wang, L.; Wang, Z. B.; Wang, D. Q.; Yuan, J. H. Nanopore fabrication via transient high electric field controlled breakdown and detection of single RNA molecules. ACS Appl. Bio Mate. 2020, 3, 6368–6375.
DOI Google Scholar
[47]

Tahvildari, R.; Beamish, E.; Tabard-Cossa, V.; Godin, M. Integrating nanopore sensors within microfluidic channel arrays using controlled breakdown. Lab Chip 2015, 15, 1407–1411.
DOI Google Scholar
[48]

Spitzberg, J. D.; van Kooten, X. F.; Bercovici, M.; Meller, A. Microfluidic device for coupling isotachophoretic sample focusing with nanopore single-molecule sensing. Nanoscale 2020, 12, 17805–17811.
DOI Google Scholar
[49]

St-Denis, T.; Yazda, K.; Capaldi, X.; Bustamante, J.; Safari, M.; Miyahara, Y.; Zhang, Y.; Grutter, P.; Reisner, W. An apparatus based on an atomic force microscope for implementing tip-controlled local breakdown. Rev. Sci. Instrum. 2019, 90, 123703.
DOI Google Scholar
[50]

Pud, S.; Verschueren, D.; Vukovic, N.; Plesa, C.; Jonsson, M. P.; Dekker, C. Self-aligned plasmonic nanopores by optically controlled dielectric breakdown. Nano Lett. 2015, 15, 7112–7117.
DOI Google Scholar
[51]

Fried, J. P.; Swett, J. L.; Nadappuram, B. P.; Fedosyuk, A.; Sousa, P. M.; Briggs, D. P.; Ivanov, A. P.; Edel, J. B.; Mol, J. A.; Yates, J. R. Understanding electrical conduction and nanopore formation during controlled breakdown. Small 2021, 17, 2102543.
DOI Google Scholar
[52]

Anderson, B. N.; Assad, O. N.; Gilboa, T.; Squires, A. H.; Bar, D.; Meller, A. Probing solid-state nanopores with light for the detection of unlabeled analytes. ACS Nano 2014, 8, 11836–11845.
DOI Google Scholar
[53]

Ivankin, A.; Henley, R. Y.; Larkin, J.; Carson, S.; Toscano, M. L.; Wanunu, M. Label-free optical detection of biomolecular translocation through nanopore arrays. ACS Nano 2014, 8, 10774–10781.
DOI Google Scholar
[54]

Kwok, H.; Waugh, M.; Bustamante, J.; Briggs, K.; Tabard-Cossa, V. Long passage times of short ssDNA molecules through metallized nanopores fabricated by controlled breakdown. Adv. Funct. Mater. 2014, 24, 7745–7753.
DOI Google Scholar
[55]

Beamish, E.; Kwok, H.; Tabard-Cossa, V.; Godin, M. Precise control of the size and noise of solid-state nanopores using high electric fields. Nanotechnology 2012, 23, 405301.
DOI Google Scholar
[56]

Kowalczyk, S. W.; Grosberg, A. Y.; Rabin, Y.; Dekker, C. Modeling the conductance and DNA blockade of solid-state nanopores. Nanotechnology 2011, 22, 315101.
DOI Google Scholar
[57]

Spitzberg, J. D.; Zrehen, A.; van Kooten, X. F.; Meller, A. Plasmonic-nanopore biosensors for superior single-molecule detection. Adv. Mater. 2019, 31, 1900422.
DOI Google Scholar
[58]

Garoli, D.; Yamazaki, H.; Maccaferri, N.; Wanunu, M. Plasmonic nanopores for single-molecule detection and manipulation: Toward sequencing applications. Nano Lett. 2019, 19, 7553–7562.
DOI Google Scholar
[59]

Bhat, A.; Gwozdz, P. V.; Seshadri, A.; Hoeft, M.; Blick, R. H. Tank circuit for ultrafast single-particle detection in micropores. Phys. Rev. Lett. 2018, 121, 078102.
DOI Google Scholar
[60]

Yanagi, I.; Takeda, K. I. Current-voltage characteristics of SiN membranes in solution. ACS Appl. Electron. Mater. 2020, 2, 2760–2771.
DOI Google Scholar
[61]

Gehring, P.; Thijssen, J. M.; van der Zant, H. S. J. Single-molecule quantum-transport phenomena in break junctions. Nat. Rev. Phys. 2019, 1, 381–396.
DOI Google Scholar
[62]

Perrin, M. L.; Burzurí, E.; van der Zant, H. S. J. Single-molecule transistors. Chem. Soc. Rev. 2015, 44, 902–919.
DOI Google Scholar
[63]

Hadeed, F. O.; Durkan, C. Controlled fabrication of 1−2 nm nanogaps by electromigration in gold and gold-palladium nanowires. Appl. Phys. Lett. 2007, 91, 123120.
DOI Google Scholar
[64]

Jeong, W.; Kim, K.; Kim, Y.; Lee, W.; Reddy, P. Characterization of nanoscale temperature fields during electromigration of nanowires. Sci. Rep. 2014, 4, 5690.
DOI Google Scholar
[65]

Briggs, K.; Kwok, H.; Tabard-Cossa, V. Automated fabrication of 2-nm solid-state nanopores for nucleic acid analysis. Small 2014, 10, 2077–2086.
DOI Google Scholar
[66]

Fragasso, A.; Schmid, S.; Dekker, C. Comparing current noise in biological and solid-state nanopores. ACS Nano 2020, 14, 1338–1349.
DOI Google Scholar
[67]

Chen, P.; Gu, J. J.; Brandin, E.; Kim, Y. R.; Wang, Q.; Branton, D. Probing single DNA molecule transport using fabricated nanopores. Nano Lett. 2004, 4, 2293–2298.
DOI Google Scholar
[68]

Grosberg, A. Y.; Rabin, Y. DNA capture into a nanopore: Interplay of diffusion and electrohydrodynamics. J. Chem. Phys. 2010, 133, 165102.
DOI Google Scholar
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Publication history

Received: 08 February 2022
Revised: 07 April 2022
Accepted: 11 May 2022
Published: 25 June 2022
Issue date: November 2022

Copyright

© The Author(s) 2022

Acknowledgements

The authors would like to thank Kevin Lester and Daryl Briggs for their assistance with preparing the wafers. J. P. F. thanks the Oxford Australia Scholarship committee and the University of Western Australia for funding. Substrate, membrane, and some electrode fabrication were conducted at the Center for Nanophase Materials Sciences, which is a DOE Office of Science User Facility. J. R. Y. was funded by an FCT contract according to DL57/2016, [SFRH/BPD/80071/2011]. Work in J. R. Y.’s lab was funded by national funds through FCT - Fundação para a Ciência e a Tecnologia, I. P., Project MOSTMICRO-ITQB with refs UIDB/04612/2020 and UIDP/04612/2020 and Project PTDC/NAN-MAT/31100/2017. J. M. was supported through the UKRI Future Leaders Fellowship, Grant No. MR/S032541/1, with in-kind support from the Royal Academy of Engineering. A. P. I. and J. B. E. acknowledge support from BBSRC grant BB/R022429/1, EPSCR grant EP/P011985/1, and Analytical Chemistry Trust Fund grant 600322/05. This project has also received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (Nos. 724300 and 875525). O. D. and STEM investigations were supported by the Center for Nanophase Materials Sciences (CNMS), a U.S. Department of Energy, Office of Science User Facility. The authors would like to thank Andrew Briggs for providing funding for some of the equipment and facilities used.

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