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Vertical, electrolyte-gated organic transistors show continuous operation in the MA cm−2 regime and artificial synaptic behaviour

Nature Nanotechnology (2019) | Download Citation


Until now, organic semiconductors have failed to achieve high performance in highly integrated, sub-100 nm transistors. Consequently, single-crystalline materials such as single-walled carbon nanotubes, MoS2 or inorganic semiconductors are the materials of choice at the nanoscale. Here we show, using a vertical field-effect transistor design with a channel length of only 40 nm and a footprint of 2 × 80 × 80 nm2, that high electrical performance with organic polymers can be realized when using electrolyte gating. Our organic transistors combine high on-state current densities of above 3 MA cm−2, on/off current modulation ratios of up to 108 and large transconductances of up to 5,000 S m−1. Given the high on-state currents at such large on/off ratios, our novel structures also show promise for use in artificial neural networks, where they could operate as memristive devices with sub-100 fJ energy usage.

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The raw data that support the plots within this paper and other findings of this study are provided in the Supplementary Information and are available from the authors upon reasonable request.

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Journal peer review information Nature Nanotechnology thanks Bjorn Lussem and the other anonymous reviewer(s) for their contribution to the peer review of this work.

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  1. 1.

    Cao, Q., Tersoff, J., Farmer, D. B., Zhu, Y. & Han, S.-J. Carbon nanotube transistors scaled to a 40-nanometer footprint. Science 356, 1369–1372 (2017).

  2. 2.

    Si, M. et al. Steep-slope hysteresis-free negative capacitance MoS2 transistors. Nat. Nanotechnol. 13, 24–28 (2018).

  3. 3.

    Cao, Q. et al. Arrays of single-walled carbon nanotubes with full surface coverage for high-performance electronics. Nat. Nanotechnol. 8, 180–186 (2013).

  4. 4.

    Zschieschang, U., Letzkus, F., Burghartz, J. N. & Klauk, H. Parameter uniformity of submicron-channel-length organic thin-film transistors fabricated by stencil lithography. IEEE Trans. Nanotechnol. 16, 837–841 (2017).

  5. 5.

    Klinger, M. P. et al. Organic power electronics: transistor operation in the kA/cm2 regime. Sci. Rep. 7, 44713 (2017).

  6. 6.

    Bijleveld, J. C. et al. Poly(diketopyrrolopyrrole-terthiophene) for ambipolar logic and photovoltaics. J. Am. Chem. Soc. 131, 16616–16617 (2009).

  7. 7.

    Ono, S., Seki, S., Hirahara, R., Tominari, Y. & Takeya, J. High-mobility, low-power, and fast-switching organic field-effect transistors with ionic liquids. Appl. Phys. Lett. 92, 103313 (2008).

  8. 8.

    Cho, J. H. et al. High-capacitance ion gel gate dielectrics with faster polarization response times for organic thin film transistors. Adv. Mater. 20, 686–690 (2008).

  9. 9.

    Kettner, M., Vladimirov, I., Strudwick, A. J., Schwab, M. G. & Weitz, R. T. Ionic gel as gate dielectric for the easy characterization of graphene and polymer field-effect transistors and electrochemical resistance modification of graphene. J. Appl. Phys. 118, 25501 (2015).

  10. 10.

    Panzer, M. J. & Frisbie, C. D. Polymer electrolyte-gated organic field-effect transistors: low-voltage, high-current switches for organic electronics and testbeds for probing electrical transport at high charge carrier density. J. Am. Chem. Soc. 129, 6599–6607 (2007).

  11. 11.

    Panzer, M. J., Newman, C. R. & Frisbie, C. D. Low-voltage operation of a pentacene field-effect transistor with a polymer electrolyte gate dielectric. Appl. Phys. Lett. 86, 103503 (2005).

  12. 12.

    Herlogsson, L. et al. Downscaling of organic field-effect transistors with a polyelectrolyte gate insulator. Adv. Mater. 20, 4708–4713 (2008).

  13. 13.

    Klauk, H. Will we see gigahertz organic transistors? Adv. Electron. Mater. 4, 1700474 (2018).

  14. 14.

    Braga, D., Ha, M., Xie, W. & Frisbie, C. D. Ultralow contact resistance in electrolyte-gated organic thin film transistors. Appl. Phys. Lett. 97, 193311 (2010).

  15. 15.

    Khodagholy, D. et al. High transconductance organic electrochemical transistors. Nat. Commun. 4, 2133 (2013).

  16. 16.

    Bucella, S. G. et al. Macroscopic and high-throughput printing of aligned nanostructured polymer semiconductors for MHz large-area electronics. Nat. Commun. 6, 8394 (2015).

  17. 17.

    Lüssem, B., Günther, A., Fischer, A., Kasemann, D. & Leo, K. Vertical organic transistors. J. Phys. Condens. Matter 27, 443003 (2015).

  18. 18.

    Li, S.-H., Xu, Z., Yang, G., Ma, L. & Yang, Y. Solution-processed poly(3-hexylthiophene) vertical organic transistor. Appl. Phys. Lett. 93, 213301 (2008).

  19. 19.

    Stutzmann, N., Friend, R. H. & Sirringhaus, H. Self-aligned, vertical-channel, polymer field-effect transistors. Science 299, 1881–1884 (2003).

  20. 20.

    Rother, M. et al. Vertical electrolyte-gated transistors based on printed single-walled carbon nanotubes. ACS Appl. Nano Mater. 1, 3616–3624 (2018).

  21. 21.

    Huang, K.-M. et al. 2-V operated flexible vertical organic transistor with good air stability and bias stress reliability. Org. Electron. 50, 325–330 (2017).

  22. 22.

    Johnston, D. E., Yager, K. G., Nam, C.-Y., Ocko, B. M. & Black, C. T. One-volt operation of high-current vertical channel polymer semiconductor field-effect transistors. Nano Lett. 12, 4181–4186 (2012).

  23. 23.

    Liu, Y. et al. High-current-density vertical-tunneling transistors from graphene/highly doped silicon heterostructures. Adv. Mater. 28, 4120–4125 (2016).

  24. 24.

    Wilbers, J. G. E., Xu, B., Bobbert, P. A., Jong, M. P. de & van der Wiel. Wilfred G. Charge transport in nanoscale vertical organic semiconductor pillar devices. Sci. Rep. 7, 41171 (2017).

  25. 25.

    Greenman, M. et al. Reaching saturation in patterned source vertical organic field effect transistors. J. Appl. Phys. 121, 204503 (2017).

  26. 26.

    Mo, Y. G. et al. Amorphous-oxide TFT backplane for large-sized AMOLED TVs. J. Soc. Inf. Display 19, 16 (2011).

  27. 27.

    Roy, K., Mukhopadhyay, S. & Mahmoodi-Meimand, H. Leakage current mechanisms and leakage reduction techniques in deep-submicrometer CMOS circuits. Proc. IEEE 91, 305–327 (2003).

  28. 28.

    Kim, S. H., Hong, K., Lee, K. H. & Frisbie, C. D. Performance and stability of aerosol-jet-printed electrolyte-gated transistors based on poly(3-hexylthiophene). ACS Appl. Mater. Interfaces 5, 6580–6585 (2013).

  29. 29.

    van de Burgt, Y., Melianas, A., Keene, S. T., Malliaras, G. & Salleo, A. Organic electronics for neuromorphic computing. Nat. Electron. 1, 386–397 (2018).

  30. 30.

    Weitz, R. T., Walter, A., Engl, R., Sezi, R. & Dehm, C. New charge-transfer salts for reversible resistive memory switching. Nano Lett. 6, 2810–2813 (2006).

  31. 31.

    Gkoupidenis, P., Schaefer, N., Garlan, B. & Malliaras, G. G. Neuromorphic functions in PEDOT:PSS organic electrochemical transistors. Adv. Mater. 27, 7176–7180 (2015).

  32. 32.

    Yang, Y. et al. Long-term synaptic plasticity emulated in modified graphene oxide electrolyte gated IZO-based thin-film transistors. ACS Appl. Mater. Interfaces 8, 30281–30286 (2016).

  33. 33.

    van de Burgt, Y. et al. A non-volatile organic electrochemical device as a low-voltage artificial synapse for neuromorphic computing. Nat. Mater. 16, 414–418 (2017).

  34. 34.

    Peng, Y., Cullis, T. & Inkson, B. Accurate electrical testing of individual gold nanowires by in situ scanning electron microscope nanomanipulators. Appl. Phys. Lett. 93, 183112 (2008).

  35. 35.

    Hayyan, M., Mjalli, F. S., Hashim, M. A., AlNashef, I. M. & Mei, T. X. Investigating the electrochemical windows of ionic liquids. J. Ind. Eng. Chem. 19, 106–112 (2013).

  36. 36.

    Gao, G. B., Fan, Z. F. & Morkoç, H. Negative output differential resistance in AlGaAs/GaAs heterojunction bipolar transistors. Appl. Phys. Lett. 61, 198–200 (1992).

  37. 37.

    Klinger, M. P., Fischer, A., Kleemann, H. & Leo, K. Non-linear self-heating in organic transistors reaching high power densities. Sci. Rep. 8, 9806 (2018).

  38. 38.

    Yu, F. et al. Vertical architecture for enhancement mode power transistors based on GaN nanowires. Appl. Phys. Lett. 108, 213503 (2016).

  39. 39.

    Yu, W. J. et al. Vertically stacked multi-heterostructures of layered materials for logic transistors and complementary inverters. Nat. Mater. 12, 246–252 (2013).

  40. 40.

    Seo, K.-I. et al. A 10 nm platform technology for low power and high performance application featuring FINFET devices with multi workfunction gate stack on bulk and SOI. Proc. 2014 Symposium on VLSI Technology 1–2 (2014).

  41. 41.

    Donahue, M. J. et al. High-performance vertical organic electrochemical transistors. Adv. Mater. 30, 1705031 (2018).

  42. 42.

    Wu, G. et al. Artificial synaptic devices based on natural chicken albumen coupled electric-double-layer transistors. Sci. Rep. 6, 23578 (2016).

  43. 43.

    Xu, W., Min, S.-Y., Hwang, H. & Lee, T.-W. Organic core–sheath nanowire artificial synapses with femtojoule energy consumption. Sci. Adv. 2, e1501326 (2016).

  44. 44.

    Samuel, I. D. W. & Turnbull, G. A. Organic semiconductor lasers. Chem. Rev. 107, 1272–1295 (2007).

  45. 45.

    Hayashi, K. et al. Suppression of roll-off characteristics of organic light-emitting diodes by narrowing current injection/transport area to 50 nm. Appl. Phys. Lett. 106, 93301 (2015).

  46. 46.

    Kim, S. H. et al. Electrolyte-gated transistors for organic and printed electronics. Adv. Mater. 25, 1822–1846 (2013).

  47. 47.

    Choi, J.-H. et al. High capacitance, photo-patternable ion gel gate insulators compatible with vapor deposition of metal gate electrodes. ACS Appl. Mater. Interfaces 6, 19275–19281 (2014).

  48. 48.

    McCarthy, M. A., Liu, B. & Rinzler, A. G. High current, low voltage carbon nanotube enabled vertical organic field effect transistors. Nano Lett. 10, 3467–3472 (2010).

  49. 49.

    Kleemann, H., Günther, A. A., Leo, K. & Lüssem, B. High-performance vertical organic transistors. Small 9, 3670–3677 (2013).

  50. 50.

    Fischer, A., Scholz, R., Leo, K. & Lüssem, B. An all C60vertical transistor for high frequency and high current density applications. Appl. Phys. Lett. 101, 213303 (2012).

  51. 51.

    Yang, C.-Y. et al. Vertical organic triodes with a high current gain operated in saturation region. Appl. Phys. Lett. 89, 183511 (2006).

  52. 52.

    Fukagawa, H. et al. High-current operation of vertical-type organic transistor with preferentially oriented molecular film. AIP Adv. 6, 45010 (2016).

  53. 53.

    Watanabe, Y., Iechi, H. & Kudo, K. Improvement in on/off ratio of pentacene static induction transistors with ultrathin CuPc layer. Jpn J. Appl. Phys. 45, 3698–3703 (2006).

  54. 54.

    Chao, Y.-C. et al. Polymer space-charge-limited transistor as a solid-state vacuum tube triode. Appl. Phys. Lett. 97, 223307 (2010).

  55. 55.

    Qiu, C. et al. Dirac-source field-effect transistors as energy-efficient, high-performance electronic switches. Science 361, 387–392 (2018).

  56. 56.

    Zan, H.-W. et al. High output current in vertical polymer space-charge-limited transistor induced by self-assembled monolayer. Appl. Phys. Lett. 101, 93307 (2012).

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The authors thank BASF SE for supplying the organic semiconductors and liquid electrolytes. The authors acknowledge partial support by the ‘Solar Technologies go Hybrid’ (SolTech) initiative, the Center for Nanoscience (CeNS) and the Nanosystems Initiative Munich (NIM).

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Author notes

    • Fabio del Giudice

    Present address: Walter-Schottky Institute, Technical University Munich, Garching, Germany


  1. Physics of Nanosystems, Department of Physics, Ludwig-Maximilians-Universität München, Munich, Germany

    • Jakob Lenz
    • , Fabio del Giudice
    • , Fabian R. Geisenhof
    • , Felix Winterer
    •  & R. Thomas Weitz
  2. Nanosystems Initiative Munich (NIM), Munich, Germany

    • R. Thomas Weitz
  3. Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, Munich, Germany

    • R. Thomas Weitz


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J.L. and R.T.W conceived the project. J.L. prepared the VOFET samples and conducted the measurements and data analysis. F.d.G prepared the lateral transistor samples and conducted the measurements and data analysis. All authors discussed the data. J.L. and R.T.W. wrote the manuscript with input from all authors. R.T.W. supervised the project.

Competing interests

J.L. and R.T.W. have submitted a patent application to the German patent office (no. 10 2018 221 361.5) covering the structure of the VOFET and the applications discussed in this manuscript.

Corresponding author

Correspondence to R. Thomas Weitz.

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