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

Abstract

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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Fig. 1: Planar, electrolyte-gated nanoscopic PDPP OFETs.
Fig. 2: Device fabrication process of electrolyte gated VOFETs.
Fig. 3: Electrical characteristics of electrolyte-gated PDPP VOFET measured in ambient atmosphere.
Fig. 4: Nanoscopic electrolyte-gated PDPP VOFET measured in ambient atmosphere and comparison to state-of-the-art transistors.
Fig. 5: Short- and long-term synaptic plasticity of electrolyte-gated PDPP VOFETs measured in ambient atmosphere.

Data availability

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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Acknowledgements

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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Authors

Contributions

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.

Corresponding author

Correspondence to R. Thomas Weitz.

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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.

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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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Lenz, J., del Giudice, F., Geisenhof, F.R. et al. Vertical, electrolyte-gated organic transistors show continuous operation in the MA cm−2 regime and artificial synaptic behaviour. Nat. Nanotechnol. 14, 579–585 (2019). https://doi.org/10.1038/s41565-019-0407-0

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