Two-dimensional semiconductors, such as molybdenum disulfide (MoS2), exhibit a variety of properties that could be useful in the development of novel electronic devices. However, nanopatterning metal electrodes on such atomic layers, which is typically achieved using electron beam lithography, is currently problematic, leading to non-ohmic contacts and high Schottky barriers. Here, we show that thermal scanning probe lithography can be used to pattern metal electrodes with high reproducibility, sub-10-nm resolution, and high throughput (105 μm2 h−1 per single probe). The approach, which offers simultaneous in situ imaging and patterning, does not require a vacuum, high energy, or charged beams, in contrast to electron beam lithography. Using this technique, we pattern metal electrodes in direct contact with monolayer MoS2 for top-gate and back-gate field-effect transistors. These devices exhibit vanishing Schottky barrier heights (around 0 meV), on/off ratios of 1010, no hysteresis, and subthreshold swings as low as 64 mV per decade without using negative capacitors or hetero-stacks.
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The data that support the plots within this paper and other findings of this study are available from the corresponding authors upon reasonable request.
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The authors acknowledge support from the US Army Research Office (proposal number 69180-CH), the Office of Basic Energy Sciences of the US Department of Energy, the National Science Foundation, SwissLitho, and the European Union’s Horizon 2020 research and innovation programme under grant agreement number 705326 (project SWING). A.S.M.A. and D.S. acknowledge financial support from NSF-ECCS (grant number 1638598).
The authors declare no competing interests.
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Supplementary Sections 1–15, Supplementary Figures 1–24, and Supplementary Tables 1–3.
Real-time screenshot recording acquired during the patterning process on PPA, from the writing of the large pads (10 × 10 µm2 squares) to the small fingers (1.5 µm wide) lying on top of a monolayer CVD MoS2 flake. The number of frames is 81,258 (29 frames per second).
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Zheng, X., Calò, A., Albisetti, E. et al. Patterning metal contacts on monolayer MoS2 with vanishing Schottky barriers using thermal nanolithography. Nat Electron 2, 17–25 (2019). https://doi.org/10.1038/s41928-018-0191-0
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