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High-performance flexible nanoscale transistors based on transition metal dichalcogenides

Abstract

Two-dimensional (2D) semiconducting transition metal dichalcogenides could be used to build high-performance flexible electronics. However, flexible field-effect transistors (FETs) based on such materials are typically fabricated with channel lengths on the micrometre scale, not benefitting from the short-channel advantages of 2D materials. Here, we report flexible nanoscale FETs based on 2D semiconductors; these are fabricated by transferring chemical-vapour-deposited transition metal dichalcogenides from rigid growth substrates together with nano-patterned metal contacts, using a polyimide film, which becomes the flexible substrate after release. Transistors based on monolayer molybdenum disulfide (MoS2) are created with channel lengths down to 60 nm and on-state currents up to 470 μA μm−1 at a drain–source voltage of 1 V, which is comparable to the performance of flexible graphene and crystalline silicon FETs. Despite the low thermal conductivity of the flexible substrate, we find that heat spreading through the metal gate and contacts is essential to reach such high current densities. We also show that the approach can be used to create flexible FETs based on molybdenum diselenide (MoSe2) and tungsten diselenide (WSe2).

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Fig. 1: Transfer process for 2D monolayers with contacts.
Fig. 2: Flexible FETs with TMDs.
Fig. 3: Nanoscale MoS2 FETs.
Fig. 4: Benchmarking flexible FETs.

Data availability

The data that support the plots within this paper and other findings of the study are available from the corresponding author upon reasonable request.

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Acknowledgements

A.D. is in part supported by the Swiss National Science Foundation’s Early Postdoc.Mobility fellowship (grant no. P2EZP2_181619) and in part by Beijing Institute of Collaborative Innovation (BICI). R.W.G., C.S.B. and K.S. acknowledge the National Science Foundation (NSF) Graduate Research Fellowship. K.S. also acknowledges support from the Stanford Graduate Fellowship. We thank the Stanford Nanofabrication Facility and Stanford Nano Shared Facilities for enabling device fabrication and characterization, funded under NSF award no. ECCS-1542152. E.P. and S.V. acknowledge support from the Stanford SystemX Alliance.

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Contributions

A.D. conceived the work and performed the device fabrication and characterization. A.D. and S.V. developed the TMD transfer process. R.W.G. performed the MoS2 CVD growth and C.S.B. the WSe2 and MoSe2 CVD growths. V.C. carried out the electron beam lithography and atomic-force microscopy. A.D. and K.S. performed optical material analysis with help from K.B. H.R.L. carried out scanning electron microscopy. C.K. set up numerical current spreading simulations and thermal simulations with E.P. A.D. analysed all data and wrote the manuscript with help from V.C., C.K. and E.P. All authors revised and commented on the manuscript. E.P. supervised the work.

Corresponding author

Correspondence to Eric Pop.

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Peer review information Nature Electronics thanks Henry Medina and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Supplementary Information

Supplementary sections 1–17 with Supplementary Discussion, Figs. 1–25, Tables 1–3 and additional references 59–104.

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Daus, A., Vaziri, S., Chen, V. et al. High-performance flexible nanoscale transistors based on transition metal dichalcogenides. Nat Electron 4, 495–501 (2021). https://doi.org/10.1038/s41928-021-00598-6

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