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Coplanar semiconductor–metal circuitry defined on few-layer MoTe2 via polymorphic heteroepitaxy

Nature Nanotechnology volume 12, pages 1064–1070 (2017)Cite this article

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Abstract

Crystal polymorphism selectively stabilizes the electronic phase of atomically thin transition-metal dichalcogenides (TMDCs) as metallic or semiconducting, suggesting the potential to integrate these polymorphs as circuit components in two-dimensional electronic circuitry. Developing a selective and sequential growth strategy for such two-dimensional polymorphs in the vapour phase is a critical step in this endeavour. Here, we report on the polymorphic integration of distinct metallic (1T′) and semiconducting (2H) MoTe2 crystals within the same atomic planes by heteroepitaxy. The realized polymorphic coplanar contact is atomically coherent, and its barrier potential is spatially tight-confined over a length of only a few nanometres, with a lowest contact barrier height of ∼25 meV. We also demonstrate the generality of our synthetic integration approach for other TMDC polymorph films with large areas.

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Figure 1: Polymorphic integration of few-layer 1T′/2H MoTe2 crystals within the same atomic planes by sequential lateral heteroepitaxy.
Figure 2: Atomic-scale crystal and electronic structures of 2H and 1T′-MoTe2 polymorphs.
Figure 3: Electrical properties of the coplanar 1T′/2H MoTe2 polymorph transistor.
Figure 4: Multi-terminal 1T′/2H-MoTe2 polymorphic FETs.
Figure 5: Comparison of the polymorphic 1T′-coplanar and Au-top contacts to 2H-MoTe2 atomic layers.
Figure 6: Synthetic integration of 2H-WSe2/1T′-WTe2 polymorph films in large areas.

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Acknowledgements

This work was supported by the Institute for Basic Science (IBS), Korea, under project code IBS-R014-A1. J.S.K. was also supported by the NRF through the SRC Center for Topological Matter (grant no. 2011-0030046) and the Max Planck POSTECH/KOREA Research Initiative Program (grant no. 2011-0031558).

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Author notes

  1. Ji Ho Sung, Hoseok Heo and Saerom Si: These authors contributed equally to this work.

Authors and Affiliations

  1. Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, 37673, Korea

    Ji Ho Sung, Hoseok Heo, Saerom Si, Yong Hyeon Kim, Hyeong Rae Noh, Juho Kim, Chang-Soo Lee, Seung-Young Seo, Dong-Hwi Kim, Hyoung Kug Kim, Han Woong Yeom, Tae-Hwan Kim, Jun Sung Kim & Moon-Ho Jo

  2. Division of Advanced Materials Science, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Korea

    Ji Ho Sung, Hoseok Heo & Moon-Ho Jo

  3. Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Korea

    Saerom Si, Juho Kim, Chang-Soo Lee, Seung-Young Seo, Dong-Hwi Kim, Si-Young Choi & Moon-Ho Jo

  4. Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Korea

    Yong Hyeon Kim, Hyeong Rae Noh, Hyoung Kug Kim, Han Woong Yeom, Tae-Hwan Kim & Jun Sung Kim

  5. Department of Materials Modeling & Characterization, Korea Institute of Materials Science, Changwon, 51508, Korea

    Kyung Song & Si-Young Choi

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Contributions

M.-H.J. and H.H. conceived and designed the project. S.S., H.H. and C.-S.L. synthesized MoTe2 polymorphs and carried out the AFM and Raman scattering characterizations. J.H.S., Y.H.K., J.K., S.-Y.S. and D.-H.K. performed device fabrication and electrical characterization. H.R.N., H.K.K. and H.W.Y. performed STM measurements. K.S. and S.-Y.C. acquired STEM images and analysed the data. M.-H.J., J.S.K., T.-H.K., S.-Y.C., J.H.S. and H.H. co-wrote the paper. All the authors discussed the results and commented on the manuscript.

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Correspondence to Moon-Ho Jo.

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Sung, J., Heo, H., Si, S. et al. Coplanar semiconductor–metal circuitry defined on few-layer MoTe2 via polymorphic heteroepitaxy. Nature Nanotech 12, 1064–1070 (2017). https://doi.org/10.1038/nnano.2017.161

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