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Making clean electrical contacts on 2D transition metal dichalcogenides

Nature Reviews Physics volume 4, pages 101–112 (2022)Cite this article

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Abstract

2D semiconductors, particularly transition metal dichalcogenides (TMDs), have emerged as highly promising for new electronic technologies. However, a key challenge in fabricating devices out of 2D semiconductors is the need for ultra-clean contacts with resistances approaching the quantum limit. The lack of high-quality, low-contact-resistance P-type and N-type contacts on 2D TMDs has limited progress towards the next generation of low-power devices, such as the tunnel field-effect transistors. In this Expert Recommendation, we summarize strategies and provide guidance for making clean van der Waals contacts on monolayered TMD semiconductors. We also discuss the physics of contacts in 2D semiconductors and prospects for achieving quantum conductance.

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Fig. 1: Band energy diagrams of metal–semiconductor junctions under thermal equilibrium.
Fig. 2: Mechanisms responsible for Fermi-level pinning in metal–2D TMD semiconductor junctions.
Fig. 3: Contact resistance versus carrier concentration for monolayer MoS2 with different contacts and varying size of van der Waals gap.

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Acknowledgements

The authors acknowledge funding from Royal Society Wolfson Research Merit Award (WRM\FT\180009), Leverhulme Trust grant RPG-2019-227 and EPSRC grants EP/T026200/1 and EP/T001038/1.

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  1. Department of Materials Science & Metallurgy, University of Cambridge, Cambridge, UK

    Yan Wang & Manish Chhowalla

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  1. Yan Wang
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Y.W. and M.C. wrote and edited this paper.

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Correspondence to Manish Chhowalla.

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Wang, Y., Chhowalla, M. Making clean electrical contacts on 2D transition metal dichalcogenides. Nat Rev Phys 4, 101–112 (2022). https://doi.org/10.1038/s42254-021-00389-0

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