Sub-nanometre channels embedded in two-dimensional materials

Abstract

Two-dimensional (2D) materials are among the most promising candidates for next-generation electronics due to their atomic thinness, allowing for flexible transparent electronics and ultimate length scaling1. Thus far, atomically thin p–n junctions2,3,4,5,6,7,8, metal–semiconductor contacts9,10,11, and metal–insulator barriers12,13,14 have been demonstrated. Although 2D materials achieve the thinnest possible devices, precise nanoscale control over the lateral dimensions is also necessary. Here, we report the direct synthesis of sub-nanometre-wide one-dimensional (1D) MoS2 channels embedded within WSe2 monolayers, using a dislocation-catalysed approach. The 1D channels have edges free of misfit dislocations and dangling bonds, forming a coherent interface with the embedding 2D matrix. Periodic dislocation arrays produce 2D superlattices of coherent MoS2 1D channels in WSe2. Using molecular dynamics simulations, we have identified other combinations of 2D materials where 1D channels can also be formed. The electronic band structure of these 1D channels offers the promise of carrier confinement in a direct-gap material and the charge separation needed to access the ultimate length scales necessary for future electronic applications.

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Figure 1: Formation of 1D channels.
Figure 2: Strain maps of the 1D channels.
Figure 3: Molecular dynamics (MD) simulation of the 1D channel formation.
Figure 4: Generation of a superlattice at a grain boundary.

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Acknowledgements

The authors acknowledge discussions with M. Zhao, L. Wang, C. Zhen, M. Holtz, H.-S. Kim, C. Gong, T. Cao, M. S. Ramos, L. F. Kourkoutis, B. Savitzky, M. Zhao, C.-J. Kim, K. Kang, J. Park, D. Jena and J. Sethna. This work made use of the electron microscopy facility of the Cornell Center for Materials Research (CCMR) with support from the National Science Foundation (NSF) Materials Research Science and Engineering Centers (MRSEC) program (DMR-1120296) and NSF Major Research Instrumentation Program (DMR-1429155). Y.H. and D.M. were supported by NSF Grant (DMR-1719875) and DOD-MURI (Grant No. FA9550-16-1-0031). G.-S.J., Z.Q. and M.J.B. acknowledge support by the Office of Naval Research (Grant No. N00014-16-1-233) and DOD-MURI (Grant No. FA9550-15-1-0514). We acknowledge support for supercomputing resources from the Supercomputing Center/KISTI (KSC-2017-C2-0013). M.-Y.L. and L.L. thank the support from King Abdullah University of Science and Technology (KAUST) and Academia Sinica.

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Contributions

Y.H., M.-Y.L. and G.-S.J. contributed equally to this work. Y.H. conceived the project. Electron microscopy and data analysis were carried out by Y.H., under the supervision of D.A.M., with help from M.A.M. Sample growth was done by M.-Y.L., under the supervision of L.L. The molecular dynamics simulations and density function theory calculations were conducted by G.-S.J. and Z.Q., under the supervision of M.J.B.

Corresponding authors

Correspondence to Lain-Jong Li or David A. Muller.

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The authors declare no competing financial interests.

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Han, Y., Li, M., Jung, G. et al. Sub-nanometre channels embedded in two-dimensional materials. Nat. Mater. 17, 129–133 (2018). https://doi.org/10.1038/nmat5038

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