Abstract
Achieving high-quality source/drain contacts in two-dimensional (2D) semiconductors remains challenging due to Fermi-level pinning induced by metal-induced gap states (MIGS). Here, we demonstrate an atomically sharp Hf2C/HfSe2 edge contact formed via a laterally directed chemical conversion, driven by catalyst-assisted hydrodeselenization and carbonization under epitaxial alignment. Classical and ab initio molecular dynamics elucidate the atomistic mechanism of heteroepitaxial interface formation. Scanning tunneling microscopy and spectroscopy measurements confirm suppressed MIGS at the heteroepitaxial interface, indicating an electronically transparent junction. Electrical measurements reveal a near-zero Schottky barrier height ( ≈ 5 meV) and reduced contact resistance ( ≈ 475 Ω·μm) when compared with previously reported 2D edge-contact systems. When co-integrated with a van der Waals-integrated native high-κ HfO2 gate dielectric within a single HfSe2 channel, the devices exhibit a subthreshold swing of 62 mV/dec and on-state current density of 920 μA/μm. This integrated platform establishes a scalable design framework that couples contact and gate-stack engineering for next-generation 2D logic technologies.
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Acknowledgements
This research was supported by the Basic Science Research Program through the National Research Foundation of Korea and was funded by the Korean Government (MSIP) (Grant Nos. RS-2023-00281048 and RS-2025-00512822). This work was supported by Samsung Research Funding & Incubation Center of Samsung Electronics under Project Number SRFC-MA2501-01. This study was supported by Samsung Electronics Co. Ltd (IO251217-14774-01).
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G.B. and T.K. conceived and designed the experiments. G.B. and T.K. prepared the materials, characterized the samples, fabricated the devices, and performed the electrical characterization with assistance from S.Y.L. and C.Y.P. J.-S.P. performed the first principles and ab initio molecular dynamics simulations and contributed to the mechanistic interpretation of the interface reactions. J.W.J. conducted the STM/STS analysis, and S.J. carried out the KPFM measurements. Y.J.S. supervised the STM/STS and KPFM analyses. S.O. and J.H.L. performed the device simulations and assisted in analyzing the electrical characteristics. S.L., G.B., and T.K. analyzed the data and co-wrote the manuscript with input from all authors. S.L. supervised the overall project.
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Bhin, G., Kang, T., Jin, J.W. et al. Atomically sharp heteroepitaxial Hf2C edge contacts enabling barrier-free carrier injection in 2D HfSe2 semiconducting channels. Nat Commun (2026). https://doi.org/10.1038/s41467-026-70108-9
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DOI: https://doi.org/10.1038/s41467-026-70108-9
