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A single-crystalline native dielectric for two-dimensional semiconductors with an equivalent oxide thickness below 0.5 nm


Scaling down the size of field-effect transistors in integrated circuits leads to higher speed, lower power consumption and increased integration density, but also results in short-channel effects. Transistors made using high-mobility two-dimensional (2D) semiconductor channels and ultrathin high-κ dielectrics can suppress this effect. However, it is difficult to integrate 2D semiconductors with dielectric layers that have an equivalent oxide thickness below 0.5 nm and low leakage current. Here we report the wafer-scale synthesis of β-Bi2SeO5—a single-crystalline native oxide with a dielectric constant of around 22—via the lithography-compatible ultraviolet-assisted intercalative oxidation of the high-mobility 2D semiconductor Bi2O2Se. We use the approach to create top-gated 2D transistors with sub-0.5-nm-equivalent-oxide-thickness dielectrics that exhibit leakage current below the low-power limit of 0.015 A cm−2 at a gate voltage of 1 V.

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Fig. 1: Intercalative oxidation of 2D Bi2O2Se for single-crystalline native oxide.
Fig. 2: UV-assisted controlled synthesis of 2D Bi2O2Se/β-Bi2SeO5 heterostructures.
Fig. 3: Dielectric properties of β-Bi2SeO5 single crystal.
Fig. 4: Sub-0.5-nm-EOT β-Bi2SeO5 dielectrics in 2D FETs.

Data availability

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


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We thank X. Wang and J. Pei for the kind help on the capacitance measurement of the metal–insulator–semiconductor heterostructure. We also thank D. Hu for his kind help in the contrast experiment of O3 oxidation with and without UV. We acknowledge Molecular Materials and Nanofabrication Laboratory (MMNL) in the College of Chemistry and Electron Microscopy Laboratory of Peking University for the use of instruments. We also acknowledge financial support from the National Natural Science Foundation of China (21733001, 21920102004, 11974023 and 52021006). H.P. acknowledges support from the Beijing National Laboratory for Molecular Sciences (BNLMS-CXTD-202001) and Tencent Foundation (The XPLORER PRIZE). P.G. acknowledges support from the Key Area R&D Program of Guangdong Province (2018B030327001 and 2018B010109009), and the ‘2011 Program’ from the Peking-Tsinghua-IOP Collaborative Innovation Center of Quantum Matter, Youth Innovation Promotion Association, CAS. J.Y. and K.L. were supported by Welch Foundation grant F-1814.

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Authors and Affiliations



Under the direction of H.P., Y.Z. developed the controlled synthesis of single-crystalline β-Bi2SeO5 with the help of T.T. and C.Z. and fabricated the FET devices with sub-0.5-nm-EOT dielectric with the help of M.W., C.T. and Y.W. The MIM measurements for the dielectric constant was carried out by J.Y. under the supervision of K.L. The cross-sectional STEM measurements were performed by R.Z. under the direction of P.G. The top-view TEM, SAED and EDS characterizations were carried out by X.G. and Y.Z. The Bi2O2Se samples were supplied by C.T., M.Y. and Y.Z. The XRD measurements were performed by X.Z. The electron diffraction measurements were finished by X.G. The manuscript was written by H.P. and Y.Z. with input from K.L. and the other authors. The revision of the manuscript is finished by H.L., Y.Z. and H.P. All the work was supervised by H.P. All the authors contributed to the scientific planning and discussions.

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Correspondence to Hailin Peng.

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Nature Electronics thanks Tianyou Zhai and Zhixian Zhou for their contribution to the peer review of this work.

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Zhang, Y., Yu, J., Zhu, R. et al. A single-crystalline native dielectric for two-dimensional semiconductors with an equivalent oxide thickness below 0.5 nm. Nat Electron 5, 643–649 (2022).

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