Abstract

High-mobility semiconducting ultrathin films form the basis of modern electronics, and may lead to the scalable fabrication of highly performing devices. Because the ultrathin limit cannot be reached for traditional semiconductors, identifying new two-dimensional materials with both high carrier mobility and a large electronic bandgap is a pivotal goal of fundamental research1,2,3,4,5,6,7,8,9. However, air-stable ultrathin semiconducting materials with superior performances remain elusive at present10. Here, we report ultrathin films of non-encapsulated layered Bi2O2Se, grown by chemical vapour deposition, which demonstrate excellent air stability and high-mobility semiconducting behaviour. We observe bandgap values of 0.8 eV, which are strongly dependent on the film thickness due to quantum-confinement effects. An ultrahigh Hall mobility value of >20,000 cm2 V−1 s−1 is measured in as-grown Bi2O2Se nanoflakes at low temperatures. This value is comparable to what is observed in graphene grown by chemical vapour deposition11 and at the LaAlO3–SrTiO3 interface12, making the detection of Shubnikov–de Haas quantum oscillations possible. Top-gated field-effect transistors based on Bi2O2Se crystals down to the bilayer limit exhibit high Hall mobility values (up to 450 cm2 V−1 s−1), large current on/off ratios (>106) and near-ideal subthreshold swing values (65 mV dec–1) at room temperature. Our results make Bi2O2Se a promising candidate for future high-speed and low-power electronic applications.

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Acknowledgements

The authors thank X. B. Ren and C. H. Jin for analysis of elemental maps. H.L.P. acknowledges support from the National Basic Research Program of China (grant numbers 2014CB932500 and 2016YFA0200101), the National Natural Science Foundation of China (grant number 21525310) and the National Program for Support of Top-Notch Young Professionals. H.T.Y., Y.C. and H.Y.H. were supported by the Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering, under contract number DE-AC02-76SF00515.

Author information

Author notes

    • Jinxiong Wu
    •  & Hongtao Yuan

    These authors contributed equally to this work.

Affiliations

  1. Center for Nanochemistry, Beijing National Laboratory for Molecular Sciences (BNLMS), College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China

    • Jinxiong Wu
    • , Wenhui Dang
    • , Congwei Tan
    • , Yujing Liu
    • , Jianbo Yin
    • , Yubing Zhou
    • , Zhongfan Liu
    •  & Hailin Peng
  2. National Laboratory of Solid-State Microstructures, College of Engineering and Applied Sciences, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China

    • Hongtao Yuan
  3. Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, USA

    • Hongtao Yuan
    • , Zhuoyu Chen
    • , Yi Cui
    •  & Harold Y. Hwang
  4. Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA

    • Hongtao Yuan
    • , Yi Cui
    •  & Harold Y. Hwang
  5. Key Laboratory for the Physics and Chemistry of Nanodevices, Department of Electronics, Peking University, Beijing 100871, China

    • Mengmeng Meng
    • , Shaoyun Huang
    •  & H. Q. Xu
  6. Department of Physics and Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, UK

    • Cheng Chen
    •  & Yulin Chen
  7. Max Planck Institute for Chemical Physics of Solids, D-01187 Dresden, Germany

    • Yan Sun
    •  & Binghai Yan
  8. School of Physical Science and Technology, ShanghaiTech University, Shanghai 200031, China

    • Yan Sun
    •  & Binghai Yan

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Contributions

H.P., J.W. and H.T.Y. conceived the original idea for the project. J.W. carried out the synthesis and structural characterizations of the bulk and two-dimensional crystals. The devices were fabricated by J.W. with M.M.'s help. H.T.Y., J.W., M.M., J.Y. and Z.C. performed the transport measurements and data analysis. Y.S. and Y.B. carried out the theoretical calculations. The ARPES measurements were done by C.C. and Y.L.C. The manuscript was written by H.P., H.T.Y. and J.W., with input from the other authors. All work was supervised by H.P. All authors contributed to the scientific planning and discussions.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Hailin Peng.

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DOI

https://doi.org/10.1038/nnano.2017.43

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