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Monolayer MoS2-based transistors with low contact resistance by inserting ultrathin Al2O3 interfacial layer

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Abstract

Transition metal dichalcogenides (TMDCs) are promising high performance electronic materials due to their interesting semiconductor properties. However, it is acknowledged that the effective electrical contact between TMDCs-layered materials and metals remains one of the major challenges. In this work, the homogeneous monolayer MoS2 films with high crystalline quality were prepared by chemical vapor deposition method on SiO2/Si substrates. The back-gate field-effect transistors (FETs) were fabricated by inserting an ultrathin Al2O3 interlayer between the metal electrodes and MoS2 nanosheets. With the addition of an ultrathin 0.8 nm Al2O3 interlayer, the contact resistance decreased dramatically from 59.9 to 1.3 kΩ μm and the Schottky barrier height (SBH) dropped from 102 to 27 meV compared with devices without the Al2O3 interlayer. At the same time, the switching ratio increased from ∼106 to ∼108, and both the on-current and field-effect mobility were greatly improved. We find that the ultrathin Al2O3 interlayer can not only reduce the SBH to alleviate the Fermi level pinning phenomenon at the interface, but also protect the channel materials from the influence of air and moisture as a covering layer. In addition, the lattice and band structures of Al2O3/MoS2 film were calculated and analyzed by first-principles calculation. It is found that the total density of states of the Al2O3/MoS2 film exhibits interfacial polarized metals property, which proves the higher carrier transport characteristics. FETs with Al2O3 interlayers have excellent stability and repeatability, which can provide effective references for future low power and high performance electronic devices.

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Author notes

  1. These authors contributed equally to this work.

Authors and Affiliations

  1. Tianjin Key Laboratory of Film Electronic & Communication Devices, School of Integrated Circuit Science and Engineering, Tianjin University of Technology, Tianjin, 300384, China

    Gang Chen, Xin Lin, Fang Wang, Kai Hu, Xin Shan, ZeYu Wu, YuPeng Zhang, WeiCan Nie, JiXiang Zhong & KaiLiang Zhang

  2. School of Materials Science and Engineering, Tianjin University of Technology, Tianjin, 300384, China

    Xin Lin

  3. Tianjin Key Laboratory of Composite and Functional Materials, Key Laboratory of Advanced Ceramics and Machining Technology (Ministry of Education), School of Materials Science and Engineering, Tianjin University, Tianjin, 300072, China

    Yuan Liu

  4. School of Integrated Circuits, Beijing National Research Center for Information Science and Technology (BNRist), Tsinghua University, Beijing, 100084, China

    TianLing Ren

Authors
  1. Gang Chen
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  2. Xin Lin
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  3. Yuan Liu
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  4. Fang Wang
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  11. TianLing Ren
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Corresponding authors

Correspondence to Fang Wang or KaiLiang Zhang.

Additional information

This work was supported by the National Key Research and Development Program of China (Grant No. 2017YFB0405600), the Natural Science Foundation of Tianjin City (Grant Nos. 18JCYBJC85700 and 18JCZDJC30500), the National Natural Science Foundation of China (Grant Nos. 62001326, 61274113, and 61404091), the Open Project of State Key Laboratory of Functional Materials for Information (Grant No. SKL202007), and the Science and Technology Planning Project of Tianjin City (Grant No. 20ZYQCGX00070).

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Chen, G., Lin, X., Liu, Y. et al. Monolayer MoS2-based transistors with low contact resistance by inserting ultrathin Al2O3 interfacial layer. Sci. China Technol. Sci. 66, 1831–1840 (2023). https://doi.org/10.1007/s11431-022-2330-3

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  • DOI: https://doi.org/10.1007/s11431-022-2330-3

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