Article Patternable laser-oxidized Ta2O5 dielectric and TaS2 contact for optimizing subthreshold swing of MoS2 field-effect transistors

Kuan-Cheng Lu ; Pen-Yuan Shih ; Pin-Hsien Lin ; Shih-Hao Wu ; Kimitoshi Kono ; Wen-Bin Jian ORCID ; Yu-Han Lin ; Yo-Yao Ho ; Ching-Hwa Ho ORCID ; Shin-Yuan Wang ; Chao-Hsin Chien ; Ching-Yu Chiang ORCID ; Shu-Jui Chang ; Yu-Che Huang ; Kenji Watanabe SAMURAI ORCID ; Takashi Taniguchi SAMURAI ORCID ; Kazuhito Tsukagoshi SAMURAI ORCID ; Chenming Hu ORCID

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Kuan-Cheng Lu, Pen-Yuan Shih, Pin-Hsien Lin, Shih-Hao Wu, Kimitoshi Kono, Wen-Bin Jian, Yu-Han Lin, Yo-Yao Ho, Ching-Hwa Ho, Shin-Yuan Wang, Chao-Hsin Chien, Ching-Yu Chiang, Shu-Jui Chang, Yu-Che Huang, Kenji Watanabe, Takashi Taniguchi, Kazuhito Tsukagoshi, Chenming Hu. Patternable laser-oxidized Ta2O5 dielectric and TaS2 contact for optimizing subthreshold swing of MoS2 field-effect transistors. Applied Surface Science Advances. 2026, 32 (), 100955. https://doi.org/10.1016/j.apsadv.2026.100955

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(abstract)

Recent progress has achieved a high on-current density and a low contact resistivity for n-type field-effect transistors using two-dimensional (2D) semiconductors such as MoS2 and WSe2. However, there remain other issues of device parameters, such as complementary transistors with a single 2D semiconductor, environmental package, and dielectric layers. In particular, the integration of an optimum dielectric and ideal interfacial contact for mass production shall play an important role in future electronics designs. Here, we demonstrate patternable laser oxidation to convert TaS2 into Ta2O5 as an ultra-flat dielectric layer, as evidenced by energy-dispersive X-ray spectroscopy, nano-X-ray absorption near edge structure, and atomic force microscopy. With this patternable conversion, we also demonstrate the implementation of TaS2 as contact electrodes on MoS2 channels. The Ta2O5 layer reveals a dielectric constant of 15.98 and a breakdown field of 5.5 MV/cm. A high on-current density of ~34.7 is attainable in Bi-contacted devices at a channel length of 1.0 μm. Moreover, the TaS2-contacted MoS2 transistors on Ta2O5 present an extremely low subthreshold swing of 59.8 mV/dec and a minimal hysteresis of 0.15 V. This indicates the superior feature of the Ta2O5 dielectric through patternable laser oxidation while keeping an ultra-flat interfacial surface.

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Keyword: Ta2O5, TaS2, subthreshold swing, MoS2, field-effect transistors

Date published: 2026-02-24

Publisher: Elsevier BV

Journal:

  • Applied Surface Science Advances (ISSN: 26665239) vol. 32 100955

Funding:

  • Japan Science and Technology Agency
  • Ministry of Education, Culture, Sports, Science and Technology
  • National Science and Technology Council NSTC-114-2112-M-A49-008
  • National Science and Technology Council NSTC 114-2634-F-A49-001
  • Core Research for Evolutional Science and Technology JPMJCR24A5
  • Japan Society for the Promotion of Science 21H05233
  • Japan Society for the Promotion of Science 23H02052

Manuscript type: Publisher's version (Version of record)

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First published URL: https://doi.org/10.1016/j.apsadv.2026.100955

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Updated at: 2026-03-04 16:30:07 +0900

Published on MDR: 2026-03-04 12:42:22 +0900

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