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With reduced dimensionality and a high surface area-to-volume ratio, two-dimensional (2D) semiconductors exhibit intriguing electronic properties that are exceptionally sensitive to surrounding environments, including directly interfacing gate dielectrics. These influences are tightly correlated to their inherent behavior, making it critical to examine when extrinsic charge carriers are intentionally introduced to the channel for complementary functionality. This study explores the physical origin of the competitive transition between intrinsic and extrinsic charge carrier conduction in extrinsically p-doped MoS2, highlighting the central role of interactions of the channel with amorphous gate dielectrics. By providing a pristine interface to the channel and controlling the degree of such interaction using hexagonal boron nitride (h-BN) spacers of different thicknesses, we determined three distinctive interaction modes: noncontact, proximity, and direct-contact. In the direct-contact mode without an h-BN spacer, charge transfer and orbital mixing induce ambipolar conduction in few-layer p-doped MoS2, showing an unexpected gate-dependent crossover between coexisting extrinsic and intrinsic conduction. Kelvin probe force microscopy and Raman spectroscopy confirm n-type doping in the channel through dielectric interactions, further supported by first-principles calculations identifying unpassivated silicon dangling bonds on the SiO2 surface as the origin of n-doping. On the contrary, depending on the thickness of the h-BN spacers, the noncontact mode maintains degenerate p-type conduction in the transfer curve, while the proximity mode enables gate-responsive p-type conduction, emphasizing the significant role of dielectric interactions in modulating charge transport. These findings underscore the importance of dielectric engineering in optimizing 2D semiconductor devices, particularly for improving the p-type transistor performance.

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• In Copyright
  

  This document is the Accepted Manuscript version of a Published Article that appeared in final form in ACS Nano, copyright © 2024 American Chemical Society. To access the final published article, see https://doi.org/10.1021/acsnano.4c15202.

Keyword: Two-dimensional (2D) semiconductor, Gate dielectric interaction, MoS2 transistor

Date published: 2025-01-14

Publisher: American Chemical Society (ACS)

Journal:

• ACS Nano (ISSN: 1936086X) vol. 19 issue. 1 p. 1630-1641

Funding:

• Ulsan National Institute of Science and Technology 1.240031
• National Research Foundation of Korea 2022M3H4A1A01013228
• National Research Foundation of Korea 2022M3I7A2079098
• National Research Foundation of Korea RS-2023-00258309
• National Research Foundation of Korea RS-2024-00336695
• Ministry of Education, Culture, Sports, Science and Technology 21H05233
• Ministry of Education, Culture, Sports, Science and Technology 23H02052
• National Natural Science Foundation of China 11991060
• National Natural Science Foundation of China 12088101
• National Natural Science Foundation of China 12393831
• Samsung 2.231170.01

Manuscript type: Author's version (Accepted manuscript)

MDR DOI:

First published URL: https://doi.org/10.1021/acsnano.4c15202

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Updated at: 2026-07-06 09:47:18 +0900

Published on MDR: 2026-07-06 12:30:02 +0900