Article Defect Passivation of 2D Semiconductors by Fixating Chemisorbed Oxygen Molecules via h‐BN Encapsulations

Jin‐Woo Jung ; Hyeon‐Seo Choi ; Young‐Jun Lee ; Youngjae Kim ; Takashi Taniguchi SAMURAI ORCID (National Institute for Materials ScienceROR) ; Kenji Watanabe SAMURAI ORCID (National Institute for Materials ScienceROR) ; Min‐Yeong Choi ; Jae Hyuck Jang ; Hee‐Suk Chung ; Dohun Kim ; Youngwook Kim ; Chang‐Hee Cho

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Jin‐Woo Jung, Hyeon‐Seo Choi, Young‐Jun Lee, Youngjae Kim, Takashi Taniguchi, Kenji Watanabe, Min‐Yeong Choi, Jae Hyuck Jang, Hee‐Suk Chung, Dohun Kim, Youngwook Kim, Chang‐Hee Cho. Defect Passivation of 2D Semiconductors by Fixating Chemisorbed Oxygen Molecules via h‐BN Encapsulations. Advanced Science. 2024, 11 (22), 2310197.
SAMURAI

Description:

(abstract)

Monolayer transition metal dichalcogenides (TMDs) have received great attention due to their fascinating physical properties and their potential for applications in novel semiconductor devices. However, the intrinsic physical properties of TMDs can be significantly altered by extrinsic disorders such as surface roughness and charge disorder induced by substrates. The encapsulation of TMDs using hexagonal boron nitride layers has been proposed as a practical way to reduce substrate-induced disorders. Despite experimental advances, the exact role of hexagonal boron nitride encapsulation remains unclear in terms of defect physics in TMDs. Here, we found that h-BN encapsulation effectively passivates the defects of monolayer WS2 by anchoring the adsorbed oxygen atoms onto monolayer WS2 crystals. Due to defect passivation by h-BN encapsulation, the excess electron density in monolayer WS2 crystals is greatly lowered and stabilized, resulting in two orders of magnitude lower exciton annihilation by trion conversion and Auger recombination processes. Furthermore, the valley polarization becomes robust against the various excitation and ambient conditions in the h-BN encapsulated WS2 crystals. Our findings provide insight into the role of h-BN encapsulation and the related excitonic properties of 2D semiconductors.

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Keyword: Hexagonal boron nitride, defect-related gap states, WS2 crystals

Date published: 2024-03-17

Publisher: Wiley

Journal:

  • Advanced Science (ISSN: 21983844) vol. 11 issue. 22 2310197

Funding:

  • National Research Foundation of Korea 2019R1A2C1088525
  • National Research Foundation of Korea RS‐2023‐00236798
  • National Research Foundation of Korea 2020R1C1C1006914
  • Japan Society for the Promotion of Science 19H05790
  • Japan Society for the Promotion of Science 20H00354
  • Japan Society for the Promotion of Science 21H05233
  • Ministry of Trade, Industry and Energy 20010542

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

MDR DOI:

First published URL: https://doi.org/10.1002/advs.202310197

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Updated at: 2025-02-14 12:32:08 +0900

Published on MDR: 2025-02-14 12:32:08 +0900