# Understanding the interplay of defects, oxygen, and strain in 2D materials for next-generation optoelectronics

https://mdr.nims.go.jp/datasets/9ba46d99-8fa3-4437-b9e4-fd4edc8cc79f

## File

- [2024A00771G_accepted_manuscript.pdf](https://mdr.nims.go.jp/filesets/d1ea4aec-b17d-43b8-a0e1-b9a389cc798b/download) ([Detail](https://mdr.nims.go.jp/filesets/d1ea4aec-b17d-43b8-a0e1-b9a389cc798b.md))

## Id

9ba46d99-8fa3-4437-b9e4-fd4edc8cc79f

## Local identifier



## Visibility

open_to_public

## State

published

## Created at

2025-08-29T02:50:44.937254Z

## Updated at

2025-08-29T23:30:17.111527Z

## Published at

2025-08-29T23:17:29.192850Z

## Doi



## First published url

https://doi.org/10.1088/2053-1583/ad4e44

## Date published

2024-10-01

## Recorded date published

2024-10-1

## Resource type

journal_article

## Manuscript type

accepted_manuscript

## Collection



## Title

- title: Understanding the interplay of defects, oxygen, and strain in 2D materials
    for next-generation optoelectronics
  title_type: original
  lang: en

## Description

- description: 2D transition metal dichalcogenides (TMDs) are leading materials for
    next-generation optoelectronics, but fundamental problems stand enroute to commercialization.
    These problems include firstly, the widely debated defect and strain-induced origins
    of intense low-energy broad luminescence peaks (L-peak) observed at low temperatures.
    Secondly, role of oxygen in tuning properties via chemisorption and physisorption
    is intriguing but challenging to understand. Thirdly, physical understanding of
    benefits of hBN encapsulation is inadequate. Using a series of samples, we decouple
    contributions of oxygen, defects, adsorbates, and strain on optical properties
    of monolayer MoS<sub>2</sub>. Defect-origin of L-peak is confirmed by temperature
    and power-dependent photoluminescence (PL) measurements, with a dramatic redshift
    ~ 130 meV for oxygen-assisted chemical vapour deposition (O-CVD) samples (c.f.
    exfoliated). Anomalously, O-CVD samples show high A-exciton PL at room temperature
    (c.f. exfoliated), but reduced PL at low temperatures, attributed to strain-induced
    direct-to-indirect bandgap-crossover in low-defect O-CVD MoS<sub>2</sub>. These
    observations are consistent with our density functional theory calculations, and
    supported by Raman spectroscopy. In exfoliated samples, charged O-adatoms are
    identified as thermodynamically favourable defects, and create in-gap states.
    Beneficial effect of encapsulation originates from reduction of charged O-adatoms
    and adsorbates. This experimental-theoretical study uncovers the type of defects
    in each sample, enables an understanding of the combined effect of defects, strain
    and oxygen on band structure, and enriches understanding of effects of encapsulation.
    This work proposes O-CVD for creating high-quality materials for optoelectronics.
  description_type: abstract
  lang: en

## Creator

- name: Keerthana S Kumar
  role: author
- name: Ajit Kumar Dash
  role: author
- name: Hasna Sabreen H
  role: author
- name: Manvi Verma
  role: author
- name: Vivek Kumar
  role: author
- name: Kenji Watanabe
  role: author
  orcid: https://orcid.org/0000-0003-3701-8119
  organization: National Institute for Materials Science
- name: Takashi Taniguchi
  role: author
  orcid: https://orcid.org/0000-0002-1467-3105
  organization: National Institute for Materials Science
- name: Gopalakrishnan Sai Gautam
  role: author
- name: Akshay Singh
  role: author

## Contact agent



## Publisher

organization: IOP Publishing

## Managing organization



## Keyword

- subject: MoS2
  schema: not_defined
- subject: strain
  schema: not_defined
- subject: defects
  schema: not_defined
- subject: 2D materials
  schema: not_defined
- subject: optical spectroscopy
  schema: not_defined
- subject: DFT
  schema: not_defined
- subject: oxygen
  schema: not_defined

## Rights

- identifier: https://creativecommons.org/licenses/by-nc-nd/3.0/

## Other identifier(s)



## Data origin

- data_origin_type: other

## Embargo

start_date: 2024-07-08
end_date: 2025-07-08

## Journal

- title: 2D Materials
  issn: '20531583'
  volume: '11'
  issue: '4'
  start_page: 45003
  end_page: 45003
  article_number: '045003'

## Conference



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## Funding

- funder_name: Prime Ministers Research Fellowship
- funder_name: INSPIRE-DST
- identifier: SRG-2020-000133
  funder_name: Science and Engineering Research Board
- funder_name: Department of Science and Technology India
- funder_name: Ministry of Electronics and Information technology
- funder_name: National Supercomputing Mission
- identifier: 19H05790
  funder_name: Japan Society for the Promotion of Science

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## Fileset

- id: d1ea4aec-b17d-43b8-a0e1-b9a389cc798b
  filename: 2024A00771G_accepted_manuscript.pdf
  content_type: application/pdf
  size: 4766140
  md5: d38f744e3ee5ce25ffb60d01e7d0a4b5

## Thumbnail

fileset_id: d1ea4aec-b17d-43b8-a0e1-b9a389cc798b
filename: 2024A00771G_accepted_manuscript.pdf