# Monolayer indium selenide: an indirect bandgap material exhibits efficient brightening of dark excitons

https://mdr.nims.go.jp/datasets/f5328bc3-a232-49c5-bd3d-a6123b0a076e

## File

- [s41699-024-00450-3.pdf](https://mdr.nims.go.jp/filesets/96912837-769b-4368-8ed9-2850ee6d0cf4/download) ([Detail](https://mdr.nims.go.jp/filesets/96912837-769b-4368-8ed9-2850ee6d0cf4.md))

## Id

f5328bc3-a232-49c5-bd3d-a6123b0a076e

## Local identifier



## Visibility

open_to_public

## State

published

## Created at

2025-02-27T04:57:11.212497Z

## Updated at

2025-02-27T23:30:58.589681Z

## Published at

2025-02-27T23:30:58.670381Z

## Doi



## First published url

https://doi.org/10.1038/s41699-024-00450-3

## Date published

2024-02-20

## Recorded date published



## Resource type

journal_article

## Manuscript type

vor

## Collection



## Title

- title: 'Monolayer indium selenide: an indirect bandgap material exhibits efficient
    brightening of dark excitons'
  title_type: original
  lang: en

## Description

- description: Indium selenide (InSe) is a two-dimensional III-VI post-transition
    metal chalcogenide semiconductor with promising electronic and optoelectronic
    properties. The large layer-dependence of its band gap and its tightly bounded
    excitons make atomically thin InSe a unique material for achieving an appreciable
    bandwidth ranging from the whole visible region to the near-infrared region for
    various applications in optoelectronics. It is known that the direct-to-indirect
    band gap transition of atomically thin InSe leads to a weaker emission from the
    lowest-energy bright exciton (A exciton) as the layer number decreases. However,
    the A exciton emis-sion of monolayer (ML) InSe was observed to be either absent
    or very weak in recent experi-mental studies, rendering the nature of the lowest-energy
    excitonic states of ML InSe and its optical properties largely unknown. In this
    work, we systematically measure and analyze the photoluminescence of hexagonal
    boron nitride-encapsulated InSe from ML InSe to bulk InSe. Remarkably, ML InSe
    exhibits pronounced luminescence near the A exciton excitation energy despite
    its indirect band structure. We uncover the mechanism for brightening the momentum-indirect
    dark excitons of ML InSe, which can be attributed to the efficient acoustic phonon-assisted
    recombination facilitated by strong exciton-phonon coupling and the extended wave-function
    in momentum space. Moreover, the asymmetric line shape of the lowest-energy exci-tonic
    emission for atomically thin InSe can be well accounted for by a carrier localization
    model. Our work demonstrates the unique excitonic properties of atomically thin
    InSe, which can pro-vide potential avenues for manipulating the tightly bound
    dark excitons of two-dimensional ma-terial-based optoelectronic devices.
  description_type: abstract
  lang: und

## Creator

- name: Naomi Tabudlong Paylaga
  role: author
- name: Chang-Ti Chou
  role: author
- name: Chia-Chun Lin
  role: author
- name: Takashi Taniguchi
  role: author
  orcid: https://orcid.org/0000-0002-1467-3105
  organization: National Institute for Materials Science
  ror: https://ror.org/026v1ze26
- name: Kenji Watanabe
  role: author
  orcid: https://orcid.org/0000-0003-3701-8119
  organization: National Institute for Materials Science
  ror: https://ror.org/026v1ze26
- name: Raman Sankar
  role: author
- name: Yang-hao Chan
  role: author
- name: Shao-Yu Chen
  role: author
- name: Wei-Hua Wang
  role: author

## Contact agent



## Publisher

organization: Springer Science and Business Media LLC

## Managing organization



## Keyword

- subject: Atomically thin
  schema: not_defined
- subject: InSe
  schema: not_defined
- subject: dark excitons
  schema: not_defined

## Rights

- identifier: https://creativecommons.org/licenses/by/4.0/

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## Embargo



## Journal

- title: npj 2D Materials and Applications
  issn: '23977132'
  volume: '8'
  issue: '1'
  article_number: '12'

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## Fileset

- id: 96912837-769b-4368-8ed9-2850ee6d0cf4
  filename: s41699-024-00450-3.pdf
  content_type: application/pdf
  size: 1714246
  md5: 25c2109b6483108d26e8681b7bc73995

## Thumbnail

fileset_id: 96912837-769b-4368-8ed9-2850ee6d0cf4
filename: s41699-024-00450-3.pdf