BROWSE

Related Scientist

cinap's photo.

cinap
나노구조물리연구단
more info

ITEM VIEW & DOWNLOAD

Impeding Exciton-Exciton Annihilation in Monolayer WS2 by Laser Irradiation

Cited 7 time in webofscience Cited 22 time in scopus
794 Viewed 253 Downloaded
Title
Impeding Exciton-Exciton Annihilation in Monolayer WS2 by Laser Irradiation
Author(s)
Yongjun Lee; Ganesh Ghimire; Shrawan Roy; Youngbum Kim; Changwon Seo; A. K. Sood; Joon I. Jang; Jeongyong Kim
Subject
transition metal dichalcogenides, ; EEA, ; photoluminescence, ; time-resolved photoluminescence, ; sulfur vacancy
Publication Date
2018-07
Journal
ACS PHOTONICS, v.5, no.7, pp.2904 - 2911
Publisher
AMER CHEMICAL SOC
Abstract
Monolayer (1L) transition metal dichalcogenides (TMDs) are two-dimensional direct-bandgap semiconductors with promising applications of quantum light emitters. Recent studies have shown that intrinsically low quantum yields (QYs) of 1L-TMDs can be greatly improved by chemical treatments. However, nonradiative excitonexciton annihilation (EEA) appears to significantly limit light emission of 1L-TMDs at a nominal density of photoexcited excitons due to strong Coulomb interaction. Here we show that the EEA rate constant (gamma) can be reduced by laser irradiation treatment in mechanically exfoliated monolayer tungsten disulfide (1L-WS2), causing significantly improved light emission at the saturating optical pumping level. Time-resolved photoluminescence (PL) measurements showed that ? reduced from 0.66 +/- 0.15 cm(2)/s to 0.20 +/- 0.05 cm(2)/s simply using our laser irradiation. The laser-irradiated region exhibited lower PL response at low excitation levels, however at the high excitation level displayed 3x higher PL intensity and QY than the region without laser treatment. The shorter PL lifetime and lower PL response at low excitation levels suggested that laser irradiation increased the density of sulfur vacancies of 1L-WS2, but we attribute these induced defects, adsorbed by oxygen in air, to the origin for reduced EEA by hindering exciton diffusion. Our laser irradiation was likewise effective for reducing EEA and increasing PL of chemically treated 1L-WS2 with a high QY, exhibiting the general applicability of our method. Our results suggest that excitonexciton interaction in 1L-TMDs may be conveniently controlled by the laser treatment, which may lead to unsaturated exciton emission at high excitation levels
URI
https://pr.ibs.re.kr/handle/8788114/5552
DOI
10.1021/acsphotonics.8b00249
ISSN
2330-4022
Appears in Collections:
Center for Integrated Nanostructure Physics(나노구조물리 연구단) > 1. Journal Papers (저널논문)
Files in This Item:
11-Impeding Exciton-Exciton Annihilation in Monolayer WS2 by Laser Irradiation.pdfDownload

qrcode

  • facebook

    twitter

  • Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.
해당 아이템을 이메일로 공유하기 원하시면 인증을 거치시기 바랍니다.

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.

Browse