Control of trion-to-exciton conversion in monolayer WS2 by orbital angular momentum of light

Rahul Kesarwani, Kristan Bryan Simbulan, Teng De Huang, Yu Fan Chiang, Nai Chang Yeh*, Yann Wen Lan, Ting Hua Lu

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Controlling the density of exciton and trion quasiparticles in monolayer two-dimensional (2D) materials at room temperature by nondestructive techniques is highly desired for the development of future optoelectronic devices. Here, the effects of different orbital angular momentum (OAM) lights on monolayer tungsten disulfide at both room temperature and low temperatures are investigated, which reveal simultaneously enhanced exciton intensity and suppressed trion intensity in the photoluminescence spectra with increasing topological charge of the OAM light. In addition, the trion-to-exciton conversion efficiency is found to increase rapidly with the OAM light at low laser power and decrease with increasing power. Moreover, the trion binding energy and the concentration of unbound electrons are estimated, which shed light on how these quantities depend on OAM. A phenomenological model is proposed to account for the experimental data. These findings pave a way toward manipulating the exciton emission in 2D materials with OAM light for optoelectronic applications.

Original languageEnglish
Article number0100
JournalScience Advances
Volume8
Issue number13
DOIs
Publication statusPublished - 2022 Apr

ASJC Scopus subject areas

  • General

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