Issue 6, 2020

Lineshape characterization of excitons in monolayer WS2 by two-dimensional electronic spectroscopy

Abstract

The optical properties of monolayer transition metal dichalcogenides (TMDCs), an important family of two-dimensional (2D) semiconductors for optoelectronic applications, are dominated by two excitons A (XA) and B (XB) located at K/K's valleys. The lineshape of the excitons is an indicator of the interaction of the excitons with other particles and also largely determines the performance of TMDC-based optoelectronic devices. In this work, we apply 2D electronic spectroscopy (2DES), which enables separation of the intrinsic homogeneous linewidth and the extrinsic inhomogeneous linewidth, to dissect the lineshape of XA in monolayer WS2. With a home-built broadband optical parametric amplifier, the 2D spectra give the exciton linewidth values for extensive ranges of excitation densities and temperatures, reflecting inter-exciton and exciton–phonon interactions. Meanwhile, the time-domain evolution of the lineshape reveals a similar rate of spectral diffusion to that in quantum wells (QWs) based on III–V semiconductors.

Graphical abstract: Lineshape characterization of excitons in monolayer WS2 by two-dimensional electronic spectroscopy

Article information

Article type
Paper
Submitted
17 Mar 2020
Accepted
20 Apr 2020
First published
21 Apr 2020
This article is Open Access
Creative Commons BY license

Nanoscale Adv., 2020,2, 2333-2338

Lineshape characterization of excitons in monolayer WS2 by two-dimensional electronic spectroscopy

L. Guo, C. Chen, Z. Zhang, D. M. Monahan, Y. Lee and G. R. Fleming, Nanoscale Adv., 2020, 2, 2333 DOI: 10.1039/D0NA00240B

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