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Opposite behavior of ultrafast dynamics of exciton shift and linewidth broadening in bilayer ReS2

Title
Opposite behavior of ultrafast dynamics of exciton shift and linewidth broadening in bilayer ReS2
Author
심상완
Issue Date
2021-01
Publisher
AMER PHYSICAL SOC
Citation
PHYSICAL REVIEW B, v. 103, NO 1, Article no. 014309, 8pp
Abstract
The optical and optoelectronic properties of two-dimensional (2D) semiconductors are dominated by excitons, which usually appear as well-defined peaks in the spectral domain. Thus, detailed behaviors of excitons can be understood by tracking transient changes of the fundamental spectral observables, i.e., the resonance energy and the spectral linewidth. Rhenium disulfide (ReS2) is a 2D semiconductor that has recently attracted attention due to its excellent exciton properties, such as light-polarization selectivity and anisotropic coherent effects. However, an understanding of exciton dynamics and spectral behavior of excitons in ReS2 is lacking. Here, we used time- and spectrally resolved pump-probe spectroscopy to investigate ultrafast exciton dynamics in bilayer ReS2. Upon photoexcitation, the exciton resonance undergoes linewidth broadening and redshift, but they exhibit different dynamics, and an opposite pump fluence dependence on the approximately hundreds of picoseconds timescale. This is because the spectral broadening and the red-shift both have different origins (the exciton-carrier scattering and exciton-exciton attractive interaction, respectively) and different decay mechanisms (the trapping of carriers and exciton-exciton annihilation, respectively). On a longer timescale of similar to 100 ps, both the spectral broadening and the redshift are well explained by the indirect recombination of carriers and lattice heating. This work provides in-depth insight into exciton dynamics in 2D rhenium dichalcogenides.
URI
https://journals.aps.org/prb/abstract/10.1103/PhysRevB.103.014309https://repository.hanyang.ac.kr/handle/20.500.11754/167029
ISSN
2469-9950; 2469-9969
DOI
10.1103/PhysRevB.103.014309
Appears in Collections:
COLLEGE OF ENGINEERING SCIENCES[E](공학대학) > ELECTRICAL ENGINEERING(전자공학부) > Articles
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