Strain tuning of optical emission energy and polarization in monolayer and bilayer MoS2

By Chuanrang Zhu, Gang Wang, B. Liu, Xavier Marie, X. Qiao, X. Zhang, X. X. Wu, Heng Fan, P. Tan, T. Amand and 1 more. 2013

349 citations recorded by the source corpus.

We use micro-Raman and photoluminescence (PL) spectroscopy at 300 K to investigate the influence of uniaxial tensile strain on the vibrational and optoelectronic properties of monolayer and bilayer MoS2 on a flexible substrate. The initially degenerate E' monolayer Raman mode is split into a doublet as a direct consequence of the strain applied to MoS2 through Van der Waals coupling at the sample-substrate interface. We observe a strong shift of the direct band gap of 48 meV/(% of strain) for the monolayer and 46 meV/% for the bilayer, whose indirect gap shifts by 86 meV/%. We find a strong decrease of the PL polarization linked to optical valley initialization for both monolayer and bilayer samples, indicating that scattering to the spin-degenerate Gamma valley plays a key role.

Subfields: Electrical and Electronic Engineering, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/e1e2d39d7a991595ce84fb2f51c1fc8d4e3df297

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In Electrical and Electronic Engineering

1. T. Yu
2. Yujia Chen
3. Shengxue Yang
4. Qing Zhang
5. R. Ganatra
6. Chengbao Jiang

In Materials Chemistry

1. T. Yu
2. Chunxiao Cong
3. Yanlong Wang
4. Yujia Chen
5. Shengxue Yang
6. J. Shang
7. Qing Zhang
8. Junyong Kang

Citations in the corpus

• Strain engineering of two‐dimensional materials: Methods, properties, and applications (2021, background): “In aspect of optical properties, strain can directly change the phonon structure and energy band structure of 2D materials, resulting in the shift of Raman and photoluminescence (PL) peaks.(21,22) Especially, strain induces the transition from indirect to direct band gap in 2D materials, which great”
• Strain-induced direct–indirect bandgap transition and phonon modulation in monolayer WS2 (2015, background): “2%, there was an obvious redshift in the PL emission, while the line shape remained unchanged, which is similar to previous observations for strained monolayer MoS2 [22, 24].”