Strain tuning of optical emission energy and polarization in monolayer and bilayer MoS 2
2013; American Physical Society; Volume: 88; Issue: 12 Linguagem: Inglês
10.1103/physrevb.88.121301
ISSN1550-235X
AutoresC. R. Zhu, Gang Wang, Baoli Liu, X. Marie, Xiaofen Qiao, Xin Zhang, Xianxin Wu, Heng Fan, Ping‐Heng Tan, T. Amand, B. Urbaszek,
Tópico(s)Perovskite Materials and Applications
ResumoWe use micro-Raman and photoluminescence (PL) spectroscopy at 300K 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^1_{2g} 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 48meV/(% of strain) for the monolayer and 46meV/% for the bilayer, whose indirect gap shifts by 86meV/%. 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.
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