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

2013/06/14 by G. Wang, C. R. Zhu, B. L. Liu +7 · 2 citations
Physics and Astronomy · #cond-mat.mes-hall #cond-mat.mtrl-sci

paper · pdf · doi:10.1103/physrevb.88.121301

published as Physical Review B 88, 121301(R) (2013) · 5 pages, 3 figures

arxiv created 2013/06/14 · arxiv updated 2013/09/11

Abstract

We 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 E¹_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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• Achieving Large Uniaxial and Homogeneous Strain in Two-Dimensional Materials
• Alloy engineering of excitonic properties in TMD monolayers

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