Biaxial versus uniaxial strain tuning of single-layer MoS${}_2$

Abstract

Strain engineering has arisen as a powerful technique to tune the electronic and optical properties of two-dimensional semiconductors like molybdenum disulfide (MoS2). Although several theoretical works predicted that biaxial strain would be more effective than uniaxial strain to tune the band structure of MoS2, a direct experimental verification is still missing in the literature. Here we implemented a simple experimental setup that allows to apply biaxial strain through the bending of a cruciform polymer substrate. We used the setup to study the effect of biaxial strain on the differential reflectance spectra of 12 single-layer MoS2 flakes finding a redshift of the excitonic features at a rate between -40 meV/% and -110 meV/% of biaxial tension. We also directly compare the effect of biaxial and uniaxial strain on the same single-layer MoS2 finding that the biaxial strain gauge factor is 2.3 times larger than the uniaxial strain one.

5 figures + 1 table in the main text. 6 figures in the supp. info

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Cited by in corpus (6)

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• Strain-induced superfluid transition for atoms on graphene
• Tunable biaxial strain device for low dimensional materials
• Mechanical Detuning of Exciton-Phonon Resonance in WS2
• Measurements of absolute bandgap deformation-potentials of optically-bright bilayer WSe${}_2$