Raman-scattering measurements and first-principles calculations of strain-induced phonon shifts in monolayer MoS${}_{2}$

Rapid Communication

Raman-scattering measurements and first-principles calculations of strain-induced phonon shifts in monolayer MoS $_{2}$

C. Rice, R. J. Young, R. Zan, U. Bangert, D. Wolverson, T. Georgiou, R. Jalil, and K. S. Novoselov

Phys. Rev. B 87, 081307(R) – Published 15 February 2013

Abstract

The effect of strain on the phonon modes of monolayer and few-layer MoS $_{2}$ has been investigated by observing the strain-induced shifts of the Raman-active modes. Uniaxial strain was applied to a sample of thin-layer MoS $_{2}$ sandwiched between two layers of optically transparent polymer. The resulting band shifts of the $E_{2 g}^{1}$ ( $\sim$ $385.3 {cm}^{- 1}$ ) and $A_{1 g}$ ( $\sim$ $402.4 {cm}^{- 1}$ ) Raman modes were found to be small but observable. First-principles plane-wave calculations based on density functional perturbation theory were used to determine the Grüneisen parameters for the $E_{1 g}$ , $E_{2 g}^{1}$ , $A_{1 g}$ , and $A_{2 u}$ modes and predict the experimentally observed band shifts for the monolayer material. The polymer–MoS $_{2}$ interface is found to remain intact through several strain cycles. As an emerging 2D material with potential in future nanoelectronics, these results have important consequences for the incorporation of thin-layer MoS $_{2}$ into devices.