Effect of strain on exciton dynamics in monolayer WS2*

Abstract

The exciton dynamics in a WS2 monolayer with strain are studied by transient absorption measurements. We measure the differential transmission signal from monolayer WS2 as a function of the probe wavelength at different levels of strain applied to the sample. The differential transmission spectrum has a positive maximum value at about 614 nm and shows no significant strain dependence. By time-resolving the differential transmission signal, we find that the strain has a minimal effect on the exciton formation process. However, the exciton lifetime is significantly reduced by strain. These results provide useful information for applications of WS2 in flexible electronic and optoelectronic devices where strain is inevitable.