Exciton Emission in Monolayer Tungsten Disulfide under Synergistic Strain and Electric Field

Abstract

The substantial exciton binding energy in two-dimensional transition metal dichalcogenide (TMDC) monolayers offers a prime platform for investigating many-body effects and realizing excitonic devices at room temperature. In these monolayers, exciton behaviors can be efficiently modulated by external stimuli, such as temperature, mechanical stress, and electric fields. Particularly, in-plane electrical modulation of exciton emission and distribution has been achieved recently; however, the modulation depth is still too small to support practice application. Here, by combining in-plane electric field with a local strain, we have prominently elevated the modulation depth of exciton emission in monolayer tungsten disulfide (WS₂) by ∼3 times. Such modulation relies on both the electric field modulated exciton emission via trap states at the Au-WS₂ interface and the strain field-induced exciton funneling effect at the localized strained area. This work sheds light on the cooperative multifield control of excitonic devices based on monolayer TMDCs.