Spatiotemporally Controlled Room Temperature Exciton Transport under Dynamic Pressure

TL;DR

This study demonstrates controlled, directional exciton transport in 2D TMDs at room temperature using surface acoustic waves, enabling precise steering and insights into exciton-strain interactions for potential optoelectronic applications.

Contribution

It introduces a method to steer exciton flux in 2D materials using dynamic strain from surface acoustic waves at room temperature, revealing weak coupling effects.

Findings

Maximum exciton drift velocity of 600 m/s

Controlled exciton steering via phase modulation

Insights into exciton-strain weak coupling regime

Abstract

Two-dimensional transition metal dichalcogenides (TMDs) provide an attractive platform for studying strain dependent exciton transport at room temperature due to large exciton binding energy and strong bandgap sensitivity to mechanical stimuli. Here, we use Rayleigh type surface acoustic wave (SAW) to demonstrate controlled and directional exciton transport under weak coupling regime at room temperature. We screen the in-plane piezoelectric field using photogenerated carriers to study transport under type-I bandgap modulation and measure a maximum exciton drift velocity of 600 m/s. Furthermore, we demonstrate precise steering of exciton flux by controlling the relative phase between the input RF excitation and exciton photogeneration. The results provide important insight into the weak coupling regime between dynamic strain wave and room temperature excitons in a 2D semiconductor system and pave way to exciting applications of excitonic devices in data communication and processing, sensing and energy conversion.