Phonon-assisted exciton transport in an atomically thin semiconductor modulated by a remote electrostatic potential

The electrostatic moiré potential generated by twisted hexagonal boron nitride (t-hBN) has presented a novel platform for modulating adjacent functional layers. Here, we report the observation of distinct exciton transport behaviors in an atomically thin MoSe2 layer placed on a t-hBN substrate. The electrostatic potential imposed by the t-hBN substrate induces two exciton resonances in the MoSe2 layer, one of which is a Stark shift of the exciton resonance due to the in-plane electric field at the ferroelectric domain wall. We find the excitons within the domain and domain wall exhibit unique transport properties revealed by ultrafast transient reflection microscopy measurements. Our findings shed light on exciton dynamics governed by phonon interactions and highlight new strategies for controlling exciton diffusion, paving the way for advancements in future optoelectronic and photosynthetic devices.