# Interlayer exciton dynamics in a dichalcogenide monolayer heterostructure

## TL;DR

This study investigates interlayer excitons in MoSe2/WSe2 heterostructures, revealing complex temperature and power-dependent behaviors explained by exciton diffusion and interactions, advancing understanding of excitonic phenomena in 2D materials.

## Contribution

It provides new insights into the temperature and power dependence of interlayer excitons in transition-metal dichalcogenide heterostructures, highlighting the roles of diffusion and exciton interactions.

## Key findings

- Unusual redshift of interlayer exciton with temperature
- Pronounced blueshift of emission with increasing excitation power
- Interlayer exciton behavior explained by diffusion and dipolar interactions

## Abstract

In heterostructures consisting of different transition-metal dichalcogenide monolayers, a staggered band alignment can occur, leading to rapid charge separation of optically generated electron-hole pairs into opposite monolayers. These spatially separated electron-hole pairs are Coulomb-coupled and form interlayer excitons. Here, we study these interlayer excitons in a heterostructure consisting of MoSe$_2$ and WSe$_2$ monolayers using photoluminescence spectroscopy. We observe a non-trivial temperature dependence of the linewidth and the peak energy of the interlayer exciton, including an unusually strong initial redshift of the transition with temperature, as well as a pronounced blueshift of the emission energy with increasing excitation power. By combining these observations with time-resolved photoluminescence measurements, we are able to explain the observed behavior as a combination of interlayer exciton diffusion and dipolar, repulsive exciton-exciton interaction.