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 MoSe2 and WSe2 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.
@article{arxiv.1703.00379,
title = {Interlayer exciton dynamics in a dichalcogenide monolayer heterostructure},
author = {Philipp Nagler and Gerd Plechinger and Mariana V. Ballottin and Anatolie Mitioglu and Sebastian Meier and Nicola Paradiso and Christoph Strunk and Alexey Chernikov and Peter C. M. Christianen and Christian Schüller and Tobias Korn},
journal= {arXiv preprint arXiv:1703.00379},
year = {2017}
}