Atomically thin semiconductors made from transition metal dichalcogenides (TMDs) are model systems for investigations of strong light-matter interactions and applications in nanophotonics, opto-electronics and valley-tronics. However, the photoluminescence spectra of TMD monolayers display a large number of features that are particularly challenging to decipher. On a practical level, monochromatic TMD-based emitters would be beneficial for low-dimensional devices but this challenge is yet to be resolved. Here, we show that graphene, directly stacked onto TMD monolayers enables single and narrow-line photoluminescence arising solely from TMD neutral excitons. This filtering effect stems from complete neutralization of the TMD by graphene combined with selective non-radiative transfer of long-lived excitonic species to graphene. Our approach is applied to four tungsten and molybdenum-based TMDs and establishes TMD/graphene heterostructures as a unique set of opto-electronic building blocks, suitable for electroluminescent systems emitting visible and near-infrared photons at near THz rate with linewidths approaching the lifetime limit.
@article{arxiv.1908.10690,
title = {Filtering the photoluminescence spectra of atomically thin semiconductors with graphene},
author = {Etienne Lorchat and Luis E. Parra López and Cédric Robert and Delphine Lagarde and Guillaume Froehlicher and Takashi Taniguchi and Kenji Watanabe and Xavier Marie and Stéphane Berciaud},
journal= {arXiv preprint arXiv:1908.10690},
year = {2020}
}
Comments
Main manuscript with 5 figures plus supplementary information file (including 9 supplementary sections and 14 supplementary figures)