Moiré excitons in MoSe$_2$-WSe$_2$ heterobilayers and heterotrilayers

Abstract

We report experimental and theoretical studies of excitons in twisted stacks of MoSe 2 -WSe 2 heterobilayers and heterotrilayers. We observe distinct optical signatures for the heterobilayer and heterotrilayer regions of a MoSe 2 -WSe 2 heterostack, and interpret our experimental findings in the framework of moiré modulated momentum direct and indirect interlayer excitons. Our results highlight the role of interlayer hybridization for exciton relaxation and formation in multi-layered semiconductor van der Waals heterostructures.

Interlayer Excitonic Spectra of Vertically Stacked MoSe2/WSe2 Heterobilayers

“…Additionally, the differences in local stacking order have been shown to affect the interlayer exciton binding energies, oscillator strengths, and optical selection rules 54 . Based on magneto-luminescence experiments, a recent study suggested that the interlayer PL peaks in twisted MoSe 2 /WSe 2 heterobi-and trilayer systems in R registry arise from moiré potential modulated momentum-direct and phonon-assisted momentum-indirect interlayer exciton emissions, respectively 55 .…”