Probing moire excitons in MoSe2/WSe2 heterobilayers by combined micro-photoluminescence and lateral force microscopy

Abstract

We study interlayer excitons in MoSe2/WSe2 heterobilayers, by combining lateral force microscopy and micro-photoluminescence spectroscopy. This allows us to correlate the spatial profile of the moir\'e superlattice with the distribution of optically active states accessible to interlayer excitons. In heterostructures where a few degrees twist angle is imposed between the MoSe and WSe crystallographic axes, we show that a continuous moir\'e lattice is realized across areas close to the optical diffraction limit. In such regions, the photoluminescence reduces to a few narrow-band lines only, energetically distributed consistently with the geometry of the moir\'e lattice. This correlation reveals that interlayer excitons explore a controlled periodic confinement, paving the way towards implementations of Bose-Hubbard models.