Disorder of Excitons and Trions in Monolayer MoSe2

Abstract

The optical spectra of transition metal dichalcogenide (TMDC) monolayers are dominated by excitons and trions. Here we establish the dependences of these optical transitions on disorder from hyperspectral imaging of h-BN encapsulated monolayer MoSe2. While both exciton and trion energies vary spatially, these two quantities are almost perfectly correlated, with spatial variation in the trion binding energy of only ~0.18 meV. In contrast, variation in the energy splitting between the two lowest energy exciton states is one order of magnitude larger at ~1.7 meV. Statistical analysis and theoretical modeling reveal that disorder results from dielectric and bandgap fluctuations, not electrostatic fluctuations. Our results shed light on disorder in high quality TMDC monolayers, its impact on optical transitions, and the many-body nature of excitons and trions.

10 pages, 3 figures, 7 pages SI

References in corpus (4)

• STM Spectroscopy of ultra-flat graphene on hexagonal boron nitride
• Many-Body Theory of Trion Absorption Features in Two-Dimensional Semiconductors
• Electron-exciton interactions in the exciton-polaron problem
• A Many-Body Theory of the Optical Conductivity of Excitons and Trions in Two-Dimensional Materials