Signatures of defect-localized charged excitons in the photoluminescence of monolayer molybdenum disulfide
arXiv:1902.06872 · doi:10.1103/PhysRevMaterials.2.124003
Abstract
We study spatial photoluminescence characteristics of neutral and charged excitons across extended monolayer MoS synthesized by chemical vapor deposition. Using two-dimensional hyperspectral photoluminescence mapping at cryogenic temperatures we identify regions with increased emission from charged excitons associated with both spin-orbit split valence subbands. Such regions are attributed to unintentional doping at defect sites with excess charge that bind neutral excitons to form defect-pinned trions. Our findings imply comparable timescales for the formation, relaxation, and radiative decay of trions, and add defect-localized and trions to the realm of photoexcited quasiparticles in layered semiconductors.
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