Near-field spectroscopic imaging of exciton quenching at atomically sharp MoS 2 /WS 2 lateral heterojunctions.
He-Chun ChouXin-Quan ZhangShiue-Yuan ShiauChing-Hang ChienPo-Wen TangChun-Te SungYia-Chung ChangYi-Hsien LeeChi ChenPublished in: Nanoscale (2022)
Heterojunctions made by laterally stitching two different transition metal dichalcogenide monolayers create a unique one-dimensional boundary with intriguing local optical properties that can only be characterized by nanoscale-spatial-resolution spectral tools. Here, we use near-field photoluminescence (NF-PL) to reveal the narrowest region (105 nm) ever reported of photoluminescence quenching at the junction of a laterally stitched WS 2 /MoS 2 monolayer. We attribute this quenching to the atomically sharp band offset that generates a strong electric force at the junction to easily dissociate excitons. Besides the sharp heterojunction, a model considering various widths of the alloying interfacial region under low or high optical pumping is presented. With a spatial resolution six times better than that of confocal microscopy, NF-PL provides an unprecedented spectral tool for non-scalable 1D lateral heterojunctions.
Keyphrases
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