Near-field spectroscopic imaging of exciton quenching at atomically sharp MoS2/WS2 lateral heterojunctions

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 photoluminesce...

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Bibliographic Details
Published in:Nanoscale 2022-05, Vol.14 (17), p.6323-6330
Main Authors: He-Chun, Chou, Xin-Quan, Zhang, Shiue-Yuan Shiau, Ching-Hang Chien, Po-Wen Tang, Chun-Te Sung, Chang, Yia-Chung, Yi-Hsien, Lee, Chen, Chi
Format: Article
Language:English
Subjects:
Excitation spectra
Excitons
Heterojunctions
Microscopes
Molybdenum disulfide
Monolayers
Near fields
Optical properties
Optical pumping
Photoluminescence
Quenching
Spatial resolution
Stitching
Transition metal compounds
Tungsten disulfide
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Summary: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 WS2/MoS2 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.
ISSN:2040-3364
2040-3372
DOI:10.1039/d2nr00216g