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arXiv · 2102.06140

Nanoscale modification of WS$_2$ trion emission by its local electromagnetic environment

Noémie Bonnet·Hae Yeon Lee·Fuhui Shao·Steffi Y. Woo·Jean-Denis Blazit·Kenji Watanabe·Takashi Taniguchi·Alberto Zobelli·Odile Stéphan·Mathieu Kociak·Silvija Gradecak-Garaj·Luiz H. G. Tizei
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Abstract

Structural, electronic, and chemical nanoscale modifications of transition metal dichalcogenide monolayers alter their optical properties, including the generation of single photon emitters. A key missing element for complete control is a direct spatial correlation of optical response to nanoscale modifications, due to the large gap in spatial resolution between optical spectroscopy and nanometer resolved techniques, such as transmission electron microscopy or scanning tunneling microscopy. Here, we bridge this gap by obtaining nanometer resolved optical properties using electron spectroscopy, specifically electron energy loss spectroscopy (EELS) for absorption and cathodoluminescence (CL) for emission, which were directly correlated to chemical and structural information. In an h-BN/WS$_2$/h-BN heterostructure, we observe local modulation of the trion (X$^{-}$) emission due to tens of nanometer wide dielectric patches, while the exciton, X$_A$, does not follow the same modulation. Trion emission also increases in regions where charge accumulation occurs, close to the carbon film supporting the heterostructures. Finally, localized exciton emission (L) detection is not correlated to strain variations above 1 $\%$, suggesting point defects might be involved in their formations.

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Noémie Bonnet, Hae Yeon Lee, Fuhui Shao, Steffi Y. Woo, Jean-Denis Blazit, Kenji Watanabe, Takashi Taniguchi, Alberto Zobelli, Odile Stéphan, Mathieu Kociak, Silvija Gradecak-Garaj, Luiz H. G. Tizei. 2021-02-11. Nanoscale modification of WS$_2$ trion emission by its local electromagnetic environment. https://doi.org/10.1021/acs.nanolett.1c02600

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