Exciton spectroscopy and unidirectional transport in MoSe2-WSe2 lateral heterostructures encapsulated in hexagonal boron nitride - Archive ouverte HAL Access content directly
Journal Articles npj 2D Materials and Applications Year : 2022

Exciton spectroscopy and unidirectional transport in MoSe2-WSe2 lateral heterostructures encapsulated in hexagonal boron nitride

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Abstract

Chemical vapor deposition (CVD) allows lateral edge epitaxy of transition metal dichalcogenide heterostructures. Critical for carrier and exciton transport is the material quality and the nature of the lateral heterojunction. Important details of the optical properties were inaccessible in as-grown heterostructure samples due to large inhomogeneous broadening of the optical transitions. Here we perform optical spectroscopy of CVD grown MoSe 2 -WSe 2 lateral heterostructures, encapsulated in hBN. Photoluminescence (PL), reflectance contrast and Raman spectroscopy reveal optical transition linewidths similar to high quality exfoliated monolayers, while PL imaging experiments uncover the effective excitonic diffusion length of both materials. The typical extent of the covalently bonded MoSe 2 -WSe 2 heterojunctions is 3 nm measured by scanning transmission electron microscopy (STEM). Tip-enhanced, sub-wavelength optical spectroscopy mapping shows the high quality of the heterojunction which acts as an excitonic diode resulting in unidirectional exciton transfer from WSe 2 to MoSe 2 .
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Dates and versions

hal-03872025 , version 1 (25-11-2022)

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Attribution - CC BY 4.0

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Dorian Beret, Ioannis Paradisanos, Hassan Lamsaadi, Ziyang Gan, Emad Najafidehaghani, et al.. Exciton spectroscopy and unidirectional transport in MoSe2-WSe2 lateral heterostructures encapsulated in hexagonal boron nitride. npj 2D Materials and Applications, 2022, 6 (1), pp.84. ⟨10.1038/s41699-022-00354-0⟩. ⟨hal-03872025⟩
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