Mapping Modified Electronic Levels in the Moiré Patterns in MoS2/WSe2Using Low-Loss EELS

Sandhya Susarla; Lucas M. Sassi; Alberto Zobelli; Steffi Y. Woo; Luiz H.G. Tizei; Odile Stéphan; Pulickel M. Ajayan

doi:10.1021/acs.nanolett.1c00984

Mapping Modified Electronic Levels in the Moiré Patterns in MoS₂/WSe₂Using Low-Loss EELS

Sandhya Susarla, Lucas M. Sassi, Alberto Zobelli, Steffi Y. Woo, Luiz H.G. Tizei, Odile Stéphan, Pulickel M. Ajayan

Research output: Contribution to journal › Article › peer-review

16 Scopus citations

Abstract

Hybrid/moiré interlayer and intralayer excitons have been realized in twisted two-dimensional transition metal chalcogenides (2D-TMD) due to variation in local moiré potential within a moiré supercell. Though moiré excitons have been detected in TMD heterostructures by macroscopic spectroscopic techniques, their spatial distribution is experimentally unknown. In the present work, using high-resolution scanning transmission electron microscopy (STEM) and electron energy-loss spectroscopy (EELS), we explore the effect of the twist angle in MoS2/WSe2 heterostructures. We observe weak interaction between the layers at higher twist angles (>5°) and stronger interaction for lower twist angles. The optical response of the heterostructure varies within the moiré supercell, with a lower energy absorption peak appearing in regions with the AA stacking.

Original language	English
Pages (from-to)	4071-4077
Number of pages	7
Journal	Nano Letters
Volume	21
Issue number	9
DOIs	https://doi.org/10.1021/acs.nanolett.1c00984
State	Published - May 12 2021
Externally published	Yes

Funding

This material is based upon research supported by the Chateaubriand Fellowship of the Office for Science & Technology of the Embassy of France in the United States. This project was partially funded by the National Agency for Research under the program of future investment TEMPOS-CHROMATEM (reference no. ANR-10-EQPX-50). L.M.S. acknowledges CAPES (Coordination for the Improvement of Higher Education Personnel), sponsored by the Brazilian Ministry of Education, for financial support.

Funders	Funder number
National Agency for Research	ANR-10-EQPX-50
Office for Science and Technology of the Embassy of France in the United States
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Ministério da Educação

Keywords

STEM-EELS
TMDs
moiré excitons
van der Waals heterostructures

Access to Document

10.1021/acs.nanolett.1c00984

Cite this

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title = "Mapping Modified Electronic Levels in the Moir{\'e} Patterns in MoS2/WSe2Using Low-Loss EELS",

abstract = "Hybrid/moir{\'e} interlayer and intralayer excitons have been realized in twisted two-dimensional transition metal chalcogenides (2D-TMD) due to variation in local moir{\'e} potential within a moir{\'e} supercell. Though moir{\'e} excitons have been detected in TMD heterostructures by macroscopic spectroscopic techniques, their spatial distribution is experimentally unknown. In the present work, using high-resolution scanning transmission electron microscopy (STEM) and electron energy-loss spectroscopy (EELS), we explore the effect of the twist angle in MoS2/WSe2 heterostructures. We observe weak interaction between the layers at higher twist angles (>5°) and stronger interaction for lower twist angles. The optical response of the heterostructure varies within the moir{\'e} supercell, with a lower energy absorption peak appearing in regions with the AA stacking.",

keywords = "STEM-EELS, TMDs, moir{\'e} excitons, van der Waals heterostructures",

author = "Sandhya Susarla and Sassi, {Lucas M.} and Alberto Zobelli and Woo, {Steffi Y.} and Tizei, {Luiz H.G.} and Odile St{\'e}phan and Ajayan, {Pulickel M.}",

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T1 - Mapping Modified Electronic Levels in the Moiré Patterns in MoS2/WSe2Using Low-Loss EELS

AU - Susarla, Sandhya

AU - Sassi, Lucas M.

AU - Zobelli, Alberto

AU - Woo, Steffi Y.

AU - Tizei, Luiz H.G.

AU - Stéphan, Odile

AU - Ajayan, Pulickel M.

PY - 2021/5/12

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AB - Hybrid/moiré interlayer and intralayer excitons have been realized in twisted two-dimensional transition metal chalcogenides (2D-TMD) due to variation in local moiré potential within a moiré supercell. Though moiré excitons have been detected in TMD heterostructures by macroscopic spectroscopic techniques, their spatial distribution is experimentally unknown. In the present work, using high-resolution scanning transmission electron microscopy (STEM) and electron energy-loss spectroscopy (EELS), we explore the effect of the twist angle in MoS2/WSe2 heterostructures. We observe weak interaction between the layers at higher twist angles (>5°) and stronger interaction for lower twist angles. The optical response of the heterostructure varies within the moiré supercell, with a lower energy absorption peak appearing in regions with the AA stacking.

KW - STEM-EELS

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KW - van der Waals heterostructures

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