Subnanometric control of coupling between WS$_2$ monolayers with a molecular spacer

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Main Authors: Elrafei, Sara A., Sistermans, Tom T. C., Curto, Alberto G.
Format: Preprint
Published: 2024
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author Elrafei, Sara A.
Sistermans, Tom T. C.
Curto, Alberto G.
author_facet Elrafei, Sara A.
Sistermans, Tom T. C.
Curto, Alberto G.
contents Stacking monolayer semiconductors into heterostructures allows for control of their optical and electronic properties, offering advantages for nanoscale electronics, optoelectronics, and photonics. Specifically, adding a thin spacer between monolayers can yield bulk materials that retain interesting monolayer properties, such as a direct bandgap and a high emission quantum efficiency. The interaction mechanisms between monolayers, including interlayer coupling, charge transfer, and energy transfer, might be tuned through subnanometric control over the spacer thickness. Traditional spacer materials like bulk oxides or other layered materials can suffer from poor material interfaces or inhomogeneous thickness over large areas. Here, we use a spin-cast organic molecular spacer to adjust interlayer coupling in WS$_2$ monolayer stacks. We vary the molecular spacer thickness to tune the interlayer distance, significantly altering the optical properties of the resulting organic-inorganic heterostructures. Additionally, we demonstrate a dependence of the valence-band splitting on molecular spacer thickness manifested as a change in the energy difference between A and B excitons resulting from spin-orbit coupling and interlayer interactions. Our results illustrate the potential of molecular spacers to tailor the properties of monolayer heterostructures. This accessible approach opens new routes to advance atomically thin devices and could enable sensing technologies at the subnanometer scale.
format Preprint
id arxiv_https___arxiv_org_abs_2412_20313
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Subnanometric control of coupling between WS$_2$ monolayers with a molecular spacer
Elrafei, Sara A.
Sistermans, Tom T. C.
Curto, Alberto G.
Mesoscale and Nanoscale Physics
Materials Science
Optics
Stacking monolayer semiconductors into heterostructures allows for control of their optical and electronic properties, offering advantages for nanoscale electronics, optoelectronics, and photonics. Specifically, adding a thin spacer between monolayers can yield bulk materials that retain interesting monolayer properties, such as a direct bandgap and a high emission quantum efficiency. The interaction mechanisms between monolayers, including interlayer coupling, charge transfer, and energy transfer, might be tuned through subnanometric control over the spacer thickness. Traditional spacer materials like bulk oxides or other layered materials can suffer from poor material interfaces or inhomogeneous thickness over large areas. Here, we use a spin-cast organic molecular spacer to adjust interlayer coupling in WS$_2$ monolayer stacks. We vary the molecular spacer thickness to tune the interlayer distance, significantly altering the optical properties of the resulting organic-inorganic heterostructures. Additionally, we demonstrate a dependence of the valence-band splitting on molecular spacer thickness manifested as a change in the energy difference between A and B excitons resulting from spin-orbit coupling and interlayer interactions. Our results illustrate the potential of molecular spacers to tailor the properties of monolayer heterostructures. This accessible approach opens new routes to advance atomically thin devices and could enable sensing technologies at the subnanometer scale.
title Subnanometric control of coupling between WS$_2$ monolayers with a molecular spacer
topic Mesoscale and Nanoscale Physics
Materials Science
Optics
url https://arxiv.org/abs/2412.20313