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

Abstract

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.

20 pages, 5 figures

References in corpus (22)

• Van der Waals heterostructures
• Boron nitride substrates for high-quality graphene electronics
• Exciton Binding Energy and Nonhydrogenic Rydberg Series in Monolayer WS2
• Observation of giant bandgap renormalization and excitonic effects in a monolayer transition metal dichalcogenide semiconductor
• Vertical Field Effect Transistor based on Graphene-WS2 Heterostructures for flexible and transparent electronics
• Tunable Photoluminescence of Monolayer MoS2 via Chemical Doping
• Strong interlayer coupling in van der Waals heterostructures built from single-layer chalcogenides
• Photovoltaic effect in an electrically tunable van der Waals heterojunction
• Optical signature of symmetry variations and spin-valley coupling in atomically thin tungsten dichalcogenides
• Exciton Binding Energy of Monolayer WS2
• Evolution of Interlayer Coupling in Twisted MoS2 Bilayers
• Excitonic linewidth approaching the homogeneous limit in MoS2 based van der Waals heterostructures : accessing spin-valley dynamics
• Picosecond photoresponse in van der Waals heterostructures
• Electronic Properties of Graphene Encapsulated with Different Two-Dimensional Atomic Crystals
• Thickness-Dependent Differential Reflectance Spectra of Monolayer and Few-Layer MoS2, MoSe2, WS2 and WSe2
• Design of van der Waals Interfaces for Broad-Spectrum Optoelectronics
• Light-Matter Coupling in Scalable Van der Waals Superlattices
• Disentangling the effects of doping, strain and defects in monolayer WS2 by optical spectroscopy
• Tailoring the dielectric screening in WS${}_2$-graphene heterostructures
• Tutorial: Exciton resonances for atomically-thin optics
• Approaching the absorption limit with monolayer semiconductor superlattices
• Strong Effects of Interlayer Interaction on Valence-Band Splitting in Transition Metal Dichalcogenides