Dependence of the hBN Layer Thickness on the Band Structure and Exciton Properties of Encapsulated WSe2 Monolayers

Abstract

The optical properties of two-dimensional transition metal dichalcogenide monolayers such as MoS${}_2$ or WSe${}_2$ are dominated by excitons, Coulomb bound electron-hole pairs. Screening effects due the presence of hexagonal-BN surrounding layers have been investigated by solving the Bethe Salpeter Equation on top of GW wave functions in density functional theory calculations. We have calculated the dependence of both the quasi-particle gap and the binding energy of the neutral exciton ground state E${}_b$ as a function of the hBN layer thickness. This study demonstrates that the effects of screening at this level of theory are more short-ranged that it is widely believed. The encapsulation of a WSe${}_2$ monolayer by three sheets of hBN (around 1 nm) already yields a 20 % decrease of E${}_b$ whereas the maximal reduction is 27% for thick hBN. We have performed similar calculations in the case of a WSe${}_2$ monolayer deposited on stacked hBN layers. These results are compared to the recently proposed Quantum Electrostatic Heterostructure approach.

7 pages, 4 figures, correct bibliography, update of Fig.3

References in corpus (24)

• Excitons in atomically thin transition metal dichalcogenides
• Observation of giant bandgap renormalization and excitonic effects in a monolayer transition metal dichalcogenide semiconductor
• Tightly bound excitons in monolayer WSe2
• Probing Excitonic Dark States in Single-layer Tungsten Disulfide
• Excitonic Effects on the Optical Response of Graphene and Bilayer Graphene
• Non-linear Optical Spectroscopy of Excited Exciton States for Efficient Valley Coherence Generation in WSe2 Monolayers
• Probing excitonic states in ultraclean suspended two-dimensional semiconductors by photocurrent spectroscopy
• Unfolding spinor wavefunctions and expectation values of general operators: Introducing the unfolding-density operator
• Magneto-Optics of Exciton Rydberg States in a Monolayer Semiconductor
• Probing the influence of dielectric environment on excitons in monolayer WSe2: Insight from high magnetic fields
• Atomically thin mirrors made of monolayer semiconductors
• The dielectric impact of layer distances on exciton and trion binding energies in van der Waals heterostructures
• Realization of an atomically thin mirror using monolayer MoSe2
• The Coulomb interaction in monolayer transition-metal dichalcogenides
• Environmentally-Sensitive Theory of Electronic and Optical Transitions in Atomically-Thin Semiconductors
• Optical spectroscopy of excited exciton states in MoS2 monolayers in van der Waals heterostructures
• Engineering of Neutral Excitons and Exciton Complexes in Transition Metal Dichalcogenide Monolayers through External Dielectric Screening
• Substrate screening effects on the quasiparticle band gap and defect charge transition levels in MoS${}_2$
• Interlayer excitons in transition metal dichalcogenide heterostructures
• Singlet and triplet trions in WS${}_2$ monolayer encapsulated in hexagonal boron nitride
• Influence of the effective layer thickness on the groundstate and excitonic properties of transition-metal dichalcogenide systems
• Spatial extent of the excited exciton states in WS${}_2$ monolayers from diamagnetic shifts
• Electrostatics of electron-hole interactions in van der Waals heterostructures
• Frequency-dependent substrate screening of excitons in atomically thin transition metal dichalcogenide semiconductors

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• Exciton-Scattering-Induced Dephasing in Two-Dimensional Semiconductors
• Autoionization and dressing of excited excitons by free carriers in monolayer WSe2
• Stacking-Dependent Optical Properties in Bilayer WSe2
• Stacking-dependent exciton multiplicity in WSe${}_2$ bilayers
• A doping-dependent switch from one- to two-component superfluidity at temperature above 100K in coupled electron-hole Van der Waals heterostructures
• First principles coupled cluster theory of the electronic spectrum of the transition metal dichalcogenides
• Optical and dielectric properties of MoO${}_3$ nanosheets for van der Waals heterostructures
• Control of the exciton valley dynamics in van der Waals heterostructures
• Magnetoexcitons in transition-metal dichalcogenides monolayers, bilayers, and van der Waals heterostructures
• Exciton spectrum in atomically thin monolayers: The role of hBN encapsulation
• Persistence of charge ordering instability to Coulomb engineering in the excitonic insulator candidate TiSe${}_2$
• Origin of interlayer exciton-phonon coupling in 2D heterostructures
• Interplay of vibrational, electronic, and magnetic states in CrSBr
• Strain-Enabled Giant Second-Order Susceptibility in Monolayer WSe${}_2$
• Shedding light on the monolayer-WSe2 exciton's nature by optical effective-mass measurements
• Optical Measurement of Pseudo-Spin Texture of the Exciton Fine-Structure in Monolayer WSe2 within the Light Cone