Exciton spectrum in atomically thin monolayers: The role of hBN encapsulation

Abstract

The high-quality structures containing semiconducting transition metal dichalcogenides (S-TMDs) monolayer (MLs) required for optical and electrical studies are achieved by their encapsulation in hexagonal BN (hBN) flakes. To examine the effect of hBN thickness in these systems, we consider a model with an S-TMD ML placed between a semi-infinite in the out-of-plane direction substrate and complex top cover layers: a layer of finite thickness, adjacent to the ML, and a semi-infinite in the out-of-plane direction top part. We obtain the expression for the Coulomb potential for such a structure. Using this result, we demonstrate that the energies of excitonic $s$ states in the structure with WSe${}_2$ ML change significantly for the top hBN with thickness less than 30 layers for different substrate cases, such as hBN and SiO${}_2$. For the larger thickness of the top hBN flake, the binding energies of the excitons are saturated to their values of the bulk hBN limit.

7 pages, 4 figures + SM

References in corpus (9)

• Tightly bound excitons in monolayer WSe2
• Probing Excitonic Dark States in Single-layer Tungsten Disulfide
• Non-linear Optical Spectroscopy of Excited Exciton States for Efficient Valley Coherence Generation in WSe2 Monolayers
• Probing the influence of dielectric environment on excitons in monolayer WSe2: Insight from high magnetic fields
• Magneto-photoluminescence of exciton Rydberg states in monolayer WSe${}_2$
• Luminescent emission of excited Rydberg excitons from monolayer WSe2
• Rydberg series of dark excitons and the conduction band spin-orbit splitting in monolayer WSe${}_2$
• Analogy and dissimilarity of excitons in monolayer and bilayer of MoSe${}_2$
• Magneto-Optical Measurements of the Negatively Charged 2$s$ Exciton in WSe${}_2$

Cited by in corpus (4)

• Dipolar interactions enhanced by two-dimensional dielectric screening in few-layer van der Waals structures
• Twistronics and moiré superlattice physics in 2D transition metal dichalcogenides
• Multidimensional sensing of proximity magnetic fields via intrinsic activation of dark excitons in WSe${}_2$/CrCl${}_3$ heterostructure
• Rydberg series of intralayer K-excitons in WSe${}_2$ multilayers