Impact of substrates and quantum effects on exciton line shapes of 2D semiconductors at room temperature

Abstract

Exciton resonances in monolayer transition-metal dichalcogenides (TMDs) provide exceptionally strong light-matter interaction at room temperature. Their spectral line shape is critical in the design of a myriad of optoelectronic devices, ranging from solar cells to quantum information processing. However, disorder resulting from static inhomogeneities and dynamical fluctuations can significantly impact the line shape. Many recent works experimentally evaluate the optical properties of TMD monolayers placed on a substrate and the line shape is typically linked directly to the material's quality. Here, we highlight that the interference of the substrate and TMD reflections can strongly influence the line shape. We further show how basic, room-temperature reflection measurement allow investigation of the quantum mechanical exciton dynamics by systematically controlling the substrate reflection with index-matching oils. By removing the substrate contribution with a properly chosen oil, we can extract the excitonic decay rates including the quantum mechanical dephasing rate. The results provide valuable guidance for the engineering of exciton line shapes in layered nanophotonic systems.

References in corpus (24)

• Single-Layer MoS2 Phototransistors
• 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
• Electrically Tunable Excitonic Light Emitting Diodes based on Monolayer WSe2 p-n Junctions
• Electrical Control of Two-Dimensional Neutral and Charged Excitons in a Monolayer Semiconductor
• Exciton physics and device application of two-dimensional transition metal dichalcogenide semiconductors
• Excitonic linewidth approaching the homogeneous limit in MoS2 based van der Waals heterostructures : accessing spin-valley dynamics
• Band Gap Engineering with Ultralarge Biaxial Strains in Suspended Monolayer MoS2
• Excitonic linewidth and coherence lifetime in monolayer transition metal dichalcogenides
• Atomically thin quantum light emitting diodes
• Atomically thin p-n junctions based on two-dimensional materials
• 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
• High-Performance Flexible Nanoscale Field-Effect Transistors Based on Transition Metal Dichalcogenides
• High-Specific-Power Flexible Transition Metal Dichalcogenide Solar Cells
• Low-loss composite photonic platform based on 2D semiconductor monolayers
• Electrical Control of Optical Properties of Monolayer MoS${}_2$
• Nanophotonics with 2D Transition Metal Dichalcogenides
• Realization of an atomically thin mirror using monolayer MoSe2
• Hybrid Exciton-Plasmon-Polaritons in van der Waals Semiconductor Gratings
• Giant Gating Tunability of Optical Refractive Index in Transition Metal Dichalcogenide Monolayers
• Near-unity light absorption in a monolayer WS2 van der Waals heterostructure cavity
• Highly Confined In-plane Exciton-Polaritons in Monolayer Semiconductors

Cited by in corpus (4)

• Temperature-dependent excitonic light manipulation with atomically-thin optical elements
• Photonics in Flatland: Challenges and Opportunities for Nanophotonics with 2D Semiconductors
• Quadrupolar and Dipolar Excitons in Bilayer 2$H$-MoSe${}_2$
• Direct measurement of broken time-reversal symmetry in centrosymmetric and non-centrosymmetric atomically thin crystals with nonlinear Kerr rotation