Measuring the Exciton Binding Energy: Learning from a Decade of Measurements on Halide Perovskites and Transition Metal Dichalcogenides DOI Creative Commons
Kameron R. Hansen, John Colton, Luisa Whittaker‐Brooks

et al.

Advanced Optical Materials, Journal Year: 2023, Volume and Issue: 12(3)

Published: Oct. 22, 2023

Abstract The exciton binding energy ( E b ) is a key parameter that governs the physics of many optoelectronic devices. At their best, trustworthy and precise measurements challenge theoreticians to refine models, are driving force in advancing understanding material system, lead efficient device design. worst, inaccurate astray, sow confusion within research community, hinder improvements by leading poor designs. This review article seeks highlight pros cons different measurement techniques used determine , namely, temperature‐dependent photoluminescence, resolving Rydberg states, electroabsorption, magnetoabsorption, scanning tunneling spectroscopy, fitting optical absorption. Due numerous conflicting values reported for halide perovskites (HP) transition metal dichalcogenides (TMDC) monolayers, an emphasis placed on highlighting these attempt reconcile variance between techniques. It argued experiments with clearest indicators agreement following values: ≈350–450 meV TMDC monolayers SiO 2 vacuum, ≈150–200 hBN‐encapsulated ≈200–300 common lead‐iodide 2D HPs, ≈10 methylammonium iodide.

Language: Английский

Twist-Angle-Dependent Valley Polarization of Intralayer Moiré Excitons in van der Waals Superlattices DOI
R.Z. Wang, Kai Chang, Wenhui Duan

et al.

Physical Review Letters, Journal Year: 2025, Volume and Issue: 134(2)

Published: Jan. 17, 2025

Twistronics, which utilizes the moiré potential to induce exotic excitations in twisted material systems, has garnered significant attention recent years. In this Letter, using Bethe-Salpeter calculations based on a continuum model of electronic structures, we explore optical characteristics intralayer excitons bilayer transition metal dichalcogenide heterostructures. We find Coulomb exchange interactions strongly influence these and degree valley polarization that splitting between spin-singlet spin-triplet can be effectively controlled by varying twist angle. Specifically, bright confined WSe_{2}/WS_{2} heterostructure achieve levels as high 90% at small angles, holds promise for future applications valleytronics. These findings underscore angle novel parameter manipulating properties excitons, thereby establishing semiconductors promising platform investigating many-body physics solid-state systems.

Language: Английский

Citations

1
Quadrupolar excitons in MoSe2 bilayers DOI Creative Commons
Jakub Jasiński, Joakim Hagel,

Samuel Brem

et al.

Nature Communications, Journal Year: 2025, Volume and Issue: 16(1)

Published: Feb. 5, 2025

Abstract The quest for platforms to generate and control exotic excitonic states has greatly benefited from the advent of transition metal dichalcogenide (TMD) monolayers their heterostructures. Among unconventional states, quadrupolar excitons—a superposition two dipolar excitons with anti-aligned dipole moments—are great interest applications in quantum simulations investigation many-body physics. Here, we unambiguously demonstrate emergence natural MoSe 2 homobilayers, whose energy shifts quadratically electric field. In contrast trilayer systems, homobilayers have many advantages, which include a larger coupling between excitons. Our experimental observations are complemented by many-particle theory calculations offering microscopic insights formation results suggest TMD as ideal platform engineering interaction light thus candidate carrying out on-chip simulations.

Language: Английский

Citations

1
Tuning moiré excitons in Janus heterobilayers for high-temperature Bose-Einstein condensation DOI Creative Commons
Hongli Guo, Xu Zhang, Gang Lü

et al.

Science Advances, Journal Year: 2022, Volume and Issue: 8(40)

Published: Oct. 7, 2022

Using first-principles calculations, we predict that moiré excitons in twisted Janus heterobilayers could realize tunable and high-temperature Bose-Einstein condensation (BEC). The electric dipole the leads to charge-transfer interlayer intralayer with exceptionally long lifetimes, absence of spacer layers. is also expected enhance exciton-exciton repulsions at high exciton densities can modulate potentials trap for their condensation. key parameters condensation, including Bohr radius, binding energy, effective mass, critical Mott density, are examined as a function twist angle. Last, phase diagrams constructed from which one estimate BEC (>100 K) superfluid (~30 transition temperatures. In addition indirect excitons, find direct condense temperatures, consistent experiments.

Language: Английский

Citations

35
Type-II MoSi2N4/MoS2 van der Waals Heterostructure with Excellent Optoelectronic Performance and Tunable Electronic Properties DOI
Xuhui Xu, Lei Yang,

Quan Gao

et al.

The Journal of Physical Chemistry C, Journal Year: 2023, Volume and Issue: 127(16), P. 7878 - 7886

Published: April 12, 2023

van der Waals heterostructures (vdWHs) provide a new strategy to broaden the application of two-dimensional (2D) materials in novel nanodevices. Based on first-principles calculations, we propose 2D MoSi2N4/MoS2 vdWH for light harvesting and photovoltaic applications. The exhibits semiconducting characteristic with an indirect band gap 1.12 eV. type-II alignment facilitates spatial separation photogenerated electron–hole pairs. Therefore, excellent optical absorption (∼105 cm–1) large photocurrent density (1.6 mA cm–2) visible range. Furthermore, performing external electric field biaxial strain can effectively regulate vdWH. Notably, tensile significantly enhances total These findings reveal potential as alternative optoelectronic devices possibilities designing strain-tunable devices.

Language: Английский

Citations

22
Measuring the Exciton Binding Energy: Learning from a Decade of Measurements on Halide Perovskites and Transition Metal Dichalcogenides DOI Creative Commons
Kameron R. Hansen, John Colton, Luisa Whittaker‐Brooks

et al.

Advanced Optical Materials, Journal Year: 2023, Volume and Issue: 12(3)

Published: Oct. 22, 2023

Abstract The exciton binding energy ( E b ) is a key parameter that governs the physics of many optoelectronic devices. At their best, trustworthy and precise measurements challenge theoreticians to refine models, are driving force in advancing understanding material system, lead efficient device design. worst, inaccurate astray, sow confusion within research community, hinder improvements by leading poor designs. This review article seeks highlight pros cons different measurement techniques used determine , namely, temperature‐dependent photoluminescence, resolving Rydberg states, electroabsorption, magnetoabsorption, scanning tunneling spectroscopy, fitting optical absorption. Due numerous conflicting values reported for halide perovskites (HP) transition metal dichalcogenides (TMDC) monolayers, an emphasis placed on highlighting these attempt reconcile variance between techniques. It argued experiments with clearest indicators agreement following values: ≈350–450 meV TMDC monolayers SiO 2 vacuum, ≈150–200 hBN‐encapsulated ≈200–300 common lead‐iodide 2D HPs, ≈10 methylammonium iodide.

Language: Английский

Citations

21