Harnessing in-plane optical anisotropy in WS₂ through ReS₂ crystal

Nanophotonics, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 30, 2025

Abstract In this work, we explore how the optical properties of isotropic materials can be modulated by adjacent anisotropic materials, providing new insights into light-matter interactions in van der Waals heterostructures. Using a WS 2 /ReS heterostructure, systematically investigated excitation angle-dependent photoluminescence (PL), differential reflectance, time-resolved PL, and power-dependent PL anisotropy . Our findings reveal that response , influenced crystallographically low symmetry unique dielectric environment ReS significantly impacts both temporal behavior We observed emission increases with power density, highlighting localization photo-generated carriers subsequent charge transfer dynamics are key contributors to polarization-sensitive response. These provide framework for leveraging density-sensitive mirroring design advanced optoelectronic photonic devices.

Language: Английский

---

Unusual photocarrier and coherent phonon dynamics behaviors of layered PdSe2 unveiled by ultrafast spectroscopy of the edge surface

Science China Physics Mechanics and Astronomy, Journal Year: 2024, Volume and Issue: 67(8)

Published: July 11, 2024

Language: Английский

---

Lifetime mapping using femtosecond time-resolved photoemission electron microscopy

The Journal of Chemical Physics, Journal Year: 2024, Volume and Issue: 161(17)

Published: Nov. 1, 2024

Time-resolved photoemission electron microscopy (PEEM) has established itself as a versatile experimental technique to unravel the ultrafast dynamics of materials with nanometer-scale resolution. However, approach performing PEEM-based, pixel-by-pixel lifetime mapping not been reported thus far. Herein, we describe in detail data pre-processing procedure and an algorithm perform time-trace fittings each pixel. We impose energy cutoff for pixel prior spectral integration enhance robustness our approach. With cutoff, energy-integrated time traces show improved statistics lower fitting errors, resulting more accurate determination fit parameters, e.g., decay constants. Our work allows us reliably construct PEEM-based maps, which potentially shed light on effects local microenvironment processes material allow spatial distributions lifetimes be correlated observables obtained from complementary microscopic techniques, hence enabling comprehensive characterization material.

Language: Английский

---

Ultrafast photoemission electron microscopy: A multidimensional probe of nonequilibrium physics

Chinese Physics B, Journal Year: 2023, Volume and Issue: 33(3), P. 038703 - 038703

Published: Dec. 20, 2023

Exploring the realms of physics that extend beyond thermal equilibrium has emerged as a crucial branch condensed matter research. It aims to unravel intricate processes involving excitations, interactions, and annihilations quasi- many-body particles, ultimately achieve manipulation engineering exotic non-equilibrium quantum phases on ultrasmall ultrafast spatiotemporal scales. Given inherent complexities arising from dynamics, it therefore seeks technique efficient diverse detection degrees freedom study underlying physics. By combining high-power femtosecond lasers with real- or momentum-space photoemission electron microscopy (PEEM), imaging excited state phenomena multiple perspectives, including time, real space, energy, momentum, spin, can be conveniently achieved, making unique in studying out equilibrium. In this context, we overview working principle technical advances PEEM apparatus related laser systems, survey key excited-state probed through surface-sensitive methodology, dynamics electrons, excitons, plasmons, spins, etc., materials ranging bulk nano-structured metals semiconductors low-dimensional materials. Through review, one further envision time-resolved will open new avenues for investigating variety classical multidimensional parameter offering unprecedented comprehensive insights into important questions field

Language: Английский

---

Potassium hydroxide treatment of layered WSe₂ with enhanced electronic performances

Nanoscale, Journal Year: 2024, Volume and Issue: 16(17), P. 8345 - 8351

Published: Jan. 1, 2024

2D WSe2-based electronic devices have received much research interest. However, it is still a challenge to achieve high performance in devices. In this work, we report greatly enhanced performances of different thickness WSe2 ambipolar transistors and demonstrate homogeneous inverter devices, which are obtained by using semiconductor processing-compatible layer removal technique via chemical the surface top WOx formed O2 plasma treatment. Importantly, monolayer was realised after several consecutive processes, demonstrating that single accurate reliable. After subsequent KOH, fabricated field-effect exhibit along with electron hole mobilities 40 85 cm2 V-1 s-1, respectively. Our work demonstrates an efficient route fabricate material-based

Language: Английский

---

Polarization Anisotropy of Ultrafast Electronic Dynamics in AB‐Stacked Rhenium Disulfide

Advanced Electronic Materials, Journal Year: 2024, Volume and Issue: unknown

Published: June 17, 2024

Abstract Revealing transient electronic properties in anisotropic 2D materials is a prerequisite for developing ultrafast optoelectronic functional devices. Here, the dynamics of polarization anisotropy AB‐stacked rhenium disulfide (ReS 2 ) are studied using time‐ and energy‐resolved photoemission electron microscopy. The relaxation process exhibits sensitive layer‐dependent anisotropy. linear dichroism also measured, indicating that determined by fast on sub‐picosecond scale. With ab initio theory calculations, it confirmed ultra‐sensitive layer dependence lifetime originates from stronger interlayer coupling K‐Γ direction (along b‐axis) ReS . Further, analyzing time‐resolved energy spectrum, distinct “fast” “slow” regimes found excited electrons with different energies. corresponding windows show substantial anisotropy, which associated electron‐phonon This work has implications design angle‐sensitive devices

Language: Английский

---

Spatial-temporal imaging electronic dynamics in few-layer graphene

2D Materials, Journal Year: 2024, Volume and Issue: 12(1), P. 011002 - 011002

Published: Dec. 11, 2024

Abstract Revealing the ultrafast carrier dynamics with spatial, energy and time resolution is critical for achieving a comprehensive understanding of electronic two-dimensional (2D) materials heterostructures. Here, by time-resolved photoemission electron microscopy (Tr-PEEM) measurements, we reveal layer-dependent monolayer (1 ML), bilayer (2 4 ML graphene as well bulk graphite. In contrast to 2 thicker graphene, photo-excited electrons in 1 relax much faster, which attributed unique massless linear Dirac cone dispersion, allowing continuously emitting phonons. Moreover, transient photoelectron redistribution shows an shift between highlighting role bandgap on relaxation dynamics. Our work demonstrates power Tr-PEEM revealing 2D heterostructures spatial-temporal information, provides information few-layer graphene.

Language: Английский

---