Time-resolved photoemission electron microscopy of semiconductor interfaces

Progress in Surface Science, Journal Year: 2024, Volume and Issue: 99(3), P. 100745 - 100745

Published: April 26, 2024

Semiconductor interfaces are at the heart of functionality many devices for opto-electronic applications. At these interfaces, importance ultrafast dynamics – processes that occur on sub-nanosecond timescales has been long understood. While spectroscopic studies have revealed important information, there remains a rich array physics is hidden within sub-micrometer length scales when using spatially-averaged techniques. However, powerful tools could access material in semiconductors simultaneously time- and challenging to implement. Here, we review recent developments time-resolved photoemission electron microscopy as technique study semiconductor nanoscale. In particular, work traditional heterojunctions, low-dimensional materials, photovoltaic

Language: Английский

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Ultrafast energizing the parity-forbidden dark exciton in black phosphorus

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

Published: April 29, 2025

As conventional electronic materials approach their physical limits, the application of ultrafast optical fields to access transient states matter captures imagination. The inversion symmetry governs parity selection rule, differentiating between accessible and inaccessible matter. To circumvent parity-forbidden transitions, common practice is break by material design or external fields. Here we report how femtosecond ultraviolet pulses can energize a dark exciton state in black phosphorus while maintaining its intrinsic symmetry. Unlike bandgap absorption visible-to-infrared, excitation turns on efficient Coulomb scattering, promoting carrier multiplication heating ~3000 K, consequently populating states. Interferometric time- angle-resolved two-photon photoemission spectroscopy reveals dynamics ~100 fs time scale anisotropic wavefunctions energy-momentum space, illuminating potential applications optoelectronics photochemistry under excitation.

Language: Английский

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Spatiotemporal imaging and manipulation of surface plasmons

Nanophotonics, Journal Year: 2024, Volume and Issue: 13(11), P. 1985 - 1992

Published: Jan. 10, 2024

Abstract Surface plasmon polaritons (SPPs) are travelling surface waves that have shown promise for applications in nanophotonics as they provide a direct route toward photon-mediated electrical signal generation – central paradigm speeding up and scaling down photonic elements. SPP also generated fundamental interest due to their high-field strength sub-wavelength confinement, properties enabled the surface-enhanced Raman effect. Over last decade, photoemission electron microscopy (PEEM) has emerged pioneering technique imaging electric fields through ultrashort laser pulse mediated emission therefore become an indispensable tool characterizing plasmonic phenomena at interfaces variety of materials. PEEM offers nanometer spatial resolution femtosecond temporal resolution, allowing SPPs be prepared, monitored, manipulated on nanometer-femtosecond scale. Through brief review recent reports, we aim introduce PEEM-based manipulation modalities highlight utility context emerging nanoscale quantum materials science advancements.

Language: Английский

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Probing excitons with time-resolved momentum microscopy

Advances in Physics X, Journal Year: 2024, Volume and Issue: 9(1)

Published: July 26, 2024

Excitons – two-particle correlated electron-hole pairs are the dominant low-energy optical excitation in broad class of semiconductor materials, which range from classical silicon to perovskites, and two-dimensional organic materials. The study excitons has been brought on a new level detail by application photoemission momentum microscopy technique that dramatically extended capabilities time- angle resolved spectroscopy. Here, we review how photoelectron detection scheme enables direct access energy landscape bright dark excitons, and, more generally, momentum-coordinate exciton wavefunction. Focusing materials semiconductors, first discuss typical fingerprint highlight it is possible obtain information not only electron- but also hole-component. Second, focus recent orbital tomography such this provides unique real-space properties We studies performed transition metal dichalcogenides semiconductors lead very similar conclusions, manner, strength for excitations semiconductors.

Language: Английский

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Nonperturbative quantum theory of multiplasmonic electron emission from surfaces: Gauge-specific cumulant expansions vs. Volkov ansatz over plasmonic coherent states

Progress in Surface Science, Journal Year: 2025, Volume and Issue: unknown, P. 100768 - 100768

Published: April 1, 2025

Language: Английский

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Imaging surfaces at the space–time limit: New perspectives of time-resolved scanning tunneling microscopy for ultrafast surface science

Progress in Surface Science, Journal Year: 2023, Volume and Issue: 99(1), P. 100727 - 100727

Published: Nov. 3, 2023

Language: Английский

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The impact of a dopant atom on the distribution of hot electrons and holes in Au-doped Ag nano-clusters

Physical Chemistry Chemical Physics, Journal Year: 2024, Volume and Issue: 26(15), P. 12168 - 12178

Published: Jan. 1, 2024

The generation of hot carriers (HCs) through the excitation localized surface plasmon resonance (LSPR) in metal nanostructures is a fascinating phenomenon that fuels both fundamental and applied research.

Language: Английский

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Resonant four-photon photoemission from SnSe2(001)

Frontiers of Physics, Journal Year: 2023, Volume and Issue: 19(3)

Published: Dec. 18, 2023

Language: Английский

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Adsorption and electronic structure of submonolayer Ca on Ag(111)

Physical review. B./Physical review. B, Journal Year: 2024, Volume and Issue: 110(7)

Published: Aug. 2, 2024

By frequency-time spectroscopy, microscopy, and electronic structure theory, we investigate the low coverage adsorption of Ca on an Ag(111) surface. The chemisorption alkaline-earth atoms starting from their closed $4{s}^{2}$ shell configuration differs that open $n{s}^{1}$ alkali-metal because they retain some $4s$ electron charge can involve hybridization with low-lying unoccupied $3d$ orbitals. Spectroscopic investigation by three-photon photoemission (3PP) reveals states dominant 3d-orbital character, as confirmed theory. Coverage-specific spectral features enable attribution to two distinct phases at submonolayer coverages, which are atomic scale scanning tunneling microscopy spectroscopy measurements. Furthermore, time-resolved 3PP a resonant two-photon transition between occupied $(\ensuremath{\sim}\ensuremath{-}0.3 \mathrm{eV})$ $(\ensuremath{\sim}2.7 s- $d$-orbital character. Interferometric measurements probing this resonance reveal dephasing time $\ensuremath{\sim}21$ fs population lifetime $\ensuremath{\sim}52$ for transiently populated $d$-like state $\ensuremath{\sim}2.7$ eV above ${E}_{F}$. Contrary atom chemisorption, characteristic development importance adsorbate Ag substrate interactions cause low-coverage condensation into compact islands. Discovery long-lived $d$-character informs catalytic optoelectronic applications element Ca.

Language: Английский

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Time-resolved photoelectron spectroscopy at surfaces

Surface Science, Journal Year: 2024, Volume and Issue: 753, P. 122631 - 122631

Published: Nov. 1, 2024

Language: Английский

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