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Attosecond transient absorption spectroscopy (ATAS) has emerged as a powerful technique within the field of attosecond science, combining extremely high temporal and excellent spectral resolution. So far, ATAS has been implemented in…

Direct and inverse Auger scattering are amongst the primary processes that mediate the thermalization of hot carriers in semiconductors. These two processes involve the annihilation or generation of an electron-hole pair by exchanging…

The ultrafast relaxation and recombination dynamics of photogenerated electrons and holes in epitaxial graphene are studied using optical-pump Terahertz-probe spectroscopy. The conductivity in graphene at Terahertz frequencies depends on…

Mesoscale and Nanoscale Physics · Physics 2015-05-13 Paul A. George , Jared Strait , Jahan Dawlaty , Shriram Shivaraman , Mvs Chandrashekhar , Farhan Rana , Michael G. Spencer

The evolution of charge carriers in photoexcited room temperature ZnO nanoparticles in solution is investigated using ultrafast ultraviolet photoluminescence spectroscopy, ultrafast Zn K-edge absorption spectroscopy and ab-initio molecular…

One-dimensional nanoscale devices, such as semiconductor nanowires (NWs) and single- walled carbon nanotubes (SWNTs), have been intensively investigated because of their potential application of future high-speed electronic, optoelectronic,…

Instrumentation and Detectors · Physics 2014-10-27 B. H. Son , Jae-Ku Park , J. T. Hong , Ji-Yong. Park , Soonil. Lee , Y. H. Ahn

The route towards manipulation of the optoelectronic properties of matter beyond the current limits of electronics starts from a comprehensive study of the ultrafast dynamics triggered by interaction with light. Among them, a fundamental…

The polarization discontinuity across interfaces in polar nitride-based heterostructures can lead to the formation of two-dimensional electron and hole gases. In the past, the observation of these electron and hole gases has been achieved…

Ultrafast Electron Microscopy (UEM) has been demonstrated to be an effective table-top technique for imaging the temporally-evolving dynamics of matter with subparticle spatial resolution on the time scale of atomic motion. However, imaging…

Optics · Physics 2017-08-02 M. Th. Hassan , J. S. Baskin , B. Liao , A. H. Zewail

We investigate theoretically charge migration following prompt double ionization of a polyatomic molecule (C$_2$H$_4$BrI) and find that for double ionization, correlation-driven charge migration appears to be particularly prominent, i.e.,…

Chemical Physics · Physics 2016-05-24 Maximilian Hollstein , Robin Santra , Daniela Pfannkuche

In condensed matter, scattering processes determine the transport of charge carriers. In case of heterostructures, interfaces determine many dynamic properties like charge transfer and transport and spin current dynamics. Here we discuss…

Directly imaging structural dynamics involving hydrogen atoms by ultrafast diffraction methods is complicated by their low scattering cross-sections. Here we demonstrate that megaelectronvolt ultrafast electron diffraction is sufficiently…

We study the ultrafast dynamics of surface electromagnetic waves photogenerated on aluminum film perforated with subwavelength holes array by means of transient photomodulation with 100 fs time resolution. We observed a pronounced blueshift…

Materials Science · Physics 2009-11-13 A. S. Kirakosyan , M. Tong , T. V. Shahbazyan , Z. V. Vardeny

The perturbation of a semiconductor from the thermodynamic equilibrium often leads to the display of nonlinear dynamics and formation of spatiotemporal patterns due to the spontaneous generation of competing processes. Here, we describe the…

Materials Science · Physics 2019-09-16 Ebrahim Najafi , Amir Jafari , Bolin Liao , Ahmed Zewail

Atomic-scale disorder shapes the potential energy landscape traversed by photoexcited charge carriers, while the carriers themselves also dynamically reshape this landscape. However, resolving ultrafast photocarrier motion at atomic length…

Mesoscale and Nanoscale Physics · Physics 2026-04-29 Vedran Jelic , Kaedon Cleland-Host , Stefanie Adams , Mohamed Hassan , Austin Hayes , Tyler L. Cocker

We report the fabrication and characterization of an electrostatic quantum dot in pure Germanium with an integrated charge measurement transistor. The device uses the Al2O3/Germanium interface for the confinement of carriers in the…

Mesoscale and Nanoscale Physics · Physics 2010-09-01 G. Mazzeo , E. Yablonovitch , H. W. Jiang

Germanium arsenide (GeAs) is a layered semiconductor with remarkably anisotropic physical, thermoelectric and optical properties, and a promising candidate for multifunctional devices based on in-plane polarization dependent response.…

We theoretically study how time- and angle-resolved photoemission spectroscopy can be applied for imaging coherent electron dynamics in molecules. We consider a process in which a pump pulse triggers coherent electronic dynamics in a…

Optics · Physics 2018-12-11 Daria Popova-Gorelova , Jochen Küpper , Robin Santra

The dynamics of charge carriers in amorphous semiconductors fundamentally differ from those in crystalline semiconductors due to the lack of long-range order and the high defect density. Despite intensive technology-driven research…

Materials Science · Physics 2017-10-11 Bolin Liao , Ebrahim Najafi , Heng Li , Austin J. Minnich , Ahmed H. Zewail

High harmonic generation (HHG) in solids reflects the underlying nonperturbative nonlinear dynamics of electrons in a strong light field and is a powerful tool for ultrafast spectroscopy of electronic structures. Photo-carrier doping allows…

The femtosecond evolution of the electronic temperature of laser-excited gold nanoparticles is measured, by means of ultrafast time-resolved photoemission spectroscopy induced by extreme-ultraviolet radiation pulses. The temperature of the…