Exciton-Carrier Scattering in Gallium Selenide

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Dataset for the work titled: Long-term protection of crystalline zinc phosphide (Zn₃P₂) under atmospheric conditions This dataset contains experimental measurement data and analysis files used to generate the figures of the associated publication. It includes raw and modeled spectroscopic ellipsometry data, X-ray diffraction (XRD), Raman spectroscopy, secondary-ion mass spectrometry (SIMS), X-ray photoelectron spectroscopy (XPS), and photoluminescence data. The data are organized by manuscript figure and

Uranium oxides occur in a variety of phases that differ in their crystal structure and uranium oxidation states. Electron energy loss spectroscopy (EELS) is one of the few techniques that has sufficient spatial resolution and sensitivity to electronic structure to distinguish among phases at the nanoscale. However, beam-sensitive materials, such as uranium oxides, are subject to spectral modification due to interactions with the electron beam. Therefore, theory support is essential to reliably exclude the i

The electron self-interaction problem in density functional theory affects the accurate modeling of polarons, particularly their localization and formation energy. Charged and neutral density functional formulations have been developed to address this issue, yet their relationship remains unclear. Here, we demonstrate their equivalence in treating the many-body self-interaction of the polaron state. In particular, we connect with each other piecewise-linear functionals based on adding an extra charge to the

Spatial and temporal light modulation is a well-established technology that enables dynamic shaping of the phase and amplitude of optical fields, significantly enhancing the resolution and sensitivity of imaging methods. Translating this capability to electron beams is highly desirable within the framework of a transmission electron microscope (TEM) to benefit from the nanometer spatial resolution of this instrument. In this work, we report on the experimental realization of a photonic-based free-electron m

Electrons and phonons constitute the most fundamental degrees of freedom in the material world, underpinning the technological applications that have shaped everyday life. This thesis explores the emerging electron and phonon physics in novel materials, demonstrating the failure of many conventional treatments and common approximations. The first part develops the theoretical toolbox for modelling microscopic electron and phonon interactions as well as their transport. Specifically, we introduce a robust an

Spacecraft electrostatic discharge is a type of surface discharge in vacuum which is commonly known as vacuum surface flashover, posing a significant threat to the safe operation of spacecraft solar cells. This numerical study investigates vacuum surface flashover on spacecraft solar cells triggered by an inverted potential gradient (IPG), using particle-in-cell simulations. Incorporating the realistic solar cell structure [room temperature vulcanized (RTV) adhesive, cover glass, and metal interconnector] a

We have investigated the electronic response of single crystals of indium selenide by means of angle-resolved photoemission spectroscopy, electron energy loss spectroscopy and density functional theory. The loss spectrum of indium selenide shows the direct ...

The structural incommensurate modulation (SIM) rule in hexagonal Ba(Ti1-xMx)O3-delta (1/18

The aim of this work was to develop a controllable route to produce a stable and inorganic layer on the surface of multi-wall carbon nanotubes. Precursor compounds such as TiBr4, TiCl4, Ti(OiPr)(4), and Ti(OEt)(4) were used to cover the surface of carbon nanotubes (CNTs) under either solvent free or solution conditions. Various titania precursors were compared in the formation of homogeneous layers on the surface of CNTs. As-prepared titania coverages were characterized by transmission electron microscopy (

The growth dynamics of oxygen assisted focused electron beam induced deposition of Si-containing materials (from SiOxCy to SiO2) were investigated as a function of relevant process parameters. The results obtained from organosilanes of different families (alkoxy, alkyl, and isocyanatosilanes) are compared. Residual water molecules in the SEM chamber were found to be responsible for side reactions leading to carbon etching and oxygen incorporation in focused electron beam induced deposition (FEBID) materials

Over the past fifteen years dye-sensitised nanocrystalline solar cells have been the subject of intense research and development efforts. These systems provide a technically and economically credible alternative to classical p-n junction solar cells, reaching over 10 % certified efficiency under standard solar illumination conditions (AM 1.5, 1000 W/m2). Recently, the liquid electrolyte, commonly used in these dye-sensitised solar cells, could successfully be replaced by a novel solid hole-conducting materi

Nanostructured materials can be defined as those materials whose structural elements - clusters, crystallites or molecules - have dimensions in the 1-100 nm range. The explosion in both academic and industrial interest over the past 20 years arises from the remarkable variations in fundamental electrical, optical and magnetic properties that occur as one progresses from an "infinitely extended" solid to a particle of material consisting of a countable number of atoms. In this work the attention was laid on

Information for phase identification may be gathered in the electron transmission microscope with spatial resolution down to the nanometre scale. Energy dispersive X-ray and electron energy loss spectrometries are based on inelastic electron/sample interaction. They have the advantage to give a direct knowledge of the chemical nature of the atoms under the electron probe, sometimes also with valence and bonding, but concentrations are mean values over all atoms in the excited volume that may be insufficient

The formation mechanisms, structure and optoelectronic properties of Ga(In)As/(Al)GaAs quantum dot (QD) heterostructures grown by organometallic chemical vapor deposition on patterned (111)B GaAs substrates are reviewed. With this approach, it is possible to prepare high-quality semiconductor QDs whose position on a substrate is precisely controlled via a pre-growth photolithography step. The dots are formed at the center of an inverted, tetrahedral pyramid and are surrounded by distinct, low-dimensional ba

We report on a study of pentacene thin-films grown by high vacuum deposition on silicon dioxide, using atomic force microscopy (AFM) and transmission electron microscopy (TEM). The nucleation density of pentacene islands on SiO2is found to rise as the deposition rate is increased but decreases at higher substrate temperature. This observation is consistent with the predictions of the rate-equation formalism for homogeneous nucleation. Hence, by controlling the two deposition parameters we are abl

Dye-sensitised nanocrystalline solar cells are currently subject of intense research in the framework of renewable energies as a low-cost photovoltaic device. In particular dye-sensitised cells based on spiro-MeOTAD have gained attention as promising approach towards an organic solid-state solar cell. However, the efficiency in such dye-sensitised solid-state solar devices (SSD) was so far only ca. 10 % of the values reported at AM1.5 for the classical dye-sensitised solar cell with an electrolyte hole tran

The role of Coulomb scattering is studied in the coherent transients of strongly driven exciton resonances in semiconductor quantum wells. Coulomb scattering is treated within the second Born approximation and the light-induced dressing of the electron-hole gas is consistently included. The light dressing is found to decrease the Coulomb collision efficiency and therefore the field-driven dynamics is close to the Hartree-Fock case. Indeed, Coulomb relaxation and dephasing are not strong enough to prevent a

We report on time-resolved and steady-state photoluminescence studies of GaAs/AlGaAs V-groove quantum wire structures. Steady-state photoluminescence experiments are performed in the temperature range from 8 to 200 It. We evaluate the relation between photoluminescence excitation and absorption and determine experimentally the optical density in order to analyze the temperature dependence of the photoluminescence spectra. We find that, at a temperature above 60 K, the photoexcited electron-hole pairs reach

Photoinduced electron transfer from organic dye molecules to semiconductor nanoparticles is the first and most important reaction step for the mechanism in the so called “wet solar cells” [1]. The time scale between the photoexcitation of the dye and the electron injection into the conduction band of the semiconductor colloid varies from a few tens of femtoseconds to nanoseconds, depending on the specific electron transfer parameters of the system, e.g., electronic coupling or free energy values of donor an

The initial dynamics of resonantly excited secondary emission from quantum wells are dominated by Rayleigh scattering due to excitons localized in the disordered quantum well potential. We show experimentally and theoretically how the temporal shape of the early response is related to details of the two-dimensional disorder potential, and we determine the mean amplitude of the fluctuations and the correlation length. Spectral interferometry performed with a. single speckle allows to investigate the phase of

Exciton-Carrier Scattering in Gallium Selenide

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DATASET for Long-term protection of crystalline zinc phosphide (Zn3P2) under atmospheric conditions

Fingerprinting Uranium Oxides with Electron Energy Loss Spectroscopy Supported by Theoretical Computations

Equivalence of charged and neutral density functional formulations for correcting the many-body self-interaction of polarons

Realization of a Pre-Sample Photonic-Based Free-Electron Modulator in Ultrafast Transmission Electron Microscopes

Thermodynamics and Exotic Transport Phenomena in Emerging Materials

Numerical investigation of vacuum surface flashover triggered by inverted potential gradient on solar cells using particle-in-cell method

Indium selenide: an insight into electronic band structure and surface excitations

Structural incommensurate modulation rule in hexagonal Ba(Ti1-xMx)O3-delta (M = Mn, Fe) multiferroics

Preparation of homogeneous titania coatings on the surface of MWNTs

Oxygen assisted focused electron beam induced deposition of Si-containing materials: Growth dynamics

Nanoparticle sensitisation of solid-state nanocrystalline solar cell

Manganese doped ZnS nanoparticles : synthesis, particle sizing and optical properties

Identification of nano-phases: relative merit of local analysis techniques (HRTEM, nanodiffraction, EDS/EELS)

Site- and energy-controlled pyramidal quantum dot heterostructures

Nucleation and growth of ultrathin pentacene films on silicon dioxide: effect of deposition rate and substrate temperature

Interface engineering in solid-state dye-sensitized solar cells

Coherence versus Coulomb scattering in resonantly excited quantum wells

Photoluminescence study of V-groove quantum wires: The influence of disorder on the optical spectra and the carrier thermalization

Ultrafast photoinduced electron transfer in coumarin 343 sensitized TiO2-colloidal solution

Excitonic dephasing effects studied by time- and phase-resolved secondary emission