A5075538999- Concrete and Cement Materials Research
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Semiconductor Quantum Structures and Devices
- Mineralogy and Gemology Studies
- Building materials and conservation
- Innovative concrete reinforcement materials
- Cultural Heritage Materials Analysis
- Concrete Properties and Behavior
- Concrete Corrosion and Durability
- Glass properties and applications
- Quantum and electron transport phenomena
- Spectroscopy and Quantum Chemical Studies
- Recycling and utilization of industrial and municipal waste in materials production
- Thin-Film Transistor Technologies
- Magnesium Oxide Properties and Applications
- Theoretical and Computational Physics
- Thermal and Kinetic Analysis
- Quantum Dots Synthesis And Properties
- Photonic Crystals and Applications
- Geological and Geochemical Analysis
- Recycled Aggregate Concrete Performance
- Phase-change materials and chalcogenides
- Conservation Techniques and Studies
- Material Dynamics and Properties
University of Bergen
2024-2025
University of Technology Sydney
2015-2024
Laboratoire de Physique des Interfaces et des Couches Minces
2017-2019
University of Oxford
2019
Kielce University of Technology
2011-2017
University of Bath
2011
The University of Sydney
2010
Philipps University of Marburg
1999-2009
Curtin University
2009
Southern Connecticut State University
2006
We report the study of optical dephazing Wannier-Stark ladder excitations in a semiconductor superlattice by means transient degenerate four-wave mixing. observe pronounced modulations signal with time period varying linearly electric field. The is found to equal temporal periodicity Bloch oscillations, agreement theory. In addition, we find that decreases increasing localization states, which attributed carrier escape out lowest miniband.
Optical spectra in quantum wells are many cases strongly influenced by disorder. In particular, energy relaxation of correlated electron-hole pairs through disorder-induced localized states determines the position and shape photoluminescence lines. By a Monte Carlo simulation approach is studied temperature dependence spectral peak linewidth determined for variety model systems steady-state situation.
We present a Monte Carlo study of the relaxation and dissociation dynamics optical excitations in poly(p-phenylenevinylene). The quantitative comparison with experimental data gives complete picture excitation dynamics, relevant parameters spectral relaxation, trapping processes involved. Our simulations are extended to include primary step neutral photoexcitation an electric field. results field-induced photoluminescence quenching experiments enables us understand determine exciton binding...
We report on the coherent dynamics of excitonic wave packets observed in transient four-wave mixing experiments strained InGaAs/GaAs quantum-well structures. The noneigenstates are created by using laser pulses shorter than electron round trip time within exciton orbital. A characteristic temporal modulation diffracted signal is observed, which resembles an packet a hydrogen atom expected for case simultaneous excitation all bound and lowest continuum states.
Photoluminescence in (GaIn)(NAs) quantum wells designed for laser emission was studied experimentally and theoretically. The observed temperature dependences of the luminescence Stokes shift spectral linewidth evidence essential role disorder dynamics recombining excitations. spatial energy disorders can cause a localization photocreated excitations supposedly form excitons. Theoretical study exciton is performed via kinetic Monte Carlo simulations hopping recombination manifold localized...
Abstract The non‐direct transition model for calculation of amorphous ϵ 2 ‐spectra is considered with respect to energy dependent matrix elements. It shown how these elements may be obtained from the crystalline discussed Selenium, Germanium, and Silicon.
Analytic calculations are carried out for temperature and field dependences of the hopping drift mobility charge carriers in strongly anisotropic disordered solids where transport can be treated as one dimensional. The solutions obtained exact processes with noninteracting carrier transitions to nearest sites a one-dimensional chain. Only such essential systems correlated space-energy distributions localized states [see K. Kohary et al., following paper, Phys. Rev. B 63, 094202 (2001)]....
Percolation approach is used to study the dc hopping conductivity and thermopower in systems with a Gaussian density of localized states typical for disordered organic materials. It shown that theoretical methods developed earlier description transport inorganic solids, such as amorphous semiconductors, can also be successfully applied conjugated or molecularly doped polymers. Calculations within percolation give results excellent agreement those obtained by using more transparent, though...
Interplay between temperature T and high electric field F concerning their influence on the hopping transport in disordered semiconductors is studied theoretically. A series of computer simulations transient steady-state conduction carried out with emphasis verification concept so-called effective temperature. According to this heuristic can be parametrized by a single quantity ${\mathit{T}}_{\mathrm{eff}}$(T,F). We show that such functions ${\mathit{T}}_{\mathrm{eff}}$(T,F) do exist for...
Interaction with both acoustical as well optical phonons contributes to the relaxation of excitons in tail states coherently strained CdTe/ZnTe quantum wells. The contribution is most important thinnest 1.8 monolayers. Hopping down, which involves emission acoustic phonons, leads a redshift luminescence band about 10 meV within first 200 ps after excitation. A comparison experimental data results quantitative theory allows us evaluate concentration localized involved process.
We have performed temperature-dependent studies of the photoluminescence properties a range $\mathrm{In}\mathrm{As}∕\mathrm{Ga}\mathrm{As}$ quantum dot structures. Changes in temperature dependence peak energy and spectral width are governed by thermally stimulated transfer processes hence depend on depth confining potentials. compared our experimental results with detailed calculations based upon correlated electron-hole (exciton) or independent relaxation. conclude that at elevated...
Abstract Infrared spectroscopy has been used to examine changes bone chemistry as a result of soil burial. Pig carcasses were buried part controlled field study, and pig was in environments established the laboratory. The variables species type, pretreatment, type pH , moisture content, temperature, burial time investigated. crystallinity index (CI) organic carbonate contents bones monitored. data revealed decreasing trends an increase CI with time. An acidic environment are factors that...