A5103172745- Semiconductor Quantum Structures and Devices
- ZnO doping and properties
- GaN-based semiconductor devices and materials
- Quantum and electron transport phenomena
- Strong Light-Matter Interactions
- Advanced Semiconductor Detectors and Materials
- DNA and Nucleic Acid Chemistry
- Nanowire Synthesis and Applications
- Semiconductor materials and devices
- Silicon Nanostructures and Photoluminescence
- Advanced Fiber Laser Technologies
- Advanced biosensing and bioanalysis techniques
- Machine Learning in Materials Science
- Nonlinear Optical Materials Research
- Chalcogenide Semiconductor Thin Films
- Advanced Fluorescence Microscopy Techniques
- Ga2O3 and related materials
- Nonlinear Optical Materials Studies
- TiO2 Photocatalysis and Solar Cells
- Photonic and Optical Devices
- Porphyrin and Phthalocyanine Chemistry
- Advanced Photocatalysis Techniques
- Molecular Junctions and Nanostructures
- Quantum Dots Synthesis And Properties
- Thin-Film Transistor Technologies
Institut de Physique et Chimie des Matériaux de Strasbourg
2005-2023
Centre National de la Recherche Scientifique
2002-2023
Université de Strasbourg
2012-2023
Porous silicon grains embedded in the phosphorus doped SiO2 matrix exhibit improved photoluminesce properties and better stability comparison with native porous samples. We have tested this material for presence of room temperature optical amplification under femtosecond (100 fs, 395 nm) excitation. Combined variable stripe length shifted excitation spot experiments reveal positive gain, net modal gain coefficient reaching 25 cm−1 at a pump intensity 1.1 W/cm2 (mean power). The spectrum is...
Silicon nanocrystals (Si-ncs) of sufficiently small size, emitting luminescence at short wavelengths (which implies the occurrence quasi-direct radiative recombination) and being densely packed in a planar thin film ensures stimulated emission (StE) lifetime) can become suitable active material for observation StE visible region. In this paper, we describe fabrication method nanostructures type, based on enhanced electrochemical etching silicon wafers followed by embedding porous grains into...
The ΔP(-)PBS analog of the DNA primary binding sequence (PBS) HIV-1 genome labeled at different positions by 2-aminopurine (2-AP) is investigated a novel femtosecond fluorescence down-conversion experiment with 0.3-ps time resolution. high signal-to-noise ratio kinetics makes it possible to reveal four distinct decay times ranging from 0.8 ps 2–3 ns for all three labeling positions. This suggests existence least quenching conformations 2-AP its nearest neighbors, and underscores structural...
We present experimental results obtained on wurtzite epitaxial GaN layers grown sapphire and SiC substrates. Thanks to a set of samples with different values the residual strain, we demonstrate that high dislocation density enhances spin relaxation rate through Elliott–Yafet mechanism. This fact is validated by T−1 temperature dependence spin-relaxation times. The influence valence-band structure hole-spin also highlighted. In particular, decrease in rate, accompanied strong polarization...
5,11,17,23-Tetranitro-25-[4-[3-(trimethoxysilyl)propylthio]-butyloxy]-26,27,28-tripropyloxycalix[4]arene was prepared and fully characterized using 1H 13C NMR. Elaboration of sol-gel matrix with this macrocycle tetranitrotetrapropoxycalix[4]arene from tetraethoxysilane described. Thin films were obtained these materials studied m-lines spectroscopy, AFM NLO. Chemically grafted exhibited high stable NLO responses.
The photoluminescence emission spectrum at low temperature of the ${\mathrm{TiO}}_{2}$ anatase shows a broad band around 2.3 eV that has been largely attributed to self-trapped excitons. In this paper, time-resolved experiments conducted on thin layer and single crystal give insights into carrier dynamics inside ${\mathrm{TiO}}_{2}$. decay with time can be described by power law from picoseconds range up milliseconds range. rate increases increasing temperature. We propose interpret these...
We performed time‐ and polarization‐resolved pump‐and‐probe experiments on several differently strained GaN wurtzite epilayers.. Thanks to a selective spectral excitation of spin‐polarized A‐excitons at various temperatures fitting procedure considering the different A B spin exciton states, we show that Elliott‐Yafet mechanism is dominant spin‐relaxation process. It origins from high dislocation density in all our epilayers.
By performing non-degenerate pump-probe experiments, we study the relaxation dynamics of spin-polarized A and B excitons in wurtzite epitaxial GaN. We show that spin exciton as a whole is negligible with regard to individual carriers. determined ps for electron conduction band, ps, heavy hole (HH) light (LH), respectively. The quite long HH time can be related band structure which degeneracy between different spin-valence bands lifted.
We study the optical-phonon emission-cascade in ZnCdTe quantum wells governing energy relaxation of electron-hole pairs towards self-organized CdTe/ZnTe islands, which become selectively populated. Using photoluminescence excitation spectroscopy, we determine phonons involved process. evidence moreover coupled exciton-phonon states dots explain trapping and their recombination. a time-resolved pump probe technique, measure variations absorption transmission spectra. thus population dynamics...
We study the electron-hole dynamics of c-plane GaN/AlN quantum dots (QDs) emitting above bulk GaN bandgap [1] by means time-resolved photoluminescence (TRPL) [2]. The PL displays a bi-exponential decay with short time-constant (0.3 ns), independent photon energy, and longer one that follows expected evolution radiative lifetime QD size. attribute fast to non-radiative energy transfer deeper levels, which have sufficiently low density long such their population can be easily saturated. A very...