Search results for "Cathodoluminescence"
showing 10 items of 61 documents
Short-range order and luminescence in amorphous silicon oxynitride
2000
Abstract Using Si 2p core-level X-ray photoelectron spectroscopy, we found that the short-range order in amorphous silicon oxynitride (a-SiOxNy) can be quantitatively described by a random bonding model. Results also show that the second and even further neighbours of the Si in the network affect the chemical shifts of the X-ray photoelectron spectra. Cathodoluminescence and photoluminescence of a-SiOxNy with different compositions are also measured. A red band with energies of 1.8–1.9 eV, a blue band with an energy of 2.7 eV and ultraviolet bands with energies of 13.1, 3.4–3.6, 4.4–4.7 and 5.4eV were observed. The 1.8–1.9 eV band is attributed to the O and N atoms with an unpaired electron…
Time-resolved cathodoluminescence and photoluminescence of nanoscale oxides
2009
The nanostructured oxide materials such as ZnO, ZrO2, and Y3Al5O12 (YAG) are perspective materials for transparent scintillating and/or laser ceramics. The luminescence properties of single crystals, nanopowders and ceramic were compared. Nominally pure and rare-earth doped nanopowders and ceramics have been studied by means of time-resolved luminescence spectroscopy. The fast blue luminescence band was studied in ZnO ceramics sintering from different raw materials. The luminescence centres of ZrO2:Y were compared in a single crystal, ceramic and nanopowder. It is shown that ceramic sintering parameters have a strong influence on time-resolved luminescence characteristics in cerium-doped YA…
Accumulation of radiation defects and modification of micromechanical properties under MgO crystal irradiation with swift 132Xe ions
2020
This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014-2018 and 2019-2020 under grant agreement No. 633053. The views and opinions expressed herein do not necessarily reflect those of the European Commission. A.A. also acknowledges support via the project GF AP05134257 of Ministry of Education and Science of the Republic of Kazakhstan .
Ge-doped silica nanoparticles: production and characterisation
2016
Silica nanoparticles were produced from germanosilicate glasses by KrF laser irradiation. The samples were investigated by cathodoluminescence and scanning electron microscopy, providing the presence of nanoparticles with size from tens up to hundreds of nanometers. The emission of the Germanium lone pair center is preserved in the nanoparticles and atomic force microscopy revealed the presence of no spherical particles with a size smaller than ~4 nm. The absorption coefficient enhancement induced by Ge doping is reputed fundamental to facilitate the nanoparticles production. This procedure can be applied to other co-doped silica materials to tune the nanoparticles features.
Correlative study of structural and optical properties of ZnSe under severe plastic deformation
2019
The effect of plastic deformation on the optical and structural properties of ZnSe crystals has been investigated. The optical properties have been monitored by cathodoluminescence measurements as a function of the deformation degree. Remarkable differences in the defect-related emissions from the most severely deformed areas have been encountered. Deformation of the crystal lattice of ZnSe, associated with slip phenomena, has been studied by means of Electron Backscattered Diffraction and micro-Raman spectroscopy. The relation between the deformation and the optical properties of the ZnSe crystals has been described.
Electronic Band Transitions in γ-Ge3N4
2021
This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014-2018 and 2019-2020 under grant agreement No 633053. The views and opinions expressed herein do not necessarily reflect those of the European Commission. Support from Estonian Research Council grant PUT PRG 619 is gratefully acknowledged. The multi-anvil experiments at LMV were supported by the French Government Laboratory of Excellence initiative no ANR-10-LABX-0006, the Région Auvergne and the European Regional Development Fund (ClerVolc Contribution Number 478).
E-beam induced damage in SiO2–Ge crystalline α-quartz, comparison with silica glass
2005
Electron beam induced transformation in crystalline α-quartz doped with germanium was studied by mean of cathodoluminescence and of phase shift interferometric microscope. E-beams with low current (below 50 nA), defocused (diameter of spot about 40 μm) and with acceleration energy of 15 kV produce swelling of the irradiated volume about 100 nm above the non-irradiated surface. The luminescence of the self-trapped near germanium exciton (GeSTE) is observed mainly. No luminescence of the germanium related oxygen deficient center with bands at 290 and at 395 nm, usual for Ge-doped silica glass (GeODC), was observed. Defocused e-beam with higher current (about 200 nA), the same energy and simil…
Luminescence study of defects in synthetic as-grown and HPHT diamonds compared to natural diamonds
2005
The optically active defects in as-grown, high-pressure high-temperature-treated (HPHT), boron-doped, and synthetic diamonds (SD) grown with a nitrogen-getter, as well as of natural diamonds (ND), were characterized by absorption and luminescence spectroscopies using different excitation sources. The laser-excited photoluminescence (PL) spectra of SDs show numerous sharp lines characteristic for nickel-related centers, whereas NDs yield mainly broad PL bands. The emission from the nickel-related defects in NIR range increases and the maxima of the bands shift to lower energies with increasing temperature. Under UV and electron beam excitation, the yellow synthetic diamonds display green lum…
Cathodoluminescence of oxyfluoride glass-ceramics
2013
Abstract Tb, Ce, Eu activated oxyfluoride glass-ceramics with the composition SiO2 · Al2O3 · Li2O · LaF3 have been studied by cathodoluminescence (CL). We compared CL intensities and decay times of the Tb, Ce, Eu activated glass-ceramic samples and observed that the Tb activated sample has the most intense luminescence, but the Ce activated sample has the shortest decay times. Induced optical absorption and thermostimulated luminescence have been observed after X-ray irradiation of samples.
Cathodoluminescence and structural studies of nitrided 3D gallium structures grown by MOCVD
2009
Abstract Cathodoluminescence (CL) spectrum imaging and grazing incidence X-ray diffraction (GIXRD) are employed to investigate nitride three-dimensional (3D) gallium structures. The metallic precursors are naturally obtained on a large variety of substrates by metal-organic chemical vapor deposition (CVD) with different shape/size controlled by the growth conditions, especially the temperature. These 3D metallic structures are subsequently exposed to a nitridation process in a conventional CVD reactor to form GaN nanocrystals, as confirmed by GIXRD measurements. CL spectroscopy shows visible light emission (2.5–2.8 eV) excited from the GaN in the 3D structures.