Defect formation processes in the silicon nanoparticles under the neutron irradiation

2019 ◽  
Vol 33 (26) ◽  
pp. 1950315 ◽  
Author(s):  
A. A. Garibli ◽  
A. A. Garibov ◽  
E. M. Huseynov
Keyword(s):  
Cross Section ◽  
Neutron Irradiation ◽  
Silicon Nanoparticles ◽  
Defect Formation ◽  
Formation Processes ◽  
Free Electrons ◽  
Paramagnetic Resonance ◽  
Epithermal Neutrons ◽  
Before And After ◽  
Electron Paramagnetic

Silicon nanoparticles have been irradiated by neutrons up to 20 h. Free electrons and defects in the nanosilicon particles have been comparatively investigated before and after neutron irradiation using electron paramagnetic resonance (EPR) method. The neutron scattering and capture cross-section processes have been calculated for natural [Formula: see text], [Formula: see text], [Formula: see text] isotopes, which are main part of nanosilicon samples when irradiated for 20 h by epithermal neutrons. Particle size, agglomeration and other surface effects of silicon nanoparticles were studied with scanning electron microscope (SEM) before and after neutron irradiation.

The neutron irradiation effects on the temperature dependencies of the electrical conductivity of nanosilicon particles

2017 ◽  
Vol 31 (28) ◽  
pp. 1750257 ◽  
Author(s):  
Elchin Huseynov ◽  
Aydan Garibli
Keyword(s):  
Electrical Conductivity ◽  
Neutron Flux ◽  
Neutron Irradiation ◽  
Silicon Nanoparticles ◽  
Activation Energies ◽  
Radiation Defects ◽  
Irradiation Effects ◽  
Active Radiation ◽  
Before And After ◽  
Effects Of Temperature

The effects of temperature and neutron irradiation on the silicon nanoparticles have been studied at different frequencies. It has been defined that additional electro-active radiation defects occur in the silicon nanomaterial after neutron irradiation. Therefore, the change of neutron flux at the interval of [Formula: see text]–[Formula: see text] increases the conductivity of nanosilicon. Activation energies of the silicon nanoparticles were calculated for 10 different constant frequencies according to Arrhenius approach before and after neutron irradiation. The mechanism of electrical conductivity which explains results has been established.

scholarly journals Investigation of Photoelectron Properties of Polymer Films with Silicon Nanoparticles

Surfaces ◽  
2019 ◽  
Vol 2 (2) ◽  
pp. 387-394 ◽  
Author(s):  
Elizaveta A. Konstantinova ◽  
Alexander S. Vorontsov ◽  
Pavel A. Forsh
Keyword(s):  
Single Crystal ◽  
Silicon Nanoparticles ◽  
Electrochemical Etching ◽  
Nonequilibrium Charge Carrier ◽  
Electric Energy ◽  
Single Crystal Silicon ◽  
Crystal Silicon ◽  
Paramagnetic Resonance ◽  
Carrier Separation ◽  
Electron Paramagnetic

Hybrid samples consisting of polymer poly-3(hexylthiophene) (P3HT) and silicon nanoparticles were prepared. It was found that the obtained samples were polymer matrixes with conglomerates of silicon nanoparticles of different sizes (10–104 nm). It was found that, under illumination, the process of nonequilibrium charge carrier separation between the silicon nanoparticles and P3HT with subsequent localization of the hole in the polymer can be successfully detected using electron paramagnetic resonance (EPR) spectroscopy. It was established that the main type of paramagnetic centers in P3HT/silicon nanoparticles are positive polarons in P3HT. For comparison, samples consisting only of polymer and silicon nanoparticles were also investigated by the EPR technique. The polarons in the P3HT and Pb centers in the silicon nanoparticles were observed. The possibility of the conversion of solar energy into electric energy is shown using structures consisting of P3HT polymer and silicon nanoparticles prepared by different methods, including the electrochemical etching of a silicon single crystal in hydrofluoric acid solution and the laser ablation of single-crystal silicon in organic solvents. The results can be useful for solar cell development.

Thermally reversible γ-ray-induced redox reaction between substitutional iron and aluminum impurity centers in a silica glass

2001 ◽  
Vol 16 (1) ◽  
pp. 127-131 ◽  
Author(s):  
Radhaballabh Debnath
Keyword(s):  
Silica Glass ◽  
Γ Irradiation ◽  
Paramagnetic Resonance ◽  
Hole Trapping ◽  
Oxygen Hole ◽  
Before And After ◽  
Impurity Centers ◽  
Spin Resonances ◽  
Electron Paramagnetic ◽  
Hole Centers

The magnetic properties of the substitutional iron and aluminum impurity centers in a sintered Vycor silica glass were studied before and after 1.1–1.3 MeV γ irradiation. Observation of two overlapping spin resonances (g ∼ 4.20–4.28) in the spectra of both the irradiated and preirradiated glasses indicated the existence of two types of tetra coordinated substitutional iron centers of the [FeO4−/Na+]0 type. The intensity of these electron-paramagnetic resonance (EPR) signals decreased upon g irradiation of the glass with concomitant generation of aluminum hole center [AlO4]0, which was manifested by the occurrence of a new six-line EPR signal with g 4 2.009, while thermal annealing of these aluminum oxygen hole centers restores the intensity of the iron centers almost to their preirradiation level. This result suggests that if not the whole, a major fraction of the electrons released in the process of g-ray-induced hole trapping at the Al site are captured by the substitutional iron centers. The electron traps, thus formed, are quite stable and can be deactivated by thermal stimulation.

Luminescence and EPR Study of Lithium-Diffused ZnO Crystals

2002 ◽  
Vol 744 ◽  
Author(s):  
N. Y. Garces ◽  
Lijun Wang ◽  
M. M. Chirila ◽  
L. E. Halliburton ◽  
N. C. Giles
Keyword(s):  
Room Temperature ◽  
Deep Level ◽  
Chemical Vapor ◽  
Vapor Transport ◽  
Chemical Vapor Transport ◽  
Paramagnetic Resonance ◽  
Lithium Diffusion ◽  
Before And After ◽  
Electron Paramagnetic ◽  
Transport Method

ABSTRACTZinc oxide (ZnO) crystals grown by the seeded chemical vapor transport method have been studied using photoluminescence (PL), thermoluminescence (TL), and electron paramagnetic resonance (EPR) techniques. Lithium acceptors were diffused into the crystals during anneals in LiF powder at temperatures in the 750 to 850°C range. After a lithium diffusion, EPR was used to monitor neutral lithium acceptors and neutral shallow donors, as well as Ni3+, Fe3+, and Cu2+ impurities unintentionally present. Excitonic and deep-level PL emissions were also monitored before and after these diffusions. Two broad overlapping TL emission bands were observed at 117 and 145 K when a Li-diffused crystal was illuminated at 77 K with 325-nm light and then rapidly warmed to room temperature. The two TL bands have the same spectral dependence (the peak in wavelength is 540 nm when the intensity of the light reaches a maximum). These “glow” peaks occur when electrons are thermally released from Ni2+ and Fe2+ ions and recombine with holes at neutral lithium acceptors.

An Experimental Technique for Studying Chemisorption Reactions by Means of Electron Paramagnetic Resonance Spectroscopy

1972 ◽  
Vol 26 (2) ◽  
pp. 239-241 ◽  
Author(s):  
Eugene P. Scheide ◽  
George G. Guilbault
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Experimental Method ◽  
Electron Paramagnetic Resonance Spectroscopy ◽  
Cupric Chloride ◽  
Resonance Spectroscopy ◽  
Epr Spectrum ◽  
Paramagnetic Resonance ◽  
Before And After ◽  
Chemisorption Bond ◽  
Electron Paramagnetic

A new experimental method and a specially designed EPR cell are described for use in the study of chemisorption reactions. By studying the EPR spectrum of a surface both before and after chemisorption, it can be shown whether unpaired d electrons are used in the chemisorption bond and the nature of this bond. The EPR spectra of a cupric chloride surface, both before and after a gaseous ligand (diisopropyl methyl phosphonate) is chemisorbed, are shown and the results are interpreted in terms of the type of bond formed.

scholarly journals Epr Spectrum Angular Dependences In Liyf4 Crystal / Epr Spektru Leņķiskās Atkarības Liyf4 Kristālā

2012 ◽  
Vol 49 (6-I) ◽  
pp. 49-54
Author(s):  
A. Antuzevics ◽  
A. Fedotovs ◽  
U. Rogulis
Keyword(s):  
Room Temperature ◽  
Temperature Analysis ◽  
Epr Spectrum ◽  
Spectral Parameters ◽  
Paramagnetic Resonance ◽  
X Ray ◽  
Crystal Growth Process ◽  
Before And After ◽  
Impurity Ion ◽  
Electron Paramagnetic

Abstract Electron paramagnetic resonance (EPR) measurements have been made for two perpendicular planes in a LiYF4 crystal before and after x-ray irradiation at room temperature. Analysis of the EPR spectrum angular dependence shows the presence of two defects - an impurity ion, which was embedded during the crystal growth process, and an x-ray induced defect with the g-factor of approx. 2.0. Spectral parameters and possible defect models are discussed.

scholarly journals Electron paramagnetic resonance in the research of defect formation and thermal processes during grinding of ZnO powders

2004 ◽  
Vol 36 (2) ◽  
pp. 65-72 ◽  
Author(s):  
M. Kakazey ◽  
M. Vlasova ◽  
M. Dominguez-Patiño ◽  
G. Dominguez-Patiño ◽  
T. Sreckovic ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Mechanical Treatment ◽  
Defect Formation ◽  
Thermal Processes ◽  
Defect Structures ◽  
Paramagnetic Centers ◽  
Paramagnetic Resonance ◽  
Zno Powders ◽  
Electron Paramagnetic

This work shows some possibilities for using electron paramagnetic resonance in an experimental study of the role of mechanothermal effects in the formation of defect structures in dispersed systems during prolonged mechanical treatment of ZnO powders. The use of EPR for this purpose is based on the known fact that initiation of a number of paramagnetic centers occurs during mechanical treatment of some materials. Such centers can serve as EPR-sondes of different thermal processes appearing during mechanical treatment of systems containing ZnO.

Microstructural Evolution of Pb(Zr,Ti)O3 Ceramics Using Electron Paramagnetic Resonance

1993 ◽  
Vol 310 ◽  
Author(s):  
W. L. Warren ◽  
B. A. Tuttle ◽  
R. W. Schwartz ◽  
W. F. Hammetter ◽  
D. C. Goodnow ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Microstructural Evolution ◽  
Lead Zirconate Titanate ◽  
Perovskite Phase ◽  
Lead Zirconate ◽  
Solution Chemistry ◽  
Paramagnetic Resonance ◽  
Before And After ◽  
High Concentrations ◽  
Electron Paramagnetic

AbstractUsing electron paramagnetic resonance (EPR) we have followed the microstructural evolution with temperature of lead zirconate titanate (PZT) ceramics from the amorphous to the perovskite phase. A number of paramagnetic point defects were identified (Carbon, Pb+3, and Ti+3) while traversing the evolution of these ceramics during various heat treatments both before and after optical illumination. Perhaps the most important finding is that the Pb+3 and Ti+3 centers can only be optically created in the perovskite materials, thereby, showing that they are not associated with the amorphous or the pyrochlore phases. It is also found that EPR signals attributed to carbon radicals are present in fairly high concentrations (4 × 1017/cm3) if the solution chemistry derived PZT materials are annealed in an oxygen deficient ambient (0.1% O2) at 650°C.

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