Vacancy-oxygen Complexes Research Articles

Particle transport simulation and effect analysis of CCD irradiated by protons

Monte Carlo method is used to calculate the energy deposition of proton-irradiated scientific CCD (charge coupled device) structure, and the radiation damage mechanism of the device is analyzed by combining the proton irradiation with the annealing experiments. The ionizing dose in gate oxide layer and the displacement damage dose in silicon deposition are simulated. During irradiation and annealing experiments two main parameters, dark signal and charge transfer efficiency, are investigated. Results show that variations of dark signal and charge transfer efficiency are the same as those with ionizing dose and displacement damage dose. During irradiation, dark signal rises obviously as the fluence of 10 MeV proton increases. Defects and their annealing temperature:the divacancy levels show little annealing effect below 300℃, while the oxygen-vacancy complex is stable up to 350℃, and the phosphorous-vacancy has a characteristic annealing temperature of 150℃. Interface states are annealed totally at 175℃. So the annealing only affects oxide-trapped-charges. Dark signal is greatly reduced after annealing, this phenomenon means that the dark signal is mainly affected by ionization. The surface dark signal proportion of the total dark signal can be calculated by the reduction of dark signal during annealing and this is at least 80% or more. As the fluence of 10 MeV proton increases, the charge transfer efficiency reduces obviously. After annealing, the recovery of charge transfer efficiency changes very little, so the charge transfer efficiency is unaffected by oxide-trapped-charges, since it is reduced due mainly to bulk defects. The final device damage will always be proportional to the amount of initial damage and also to the electrical effect on the device. Hence NIEL scaling implies a universal relation:device damage=kdamage×displacement damage dose, where kdamage is a damage constant depending on the device and the parameter affected, and the displacement damage dose (DD) is the product of the NIEL and the particle fluence. MULASSIS is used to calculate the displacement damage dose in depletion area of P-area and deduce kdamage by combining with the experimental value of charge transfer efficiency; kdamage is calculated to be about 3.50×10-14. The formula for degradation degree of charge transfer efficiency is CTEafter irradiated = 1-Dd×kdamage, this formula is used to estimated CTE and the result is compared with the value from experiment. It is shown that the simulated data is in agreement with the experimental data.

The Interaction of Impurity Oxygen with Radiation Defects in Silicon Crystal

Present paper describes the investigation of vacancy (V) and interstitial (I) annihilation on oxygen atoms by means of infrared (IR) absorption and Hall-effect measurements of the accumulation of vacancy-oxygen complexes (VO) in Si crystals at high energy electron irradiation. Silicon samples, containing along with isolated oxygen atoms, more complicated oxygen quasi-molecules of SiOn (n = 1, 2, 3…) type, were used. At isochronal and isothermal annealing in the temperature range of 300°C - 350°C, apart from the reaction of vacancy capturing by oxygen atoms with formation of A-centers, more complicated reactions with participation of vacancies and oxygen atoms were observed: A-centers, oxygen containing quasi-molecules. A model is suggested to describe the observed processes that are qualitatively different from those taking place in samples containing completely dissociated oxygen.

Kinetics study of vacancy–oxygen‐related defects in monocrystalline solar silicon

In this work, diffusion and dissociation mechanisms related to the formation and evolution of vacancy–oxygen complexes have been studied. Czochralski‐grown silicon samples have been irradiated at room temperature using fast electrons resulting in the formation of several defects including vacancy–oxygen complexes (VO). The samples were isothermally annealed at different temperatures in the range of 370–470 C. Fourier‐transform infrared spectroscopy has been employed to measure the local vibrational modes associated with the individual defects. The evolution and generation kinetics of vacancy–oxygen complexes have been simulated within the framework of the theory for diffusion‐limited reactions and compared with the experimental data.

Graphene activating room-temperature ferromagnetic exchange in cobalt-doped ZnO dilute magnetic semiconductor quantum dots.

Control over the magnetic interactions in dilute magnetic semiconductor quantum dots (DMSQDs) is a key issue to future development of nanometer-sized integrated "spintronic" devices. However, manipulating the magnetic coupling between impurity ions in DMSQDs remains a great challenge because of the intrinsic quantum confinement effects and self-purification of the quantum dots. Here, we propose a hybrid structure to achieve room-temperature ferromagnetic interactions in DMSQDs, via engineering the density and nature of the energy states at the Fermi level. This idea has been applied to Co-doped ZnO DMSQDs where the growth of a reduced graphene oxide shell around the Zn(0.98)Co(0.02)O core turns the magnetic interactions from paramagnetic to ferromagnetic at room temperature, due to the hybridization of 2p(z) orbitals of graphene and 3d obitals of Co(2+)-oxygen-vacancy complexes. This design may open up a kind of possibility for manipulating the magnetism of doped oxide nanostructures.

Using the methods of radiospectroscopy (EPR, NMR) to study the nature of the defect structure of solid solutions based on lead zirconate titanate (PZT).

The nature of intrinsic and impurity point defects in lead zirconate titanate (PZT) ceramics has been explored. Using electron paramagnetic resonance (EPR), nuclear magnetic resonance (NMR), and X-ray photoelectron spectroscopy (XPS) methods, several impurity sites have been identified in the materials, including the Fe(3+)-oxygen vacancy (VO) complex and Pb ions. Both of these centers are incorporated into the PZT lattice. The Fe(3+) –VО paramagnetic complex serves as a sensitive probe of the local crystal field in the ceramic; the symmetry of this defect roughly correlates with PZT phase diagram as the composition is varied from PbTiO3 to PbZrO3. NMR spectra (207)Pb in PbTiO3, PbZrO3, and PZT with iron content from 0 to 0.4 wt% showed that increasing the iron concentration leads to a distortion of the crystal structure and to improvement of the electrophysical parameters of the piezoceramics. This is due to the formation of a phase which has a higher symmetry, but at high concentrations of iron (>0.4 wt%), it leads to sharp degradation of electrophysical parameters.

Positron annihilation study of vacancy-type defects in fast-neutron-irradiated MgO·nAl2O3

The positron lifetimes of fast-neutron-irradiated MgO·nAl2O3 single crystals were measured to investigate the formation of cation vacancies. Al monovacancy was possibly observed in samples irradiated by fast neutrons at ultra-low temperatures. Additionally, vacancy-oxygen complex centers were possibly observed in samples irradiated at higher temperatures and fast neutron fluences. Coincidence Doppler broadening (CDB) spectra were measured to obtain information regarding the vicinity of vacancy-type defects. A peak at approximately 11 ×10−3m0c was observed, which may be due to the presence of oxygen atoms in the neighborhood of the vacancies.

EPR study of the hydrogen center in HPHT diamonds grown in carbonate medium

An electron paramagnetic resonance (EPR) study of synthetic diamond crystals grown at HTHP conditions in the carbonate medium Na2CO3CO2H2OC has revealed a hydrogen‐containing center (VOH) along with centers OX1, OX2, and OX3 tentatively associated with oxygen. In the X‐band EPR spectra, the forbidden transitions of the center are superimposed on the allowed HFS lines of one hydrogen atom. We have succeeded in analysis of the allowed transitions in Q‐band experiments. On the basis of the obtained experimental data a hypothetical model of the center has been proposed as a vacancy–oxygen complex with incorporated hydrogen atom. The occurrence of hydrogen in the studied diamond crystals is supported by the presence of CH vibrations in the IR spectra in the range of 3000 cm−1.

Spin-dependent recombination involving oxygen-vacancy complexes in silicon

Spin-dependent relaxation and recombination processes in $\gamma$-irradiated $n$-type Czochralski-grown silicon are studied using continuous wave (cw) and pulsed electrically detected magnetic resonance (EDMR). Two processes involving the SL1 center, the neutral excited triplet state of the oxygen-vacancy complex, are observed which can be separated by their different dynamics. One of the processes is the relaxation of the excited SL1 state to the ground state of the oxygen-vacancy complex, the other a charge transfer between $^{31}$P donors and SL1 centers forming close pairs, as indicated by electrically detected electron double resonance. For both processes, the recombination dynamics are studied with pulsed EDMR techniques. We demonstrate the feasibility of true zero-field cw and pulsed EDMR for spin 1 systems and use this to measure the lifetimes of the different spin states of SL1 also at vanishing external magnetic field.

Anion (Fluoride)-Doped Ceria Nanocrystals: Synthesis, Characterization, and Its Catalytic Application to Oxidative Coupling of Benzylamines

Fluoride doping in the CeO2 lattice has been achieved by a simple, reliable, reproducible, and safe solution-based method. F-containing CeO2 has retained the fluorite structure, and its effect has been confirmed from various analytical techniques such as powder X-ray diffraction, Fourier transform IR, Raman, UV-visible diffuse reflectance, photoluminescence (PL), and X-ray photoelectron spectroscopy (XPS), scanning electron microscopy-energy-dispersive X-ray (EDX) and transmission electron microscopy-EDX analysis. The concentration of fluoride in the CeO2 lattice has been determined from chemical analysis and core-level XPS analysis. The concentration of Ce(3+) in the F-doped and undoped CeO2 samples have been determined both from XPS analysis as well as from variable-temperature magnetic susceptibility measurements. The characteristic Ce(3+) emission in the PL spectrum indicated the increase of Ce(3+) ion concentration in the F-doped sample, conforming to the results from XPS and magnetic measurements. F-doped CeO2 nanocrystals showed moderate monodispersity as determined from particle-size measurements using dynamic light scattering experiments and high surface area of 106.1 m(2)/g. Optical band gap of CeO2 has narrowed upon doping with fluoride ions from 3.05 to 2.95 eV. The formation of extrinsic oxygen vacancy complexes upon F-doping has been observed in the Raman spectrum (at 1097 cm(-1)) in addition to fingerprint bands of CeO2. The UV-shielding property and photocatalytic inactivity toward aqueous dye degradation process of F-doped CeO2 has suggested its potential use in cosmetic applications. Both F-doped CeO2 and CeO2 have been used as catalysts for oxidative coupling of benzylamines to imines in the presence of molecular oxygen under solvent-free conditions. F-doped CeO2 exhibited better catalytic efficiency than CeO2. The oxidation procedure using these catalysts is simple, environmentally benign, and solvent-free, and the catalysts are reusable.

Metastable Cu<i>V</i>O* Complex in Silicon

The reaction of the mobile interstitial Cui atom and the A-center (vacancy-oxygen complex) was recently reported to produce at 350 K the rather stable CuVO complex. Chemomechanical polishing in a copper-contaminated slurry allowed to lower the copper in-diffusion temperature down to 295K. The development of the CuVO complex is shown to proceed via formation of the metastable precursor (CuVO*) which introduces two deep levels in the lower half of the band gap. The CuVO* defect is unstable at room temperature and transforms completely into the CuVO complex by a 30 min anneal at 350 K. The proposed structure for the CuVO* complex of a Cui atom trapped nearby the A-center is supported by recent ab-initio calculations.

Influence of isotopic composition of natural silicon on local vibrational modes of vacancy-oxygen complexes

Various approaches are used to determine the position of the local vibrational modes (LVM) of 28Si–16Os–29Si and 28Si–16Os–30Si quasimolecules (Os is a substitutional oxygen atom). An analysis of published data serves as a basis for determining the geometry (internal angle α = 62°) of the Si–Os–Si quasimolecule and the interaction mass m * = 4.035 amu, and the isotopic shifts of the LVM: 1.6 cm−1 for 28Si–16Os–29Si and 3.1 cm−1 for 28Si–16Os–30Si relative to the basic band of 28Si–16Os–28Si near 835.8 cm−1. A statistical approach is used to calculate the relative intensity of the absorption bands for the different isotopic modifications of the structural unit Si–Os–Si in natural silicon. The isotopic shifts of the corresponding modes are estimated by fitting the shape of the absorption band for the vacancy-oxygen complex in irradiated Si crystals.

Electron Paramagnetic Resonance Probed Defects in the Colossal Dielectric Constant Perovskite CaCu3Ti4O12

A small unknown signal, which shifts down linearly with temperature, was found by measuring electron paramagnetic resonance spectra in the colossal dielectric constant material CaCu3Ti4O12. This signal can be attributed to hopping electrons in CaCu3Ti4O12. In addition, the main Cu2+ signal split into two for the sample sintered in oxygen atmosphere. This may be due to the oxygen absorption into the crystal. Detailed analysis suggests that a copper–oxygen vacancy complex may be responsible for hopping conduction and oxygen absorption in CaCu3Ti4O12.

Effect of Germanium Doping on Thermal Evolution of Neutron Irradiation Induced Defects in Czochralski Si

In this paper, the impact of germanium (Ge) doping on thermal evolution of neutron-induced defects in Czochralski (CZ) silicon has been investigated. It is found that more vacancy-oxygen (VO) defects are generated in Ge-doped Czochralski (GCZ) silicon after fast neutron irradiation. This is ascribed to the promoted vacancy production and retarded vacancy annihilation caused by the large-sized Ge atoms, which lead to an increased equilibrium vacancy concentration and VO complex generation. FTIR measurements found the IR bands of vacancy-oxygen-related complexes in GCZ silicon almost copy their counterparts in CZ silicon, which implies that Ge-doping has little influence on the final states of the evolution of VO complexes. This is also verified by the variations of interstitial oxygen concentrations in CZ and GCZ silicon after isothermal annealing at 800 °C for up to 144 h. However, the evolution process may be somewhat retarded in GCZ silicon, which is caused by the continuous vacancy trapping and releasing.

Effects of annealing temperature on buried oxide precipitates in He and O co-implanted Si

The effects of the processing conditions on the formation of buried oxide precipitates in He and O co-implanted Si were investigated by the combination of Fourier transform infrared (FTIR) absorption spectroscopy, depth-resolved positron annihilation Doppler spectroscopy, and transmission electron microscopy (TEM). Silicon wafers were implanted with 50 keV He ions at a fluence of 2 × 1016 cm−2 and subsequent 150 keV O ions at a fluence of 2 × 1017 cm−2. For comparison, reference Si wafers were only implanted with 150 keV O ions. The Si–O–Si stretching frequency increases while the peak width of the Si–O–Si stretching absorption band decreases with an increase in annealing temperature. After the same annealing, the peak width of the Si–O–Si stretching absorption band in the He and O co-implanted sample is significantly larger than that in the reference sample. Two kinds of vacancy-type defects are observed by positrons, i.e., vacancy-type defects and vacancy-oxygen complexes. The characteristic S values of vacancy-type defects and vacancy-type complexes in the He and O co-implanted sample are smaller than those of the reference sample. In addition, the thickness of the buried oxide layer in the He and O co-implanted sample is smaller than that in the reference sample. After annealing at 1473 K, the O content is larger in the He and O co-implanted sample compared to that in the reference sample.

Defect mediated reversible ferromagnetism in Co and Mn doped zinc oxide epitaxial films

We have introduced defects in ZnO (undoped and doped with Co and Mn) epitaxial thin films using laser irradiation from nanosecond laser pulses and thermal annealing in oxygen ambient. In contrast to the as grown samples, the laser irradiated films show a significant increase in conductivity, enhancement in UV emission, while maintaining the same wurtzite crystal structure. Room-temperature ferromagnetism (RTFM) is observed in laser-irradiated samples, which increased with the number of laser pulses up to a certain value where magnetic moment saturates. The induced ferromagnetism as well as the enhanced electrical conductivity can be reversed with thermal annealing in oxygen ambient. The magnetization in Co and Mn doped films was found to be strong function of growth conditions and defect concentration. X-ray diffraction and optical absorption experiments suggested a 2+ valance state and tetrahedral coordination for both Co and Mn ions. There is a simultaneous increase in n-type electrical conductivity with the number of laser pulses and continue to exhibit semiconducting behavior in both undoped and doped films. The saturation magnetization was found to be 0.08 μB/Co and 0.05 μB/Mn, much lower than 3.0 μB/Co and 5.0 μB/Mn, indicating the prominent role of intrinsic defects in RTFM with some contribution from Co2+-oxygen vacancy complexes. We propose a unified mechanism based upon introduction of intrinsic defects to explain RTFM and n-type conductivity enhancements during pulsed laser and thermal annealing.

Nature of optical transitions involving cation vacancies and complexes in AlN and AlGaN

Photoluminescence spectroscopy was employed to probe the nature of optical transitions involving Al vacancy (VAl) and vacancy-oxygen complex (VAl-ON) in AlN. An emission line near 2 eV due to the recombination between the 2− charge state of (VAl-ON)2−/1−, and the valence band was directly observed under a below bandgap excitation scheme. This photoluminescence (PL) band was further resolved into two emission lines at 1.9 and 2.1 eV, due to the anisotropic binding energies of VAl-ON complex caused by two different bonding configurations–the substitutional ON sits along c-axis or sits on one of the three equivalent tetrahedral positions. Moreover, under an above bandgap excitation scheme, a donor-acceptor pair like transition involving shallow donors and (VAl-ON)2−/1− deep acceptors, which is the “yellow-luminescence” band counterpart in AlN, was also seen to split into two emission lines at 3.884 and 4.026 eV for the same physical reason. Together with previous results, a more complete picture for the optical transitions involving cation vacancy related deep centers in AlGaN alloy system has been constructed.

Ferromagnetism induced by oxygen-vacancy complex in (Mn, in) codoped ZnO

Mn doped Zinc oxide (ZnO) thin films were prepared by metal organic chemical vapor deposition (MOCVD) technique. Structural characterizations by X-ray diffraction technique (XRD) and photoluminescence (PL) indicate the crystal quality of ZnO films. PL and Raman show a large fraction of oxygen vacancies (VO2+) are generated by vacuum annealed the film. The enhancement of ferromagnetism in post-annealed (Mn, In) codoped ZnO could result from VO2+ incorporation. The effect of VO2+ on the magnetic properties of (Mn, In) codoped ZnO has been studied by first-principles calculations. It is found that only In donor cannot induce ferromagnetism (FM) in Mn-doped ZnO. Besides, the presence of VO2+ makes the Mn empty 3d-t2g minority state broadened, and a t2g-VO2+ hybrid level at the conduction band minimum forms. The presence of VO2+ can lead to strong ferromagnetic coupling with the nearest neighboring Mn cation by BMP model based on defects reveal that the ferromagnetic exchange is mediated by the donor impurity state, which mainly consists of Mn 3d electrons trapped in oxygen vacancies.

Solid state NMR investigation of oxygen dynamics in scandium doped ceria in 50 K to 1073 K temperature range

In this work we investigate the solubility of scandium in ceria, and present a detailed investigation of oxygen dynamics in 0.5% scandium doped ceria from 50K to 1073K by 45Sc solid state NMR line shape, chemical shift, and spin-lattice relaxation analysis. We show that oxygen vacancy is strongly attached to the scandium in the seven-coordinated scandium–oxygen vacancy complex (7-Sc), but even at room temperature the vacancy is moving freely around the scandium atom between eight equivalent sites in millisecond time scale. The activation energy of that vacancy jump is 0.37eV. The eight-coordinated (8-Sc) scandium ion retains cubic environment down to 50K. The exchange rate between 7-Sc and 8-Sc sites exceeds 103Hz above T>600K.

The Ferroelectric and Magnetic Properties of Sol-Gel-Derived (Bi$_{0.85}$Eu$_{0.15}$FeO$_{3}$/Bi$_{3.2}$Y$_{0.8}$Ti$_{3}$O$_{12}$) Bilayer Thin Films

The Bi <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.85</sub> Eu <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.15</sub> FeO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> /Bi <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3.2</sub> Y <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.8</sub> Ti <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">12</sub> bilayer thin films were prepared on Pt(111)/Ti/SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> /Si(100) substrates using the sol-gel process and annealed by rapid thermal annealing in various annealing environments (ambient atmosphere and oxygen). The multiferroic/ferroelectric bilayer thin films were composed of 0.8-μ m thickness Bi <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.85</sub> Eu <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.15</sub> FeO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> and 0.2-μ m thickness of Bi <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3.2</sub> Y <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.8</sub> Ti <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">12</sub> thin film. The effects of annealing atmospheres (ambient atmosphere and oxygen) on the growth and properties of thin films were investigated. The results show that the intensities of the (117) diffraction peak of Bi <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3.2</sub> Y <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.8</sub> Ti <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">12</sub> film and (110) diffraction peak of Bi <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.85</sub> Eu <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.15</sub> FeO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> annealed in oxygen is stronger than those annealed in an ambient atmosphere. The Bi <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.85</sub> Eu <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.15</sub> FeO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> /Bi <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3.2</sub> Y <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.8</sub> Ti <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">12</sub> bilayer thin films annealed in the oxygen atmosphere exhibit the maximum remanent polarization (2\mbi <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">P</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">r</sub> ) and remnant magnetization (2Mr) of 26 μ C/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and 3.44 emu/g, respectively. The improved magnetic and ferroelectric properties can be attributed to the elimination of defects, such as oxygen vacancy and vacancy complexes.

Accumulation of VO Defects in N-Si at High-Temperature Pulse Electron Irradiation: Generation and Annealing Kinetics, Dependence on Irradiation Intensity

Accumulation kinetics of vacancy-oxygen (VO) complexes in Czochralski (Cz) n-Si at 360 °C and 1 MeV electron pulse irradiation has been investigated. It is shown that during the irradiation and simultaneous generation and annealing of VO centers, the accumulation kinetics has non-linear dependence with saturation. It is found that there is a maximal concentration of VO centers, which depends on the radiation intensity (J) and temperature as well. It is also established the annealing of VO centers can substantially be stimulated by the intensity of electron irradiation. An increase of J from 1.25×1015 to 1.25×1016 electrons/(сm2s) does not influence the generation efficiency of VO, though it accelerates their annealing by more than one order of magnitude.