scholarly journals Образование радиационных дефектов в слабо легированных слоях n- и p-SiC при торможении протонов

Author(s):  
В.В. Козловский ◽  
А.Э. Васильев ◽  
П.А. Карасев ◽  
А.А. Лебедев

AbstractMathematical simulation of the cascade of displacements in SiC is used to consider the specific features of Frenkel-pair generation upon the scattering of 8- and 15-MeV protons. The distribution histograms of energies acquired not only by primary knocked-out atoms, but also by recoil atoms generated in displacement cascades, are calculated. An analysis of the histograms considers two energy ranges. In the first range of “low” energies, the spontaneous recombination of genetically related Frenkel pairs is dominant. Recoil atoms in the second range have a higher energy, which enables these atoms to leave the spontaneousrecombination zone and dissociate into isolated components. The compensation of lightly doped n - and p -4 H -SiC samples grown by gas-phase epitaxy is experimentally studied under irradiation with 8- and 15-MeV protons. The carrier removal rates are measured. The calculated and experimental data are compared and estimates are obtained for the size of the spontaneous-recombination zone.

2013 ◽  
Vol 740-742 ◽  
pp. 369-372
Author(s):  
Alexander M. Ivanov ◽  
Alexander A. Lebedev ◽  
V.V. Kozlovski

The irradiation with 0.9 MeV electrons and with 8 MeV and 15 MeV protons were performed for studying radiation defects. Proton scattering in a silicon carbide film has been numerically simulated. Distribution histograms of the energy imparted to recoil atoms are obtained. Two energy ranges are considered when analyzing the histograms. In the first range of “low” energies, individual Frenkel pairs with closely spaced components are created. In the second range, recoil atoms have energies sufficient for generating a cascade of displacements. This gives rise to microscopic regions with high density of vacancies and vacancy complexes of various kinds.


1986 ◽  
Vol 51 (6) ◽  
pp. 1222-1239 ◽  
Author(s):  
Pavel Moravec ◽  
Vladimír Staněk

Expression have been derived in the paper for all four possible transfer functions between the inlet and the outlet gas and liquid steams under the counter-current absorption of a poorly soluble gas in a packed bed column. The transfer functions have been derived for the axially dispersed model with stagnant zone in the liquid phase and the axially dispersed model for the gas phase with interfacial transport of a gaseous component (PDE - AD). calculations with practical values of parameters suggest that only two of these transfer functions are applicable for experimental data evaluation.


1991 ◽  
Vol 56 (10) ◽  
pp. 2020-2029
Author(s):  
Jindřich Leitner ◽  
Petr Voňka ◽  
Josef Stejskal ◽  
Přemysl Klíma ◽  
Rudolf Hladina

The authors proposed and treated quantitatively a kinetic model for deposition of epitaxial GaAs layers prepared by reaction of trimethylgallium with arsine in hydrogen atmosphere. The transport of gallium to the surface of the substrate is considered as the controlling process. The influence of the rate of chemical reactions in the gas phase and on the substrate surface on the kinetics of the deposition process is neglected. The calculated dependence of the growth rate of the layers on the conditions of the deposition is in a good agreement with experimental data in the temperature range from 600 to 800°C.


1989 ◽  
Vol 54 (11) ◽  
pp. 2933-2950
Author(s):  
Emerich Erdös ◽  
Petr Voňka ◽  
Josef Stejskal ◽  
Přemysl Klíma

This paper represents a continuation and ending of the kinetic study of the gallium arsenide formation, where a so-called inhomogeneous model is proposed and quantitatively formulated in five variants, in which two kinds of active centres appear. This model is compared both with the experimental data and with the previous sequence of homogeneous models.


1984 ◽  
Vol 38 ◽  
Author(s):  
Harold F. Winters ◽  
J. W. Coburn

AbstractAn understanding of etching reactions in a plasma environment requires a knowledge of: (1) the types of gas phase particles which react at the surface, (2) the etch products formed, and (3) the processes which lead from reactants to products. Experimental data relavant to these topics are reviewed in this paper. A conceptual framework for understanding the etching reaction is reviewed and it is shown that the experimental data presently available is consistent with this framework. The influence of ion bombardment on etching reactions is extensively discussed.


2019 ◽  
Vol 202 ◽  
pp. 06002
Author(s):  
Stefan Ropertz ◽  
Christoph Hanhart ◽  
Bastian Kubis

We present a new parametrization for scattering amplitudes and form factors, which is consistent with high-accuracy dispersive representations at low energies but at the same time allows for a data description of higher mass resonances such as the f0(1500) and f0(2020). The formalism is general and thus can be applied to many decay processes. As an example we discuss the decay of $ \bar {B}_s^0 $ → J/ψππ(KK). From the amplitude fixed in a fit to the experimental data pole positions and residues are extracted via Padé approximants.


2002 ◽  
Vol 46 (11-12) ◽  
pp. 203-208
Author(s):  
K. Fujisaki ◽  
M. El-Zahar

A mathematical model that describes a batch flotation process is presented. The model employed a similar method to the hindered settling of flocculated material. This idea is based on our experimental results that the time growth curves of separated liquor zone showed a similar character to the settling curve of flocculated material, when the vertical axis reversed. In this model, it is also assumed that the gas phase and solid phase have the same movement, that is microbubbles and solid sludge particles joined to form aggregated floc. By comparing the numerical prediction with experimental data, the usefulness of the model is confirmed and some examples of flotation simulation are demonstrated.


Author(s):  
S. S. Koussa

A model for the prediction of the distribution of soot concentration in spray combustors is presented. Both gas-phase and liquid-phase soot formation have been considered. The methods have been developed within the constraints on detailed combustion modelling for practical application. Some predictions are assessed by comparison with published experimental data. It is concluded that predictions of the same quality as those of gaseous-fuelled combustors may be obtained neglecting liquid-phase soot formation in case of light fuels.


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