Temperature Dependence of the Pre-Exponential Factor in the Glow Curve Theory

1979 ◽  
Vol 54 (2) ◽  
pp. K137-K140 ◽  
Author(s):  
M. Balarin
Keyword(s):  
Temperature Dependence ◽  
Glow Curve ◽  
Exponential Factor ◽  
Curve Theory

Self-Diffusion in Isotopically Controlled Heterostructures of Elemental and Compound Semiconductors

1998 ◽  
Vol 527 ◽  
Author(s):  
H. Bracht ◽  
E. E. Haller ◽  
K. Eberl ◽  
M. Cardona ◽  
R. Clark-Phelps
Keyword(s):  
Temperature Dependence ◽  
Diffusion Coefficients ◽  
Secondary Ion Mass Spectrometry ◽  
Activation Enthalpy ◽  
Exponential Factor ◽  
Self Diffusion ◽  
Diffusion Studies ◽  
Exponential Factors ◽  
Secondary Ion ◽  
Diffusion Profiles

ABSTRACTWe report self-diffusion studies of silicon between 855 and 1388°C in highly enriched epitaxial 28Si layers. Diffusion profiles of 30Si and 29Si are determined with high resolution secondary ion mass spectrometry (SIMS). The temperature dependence of the Si self-diffusion coefficients is accurately described with an activation enthalpy of 4.76 eV and a pre-exponential factor of 560 cm2s-1. The single activation enthalpy indicates that Si self-interstitials dominate self-diffusion over the whole temperature range investigated. Self- and interdiffusion in buried Al71GaAs/Al69GaAs/71GaAs isotope heterostructures with different Al composition is measured between 800 and 1160°C. Ga self-diffusion in AlGaAs and interdiffusion of Al and Ga at the AlGaAs/GaAs interface show that Ga diffusion decreases with increasing Al composition and that the interdiffusion coefficient depends linearly on Al concentration. Furthermore Al is found to diffuse more rapidly into GaAs than Ga diffuses in GaAs. The temperature dependence of Ga and Al diffusion in GaAs and of Ga diffusion in AlGaAs is described by a single activation enthalpy in the range of 3.6±0.1 eV, but by different pre-exponential factors. Differences found for Ga and Al diffusion in GaAs and for Ga diffusion in AlGaAs with different Al concentrations are discussed.

About Fe Diffusion in Cu

2012 ◽  
Vol 323-325 ◽  
pp. 171-176 ◽  
Author(s):  
D. Prokoshkina ◽  
A.O. Rodin ◽  
V. Esin
Keyword(s):  
Activation Energy ◽  
Diffusion Coefficient ◽  
Grain Boundary ◽  
Temperature Dependence ◽  
Boundary Diffusion ◽  
Bulk Diffusion ◽  
Grain Boundary Diffusion ◽  
Radiotracer Technique ◽  
Exponential Factor ◽  
Temperature Range

The temperature dependence of the bulk diffusion coefficient of Fe in Cu is determined by EDX in the temperature range from 923 to 1273 K, , m2/s. These results are different from that obtained earlier by radiotracer technique: activation energy is less by 30 kJ/mol and pre-exponential factor is 50 times smaller. Deviations from ideality of investigated solutions do not explain the differences; consequently, the thermodynamical factor would not responsible for such an effect. Fast grain boundary diffusion of Fe in Cu was not observed in the temperature range from 823 to 1073 K.

scholarly journals Glow curve analysis by Gauss-Lorentz function

2013 ◽  
Vol 28 (1) ◽  
pp. 45-51 ◽  
Author(s):  
Zdravko Vejnovic ◽  
Milos Pavlovic ◽  
Marina Kutin ◽  
Milorad Davidovic
Keyword(s):  
Activation Energy ◽  
Kinetic Model ◽  
Kinetic Parameters ◽  
Glow Curve ◽  
Curve Analysis ◽  
Geometric Parameters ◽  
Experimental Curve ◽  
Kinetics Model ◽  
Exponential Factor ◽  
Mixed Order

A new method for fitting glow curves, described in a mixed order kinetics model, with Gauss-Lorentz function is shown. Theoretical expressions of the mixed order kinetics model are shown in a new way, so that the values of kinetic parameters can be obtained through the geometric parameters. When the model is described in this way it is possible to calculate precisely the kinetic parameters such as activation energy, pre-exponential factor and the factor a= n0/(h + n0). At the same time, obtained values of geometric parameters of the experimental curve, which is described with the Gauss-Lorentz function, can be used to estimate the kinetic model, in which thermoluminescence relaxation occurs. This gives a possibility of a new application of Gauss-Lorentz function to be used as a criterion for assessing model of relaxation, when it is not known in advance. The accuracy of fitting is studied, for the specific cases of computer simulated thermoluminescent curves with one peak.

Diffusion of 57Co in amorphous Fe–RE (RE = Dy, Tb, and Ce) and Fe–Si–B alloys

1993 ◽  
Vol 8 (9) ◽  
pp. 2231-2238 ◽  
Author(s):  
Kazumasa Yamada ◽  
Yoshiaki Iijima ◽  
Kazuaki Fukamichi
Keyword(s):  
Activation Energy ◽  
Diffusion Coefficient ◽  
Temperature Dependence ◽  
Tracer Diffusion ◽  
Atomic Size ◽  
Exponential Factor ◽  
Dc Sputtering ◽  
The Matrix ◽  
Diffusion Temperature ◽  
Order Of Magnitude

Tracer diffusion of 57Co in amorphous Fe100−xDyx (x = 20–40), Fe75Tb25, Fe67Ce33, and Fe80Si6B14 alloys prepared by dc sputtering has been studied at temperatures of 523 and 573 K. In the Fe–Dy alloys the diffusion coefficient of 57Co shows a maximum at 33 at.% Dy. The magnitude of the diffusion coefficient of 57Co in Fe75Tb25 is nearly equal to that in Fe75Dy25, while those in Fe67Ce33 and Fe80Si6B14 are about one order of magnitude less than the values in Fe67Dy33 and Fe80Dy20. This suggests that the atomic size of the diffusant and the density of the matrix are dominant in the diffusion. Temperature dependence of the diffusion coefficient D of 57Co in the amorphous Fe75Dy25 alloy has been determined in the range from 493–673 K. It shows a linear Arrhenius relationship expressed by D = 5.7 × 10−2 exp(−199 kJ mol−1/RT) m2 s−1. The magnitudes of the pre-exponential factor and the activation energy suggest that the cobalt tracer atoms in the amorphous Fe75Dy25 alloy diffuse by an interstitial-like mechanism.

Diffusion of Light Hydrocarbons in 5A Zeolite

1973 ◽  
Vol 51 (21) ◽  
pp. 3514-3519 ◽  
Author(s):  
D. M. Ruthven ◽  
R. I. Derrah ◽  
K. F. Loughlin
Keyword(s):  
Temperature Dependence ◽  
Transition State Theory ◽  
State Theory ◽  
Clear Correlation ◽  
Correct Prediction ◽  
Light Hydrocarbons ◽  
Exponential Factor ◽  
5A Zeolite ◽  
Factor Governing ◽  
Sorbate Concentration

Experimental diffusivity data are presented for the diffusion of ethane, ethylene, propane, propylene, cyclopropane, n-butane, 1-butene, cis-2-butene, and trans-2-butene in Linde 5A zeolite. It is shown that the concentration dependence of the diffusivity may be accounted for by considering the non-linearity of the equilibrium isotherms. Activation energies for diffusion, derived from the temperature dependence of the limiting diffusivity at zero sorbate concentration, show a clear correlation with the critical diameters of the sorbate molecules. The data are interpreted in terms of the transition state theory of diffusion and it is shown that, for the simpler molecules, this theory gives a quantitatively correct prediction of the pre-exponential factor governing the temperature dependence of the zeolitic diffusivity.

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