Self-diffusion of polystyrene in solution 2. Discussion of experimental results on the basis of the reptation mechanism and entanglements

1988 ◽  
Vol 266 (3) ◽  
pp. 208-215 ◽  
Author(s):  
G. Fleischer ◽  
O. E. Zgadzai
Keyword(s):  
Experimental Results ◽  
Self Diffusion

Reduction of Excess Self-Interstitials in Silicon by Germanium and Silicon Implantation-Induced Damage

1989 ◽  
Vol 147 ◽  
Author(s):  
Paul Fahey
Keyword(s):  
Strong Interaction ◽  
Experimental Results ◽  
Self Diffusion ◽  
Implantation Damage ◽  
P Diffusion ◽  
Silicon Implantation

AbstractWe have investigated a phenomena first reported by Pfiester and Griffin, that the presence of implanted Ge in Si can substantially reduce excess self-interstitial concentrations [ J. R. Pfiester and P. B. Griffin, Appl. Phys. Lett., 52, 471 (1988) ]. By studying the effects of Ge implantation on P diffusion, we are able to deduce that residual implantation damage can act as an efficient sink for self-interstitials. This effect can also be produced by Si self-implantation, demonstrating that there is nothing unique about the chemical indentity of Ge in reducing self-interstitial concentrations. Our experiments provide solid evidence that there is no unexpectedly strong interaction of Ge with self-interstitials, a situation that would undermine the validity of previous Ge diffusion experiments aimed at studying Si self-diffusion. Our experimental results show that the effect of Ge implantation on P diffusion is a complicated function of implantation conditions. Diffusion is affected by the order of thl P and Ge implants as well as by changes in implant energies and doses.

Mechanism of Cr Diffusion in GaAs

1991 ◽  
Vol 240 ◽  
Author(s):  
S. Yu ◽  
T. Y. Tan ◽  
U. Gösele
Keyword(s):  
Diffusion Coefficient ◽  
Error Function ◽  
Quantitative Information ◽  
Experimental Results ◽  
Dissociative Mechanism ◽  
Interstitial Diffusion ◽  
Self Diffusion ◽  
Quantitative Basis ◽  
Self Diffusion Coefficient

ABSTRACTDiffusion of substitutional Cr atoms (Crs) in GaAs results from the rapid migration of interstitial Cr atoms (Cri) and their subsequent changeover to occupy Ga sites (or vise versa), a typical substitutional-interstitial diffusion (SID) process. There are two possible ways for the Cri-Crs changeover to occur: the kick-out mechanism in which Ga self-interstitials are involved, and the dissociative mechanism in which Ga vacancies are involved. The Crs indiffusion profiles are of characteristic shapes indicating the dominance of the kick-out mechanism, while the Crs outdiffusion profiles are error-function shaped, indicating the dominance of the dissociative mechanism. In this study, an integrated SID mechanism, which takes into account the effects of both the kick-out and dissociative mechanisms, is used to analyze Cr diffusion results. Going beyond just qualitative consistency, the Cr in- and outdiffusion features in GaAs are explained on a quantitative basis. In this model the kick-out mechanism dominates Cr indiffusion while the dissociative mechanism dominates Cr outdiffusion. Parameters used to fit existing experimental results provided quantitative information on the Ga self-interstitial contribution to the Ga self-diffusion coefficient.

Self-diffusion of polystyrene in solution 1. Experimental results of the NMR pulsed field gradient technique

1988 ◽  
Vol 266 (3) ◽  
pp. 201-207 ◽  
Author(s):  
G. Fleischer ◽  
O. E. Zgadzai ◽  
V. D. Skirda ◽  
A. I. Maklakov
Keyword(s):  
Field Gradient ◽  
Experimental Results ◽  
Pulsed Field ◽  
Self Diffusion ◽  
Gradient Technique

An Apparatus for Non Destructive Study of Atom Transport in Liquids

1970 ◽  
Vol 25 (10) ◽  
pp. 1472-1476 ◽  
Author(s):  
S. Larsson ◽  
L. Broman ◽  
C. Roxbergh ◽  
A. Lodding
Keyword(s):  
Diffusion Coefficients ◽  
Experimental Results ◽  
Self Diffusion ◽  
Present Apparatus ◽  
Non Destructive ◽  
Better Than

Abstract A description is given of a method developed for diffusion and electrotransport measurements in liquids, which permits several successive readings on a sample in uninterrupted anneal. Errors from solidification and sectioning are avoided, and the reproducibility of measured diffusion coefficients is better than two percent. Experimental results are given for gallium self-diffusion. The present apparatus can be conveniently applied to many liquids solidifying below some 280 °C utilizing gamma tracers with energies in the range 0.2 - 2.0 MeV. The design can be modified for higher temperatures.

EXCHANGE BETWEEN METALS AND THEIR IONS IN SOLUTION

1959 ◽  
Vol 37 (1) ◽  
pp. 205-212 ◽  
Author(s):  
Cecil V. King ◽  
Nancy E. McKinney
Keyword(s):  
Experimental Results ◽  
Exchange Current ◽  
Internal Diffusion ◽  
Tracer Method ◽  
Self Diffusion ◽  
Metal Specimen ◽  
Tracer Solution ◽  
Local Cell

The mechanisms by which a metal specimen can acquire radioactivity when immersed in a tracer solution of its own ions are discussed. Consideration is given to the roles of exchange current, adsorption, local cell electrolysis, corrosion, and self-diffusion within the metal. It is shown that exchange current cannot be measured by the tracer method unless conditions are unusually favorable, and that too little attention has been paid to the role of internal diffusion. Some experimental results with silver are presented and the importance of internal diffusion is shown.

Gold Diffusion in Silicon During Gettering by an Aluminum Layer

1997 ◽  
Vol 490 ◽  
Author(s):  
Subhash M. Joshi ◽  
Ulrich M. Gösele ◽  
Teh Y. Tan
Keyword(s):  
Surface Region ◽  
Experimental Results ◽  
Wafer Surface ◽  
Aluminum Layer ◽  
Self Diffusion ◽  
Diffusion Parameters ◽  
Model Predictions ◽  
Gold Diffusion ◽  
Si Wafer

ABSTRACTPrevious modeling of Al gettering of Au in Si indicated that, for an Al gettering layer placed on one surface of a Si wafer, Au will be gettered from both surface regions of the wafer to progressively greater depths with time. This is because, in Si, Au is a substitutional-interstitial (Aus-Aui) species with its diffusion governed by the kick-out mechanism which is mediated by Si self-inter-stitials (I). During gettering by the Al-Si liquid at one wafer surface, Aus atoms change over to Au atoms to rapidly migrate out of Si into the liquid. The changeover process consumes I. At the two wafer surface regions, the consumed I will be quickly replenished, while in the wafer interior an I undersaturation develops which hinders the Aus-Aui changeover and hence the gettering process. Experimental evidences which confirm the predictions have been obtained. Au was indiffused into a FZ Si wafer at 950°C for 16 hr. After removing the Au source and etching, samples from the in-diffused wafer were annealed at 1000°C without or with an Al layer on one surface. For samples without Al, there is no change in the net Au content, while the U-shaped indiffused profile becomes flatter. For samples with an Al layer, both wafer surface region Au concentrations were significantly decreased in 30 min while the wafer interior Au concentrations decreased only after annealing for longer times. The model predictions, the experimental results, and the implications on Si self-diffusion parameters will be discussed.

Role of Atomic Size and Valence in Bonding and Diffusion at Metal Surfaces

1992 ◽  
Vol 280 ◽  
Author(s):  
Peter J. Feibelman
Keyword(s):  
Diffusion Barrier ◽  
First Principles ◽  
Metal Surfaces ◽  
Experimental Results ◽  
First Principles Calculations ◽  
Atomic Size ◽  
Self Diffusion ◽  
Chemical Concepts ◽  
And Diffusion

ABSTRACTFirst-principles calculations and corresponding experimental results underline the importance of basic chemical concepts in understanding bonding and diffusion of atoms at and on metal surfaces. Examples discussed include the outward relaxation of clean Be(0001), the separation energies of metal-adatom dimers, concerted substitutional self-diffusion on fcc(001) and (110) surfaces, and adsorption and diffusion barrier sites for adatoms near steps.

Diagnostics of Gold Laser Plasmas

1988 ◽  
Vol 102 ◽  
pp. 357-360
Author(s):  
J.C. Gauthier ◽  
J.P. Geindre ◽  
P. Monier ◽  
C. Chenais-Popovics ◽  
N. Tragin ◽  
...  
Keyword(s):  
Experimental Results ◽  
Pure Gold ◽  
Electronic Temperature ◽  
X Ray ◽  
Laser Plasmas ◽  
Collisional Radiative Model ◽  
Radiative Model

AbstractIn order to achieve a nickel-like X ray laser scheme we need a tool to determine the parameters which characterise the high-Z plasma. The aim of this work is to study gold laser plasmas and to compare experimental results to a collisional-radiative model which describes nickel-like ions. The electronic temperature and density are measured by the emission of an aluminium tracer. They are compared to the predictions of the nickel-like model for pure gold. The results show that the density and temperature can be estimated in a pure gold plasma.

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