Mechanisms of Self-Diffusion and of Doping-Enhancement of Superlattice Disordering in GaAs and AlAs Compounds

1988 ◽  
Vol 144 ◽  
Author(s):  
T.Y. Tan ◽  
U. Gösele
Keyword(s):  
Diffusion Process ◽  
Point Defect ◽  
Group V ◽  
Self Diffusion ◽  
Defect Pair ◽  
Element Diffusion ◽  
N Doping ◽  
Compound Materials ◽  
Positively Charged

ABSTRACTAn understanding of the mechanisms of self-diffusion and of interdiffusion in the compound materials GaAs and AlAs may be arrived at byt noting the effects of (i) charge, (ii) As pressure, and (iii) point defect supersaturation, on the doping enhanced superlattice disordering phenomena. The Ga self-diffusion (and hence Ga-Al interdiffusion) is dominated by the triply-negatively-charged Ga (or Al) vacancy, , under intrinsic and n-doping conditions. Under p-doping, a positively charged Ga self-interstitial , with m not known, contributes to the Ga(AI) diffusion process. Less is known for the group V element diffusion, but the As vacancy (VAs) should be contributing under intrinsic and n-doping conditions while the As selfinterstitial (LAs) may be contributing under p-doping. The contribution of a defect pair may also be involved under p-doping.

Mechanisms of Doping-Enhanced Superlattice Disordering and of Gallium Self-Diffusion in GaAs

1987 ◽  
Vol 104 ◽  
Author(s):  
T. Y. Tan ◽  
U. Gösele ◽  
B. P. R. Marioton
Keyword(s):  
Fermi Level ◽  
Point Defect ◽  
Dopant Diffusion ◽  
Self Diffusion ◽  
N Doping ◽  
Charged Point Defect ◽  
Charged Point ◽  
Defect Species ◽  
Level Effect ◽  
Positively Charged

ABSTRACTRecently available Ga-Al interdiffusion results in GaAs/AlAs superlattices allow to conclude that Ga self-diffusion in GaAs is carried by triply-negatively charged Ga vacancies under intrinsic and n-doping conditions. The mechanism of the Si enhanced superlattice disordering is the Fermi-level effect which increases the concentrations of the charged point defect species. For the effect of the p-dopants Be and Zn, the Fermi-level effect has to be considered together with dopant diffusion induced Ga self-interstitial supersaturation or undersaturation. Self-diffusion of Ga in GaAs under heavy p-doping conditions is governed by positively charged Ga self-interstitials.

Thermal Equilibrium Concentrations and Effects of Ga Vacancies in n-TYPE GaAs

1993 ◽  
Vol 300 ◽  
Author(s):  
Teh Y. Tan ◽  
Homg-Ming You ◽  
Ulrich M. Gösele
Keyword(s):  
Temperature Dependence ◽  
Point Defect ◽  
Thermal Equilibrium ◽  
Quantitative Data ◽  
Equilibrium Concentration ◽  
Negative Temperature ◽  
Positive Temperature ◽  
Self Diffusion ◽  
N Doping ◽  
Equilibrium Concentrations

ABSTRACTWe have calculated the thermal equilibrium concentrations of the various Ga vacancy species in GaAs. That of the triply-negatively-charged Ga vacancy, V3Ga has been emphasized, since it dominates Ga self-diffusion and Ga-Al interdiffusion under intrinsic and ndoping conditions, as well as the diffusion of Si donor atoms occupying Ga sites. Under strong n-doping conditions, the thermal equilibrium V3Ga concentration, CeqvGa.3−(n), has been found to exhibit a temperature independence or a negative temperature dependence, in the sense that the CeqvGa.3−(n) value is either unchanged or increases as the temperature is lowered. This is contrary to the normal positive temperature dependence of point defect theerqmal equilibrium concentrations, which decreases as the temperature is lowered. This CeqvGa.3−(n) property provides explanations to a number of outstanding experimental results, either requiring the interpretation thatV3−Ga has attained its thermal equilibrium concentration at the onset of each experiment, or requiring mechanisms involving point defect non-equilibrium phenomena. Furthermore, there exist also a few quantitative data which are in agreement with the presently calculated results.

Improved (BH)max and Squareness in Diffusion-processed Hot-deformed Nd-Fe-B Magnets by Self-diffusion Process Under Pressure

2021 ◽  
pp. 163051
Author(s):  
Xianshuang Xia ◽  
Tieqiao Zhang ◽  
Mei Liu ◽  
Lanting Zhang ◽  
Renjie Chen ◽  
...  
Keyword(s):  
Diffusion Process ◽  
Self Diffusion

Dopants in Hgcdte

1997 ◽  
Vol 487 ◽  
Author(s):  
M. A. Berding ◽  
A. Sher
Keyword(s):  
Ab Initio ◽  
Point Defect ◽  
Experimental Finding ◽  
Large Fraction ◽  
Fast Diffusion ◽  
Microscopic Mechanism ◽  
Group V ◽  
Native Point Defect ◽  
Group I ◽  
Bond Strengths

AbstractIn this paper we discuss our ab initio calculations of native point defect and impurity densities in HgCdTe. Our calculations have explained the experimental finding in general, and in particular have explained the in-active incorporation of the group VII elements under mercury-deficient conditions; have shown that the group I elements have a large fraction of interstitial incorporation, thereby explaining their fast diffusion; and have described a microscopic mechanism for the amphoteric behavior of the group V elements. We discuss the trends found among the compounds in terms of the underlying bond strengths to understand why the various elements behave the way they do.

On the linearity of the self-diffusion process

1982 ◽  
Vol 27 (1) ◽  
pp. 37-56 ◽  
Author(s):  
William W. Wood ◽  
Jerome J. Erpenbeck
Keyword(s):  
Diffusion Process ◽  
The Self ◽  
Self Diffusion

Self-Diffusion Process in an FCC Crystal Caused by the Passage of a Shock Wave

2015 ◽  
Vol 58 (6) ◽  
pp. 828-832 ◽  
Author(s):  
A. V. Markidonov ◽  
M. D. Starostenkov ◽  
M. V. Smirnova
Keyword(s):  
Shock Wave ◽  
Diffusion Process ◽  
Self Diffusion

From the Mystery to the Understanding of the Self-Interstitials in Silicon

1980 ◽  
Vol 2 ◽  
Author(s):  
W. Frank ◽  
A. Seeger ◽  
U. Gösele
Keyword(s):  
High Temperature ◽  
The Self ◽  
Experimental Conditions ◽  
Group V ◽  
Group Iii ◽  
Enhanced Diffusion ◽  
Self Diffusion ◽  
Thermally Activated ◽  
Temperature Equilibrium ◽  
K Concentration

ABSTRACTOur present knowledge on self-interstitials in silicon and the rôle these defects play under widely different experimental conditions are surveyed. In particular, the following phenomena involving self-interstitials either in supersaturations or under high-temperature thermal-equilibrium conditions are considered: mobility-enhanced diffusion of self-interstitials below liquid-helium temperature, thermally activated diffusion of self-interstitials at inter-mediate temperatures (14O K to 600 K), concentration-enhanced diffusion of Group-III or Group-V elements in silicon at higher temperatures, and— as examples for high-temperature equilibrium phenomena — self-diffusion and diffusion of gold in silicon. This leads to the picture that the self-interstitials in silicon may occur in different electrical charge states and possess dumbbell configurations or are extended over several atomic volumes at intermediate or high temperatures, respectively.

Modeling of TED Point Defect Paramater Extraction

2002 ◽  
Vol 717 ◽  
Author(s):  
Heidi Meyer ◽  
Scott T. Dunham
Keyword(s):  
Point Defect ◽  
Diffusion Capacity ◽  
Enhanced Diffusion ◽  
Self Diffusion ◽  
Transient Enhanced Diffusion ◽  
Two Factors

AbstractThe work investigates simple transient enhanced diffusion (TED) behavior, which is a reflection of the interstitial behavior in the system. The analysis shows that TED depends mainly on two factors: the intial demage profiles and the DICI product. We find that, based on these two inputs, the extent of TED can be accurately diffusion capacity (DICI) which is compared to values previously extracted from diffcusion and silicon self-diffusion experiments.

CALCULATIONS OF SELF-DIFFUSION PROCESS AND COEFFICIENT IN ORDERED B2 AlCo

2013 ◽  
Vol 27 (19) ◽  
pp. 1341034
Author(s):  
ZHI-SHENG NONG ◽  
JING-CHUAN ZHU ◽  
YONG CAO ◽  
XIA-WEI YANG ◽  
ZHONG-HONG LAI ◽  
...  
Keyword(s):  
Diffusion Process ◽  
First Principles ◽  
Diffusion Coefficients ◽  
Density Functional ◽  
Nearest Neighbor ◽  
The Self ◽  
First Principles Calculations ◽  
Self Diffusion ◽  
Diffusion Mechanisms ◽  
Semi Empirical

The self-diffusion process in B2 type intermetallic compound AlCo has been investigated by the first-principles calculations within the frame work of density functional theory (DFT). The obtained mono-vacancy formation, migration and activation energies for four self-diffusion mechanisms, the next-nearest-neighbor (NNN) jump, [110] six-jump cycle (6JC), straight [100] 6JC and bent [100] 6JC diffusion show that the NNN jump mechanism of Co vacancy requires the lowest activation energy (Q = 6.835 eV ) in these diffusion mechanisms, which indicates that it is the main way of self-diffusion in AlCo . The electronic structure including the electron density difference on (-1 1 0) plane as well as atomic Mulliken populations were calculated, and the change of bonding behavior during the [110] 6JC process was discussed in detail. Finally, the self-diffusion coefficients of NNN jump and 6JC mechanisms for AlCo were also studied via the first-principles calculations and semi-empirical predictions, which indicates that the self-diffusion coefficients for NNN jump of Co vacancy show the highest value than the others.

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