From extended defects and interfaces to point defects in three dimensions—The case of InxGa1−xN

2007 ◽  
Vol 401-402 ◽  
pp. 639-645 ◽  
Author(s):  
C. Kisielowski ◽  
T.P. Bartel ◽  
P. Specht ◽  
F.-R. Chen ◽  
T.V. Shubina
Keyword(s):  
Point Defects ◽  
Three Dimensions ◽  
Extended Defects

Microstructural Evolution in Reduced TiO2

1981 ◽  
Vol 39 ◽  
pp. 74-75
Author(s):  
W. T. Donlon ◽  
S. Shinozaki ◽  
E. M. Logothetis ◽  
W. Kaizer
Keyword(s):  
Microstructural Evolution ◽  
Point Defects ◽  
Extended Defects ◽  
Small Deviations ◽  
Controlled Atmospheres ◽  
Limited Solubility ◽  
Thin Foils ◽  
Heat Treated ◽  
Porous Polycrystalline ◽  
Crystallographic Shear

Since point defects have a limited solubility in the rutile (TiO2) lattice, small deviations from stoichiometry are known to produce crystallographic shear (CS) planes which accomodate local variations in composition. The material used in this study was porous polycrystalline TiO2 (60% dense), in the form of 3mm. diameter disks, 1mm thick. Samples were mechanically polished, ion-milled by conventional techniques, and initially examined with the use of a Siemens EM102. The electron transparent thin foils were then heat-treated under controlled atmospheres of CO/CO2 and H2 and reexamined in the same manner.The “as-received” material contained mostly TiO2 grains (∼5μm diameter) which had no extended defects. Several grains however, aid exhibit a structure similar to micro-twinned grains observed in reduced rutile. Lattice fringe images (Fig. 1) of these grains reveal that the adjoining layers are not simply twin related variants of a single TinO2n-1 compound. Rather these layers (100 - 250 Å wide) are alternately comprised of stoichiometric TiO2 (rutile) and reduced TiO2 in the form of Ti8O15, with the Ti8O15 layers on either side of the TiO2 being twin related.

Influence of Growth Rate and C/Si-Ratio on the Formation of Point and Extended Defects in 4H-SiC Homoepitaxial Layers Investigated by DLTS

2009 ◽  
Vol 615-617 ◽  
pp. 393-396 ◽  
Author(s):  
Bernd Zippelius ◽  
Michael Krieger ◽  
Heiko B. Weber ◽  
Gerhard Pensl ◽  
Birgit Kallinger ◽  
...  
Keyword(s):  
Point Defects ◽  
Vapour Deposition ◽  
Electronic Devices ◽  
Pulse Length ◽  
Chemical Vapour ◽  
Extended Defects ◽  
Deposition Method ◽  
Active Point ◽  
Homoepitaxial Layers ◽  
Chemical Vapour Deposition Method

4H-SiC epilayers are homoepitaxially grown on 4H-SiC substrates with different C/Si-ratios and different growth rates by the chemical vapour deposition method. DLTS investigations are applied in order to trace energetically deep states of electrically active point defects and extended defects, which may act as the source for the degradation of electronic devices. In addition, the dependence of the DLTS signal heights on the filling pulse length is studied.

3D Distributions of Chlorine and Sulphur Impurities in a Thin-Film Cadmium Telluride Solar Cell

MRS Advances ◽  
2018 ◽  
Vol 3 (56) ◽  
pp. 3287-3292 ◽  
Author(s):  
Thomas A. M. Fiducia ◽  
Kexue Li ◽  
Amit H. Munshi ◽  
Kurt Barth ◽  
Walajabad S. Sampath ◽  
...  
Keyword(s):  
Cadmium Telluride ◽  
Cadmium Chloride ◽  
High Efficiency ◽  
Cadmium Sulphide ◽  
Diffusion Profile ◽  
Lattice Diffusion ◽  
Three Dimensions ◽  
Device Performance ◽  
Extended Defects ◽  
Cdte Solar Cells

ABSTRACTA cadmium chloride activation treatment is essential for the production of high efficiency cadmium telluride (CdTe) solar cells. However, the effects of the treatment on the distributions of chlorine and sulphur within the device are not fully understood. Here, the detailed locations of chlorine and sulphur in a treated CdTe cell are determined in three dimensions by high resolution dynamic SIMS measurements. Chlorine is found to be present in grain boundaries, grain interiors, extended defects within the grain interiors, at the front interface, and in the cadmium sulphide layer. In each of these regions, the chlorine is likely to have significant effects on local electronic properties of the material, and hence overall device performance. Sulphur is found to have a U-shaped diffusion profile within CdTe grains, indicating a mixed grain boundary and lattice diffusion regime.

Hydrogen Interaction with Point Defects in the Si-SiO2 Structures and its Influence on the Interface Properties

2007 ◽  
Vol 131-133 ◽  
pp. 345-350 ◽  
Author(s):  
Daniel Kropman ◽  
E. Mellikov ◽  
Tiit Kärner ◽  
Ü. Ugaste ◽  
Tony Laas ◽  
...  
Keyword(s):  
Point Defects ◽  
Hydrogen Adsorption ◽  
Impurity Content ◽  
Magnetic Interaction ◽  
Interface Properties ◽  
Extended Defects ◽  
Oxidation Condition ◽  
Paramagnetic Impurities ◽  
Defects And Impurities ◽  
P Type

The type and density of the point defects that are generated in the Si surface layer during thermal oxidation depend on the oxidation condition: temperature, cooling rate, oxidation time, impurity content. Interaction between the point defects with extended defects and impurities affects the SiO2 structure and Si-SiO2 interface properties. Hydrogen adsorption on n- and p- type wafers is different. One possible reason for that can be the strength of the magnetic interaction between the hydrogen and paramagnetic impurities of the adsorbent. The influence of point defects and impurities may be diminished and the interface properties improved by an appropriate choice of the oxidation conditions and postoxidation laser irradiation.

Interaction of Point Defects with Extended Defects in the Si-SiO2 System during its Formation Process

2001 ◽  
Vol 194-199 ◽  
pp. 1737-1744
Author(s):  
Daniel Kropman ◽  
Tiit Kärner ◽  
U. Abru ◽  
M. Strik ◽  
Ü. Ugaste ◽  
...  
Keyword(s):  
Point Defects ◽  
Formation Process ◽  
Extended Defects

Interaction between point defects, extended defects and impurities in the Si–SiO2 system during the process of its formation

2004 ◽  
Vol 459 (1-2) ◽  
pp. 53-57
Author(s):  
D Kropman ◽  
T Kärner ◽  
U Abru ◽  
Ü Ugaste ◽  
E Mellikov
Keyword(s):  
Point Defects ◽  
Extended Defects ◽  
Sio2 System ◽  
Defects And Impurities

A Diffuse Interface Model for Void Formation under Non-Equilibrium Irradiation

2011 ◽  
Vol 1363 ◽  
Author(s):  
Srujan Rokkam ◽  
Anter El-Azab
Keyword(s):  
Point Defects ◽  
Void Formation ◽  
Thermal Fluctuations ◽  
Diffuse Interface ◽  
Cascade Process ◽  
Extended Defects ◽  
Interface Model ◽  
Diffuse Interface Model ◽  
Governing System ◽  
Growth Of Voids

ABSTRACTVoid formation in irradiated materials is an intriguing and technologically important physical process associated with radiation damage. In this communication, we present a diffuse interface model for simulating void formation in materials under irradiation. Voids are treated as aggregates of vacancies left from the cascade damage. The emergence of the void ensembles in the irradiated material is modeled by an Allen-Cahn equation coupled with two Cahn-Hilliard equations governing the space and time evolution of vacancies and interstitials. The governing system of equations includes stochastic generation of point defects representing the cascade process, reaction of vacancies and interstitials, interaction of point defects with extended defects (viz., void surface and grain boundaries) and thermal fluctuations in defects. Numerical simulations demonstrating the model capabilities with respect to nucleation and growth of voids and swelling of the irradiated material are presented.

Ostwald Ripening of {113} Defects Precursors and Transient Enhanced Diffusion

1999 ◽  
Vol 568 ◽  
Author(s):  
Giovanni Manninoo ◽  
Nicholas E.B. Cowem ◽  
Peter A. Stolk ◽  
Fred Roozeboom ◽  
Hendrik G.A. Huizing ◽  
...  
Keyword(s):  
Point Defects ◽  
Ostwald Ripening ◽  
Ion Beam ◽  
Extended Defects ◽  
Defect Band ◽  
Enhanced Diffusion ◽  
Dissociation Energies ◽  
Marker Layer ◽  
High Supersaturation ◽  
Very High

ABSTRACTThe ripening of ion-beam generated point defects into extended defects has been investigated in detail. The interstitial supersaturation has been extracted from boron marker-layer diffusion after annealing under non-equilibrium defect conditions. We measured a very high initial supersaturation followed by a decrease over many orders of magnitude with a characteristic “plateau” related to the presence of {113} defects. A continuum inverse model has been used to properly describe the ripening of point defects into clusters and their evolution in the presence of a remote sink, e.g. the surface. It evidences that a nonconservative Ostwald ripening process takes place inside the defect band during the annealing and sustains the interstitial supersaturation. The model reveals moreover an oscillatory behaviour of dissociation energies of the nanometer-sized defects which are responsible for the initial high supersaturation. These defects are believed to be {113} precursors.

Modeling of Segregation and Microstructural Evolution near Grain Boundary in FE-CR-NI Alloy Under Irradiation

1998 ◽  
Vol 538 ◽  
Author(s):  
N. Sakaguchi ◽  
S. Watanabe ◽  
H. Takahashi
Keyword(s):  
Activation Energy ◽  
Grain Boundary ◽  
Point Defects ◽  
Solute Segregation ◽  
Extended Defects ◽  
Diffusional Process ◽  
Free Zone ◽  
Ni Alloy ◽  
Radiation Induced ◽  
Simultaneous Evolution

AbstractWe have investigated the solute segregation and simultaneous evolution of extended defects in an Fe-Cr-Ni alloy during irradiation by computer simulation. It sheds a light on the accomplishment of performing “the combined total calculation” or “the muliscale modeling” which deals with both radiation-induced segregation and various kinds of internal sink evolution. The formation of dislocation-free zone (DLFZ) was predicted in the vicinity of a grain boundary. It indicated that DLFZ formation is controlled by solute diffusional process via point defects diffusion near the grain boundary and the activation energy obtained by the width of DLFZ corresponds to the half of the value of the radiation-enhanced solute diffusivity.

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