Point Defects in Semiconductors: Microscopic Identification, Metastable Properties, Defect Migration, and Diffusion

1989 ◽  
Author(s):  
James A. Van Vechten ◽  
John F. Wager
Keyword(s):  
Point Defects ◽  
Defect Migration ◽  
Microscopic Identification ◽  
Defects In Semiconductors ◽  
And Diffusion

Calculations of the Electronic and Atomic Structure and Diffusion of Point Defects in KNbO3 Perovskite Crystals and Relevant KTN Solid Solutions

2002 ◽  
Vol 718 ◽  
Author(s):  
R. I. Eglitis ◽  
E. A. Kotomin ◽  
G. Borstel
Keyword(s):  
Solid Solutions ◽  
Point Defects ◽  
Large Scale ◽  
Cubic Phase ◽  
Defect Migration ◽  
Scale Modeling ◽  
Indo Calculation ◽  
Large Scale Modeling ◽  
And Diffusion ◽  
Neglect Of Differential Overlap

AbstractIn this paper we review our recent achievements in large scale computer simulations of point defects in advanced perovskite crystals. We have calculated the defect migration energies in the KNbO3 cubic phase using quantum chemical method of the Intermediate Neglect of Differential Overlap (INDO) and classical shell model (SM). The migration energies for the O vacancy obtained by means of these two quite different methods are reasonably close (0.68 eV and 0.79 eV, respectively) and also agree with the only experimental estimate available (ca. 1 eV). Atomic relaxations calculated by these two methods also agree quite well. We used INDO method for a large-scale modeling of the atomic and electronic structure of KNbxTa1-xO3 (KTN) perovskite solid solutions. Results for periodic defect model (large unit cell) of 40 and 320 atoms are compared with 135-atom INDO cluster calculations. Periodic Nb impurities in KTaO3 reveal clear off-center displacement beginning with the smallest calculated concentrations, so does an isolated Nb impurity in a cluster INDO calculation. The magnitude of this displacement is close to the EXAFS observation (0.27 a.u.).

scholarly journals Modeling of the Point Defect Migration across the AlN/GaN Interfaces—Ab Initio Study

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 478
Author(s):  
Roman Hrytsak ◽  
Pawel Kempisty ◽  
Ewa Grzanka ◽  
Michal Leszczynski ◽  
Malgorzata Sznajder
Keyword(s):  
Point Defects ◽  
Density Functional ◽  
Structure Design ◽  
Nitrogen Vacancy ◽  
Energy Bands ◽  
Design Quality ◽  
Functional Theory ◽  
Defect Migration ◽  
Detrimental Impact ◽  
And Diffusion

The formation and diffusion of point defects have a detrimental impact on the functionality of devices in which a high quality AlN/GaN heterointerface is required. The present paper demonstrated the heights of the migration energy barriers of native point defects throughout the AlN/GaN heterointerface, as well as the corresponding profiles of energy bands calculated by means of density functional theory. Both neutral and charged nitrogen, gallium, and aluminium vacancies were studied, as well as their complexes with a substitutional III-group element. Three diffusion mechanisms, that is, the vacancy mediated, direct interstitial, and indirect ones, in bulk AlN and GaN crystals, as well at the AlN/GaN heterointerface, were taken into account. We showed that metal vacancies migrated across the AlN/GaN interface, overcoming a lower potential barrier than that of the nitrogen vacancy. Additionally, we demonstrated the effect of the inversion of the electric field in the presence of charged point defects VGa3− and VAl3− at the AlN/GaN heterointerface, not reported so far. Our findings contributed to the issues of structure design, quality control, and improvement of the interfacial abruptness of the AlN/GaN heterostructures.

scholarly journals Convergence of supercell calculations for point defects in semiconductors: Vacancy in silicon

1998 ◽  
Vol 58 (3) ◽  
pp. 1318-1325 ◽  
Author(s):  
M. J. Puska ◽  
S. Pöykkö ◽  
M. Pesola ◽  
R. M. Nieminen
Keyword(s):  
Point Defects ◽  
Defects In Semiconductors

The Nature and Diffusion of Intrinsic Point Defects in SiC

2002 ◽  
Vol 389-393 ◽  
pp. 471-476 ◽  
Author(s):  
M. Bockstedte ◽  
Matthias Heid ◽  
Alexander Mattausch ◽  
Oleg Pankratov
Keyword(s):  
Point Defects ◽  
Intrinsic Point Defects ◽  
And Diffusion
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