Papers by Keyword: Defect

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Authors: Christoph Seitz, Z.G. Herro, Boris M. Epelbaum, Albrecht Winnacker, Rainer Hock, Andreas Magerl
Abstract: A structural characterisation of the first [01-15] grown 6H SiC crystals is presented. They show a different micro domain structure outside the facetted region as compared to conventionally [0001] grown crystals. It is imposed by the reduced rotational symmetry for this direction which favours the activation of a low number of glide systems.
Authors: Zhe Liu
Abstract: Aiming at many problems of existing feature model of fabric defects detection, such as large calculation, not exact expression and not extensive defects categories, a new ‘super fuzzy’ feature is proposed in this paper. This new method can solve above problems. Firstly, a general model of ‘super fuzzy’ is given. Some cent-characteristics denoted different kinds of defects are combined according to weight factor, and each cent-characteristic is guaranteed in a same quantity grade by modified constant vector. Then, a concrete ‘super fuzzy’ feature model combined by four cent-characteristics for fabric materials is obtained, and this model is optimized. Finally, after some programs experiments, concrete effect of fabric materials defects denoted by ‘super fuzzy’ feature is validated. Results show that ‘super fuzzy’ algorithm is effective for fabrics defects detection with different texture considering fabric characteristics, and defects feature of many fabrics is expressed quickly and exactly with no pre-supervised learning.
Authors: Qing Bo Wang, Cui Zhou
Abstract: We researched the effect of single intrinsic defect of the structure and electronic properties of V-doped ZnO. After vanadium (V) atom replaced one zinc atom, lattice constants and bulk modulus increased slightly 1.2% and as high as 8.9%, respectively. The total energy showed that oxygen defect inclined to stay at a position far from V atom but zinc defect likely to localize at a position near V atom. The electronic density state of pure ZnO was semiconductor behavior. Vanadium doping introduced a spin-polarization around Fermi-level. The 3d orbital of V split into triplet-state ta (antibonding state), dual-state e (nonbonding state) and triplet-state tb (bonding state) in the wurtzite ZnO crystal field. The ta state hybridized with O2p state above Fermi-level, which made Zn15VO16 underwent a semiconductor-halfmetal transition. Vanadium substitution moved the electronic density states to lower energy. Oxygen defect had little effects on V-doped ZnO while zinc defect moved the density of states to higher energy. Our paper provided a reference for the preparation and application of V-doped ZnO.
Authors: Emmanuel Igumbor, Ezekiel Omotoso, Walter Ernst Meyer
Abstract: We present results of defect formation energies and charge state thermodynamic transition levels of Mg and Te interstitials in MgTe wurzite structure. We use the generalized gradient approximation and local density approximation functionals in the framework of density functional theory for all calculations. The formation energies of the Mg and Te interstitials in MgTe for both the tetrahedral and hexagonal configurations were obtained. The Mg and Te interstitials in MgTe depending on the functional, introduced transition state levels that are either donor or acceptor within the band gap of the MgTe. The Te interstitial exhibit charge states controlled metastability, negative-U and DX centre properties. The Mg interstitial acts as deep or shallow donor and there is no evidence of acceptor levels found for the Mg interstitial.
Authors: R.T. Leonard, Y. Khlebnikov, Adrian R. Powell, C. Basceri, M.F. Brady, I. Khlebnikov, Jason R. Jenny, D.P. Malta, Michael J. Paisley, Valeri F. Tsvetkov, R. Zilli, E. Deyneka, H.McD. Hobgood, Vijay Balakrishna, Calvin H. Carter Jr.
Abstract: Recent advances in PVT c-axis growth process have shown a path for eliminating micropipes in 4HN-SiC, leading to the demonstration of zero micropipe density 100 mm 4HN-SiC wafers. Combined techniques of KOH etching and cross-polarizer inspections were used to confirm the absence of micropipes. Crystal growth studies for 3-inch material with similar processes have demonstrated a 1c screw dislocation median density of 175 cm-2, compared to typical densities of 2x103 to 4x103 cm-2 in current production wafers. These values were obtained through optical scanning analyzer methods and verified by x-ray topography.
Authors: Jean François Michaud, Marc Portail, Thierry Chassagne, Marcin Zielinski, Daniel Alquier
Abstract: The aim of this paper is to review the recent developments conducted by our groups for the achievement of 3C-SiC based heterostructures compatible for MEMS applications. It deals with different aspects, from the influence of the defects generated at the 3C-SiC/Si interface on the mechanical properties to the elaboration of new multilayered structures, required for specific applications like, for example, Atomic Force Microscopy.
Authors: T.E. Schattner, Jeff B. Casady, M.C.D. Smith, Michael S. Mazzola, Vladimir Dmitriev, S.V. Rentakova, Stephen E. Saddow
Authors: Evgenia V. Kalinina, Nikita B. Strokan, Alexander M. Ivanov, A. Sadohin, A. Azarov, V. Kossov, R. Yafaev, S. Lashaev
Abstract: The detector structures based on Al ion-implanted p+-n junctions in 4H-SiC have been manufactured and tested at temperatures up to 170oC by α-particles with energies of 3.9 and 5.5 MeV. Structural peculiarities of thin Al high dose ion implanted layers before and after short high temperature activation annealing were studied by combination of Rutherford back scattering/channeling spectrometry and cross-sectional transmission electron microscopy. The detector structures fabricated on this thin ion implanted p+-n junctions operated in the temperature range of 16-170 oC with reproducible stable spectrometric characteristics. The charge collection efficiency and the energy resolution of detectors improved with rising temperature up to 170 oC, that was obtained in SiC detectors for the first time.
Authors: Matthias Stockmeier, Rainer Hock, Octavian Filip, Boris M. Epelbaum, Albrecht Winnacker, Andreas Magerl
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