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3 results on '"trapping properties"'

1. Simulation Study of the Trapping Properties of HfO2 -Based Charge-Trap Memory Cells.

Author

Driussi, Francesco, Spiga, Sabina, Lamperti, Alessio, Congedo, Gabriele, and Gambi, Alberto

Subjects
*ELECTRON traps, *ELECTRIC cells, *HAFNIUM oxide, *FLASH memory, *MATERIALS, *MICROFABRICATION, *LOGIC circuits
Abstract

In this paper, the trapping properties of HfO2 -based charge-trap cells have been extensively studied by means of a synergic use of material analysis, electrical characterization, and electrical and atomistic modeling. We assessed the impact of process conditions [i.e., postdeposition annealing (PDA)] on the material structure and the trapping behavior of the fabricated gate-stacks. Furthermore, we present reliable models for the HfO2 structure and for the defects responsible for the electron trapping. We found that HfO2 has a trap density comparable with that of SiN that depends on the PDA temperature. The HfO2 traps are shallower in energy than SiN traps, but retention of memory cells is still sufficient, also because of a slightly larger electron affinity and a larger permittivity than SiN that allows thicker layers while preserving the equivalent oxide thickness of the gate-stack. [ABSTRACT FROM AUTHOR]

Published
2014
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2. Synthesis and properties of a series of β-cyclodextrin/nitrone spin traps for improved superoxide detection

Author

Patrick Bernasconi, Egon Rizzato, Antal Rockenbauer, Didier Siri, Anouk Gaudel-Siri, Olivier Ouari, Roselyne Rosas, Stéphane Viel, Hakim Karoui, Micael Hardy, Laszlo Jicsinszky, David Bardelang, Florent Poulhès, Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Spectropôle - Aix Marseille Université (AMU SPEC), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Cyclolab recherche et développement, PO Box 435, H-1525 Budapest, Hongrie, Institute of Materials and Environmental Chemistry [Budapest], Research Centre for Natural Sciences, Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), Laboratoire Chimie Provence (LCP), Université de Provence - Aix-Marseille 1-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université de Provence - Aix-Marseille 1-Institut de Chimie du CNRS (INC), and Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)

Subjects
Nitroxide mediated radical polymerization, Molecular Conformation, Ascorbic Acid, Chemistry Techniques, Synthetic, Molecular Dynamics Simulation, 010402 general chemistry, Photochemistry, 01 natural sciences, Biochemistry, in-vivo, cyclic nitrone, Adduct, Nitrone, law.invention, metabolic stability, chemistry.chemical_compound, conjugate, law, Limit of Detection, Superoxides, Moiety, [CHIM]Chemical Sciences, Physical and Theoretical Chemistry, epr, Electron paramagnetic resonance, Alkyl, chemistry.chemical_classification, Cyclodextrin, radical adducts, 010405 organic chemistry, Chemistry, Superoxide, Organic Chemistry, beta-Cyclodextrins, Electron Spin Resonance Spectroscopy, Glutathione, 0104 chemical sciences, Kinetics, inclusion, trapping properties, resonance, depmpo, Nitrogen Oxides, Spin Labels
Abstract

International audience; Three new DEPMPO-based spin traps have been designed and synthesized for improved superoxide detection, each carrying a cyclodextrin (CD) moiety but with a different alkyl chain on the phosphorus atom or with a long spacer arm. EPR spectroscopy allowed us to estimate the half-life of the superoxide spin adducts which is close to the value previously reported for CD-DEPMPO (t(1/2) approximate to 50-55 min under the conditions investigated). The spectra are typical of superoxide adducts (almost no features of the HO center dot adduct that usually forms with time for other nitrone spin traps such as DMPO) and we show that at 250 mu M, the new spin trap enables the reliable detection of superoxide by 1 scan at the position opposite to the corresponding spin trap without the CD moiety. The resistance of the spin adducts to a reduction process has been evaluated, and the superoxide spin adducts are sensitive to ascorbate and glutathione (GSH), but not to glutathione peroxidase/GSH, reflecting the exposed nature of the nitroxide moiety to the bulk solvent. To understand these results, 2D-ROESY NMR studies and molecular dynamics pointed to a shallow or surface self-inclusion of the nitrone spin traps and of nitroxide spin adducts presumably due to the high flexibility of the permethyl-beta-CD rim.

Published
2017

3. Simulation de la cinétique des transitions électroniques entre les niveaux énergétiques d'un semiconducteur doté d'impuretés

Author

G. Kamarinos, J. Brini, and P. Viktorovitch

Subjects
010302 applied physics, Physics, impurity electron states and effects, free electrons, free holes, chemical kinetic reaction equations, semiconductors, 02 engineering and technology, 021001 nanoscience & nanotechnology, impurity density, multiple impurity behaviour, 01 natural sciences, electronic transitions, kinetics simulation, trapping properties, Shockley Read equations, [PHYS.HIST]Physics [physics]/Physics archives, 0103 physical sciences, photoconductivity, carrier capture probability, energy levels, impurity doped semiconductor, 0210 nano-technology, Humanities
Abstract

Nous simulons la cinétique des interactions entre électrons libres, trous libres et impuretés dans un semiconducteur dont l'état stationnaire peut être hors de l'équilibre thermodynamique. L'identité formelle des équations de Shockley-Read avec des équations de cinétique chimique nous permet d'utiliser un calculateur original destiné à simuler des réseaux de réactions chimiques (en neurobiologie par exemple). Nous obtenons la confirmation en régime dynamique de résultats, déduits d'expériences de photoconductivité, concernant les propriétés de piégeage des niveaux d'impuretés. La simulation nous conduit à dégager une méthode permettant de déterminer les caractéristiques des impuretés (niveau énergétique, densité, coefficients d'émission et de captation des électrons et des trous). Nous mettons également en évidence la possibilité de prévoir le comportement de milieux dotés de plusieurs niveaux d'impuretés.

Published
1974

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