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Atomic Layers (atomic + layer)

Distribution by Scientific Domains
Polymers and Materials Science42%

Terms modified by Atomic Layers

  • atomic layer deposition
    		•
  • atomic layer epitaxy
    		•

    Selected Abstracts

    Interface Atomic-Scale Structure and its Impact on Quantum Electron Transport

    ADVANCED MATERIALS, Issue 48 2009
    Zhongchang Wang
    Local structure, chemistry, and bonding at interfaces often radically affect the properties of materials. A combination of scanning transmission electron microscopy and density functional theory calculations reveals an atomic layer of carbon at a SiC/Ti3SiC2 interface in Ohmic contact to p-type SiC (see image), which results in stronger adhesion, a lowered Schottky barrier, and enhanced transport. This is a key factor to understanding the origin of the Ohmic nature. [source]

    Direct Observation of Multilayer Adsorption on Alumina Grain Boundaries

    JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 3 2007
    Shen J. Dillon
    Grain-boundary films 0.6 nm in size have been observed on the grain boundaries of neodymia (Nd2O3)-doped alumina (,-Al2O3) sintered at 1800°C. Direct observation by high-angle annular dark-field imaging in the aberration-corrected scanning transmission electron microscope shows that this type of grain-boundary structure is the result of multilayer adsorption. Neodymium cations adsorb onto the faces of each of the two grains that comprise the grain boundary by substituting for aluminum cations. The positions of these cations are slightly distorted relative to the perfect lattice, and a third atomic layer in the core of the grain-boundary resides between these two layers. The measurements also confirm that the thickness deduced from high-resolution transmission electron microscopy lattice images are accurate. [source]

    Interface of atomic layer deposited Al2O3 on H-terminated silicon

    PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 9 2006
    K. Y. Gao
    Abstract Al2O3 films 1 to 20 nm thick were deposited as alternative high-, gate dielectric on hydrogen-terminated silicon by Atomic Layer Deposition (ALD) and characterized by Synchrotron X-ray Photoelectron Spec-troscopy (SXPS), Fourier Transform Infrared (FTIR) absorption spectroscopy and admittance measure-ments. The SXPS results indicate that about 60% of the original Si,H surface bonds are preserved at the Al2O3/Si interface and this is confirmed by monitoring the Si,H stretching modes by FTIR spectroscopy in the Attenuated Total Reflection (ATR) mode both before and after ALD of Al2O3. The remaining 40% of Si,H bonds are replaced by Si,O bonds as verified by SXPS. In addition, a fraction of a monolayer of SiO2 forms on top of the Al2O3 dielectric during deposition. The presence of OH-groups at a level of 3% of the total oxygen content was detected throughout the Al2O3 layer through a chemically shifted O 1s component in SXPS. Admittance measurements give a dielectric constant of 9.12, but a relatively high density of interface traps between 1011 and 1012 cm,2 eV,1. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    Molecular dynamics study on effects of surface structures in nanometer scale on energy transfer from fluid to surface

    HEAT TRANSFER - ASIAN RESEARCH (FORMERLY HEAT TRANSFER-JAPANESE RESEARCH), Issue 3 2005
    Masahiko Shibahara
    Abstract Energy transfer from fluid to surface was calculated numerically by using the classical molecular dynamics method in order to investigate the effects of surface structures from 0.1 nm to 10 nm on surface energy transfer. Surface structures on a constant surface area were composed of several hundred atoms having various potential energy parameters, in other words, thermal properties. The upper region in the calculation domain was controlled at a constant temperature and one of the solid atomic layers at the lower region in the calculation domain was controlled at another constant temperature to create a temperature gradient in the calculation system. Energy transfer to the surface was very dependent on surface nanometer scale structures in that affected the static structure and the dynamic behaviors of fluid molecules in the vicinity of the surface. © 2005 Wiley Periodicals, Inc. Heat Trans Asian Res, 34(3): 171,179, 2005; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/htj.20055 [source]

    Structural models for twin interfaces in Pd thin films

    JOURNAL OF MICROSCOPY, Issue 3 2006
    I. TSIAOUSSIS
    Summary In a Pd thin film grown on a 6H-SiC (0001) substrate, several twin interfaces have been observed, classified as (1) {111}, = 3 twin interfaces and (2) {}, = 3 twin interfaces. The first ones are coherent twin interfaces and in some cases exhibit steps of one or more atomic layers in height. The second ones are perpendicular to the first ones. They usually appear with a rigid-body displacement, but in some cases no displacement was observed. Models for the interfaces are proposed. [source]

    Step-Energy Barriers and Particle Shape Changes during Coarsening

    JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 3 2002
    Brian W. Sheldon
    Models of particle shape changes usually do not account for the step-energy barrier associated with adding or removing additional atomic planes from a faceted surface. However, the step-energy barrier can be a substantial limitation when the free energy changes that drive particle shape changes are relatively low. A good example of this is particle coarsening. The analysis presented in this article describes dislocation-free particles with surfaces that have faceted and nonfaceted regions. When the chemical potential differences responsible for shape changes are too small to overcome the step-energy barrier, atomic layers cannot be added or removed from the facets. Even with this constraint, it is possible to add or remove atoms from the particle surface; however, this can cause the particle shape to differ substantially from the traditional equilibrium shape. [source]

    Quasiperiodicity in decagonal phases forced by inclined net planes?

    ACTA CRYSTALLOGRAPHICA SECTION A, Issue 3 2001
    Walter Steurer
    It is generally assumed that decagonal quasicrystals show periodically arranged atomic layers only on net planes perpendicular to the tenfold axis and quasiperiodically arranged ones parallel to it. However, there also do exist only slightly puckered atomic layers that are periodically arranged and inclined to the tenfold axis. They coincide with the net planes of the periodic average structures of the decagonal phase and are related to the strongest Bragg reflections. Since they link quasiperiodic and periodic directions, inclined net planes may play a crucial role for growth and stabilization of decagonal quasicrystals. In fact, it is shown how ideal quasiperiodic long-range order and inflation symmetry allow for the existence of inclined net planes with small corrugation and reinforce the relation with the periodic average structures. [source]