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Range Order (range + order)

Distribution by Scientific Domains
Physics and Astronomy55%
Polymers and Materials Science33%

Kinds of Range Order

  • long range order
    		•
  • short range order
    		•

    Selected Abstracts

    Silver Nanoparticles with Controlled Dispersity and Their Assembly into Superstructures

    ADVANCED ENGINEERING MATERIALS, Issue 5 2010
    Karsten Moh
    In this paper we report on the influence of particle size distribution, particle substrate interaction, and drying behavior on the self-assembly process using ligand stabilized silver particles. Two-dimensional particle arrays were characterized using transmission electron microscopy and extensive image analysis. The formation of such structures was observed in situ using an environmental scanning electron microscope in WET-STEM mode. The results confirm that a small particle size distribution is crucial for the formation of regular particle patterns with long range order, but also the particle substrate interaction and the particle density have an influence on the degree of ordering. Additionally, we find that separated binary particle assemblies keep the orientation of their two-dimensional hexagonal lattices over alternating domains of small and big particles. This is probably enabled due to the formation of dislocations and a small change of the course of the lattice lines within the respective boundary. [source]

    Atom Probe Tomography II.

    ADVANCED ENGINEERING MATERIALS, Issue 12 2006
    The Precipitation in Al Base Alloys
    Abstract This paper presents two illustrations of the study of phase separation in Al-based alloys by means of tomographic atom probe. In an AlMgSi alloy, calculations of pair correlation functions have revealed that the nature of solute short range order differs from a pre-aged specimen to a non-pre-aged specimen. This results in different responses to aged hardening treatments. Concerning Al3(Zr,Sc)-type dispersoids observed in another Al-based alloy, they are found to display a core-shell structure wherein Zr is mainly present in the dispersoids periphery. This duplex structure is likely to explain the relative stability of Al3(Zr,Sc) dispersoids. [source]

    Identification of Nucleation Center Sites in Thermally Annealed Hydrogenated Amorphous Silicon

    ADVANCED FUNCTIONAL MATERIALS, Issue 14 2009
    A. Harv Mahan
    Abstract Utilizing the concepts of a critical crystallite size and local film inhomogeneity, it is shown that nucleation in thermally annealed hydrogenated amorphous silicon occurs in the more well ordered spatial regions in the network, which are defined by the initial inhomogeneous H distributions in the as-grown films. Although the film H evolves very early during annealing, the local film order is largely retained in the still amorphous films even after the vast majority of the H is evolved, and the more well ordered regions which are the nucleation center sites for crystallization are those spatial regions which do not initially contain clustered H, as probed by H NMR spectroscopy. The sizes of these better ordered regions relative to a critical crystallite size determine the film incubation times (the time before the onset of crystallization). Changes in film short range order upon H evolution, and the presence of microvoid type structures in the as grown films play no role in the crystallization process. While the creation of dangling bonds upon H evolution may play a role in the actual phase transformation itself, the film defect densities measured just prior to the onset of crystallization exhibit no trends which can be correlated with the film incubation times. [source]

    Determination of the local structure of the first and second shells in ordered and disordered Ni,Mn alloys

    JOURNAL OF SYNCHROTRON RADIATION, Issue 2 2001
    A. V. Ryazhkin
    The coordination numbers and the interatomic distances for 50, 75 and 80 at.% Ni-Mn alloys in ordered and disordered states are presented. A new method for determining the first and second nearest neighbor coordination numbers in a binary alloy is applied. It is shown that magnetic properties of these alloys depend on short range order in atomic arrangement. [source]

    Structural order on different length scales in amorphous silicon investigated by Raman spectroscopy

    PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 3 2010
    S. Muthmann
    Abstract Parameters for the structural short (SRO) and medium range order (MRO) of hydrogenated amorphous silicon (a-Si:H) films on the edge of the microcrystalline silicon (µc-Si:H) phase transition were studied with Raman spectroscopy. The observed samples were deposited using radio frequency plasma enhanced chemical vapor deposition. The studied films were grown with various constant and non-constant silane concentrations (SCs). A substrate dependent correlation of SC to the intensity ratio (IMRO) of the transversal acoustical (TA) and the transversal optical (TO) phonon bands was found. A strong correlation between width and position of the (TO) phonon band was observed. These two easily accessible parameters show an increase of SRO when IMRO decreases. [source]

    Optical properties of thick metal nanohole arrays fabricated by electron-beam and nanosphere lithography

    PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 5 2009
    Ahmad Reza Hajiaboli
    Abstract Optically thick metallic nanohole structures were fabricated using two different methods , electron-beam and nanosphere lithography. The nanosphere lithography technique was based on self-assembling of polystyrene or silica nanospheres (0.560,1.25 ,m in diameter) followed by the deposition of a silver film. The holes size and periodicity of the patterns as well as optical properties (transmission and reflection in the Visible,NIR) of the structures were investigated. The extraordinary optical transmission (EOT) was studied experimentally in both structures and it was found to be dependent on the geometrical parameters (holes shape, diameter and periodicity of structures). As the samples were made for long range order, the effect of the defects like missing holes, change of periodicity or variation of the holes shape, were also studied. The experimental results, especially the position of the SPR band in the different nanohole structures, were compared with those found by simulation carried out with 3D FDTD (finite difference time domain). (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    Single crystalline 2D porous arrays obtained by self organization in n-InP

    PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 1 2003
    S. Langa
    Abstract Self organization is a rather common phenomenon during pore formation in III,V semiconductors. The so called tetrahedron-like pores, the domains of crystallographically oriented pores in n-GaAs, or the macroscopic voltage oscillations in n-InP at high constant current densities are examples of a self organization process. In this paper we will discuss two-dimensional arrays of pores in n-InP with the unique property that they may form a single crystal as a result of a self organization process. The reasons for this long range order and its dependence on the etching conditions will be discussed. [source]

    Dynamical T-matrix theory for high-density excitons in coupled quantum wells

    PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 10 2006
    R. Zimmermann
    Abstract Excitons in coupled quantum wells open the possibility to reach high densities close to equilibrium. In a recent experiment employing a lateral trap potential, a blue shift and a broadening of the exciton emission line has been seen [D. W. Snoke et al., Solid State Commun. 134, 37 (2005)]. The standard Hartree,Fock treatment can explain the blue shift but fails to give a finite broadening. Starting from the (spin-dependent) many-exciton Hamiltonian with direct and exchange potential, we present a dynamical T-matrix calculation for the single-exciton Green's function which is directly related to the frequency- and angle-resolved photoluminescence. The calculated spectrum is blue shifted and broadened due to exciton,exciton scattering. At high excitation, both the spectrum and the angular emission are getting narrow. This is a direct manifestation for off-diagonal long range order and a precursor of condensation. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    Dependence of transport properties in tunnel junction on boron doping

    PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 3-4 2010
    M. J. Shi
    Abstract Boron-doped hydrogenated silicon films with different gaseous doping ratio (B2H6/SiH4) were fabricated as recombination p layers in tunnel junctions. The measurements of I-V characteristics of the junctions and transparency spectra of p layer indicated that the best gaseous doping ratio of the recombination layer is 0.04, which is correlated to the degradation of short range order (SRO) in the inserted p thin film. The junction with such recombination layer has small resistance, near ohmic contact. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]