Materials Literature
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The effect of annealing environment on the photoluminescence from silicon nanocrystals synthesized in fused silica by ion implantation and thermal annealing is examined as a function of annealing temperature and time. The choice of annealing environment (Ar, N2, or 5%H2 in N2) is found to affect the shape and intensit…
Two types of gels using dual-frequency liquid crystal are demonstrated. The one using a homogeneous cell shows anisotropic scattering behavior while the other prepared using a cell without polyimide alignment layers exhibits isotropic scattering properties. Both liquid crystal gels are highly transparent in the voltag…
We describe the operation of a silicon optical nanocrystal memory device. The programmed logic state of the device is read optically by the detection of high or low photoluminescence intensity. The suppression of excitonic photoluminescence is attributed to the onset of fast nonradiative Auger recombination in the pre…
We introduce the density functional theory (DFT) local quasicontinuum method: a first principles multiscale material model that embeds DFT unit cells at the subgrid level of a finite element computation. The method can predict the onset of dislocation nucleation in both single crystals and those with inclusions, altho…
Wurtzite-type ZnO tetrapod nanostructures were prepared by evaporating Zn metal under humid argon flow. After the fabrication, Mn was doped into ZnO nanostructures by diffusion at 600°C. The average concentration of Mn was determined to be 8.4mol% by x-ray fluorescence. X-ray diffraction patterns obtained from the dop…
Synthesis of vertically aligned small diameter (single- and double-wall) carbon nanotube films on thermally oxidized n+-Si(001) wafers, with acetylene diluted with ammonia gas mixture using a microwave plasma-assisted chemical vapor deposition technique, is reported. Experiments show that by continuous reduction in th…
In situ electromigration experiments were carried out to study electromigration-induced failure in the upper and lower layers in dual-damascene Cu test structures. The observations revealed electromigration-induced void movement along the Cu/dielectric cap interface. It supports the premise that Cu∕Si3N4 interface act…
A series of liquid crystalline homopolysiloxanes and copolysiloxanes were synthesized. The chemical structures of the monomers M1 –M7 were confirmed by FTIR and 1H NMR spectroscopy. The structure–property relationships of the monomers and polymers are discussed; their phase behaviour and optical properties were invest…
An in-plane switching (IPS) liquid crystal (LC) gel for light shutter is demonstrated. In the voltage-off state, the LC gel is transparent. As the voltage exceeds a threshold, light scattering occurs due to microdomain formations. This light scattering is found to be polarization independent. Such an IPS LC gel is a b…
Abstract Summary: A series of molecular composites of PA 6/PA 66 was synthesized via in situ polymerization. The impact resistance of PA 6 was improved dramatically by incorporating a minor amount of PA 66 (2–10 wt.‐%), without decreasing the tensile strength. Inserting PA 66 macromolecules at a molecular level into a…
We present the derivation of coarse-grained force fields for two types of polymers, polyethylene (PE), and cis-polybutadiene (cis-PB), using the concept of potential of mean force. Coarse-grained force fields were obtained from microscopic simulations for several coarse-graining levels, i.e., different number of monom…
Abstract Summary: Organic‐inorganic hybrid films based on epoxidized cyclohexene derivatized linseed oil (ECLO) and tetraethylorthosilicate (TEOS) oligomers were prepared via a UV‐curing process. The kinetics of the hybrid materials were studied by photo‐differential scanning calorimetry (DSC). In addition to the kine…
We have investigated the characteristic of the dislocations in the ZnO layers grown on c sapphire by the plasma-assisted molecular beam epitaxy under the different Zn∕O flux ratios. The ZnO layers were characterized by the transmission electron microscopy (TEM) and the high-resolution x-ray diffraction (HRXRD). The TE…
Under constant current electromigration, white tin exhibited a resistance drop of up to 10%. It has a body-centered-tetragonal structure, and the resistivity along the a and b axes is 35% smaller than along the c axis. Microstructure evolution under electromigration could be responsible for the resistance drop. Synchr…
We report simultaneous amplified spontaneous emission from two different multiexcitonic transitions −1Se–1S3∕2 and 1Pe–1P3∕2− of colloidal CdSe nanocrystals (NCs) stabilized in high volume fraction in titania matrices. Two-state lasing from both multiexcitonic transitions is achieved in a surface-emitting distributed…
Abstract Summary: An advanced isoconversional method has been applied to determine the effective activation energies ( E ) for the glass transition in polystyrene (PS), poly(ethylene terephthalate) (PET), and boron oxide (B 2 O 3 ). The values of E decrease from 280 to 120 kJ · mol −1 in PS, from 1 270 to 550 kJ mol −…
The relationship of the microstructure of supercooled, highly viscous glycerol to the temperature dependence of its density, thermal expansion coefficient, and shear viscosity are discussed. The character of this temperature dependence at the transition from low viscosity state to the solid amorphous state (solidified…
The synthesis by hot pressing and wide-band (10Hz–1MHz) magnetoelectric (ME) characterization of bulk composites of nickel zinc ferrite Ni1−xZnxFe2O4 (NZFO) (x=0–0.5) and lead zirconate titanate (PZT) are reported. Hot-pressed samples show an order of magnitude improvement in ME voltage coefficient compared to sintere…
The basic concepts and characteristics of Raman spectra from single-wall carbon nanotubes (SWNTs, both isolated and bundled) are presented. The physical properties of the SWNTs are introduced, followed by the conceptual framework and characteristics of their Raman spectra. Each Raman feature, namely the radial breathi…
A systematic approach to study the phase stability of ${\mathrm{L}\mathrm{i}\mathrm{B}\mathrm{H}}_{4}$ based on ab initio calculations is presented. Three thermodynamically stable phases are identified and a new phase of $Cc$ symmetry is proposed for the first time for a complex hydride. The x-ray diffraction pattern…