Materials Literature
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We report on a polarization-insensitive liquid crystal (LC) Fresnel lens with the centrosymmetry of dynamic focusing in an orthogonally alternating hybrid configuration. The polarization-insensitive Fresnel lens having such successive orthogonal hybrid alignment in two adjacent zones was fabricated using a single-mask…
Cr 3 + , Eu2+, and Dy3+ codoped Sr4Al14O25 has been synthesized by solid-state reaction. Long persistent phosphorescence in red of Cr3+ and in blue of Eu2+ has been observed in this system with persistence times of over 2h for the red and 10h for the blue. Red phosphorescence is performed through persistent energy tra…
In the framework of a general Landau free energy function, which is used in conventional ferroelectrics, we investigate the ferroelectric and magnetic properties of multiferroic epitaxial BiFeO3 thin films. It is shown that the properties of BiFeO3 thin films, such as lattice parameter, polarization, and magnetization…
The characteristics of an acceptor level in Sb-doped, p-type ZnO were studied using cathodoluminescence (CL) spectroscopy as a function of hole concentration. Variable-temperature CL measurements allowed us to estimate the activation energy of an Sb-related acceptor from temperature-induced decay of CL intensity. The…
Raman measurements have been performed on ZnO bulk materials implanted with 220keV Mn+ ions with various doses from 1015to1017cm2. The results reveal two modes at about 230 and 523cm−1, respectively, which are not observed in unimplanted ZnO. One mode at 230cm−1 is assigned to the acoustic-phonon branch at the zone bo…
We examined the structural and electrical properties of silver sulfide films as a function of the sulfurization time of 70-nm-thick Ag films. Variations in the sulfurization time caused variations in the Ag∕S atomic percentage ratio of the silver sulfide films, and as-grown films with various compositions, such as S-r…
Coplanar waveguide transmission lines have been used to show that the temperature dependent properties of Ba0.5Sr0.5TiO3 thin films used for microwave phase shifters in the frequency range 45MHz–50GHz are correlated strongly with the microstructure of the films. The highest tunability and figure of merit of the phase…
Amorphous films of GeTe, Sb2Te3, and Ge2Sb2Te5 were grown to thicknesses of 0.3–3μm using rf sputtering. The optical properties of these films are influenced by the presence of oxygen impurities. The absorption edge in these glasses is sometimes broader than in “standard” chalcogenide glasses, such as GeSe2 or As2Se3.…
Periodic arrays of Ta nanocolumns, 200nm wide and 600nm tall, were grown by glancing angle sputter deposition onto self-assembled close-packed arrays of 260-nm-diameter silica spheres. Each sphere leads to the development of a single Ta column. As growth progresses, roughening of the column top surfaces causes branchi…
We have investigated visible light diffraction on honeycomb arrays of aligned carbon nanotubes grown on nickel nanoparticles prepared using the nanosphere lithography. A monolayer of 980nm polystyrene spheres was used as the mask for the deposition of nickel nanoparticles from which carbon nanotubes of 100nm in diamet…
We present a detailed strain analysis of epitaxial ferroelectric films taking into account multiple sources of strain, including the lattice mismatch between the film and the substrate, thermal strains due to differences in the thermal expansion coefficients of the film and the substrate, and relaxation by the formati…
The structure and luminescence properties of Mn2+ in CdS nanoparticles are studied. Electron paramagnetic resonance measurements show the existence of three distinct Mn2+ centers with different local structures in CdS nanocrystals: Mn ions substitutionally incorporated on Cd sites [Signal SI: g=2.0025 and a hyperfine…
We have demonstrated surface-enhanced Raman spectroscopy on arrays of Ag nanorods aligned in line by a dynamic oblique deposition technique. For the light polarized along the major axis of the nanorods, the plasma resonance of the Ag nanorods has been tuned to a wavelength suitable for Raman spectroscopy. The average…
A comparative analysis of binary compounds and 61 simple anhydrous salts M(y)(LO(3))(z) (L = S, Se, Te, Cl, Br, I) was performed using the crystallochemical program package TOPOS. A topological similarity was found between the salts and six types of binary compounds (NaCl, NiAs, PoCl(2), Tl(2)S(2), ZnTe, rutile). It i…
Application of very high voltage to atomic force microscope tip leads to the growth of narrow, stringlike domains in some ferroelectrics, a phenomenon that was named “ferroelectric domain breakdown.” In this work the dynamics of domain breakdown have been studied experimentally and theoretically in stoichiometric lith…
The 1∕f noise in individual semiconducting carbon nanotubes (s-CNT) in a field effect transistor configuration has been measured in ultrahigh vacuum and following exposure to air. The amplitude of the normalized current spectral noise density is independent of source-drain current and inversely proportional to gate vo…
Various mechanisms for the growth and renucleation of ultrananocrystalline diamond (UNCD) films are discussed and evaluated in the light of experimental and theoretical evidences in recent publications. We propose that the most likely model for UNCD growth is that where most of the diamond is formed via a similar mech…
A mechanism is described whereby 180° domain wall motion can contribute to the electrically induced strain in a ferroelectric material at subcoercive ac electric fields. The field-dependent, largely reversible motion of ferroelectric, 180° domain walls due to an applied ac electric field is considered. The Rayleigh la…
This letter reports a novel deformation mechanism of twinned Cu nanowires, based on molecular statics and dynamics simulations. Under mechanical loading, Shockley partial dislocations nucleate and glide on a {111} plane toward a twin boundary. Upon penetration of the twin boundary, a dislocation with Burgers vector of…
Solid films of CdSe colloidal quantum dots are conductive when reduced by electrochemistry. The dark conductivity and the photoconductivity of these n-type CdSe nanocrystalline solids have been investigated as a function of film treatment. When the films are treated with NaOH, a carrier mobility of ∼10−2cm2∕Vs and a c…