Materials Literature
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A judicious choice of the lanthanide cation and its content in the Na 3 (Y 1– a M a )Si 3 O 9 (M=Tm 3+ , Tb 3+ ; a = 0–1) system allows the optical properties to be tuned over a very wide range. The materials have the same framework structure and encompass thulium‐based blue‐ and infrared‐emitters and terbium‐based X‐…
A simple approach to fabricate dendritic conducting polymer networks has been developed by means of electropolymerization of pyrrole onto a micropatterned self‐assembled monolayer. This polypyrrole network was obtained by a combination of microcontact printing (μCP) of an octadecanethiol self‐assembled monolayer (ODT‐…
The temperature-dependent mechanical behavior of passivated copper films is studied. Stresses in copper films of thickness ranging from 40 to 1000 nm, deposited on quartz or silicon substrates and passivated with silicon oxide were measured by using the substrate curvature method. The thermal cycling spans a temperatu…
Etching characteristics of ZnO are investigated by means of inductively coupled plasma (ICP) reactive ion etching in BCl3-based plasmas. Etch rates are studied as a function of BCl3/Cl2/Ar chemistries, substrate temperature, ICP coil power, rf power, and working pressure. Surface profilometer, scanning electron micros…
Ga 2 O 3 –ZnO composite coaxial nanotubes have been fabricated via a simple process combining thermal reaction and physical evaporation. The resulting nanotubes are either empty or partially or completely filled with Ga (see Figure), forming Ga (core)–Ga 2 O 3 (interlayer)–ZnO (outer shell) three‐layer coaxial nanocab…
Abstract Pure copper metal thin films were grown on SiO2/Si(100) substrates by metal–organic (MO) CVD in a horizontal cold‐wall reactor employing the two metal–organic compounds, Cu(OCHMeCH2NR2)2, where R = Et (1) and R = Me (2) as precursors. Thermogravimetric analyses proved them to be convenient compounds for the d…
The ductility of silicon nitride‐based ceramics is dramatically enhanced in the presence of a pulsed electric field/current that induces movement of the charged species present in the grain boundary glassy/liquid phase, and thereby promotes grain sliding along the grain boundaries. The Figure shows an α‐sialon compone…
Polarization holography in photocrosslinkable polymer liquid crystals films is described. By adjusting the polarization modes of the interference light beams, both “pure” polarization and surface relief gratings can be prepared. The Figure shows an optically polarized microscope image of a grating fabricated using ort…
Spatially organized macroporous thin films made of close‐packed nanocrystals (see Figure) can be formed using a single‐step dispersion evaporation technique. Water condensation is induced, in which droplet coalescence is prevented by interfacially active nanocrystals, allowing close‐packed arrays of monodisperse water…
\ensuremath{\gamma}-alumina transforms to \ensuremath{\theta}-alumina and finally to \ensuremath{\alpha}-alumina in the sequence of thermal dehydration of boehmite. We report a detailed theoretical investigation of the \ensuremath{\gamma}- to \ensuremath{\theta}-alumina transformation based on first-principles density…
Lasing that is color‐tunable via application of an electric field has been demonstrated at the edge of the 1D photonic band of a dye‐doped chiral smectic liquid crystal with a periodic spiral structure. The lasing wavelength, which can be shifted by 40 nm using a relatively low electric field, is tuned by the electric…
Photochromic dye (pyrene)–conducting polymer (polypyrrole) core–shell nanomaterials were fabricated using microemulsion micelles as nanoreactors. The adsorption state of pyrene was tunable over a wide range with a small pyrene loading because of the phase separation and the packing constraints of the pyrene crystal. T…
Arrays of 40 nm Bi 2– x Sb x Te 3 nanowires ( x ∼ 0.7, density ∼ 5 × 10 10 cm –2 ) have been synthesized. The individual wires are crystalline, relatively homogeneous, and highly textured in a 〈110〉 direction after thermal treatment. Wires containing Sb exhibit incomplete wetting of the alumina templates in which they…
Charge distributions in the donor layer for the paramagnetic semimetal-like and nonmagnetic insulating phases of the $\ensuremath{\alpha}\ensuremath{-}(\mathrm{B}\mathrm{E}\mathrm{D}\mathrm{T}\ensuremath{-}\mathrm{T}\mathrm{T}\mathrm{F}{)}_{2}{\mathrm{I}}_{3}$ single crystal [BEDT-TTF: bis(ethylenedithiolo)tetrathiafu…
Current-density-functional theory is used to calculate ionization energies of current-carrying atomic states. A perturbative approximation to full current-density-functional theory is implemented for the first time, and found to be numerically feasible. Different parametrizations for the current-dependence of the dens…
We have studied the approach to equilibrium of islands and pores in two dimensions. The two-regime scenario observed when islands evolve according to a set of particular rules, namely relaxation by steps at low temperature and smooth at high temperature, is generalized to a wide class of kinetic models and the two kin…
Recent measurements of the anisotropy of the upper critical field Bc2 on MgB2 single crystals have shown a puzzling strong temperature dependence. Here, we present a calculation of the upper critical field based on a detailed modeling of bandstructure calculations that takes into account both the unusual Fermi surface…
Using a first-principle pseudopotential approach, we have investigated the Schottky barrier heights of abrupt Al/Ge, Al/GaAs, Al/AlAs, and Al/ZnSe (100) junctions, and their dependence on the semiconductor chemical composition and surface termination. A model based on linear-response theory is developed, which provide…
Ni-Mn-Ga is interesting as a prototype of a magnetic shape-memory alloy showing large magnetic-field-induced strains. We present here results for the magnetic ordering of Mn-rich Ni-Mn-Ga alloys based on both experiments and theory. Experimental trends for the composition dependence of the magnetization are measured b…
A novel method for detection of noble-metal nanoparticles by their nonlinear optical properties is presented and applied for specific labeling of cellular organelles. When illuminated by laser light in resonance with their plasmon frequency these nanoparticles generate an enhanced multiphoton signal. This enhanced sig…