Materials Literature
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Graphitic features are detected on 4H-SiC surface following oxidation and etching using surface enhanced Raman spectroscopy (SERS). The electronic state of the carbon is sp2 on both the Si- and C-faces of 4H-SiC. The structures of the “carbon clusters” consist of two-dimensional graphitic flakes less than 2 nm and one…
Abstract We report for the first time on the electroassisted biomimetic activation of molecular oxygen by a newly prepared electropolymerized polypyrrole‐manganese phthalocyanine film. The prepared films and their intervention in the electroassisted catalytic reduction of molecular oxygen were analyzed by cyclic volta…
Strong temperature-dependent photovoltaic effects have been observed in the heterojunction composed of a La0.32Pr0.35Ca0.33MnO3 (LPCM) film and a 0.5 wt % Nb-doped SrTiO3 substrate. The photovoltage shows a monotonic increase with the decrease of temperature, and its relative change can be as large as ∼7000% for a mod…
Epitaxial Pb(Zr,Ti)O3 (PZT) films 50 and 250nm thick with the Zr∕(Zr+Ti) ratio from 0.13 to 0.65 were grown on (100)cSrRuO3∕∕(100)SrTiO3 substrates at 540°C by pulsed-metalorganic chemical vapor deposition. The crystal orientation, lattice parameter, axial angle, and relative volume fraction of constituent domains wer…
The enzymatic degradation of typical chemically synthesized biodegradable plastics, such as poly(butylene adipate) and poly(epsilon-caprolactone), to a repolymerizable cyclic oligomer under continuous flow using an enzyme column was studied, directed towards green chemical recycling. It was confirmed that both polymer…
We propose ${\mathrm{Si}}_{x}{\mathrm{Ge}}_{1\ensuremath{-}x}$ alloys as suitable candidates for spintronic applications. Remarkably, our first-principles investigation explains, within the local spin density approximation, the microscopic mechanism that stabilizes the half metallicity in Si matrices under Ge alloying…
In order to explore the large shear-strain-induced polymorph, α-Ti3GeC2 polycrystals were investigated by using a synchrotron radiation source to 64GPa under nonhydrostatic state. Upon compression to 26.6GPa, α-Ti3GeC2 starts to transform to β-Ti3GeC2. As compared to α-Ti3GeC2, the cell parameter a of β-Ti3GeC2 is sli…
Na K-edge X ray absorption near-edge structure (XANES) spectra for minerals and glasses were collected using synchrotron radiation. Na-K XANES is a good structural probe to determine the coordination state of this element in important minerals and glasses. From the XANES spectra on crystalline reference phases with di…
We report on the mechanism of photodegradation of porous silicon luminescence in ambient containing molecular oxygen. Energy transfer from excitons confined in silicon nanocrystallites to molecular oxygen results in the generation of highly chemically reactive singlet oxygen molecules. The subsequent interaction of si…
Dual-frequency addressed hybrid-aligned nematic (HAN) liquid crystal cell is demonstrated as a variable optical attenuator at 1.55μm wavelength. By controlling the low- and high-frequency electric field, the dual-frequency liquid crystal (DFLC) molecules can be reoriented parallel or perpendicular to the substrates so…
The performance of a VO2 thin-film microbolometer has been investigated. The device is operated within 35°C<T<60°C, in the hysteretic metal-insulator transition region. An algebraic hysteresis model has been used to model the resistance-temperature characteristic of the sensor. It accurately describes th…
We used a time-of-flight method to study the charge carrier mobility properties of a molecular-aligned discotic liquid crystal semiconductor based on Cu-phthalocyanine. The heated isotropic-phase semiconductor material was sandwiched between transparent electrodes coated onto glass substrates without conventional alig…
A novel process for wrapping individual myoglobin molecules with an ultrathin shell of silica is reported. Confinement of single protein molecules in microemulsion water droplets followed by the controlled hydrolysis and condensation of tetramethoxysilane at the oil/water interface produces discrete protein/ silica na…
The effect of nitride passivation on the visible photoluminescence from nanocrystal Si (nc-Si) is investigated. Silicon-rich silicon nitride (SRSN) and silicon-rich silicon oxide (SRSO), which consist of nc-Si embedded in silicon nitride and silicon oxide, respectively, were prepared by reactive ultrahigh vacuum ion b…
A spherical, disordered, wormhole-like nanocomposite, consisting of 115 nm diameter MCM-41 particles containing 3 nm diameter Pt nanoparticles (see Figure), is described. A surfactant that stabilizes and prevents aggregation of the Pt nanoparticles during synthesis is removed by calcination, resulting in a high Pt cat…
The structural, thermodynamic and optical properties of ${\mathrm{Mg}}_{2}\mathrm{Ni}$ thin films covered with Pd are investigated upon exposure to hydrogen. Similar to bulk, thin films of metallic ${\mathrm{Mg}}_{2}\mathrm{Ni}$ take up 4 hydrogen per formula unit and semiconducting transparent ${\mathrm{Mg}}_{2}\math…
A novel method used to incorporate iron into the three-dimensional mesoporous cubic SBA-1 materials in highly acidic media is presented. The amount of iron present is controlled by simply adjusting the molar hydrochloric acid to silicon ratio. Moreover, the novel catalyst shows significantly higher phenol conversion a…
Robust, stimulus-responsive thin films are prepared by self-assembly of diblock-copolymer micelles from aqueous solution. Atomic force microscopy and fluorescence spectroscopy show that the hydrophobic polymer cores of block copolymer micelles adsorbed at high pH become localized cationic polymer brushes reversibly at…
We report the fabrication and characterization of a biologically sensitive field-effect transistor (Bio-FET) using a nanocrystalline diamond thin film. Biomolecular recognition capability was provided by linking human immunoglobulin G (IgG) to the diamond surface. Electrical measurements reveal behavior characteristic…
Ferromagnetism in Mn-doped GaAs, the prototypical dilute magnetic semiconductor (DMS), has so far been attributed to hole mediated RKKY-type interactions. First-principles calculations reveal a strong direction dependence of the ferromagnetic (FM) stabilization energy for Mn pairs, a dependence that cannot be explaine…