Materials Literature
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The valence band structures of Al–N-codoped [ZnO:(Al, N)] and N-doped (ZnO:N) ZnO films were studied by normal and soft x-ray photoelectron spectroscopy. The valence-band maximum of ZnO:(Al, N) shifts up to Fermi energy level by about 300 meV compared with that of ZnO:N. Such a shift can be attributed to the existence…
Extensive transmission electron microscopy examinations confirm that twinning does occur upon large plastic deformation in nanocrystalline Ni, for which no sign of deformation twinning was found in previous tensile tests. Compelling evidence has been obtained for several twinning mechanisms that operate in nanocrystal…
Optically pumped lasing with low threshold and narrow linewidth was observed in a 4-dicyanomethylene-2-methyl-6-p-dimethylaminostyryl-4H-pyran dye-doped holographic polymer-dispersed liquid crystal transmission grating structure. The results showed that the lasing peak centered at about 609 nm, with a full width at ha…
Combining STM, LEED, and density functional theory, we determine the atomic surface structure of rutile ${\mathrm{TiO}}_{2}$ $(110)\mathrm{\text{\ensuremath{-}}}(1\ifmmode\times\else\texttimes\fi{}2)$: nonstoichiometric ${\mathrm{Ti}}_{2}{\mathrm{O}}_{3}$ stripes along the $[001]$ direction. LEED patterns are sharp an…
The structural and electronic properties of MnxGe1−x alloys (x⩽0.15) fabricated by ion implantation are investigated by means of x-ray diffraction and synchrotron radiation photoemission spectroscopy. The diffraction patterns point to the presence of ferromagnetic Mn5Ge3 nanoparticles; however, valence band spectra, i…
Abstract A relativistic DFT method (ZORA) is used to calculate the 183 W and 17 O NMR chemical shifts for the reduced polyoxotungstates W 5 O 18 W II NO 3– , γ‐SiW 12 O 40 6– , P 2 W 18 O 62 8– , and W 10 O 32 6– with different degrees of (de)localization of the electrons introduced. Despite some discrepancies in the…
A polarization-independent phase modulator using two thin homogeneously stratified but orthogonally oriented liquid crystal (LC) gels is demonstrated. In addition to polarization independence and submillisecond response time, the LC gel possesses a much larger phase change and lower operating voltage than the nanosize…
A direct correlation of structural and optical properties of MOCVD-grown ZnCdO-layers with a systematic variation of Cd-content has been achieved on a microscopic scale using highly spatially and spectrally resolved cathodoluminescence. The ZnCdO layer luminescence measured in cathodoluminescence wavelength images rev…
We have observed that the conductivity of graphene sheets is higher whenever they are loosely bound to the underlying bulk graphite. We also observe that certain edges of the graphene layers show sharp rise in current when biased, indicating enhanced electronic density of states spatially localized near those edges. I…
Abstract A synthetic strategy has been developed for the preparation of new peripheral amine‐ or ammonium‐terminated carbosilane dendrimers of type n G‐[Si(OCH 2 CH 2 NMe 2 ) y ] x or n G‐[Si(OCH 2 CH 2 NMe 3 + I – ) y ] x , respectively. It consists of the alcoholysis of well‐known chlorosilane‐terminated dendrimers…
Detailed impedance analysis of dense nanocrystalline SrTiO3 ceramics in comparison to microcrystalline samples gives direct and unambiguous evidence of a space charge overlap as a characteristic size effect. Owing to the significant extension of depletion zones for the holes, the bulk impedance signal disappears at ab…
A vapor phase transport growth process has been developed to synthesize ZnO quantum dots (QDs) on Si substrates. The characteristics were investigated for as-prepared ZnO QDs without any additional treatment. The formation of ZnO QDs with 6 nm in height and 15 nm in diameter is confirmed by scanning electron microscop…
The deformation mechanism of nanocrystalline Ni (with grain sizes in the range of 30–100 nm) at ultrahigh strain rates (>107s−1) was investigated. A laser-driven compression process was applied to achieve high pressures (20–70 GPa) on nanosecond timescales and thus induce high-strain-rate deformation in the nan…
Optical absorption spectra of small single metal nanoparticles are measured using a far-field technique combining a spatial modulation microscope with a broadband light source. Quantitative determination of the spectral and polarization dependencies of the absorption cross section of individual gold nanoparticles perm…
We present results of a fast-response no-bias-bend (NBB) liquid crystal display, made possible by using a nanostructured alignment layer. Such alignment layers allow high pretilt angles of over 45° to be fabricated reliably. Thus, a stable bend configuration pi-cell can be achieved without applying any bias voltage to…
We observed that, by heating in air, the ZnO nanorods could start to melt at a temperature of ∼750°C, which is greatly reduced comparing with that of the bulk form. Prolonged annealing at this temperature resulted in partial melting of individual nanorods and the coalescence of the nanorods with their neighbors, leadi…
A generalized entropy theory of glass formation is developed by merging the lattice cluster theory for the thermodynamics of semiflexible polymer melts at constant pressure with the Adam-Gibbs relation between the structural relaxation time and the configurational entropy. Since experimental studies have suggested tha…
This work examines a planar cholesteric liquid crystal (CLC) cell with a negative dielectric anisotropy, doped with laser dye, as an electrically tunable one-dimensional photonic crystal laser device. The lasing wavelength is demonstrated to be tunable by applying a voltage. Additionally, lasing can be switched on and…
The plasmon resonance of Au∕SiO2 multilayered nanodisks was studied using light scattering spectroscopy and numerical calculations. Compared to single layered Au nanodisks, multilayered nanodisks exhibit several distinctive properties including significantly enhanced plasmon resonances and tunable resonance wavelength…
We have investigated experimentally the effects of n-type impurities such as Al and H on the magnetic properties of ZnCoO. The carrier density changes slightly upon the introduction of hydrogen but increases significantly in the case of Al. A measurement of magnetic circular dichroism indicates that, of the two impuri…