Materials Literature
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Dual-band negative-index metamaterial designs in the near-infrared frequency range are presented and their performance is analyzed using a full-wave numerical electromagnetic scattering method. Negative effective permittivity is provided by a thin layer of metallic film. Negative effective permeabilities are supplied…
We report a structure with 4 thin film layers composed of pure metal and dielectric materials and prepared by sputtering. The reflectance and transmittance are lower than 5% with the absorption to be achieved higher than 95% in the 400-1000nm wavelength region as match to the solar radiance spectrum. The thermal emitt…
Micropatterned growth of ZnO nanorod arrays on silicon substrates using a low temperature aqueous method is demonstrated. ZnO nanocrystals were used as seeds for producing well-aligned, wurtzite ZnO nanorod arrays with spin coating. The shape of the ZnO nanorods was sensitive to the orientation of substrate as well as…
Mn-doped ZnO nanorods are prepared by a chemical vapor deposition method using zinc and MnO2 powders as source materials of Zn and Mn, respectively. Cathodoluminescence (CL) characterization indicates that the Mn-doped ZnO nanorods grown at different growth temperatures have different oxygen vacancy concentrations. Ro…
Abstract Heterojunctions comprising copper thin films and polyimide underlayers are exploited as an important system for generating flexible microelectronic circuit elements. A fully additive‐based chemical method that allows metallization of polyimide films with copper by the in situ reduction of copper ions doped in…
Nanocrystalline diamond microdisks have been fabricated and characterized. The process conditions were chosen to ensure smooth and vertical sidewalls. Focused ion beam milling was used to create ultrasmooth sidewalls. Whispering gallery modes were observed near the nitrogen-vacancy center emission wavelength (637nm) b…
Abstract Raman and infrared spectroscopy enabled insights into the molecular structure of the sampleite group of minerals. These minerals are based upon the incorporation of either phosphate or arsenate with chloride anion into the structure, and as a consequence the spectra reflect the bands attributable to these ani…
A review and analysis is performed of various resonance effects associated with subwavelength one-dimensional (1-D) metal gratings for transverse electric (TE) and transverse magnetic (TM) polarized incident radiation. It is shown that by tuning the structural geometry (especially the groove width) and material compos…
Abstract Hollow Cu nano/microstructures are prepared by reduction of CuSO 4 · 5 H 2 O with glucose by using a mild hydrothermal process. The X‐ray powder diffraction and energy‐dispersive X‐ray analysis indicate that the products are pure Cu and of cubic phase. The morphology of the products can be controlled between…
The authors investigated the field emission from vertically well-aligned zinc oxide (ZnO) nanoneedles grown on the Au∕Ti∕n-Si (100) substrate using metal organic chemical vapor deposition. The turn-on field of ZnO nanoneedles was about 0.85V∕μm at the current density of 0.1μA∕cm2, and the emission current density of 1…
Abstract The microwave‐assisted direct polycondensation of LA to synthesize PLA has been studied. Microwave irradiation strikingly accelerates the polymerization rate of LA compared to conventional heating. By use of a binary catalyst of SnCl 2 / p ‐TsOH, PLA with a $\overline M _{\rm w}$ of 16 000 is obtained within…
Point group theoretical methods are used to determine the electromagnetic properties of metamaterials, based solely upon the symmetries of the underlying constituent particles. From the transformation properties of an electromagnetic (EM) basis under symmetries of the particles, it is possible to determine, (i) the EM…
The authors report the infrared-to-visible frequency upconversion (UPC) process in Er3+ doped PbO–GeO2 glasses containing silver nanoparticles (NPs) with an average diameter of 2.2nm. The absorption spectra of the samples present a band centered at 470nm due to the surface plasmons associated with the NPs. The intensi…
MnAs has been grown by means of MBE on the GaN(0001)-(1x1) surface. Two options of initiating the crystal growth were applied: (a) a regular MBE procedure (manganese and arsenic were delivered simultaneously) and (b) subsequent deposition of manganese and arsenic layers. It was shown that spontaneous formation of MnAs…
The authors discuss a generalized transport model including memory and nonlocal effects, which aims to describe the transition of heat transport from the diffusive regime to the ballistic regime. By using an effective thermal conductivity depending on the Knudsen number, they describe in a single equation the behavior…
Half-metallic ferromagnetic full-Heusler alloys containing Co and Mn, having the formula Co$_2$MnZ where Z a sp element, are among the most studied Heusler alloys due to their stable ferromagnetism and the high Curie temperatures which they present. Using state-of-the-art electronic structure calculations we show that…
Recent experiments showed that the robust charge ordering in manganites can be weakened by reducing the grain size down to nanoscale. Weak ferromagnetism was evidenced in both nanoparticles and nanowires of charge-ordered manganites. To explain these observations, a phenomenological model based on surface phase separa…
We explore an efficient way to numerically evaluate the response of the surface stress of a metal to changes in its superficial charge density by analysis of the strain-dependence of the work function of the uncharged surface. As an application we consider Au(111), (110) and (100) surfaces, employing density functiona…
Ca In 2 O 4 : x Eu 3 + (x=0.5%,1.0%,1.5%) phosphors were prepared by the Pechini sol-gel process [U.S. Patent No. 3,330,697 (1967)] and characterized by x-ray diffraction and photoluminescence and cathodoluminescence spectra as well as lifetimes. Under the excitation of 397nm ultraviolet light and low voltage electron…
High-quality cellulose multifilaments (see figure) are spun using a preliminary pilot apparatus, from the cellulose dope in an NaOH and urea aqueous solution precooled to –12 °C, by using a low-cost, simple, and environmentally friendly process. Small-angle X-ray scattering patterns indicate that the orientation of th…