Materials Literature
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Preserving the structural and functional integrity of interfaces and inhibiting deleterious chemical interactions are critical for realizing devices with sub-50 nm thin films and nanoscale units. Here, we demonstrate that ∼0.7-nm-thick self-assembled monolayers (SAMs) comprising mercapto-propyl-tri-methoxy-silane (MPT…
In this study, a series of nanoindentations was made on NiTi shape memory alloy thin films at millinewton loads with a Berkovich indenter. Mapping of the indentation topography using atomic force microscopy reveals direct evidence that the thermally induced martensitic transformation of these films allows for partial…
We have measured the optical conductivity of single crystal ${\mathrm{L}\mathrm{u}\mathrm{M}\mathrm{n}\mathrm{O}}_{3}$ from 10 to $45\text{ }000\text{ }\text{ }{\mathrm{c}\mathrm{m}}^{\ensuremath{-}1}$ at temperatures between 4 and 300 K. A symmetry allowed on-site Mn $d\mathrm{\text{\ensuremath{-}}}d$ transition near…
The electrical activity of nitrogen as an acceptor in ZnO has been investigated in two ways. First, nitrogen was introduced by means of diallylamine during metalorganic vapor phase epitaxy (MOVPE) yielding incorporation of nitrogen in the range 1016–1021 cm−3. This led to significant compensation of the natural donors…
The atomic processes associated with energy storage and release in irradiated graphite have long been subject to untested speculation. We examine structures and recombination routes for interstitial-vacancy (I-V) pairs in graphite. Interaction results in the formation of a new metastable defect (an intimate I-V pair)…
This letter reports on the pressure dependence of the optical absorption edge of ZnO in the rock-salt phase, up to 20 GPa. Both vapor-phase monocrystals and pulsed-laser-deposition thin films on mica have been investigated. Rock-salt ZnO is shown to be an indirect semiconductor with a band gap of 2.45±0.15 eV, whose p…
Große Hohlräume (10–12.3 nm) werden während der Synthese von mesoporösem kubischem SiO2 durch Blockcopolymer-Template ausgefüllt. Die Größe der Hohlraumeingänge kann zwischen 4 und 9 nm variiert und durch Stickstoffsorption sowie anhand von Goldrepliken ermittelt werden. Diese offenen dreidimensionalen Mesostrukturen…
We report on how the mirror reaction method can be used to prepare silver films with well controlled grain sizes in the range that is known to be ideal for surface plasmon experiments in the visible region of the spectrum. We characterize the morphology of the silver films by atomic force microscopy and their optical…
We report on giant positive magnetoresistance effect observed in VOx thin films, epitaxially grown on SrTiO3 substrate. The MR effect depends strongly on temperature and oxygen content and is anisotropic. At low temperatures its magnitude reaches 70% in a magnetic field of 5 T. Strong electron-electron interactions in…
We study the dc transport properties of (Ga,Mn)As diluted magnetic semiconductors with Mn concentration varying from 1.5% to 8%. Both diagonal and Hall components of the conductivity tensor are strongly sensitive to the magnetic state of these semiconductors. Transport data obtained at low temperatures are discussed t…
Mass production of uniform wurtzite-ZnS nanobelts is achieved by a simple thermal evaporation method using Au as the catalyst. The as-synthesized ZnS nanobelts are single crystalline, usually several tens of microns in length and several hundreds of nanometers in width. Most of the nanobelts grow along [01 1̄ 0] direc…
A new strategy, dendrimer bridging, is developed for simultaneous formation and functionalization of biocompatible and bioaccessible semiconductor box nanocrystals a dendron box around each colloidal semiconductor nanocrystal. CdSe plain core or CdSe/CdS core/shell nanocrystals coated by a monolayer of organic dendron…
A novel sol-gel route to c-axis orientated undoped and Co, Fe, Mn and V doped ZnO films is reported. Sols were prepared from a hydrated zinc acetate precursor and dimethyl formamide (DMF) solvent. Films were spin-coated on to hydrophilic sapphire substrates then dried, annealed and post-annealed, producing almost pure…
A hybrid scheme between large-scale electronic structure calculations is developed and applied to nanocrystalline silicon with more than 10$^5$ atoms. Dynamical fracture processes are simulated under external loads in the [001] direction. We shows that the fracture propagates anisotropically on the (001) plane and rec…
The effects of crystal size and crystal phase on the upconverted emission of Er3+ in ZrO2 oxide nanocrystals are reported. Green (550 nm) and red (670 nm) upconversion emission were observed at room temperature from the S43/2 and F49/2 levels of Er3+:ZrO2 nanocrystals. It is found that at 850 mW of cw excitation power…
Light converter: The emission of visible light (Vis) upon excitation in the near-infrared (NIR) has been observed for the first time in a transparent solution. Excitation at 975 nm (marked red in the picture) of optically clear colloidal solutions of LuPO4:Yb3+, Tm3+, and YbPO4:Er3+ nanocrystals in chloroform leads to…
Large cavities (≈10–12.3 nm) of cubic (Fm-3m) mesoporous silica without intergrowth are synthesized in the presence of block copolymer templates. The entrance sizes of these cavities can be adjusted in the range of ≈4–9 nm as confirmed by nitrogen sorption studies and an examination of the negative gold replicas. The…
Abstract For Abstract see ChemInform Abstract in Full Text.
We have presented a model of the electron-trapping process at edge-sharing ${\mathrm{SiO}}_{4}$ units that are supposed to exist as structural defects especially at the surface of silica-based materials. It has been shown that the edge-sharing ${\mathrm{SiO}}_{4}$ dimer can trap an electron, giving rise to a paramagne…
Abstract For Abstract see ChemInform Abstract in Full Text.