Materials Literature
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We report the observation of hole cyclotron resonance (CR) in InMnAs/(Al,Ga)Sb heterostructures in a wide temperature range covering both the paramagnetic and ferromagnetic phases. We observed two pronounced resonances that exhibit drastic changes in position, linewidth, and intensity at a temperature higher than the…
In this work we analyze an Aharonov-Bohm interferometer in the tunneling regime. In this regime, current magnification effect which arises in presence of transport currents is absent. A slight modification in the form of a quantum well incorporated in one of the arms leads to revival of current magnification. Systemat…
Metamaterials, which contain engineered subwavelength microstructures, can be designed to have positive or negative ε and μ at desired frequencies. In this letter, we demonstrate a metamaterial which has a “plasmonic” response to electromagnetic waves in the terahertz (THz) range. The sharp change of reflection and tr…
Many nanoparticles have short-range interactions relative to their size, and these interactions tend to be “patchy” since the interatomic spacing is comparable to the nanoparticle size. For a dispersion of such particles, it is not a priori obvious what mechanism will control the clustering of the nanoparticles, and h…
The morphology and optical properties of ZnO nanostructures prepared by thermal evaporation of Zn under different conditions was investigated. ZnO nanostructures prepared in air, dry and humid argon flow, and dry and humid nitrogen flow were characterized by scanning electron microscopy, transmission electron microsco…
Vertically aligned carbon nanotubes were grown at temperatures as low as 120 °C by plasma-enhanced chemical vapor deposition. A systematic study of the temperature dependence of the growth rate and the structure of the as-grown nanotubes is presented using a C2H2/NH3 system and nickel as the catalyst. The activation e…
As-doped ZnO (ZnO:As) films have been characterized. ZnO:As films show p-type characteristics determined by Hall-effect and photoluminescence (PL) measurements. The hole concentration can be increased up to the mid-1017-cm−3 range. The thermal binding energy of the As acceptor (EAth-b) is 120±10 meV, as derived from t…
Well-aligned arrays of ZnO nanoneedles were fabricated using a simple vapor phase growth. The diameters of the nanoneedle tips are as small as several nanometers, which is highly in favor of the field emission. Field-emission measurements using the nanoneedle arrays as cathode showed emission current density as high a…
A p-type ZnO was prepared on a sapphire substrate using P2O5 as a phosphorus dopant. As-grown n-type ZnO films doped with phosphorus showed electron concentrations of 1016–1017/cm3 and these films were converted to p-type ZnO by a thermal annealing process at a temperature above 800 °C under a N2 ambient. The electric…
„Elektrischer Fensterheber“: Im Komplex 1 führt die ligandenzentrierte Redoxaktivität des Catecholat/Semichinon-Redoxpaares zu schneller und reversibler Änderung der Lichtdurchlässigkeit bei λ=940 nm. Durch Aufziehen von 1 auf einen Film von nanokristallinem, Sb-dotiertem SnO2 auf einem leitfähigen Substrat kann die V…
▪ Abstract Chemical reactivity at heterophase interfaces is reviewed with a special focus on metal-oxide and oxide-oxide interfaces. Equilibrium chemistry of interfaces is discussed in terms of processes at the macroscopic and atomic level. The dependency on thermodynamic and crystallographic variables is described an…
Abstract A novel, radical responsive MRI contrast agent based on a gadolinium chelate conjugated to a liposome through a disulfide linker was synthesized, with the aim of pursuing the in vivo mapping of radicals. The liposome was prepared by incorporating a thiol‐activated phospholipid, which was subsequently reacted…
A combination of extended X-ray absorption fine structure (EXAFS), X-ray absorption near-edge structure (XANES), Fourier transform infrared (FTIR), and 17 O nuclear magnetic resonance (NMR) spectroscopies, small-angle X-ray scattering (SAXS), and X-ray diffraction (XRD) has been used to study the atomic structure of (…
Strahlendes Beispiel: Eine bemerkenswerte Verstärkung der Lumineszenz des TbIII-Komplexes 1 wird bei Zugabe von ZnII-Ionen beobachtet (siehe Bild). Durch seine ausgeprägte Selektivität für ZnII-Ionen und eine Lumineszenz-Lebensdauer im Millisekundenbereich eignet sich 1 hervorragend als Prototyp für die Entwicklung la…
Using ab initio and self-consistent-charge density functional based tight-binding electronic structure calculations the possibility that a recently synthesized layered structure of ${\mathrm{Si}}_{2}{\mathrm{CN}}_{4}$ can lead to superhard structures in the spinel or the $\ensuremath{\beta}$ phase is discussed. Both m…
Large arrays of aligned CN x nanotubes were synthesized by radiofrequency magnetron sputtering of a mixture of nanometre-sized graphite and nickel powders in a nitrogen atmosphere. The CN x nanotubes produced assembled into bundle-like arrays standing perpendicularly on the silicon substrates. The nickel nanoparticles…
Co doping on the Mn sublattice of layered ${\mathrm{LiMnO}}_{2}$ suppresses the Jahn-Teller-driven monoclinic distortion in favor of a layered rhombohedral structure. First-principles calculations (within the local-spin-density approximation--generalized-gradient approximation frame-work) using the VASP code, as well…
The first series of lanthanide(III) monobenzoporphyrin liquid crystalline compounds, meso -tetraalkyltetrabenzoporphyrin (TATBP) ytterbium hydroxy, and relative transition metal benzoporphyrin liquid crystalline compounds (4 series, 24 kinds) are reported that display a hexagonal columnar discotic columnar ( Col h, pr…
The intense environment of an electric arc has been used to create MoS 2 core–shell particles. Instead of running the arc in a vacuum chamber under reduced pressure conditions, an arc discharge in water was employed. The arc was run between a carbon cathode and a Mo hollow rod anode whose interior was packed with MoS…
Glass formers are defined as "type B" when they exhibit a distinct Johari-Goldstein (JG) relaxation, but lack an excess loss ("excess wing," EW) in their structural relaxation peak. By studying the dielectric spectra of a well-known type-B glass former under high pressure, we unequivocally show the existence of an EW,…