Single crystal

About: Single crystal is a research topic. Over the lifetime, 59617 publications have been published within this topic receiving 870828 citations.

The crystal structure of η-Cu3Si precipitates in silicon

Abstract: The crystal structure of Cu-Si precipitates in silicon has been studied by means of transmission electron diffraction and microscopy. The precipitates are shown to be of the equilibrium Cu3Si phase, probably of the low-temperature η” form. Consistent with earlier X-ray diffraction data for this phase, the crystal structure of the precipitates is determined to be based on a trigonally distorted b.c.c. arrangement. The lattice is orthorhombic (C), and is a two-dimensional long-period superlattice, which it is suggested is based on the intermediate-temperature η' phase; lattice parameters aη” = 76.76, bη” = 7.00, cη” = 21.94 A. On the basis of the diffraction data for the precipitates, it is suggested that the ηand η' phases are both trigonal, space groups R{\bar 3}m and R{\bar 3} respectively, with lattice parameters aη = 2.47 A, αη = 109.74° and aη' = 4.72 A, αη' = 95.72°.

Complex oxide scintillators: Material defects and scintillation performance

Abstract: An overview of recognized structural defects, impurities and related trapping levels and their role in the scintillation mechanism is provided and discussed in single crystal materials belonging to tungstate, Ce- or Pr-doped aluminum perovskite, garnet and finally to Ce-doped silicate scintillators. New achievements and open problems in deeper understanding of electron and hole self-trapping phenomena and of the nature of defects in the crystal structure and their ability to localize migrating charge carriers are indicated. Fast optical ceramics and nanocomposite materials are pointed out as possible future advanced scintillators. Such novel technologies can in principle explore materials which are not available in the bulk single crystal form, but their figure-of-merit is dramatically dependent on the surface-interface defect states and related trapping and nonradiative recombination phenomena. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

In situ synthesis of carbon-doped TiO2 single-crystal nanorods with a remarkably photocatalytic efficiency

Abstract: Incorporating dopants into the TiO2 single crystals lattice is a big challenge because single crystal has a high crystallinity and the nucleation and growth of TiO2 single crystals is readily subjected to the interference of the dose of dopant precursors. Here, we propose an in situ synthetic strategy for the construct of carbon-doped TiO2 single crystal nanorods using CPS/TiO2 as the precursors of TiO2 nanorods and carbon source via a facile hydrothermal route. This technique involves the preparation of cationic polystyrene spheres (CPS), sequential deposition of TiO2 precursor, hydrothermal reaction, and the pyrolysis of CPS in a N2 atmosphere at 450 °C. The morphology and structure of as-prepared C-TiO2 single crystal nanorods were characterized by TEM, SEM, STEM Mapping, XRD, UV–vis spectroscopy, and XPS. All results confirm the carbon doping in the as-prepared TiO2 single crystal nanorods. As a result of unique microstructure, the resulting TiO2 exhibits remarkably visible-light photocatalytic efficiency for the degradation of organic pollutants including methylene blue (MB), Rhodamine B (RhB) and p-nitrophenol (PNP). Therefore, the current study provides a new insight for incorporating dopants into the TiO2 single crystals lattice.