Growth mechanism of cubic MgO granule via common ion effect.

MgO is a typical wide bandgap insulator with its excellent thermodynamic stability, low dielectric constant, and low refractive index for growing various thin film materials. For this application, it is worth developing and understanding suitable growth method for MgO nanostructure. In this study, cubic MgCO3 have been successfully prepared via hydrolysis control of magnesium salt and alkaline solution with common ions to form nanoflake assembly. An optimum hydrothermal process and its shape evolution of cubic MgCO3 and MgO granules are analyzed. The physicochemical properties of the obtained samples are characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier Transform InfraRed (FT-IR) to show high purity and structural uniformity of magnesium compounds.

Extraction of three-dimensional information of biological membranous tissue with scanning confocal infrared laser microscope tomography.

The "LEXT" confocal laser scanning microscope has been used for the three-dimensional (3D) imaging of the surface of specimens, especially in materials science fields, by the penetration of near-infrared (NIR) light without mechanical cutting, deposition, or other specimen pretreatment. Noninvasive investigation of various biological tissues such as human spinal dura mater, rat aorta, and cornea without the dehydration process was successfully carried out with the "LEXT," in order to access both surface and internal topographic images of the biological structures at a good status of the wet tissue such as in vivo, especially in measuring tissue thickness. The confocal NIR laser microscopy offers the viable means to visualize tissue architecture and its thickness in microdomain to integrate 3D images efficiently. We believe that the "LEXT" has a good application for biological researchers to study biomaterials, and it would be useful as a diagnostic tool in the near future.

Laser marking on microcrystalline silicon film.

We present a compact dot marker using a CW laser on a microcrystalline silicon (Si) thin film. A laser annealing shows a continuous crystallization transformation from nano to a large domain (> 200 nm) of Si nanocrystals. This microscale patterning is quite useful since we can manipulate a two-dimentional (2-D) process of Si structural forms for better and efficient thin-film transistor (TFT) devices as well as for photovoltaic application with uniform electron mobility. A Raman scattering microscope is adopted to draw a 2-D mapping of crystal Si film with the intensity of optical-phonon mode at 520 cm(-1). At a 300-nm spatial resolution, the position resolved the Raman scattering spectra measurements carried out to observe distribution of various Si species (e.g., large crystalline, polycrystalline and amorphous phase). The population of polycrystalline (poly-Si) species in the thin film can be analyzed with the frequency shift (delta omega) from the optical-phonon line since poly-Si distribution varies widely with conditions, such as an irradiated-laser power. Solid-phase crystallization with CW laser irradiation improves conductivity of poly-Si with micropatterning to develop the potential of the device application.

Synthesis of MgO granule and its precursors via common ion effect.

It is well known that the shape and size of inorganic nanostructures have much influence on their optical, electrical and physical properties. MgO is a promising material with potential applications in a variety of fields such as catalyst support, reinforcing reagent and good component in superconductors. In this study, flower-like Mg(OH)2 and cubic MgCO3 have been successfully prepared via hydrolysis control of magnesium salt and alkaline solution with common ions under hydrothermal condition by the formation of nano-platelets assembly. Subsequent calcination converts both Mg(OH)2 and MgCO3 into the corresponding MgO granules of similar flower-like and cubic morphology and size to each precursor. The physical and chemical properties of MgO and its precursors of Mg(OH)2 and MgCO3 are investigated by SEM, XRD, FT-IR, and TGA analysis.