Morphologies and properties of well-aligned ZnO films were controlled using zinc nitrate-hexamethylenetetramine aqueous solution with the addition of polyethylenimine as a surfactant. The addition of polyethylenimine proceeded to form porous ZnO whisker films by preferential adsorption to nonpolar crystal faces and modifications of the surface free energy and growth rate. Dense ZnO films showed high transmittance of 80 %, while porous ZnO whisker films adsorbed organic dye molecules, and showed high intensity of fluorescence and high photo-induced current, because the films provided a large interior surface area which can capture large amounts of dye molecules on the surface of ZnO nanocrystals.

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Novel fixation method of fine particles on polyolefin surfaces has been proposed, that is, room-temperature treatment in an aqueous solution of coupling reagent (3-methacryloxypropyltriethoxysilane) with the suspended fine particles.By this method, extra function can be added to the polyolefin with no degradation of physical properties. A plate crystal and lamellar structure were observed by PE thread and filler-less PE plate which can fix W particulates, respectively. On the other hand, alignment of the macromolecule was not observed by filler-less PE plate and PE plate with a filler which were heat-treated.It was suggested that W particulates are fixed by the hydrophobic group interaction of CH basis of the end group of a binding material molecule and PO base material surface. These results become knowledge important also about the application possibility to that of the other base materials of this technology.

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We tried to synthesize perovskite-type oxyflorides BaMO₂F (M=Sc, In) under ambient and high pressure. As a result, the BaMO₂F (M=Sc, In) could be synthesized under ambient and high pressure and only ambient pressure, respectively. This result indicates that these compounds are stable under ambient pressure. According to the powder X-ray diffraction, the anions is considered to be distributed randomly in BaMO₂F (M=Sc, In). The anions of BaMO₂F (M=Sc, In) seems to be rearranged during fluoridation reaction.

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Barium titanate (BaTiO₃) powders were synthesized by a solid-state reaction in water vapor atmosphere from commercially available BaCO₃ and TiO₂ (rutile). The formation of BaTiO₃ was accelerated by water vapor and BaTiO₃ powders with the same particle size with that obtained in air were prepared in water vapor atmosphere by calcination at low temperature for a short time. The formation kinetics obeyed the Jander equation, which suggested the reaction was controlled by diffusion. The apparent activation energy for the formation of BaTiO₃ in air and water vapor atmosphere was estimated to be 354.9 kJ/mol and 124.5 kJ/mol, respectively. Water vapor is considered to attack surface Ti-O-Ti bonds in the TiO₂ to accelerate BaTiO₃ formation.

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Ultra sonic pyrolysis system (USPS) is one of the useful powder preparation methods for various hybrid powders. Also, it has some advantages for the preparation of the homogeneous powders with relatively narrow particles size distributions. In this study, spherical particles composed of mesoporous silica were synthesized by this USPS technique. In addition, the synthesis of mesoporous silica with a metal was attempted to develop high performance and expand applications of mesoporous materials by this USPS method. Results of X-ray and TEM observation indicated that the spherical particles of mesoporous silica with the hexagonal mesoporous structure were successfully synthesized by USPS.

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Dense yttrium oxide films were prepared by aerosol deposition process for semiconductor industry. The films could be formed on various substrates such as aluminum alloy, alumina, and quartz at room temperature. The film had an excellent plasma resistance compared with Y₂O₃ sintered bulk and Y₂O₃ spraying because of its fine structure and high density. According to SEM observation, the microstructure of the film did not change even after plasma exposure. A usable coating area is 600mm X 600mm by stabilization of the aerosol beam and optimization of the deposition conditions. Broad application is expected in plasma-etching machinery.

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The nitridation process of Eu-doped AEAlSi (AE=Ca, Sr) was investigated by thermogravimetry-differential thermal analysis (TG/DTA) to improve the method for synthesis of AEAlSiN₃:Eu nitride phosphors. The nitridation reactivity was dependent on alkaline earth elements. For Sr_xEu_yCa_1-x-yAlSi with a high Sr content, nitridation proceeded efficiently at the melting point of the intermetallic compounds. A highly efficient process for large-scale production of Sr_xCa_1-xAlSiN₃:Eu (SCASN) phosphor was developed taking advantage of the characteristic nitridation reaction at the melting point.

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Ce doped glass has a great potential to be utilized as a rewritable optical memory media by controlling photoluminescence (PL) intensity of Ce ions. In this study, we selected Na₂O-CaO-B₂O₃-Al₂O₃-SiO₂ system as a host glass because of its superior chemical durability, and investigated influences of ultraviolet light irradiation and subsequent heat treatment on PL properties of the samples. The as-quenched samples showed blue emissions due to Ce³⁺ ions and UV light irradiation made their PL intensities decrease depending on the glass composition. The heat treatment let their PL intensities recover initial ones before irradiation. These changes are considered to derive from electron transfers between Ce ions and the glass networks.

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In this study, Mg doped ZnO particles were prepared using a solution technique. When 10 mol % of Mg (as a row material: Mg(NO3)2) was added to the solution of Zn(OC2H5)2, the XRD pattern of the synthesized particles corresponded to ZnO after drying and heating at 1173K. Since the diffraction peaks of MgO were not detected in the obtained ZnO particles, 10 mass % of Mg seemed to be perfectly solved in ZnO. Farther, then the synthesized ZnO particles showed 300 nm in size.

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(100-x)Ga₂O₃-xMO powders (M: Mg, Ca, Zn, Sr and Ba, x: mol%) were prepared by a solid-state reaction. In Ga₂O₃-MO (M: Mg and Ba) powders, no strong luminescence band appeared. On the other hand, in (100-x)Ga₂O₃-xMO (M: Ca, Zn, and Sr x = 25-50) powders, the luminescence bands due to the self-activation centers of GaO₄^5- and GaO₆^9- appeared at 360 and 399 nm under the excitation of 250 nm. In (100-x)Ga₂O₃-xZnO powders (x = 0-75), the luminescence band related with a gallium-oxygen vacancy pair also appeared at the center wavelength of 432 nm. In this study, 49Ga₂O₃-51ZnO powder showed the strongest blue luminescence by a gallium-oxygen vacancy pair.

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Eu3+ activated Y2O3 nanomaterials were prepared via hydrothermal conditions under sub critical temperature and at high pressure (40 MPa). The as obtained materials are Eu3+ activated Y(OH)3 nanomaterials. The precursor materials were calcined at 500oC to obtain Eu3+ activated Y2O3 nanomaterials. The precursor materials were synthesized with different morphology such as sphere, rod, and bundles of rod. XRD, FESEM, TG-DTA and PL measurements were carried out. The calcined materials exhibited interesting optical properties. The bundles of rod particles showed higher photoluminescence around 610 nm than the sphere and bundles of rod particles.

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LaF3:Eu3+ nanocrycals were prepared through a hydrothermal route, with cetltrimethylammonium bromide (CTAB), as a cationic surfactant, It was found that crystallization and luminescence properties of LaF3:Eu3+ nanocrystals were greatly affected by the CTAB concentration and calcination temperature. The LaF3:Eu3+nanocrystals synthesized with 0.006mol/L CTAB and heated at 600oC exhibited the highest luminescence

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Photoluminescent properties of Cr³⁺ doped in Ga₂O₃-In₂O₃ and AlTaO₄-AlNbO₄ solid solutions were examined in order to see the energy structure of these solid solutions. Ga_2-(2x+y)In_2xO₃:Cr_y showed a ruby-line (694nm) and a broad (750~1000nm) emission. The broad emission shifted to longer wavelength with increasing the ratio of In. In contrast, the both emissions (720~740nm and 800~1200nm) shifted to longer wavelength with increasing the ratio of Nb for Al_1-yTa_1-xNb_xO₄:Cr_y. Thus, the NIR emission of Cr³⁺ was changed by the host of solid solutions and the composition.

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A hexanuclear lanthanide (Ln) cluster [Ln₆O(OH)₈(H₂O)₁₂(NO₃)₆](NO₃)₂·4H₂O (=Ln₆) was used as a precursor of up-conversion (UC) phosphor Y₂O₃:Er,Yb, aiming at control of dopant dispersion in the host. Two doping procedures were carried out; (i) sources (Ln₂O₃) of Er, Yb, and Y were mixed in advance of Ln₆ preparation, (ii) Er₆, Yb₆, and Y₆ were separately prepared and their mixture was dissolved in DMF. The samples of both procedures were pyrolyzed (800 °C 5h) to yield Y₂O₃:Er,Yb. The UC emission intensity of the sample obtained for (ii) was 3 times as larger as that for (i) despite their equivalent Y:Er:Yb= 96:1:3 compositions.

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Single crystals of a new tin titanate containing Sn2+, Sn2TiO4 was prepared by high temperature reaction in an evacuated quartz tube and its crystal structure was determined by using single crystal X-ray diffraction data. This new compound crystallized in the tetragonal space group P42/mbc with a = 8.490(2) and c = 5.923(3) Å, Z=4 and the final R factors were R=0.0497 and Rw=0.0676 for 354 unique reflections. This tin titanate was isostructural with the low temperature form of Pb3O4(Pb2+2Pb4+O4).

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Structure of BaTi₂O₅ glass synthesized from levitated liquid was revealed by a combination of high-energy x-ray diffraction and neutron diffraction with the aid of reverse Monte Carlo (RMC) simulation technique. We found that the connection of TiO₅ polyhedra forms network structure with both corner- and edge-sharing of oxygen. Furthermore it is suggested from the RMC model that the distribution of oxygen around barium is random.

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Eu doped Li-Nb-Ti oxide solid solutions were prepared by firing at 1120 degree C for 24 hours. When the sintering time was 10 hours, the solid solutions did not have a superstructure. It was observed by XRD and TEM that the composition of 20mol%-TiO₂ and 25mol%-TiO₂ in the solid solutions had a superstructure. Sintering 1120 degree C for 24 hours effected to improve the luminescence of the solid solutions. And improving the solid solutions with superstructure showed a pronounced increase.

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In-situ Raman spectroscopy system under microwave irradiation was designed and constructed to study the mechanism of microwave heating. Raman shift of ZnO ceramics were investigated as a function of temperature elevated by the conventional and microwave heating. As a result, A1 mode Raman shift decreased with rising the temperature only by microwave, though no significant difference between both heating methods for the other modes was observed. It is expected that A1 mode lattice vibration can be excited and enhanced by alternate electric field of microwave. Therefore the results suggested that some particular vibration is excited by microwave at first and elevated the temperature of a sample as a whole.

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We have refined the crystal structures of high-temperature paraelectric Pnna KTP and low-temperature ferroelectric Pna21 phases above 973 K for the first time. We present here the experimental evidence of the coexistence of order-disorder and displacive nature in the ferroelectric-paraelectric phase transition of KTP.

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We carried out XAFS study for NaNbO₃-KNbO₃ based ceramics including (K_0.44Na_0.52Li_0.04)(Nb_0.84Ta_0.10Sb_0.06)O₃ ceramics (LF4) to elucidate a relationship of local structures of B site atoms (Nb, Ta, and Sb) with piezoelectric properties. Nb-K edge XANES showed that the coordination environment of Nb-O shell in LF4 was close to that in NaNbO₃. Nb-K edge EXAFS exhibited that the coordination environment of Nb-M (M = Nb, Ta, or Sb) shell in LF4 resemble that in KNbO₃. The same analysis was carried out at Ta-L₁, Ta-L₃ and Sb-K edges. We found that Sb has an important role for the coordination environment of Nb and Ta atoms in LF4.

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The site selective analysis of BaTiO3 by Cs-corrected STEM-EDS was performed in order to identify substitution sites of rare earth elements. It was found that Sm ion which was relatively large replaced A site, and Yb ion which was relatively small replaced B site. Dy and Y ion seemed to replace both sites, and the site preference seemed to depend on other additional ions. This technique is available as the confirmation method of substitution site control.

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We have made cross-sectional TEM observations of p-type wide gap semiconductor LaCuOSe:Mg thin film grown by the reactive solid phase epitaxy method on magnesium oxide substrate. We confirmed epitaxial relationship between the film and the substrate from the electron diffraction. Layered structure of the compound, which is composed of alternate stacking of La-O and Cu-Se layers, was directly observed by HAADF-STEM images. At the film/substrate interface, a peculiar atomic structure which is different from the bulk compound was observed.

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