Key Engineering Materials Vol. 508

Abstract: Volatile Complexes Mg(thd)₂(TMEDA) (1) and Cs[Y(ptac)₄] (2) (Hthd = 2,2,6,6-Tetramethylheptane-3,5-Dione, TMEDA = N,N,N’,N’-Tetramethylethylenediamine, Hptac = 1,1,1- Trifluoro-5,5-Dimethylhexane-2,4-Dione) Were Synthesized and Characterized. Thermal Properties of (1) and (2) Were Investigated by TG. The Temperature Dependencies of Saturated Vapour Pressure of Compounds Were Measured by Static (for (1)) or Flow (for (2)) Method. The Obtained Data Were Used for Choosing Temperature Parameters of Deposition Mg- and Cs-Containing Films by CVD Using (1) and (2) as Volatile Precursors. MgO Thin Films Were Deposited on Si (100) by Low-Pressure CVD (LPCVD) and Pulse-CVD in Temperature Deposition Range 673-823K. Cs- and Mg,Cs-Containig Films Were Formed by LPCVD. The Deposited Films Were Studied by SEM and AFM, Correlations between Temperature Conditions of Deposition Processes and Film Characteristics Were Found.

Abstract: Czochralski Growth of Si Crystals Heavily Doped with in Impurity and Co-Doped with Electrically Neutral Impurity C or Ge Was Conducted in Order to Investigate the Solubility and Ionization Ratio of in in Si for Utilizing in Advanced ULSI and PV Devices. The Carrier Concentrations in the Grown in-Doped and (In+C) and (In+Ge) Co-Doped Crystals Were in a Range of 3.5~6.5 × 10¹⁶ Cm^-3, much Lower than the Total Concentration of in Impurity due to the Low Ionization Ratio. Sufficient Increase of Carrier Concentrations by Co-Doping of C or Ge Impurity Was Not Detected for their Low Concentrations in the Grown Crystals Investigated.

Abstract: ααΑαNd³⁺ 0.5% Doped Single Crystal LiCaAlF₆ Scintillator Was Grown by the Micro-Pulling down (µ-PD) Method. Powder X-Ray Diffraction Analysis Was Done and the Grown Crystal Was a Single Phase LiCaAlF₆. it Was Cut and Polished to the Physical Dimension of 1 × 2 × 7 mm³. in Transmittance Spectrum, Nd³⁺ 5d-4f Absorption Observed at 175 Nm and the Transmittance Became 80% at Wavelength Longer than 180 Nm. Excited by 160 Nm, Nd³⁺ 5d-4f Emission Appeared at 180 Nm. X-Ray Induced Radio-Luminescence Spectrum Showed the Similar Feature with the Photoluminescence One. when Coupled with PMT and Irradiated by ²⁴¹Am α-Ray, the Absolute Light Yield Resulted 100 Ph/5.5 Mev α.

Abstract: High Density Antimony-Doped Tin Oxide (ATO) Ceramic Targets Are the Crucial Materials for Preparation of High Quality Transparent Conductive ATO Thin Films in Sputtering Process. In the Present Work, ATO Nanopowders with Different Sb₂O₃ Doping Content (0~10 mol%) Were Used to Fabricate the ATO Nanoceramics by Spark Plasma Sintering (SPS) Technique, which Can Reduce the Densification Temperature and Restrain a Grain Growth. And the Effect of Sb₂O₃ Doping Content (0~10 mol%) on the Density and Microstructure Had Been Investigated. the Results Showed that with the Sb2o3 Doping Content Increase, the Relative Density of ATO Nanoceramics Is Increased and the Resistivity Is Decreased. When the Sb₂O₃ Doping Content Is 10 mol%, the Relative Density Is 97.2% and the Resistivity Is 7.9×10^-2 Ω•cm.

Abstract: Single Crystals of Eu-Doped Calcium Orthoborate Have Been Grown by Micro-Pulling (μ-PD) Technique with Radio Frequency Heating System, and its Transmittance, Photoluminescence and Radiation Responses Were Investigated. In Transmittance Spectra, Eu-Doped Crystal Showed Broad Absorption Band around 200-450 nm, which Is due to the Complex of Charge Transfer (CT) Transition and 4f-4f Transition of Eu³⁺. Intense Eu²⁺ 5f-4f and Eu³⁺ 4f-4f Emission Peaks Were Observed when Excited to 265 nm and 385 nm, and the Calculated Decay Times Were 230 ns and 1.5 ms, Respectively. ²⁴¹Am 5.5 Mev α-Ray Excited Radioluminescence Spectra Indicated both Eu²⁺ 5f-4f and Eu^{Superscript text}3+ 4f-4f Emission Peaks.

Abstract: Ce and Mg Co-Doped LiCaAlF₆ (LiCAF) Single Crystals Were Grown by Micro-Pulling-down (μ-PD) Method and the Optical and Scintillation Properties of Obtained Crystals Were Measured. The Grown Crystals Were Crack-Free and Had 30-50 mm in Length and 2 Mm in Diameter. Absorption Coefficients Were Proportional to the Ce Nominal Concentrations. the Radioluminescence Spectra under 5.5 Mev Alpha-Ray Irradiation Showed Emission Peak at 290 and 310 nm due to Ce³⁺ 5d-4f Transitions, and Were Agreement with those of Ce Single-Doped LiCaF. The Highest Light Yield under 5.5 Mev Alpha-Ray Irradiation of Ce 4% and Mg 2% Co-Doped LiCaF Was Found to Be 0.6 Times than that of Lithium Glass Scintillator GS-20. Comparing the Light Yield of Licaf Samples with the Fixed Ce Nominal Concentration and Different Mg Co-Doped Concentrations, the Light Yield Increased with an Increase of Mg Nominal Concentration. the Alpha-Ray Excited Decay Times Were Constantly 45-50 ns.

Abstract: Ca₃NbGa₃Si₂O₁₄ (CNGS) Is One of the Langasite-Type Crystals and it Is Known as a Piezoelectric Material. We Have Successfully Grown the Shaped CNGS Crystal Using Micro-Pulling-down (μ-PD) Method with Shape Control. However, the Impurity Phases such as Ca-Nb-O Related Compounds Were Detected in the Grown Crystals. The Creation of the Impurity Phases Is Related to Difference in Stoichiometric and Congruent Compositions. Therefore, the Detailed Investigation of Phase Diagram on CNGS Was Carried Out to Prevent the Impurity Phases Creation. It Follows from the TG-DTA Measurements that the Melting Point Systematically Changed with the Ca/Ga Ratio in the Ca_3-xNbGa_3+xSi₂O_14±δ Cmpositions. The CNGS Phase with Ca/Ga = 1.02 Indicated the Maximum Melting Point which Suggests that the Stoichiometric Composition of CNGS Is Different in the Congruent Composition. Furthermore, in the DTA Measurements the Peaks of Impurity Phases Were Detected around 1550 °C for the CNGS Sample with Ca/Ga = 1.02.

Abstract: Hot-Press Sintering, a Method that Could Effectively Decrease the Densification Temperature due to the Applied Pressure, Was Employed to Prepare a New Kind of Ho³⁺ Doped Bi₄Ti₃O₁₂ Ceramics, Bi_3.6Ho_0.4Ti₃O₁₂. The Effect of Preparation Parameters on the Crystal Phase, Density and Microstructure of the Ceramics Were Investigated. at First, Single-Phased Bi_3.6Ho0.4Ti3O12 Powders Were Synthesized from Bi2o3, Tio2 and Ho2o3 Raw Powders by Solid-State Reaction and the Optimum Calcined Temperature Should Be 900 °C. The as-Synthesized Powders Were Further Densified at 750-900 °C to Prepare Bi_3.6Ho_0.4Ti₃O₁₂ Ceramics. Dense (relative Density Was 99.4 %) Bi_3.6Ho_0.4Ti₃O₁₂ Ceramics with a Compact Texture Were then Obtained by Hot-Press at 850 °C, about 150-200 °C Lower as Compared with Pressureless Sintering.

Abstract: Triple Layered Hydration Structure Called Water Nanotube Is Formed in the Nanochannel of New Molecular Porous Crystal {[Co^III(H₂bim)₃](TMA) 20H₂O}_n. The Formation of Regulated Water Network Is Identified by the Infrared Spectroscopy, X-Ray and Neutron Crystal-Structure Analyses. Furthermore, the High Conductivity Exhibiting Activation-Type Behavior Has Been Observed by the Microwave Measurement Employing Single Crystal with Millimeter-Order Length. According to the Observation of Strong Isotope Effect and Distinct Anisotropic Conduction, the Water Nanotube Is Confirmed to Be a Quasi One-Dimensional High Proton Conductor.

Abstract: Ferromagnetic Resonance (FMR) of Epitaxial Fept Thin Films with in-Plane Magnetization Was Investigated by Measuring the Reflection Coefficient (S₁₁) Using Coplanar Waveguides. FMR Signals of Four Fept Films Grown on Mgo (001) Substrates with Different Post-Annealing Temperatures Were Measured, and the Resonant Peaks of Fept Were Successfully Observed. Annealing Temperature Dependence Was Found in the Peak Frequency Shift Depending on the Magnetic Field Applied in the Film-Plane, which Is Attributable to the Difference of Magnetic Anisotropy of Fept Thin Films.