Applied Mechanics and Materials Vol. 481

Abstract: MgO/XLPE composites, composed of micro-and nanosized MgO material having different particle size as inorganic filler and cross linked polyethylene (XLPE), were prepared and investigated to the space charge dynamics of these composites for high voltage DC insulation. Added MgO material, having 50nm to 1μm in size, were synthesized from the calcination of Mg (OH)₂ nanoplatelets which was controlled by potassium content in Mg (OH)₂, varying the dilution volume ratio of distilled water/ Mg (OH)₂ suspension. MgO/XLPE composites were obtained by thoroughly mixing LDPE and dicumyl peroxide (DCP) as the cross-linking agent and silane modified MgO before kneading to enhance the dispersion degree of the composites. The space charge distributions of the composites were observed by controlling the particle size and content of a dispersed MgO in XLPE matrix. To prevent the breakdown under high DC stress, it was found that the reduction of space charge of MgO/XLPE composite depends upon the smaller size of MgO particle and the its content above 0.5 phr (per hundred part of resin, wt%). MgO material and MgO/ XLPE composites were characterized with TEM, XRD, BET, ICP, and the space charge properties of the composites were measured by a pulsed electro-acoustic method (PEA).

Abstract: This study investigates the optimization of a ZnO-coated TiO₂ working electrode and the effect of this hybrid electrode on the power conversion efficiency of a dye-sensitized solar cell (DSSC). This electrode was fabricated by dipping the TiO₂ electrode with the TiCl₄ treatment in a solution of zinc acetate dehydrate [Zn (CH₃COO)₂2H₂ and ethanol. The effect of the concentration of Zn (CH₃COO)₂2H₂O on the band gap of a working electrode and on the power conversion efficiency of a DSSC was also examined. As the concentration of ZnO decreased to 0.002 from 0.004 mol/L, the band gap of the working electrode decreased to 3.08 eV from 3.87 eV, and the power conversion efficiency () of the DSSC increased to 3.8573% from 3.3514%. Interestingly, the of DSSC with a ZnO-coated TiO₂ hybrid electrode substantially exceeded that of the conventional DSSC due to TiO₂ orbital hybridization and an energy barrier between ZnO and TiO₂ that suppressed the electron recombination.

Abstract: In this paper, we have computed electron tunneling currents in TiN_x/HfSiO_xN/SiO₂/Si (100) MOS capacitors by including a coupling term between transverse and longitudinal kinetic energies which is represented by an electron phase velocity in the gate. The effective mass of the substrate is considered as an isotropic mass. The transmittance was analytically calculated by employing an Airy-wavefunction approach, and the obtained transmittance was then utilized to calculate the tunneling current for different nitrogen compositions in the TiN_x metal gate and the equivalent oxide thicknesses (EOTs) of HfSiO_xN. It was shown that the tunneling current reduces considerably as the nitrogen composition of the TiN_x metal gate decreases. It was also shown that the increase in the EOT reduces the tunneling current. In addition, the tunneling current shows an oscillatory behavior at high oxide voltages.

Abstract: This In this study, we report on the growth techniques of Sr_xLa_1-xTiO₃ visible-light responses photocatalytic films by pulsed laser deposition for the H₂ gas generation system as the fuel cell devices. XRD profile showed SrTiO₃ peaks were obtained at the all films. Bandgap energy of films were decreaed with increasing the La ratio from 3.2 eV to 2.9 eV. Water splitting reaction were observed at the all films, and the maximum value of the gas generation was 7.3 μmol/cm²h at x = 0.7 film.document explains and demonstrates how to prepare your camera-ready manuscript for Trans Tech Publications. The best is to read these instructions and follow the outline of this text. The text area for your manuscript must be 17 cm wide and 25 cm high (6.7 and 9.8 inches, resp.). Do not place any text outside this area. Use good quality, white paper of approximately 21 x 29 cm or 8 x 11 inches (please do not change the document setting from A4 to letter). Your manuscript will be reduced by approximately 20% by the publisher. Please keep this in mind when designing your figures and tables etc.

Abstract: We present an assessment of the stability and dynamics of grain boundaries in graphene for different misorientation angles at finite temperature and up to extremely high temperatures, in particular, for a misorientation angle of 6.6, 14.1, 19.66, 27.8, 38.21 and 46.83. We report a high stability against annihilation up to extreme temperatures.

Abstract: Copper oxides films as promising materials for gas sensors applications were studied. Copper oxide films were deposited onto Si/SiO₂ substrates using a citrate sol-gel method with the subsequent temperature treatment at 150-5000C. These films were characterized by means of secondary electron microscopy (SEM) and X-ray-absorption near-edge structure (XANES) spectroscopy. The prepared films were utilized in NO₂ sensors. The dependences of the NO₂ response on the operating temperature and NO₂ concentration (10-200 ppm) were investigated. The maximum NO₂ response was achieved for the film annealed at 2500C.

Abstract: To develop a new low-temperature crystallization technique, annealing characteristics of a-GeSn/Si (100) structures are investigated. It is revealed that epitaxial growth accompanying Si-Ge mixing is generated at temperatures in the liquid-solid coexisting region of the Ge-Sn system. The annealing temperature necessary for epitaxial growth is significantly decreased by increasing annealing time and/or Sn concentration. Consequently, epitaxial growth at 300°C becomes possible. These findings are expected to be useful to realize next-generation large-scale integrated circuits, where various multi-functional devices are integrated.

Abstract: In this study,MFIS (Metal/Ferroelectric/Insulator/Semiconductor) capacitors whose structure is Al/BFO+Nb/HfO₂/p-Si are investigatedby using Taguchi Method. The effects of leakage current, memory window, and signal-to-noise ratio (S/N ratio) are discussed by different process conditions. As a result, the leakage current and memory window indicate the better performance on th same process condition. The better conditions of this MFIS capacitoroccur in rapid thermal annealing (RTA) at 700°C, 5W direct current (DC) power of Nb sputtering and 15 of argon-to-oxygen ratio for laekage current and memory window.Oxygen vacancies were reduced bydoping niobium (Nb) that Nb ions replace ferrum (Fe) ions with RTA at 700°C. The more Nb dopesthe more Nb ions replace Fe ions. Butthe excessive Nb induces to increase the leakage current and reduce the memory widow.

Abstract: We demonstrated a metal-semiconductor-metal type GaN UV sensor for the first time by using multi-layer graphene as a Schottky electrode. Multi-layer graphene shows good Schottky electrode characteristic and fabricated UV sensor shows good UV response characteristics. The maximum dark current density and photo-responsive current density were 6.42 × 10^-9 A/cm² and 5.57 × 10^-5 A/cm² at the 10 V bias, respectively. UV/visible rejection ratios were higher than 10³ with each applied bias from 1 V to 15 V.

Abstract: Heat generated during wire saw slicing can cause silicon temperature raise and make silicon wafer warpage, especially for larger silicon wafers. In order to study the wire saw effect on silicon temperature during slicing process, three kinds of wire saw, mainly semi-fixed abrasive wire saw and traditional wire saw, are applied for slicing silicon ingot. In this paper, the thermocouple is used to measure the temperature of the silicon during wire saw slicing. The experiment results show that the temperature of the silicon increases along with the wire saw working direction and reaches maximum value near the outlet position of silicon. The temperature of the silicon sliced by semi-fixed abrasive wire saw is lower than that sliced by traditional wire saw.