Applied Mechanics and Materials Vols. 275-277

Abstract: This paper presents a physical-based model for accumulation PMOS capacitor based on strained-Si/SiGe material. With this model, the physical mechanism of the “plateau”, observed in accumulation region of the C-V characteristics of the strained-Si(SSi)/SiGe PMOS capacitor, is studied. The results from the model show excellent agreement with the experimental data. The proposed model can provide valuable reference to the strained-Si device design and has been implemented in the software for extracting the parameter of strained-Si MOSFET.

Abstract: Absolute luminous flux and quantum yield for multichannel transition emissions have been determined in samarium ion (Sm³⁺)-doped cadmium-aluminum-silicate (CAS) glasses under the pumping of blue light emitting diode (LED) using an integrating sphere of 30 cm diameter, which connected to a CCD detector with a 400 μm-core optical fiber. The radiant flux and luminous flux for the visible transition emissions (550–750 nm) of Sm³⁺ under the blue LED excitation were solved to be 123 μW and 32 mlm, respectively, which occupied 1.51% and 7.16% of the whole. The total quantum yield of the visible fluorescence of Sm³⁺ has been calculated to be 2.52%. Investigation on optical radiation parameters for multichannel visible transition emissions of Sm³⁺ in CAS glasses provides a reference in developing luminescence and display materials.

Abstract: Hamiltonian dual equation of plane transversely isotropic magnetoelectroelastic solids is derived from variational principle and mixed state Hamiltonian elementary equations are established. Similar to the Hamiltonian formulation in classic dynamics, the z coordinate is treated analogous to the time coordinate. Then the x-direction is discreted with the linear elements to obtain the state-vector governing equations, which are a set of first order differential equations in z and are solved by the analytical approach. Because present approach is analytic in z direction, there is no restriction on the thickness of plate through the use of the present element. Using the propagation matrix method, the approach can be extended to analyze the problems of magnetoelectroelastic laminated plates. Present semi-analytical method of mixed Hamiltonian element has wide application area.

Abstract: The effect of high-k material on gate threshold voltage for double gate tunnel field-effect transistor (DG-TFET) is studied in this paper. By physically derived the model of threshold voltage for DG-TFET, the quantitative relationship between threshold voltage and gate length is also discussed. It is shown that the proposed model is consistent with the simulation results, and can also easily predict the improved performance on the gate threshold voltage when using high-κ dielectrics and the limited effect on gate threshold voltage when changing the gate length.

Abstract: The absorbing properties of single layer microwave absorbing materials containing frequency selective surface have been analyzed by a finite element method. Absorbing materials with optimum absorbing performances are fabricated according to the numerical simulation results. Experiments are carried out to validate the analytical method. The results show that the presence of the frequency selective surface can significantly improve the absorbing properties of the single layer microwave absorbing materials if proper parameters are chosen, promising great potentials in the microwave absorption applications.

Abstract: In the field of the flash radiography scattering is one of the most important affecting factors in determining the object information. A state-of-the-art optical component called anti-scatter grid has been used in high energy X-ray radiography. But the application for such kind of module in sub-megavolt (100 keV ~ 1MeV) flash radiography has not been mentioned yet. Recently our group has designed a new grid which was different with the products either in high energy X-ray radiography or in low energy mammography. The grid was manufactured and then tested in a 450 keV flash radiography source. The experimental results indicated that the grid’s anti-scatter capability was superexcellent. The Monte Carlo simulation also confirmed the experimental conclusion and the scattered to primary ratios with and without the grid were evaluated quantificationally.

Abstract: The CuInSe₂ compound was prepared by paste coating and electrodeposition-selenization. Observed by scanning electron microscopy (SEM), the surface morphology of CuInSe₂ thin films was improved by compaction. The result of the present work implied that the CuInSe₂ film with smooth surface could be obtained under the pressure of 500 MPa at 60 °C.

Abstract: Thermodynamic properties of the heavy metal germanium tellurite (NZPGT) core and cladding glasses have been investigated. Coefficient of thermal expansion (CTE) and softening temperature (Ts) of the Er³⁺⁄Yb³⁺ codoped NZPGT core glasses were identified to be 1.89×10^–5 °C^–1 and 343 °C, respectively. Glass transition temperature (Tg), onset crystallization temperature (^Tx), peak temperature of crystallization (Tc), temperature difference value (ΔT) and thermal stability parameter (H) of the core glasses were solved to be 290 °C, 412 °C, 470 °C, 122 °C and 0.42, respectively, and the corresponding vaules of cladding glasses were derived to be 290 °C, 391 °C, 400 °C, 101 °C and 0.35. The investigation results indicate optical fiber drawing of Er³⁺⁄Yb³⁺ codoped medium-low phonon energy NZPGT glasses can be achieved in the temperature range 345—380 °C, which provides a valuable temperature reference for further high-quality optical fibers drawing in developing optical devices.

Abstract: The aluminum oxide (Al₂O₃) films are grown on n-type Si-(100) substrate by electron beam evaporation at substrate temperature 500°C~800°C. The Al₂O₃ film surface morphology is characterized by atom force microscopy (AFM) to evaluate the grain microstructure, and the residual stress was investigated by wafer stress analyzer. The results show that different substrate temperature is important condition to the properties of Al₂O₃ film. Microstructure characterization indicates that the film surface at low substrate temperature is smoother, and the surface roughness of these Al₂O₃ films is in the range 1-6 nm. The residual stress increases with increasing the substrate temperature, while the stress decreases after annealing in N₂ condition. It also can be concluded that the microstructure is correlated with residual stress.

Abstract: A trinuclear Chromium(III) complex [Cr3(μ3-O)(μ2-PCBA)6(CH3OH)3]NO3∙H2O∙CH3OH (HPCBA = 4-Chlorobenzoic acid) has been synthesized and characterized by single-crystal X-ray diffraction, IR spectra, UV-Vis absorption spectra and elemental analysis, which belongs to monoclinic, space group P21/c with a = 12.443 (3), b = 24.543 (5), c =22.094 (7)Å, α = 90°, β =115.76 (2) °, γ =90°, V = 6077 (3)Å3, Z = 4.The surface electron behavior of the chromium complex has been studied emphatically by surface photovoltage spectroscopy (SPS). Structural analyse indicate that the complex is molecular complex. The result of SPS show that there is positive photovoltage response bands within 300–800 nm, which indicate that it possess obvious photoelectric conversion properties. There was a good correlation between the SPS and UV-Vis absorption spectra.