The quality of interface between ultrathin silicon dioxide films and their silicon (Si) wafers was characterized using room-temperature photoluminescence (RTPL) and Raman spectroscopy. Three types of low-temperature (350 °C or room temperature) oxide films on Si grown by different techniques were measured and compared with Si wafers having native oxide and high-temperature thermally grown oxide films. Significant RTPL spectra and intensity variations were measured among low-temperature oxide films. Very strong excitation wave length dependence of RTPL spectra and intensity was observed from the low-temperature oxide films on Si whereas the RTPL spectra and intensity from Si with native oxide and thermally grown oxide films were consistent. Stress in the Si lattice, with different low-temperature oxide layers, showed noticeable differences depending on the oxidation technique used. Key device performance parameters of image sensor devices fabricated using three different low-temperature oxide films showed good correlation with the RTPL and Raman measurement results. The RTPL spectra and Raman shifts are very sensitive to the quality of the oxide/Si interface and can be used as an interface quality monitoring technique.

Al–7Si/gray iron bimetal composites with a sound metallurgical bonding were obtained by a gravity die casting process. The surface treatments of the gray iron specimen including fluxing and hot dipping were applied to forming a complete metallurgical bonding layer at the Al–7Si/gray iron interface. In addition, the effect of Mn in dipping bath on the microstructure of the Al–7Si/gray iron interfacial bond zone has been studied in an Al–7Si alloy containing five different levels of Mn ranging from 0 to 5 wt%. Microstructure analysis indicates that addition of Mn in dipping bath can eliminate the harmful needle-like phase (β-Al5FeSi) as the Mn content is no less than 1.5 wt% and also plays an important role in facilitating the growth of intermetallic phases [α-Al15(FexMn1−x)3Si2] and the metallurgical bonding layer. The sound metallurgical bonding formed at the Al–7Si/gray iron interface is attributed to combining the effect of surface treatments and selection of Mn content.

In this article we develop an analytical theory that correlates the macroscopic curvature of stressed film/substrate systems with the microscopic in-plane and out-of-plane deflections of planar rotators. We have extended these stress-deflection relations in the case of nonlinear stress fields and validated the results with the aid of finite element simulations. We use this theory to study the heteroepitaxial growth of cubic silicon carbide on silicon (100) and discovered that, due to defects generated on the silicon substrate during the carbonization process, wafer curvature techniques alone may not enable determination of the stress field in the grown films either quantitatively or qualitatively.

The monomer dimethylaminoethyl methacrylate (DMAEMA) was cross-linked by clay Laponite XLG and Laponite XLS, respectively, in situ free-radical polymerization to prepare nanocomposite gels (named as G-NC gels and S-NC gels). From the analysis of yield, transparency, Fourier transform infrared spectroscopy, x-ray, and scanning electron microscopy, it was proved that the clay Laponite XLS is an appropriate cross-linker for preparing PDMAEMA NC gels with better homogeneous and higher yield due to the uniform dispersion of clay in gels. The resulting S-NC gels show obvious temperature and pH double sensitiveness, and the lowest critical solution temperatures of gels with a low clay content are close to the temperature of the human body, which makes this gel a potential candidate for application in drug release. Comparing with the gels cross-linked by a chemical cross-link agent, the S-NC gels exhibit a considerable improvement in the mechanical properties, swelling ratio, and deswelling rate. The properties of S-NC gels could be adjusted by controlling the content of clay.

A series of TiO2 samples were prepared from the precursor P25 using impregnation method followed by a calcination. The phase compositions of the samples were controlled by addition of various additives, including NaNO3, NaHCO3, Na2SO4, Na3PO4, Na2SiO3, and Na2MoO4. X-ray diffraction patterns demonstrate that the phase transformation from anatase to rutile can be suppressed to a different extent by these additives. Photocatalytic H2 production reactions were performed in methanol aqueous solution. The catalysts, with the addition of NaNO3, NaHCO3, and Na2SO4, show a great improvement in the H2 production activity, while others show a negative effect. This indicates that both the phase structure and the properties of the additives are important for the photocatalytic activity. Infrared spectra of pyridine adsorption on the catalysts reveal that the decreased acidity of the samples may be responsible for the suppressed CO production in the photocatalytic methanol reforming.

A CO2-pulsed laser plasma deposition (CO2-PLD) system is installed and used for the quick synthesis of various hexagonal boron nitride (h-BN) and zinc oxide (ZnO) nanostructures. Each part of the CO2-PLD system, such as focusing of laser beam on the target surface, sample holder, shutter, heater, type of the gas, and gas flow rate, can be easily controlled independently to fit different experimental conditions. After installation of the system, a series of experiments were conducted using hBN and ZnO targets. Scanning electron microscopy images showed that the entire surface (2 × 2 cm2) of the substrate is covered with the conical- and disk-shaped BN nanostructures and web-like highly dense ZnO nanowires, indicating a significantly short-time approach to grow mass product nanostructures. Raman spectroscopy identified the hexagonal structure of the synthesized samples.

Porous thermoplastic polyurethane (TPU) membranes were produced by the electrospinning process. Two different TPUs and their blends were used to investigate the effects of material composition, solution concentration, and rheological properties on the microstructure, fiber diameter, and fiber diameter distribution of the electrospun membranes. The ratios of hard and soft segments in the solutions were adjusted by varying the blend ratios of TPUs dissolved in N, N-dimethylformamide. The solutions with higher TPU concentrations and more hard segments exhibited a higher viscosity, larger storage and loss moduli, and greater electrospun jet stability. Solutions with concentrations around the critical chain entanglement concentration (Ce) produced bead or beaded fiber structures, while bead-free fibers of a uniform diameter were obtained when the concentration increased to about two times that of Ce. Relationships between the electrospun fiber diameter, the Berry number, and the normalized concentration of the solutions were studied as well.

Ultrathin SiC buffer layers have been grown on Si (100) substrates by atmospheric pressure chemical vapor deposition. The evolution of buffer layer morphological properties as a function of carbonization parameters is investigated by atomic force microscopy. Based on the quantitative analysis of the dependences of void density, void depth, void width, and surface roughness on carbonization parameters, a buffer layer growth model is proposed, and the effects of carbonization parameters on buffer layer morphology are clarified. The void density is related to the carbonization temperature, temperature ramp-up rate, and C3H8 concentration by affecting the initial SiC nuclei density. The void size is evolved with processing time and mainly dependent on the carbonization temperature but slightly affected by C3H8 and H2. The buffer layer morphology is deteriorated with increasing H2 flow rate when the C3H8 concentration is fixed.

Using titanium sulfate, Ti(SO4)2, as precursor and sodium hydroxide, NaOH, as adjusting reagent, pure brookite, pure anatase, and mixed-phase titanium dioxide (TiO2) with tunable brookite/anatase ratios were synthesized via a hydrothermal process. The samples were characterized by x-ray diffractionspectrometry, ultraviolet-visible diffuse reflectance spectrometry, transmission electron microscopy, and Brunauer-Emmett-Teller measurement. Photocatalytic degradation of Rhodamine B in aqueous solution served as a probe reaction to evaluate the photocatalytic activity of the as-prepared nanocomposites under visible irradiation (λ > 400 nm). The mixed-phase TiO2 exhibits higher photodegradation activity than single phase TiO2. The sample with 63.1% brookite and 36.9% anatase shows the highest degradation activity. Possible mechanism attributing to the enhanced activity was proposed based on the strucutre and surface property of the samples.

Zinc oxide (ZnO)–single-walled carbon nanotubes (SWCNTs) nanocomposite thin films have been grown by chemical bath deposition method. The changes in structural and chemical properties were studied by means of x-ray diffraction, field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR). The average crystallite size of ZnO doped with 0.1 and 0.5 wt% SWCNTs was measured about 14.69 and 17.76 nm, respectively. Texture coefficient of the carbon peak (002) was investigated as more than 3.2995 for ZnO mixed with 0.5 wt% SWCNTs. SEM images revealed the ZnO and SWCNTs entangled between the particles. TEM images estimated the inner and outer diameters of SWCNTs to be about 4.86 and 11.32 nm, respectively. FTIR analysis proved the formation of Zn–O and C bonding in the thin films. The performance of the dye-sensitized solar cells (DSSCs) was found to depend on the loading of SWCNTs. The power conversion efficiency increased from 0.078 to 0.684% after loading with 0.1 wt% SWCNTs. Higher amount of SWCNTs (0.5 wt%) was determined as ineffective in improving the performance of ZnO-based DSSCs.