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Znic-based metal–organic framework materials (ZIF-8) show great potential and excellent performance in the fields of sensing and catalysis. However, powdered metal–organic framework makes it easy to lose in the process of application. Herein, we use a simple blending electrostatic spinning method to combine ZIF-8 particles with polyacrylonitrile (PAN) nanofibers. ZIF-8/PAN composite nanofiber membrane. The ZIF-8/PAN nanofiber membrane is characterized by scanning electron microscope (SEM), x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and N2 adsorption–desorption. The results show that the ZIF-8/PAN nanofiber membrane has the characteristic peaks of XRD and FTIR, which are consistent with those of simulated ZIF-8. The specific surface area of ZIF-8/PAN nanofiber membrane increases from 13.5371 to 711.4171 m2 g−1 due to the introduction of ZIF-8 particles. The sensor using the nanofiber membrane as the gas sensing layer shows good response and linear correlation to different concentrations of acetone gas. The minimum detection limit of the sensor for acetone is 51.9 ppm. The blank control shows that the response of the sensor to acetone is mainly due to the introduction of ZIF-8 particles. In addition, the sensor also shows a good cyclic response to acetone. [ABSTRACT FROM AUTHOR]

Calcium zincate microcrystals are successfully prepared with calcium carbonate and zinc oxide as reactants in alkaline solution without protective atmosphere. The structure and composition are analyzed by X-ray powder diffraction (XRD) analysis, thermodiffractometry, scanning electron microscope (SEM), energy dispersive X-ray analysis (EDS), and thermogravimetric analysis (TGA). Electrochemical measurement results prove that the as-synthesized calcium zincate exhibits a good reversibility, a high specific capacity and a good cycling stability. This is a cheap and facile way to synthesize calcium zincate materials which may benefit for mass production of calcium zincate. [ABSTRACT FROM AUTHOR]

Well-aligned and uniform Co0.8Zn0.2Fe2O4 nanofibers (NFs) are prepared by electrospinning via sol—gel and subsequent heat treatment. Each of the as-spun NFs has a diameter of about 300 nm and a smooth surface morphology. The scanning electron microscope (SEM) image shows that the diameter decreases to 70 nm after the Co0.8Zn0.2Fe2O4 NF has been annealed at 650 °C for 3 h. The structure and chemical of Co0.8Zn0.2Fe2O4 NF are investigated by X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDS), respectively. Single phase cubic spinel structure, Co0.8Zn0.2Fe2O4 NF, is successfully obtained after having been calcined at 550 °C in air for 3 h, and a reduced lattice constant of the Co0.8Zn0.2Fe2O4 NF provides the evidence of effective Zn2+ substitution. The magnetic measurements show that the substitution of Zn2+ for Co2+, i.e., the introduction of non-magnetic Zn2+ ions into A sites, can increase the saturation magnetization (Ms) and reduce the coercivity (Hc). The obtained Hc results of different samples reveal that the critical single-domain size of the Co0.8Zn0.2Fe2O4 NF is approximately 44 nm. By doping Zn2+ with different concentrations, the morphologies of Co1−xZnxFe2O4 (0 ≤ x ≤ 0.5) NFs do not show obvious changes. For magnetic properties, the Ms increases and Hc decreases monotonically, respectively. [ABSTRACT FROM AUTHOR]

Influences of the Si doping on the structural and optical properties of the InGaN epilayers are investigated in detail by means of high-resolution X-ray diffraction (HRXRD), photolumimescence (PL), scanning electron microscope (SEM), and atomic force microscopy (AFM). It is found that the Si doping may improve the surface morphology and crystal quality of the InGaN film and meanwhile it can also enhance the emission efficiency by increasing the electron concentration in the InGaN and suppressing the formation of V-defects, which act as nonradiative recombination centers in the InGaN, and it is proposed that the former plays a more important role in enhancing the emission efficiency in the InGaN. [ABSTRACT FROM AUTHOR]

In this article, the arc erosion behaviour of high-purity Ti3SiC2 in vacuum was investigated by x-ray diffraction, scanning electron microscope, energy dispersive x-ray spectroscopy, and micro-Raman spectroscopy. From the results obtained, Ti3SiC2 is unstable due to the high energy intensity and high temperature of the vacuum arc. The dissociation of Ti3SiC2 takes place at the sample surface, resulting in the formation of solid TiCx and gaseous Si. TiCx is ejected from cathode to the surface of anode while Si is evaporated to the vacuum chamber. The micro-Raman results reveal that small amounts of carbon appeared as a by-product of the dissociation of Ti3SiC2, indicating that the Ti–C bonding is broken down under the vacuum arc. [ABSTRACT FROM AUTHOR]

In this paper, a work mechanism based on Newton's cradle model for secondary battery is proposed. ZnlCH3COOLi +Zn(CH3COO)2lLiMn2O4 binary ion battery is a typical Newton's cradle system. Its work process is discussed in detail by cyclic voltammetry (CV), inductively coupled plasma-atomic emission spectrometry (ICP-AES), scanning electron microscope (SEM) and X-ray diffraction (XRD). The charge-discharge curves and cycling calendar life as well as current rate performance indicate that the work mechanism based on Newton's cradle model operates well, the sustainable current rate larger than 20C suggests that this system can offer a considerable high power. [ABSTRACT FROM AUTHOR]

Here the large-area hierarchical Bismuth Molybdate nanowires have been successfully prepared via a facile electrodeposition-heat-method. X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and laser micro-Raman spectrometer measurements were employed to characterize the hierarchical Bismuth Molybdate nanowires. In addition, the as-synthesized hierarchical Bismuth Molybdate nanowires manifest a high specific capacity and good electrochemical stability. [ABSTRACT FROM AUTHOR]

In order to achieve a high level of reliability in rechargeable Li-ion batteries, battery cell materials must maintain good mechanical stability over many cycles. Stresses due to intercalation, phase transition, and thermal loading can cause local fractures in the active materials of Li-ion batteries, as has been experimentally observed. The resulting fracture of the cathode materials is one putative degradation mechanism of Li batteries; it inevitably results in a loss of electrical contact and an increase in the surface area for active material dissolution and SEI layer formation. In this work, we investigate the conditions under which initial defects propagate and form larger fractures in the cathode material (LiMn2O4) during the charging and discharging cycles of electrochemical reactions. Fracture analysis based on the extended finite element method (XFEM) is used to evaluate the effects of current density, particle size and particle aspect ratio on the propagation of defects. Both current density and particle size are shown to be positively correlated with fracture propagation, though not monotonically so in the case of aspect ratio. With an aspect ratio of I .5: 1, a particle with a defect at the center will crack at a low C-rate; this case is one of the most severe among all aspect ratios. [ABSTRACT FROM AUTHOR]

Cobalt-based alloy (Co-30Cr-5.5Mo) is produced by the investment casting process. This alloy complies with the ASTM F75 standard and is widely used in the manufacturing of orthopedic implants because of its high strength, good corrosion resistance and excellent biocompatibility properties. SEM, XRD and microhardness tests are used to examine the mechanical properties of the material. The examined material exhibits the behaviour of indentation size effect (ISE). Our results reveal that Vickers and Knoop microhardness are dependent on indentation test load. The traditional Meyer's law, the proportional specimen resistance (PSR) model and the Hays-Kendall model (HK) are used to analyze the load dependence of the hardness. As a result, the Hays-Kendall model is found to be the most effective to determine the load-independent hardness HLI of CoCrMo alloy. [ABSTRACT FROM AUTHOR]

Sr2SiO4:Eu2+ phosphors were prepared by a conventional solid-state reaction method at a relatively low temperature (1100°C) by using NH4F as a flux. The effect of NH4F flux and Eu2+ doping concentrations on the structural and luminescent properties of Sr2SiO4:Eu2+ was investigated in detail. The structural properties were studied by X-ray diffraction and a field-emission-scanning electron microscope. The blueshift of emission peaks with different Eu2+ concentrations was observed and analyzed. The NH4F flux increased the content of monoclinic β-Sr2SiO4 phase and enhanced the luminescent performance of Sr2SiO4:Eu2+ phosphor significantly, and the NH4F flux is more superior to the NH4CI and Li2CO3 fluxes. Our investigation indicates that Sr2SiO4:Eu2+ is a good light-conversion phosphor candidate for near-UV chip and that NH4F is a good flux for β-Sr2SiO4:Eu2+. [ABSTRACT FROM AUTHOR]

The growth mechanism of the CuO single-crystal nanowires (NW5) for future device applications has been demonstrated using the copper films deposited on CuO-buffered SiO2/Si substrates. The mechanism involves a two-step process: In the first step, hillocks of copper are formed to relieve the compressive stress existing on the copper films at high temperature for a long duration of time in air and then Cu2O phase is formed by the oxidation of the hillocks in air ambient. The second step involves a continuous supply of copper through the porous Cu2O seed and then the transformation of the Cu2O phase to CuO NW. The CuO NW was grown by a continuous supply of both copper from the copper films and oxygen from air. The indispensable requirements for CuO NW growth from the copper films are the presence of compressive stress in the copper films and the presence of the Cu2O seed phase on the copper films at a high temperature in air. [ABSTRACT FROM AUTHOR]

We employed an amorphous citrate precursor (ACP) method to synthesize stoichiometric La0.6Ca0.4CO0.8Ru0.2O3 powders. Result from X-ray diffraction demonstrated a perovskite La0.6Ca0.4CoO3 lattice, indicating the incorporation of Ru3+ at the CO3+ sites. Image from the scanning electron microscope revealed a foamlike microstructure with various pores at 0.5-3 p.m. La0.5Ca0.4Co0.8Ru0.2O1 exhibited a higher H2O2 decomposition rate in KOH solution as opposed to that of ACP-derived La0.6Ca0.4CoO3, which suggested an improved catalytic ability for oxygen reduction reaction (ORR). A similar behavior was observed during the ORR current-potential polarization using La0.6Ca0.4CO0.8Ru0.2O3 supported on Black Pearl 2000 as a gas diffusion electrode. In addition, impedance spectra at the open-circuit voltage and selective cathodic overpotentials also confirmed a smaller charge-transfer resistance for La0.6Ca0.4Co0.5Ru0.2O3. In galvanostatic measurements and lifetime evaluation, La0.6Ca0.4CO0.5Ru0.2O3 demonstrated steady voltage profiles with negligible degradation. [ABSTRACT FROM AUTHOR]

A γ-MnO2 nanomaterial was synthesized by hydrothermally treating an amorphous manganese oxide, which was obtained by the reaction between NaMnO4 and MnSO4 at ambient conditions. It is only in a narrow range of adding an amount of NaOH (e.g., 0.08-0.09 M in our case) that γ-MnO2 can be obtained. The addition of NaOH may affect the radii of hydrated Na+ and, consequently, the formation of γ-MnO2 the related mechanism was discussed. γ-MnO2 was characterized by X-ray diffraction (XRD), scanning electron microscope, transmission electron microscope, and temperature-programmed XRD. γ-MnO2 was also characterized by the combined thermogravimetric/differential thermal analysis-mass spectrometry; accordingly, the annealed forms of γ-MnO2 were prepared and characterized electrochemically. The results show that the γ-MnO2 calcined at 275°C for 10 h showed excellent capacity (296 mAh g-1) with a good rate capability. [ABSTRACT FROM AUTHOR]

By orthogonal design theory, technological parameters of chrysanthemum-like ZnO particles prepared in a hydrothermal process are optimized. This paper reports a set of technological parameters for growing chrysanthemum- like ZnO particles on a large scale. It investigates the morphologies and crystalline structures of the as-synthesized three-dimensional ZnO particles with a scanning electron microscope, x-ray diffractometer and transmission electron microscope, and the possible growth mechanism on the three-dimensional ZnO particles. The experimental results indicate that the values of e', e" and tan δe gradually increase in the X band with the improvement of the developmental level of chrysanthemum-like ZnO particles, implying that the electromagnetic wave absorbing property depends on the morphologies of three-dimensional ZnO particles. [ABSTRACT FROM AUTHOR]

ZnS films were prepared by pulsed laser deposition (PLD) on porous silicon (PS) substrates. This paper investigates the effect of annealing temperature on the structural, morphological, optical and electrical properties of ZnS/PS composites by x-ray diffraction (XRD), scanning electron microscope (SEM), photoluminescence (PL) and I-V characteristics. It is found that the ZnS films deposited on PS substrates were grown in preferred orientation along b-ZnS (111) direction, and the intensity of diffraction peak increases with increasing annealing temperature, which is attributed to the grain growth and the enhancement of crystallinity of ZnS films. The smooth and uniform surface of the as-prepared ZnS/PS composite becomes rougher through annealing treatment, which is related to grain growth at the higher annealing temperature. With the increase of annealing temperature, the intensity of self-activated luminescence of ZnS increases, while the luminescence intensity of PS decreases, and a new green emission located around 550 nm appeared in the PL spectra of ZnS/PS composites which is ascribed to the defect-center luminescence of ZnS. The I-V characteristics of ZnS/PS heterojunctions exhibited rectifying behavior, and the forward current increases with increasing annealing temperature. [ABSTRACT FROM AUTHOR]

This paper reports that diamond single crystals were synthesized from sulfur-added Ni70Mn25Co5+C system under high pressure and high temperature (HPHT). It was found that additive sulfur had inhibited the nucleation and growth of diamond to some extent. X-ray diffraction of the collected sample indicated that under the synthesis conditions, a new compound MnS had been formed through the reaction of additive sulfur with manganese in the catalyst. The MnS has a fcc structure, and its average crystal size was about 30 nm. By scanning electron microscope, the {111} surface of diamond was found to be flat, while there was usually a large depression on the central region of {100}. Further observation showed that there were many small upside-down pyramidal pits in the expression. The results of x-ray photoelectron spectroscopy shows that MnS can only be detected in the depression in the range of detection precision. It was inferred that MnS had been dissolved in the melted alloy during the growth experiment, and precipitated in the sequent quenching process. [ABSTRACT FROM AUTHOR]

Mg-doped GaN nanowires have been synthesized by ammoniating Ga2O3 films doped with Mg under flowing ammonia atmosphere at 850° C. The Mg-doped GaN nanowires are characterized by x-ray diffraction (XRD), scanning electron microscope (SEM), high-resolution transmission electron microscopy (HRTEM) and photo-luminescence (PL). The results demonstrate that the nanowires are single crystalline with hexagonal wurzite structure. The diameters of the nanowires are 20-30 nm and the lengths are 50-100 mm. The GaN nanowires show three emission bands with well-defined PL peak at 3.45 eV, 3.26 eV, 2.95 eV, respectively. The large distinct blueshift of the bandgap emission can be attributed to the Burstein-Moss effect. The peak at 3.26 eV represents the transition from the conduction-band edge to the acceptor level AM (acceptor Mg). The growth mechanism of crystalline GaN nanowires is discussed briefly. [ABSTRACT FROM AUTHOR]

Self-standing and macroporous carbon materials were prepared by using silica opals (colloidal crystal) as a template. Poly(furfuryl alcohol) was synthesized in the interstice of the silica colloidal crystals, followed by carbonization at 1000°C. The silica templates were etched off to give inverse opal carbons. The inverse opal carbons were characterized by scanning electron micrograph (SEM), reflection spectroscopy, elemental analysis, infrared spectroscopy, X-ray diffraction, direct current conductivity, and N2-adsorption/desorption experiments. The SEM images and the reflection spectra indicated periodic porous structures that were negative structures of the silica opal templates. The inverse opal carbons were hard carbons, mainly consisting of amorphous incompletely graphitized structures, and have electronic conductivity of 10² S cm-1. The nitrogen adosorption/desorption experiments clarified that the carbons have large N2-BET (Brunauer-Emmett-Teller) specific surface area resulting from a lot of mesopores, in addition to macropores based on the silica templates. Electric double-layer charging and discharging of the carbons were studied in a tetraethylamnionium tetrafluoroborate/propylene carbonate solution. The electric double-layer gravimetric capacitance and the coulombic efficiency of the inverse opal carbon electrodes in the solution increased with a decrease in the diameter of the silica spheres used for the opal templates and became superior to those of a typical activated carbon. [ABSTRACT FROM AUTHOR]

Synergistic effect of ethylene thiourea (N) and bis-(3-sulfopropyl)-disulfide (SPS) on Cu electrodeposition layer was demonstrated and examined regarding conditions of the morphology, surface roughness, crystal orientation, texture coefficient, and grain size using scanning electron microscope, atom force microscope, and X-ray diffraction. The results show that the surface roughness and grain size were decreased to 4 and 24 nm, respectively, due to the synergistic effect, and Cu(III) is the dominant crystal orientation of the plating surface. Also, electrochemical tests were done to investigate the interaction between N and SPS on Cu electrodeposition which may bring the synergistic effect. The results of cyclic voltammetry, overpotential measurements, and galvanostatic measurements show that N and SPS may interact with each other, adsorb on the electrode surface in a stable way, and then take the synergistic effect in Cu electrodeposition. Compared with that of only SPS added in, the overpotential can decrease further because of this kind of effect, and then the quality of the Cu electrodeposition layer is prominently improved. [ABSTRACT FROM AUTHOR]

Using a nm-level powder fabricated by a wet chemical method as precursor, the CeO2-doped WO3ceramics were prepared by the conventional solid state reaction at sintering temperatures from 600 to 1100?°C. The x-ray diffraction analysis reveals the coexistence of different WO3phases in the samples sintered at temperatures below 900?°C, whereas a single phase appears in the samples sintered above 1000?°C. No new Ce-W compound appears. As the sintering temperature increases, the electrical properties of the samples display an interesting transformation from linear to nonlinear behaviour. The measurements of scanning electron microscope, complex impedance and electrical stability indicate that a lot of grain boundary regions in the samples sintered at low temperatures strongly influences the electrical transportation. Therefore, the electrical nonlinearity is due to a basic process controlled by the back-to-back Schottky barriers at grain boundaries with suitable thickness as well as the coexistence of phases. [ABSTRACT FROM AUTHOR]

In our previous study, an instrument for characterizing mechanical properties under multi-mechanical load and multi-physical field coupling conditions was designed and constructed. Given the structural interference, the linear and shear strains in tension–torsion coupling testing were measured indirectly using linear and circular grating encoders rather than the extensometers in a conventional material testing machine. Accordingly, to correct the experimental curves measured using grating encoders, a correction method was proposed using equations based on the analysis of specimen geometry and instrument structure by elasticity theory. The feasibility of the correction method under single load and tension–torsion coupling loads were verified by the contrast tests among curves of grating encoders’, curves of extensometers, and results of a digital image correlation (DIC) measuring system. Test results illustrate that the correction method can convert the displacement measured using grating encoders to the deformation of the specimen in the elastic range, and the measuring error of elastic moduli can be reduced to approximately 1/5–1/50 of the original measurement results. The defect on accuracy of this instrument, which is incompatible with extensometers, can be compensated. Overall, the main sources of error in these devices are the deformation of the load cell and that on the non-gage section of specimen. This conclusion can provide guidance on the design of other similar devices. [ABSTRACT FROM AUTHOR]

We report the realization of tin-oxide nanowires on patterned structures using a vapor–liquid–solid (VLS) process. While gold acts as the catalyst for the growth of wires, a tin-oxide containing sol–gel solution is spin coated on silicon substrate to act as the source for SnO vapor. The growth of tin-oxide nano-structures occurs mostly at the vicinity of the pre-deposited solution. By patterning the gold as the catalyst material, one is able to observe the growth at desired places. The growth of nanowires is highly dense within 100 µm away from such in situ source and their length is of the order of 5 µm. By further distancing from the source, the growth becomes more limited and nanowires become shorter and more sparsely distributed. The growth of nanowires has been studied using scanning and transmission electron microscopy tools while their composition has been investigated using XRD and EDS analyses. As a novel application, we have employed the grown nanowires as electron detection elements to measure the emitted electrons from electron sources. This configuration can be further used as electron detectors for scanning electron microscopes. [ABSTRACT FROM AUTHOR]

Tin oxide (SnO2) is one of the most promising transparent conducting oxide materials, which is widely used in thin film gas sensors. We investigate the dependence of the deposition time on structural, morphological and hydrogen gas sensing properties of SnO2 thin films synthesized by dc magnetron sputtering. The deposited samples are characterized by XRD, SEM, AFM, surface area measurements and surface profiler. Also the H2 gas sensing properties of SnO2 deposited samples are performed against a wide range of operating temperature. The XRD analysis demonstrates that the degree of crystallinity of the deposited SnO2 films strongly depends on the deposition time. SEM and AFM analyses reveal that the size of nanoparticles or agglomerates, and both average and rms surface roughness is enhanced with the increasing deposition time. Also gas sensors based on these SnO2 nanolayers show an acceptable response to hydrogen at various operating temperatures. [ABSTRACT FROM AUTHOR]

La-doped and undoped xBiInO3-(1 − x) PbTiO3 (BI-PT) thin films are deposited on (101)SrRuO3/(100)Pt/100) MgO substrates by the rf-magnetron sputtering method. The structures of the films are characterized by XRD and SEM, and the results indicate that the thin films are grown with mainly (100) oriented and columnar structures. The ferroelectricity and piezoelectricity of the BI-PT films are also measured, and the measured results illustrate that both performances are effectively improved by the La-doping with suitable concentrations. These results will open up wide potential applications of the films in electronic devices. [ABSTRACT FROM AUTHOR]

Using anodic aluminum oxide membranes as the nanoreactors and controller, oriented nanowire arrays of the diluted magnetic semiconductor Mn-doped CuO have been successfully fabricated using Mn(NO3)2 · 4H2O and Cu(NO3)2 · 3H2O as the starting materials. X-ray diffraction measurements showed that the as-prepared oriented nanowire arrays are of high purity. Scanning electron microscope and transmission electron microscope studies showed the nanowires are oriented, continuous and uniform with a diameter and length of about 170 nm and several tens of micrometers, respectively, and thus of a high aspect ratio. Low-temperature magnetic measurements showed the ferromagnetic property of the oriented Mn-doped CuO nanowire arrays with the critical temperature at around 80 K, which will endow them with great potential applications in spintronics in the future. [ABSTRACT FROM AUTHOR]

Bi2Te3 single crystals were prepared by the solid-state reaction method. The effect of the vacuum on the growth of Bi2Te3 single crystals was studied with varying the oxygen content by controlling the air pressure in the silica tube. High quality Bi2Te3 single crystals have been obtained and there is no influence on the growth by an extremely small amount of oxygen in a high vacuum at 1.0 × 10−3 Pa. As the air pressure is increased at 1.0 × 10−2 Pa, oxygen only mainly impacts on the growth of the surface for the prepared samples. Micron-sized rod-like structure and flower-like clusters are observed on the surface. For the samples prepared at 1.0 × 10−1 Pa, x-ray diffraction data show that the yellow part on the surface is Bi2TeO5, while the Bi2Te3 single crystal is still the major phase as the inside part. More interestingly, various crystal morphologies are observed by scanning electron microscope for Bi2Te3 near the boundary between Bi2Te3 and Bi2TeO5. Possible growth mechanisms for Bi2Te3 with different morphologies are discussed in detail. [ABSTRACT FROM AUTHOR]

An in situ ultrahigh-strength ductile Al50Sc50 bulk alloy is produced by the copper mold casting method with a composite microstructure of micron-/submicron-sized grains and nanoscale twins. According to the microstructural investigations, hierarchical nanotwinned lamellar AlSc bundles with embedded micron-/submicron-sized Al2Sc and AlSc2 are observed. The as-cast alloy displays a unique act of ultrahigh strength of ∼1.85 GPa together with pronounced work hardening and a large plasticity of ∼14%. Further microstructural investigations on deformed specimens indicate that abundant hierarchical nanotwinned lamellar AlSc bundles are effective to dissipate localization of shear stress or block dislocations from spreading throughout the alloy and hinder the propagation of microcracks formed by local stress transition. [ABSTRACT FROM AUTHOR]

A post-complementary metal oxide semiconductor (CMOS) compatible microfabrication process of piezoelectric cantilevers has been developed. The fabrication process is suitable for standard silicon technology and provides low-cost and high-throughput manufacturing. This work reports design, fabrication and characterization of piezoelectric cantilevers based on aluminum nitride (AlN) thin films synthesized at room temperature. The proposed microcantilever system is a sandwich structure composed of chromium (Cr) electrodes and a sputtered AlN film. The key issue for cantilever fabrication is the growth at room temperature of the AlN layer by reactive sputtering, making possible the innovative compatibility of piezoelectric MEMS devices with CMOS circuits already processed. AlN and Cr have been etched by inductively coupled plasma (ICP) dry etching using a BCl3–Cl2–Ar plasma chemistry. As part of the novelty of the post-CMOS micromachining process presented here, a silicon Si (1 0 0) wafer has been used as substrate as well as the sacrificial layer used to release the microcantilevers. In order to achieve this, the Si surface underneath the structure has been wet etched using an HNA (hydrofluoric acid + nitric acid + acetic acid) based solution. X-ray diffraction (XRD) characterization indicated the high crystalline quality of the AlN film. An atomic force microscope (AFM) has been used to determine the Cr electrode surface roughness. The morphology of the fabricated devices has been studied by scanning electron microscope (SEM). The cantilevers have been piezoelectrically actuated and their out-of-plane vibration modes were detected by vibrometry. [ABSTRACT FROM AUTHOR]

We report the preparation of Cu2SixSn1[?]xS3 thin films for thin film solar cell absorbers using the reactive magnetron co-sputtering technique. Energy dispersive spectrometer and x-ray diffraction analyses indicate that Cu2Si1[?]xSnxS3 thin films can be synthesized successfully by partly substituting Si atoms for Sn atoms in the Cu2SnS3 lattice, leading to a shrinkage of the lattice, and, accordingly, by 2th shifting to larger values. The blue shift of the Raman peak further confirms the formation of Cu2SixSn1[?]xS3. Environmental scanning electron microscope analyses reveal a polycrystalline and homogeneous morphology with a grain size of about 200-300 nm. Optical measurements indicate an optical absorption coefficient of higher than 104 cm[?]1 and an optical bandgap of 1.17+-0.01 eV. [ABSTRACT FROM AUTHOR]

A series of ex situ samples of bulk MgB2 were prepared with an addition of excess Mg up to 5% and varying sintering temperatures between 700 and 950 degC. All the samples were subjected to XRD and SEM characterization as well as thermoelectric power S(T), resistivity r(T) and magnetization M(B) measurements at 4.2 and 20 K and applied fields B = 0-8 T. Various normal and superconducting state properties show weakly coupled particles in the samples. The samples typically show high values of r(300 K) that vary between 0.12 and 254 mO cm. The critical current density Jc(4.2 K,1 T) show low values that vary between 1.8 x 107 and 1.7 x 108 A m[?]2. The temperature dependence of resistivity in the normal state scales perfectly among the samples to within a multiplication factor. Following Rowell's analysis (2003 Supercond. Sci. Technol. 16 R17), this indicates a difference in normal state connectivity, i.e. effective current-carrying cross section, AF, which is found to vary from 0.02% to 7% in different samples. Surprisingly, no correlation between the Jc and AF is found in our samples. However, Jc(B) of all the samples can be scaled within a multiplication factor at both 4.2 and 20 K until crossover fields Bcr[?]2 and 1.3 T, respectively. The Jc(B) of the samples follows a B[?]1 dependence until Bcr, at both T = 4.2 and 20 K, beyond which it decreases rapidly towards zero with increasing B. The superconducting transition measured resistively in the presence of B shows an enhanced broadening. We further attempt to delineate the role of the intra-particle and inter-particle regions in determining the Jc(B) and r(T,B) properties of our weakly coupled samples. [ABSTRACT FROM AUTHOR]