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Small size fiber optic devices integrated with chemically sensitive photonic materials are emerging as a new class of high-performance optical chemical sensor that have the potential to meet many analytical challenges in future clean energy systems and environmental management. Here, we report the integration of a proto on conducting perovskite oxide thin film with a long-period fiber grating (LPFG) device for high-temperature in situ measurement of bulk hydrogen in fossil- and biomass-derived syngas. The perovsldte-type Sr([Ce.sub.0.8][Zr.sub.0.1])[Y.sub.0.1][O.sub.2.95] (SCZY) nanocrystalline thin film is coated on the 125 [micro]m diameter LPFG by a facile polymeric precursor route. This fiber optic sensor (FOS) operates by monitoring the LPFG resonant wavelength ([[lambda].sub.R]), which is a function of the refractive index of the perovskite oxide overcoat. At high temperature, the types and population of the ionic and electronic defects in the SCZY structure depend on the surrounding hydrogen partial pressure. Thus, varying the [H.sub.2] concentration changes the SCZY film refractive index and light absorbing characteristics that in turn shifts the [[lambda].sub.R] of the LPFG. The SCZY-coated LPFG sensor has been demonstrated for bulk hydrogen measurement at 500[degrees]C for its sensitivity, stability/ reversibility, and [H.sub.2]-selectivity over other relevant small gases including CO, [CH.sub.4], [CO.sub.2], [H.sub.2]O, and [H.sub.2]S, etc.

Oriented semiconductor nanowire thin films are used to demonstrate the new concept of NW thin-film transistors (NW-TFTs). The concept opens new route to high-performance flexible macroelectronics, which might affect the existing applications as well as new generation of flexible, wearable, or disposable electronics for computing, storage, and wireless communication.

The influence of the speed of the switching process on the nonequilibrium domain structures in magnetic thin-film elements undergoing large angle rotations was studied with time-resolved scanning Kerr microscopy and numerical modelings. In particular, the systematic evolution of the spatiotemporal nature of the reversal of a small [Ni.sub.80][Fe.sub.20] element to progressively faster switching fields has been investigated. Generally, the magnetization evolves into a complex domain structure in nonequilibrium state when a magnetic element is excited by applying a short magnetic field pulse. The degree of complexity of the nonequilibrium domain structure is found to be a strong function of the speed of the switching process. Index Terms--Magnetic domains, magnetization reversal, magnetooptic Kerr effect, simulation.

This paper summarizes a theoretical study, which is a natural continuation of approximately 50 years of research in the field of acoustoelasticity. Recently, the researchers' interest has been directed towards considering compressible fluid in contact with thin walled structures as it was found that the acoustic-structural coupling significantly changes the dynamic behavior of the system. Despite the interesting findings the main results still need additional, numerical, or experimental verification. The present work is intended to cast more light on the acoustic-structure coupling of light fluid-shell systems using a numerical approach, namely 3-D finite element (FE) modeling. Two different acoustoelastic systems are considered. The first system is a thin circular cylindrical shell containing light fluid in a coaxial annular duct and the second system is a thin-walled vehicle passenger compartment interacting with the enclosed cavity. Both systems are studied using ANSYS finite element code. The modeling involved shell finite elements for the structure and 3-D acoustic elements for the cavity. The 3-D FE modal analysis used produced results visualizing the complex picture of acoustic-structure coupling. It was confirmed that (1) in both fluid-elastic systems the strongest acoustic-structural coupling exists if the resonances of uncoupled acoustic and mechanical systems are close and (2) the nature of the acoustic-structural coupling is identical in the two cases studied. However, it was found that strong coupling between the thin-walled structure and the acoustic cavity exists in the vicinity of any uncoupled acoustic resonance. Thus, the coupled properties of the systems were found to be dominated by the uncoupled acoustic resonances. As the focus of this study is on the mode shapes of vibration, it was found that coupled acoustic-structure modes of vibration exist in the neighborhood of an uncoupled acoustic resonance, which means that the coupled system manifests a specific type of energy exchange. These modes were termed coupled 'combined' modes to differentiate from the coupled component responses. It was also found that the coupled 'combined' modes are clustered around a rigid-walled cavil, mode, and any acoustic-structure resonance of a given group involves this particular uncoupled acoustic mode. In conclusion, it is shown that the acoustic-structure interaction causes the appearance of coupled 'combined' modes not existing in the shell in vacuo or rigid-walled acoustic spectrum. It was found also that the subsystems preserve their capability of independent vibration responses, i.e., the response at the component modes is believed to be strong at their uncoupled frequencies. [DOI: 10.1115/1.2345679] Keywords: acoustic-structure interaction, vibration, finite elements

A tunable third-order combline bandpass filter using thin-film barium-strontium-titanate varactors and fabricated on a sapphire substrate is reported. Application of 0-200-V bias varied the center frequency of the filter from 2.44 to 2.88 GHz (16% tuning) while achieving a 1-dB bandwidth of 400 MHz. The insertion loss varied from 5.1 dB at zero bias to 3.3 dB at full bias, while the return loss exceeded 13 dB over the range. The third-order intercept of the filter was found to be 41 dBm. Index Terms--Barium strontium titanate (BST), combline filter, ferroelectric films, intermodulation distortion, microstrip filters, resonators, thin-film devices, tunable filters, varactor.

An analytical analysis for poly-crystalline silicon thin-film transistor is presented. The Green's function approaches is adopted to solve the two-dimensional Poisson's equation using Neumann's boundary conditions at the silicon-silicon di-oxide interface. The developed model gives an insight of device behavior due to the effect of traps and also grain-boundary effect. The analysis of threshold voltage depicts short-channel effects and drain-induced barrier lowering. The model is extended to analyze the transfer characteristics and obtain the transconductance of the device. The results obtained show good agreement with the numerical model and with simulated results, thus proving the validity of our model.

Very thin (2.3-5.5 nm) self-assembled organic dielectric multilayers have been integrated into organic thin-film transistor structures to achieve sub-1-V operating characteristics. These new dielectrics are fabricated by means of layer-by-layer solution phase deposition of molecular silicon precursors, resulting in smooth, nanostructurally well defined, strongly adherent, thermally stable, virtually pinhole-free, organosiloxane thin films having exceptionally large electrical capacitances (up to [approximately equal to] 2,500 nF x [cm.sup.-2]), excellent insulating properties (leakage current densities as low as [10.sup.-9] A x [cm.sup.-2]), and single-layer dielectric constant (k) of [approximately equal to] 16. These 3D self-assembled multilayers enable organic thin-film transistor function at very low source-drain, gate, and threshold voltages ( gate insulator | molecular multilayer | organic dielectric | self-assembly

A study reports about the high mobility, n-type transparent thin-film transistors (TTFTs) with a zinc indium oxide (ZIO) channel layer. These devices is found to have excellent drain current saturation, peak incremental channel mobilities of 45-55 square-cm V(super -1)s(super -1), drain current on-to-off ratios of ~10(super 6), and inverse subthreshold slopes of ~0.8 V/decade.

Research involving above-threshold parameter extraction and modeling for amorphous silicon thin-film transistors is described and discussed.

Polycrystalline SiC on sapphire substrates is examined for use as thin-film Fabry-Perot interferometers for fiber-optic temperature measurements in harsh environments.

Mobility data for laterally crystallized poly-Si thin-film transistors (TFT) are presented and discussed.

The growth mechanism of metal induced lateral crystallization (MILC) is examined and modeled.

A procedure is proposed for obtaining identification (ID) numbers using polycrystalline silicon (poly-Si) thin-film transistors (TFT).

Shunt-assisted simultaneous quenches in series-connected resistive superconducting fault current limiter (SFCL )components are examined and discussed.

A numerical analysis of a resistive superconducting fault current limiter (SFCL) using superconducting thin film is described.

A procedure is described for fabricating uniform arrays of stacked Josephson junctions.

Changing fabrication parameters, such as the thickness and deposition rate of the Al barrier, results in junctions with?different electrical properties. ?

The effect of the top gate on the static characteristics of dual-gate hydrogenated amorphous silicon (a-Si:H) thin-film transistors (TFT) is investigated and reported.

The properties and characteristics of copper-induced polysilicon thin film transistors (TFT) are investigated and reported.

Effects of temperature variations on ZnO-based solidly mounted bulk-acoustic-wave resonators (SMR) are examined and discussed.

The presence of a space chargein a ferroelectric thin film, in the presence of Schottkey barriers at two electrode/film interfaces, are investigated. Numerical simulation, using Landau-Khalatnikov, theory, is employed.

Measurements of the static phase noise and vibration sensitivity of thin film resonator (TFR) , operating at 640 MHz and 2110 MHz, are examined. It is shown that the short-term frequency instability of the filters is small, compared with that induced in the oscillator signal by phase modulation (PM) noise.

Cylindrical polyvinylidene fluoride (PVDF) film transducers, used for transmitting and receiving of 40KHz ultrasonic waves in air, are discussed. The focus is on the transducers' omni-directional polar response.

It is shown that surface micromachined bridge resonators can be used to construct miniaturized microwave filters.

This paper provides a systematic micromagnetic analysis on the magnetization processes in various miniaturized single-turn head designs. The calculation results show that a thick yoke yields the formation of a magnetization vortex through the yoke thickness, resulting in efficient flux conduction at small yoke dimensions. A vortex structure is also important for the pole tips to maintain zero remanence after writing. Following this understanding, a hollow yoke structure has been studied to promote the efficient flux conduction in the yoke and flux closure mode in the pole tips at the remanent state. The simulation results are elucidating for efficient single-turn head designs at small yoke dimensions. Index Terms--Narrow tracks, single-turn write heads, thin film heads, write heads.

Two innovative line-crossover structures are described. They exhibit strengthened mechanical durability and reduced data-line signal delay because of a recessed air-gap line-crossover.

Anisotropy of surface acoustic wave (SAW) propagation along single crystal substrates yields efficient control of the calibration curve, sensitivity, threshold value, and resolution ability of SAW-based gas sensors. Control can be managed for a given sorbent film by changing the substrate material and its crystallographic orientation.

It is shown that 1.55-micromillimeter buried-heterostructure (BH) vertical-cavity surface-emitting lasers (VCSEL) with wafer-fused InGaAsP/In/P-GaAs/Al/As distributed Bragg reflectors can be fabricated by thin-film wafer fusion.

An investigation of the quantum yield (QY) experiment reveals that stress-induced leakage current (SILC) and QY are caused by different defects in the oxide. It is concluded that it is not correct to interpret reduction in QY after stress as a measure of energy loss of SILC electrons.

Low-frequency noise (LFN) properties of field-effect transistor s (FET) that rely on polymers as substrate materials are examined. Explanation is provided in terms of nonstationary mobility in the semiconducting polymer.

Electrical instability of amorphous thin-film transistors manifests as a shift in threshold voltage after long-time application of gate voltage. The formulation of this shift is given as a function of temperature , time, and gate voltage.

Carrier transport across a grain boundary (GB) formed by a collision of two metal-induced laterally crystallized (MILC) fronts is examined. Though the GB occupies a small part of total device volume, it significantly affects the resistance of MILC resistors and the leakage of MILC thin-film transistors.

Research into the enhancement of thin-film transistors circuits using amorphous silicon is presented. The designs provide constant output current and have potential applications in active-matrix organic light emitting displays.

The fabrication of thin-film transistors using a new hybrid process that converts amorphous silicon to polycrystalline silicon using Ni-metal-induced lateral crystallization before being improved via excimer laser annealing is described.

Research into high-performance bottom electrode organic thin-film transistors is presented.

Thin-film X-ray diffraction (XRD) and development of instrumentation for it are discussed. Topics include introduction to thin-film X-ray diffraction, what constitutes thinness in a film, polycrystalline thin-film XRD, epitaxial thin-film XRD, X-ray reflectivity, and convergence. Table lists key requirements of XRD techniques.

It has been possible to integrate amorphous and polycrystalline silicon thin-film transistors with good performance in a single film of silicon without laser processing.

Issues concerning the production of high quality films, for high frequency devices, on two inch and three inch sapphire substrates are discussed. Preparation methods for 4-pole band pass filters on double-sided two inch sapphire films are detailed.

Research into the use of GaN thin film materials as a piezoelectric devices is presented.

Organic thin film transistors of different designs were modeled.

Ac characteristics of electro-formed Cr/p+ hydrogenated amorphous silicon thin film memory devices were examined.

A new study of aluminum-induced crystallization of amorphous silicon is presented. Its uses as a low-temperature alternative to solid-phase and laser crystallization is investigated.

Hot-carrier degradation in thin-film silicon-on-insulator nMOSFET's has been studied.

Laser-processed thin-film transistors (TFTs) made from sputtered amorphous-silicon films are discussed. TFT performance is better as the hydrogen (H) content goes down. Devices made from about 0% H sputtered films perform like those made from low-pressure chemical-vapor deposition processes (LPCVD) but are made at a much lower temperature. The best sputtered TFTs had on/off current ratios of (10 to the 8th)+.

A study investigated the properties of three-terminal, three-color a-SiC:H/a-Si:H-based TCO/PINIP/TCO/PIN/metal detector assemblies with a focus on the optical and transient behavior organization. Different TCO/PINIP/TCO/PIN/metal detector assemblies featuring different TCO surface properties were compared in terms of steady-state properties, advantages and disadvantages. Experimental methodology, results and conclusions are discussed.

The effect of a gate-all-around thin-film transistor (GAT) with a lightly doped drain structure on the reduction of the off-current is studied. The off-current of the GAT is found to be almost the same as that of a single-gate TFT with an LDD structure although the GAT's channel area is about twice as big as that of the SGT. The suppression mechanism of the individual performance variations in the GAT is also investigated by thinning the channel poly-Si.

A study on Cu(In,Ga)Se2-based polycrystalline thin film solar cells presents a comprehensive picture of chemical oxygenation effects and their consequences for the electronic properties of such Cu(In,Ga)Se2-based solar cells. Two distinct effects of air annealing of the absorber surface were observed: first, oxygenation leads to passivation of surface defects both at the grain boundaries and at the free surface of the Cu(In,Ga)Se2 film. Second, air annealing at 200 degrees C leads to a decrease in CU concentration at the absorber surface, which ultimately results in a decrease of space charge density within the absorber.