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The article studies the current-voltage mechanism of low-ideality factor ZnO Schottky diodes over temperature range of 40-423 K. Findings revealed that TE was a major current transport mechanism at RT and above.

A study was conducted to examine the above-threshold characteristics of amorphous silicon Zn-based oxide (ZnO) thin-film transistors (TFTs) using exponential tail-state distribution model. Findings suggested that an exponential tail-state distribution model could be used to explain the above-threshold behavior of ZnO TFTs.

A study was conducted to compare the mutual interactions amongst the top-and bottom-gate fields in a dual-gate structure for amorphous InGaZn[O.sub.4] (a-IGZO) and hydrogenated amorphous silicon thin-film transistors (TFTs). Findings conclude the limited penetration of band bending into the a-Si:H layer.

Zinc-oxide-based thin-film bulk acoustic wave (BAW) resonators are examined with respect to variation of dimensions of a boundary frame spurious mode suppression structure. The simple semi-2-D plate model has predicted the device behavior, the 2-D finite element method results have coincided with them with some additional effects and breaking the resonator behavior down to eigenmodes have provided insights into the physics of the device operation.

Constant-voltage-bias stress measurements are conducted on thin-film transistors (TFTs) with amorphous indium-gallium-zinc-oxide (IGZO) channel layers prepared by using radio frequency (RF) sputtering using a postdeposition annealing temperature. The instability and hysteresis observations are found to be consistent with a Si[O.sub.2]/IGZO TFT instability mechanism involving electron trapping within the IGZO channel layer.

Lightning arresters provide protection for transmission lines and power equipments. During the occurrence of lightning or switching surges, a voltage level above the equipment insulation level can be reached. An arrester, properly working, is able to limit this voltage level avoiding damages to the protected equipment. A defective arrester may not be able to provide the proper protection level in substations, exposing the equipment and personnel to damage. Monitoring of surge arresters is usually conducted by means of current measurement or thermal images acquisition. But, among power companies, there is no model procedure for the monitoring conduction and analysis of the obtained results. Besides that, when some abnormality is detected, the arrester is replaced by a new one and no further study is conducted to evaluate what kind of problem happened to it. This work proposes a method for analysis of ZnO arresters by the study of failures and usage of artificial neural networks-ANN. The ANN is able to analyze the thermal profile, detect and classify patterns that could be undetected by a visual analysis. Index Terms--Arresters, artificial neural networks, power system monitoring, thermograph, zinc oxide.

The performance of resistance random access memory (RRAM) devices based on spin-coated sol-gel-derived zinc oxide (ZnO) thin films is examined. The devices are fabricated on a flexible plastic substrate and have displayed excellent durability upon repeated bending tests, thus showing their potential for flexible low-cost memory devices.

A combinatorial RF sputtering technique is used to fabricate thin-film transistors by using a semiconductor of the form [(ZnO).sub.x] [([In.sub.2][O.sub.3]).sub.1-x]. The devices fabricated with a zinc oxide fraction of 0.67 (plusminus) 0.02 have displayed the highest mobilities of 35 [cm.sup.2]/V * s for 300 degree Celsius annealing conditions.

The propagation characteristics of the shear horizontal surface acoustic wave (SH-SAW) in ZnO textured ZnO films are described. The SH-SAW device consisting of ZnO film could find potential use as candidate for a liquid sensor that detects changes in the electrical conductivity and relative permittivity.

Silicon nitride films of different refractive indices are used to study the effect of hydrogenation of ZnO TFTs by plasma-deposited silicon nitride gate dielectric. Secondary ion mass spectroscopy study show that in ZnO TFT using high refractive index silicon nitride, gate dielectric is higher that TFTs with low-refractive index silicon nitride, which is indicative of the hydrogenation of ZnO TFTs by high refractive index silicon nitride gate dielectric.

The performance of zinc-oxide (ZnO) elements is strongly dependent on the properties of the boundaries between ZnO grains, which are greatly affected by the formation of spinel particles between ZnO grains during the sintering process. The authors studied the effects of reducing spinel particles on the performance of elements and found that the characteristics of the spinel-reduced elements were improved compared with that of normal elements (e.g., superior voltage-current characteristics, smaller micropores, and larger capacitance). It was also found that the sintering temperature of the spinel-reduced elements could be decreased by more than 100[degrees]C than that of normal elements. Index Terms--Arresters, energy absorption capability, protective characteristic, zinc-oxide (ZnO) elements.

Superconducting Fault Current Limiters (SCFCLs) have improved the reliability and stability of power systems, which consists of a transformer type inductive SCFCL with a ZnO device and a resistor in parallel. The contribution share of the voltage drop suppression and the acceleration energy consumption to the improvement of the power system stability are clarified with conditions like generator output and fault clearing time.

A comparative study of the performance and stability of the zinc oxide (ZnO) thin-film transistors (TFTs) and silicon dioxide and nitride as the gate insulators is presented. The devices with SiN dielectric are shown to perform better than the devices containing silicon dioxide.

A standard ion-exchange technique was used for the fabrication of channel optical waveguides in novel Er-doped and Er-Yb co-doped ZnO-containing silicate glasses. Findings reveal the simulation of very large net optical gain for an ideal overlap of the pump and signal optical field in a glass containing at 3% of Er and no Yb.

dc conductivity and ac impedance measurements were made in air and in vacuum on samples of low density polyethylene to which nano-sized and micro-sized ZnO particles and a dispersant had been added. The samples were 150-200 [micro]m thick. The temperature range was 30-70 [degrees]C. The temperature dependence of the vacuum dc conductivity in samples containing the dispersant and 10% w/w nanosized ZnO followed an Arrhenius relationship closely, the conductivity being 1-2 orders of magnitude lower than that of a sample containing dispersant only. The addition of 10% w/w microsized ZnO had very little effect on the dc conductivity. The ac measurements were made in the frequency range 10 mHz--1 MHz. Addition of nanoparticles increased the ac conductivity at higher frequencies but decreased it at lower frequencies, the cross-over frequency increasing with increasing temperature. The real part of the relative permittivity of samples with nanoparticles was increased relative to that of samples containing dispersant only, at all temperatures, but the corresponding values in samples with microparticles were unchanged, within experimental error. Space charge profiles were obtained using the laser-intensity-modulation-method (LIMM). Space charge densities of order 300 [Cm.sup.-3] were measured in the bulk near the electrodes, several hours after poling at field strengths around 30 kV/mm. Index Terms--dc conductivity, ac impedance, space charge profiles, nanosized ZnO, microsized ZnO.

The energy absorption capability is a key parameter for ZnO varistors. This paper discusses the nonuniformity of energy absorption capabilities of ZnO varistors. With experiment results, we show that energy absorption capabilities of ZnO varistors can be highly scattered, for different commercial varistors, and for the same varistors under diverse current waves. We explain this nonuniformity phenomenon through numerical simulations, based on the microscopic circuit and heat transfer models of ZnO varistors. How the applied current, the nonuniformity of microstructure, and the nonuniformity of microstructural electrical and thermophysical characteristics influence the energy absorption capabilities of ZnO varistors is also analyzed. Index Terms--Current concentration, energy absorption capability, impulse current, nonuniformity, ZnO varistor.

A chemical bath deposition process for zinc oxide (ZnO) deposition is used for demonstration of solution-processed transparent ZnO transistors. The process results in high mobility of 3.5 [cm.sub.2]/V.s with on-off ratios of approximately [10.sup.5].

The experimental results on transition metal doping of ZnO is reviewed and the material that can be made with a single phase at high levels of Co incorporation is shown. Solutions involve either cubic phase ZnO or the use of additional stressor layers to create a larger spin splitting in order to get a polarized light emission.

Textured ZnO films that were fabricated with a high electromechanical coupling coefficient k(sub 15) are discussed. Experiments have showed that the film has a lot of potential for use in shear-mode FBAR and SH-type SAW devices.

Electromagnetic emission at the very high frequency (VHF) range of 30 to 300 MHz is used to detect surface defects on outdoor polymer zinc oxide (ZnO) surge arrestors. The partial discharge related signals are recorded and studied. Since the surge arrestors are usually exposed to adverse weather conditions, the effect of moisture and pollution on the characteristics is also investigated. Samples subjected to surface pollution were created according to the IEC standard under both wet and dry conditions. The collected electromagnetic signals were sampled and analyzed using a joint time-frequency analysis tool called the Wigner-Ville distribution (WVD). The results of this work indicate that the WVD analysis can be used as a diagnostic tool for polymer ZnO surge arrestors. Index Terms--Surge arrestor, surface pollution, electromagnetic pulse, Wigner distributions.

The 500-kV polymeric ZnO surge arresters for compact transmission line against lightning overvoltage were developed and have been put into operation, which consists of arrester unit and series gap. The design of the arrester unit, including structure design, selection of ZnO varistor, parameter determination, polymeric housing design, and mechanical structure design was discussed. The design of the series gap and the determination of the series gap length were presented. The calculated results state the line surge arrester can highly improve the lightning withstand level of the compact transmission line, and the line surge arrester can withstand the effects of lightning. Index Terms--Compact transmission line, lightning protection, lightning withstand level, line surge arrester, series gap.

The fabrication and characterization of ZnO piezoelectric thin films in which the crystallite c-axis is unidirectionally aligned in the plane and the films are deposited by a conventional radio frequency (RF) magnetron sputtering apparatus without epitaxy is reported. Measurement of the reflection coefficient S11 of the ZnO film/glass substrate composite shear mode resonator and confirmed that the resonator excites shear wave only in the very high frequency to ultra high frequency ranges.

High quality (Q), freestanding, narrow beam supported film acoustic-wave resonators (FBARs) fabricated with silicon micromachining is described. The Al/ZnO/Al type FBAR is preferred to the Al/ZnO/Al/Si(sub x)N(sub y) type for wide bandwidth filters as the former type has larger electromechanical coupling constant and high Q factor.