Electrical Property Test Research Articles

Resistive Switching Behavior of Hafnium Oxide Thin Film Grown by Magnetron Sputtering

Abstract The HfO2 thin films with resistive switching behaviors were grown on indium tin oxide (ITO) /Glass substrates by radio-frequency (RF) magnetron sputtering method. The results of electrical tests indicate that HfO2 thin films show a bipolar resistive switching behavior. Using Ti as a buffer layer on the cathodal side of the memory cell, relatively reliable endurance (>2×102 cycles at 20 °C) and long data retention time (>104s at 20 °C) have been demonstrated, and the high-resistance to low-resistance ratio can reach 104. Based on the electrical property test results, the phenomena can be correlated with oxygen-vacancy-related traps. Space charge limited current (SCLC) mechanism is believed to be the reason for the resistive switching from the OFF state to the ON state.

Aqueous solution synthesis of reduced graphene oxide-germanium nanoparticles and their electrical property testing

Aqueous solution synthesis of reduced graphene oxide-germanium nanoparticles (RGO-GeNPs) was developed using graphene oxide (GO) as stabilizer, which could be conducive to obtain better excellent electrical properties. The information about morphology and chemical composition of the nanomaterials were obtained by TEM, FTIR, EDS, and XRD measurements. Stable aqueous dispersibility of RGO-GeNPs was further improved by poly(sodium 4-styrenesulfonate) (PSS) to obtain amphiphilic polymer-coated RGO-GeNPs (PSS-RGO-GeNPs). A possible mechanism to interpret the formation of RGO-GeNPs was proposed. The as-synthesized RGO-GeNPs showed excellent battery performance when used as an anode material for Li ion batteries. The resulting nanocomposites exhibited high specific capacity and good cycling stability after 80 cycles. This study showed a facile strategy to synthetize graphene and Ge nanocomposites which can be a hopeful anode material with excellent electrical properties for lithium ion batteries.

Preparation and properties of alkaline functionalized carbon nanotubes reinforced polyurethane composites

Composites consisting of polyurethane (PU)/carbon nanotubes (CNTs) have been successfully prepared by solution mixing method. CNTs were modified through mechano-chemical reaction to increase the compatibility with PU via hydrogen bondings. SEM microphotographs proved that modified CNTs (M-CNTs) became shorter and FTIR spectra showed that hydroxyl groups had been introduced to the surface of M-CNTs. SEM images of PU/M-CNTs composites also proved that M-CNTs were effectively dispersed in PU matrix. Mechanical property tests showed that addition of M-CNTs could significantly improve the tensile properties of PU/M-CNTs composite (breaking strength enhancement ratio for composite with 5.0 wt% M-CNTs was 103.81 %). The thermal stability of composites with M-CNTs was also improved. The initial degradation temperature enhancement was 19.9 oC for the composite with 0.5 wt% M-CNTs. Electrical property tests showed that the electrical properties were improved by adding M-CNTs. The volume conductivities increased 3 and 5 orders of magnitude for the composites with 5.0 wt% and 10 wt% M-CNTs, respectively. The addition of M-CNTs had little effect on the elastic properties of the composites.

Synthesis and Characterization of Tetraaniline-Polyethylene Glycol Block and Star-shaped Copolymers

In this paper, three block or star-shaped tetraaniline-polyethylene glycol copolymers were obtained using a series of methylbenzenesulfonyl chloride homologous compounds as intermediates. To achieve this goal, firstly, tetraaniline was synthesised by 4-aminodiphenyamine through redox reaction in an acidic acetone solution; tetraaniline was then reacted with 4-toluene sulfonyl chloride, 2,5-dimethylbenzenesulfonyl chloride and 2-mesitylenesulfonyl chloride, respectively, to give a series of sulfamide intermediate products with different amounts of capped methyl groups on the benzene ring. These sulfamide intermediate products were oxidized by potassium permanganate, to turn the capped methyl groups equally into carboxyl groups. At last, methoxy polyethylene glycol (PEG) was reacted with these carboxyl groups through esterification reaction to give the tetraaniline-polyethylene glycol copolymers, in which the number of PEG chains was determined by the number of methyl groups on the intermediate products mentioned above. Structure characterization of all related products within the routes, as well as electrical chemical property test of tetraaniline and final products, was carried out using FT-IR, H NMR, UV-Vis, GPC and electrochemical workstation. The results of structure characterization suggested that ideal products were synthesized successfully through designed routes, the cyclic voltammogram and conductivity data suggested that the electrical chemical property of these copolymers was similar with that of tetraaniline, possessing the typical change of oxidation-reduction states. As polyaniline is a typical electrochromism material, whose electrochromism capability is majorly succeeded by tetraaniline, these copolymers could be used in an electrochromism device, in which tetraaniline acts as electrochromism material, while polyethylene glycol acts as ion conducting material. Compared with electrochromism devices formed by polyaniline and polyethylene glycol separately, the ones formed by these copolymers would be much more compatible and processible. Furthermore, the micro structure of an electrochromism device could be formed through copolymers' self-assembly, and the micro phase morphology of the structure could be modified by adjusting the molecular weight of each segment, as well as the number of polyethylene glycol chains.

Synthesis and characterization of multiwalled carbon nanotube/polyurethane composites via surface modification multiwalled carbon nanotubes using silane coupling agent

AbstractWell‐dispersed multiwalled carbon nanotubes/polyurethane (MWCNTs/PU) composites were synthesized in situ polymerization based on treating MWCNTs with nitric acid and silane coupling agent. The morphology and degree of dispersion of the MWCNTs were studied using a high resolution transmission electron microscopy (HR‐TEM) and X‐ray powder diffraction (XRD). The result showed that MWCNTs could be dispersed still in the PU matrix well with the addition of 2 wt% MWCNTs. The thermal and mechanical properties of the composites were characterized by dynamic mechanical thermal analysis, thermogravimetric analysis, tensile, and impact testing. The result suggested that the glass transition temperature (Tg) of composites increased greatly with increasing MWCNTs content slightly, and the MWCNTs is also helpful to improve mechanical properties of composites. Furthermore, the composites have an excellent mechanical property with the addition of 0.5 wt% MWCNTs. The electrical property testing indicates that the MWCNTs can improve evidently the electrical properties of composites when adding 1 wt% MWCNTs to the PU matrix. The volume resistivity of composites reaches to an equilibrium value. POLYM. COMPOS., 33:1866–1873, 2012. © 2012 Society of Plastics Engineers

Synthesis of new unsymmetrical diamine and polyimides: structure–property relationship and applications of polyimides

A novel unsymmetrical diamine monomer 4-(2-(4-(4-aminophenoxy)phenyl)propan-2-yl)benzenamine (APPBA) containing –O– and –C(CH3)– groups was synthesized from 2-(4-aminophenyl)-2-(4-hydroxyphenyl)propane and 4-nitrofluorobenzene by the nucleophilic substitution reaction followed by catalytic reduction. Polycondensation of this diamine with aromatic dianhydrides through thermal solution imidization techniques afford a series of novel processable polyimides (PI). The structure of the monomer and polyimides were confirmed by FT-IR and 1H-NMR. The polyimides were characterized by XRD, TGA, DSC, electrical property, solution viscosity and solubility test. These polyimides had inherent viscosities in the range 0.48–0.61 dL/g. The X-ray diffraction measurements indicated that all these polyimides were amorphous. The polyimides exhibited excellent solubility in most of the organic solvents. The glass transition temperature (Tg) was observed in the range 242–282 °C. The polyimides displayed good thermal stability and the temperatures at which 10 % weight loss occurred in the range 475–504 °C. The dielectric constant of PIs was in the range of 2.82–3.55.

Investigation on Electrical Performance of Tubular Cathode for Direct Ethanol Fuel Cell

A new tubular cathode support for Direct Ethanol Fuel Cell (DEFC) was prepared by the gelcasting process using mesocarbon microbead(MCMB) and graphite as the main raw materials. Through the tubular cathode electrical property test, the advantages and disadvantages of cathode tube performance are studied at different graphite proportion. The results showed that when the graphite is more than 30 percent, the charge transmission ability has become extremely close. When the graphite ratio is 40 and 50 percent, the electrical performance is the best. With the graphite doping ratio of 40 percent, the electrode electrochemical reaction will have been reinforced when the temperature is high. When the air flow is 100 ml/min, the electricity capacity is better.

Electrical Properties Analysis and Test Result of Windings for a Fully Superconducting 10 HP Homopolar Motor

This paper describes the electrical analysis and performance test result of windings of a 10 HP homopolar fully superconducting synchronous motor. The homopolar motor has high temperature superconducting (HTS) armature and field coils. The stationary field coils make the cooling system simple and easy because there is no cryo-moving part. The design of the motor and the analysis of magnetization loss generated in the superconducting armature windings are performed by finite element method. The critical current test results of the 2G superconducting wire, the pancake coil for field winding and the race track coil for armature winding are reported.

Experimental Analysis of a Pyrotechnic Compositions Battery

A type of pyrotechnic compositions battery was developed to meet the requirements of a subminiature and fastactivated reservoir battery which would be applied to shell fuze. This battery was activated by the pyrotechnic compositions contained in the electrodes. Once the ignition impulse worked, the pyrotechnic compositions took fire immediately and melted the electrolyte. Then the rest pyrotechnic compositions served as anode and cathode. The battery began to discharge. Electrical property tests taken on the prototype cells indicated that the performance of the pyrotechnic compositions batteries were improved greatly compared with common fuze batteries. Such property parameters contained volume, activation time and energy density.

Preparation and Characterization of Nd-Doped Ti/SnO<sub>2</sub>-Sb<sub>2</sub>O<sub>5</sub> Electro-Catalytic Electrodes Used for Reactive Brilliant Red X-3B Wastewater Treatment

The best catalytic capacity of Nd-doped Ti/SnO2-Sb2O5 electrodes was obtained by sol-gel preparation. Nd-doped Ti/SnO2-Sb2O5 coating was characterized using technique such as scanning electron microscopy (SEM), and X-ray diffraction (XRD). Nd-doped electrode fragments looks smaller, more compact and more uniform than undoped electrode through SEM. The crystal cell’s average diameter of Nd-doped electrodes was 3.48nm through XRD. BOD5/COD of Reactive Brilliant Red X-3B increased 200% under optimum conditions after 1h electrolysis. Instantaneous current efficiency (ICE) was 51.15 % in first 40 min, 35.73 % in first 60 min. In the first 40 minutes of electrolysis process, COD of Reactive Brilliant Red X-3B changes conformed to the pseudo first-order kinetic equation. Electrical Properties Tests showed that the oxygen evolution potential values of Nd-doped electrodes were higher than the undoped electrodes in various media.

Effect of Graphite Dopant on the Performance of Tubular Cathode for Direct Ethanol Fuel Cell

By using the mesocarbon microbead (MCMB) and graphite as raw material, the tubular cathode green bodies of a direct ethanol fuel cell（DEFC）are shaped by the gelcasting technology and the tubular cathode is prepared by spraying the diffusion layer and the Pt/C catalyst layer after the sintering process. Through the tubular cathode physical performance and electrical property test, the advantages and disadvantages of cathode tube performance are studied at different graphite proportion. The results showed that with the increase of graphite, the ratio porosity of cathode tube support body increases at first and then decreases. However, the density has a converse trend. While the maximum porosity of the cathode tube is more than 0.5 and the corresponding density is 0.95g/cm3. Strength test showed that the cathode tube strength is better with the graphite ratio from 0 to 40 percent and can meet the actual needs. Electrical property tests showed that the cathode tube has higher current density with the graphite ratio of 40 and 50 percent.

Microwave Radar for Non-Destructive Express Testing of Electrical Properties of Semiconductor Materials

Modern technologies allow producing various semiconductor materials with unique parameters and their electrical properties should be constantly tested to provide high quality of electronic devices. Therefore testing of electrical properties of semiconductor materials is very topical subject due to practical importance and it was developed in the same pace as electronics to guarantee technical support of fundamental investigations in semiconductor physics and technology. Main electrical properties of semiconductor materials can be characterized by values of concentration and mobility of free charge carriers. In variety of measuring methods non-destructive methods have evident advantage because provide high productivity and do not require additional contacts or surface processing of tested specimens [1]. When magnetoplasmic waves were discovered it has become natural to use them for measurements of electrical properties of semiconductors because dierently to ordinary electromagnetic waves magnetoplasmic waves can propagate inside of the conductive area placed in external magnetic field and wave dispersion depends on its electrical properties [2]. There are two common methods mainly used for microwave magnetoplasmic investigations in semiconductors. One of them is based on magnetoreflection and another one is based on magnetotransmission phenomena. In case of finite thickness of the specimen the dependence of magnetoreflection and magnetotransmission on magnetic field has a resonant character. Measuring oscillation

Preparation and characterization of carbon nanotube network via a filtration method

The single carbon nanotube (CNT) has lots of important potential applications in many fields for its good electrical conductivity and mechanical property. But, single CNT is a nanometer material, and a powder from the macro point of view, which would hinder its applications. So there is need to CNT macro material. There are two ways to make the lots of single CNTs into macro materials: adding adhesive and without adhesive by other methods. Of course, adding adhesive can result in impurity. So the method without adhesive is a better way. But the way has no connections between the single CNTs and can result in that the obtained macro materials electrical conductivity and mechanical property are not as good as that of the single CNT. In order to resolve the problem, the authors firstly made the single CNTs into a macro material (CNT network precursor) via filtration method, and then grew new CNT between the close pristine single CNTs. The obtained macro material can have much better (ten times) electrical conductivity and mechanical property than those of the CNT network precursor. The obtained material and the CNT network precursor were both characterized by SEM, electrical conductivity testing and mechanical property testing.

Nanoscale Testing of Specialized Polymers and Components used in Non Impact Printing

Nanoscale testing is a growing field applied across many disciplines, sciences and industries. Recently nanoscale testing of polymers used in the printing industry has been shown to supplement conventional testing of physical, dynamic and electrical properties. Nanoscale testing consists of a variety of nano testing methods that can be applied across the Non Impact Printing Industry, from material development and characterization to understanding functionality and failure modes of components. Nanoindentation, nanoscratch, nano dynamic mechanical analysis, nano modulus mapping, nano hardness, nano tensile strength and nano electrical conductivity can be measured and applied to analysis of polymer performance.This paper will describe nanoscale testing as applied to the characterization of polymers used in fusing and charge transfer applications, as well as nano testing of toner particles and fixation to print media. In addition, nanoscale testing of surface substrates, and adhesion to substrates is discussed as may be applied to ink jet technologies, thin films, and the non impact printing of electronics, biological and pharmaceutical materials.

A novel one-step electrodeposition to prepare single-phase CuInS 2 thin films for solar cells

Copper indium disulfide (CuInS 2) thin films have been successfully prepared on Ni substrates using a novel one-step potentiostatic electrodeposition combined with a potassium hydrogen phthalate (C 8H 5KO 4) complexing agent, accompanied by annealing at 350 °C. Electrodeposition in the solution of Cu and In salts and sodium thiosulfate (Na 2S 2O 3) containing an adequate concentration of C 8H 5KO 4 (e.g., [C 8H 5KO 4]=23 mM) provides thin films comprised of a CuInS 2 single phase as the bulk composition, without forming Cu x S secondary phases. In addition to the effect on bulk-phase compositions, the adjustment of [C 8H 5KO 4] causes variation in morphology and atomic composition of the film surface. The surface states of the films change from the Cu-rich rough surface at low [C 8H 5KO 4] (15 mM) to the In-rich smooth surface at high [C 8H 5KO 4] (23 mM). The higher [C 8H 5KO 4] induces the grains constructing the film to interconnect and form a densely packed CuInS 2 film without voids and pinholes. The single-phase and void-free CuInS 2 film shows a band gap of 1.54 eV, satisfying the requirement of the absorber layers in solar cells. The electrical properties tests denote its n-type conductivity with a resistivity of 9.6×10 −5 Ω cm, a carrier concentration of 2.9×10 21 cm −3 and a carrier mobility of 22.2 cm 2 V −1 s −1.

Hopping conductivity of metal-dielectric nanocomposites produced by means of magnetron sputtering with the application of oxygen and argon ions

Testing of electrical properties of nanocomposites (Co 0,45Fe 0,45Zr 0,1) x + (Al 2O 3) 1+ x within the concentration range of 0.30 < x < 0.65, produced by means of magnetron sputtering of a target composed of stripes of metallic alloy and dielectric, has been carried out. It has been found that the studied materials contain metallic nanoparticles of a diameter ranging from 6 to 10 nm. Alternating current conduction at x < 0.50 is realized by hopping mechanism while at x > 0.50 metallic conductivity is observed. The obtained results have been analyzed using a model of hopping conductivity in the egime developed earlier. This analysis allowed to extract dependences of activation energy Δ E τ and times τ in a hopping regime after isochronous (15 min) thermal annealings within the range from 293 K to 673 K.

Deoxidation of tantalum with liquid calcium

A study has been made of the feasibility of deoxidizing solid tantalum with liquid calcium. The rate of deoxidation of 0.5 cm diameter tantalum rods was measured. As an example, the oxygen content was reduced from 1765 ppm to 100 ppm in 22 hr at 1000°C. The probable rate controlling step is the diffusion of oxygen in tantalum. In extending the study to the deoxidation of sintered and anodized tantalum powder, it was found that the oxygen content could be reduced from 6600 ppm to approximately 300 ppm in a few hours at 1000°C. Capacitors were made from powders deoxidized in calcium without difficulty. The results of electrical property tests on these capacitors are very encouraging.