Study of internal oxidation kinetics of molybdenum base alloys

International Nuclear Information System (INIS)

Krushinskij, Yu.Yu.; Belyakov, B.G.; Belomyttsev, M.Yu.

1989-01-01

Metallographic and microdurometric method as well as new technique were used to study kinetics of internal oxidation (IO). It is shown that study of IO kinetics on the base of metallographic measurements of layers depth is not correct because it is related with insufficient sensitivity of the method. IO kinetics under conditions of formation of molybdenum oxide layer on saturated material surface as well as IO of alloy with high carbon content were investigated. Oxide film formation does not affect the IO kinetics; decarburization observed along with oxidation increases the apparent activation energy and K exponent on time dependence of diffusion layer depth

Decomposition of oxidezed lead and aluminium thin films on molybdenum substrates

International Nuclear Information System (INIS)

Makarovskij, N.A.

1981-01-01

The decomposition of oxidized solid phase lead and aluminium thin films on molybdenum substrates in the process of diffusion annealing in the 5x10 -5 mm Hg vacuum at temperatures from 280 to 320 deg C and from 500 to 560 deg C, respectively, is investigated. The conclusion is made that failure of oxidized lead and aluminium thin film coatings is carried out by the mechanism of volumetric self-diffusion. Experimentally established values of activation energies of the process of lead (Qsub(Mo)sup(Pb)=29 kcal/mol) and aluminium (Qsub(Mo)sup(Al)=35 kcal/mol) film failure are close to corresponding activation energies of lead and aluminium volumetric self-diffusion, which agrees with the conclusions made [ru

Mechanical properties of molybdenum coated with titanium carbide film

International Nuclear Information System (INIS)

Shikama, T.; Shinno, H.; Fukutomi, M.; Fujitsuka, M.; Okada, M.

1983-01-01

TiC-coated molybdenum is mechanically tensile tested. The 6 μm thick TiC-coated molybdenum has a higher 0.2% proof strength with a slight decrease in uniform and rupture elongation than the uncoated one. This strengthening effect of the TiC coating can be explained by the constrained effect of the high strength TiC film. The 1.2 μm thick TiC-coated molybdenum starts its plastic deformation at a lower stress than the uncoated one. Also, the coating makes the stress-strain curve more smooth. These effects are attributed to the surface effect, namely, that the interface between the molybdenum substrate and the strong and brittle TiC film acts as a strong dislocation source. The compressive stress in the TiC film will also help the start of plastic deformation at lower external stresses. (author)

Evaluation of oxide dispersion strengthened (ODS) molybdenum and molybdenum-rhenium alloys

International Nuclear Information System (INIS)

Mueller, A.J.; Bianco, R.; Buckman, R.W. Jr.

1999-01-01

Oxide dispersion strengthened (ODS) molybdenum alloys being developed for high temperature applications possess excellent high temperature strength and creep resistance. In addition they exhibit a ductile-to-brittle transition temperature (DBIT) in the worked and stress-relieved condition under longitudinal tensile load well below room temperature. However, in the recrystallized condition, the DBTT maybe near or above room temperature, depending on the volume fraction of oxide dispersion and the amount of prior work. Dilute rhenium additions (7 and 14 wt.%) to ODS molybdenum were evaluated to determine their effect on low temperature ductility. The addition of 7 wt.% rhenium to the ODS molybdenum did not significantly enhance the mechanical properties. However, the addition of 14 wt.% rhenium to the ODS molybdenum resulted in a DBTT well below room temperature in both the stress-relieved and recrystallized condition. Additionally, the tensile strength of ODS Mo-14Re is greater than the base ODS molybdenum at 1,000 to 1,250 C

Activity of molybdenum-containing oxide catalysts in the reaction of ethane oxidation

International Nuclear Information System (INIS)

Konovalov, V.I.; Ehpova, T.I.; Shchukin, V.P.; Averbukh, A.Ya.

1977-01-01

Investigation results concerning the catalytic activity of molybdenum-containing catalysts in ethane oxidation reaction are presented. It has been found that the greatest activity in the temperature range from 450 to 600 deg C is exhibited by cobalt-molybdenum catalyst; at 600 deg C bismuth-molybdenum catalyst is the most active. Nickel-molybdenum catalyst is selective and active with respect to ethylene. Iron- and manganese-molybdenum catalysts do not show high ethane oxidation rates and their selectivity is insignificant

Nitrogen incorporation in sputter deposited molybdenum nitride thin films

Energy Technology Data Exchange (ETDEWEB)

Stöber, Laura, E-mail: laura.stoeber@tuwien.ac.at; Patocka, Florian, E-mail: florian.patocka@tuwien.ac.at; Schneider, Michael, E-mail: michael.schneider@tuwien.ac.at; Schmid, Ulrich, E-mail: ulrich.e366.schmid@tuwien.ac.at [Institute of Sensor and Actuator Systems, TU Wien, Gußhausstraße 27-29, A-1040 Vienna (Austria); Konrath, Jens Peter, E-mail: jenspeter.konrath@infineon.com; Haberl, Verena, E-mail: verena.haberl@infineon.com [Infineon Technologies Austria AG, Siemensstraße 2, 9500 Villach (Austria)

2016-03-15

In this paper, the authors report on the high temperature performance of sputter deposited molybdenum (Mo) and molybdenum nitride (Mo{sub 2}N) thin films. Various argon and nitrogen gas compositions are applied for thin film synthetization, and the amount of nitrogen incorporation is determined by Auger measurements. Furthermore, effusion measurements identifying the binding conditions of the nitrogen in the thin film are performed up to 1000 °C. These results are in excellent agreement with film stress and scanning electron microscope analyses, both indicating stable film properties up to annealing temperatures of 500 °C.

Mechanism of anodic oxidation of molybdenum and tungsten in nitrate-nitrite melts

International Nuclear Information System (INIS)

Yurkinskij, V.P.; Firsova, E.G.; Morachevskij, A.G.

1987-01-01

The mechanism of anode oxidation of tungsten and molybdenum in NaNO 3 -KNO 3 (50 mass %) nitrate-nitrite melts with NaNO 2 -KNO 2 (0.5-50 mass %) addition and in NaNO 2 -KNO 2 (35 mole %) nitrite melt in the 516-580 K temperature range is studied. It is supposed that the process of anode dissloving of the mentioned metals in nitrite melt and nitrate-nitrite mixtures is two-electron. Formation of oxide passivating film is possible under electrolysis on the anode surface, the film is then dissolved in nitrate-nitrite melt with formation of molybdates or tungstates

Room-temperature solution synthesis of Ag nanoparticle functionalized molybdenum oxide nanowires and their catalytic applications.

Science.gov (United States)

Dong, Wenjun; Huang, Huandi; Zhu, Yanjun; Li, Xiaoyun; Wang, Xuebin; Li, Chaorong; Chen, Benyong; Wang, Ge; Shi, Zhan

2012-10-26

A simple chemical solution route for the synthesis of large-scale high-quality Ag nanoparticle functionalized molybdenum oxide nanowire at room temperature has been developed. In the synthesis, the protonated amine was intercalated into the molybdenum bronze layers to reduce the electrostatic force of the lamellar structures, and then the Ag nanoparticle functionalized long nanowires could be easily induced by a redox reaction between a molybdenum oxide-amine intermediate and Ag(+) at room temperature. The intercalation lamellar structures improved the nucleation and growth of the Ag nanoparticles, with the result that uniform Ag nanoparticles occurred on the surface of the MoO(3) nanowire. In this way Ag nanoparticles with average sizes of around 6 nm, and high-purity nanowires with mean diameter of around 50 nm and with typical lengths of several tens to hundreds of micrometers were produced. The heteronanostructured nanowires were intricately and inseparably connected to each other with hydrogen bonds and/or bridge oxygen atoms and packed together, forming a paper-like porous network film. The Ag-MoO(3) nanowire film performs a promoted catalytic property for the epoxidation of cis-cyclooctene, and the heteronanostructured nanowire film sensor shows excellent sensing performance to hydrogen and oxygen at room temperature.

The Structure and Stability of Molybdenum Ditelluride Thin Films

Directory of Open Access Journals (Sweden)

Zhouling Wang

2014-01-01

Full Text Available Molybdenum-tellurium alloy thin films were fabricated by electron beam evaporation and the films were annealed in different conditions in N2 ambient. The hexagonal molybdenum ditelluride thin films with well crystallization annealed at 470°C or higher were obtained by solid state reactions. Thermal stability measurements indicate the formation of MoTe2 took place at about 350°C, and a subtle weight-loss was in the range between 30°C and 500°C. The evolution of the chemistry for Mo-Te thin films was performed to investigate the growth of the MoTe2 thin films free of any secondary phase. And the effect of other postdeposition treatments on the film characteristics was also investigated.

Crystalline silicon films sputtered on molybdenum A study of the silicon-molybdenum interface

Energy Technology Data Exchange (ETDEWEB)

Reinig, P.; Fenske, F.; Fuhs, W.; Schoepke, A.; Selle, B

2003-04-15

Polycrystalline silicon films were grown on molybdenum (Mo)-coated substrates at high deposition rate using the pulsed magnetron sputtering technique. Our study investigates the silicon-molybdenum interface of these films to elucidate stimulating mechanisms for an ordered crystalline silicon thin film growth. Both Auger electron spectroscopy and Rutherford backscattering reveal that at a substrate temperature as low as T{sub S}=450 deg. C during the deposition process intermixing of Si and Mo at the Si-Mo interface takes place leading to a compositional ratio Mo:Si of about 1:2. By Raman spectroscopy hexagonal {beta}-MoSi{sub 2} could be identified as the dominant phase in this intermixed region. The dependence of the resulting thickness of the reacted interface layer on the deposition conditions is not fully understood yet.

Crystalline silicon films sputtered on molybdenum A study of the silicon-molybdenum interface

International Nuclear Information System (INIS)

Reinig, P.; Fenske, F.; Fuhs, W.; Schoepke, A.; Selle, B.

2003-01-01

Polycrystalline silicon films were grown on molybdenum (Mo)-coated substrates at high deposition rate using the pulsed magnetron sputtering technique. Our study investigates the silicon-molybdenum interface of these films to elucidate stimulating mechanisms for an ordered crystalline silicon thin film growth. Both Auger electron spectroscopy and Rutherford backscattering reveal that at a substrate temperature as low as T S =450 deg. C during the deposition process intermixing of Si and Mo at the Si-Mo interface takes place leading to a compositional ratio Mo:Si of about 1:2. By Raman spectroscopy hexagonal β-MoSi 2 could be identified as the dominant phase in this intermixed region. The dependence of the resulting thickness of the reacted interface layer on the deposition conditions is not fully understood yet

Low resistivity molybdenum thin film towards the back contact of dye ...

Indian Academy of Sciences (India)

Abstract. This paper reports the optimization of the molybdenum thin film electrode as the back contact of dye-sensitized solar cell (DSSC). The molybdenum thin film was grown on the glass substrate by direct current sputtering techniques of which the sputtering power was 150Wat 18 sccm flow rate of Ar. At such sputtering ...

Structural and optical properties of electrodeposited molybdenum oxide thin films

International Nuclear Information System (INIS)

Patil, R.S.; Uplane, M.D.; Patil, P.S.

2006-01-01

Electrosynthesis of Mo(IV) oxide thin films on F-doped SnO 2 conducting glass (10-20/Ω/□) substrates were carried from aqueous alkaline solution of ammonium molybdate at room temperature. The physical characterization of as-deposited films carried by thermogravimetric/differential thermogravimetric analysis (TGA/DTA), infrared spectroscopy and X-ray diffraction (XRD) showed the formation of hydrous and amorphous MoO 2 . Scanning electron microscopy (SEM) revealed a smooth but cracked surface with multi-layered growth. Annealing of these films in dry argon at 450 deg. C for 1 h resulted into polycrystalline MoO 2 with crystallites aligned perpendicular to the substrate. Optical absorption study indicated a direct band gap of 2.83 eV. The band gap variation consistent with Moss rule and band gap narrowing upon crystallization was observed. Structure tailoring of as-deposited thin films by thermal oxidation in ambient air to obtain electrochromic Mo(VI) oxide thin films was exploited for the first time by this novel route. The results of this study will be reported elsewhere

Comparison of various methods of measuring thin oxide layers formed on molybdenum and titanium

International Nuclear Information System (INIS)

Lepage, F.; Bardolle, J.; Boulben, J.M.

1975-01-01

The problem of the growth of thin layers is very interesting from both the fundamental and technological viewpoints. This work deals with oxide films produced on two metals, molybdenum and titanium. The thicknesses obtained by various methods (microgravimetry, nuclear reactions and spectrophotometry) are compared and the advantages and disadvantages of each method are shown [fr

Study of the oxidation kinetics of the nickel-molybdenum alloy

International Nuclear Information System (INIS)

Gouillon, Marie-Josephe

1974-01-01

This research thesis reports the study of the oxidation of a nickel-molybdenum alloy in the high-nickel-content part of this alloy. After a bibliographical study on the both metals, the author proposes a physical model based on observed phenomena and based on experimental results. Based on a thermodynamic study, the author compares the stability of the different oxides which may be formed, and reports a prediction of oxides obtained on the alloy during oxidation. Qualitative and quantitative studies have been performed by scanning electron microscopy coupled with electronic microprobe analysis to investigate morphological characteristics on oxidation films. A kinetic study by thermogravimetry shows a decrease of the alloy oxidation rate with respect to that of pure nickel at temperatures lower than 800 degrees C. This result is interpreted by the intervention of two opposed diffusion phenomena which act against each other [fr

Catalytic activity of oxide cerium-molybdenum-tellurium catalysts in oxidation ammonolysis

International Nuclear Information System (INIS)

Dzhordano, N.; Bart, D.; Madzhori, R.

1984-01-01

A commercial catalyst containing a mixture of Ce-, Mo-, Te oxides deposited on SiO 2 is shown to manifest a high efficiency in oxidative ammonolysis of propylene (C 3 - ) to acrylonitrile (AN). The dependence of the catalytic properties on the catalyst composition and reaction conditions is studied. It is established that three-component mixtures are more active and selective than the systems with a lesser number of components. Using the catalyst with the optimum ratio of constituent oxides in a microreactor at 440 deg enabled one to achieve initial selectivity in terms of AN equal to 82.5% at 97% conversion of C 3 - . Acrolein, acetonitrile, HCN and nitrogen oxides are the reaction by-products. A supposition is made that the reaction proceeds via the formation of π-compleXes on the centres of Te(4). Setective oxidation occurs on oxygen atoms bonded with the Mo(6) ions. Tellurium enhances the molybdenum reducibleness due to delocalization of electrons, whereas the cerium addition to the mixture of tellurium- and molybdenum oxides increases the rate of molybdenum reoxidation and thus enhances the catalytic system stability

Cathodic electrodeposition of mixed molybdenum tungsten oxides from peroxo-polymolybdotungstate solutions.

Science.gov (United States)

Kondrachova, Lilia; Hahn, Benjamin P; Vijayaraghavan, Ganesh; Williams, Ryan D; Stevenson, Keith J

2006-12-05

Mixed molybdenum tungsten trioxide films of varying stoichiometry (MoxW1 - xO3, 0 cathodic electrodeposition on indium tin oxide (ITO)-coated glass substrates from aqueous peroxo-polymolybdotungstate solutions. Electrochemical quartz crystal microbalance (EQCM), cyclic voltammetry, and chronocoulometry were used to gain insight into the electrodeposition mechanism. The compositional and structural properties were characterized for MoxW1 - xO3 films deposited at intermediate potentials (-0.35 V vs Ag/AgCl) and sintered at 250 degrees C using energy-dispersive spectroscopy, X-ray diffraction, and Raman spectroscopy. These studies reveal that films consist of homogeneously mixed MoxW1 - xO3, with an enriched Mo content ranging in composition from 0.4 < x < 0.7 depending upon the mol % Mo present in the deposition solution. Chronoamperometry and spectroelectrochemical measurements were conducted to estimate lithium ion diffusion coefficients and coloration efficiencies for the mixed metal oxide films in 1 M LiClO4/propylene carbonate. The subtle interplay between structural and compositional properties due to the uniform mixing of Mo and W oxide components shows that electrochromic and lithium ion transport properties are moderately enhanced relative to those of single-component WO3 and MoO3 and demonstrate improved structural stability over pure MoO3 polymorphs during electrochemical cycling.

Room-temperature solution synthesis of Ag nanoparticle functionalized molybdenum oxide nanowires and their catalytic applications

International Nuclear Information System (INIS)

Dong Wenjun; Huang Huandi; Zhu Yanjun; Li Xiaoyun; Wang Xuebin; Li Chaorong; Chen Benyong; Wang Ge; Shi Zhan

2012-01-01

A simple chemical solution route for the synthesis of large-scale high-quality Ag nanoparticle functionalized molybdenum oxide nanowire at room temperature has been developed. In the synthesis, the protonated amine was intercalated into the molybdenum bronze layers to reduce the electrostatic force of the lamellar structures, and then the Ag nanoparticle functionalized long nanowires could be easily induced by a redox reaction between a molybdenum oxide–amine intermediate and Ag + at room temperature. The intercalation lamellar structures improved the nucleation and growth of the Ag nanoparticles, with the result that uniform Ag nanoparticles occurred on the surface of the MoO 3 nanowire. In this way Ag nanoparticles with average sizes of around 6 nm, and high-purity nanowires with mean diameter of around 50 nm and with typical lengths of several tens to hundreds of micrometers were produced. The heteronanostructured nanowires were intricately and inseparably connected to each other with hydrogen bonds and/or bridge oxygen atoms and packed together, forming a paper-like porous network film. The Ag–MoO 3 nanowire film performs a promoted catalytic property for the epoxidation of cis-cyclooctene, and the heteronanostructured nanowire film sensor shows excellent sensing performance to hydrogen and oxygen at room temperature. (paper)

Synthesis of low oxygen concentration molybdenum nitride films

International Nuclear Information System (INIS)

Roberson, S.L.; Davis, R.F.; Finello, D.

1998-01-01

Polycrystalline, small grain size, 15 μm thick Mo x N (x = 1 and 2) films containing ∼60 at.% γ-Mo 2 N and ∼40 at.% δ-MoN and void of Auger detectable concentrations of molybdenum oxides, have been prepared on 50-μm thick nitrided Ti substrates via programmed reaction and subsequent anneal at 750 C for 2 h of the precursor MoO 3 films with NH 3 . The latter films were prepared via liquid spray pyrolysis of an MoCl 5 /methanol mixture in air at 500 C. By contrast, residual MoO 2 occurred near the film-substrate interface in Mo x N films produced using the same programmed reaction but where MoO 3 had been deposited on bare Ti substrates. The change in density of MoO 3 (ρ = 4.69 gcm -3 ) to γ-Mo 2 N (ρ = 9.50 gcm -3 ) and δ-MoN (ρ = 9.05 gcm -3 ), as well as the nature of the topotactic conversion, produced grains which had a calculated average size of 10 nm and which exhibited good adhesion to the substrate. Variations in the conversion heating rates and the NH 3 flow rates also affected both the phase composition and the average grain size of the intermediate and the final reaction products. Scanning electron microscopy (SEM) of the Mo x N films revealed a highly porous surface morphology. (orig.)

A study on direct alloying with molybdenum oxides by feed wire method

Directory of Open Access Journals (Sweden)

Jingjing Zou

2018-04-01

Full Text Available Direct alloying with molybdenum oxides has been regarded in years; the main addition methods are adding to the bottom of electric arc furnace (EAF with scrap, adding to the ladle during the converter tapping and mixing molybdenum oxide, lime and reductant to prepare pellet added to basic oxygen furnace (BOF. In this paper, a new method for direct alloying with molybdenum trioxide is proposed, adding molybdenum trioxide molten steel by feeding wire method in ladle furnace (LF refining process. The feasibility of molybdenum oxide reduction, the influence rules of bottom-blown on liquid steel fluidity and the yield of molybdenum by feeding wire method were analyzed. Results show that molybdenum oxide can be reduced by [Al], [Si], [C], and even [Fe] in molten steel. Bottom blowing position has a significant influence on the flow of molten steel when the permeable brick is located in 1/2 radius. The yields of Mo are higher than 97% for the experiments with feed wire method, the implementation of direct alloying with molybdenum trioxide by feed wire method works even better than that uses of ferromolybdenum in the traditional process.

Microstructure and mechanical properties of multi-components rare earth oxide-doped molybdenum alloys

International Nuclear Information System (INIS)

Zhang Guojun; Sun Yuanjun; Zuo Chao; Wei Jianfeng; Sun Jun

2008-01-01

Pure molybdenum and molybdenum alloys doped with two- or three-components rare earth oxide particles were prepared by powder metallurgy. Both the tensile property and fracture toughness of the pure molybdenum and multi-components rare earth oxide-doped molybdenum alloys were determined at room temperature. The multi-components rare earth oxide-doped molybdenum alloys are fine grained and contain a homogeneous distribution of fine particles in the submicron and nanometer size ranges, which is why the molybdenum alloys have higher strength and fracture toughness than pure molybdenum. Quantitative analysis is used to explain the increase in yield strength with respect to grain size and second phase strengthening. Furthermore, the relationship between the tensile properties and microstructural parameters is quantitatively established

Bioaccessibility of micron-sized powder particles of molybdenum metal, iron metal, molybdenum oxides and ferromolybdenum--Importance of surface oxides.

Science.gov (United States)

Mörsdorf, Alexander; Odnevall Wallinder, Inger; Hedberg, Yolanda

2015-08-01

The European chemical framework REACH requires that hazards and risks posed by chemicals, including alloys and metals, that are manufactured, imported or used in different products (substances or articles) are identified and proven safe for humans and the environment. Metals and alloys need hence to be investigated on their extent of released metals (bioaccessibility) in biologically relevant environments. Read-across from available studies may be used for similar materials. This study investigates the release of molybdenum and iron from powder particles of molybdenum metal (Mo), a ferromolybdenum alloy (FeMo), an iron metal powder (Fe), MoO2, and MoO3 in different synthetic body fluids of pH ranging from 1.5 to 7.4 and of different composition. Spectroscopic tools and cyclic voltammetry have been employed to characterize surface oxides, microscopy, light scattering and nitrogen absorption for particle characterization, and atomic absorption spectroscopy to quantify released amounts of metals. The release of molybdenum from the Mo powder generally increased with pH and was influenced by the fluid composition. The mixed iron and molybdenum surface oxide of the FeMo powder acted as a barrier both at acidic and weakly alkaline conditions. These findings underline the importance of the surface oxide characteristics for the bioaccessibility of metal alloys. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Effect of drying method on properties of vanadium-molybdenum oxide catalysts

International Nuclear Information System (INIS)

Gorshkova, T.P.; Savchenko, L.A.; Tarasova, D.V.; Tret'yakov, Yu.D.; Olen'kova, I.P.; Nikoro, T.A.; Maksimov, N.G.

1981-01-01

Effect of drying method of molybdenum and vanadium salt solutions on physicochemical and catalytical properties of vanadium-molybdenum catalysts is studied. It is shown that the drying method of solutions determines the completeness of vanadium binding into oxide vanadium-molybdenum compounds and thus effects the activity and selectivity of catalysts in acrolein oxidation into acrylic acid. Besides the drying method determines the porous structure of catalysts [ru

Synthesis and Characterization of Molybdenum Doped ZnO Thin Films by SILAR Deposition Method

Science.gov (United States)

Radha, R.; Sakthivelu, A.; Pradhabhan, D.

2016-08-01

Molybdenum (Mo) doped zinc oxide (ZnO) thin films were deposited on the glass substrate by Successive Ionic Layer Adsorption and Reaction (SILAR) deposition method. The effect of Mo dopant concentration of 5, 6.6 and 10 mol% on the structural, morphological, optical and electrical properties of n-type Mo doped ZnO films was studied. The X-ray diffraction (XRD) results confirmed that the Mo doped ZnO thin films were polycrystalline with wurtzite structure. The field emission scanning electron microscopy (FESEM) studies shows that the surface morphology of the films changes with Mo doping. A blue shift of the optical band gap was observed in the optical studies. Effect of Mo dopant concentration on electrical conductivity was studied and it shows comparatively high electrical conductivity at 10 mol% of Mo doping concentration.

A study on molybdenum sulphoselenide (MoSxSe2−x, 0 ≤ x ≤ 2) thin films: Growth from solution and its properties

International Nuclear Information System (INIS)

Anand, T. Joseph Sahaya; Shariza, S.

2012-01-01

Highlights: ► Effect of deposition time on the properties of molybdenum chalcogenide thin films. ► First time to compare the study of binary and ternary molybdenum chalcogenides. ► No previous report on ternary molybdenum sulphoselenide by electrodeposition. ► Semiconducting parameters by CV analysis promising to be good solar cell material. - Abstract: Thin films of molybdenum sulphoselenide, MoS x Se 2−x , (0 ≤ x ≤ 2) have been electrosynthesized on indium-tin-oxide (ITO)-coated glass and stainless steel substrates. The films were characterized for their structural, morphological and compositional characteristics. Their optical and semiconducting parameters were also analysed in order to determine the suitability of the thin films for photoelectrochemical (PEC)/solar cell applications. Structural analysis via X-ray diffraction (XRD) analysis reveals that the films are polycrystalline in nature. Scanning electron microscope (SEM) studies reveals the films were adherent to the substrate with uniform in nature which also confirmed by Transmission electron microscope (TEM). Compositional analysis via energy dispersive X-ray (EDX) technique confirms the presence of Mo, S and Se elements in the films. The optical studies show that the films are of direct bandgap. Results on the semiconductor parameters analysis of the films showed that the nature of the Mott–Schottky plots indicates that the films obtained are of n-type material. For all films, the semiconductor parameter values come in the better range of other transition metal chalcogenides which has proven that MoSSe thin films are capable as solar/PEC cell materials.

On the effect of interaction of molybdenum trioxide and magnesium oxide in water

International Nuclear Information System (INIS)

Bunin, V.M.; Karelin, A.I.; Solov'eva, L.N.

1992-01-01

Interaction of molybdenum trioxide and magnesium oxide in water was studied. It is shown that molybdenum trioxide forms consecutively magnesium molybdate, dimolybdate and magnesium polymolybdates with magnesium oxide

Synergistic Effect of Nitrogen and Molybdenum on Localized Corrosion of Stainless Steels

International Nuclear Information System (INIS)

Kim, Y. S.

2010-01-01

According to the bipolar model, ion selectivity of some species in the passive film is important factor to control the passivation. An increase of cation selectivity of outer layer of the passive film can stabilize the film and improves the corrosion resistance. Therefore, the formation and roles of ionic species in the passive film should be elucidated. In this work, two types of solution (hydrochloric or sulfuric acid) were used to test high N and Mo-bearing stainless steels. The objective of this work was to investigate the formation of oxyanions in the passive film and the roles of oxyanions in passivation of stainless steel. Nitrogen exists as atomic nitrogen, nitric oxide, nitro-oxyanions (NO x - ), and N-H species, not nitride in the passive film. Because of its high mobility, the enriched atomic nitrogen can act as a reservoir. The formation of N-H species buffers the film pH and facilitates the formation of oxyanions in the film. NO x - species improve the cation selectivity of the film, increasing the oxide content and film density. NO x - acts similar to a strong inhibitor both in the passive film and at active sites. This facilitates the formation of chromium oxide. Also, NO x - can make more molybdate and nitric oxide by reacting with Mo. The role of Mo addition on the passivation characteristics of stainless steel may differ with the test environment. Mo exists as metallic molybdenum, Molybdenum oxide, and molybdate and the latter facilitates the oxide formation. When nitrogen and molybdenum coexist in stainless steel, corrosion resistance in chloride solutions is drastically increased. This synergistic effect of N and Mo in a chloride solution is mainly due to the formation of nitro-oxyanions and molybdate ion. Oxyanions can be formed by a 'solid state reaction' in the passive film, resulting in the formation of more molybdate and nitric oxide. These oxyanions improve the cation selectivity of the outer layer and from more oxide and increase the

Molybdenum Doped SnO2 Thin Films as a Methanol Vapor Sensor

Directory of Open Access Journals (Sweden)

Patil Shriram B.

2013-02-01

Full Text Available The molybdenum doped SnO2 thin films were synthesized by conventional spray pyrolysis route and has been investigated for the methanol vapor sensing. The structural and elemental composition analysis of thin films was carried out by X- ray diffraction and Scanning Electron Microscopy (SEM and Energy Dispersive X-ray spectroscopy (EDAX.The XRD spectrum revealed that the thin films have the polycrystalline nature with a mixed phase comprising of SnO2 and MoO3. The scanning Electron Microscopy (SEM clears that the surface morphology observed to be granular, uniformly covering the entire surface area of the thin film. The methanol vapor sensing studies were performed in dry air at the different temperatures. The influence of the concentration of Molybdenum and operating temperature on the sensor performance has been investigated.

Thermal transport properties of polycrystalline tin-doped indium oxide films

International Nuclear Information System (INIS)

Ashida, Toru; Miyamura, Amica; Oka, Nobuto; Sato, Yasushi; Shigesato, Yuzo; Yagi, Takashi; Taketoshi, Naoyuki; Baba, Tetsuya

2009-01-01

Thermal diffusivity of polycrystalline tin-doped indium oxide (ITO) films with a thickness of 200 nm has been characterized quantitatively by subnanosecond laser pulse irradiation and thermoreflectance measurement. ITO films sandwiched by molybdenum (Mo) films were prepared on a fused silica substrate by dc magnetron sputtering using an oxide ceramic ITO target (90 wt %In 2 O 3 and 10 wt %SnO 2 ). The resistivity and carrier density of the ITO films ranged from 2.9x10 -4 to 3.2x10 -3 Ω cm and from 1.9x10 20 to 1.2x10 21 cm -3 , respectively. The thermal diffusivity of the ITO films was (1.5-2.2)x10 -6 m 2 /s, depending on the electrical conductivity. The thermal conductivity carried by free electrons was estimated using the Wiedemann-Franz law. The phonon contribution to the heat transfer in ITO films with various resistivities was found to be almost constant (λ ph =3.95 W/m K), which was about twice that for amorphous indium zinc oxide films

A redox-assisted molecular assembly of molybdenum oxide amine composite nanobelts

International Nuclear Information System (INIS)

Luo Haiyan; Wei Mingdeng; Wei Kemei

2011-01-01

Research highlights: → Nanobelts of molybdenum oxide amine were first synthesized via a redox-assisted molecular assembly route. → These nanobelts are highly crystalline with a several tens of micrometers in length and 20-30 nm in thickness. - Abstract: In this paper, the nanobelts of molybdenum oxide amine composite were successfully synthesized via a redox-assisted molecular assembly route under the hydrothermal conditions. The synthesized nanobelts were characterized by XRD, SEM, TEM, TG and FT-IR measurements. The thickness of nanobelts is found to be ca. 20-30 nm and their lengths are up to several tens of micrometers. Based on a series of the experimental results, a possible model, redox-intercalation-exfoliation, was suggested for the formation of nanobelts of molybdenum oxide amine composite.

Enhanced superconductivity and superconductor to insulator transition in nano-crystalline molybdenum thin films

Energy Technology Data Exchange (ETDEWEB)

Sharma, Shilpam; Amaladass, E.P. [Condensed Matter Physics Division, Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India); Sharma, Neha [Surface & Nanoscience Division, Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India); Harimohan, V. [Condensed Matter Physics Division, Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India); Amirthapandian, S. [Materials Physics Division, Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India); Mani, Awadhesh, E-mail: mani@igcar.gov.in [Condensed Matter Physics Division, Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India)

2017-06-01

Disorder driven superconductor to insulator transition via intermediate metallic regime is reported in nano-crystalline thin films of molybdenum. The nano-structured thin films have been deposited at room temperature using DC magnetron sputtering at different argon pressures. The grain size has been tuned using deposition pressure as the sole control parameter. A variation of particle sizes, room temperature resistivity and superconducting transition has been studied as a function of deposition pressure. The nano-crystalline molybdenum thin films are found to have large carrier concentration but very low mobility and electronic mean free path. Hall and conductivity measurements have been used to understand the effect of disorder on the carrier density and mobilities. Ioffe-Regel parameter is shown to correlate with the continuous metal-insulator transition in our samples. - Highlights: • Thin films of molybdenum using DC sputtering have been deposited on glass. • Argon background pressure during sputtering was used to tune the crystallite sizes of films. • Correlation in deposition pressure, disorder and particle sizes has been observed. • Disorder tuned superconductor to insulator transition along with an intermediate metallic phase has been observed. • Enhancement of superconducting transition temperature and a dome shaped T{sub C} vs. deposition pressure phase diagram has been observed.

Structure, activity and kinetics of supported molybdenum oxide and mixed molybdenum-vanadium oxide catalysts prepared by flame spray pyrolysis for propane OHD

DEFF Research Database (Denmark)

Høj, Martin; Kessler, Thomas; Beato, Pablo

2013-01-01

reflectance UV-vis spectroscopy and evaluated as catalysts for the oxidative dehydrogenation (ODH) of propane. The results show that samples with high specific surface areas between 122 and 182 m2/g were obtained, resulting in apparent MoOx and VOx surface densities from 0.7 to 7.7 nm -2 and 1.5 to 1.9 nm-2......, respectively. Raman spectroscopy, UV-vis spectroscopy and XRD confirmed the high dispersion of molybdenum and vanadia species on γ-Al2O3 as the main crystalline phase. Only at the highest loading of 15 wt% Mo, with theoretically more than monolayer coverage, some crystalline molybdenum oxide was observed...

Investigation of the oxidative ammonolysis of propylene on oxide catalysts containing molybdenum and using the response method

International Nuclear Information System (INIS)

Gadzhiev, K.N.; Adzhamov, K.Y.; Alkhazov, T.G.; Khanmamedova, A.K.

1985-01-01

The response method has been used to study the oxidative ammonolysis of propylene on MoO 3 and molybdenum oxide systems containing bismuth, silicon, and phosphorous ions. The response curves obtained for ammonia, propylene, CO 2 , acrolein, acrylonitrile in these systems are discussed and compared with individual molybdenum trioxide. It has been shown that the modifying action of ammonia on the catalyst surfaces determines the direction of the oxidative conversion of the propylene

Electrophysical properties of molybdenum films in conditions of internal dimension effect

International Nuclear Information System (INIS)

Byilous, O.A.; Chornous, A.M.

2003-01-01

This article is devoted to complex research of crystal structure and electrophysical properties (resistivity and temperature coefficient of resistance) molybdenum films. Calculation of electro carry parameters (mean free path of electrons in film, the transmission and reflectivity coefficient at the grain boundary) isotropic model of Tellier-Tosser-Pichard and asymptotic expression Ukhlinov-Kosacivska model and Mayadas-Shatzkes theories

Effect of acetic acid on wet patterning of copper/molybdenum thin films in phosphoric acid solution

International Nuclear Information System (INIS)

Seo, Bo.-Hyun; Lee, Sang-Hyuk; Park, In-Sun; Seo, Jong Hyun; Choe, HeeHwan; Jeon, Jae-Hong; Hong, Munpyo; Lee, Yong Uk; Winkler, Joerg

2011-01-01

Copper metallization is a key issue for high performance thin film transistor (TFT) technology. A phosphoric acid based copper etchant is a potentially attractive alternative to the conventional hydrogen peroxide based etchant due to its longer-life expectancy time and higher stability in use. In this paper, it is shown that amount of the acetic acid in the phosphoric based copper etchant plays an important role in controlling the galvanic reaction between the copper and the molybdenum. As the concentration of acetic acid in the phosphoric mixture solution increased from 0 M to 0.4 M, the measured galvanic current density dropped from 32 mA/cm 2 to 26 mA/cm 2 , indicating that the acetic acid induces the lower galvanic reaction between the copper and the molybdenum in the solution. From the XPS analysis, with the addition of the acetic acid, the thickness of the protective MoO 2 passive film covering the molybdenum surface grew and the dissolution rate of the molybdenum thin film decreased. However, the dissolution rate of the copper thin film increased as the concentration of acetic acid in the mixture solution increased.

Effect of acetic acid on wet patterning of copper/molybdenum thin films in phosphoric acid solution

Energy Technology Data Exchange (ETDEWEB)

Seo, Bo.-Hyun; Lee, Sang-Hyuk; Park, In-Sun [Department of Materials Engineering, Korea Aerospace University, Hwajeon, Goyang, Gyonggi-do 412-791 (Korea, Republic of); Seo, Jong Hyun, E-mail: jhseo@kau.ac.kr [Department of Materials Engineering, Korea Aerospace University, Hwajeon, Goyang, Gyonggi-do 412-791 (Korea, Republic of); Choe, HeeHwan; Jeon, Jae-Hong [School of Electronics, Telecommunications and Computer Engineering, Korea Aerospace University, Hwajeon, Goyang, Gyonggi-do 412-791 (Korea, Republic of); Hong, Munpyo [Display and Semiconductor Physics, Korea University (Korea, Republic of); Lee, Yong Uk [PETEC (The Printable Electronics Technology Centre) (United Kingdom); Winkler, Joerg [PLANSEE Metal GmbH, Metallwerk-Plansee-Str. 71A-6600, Reutte (Austria)

2011-08-01

Copper metallization is a key issue for high performance thin film transistor (TFT) technology. A phosphoric acid based copper etchant is a potentially attractive alternative to the conventional hydrogen peroxide based etchant due to its longer-life expectancy time and higher stability in use. In this paper, it is shown that amount of the acetic acid in the phosphoric based copper etchant plays an important role in controlling the galvanic reaction between the copper and the molybdenum. As the concentration of acetic acid in the phosphoric mixture solution increased from 0 M to 0.4 M, the measured galvanic current density dropped from 32 mA/cm{sup 2} to 26 mA/cm{sup 2}, indicating that the acetic acid induces the lower galvanic reaction between the copper and the molybdenum in the solution. From the XPS analysis, with the addition of the acetic acid, the thickness of the protective MoO{sub 2} passive film covering the molybdenum surface grew and the dissolution rate of the molybdenum thin film decreased. However, the dissolution rate of the copper thin film increased as the concentration of acetic acid in the mixture solution increased.

Effect of oxidizing environment on mechanical properties of molybdenum and TZM

International Nuclear Information System (INIS)

Liu, C.T.; Anderson, S.H.; Inouye, H.

1978-10-01

The effect of environment on mechanical properties of molybdenum and TZM was investigated in low-pressure (1.3-mPa) oxygen at 1150 0 C. Specimens of TZM picked up oxygen and lost carbon. The oxygen concentration increases linearly with exposure time, indicating that the chemisorption of oxygen molecules at the specimen surface, rather than bulk diffusion, controls the kinetics of oxygen absorption at 1150 0 C. Specimens of TZM increase in tensile strength and decrease in ductility with increasing oxygen content. Exposed TZM loses its ductility at elevated temperatures at an oxygen level of 500 ppM. The embrittlement is due to the formation of zones or oxide precipitates, which harden the alloy and promote the brittle fracture associated with cleavage and grain-boundary separation. Unalloyed molybdenum responds to the oxidizing environment quite differently from TZM. The molybdenum (containing no active element such as Ti and Zr) showed no internal oxidation at 1150 0 C. Instead, our results indicate that a trace of oxygen penetrated into molybdenum through its grain boundaries. This penetration raises the ductile-to-brittle transition temperature of molybdenum by 200 0 C lowers the ductility above 900 0 C. The ductility of oxygen-exposed molybdenum is virtually unaffected in the temperature range from 400 to 900 0 C. A ductility minimum (10%) is observed at 1350 0 C because of dynamic embrittlement effects; that is, diffusion of oxygen to grain boundaries or crack tips where high triaxial states of stress are generated during plastic deformation. This embrittlement can be totally eliminated by an increase in strain rate

Vanadium and molybdenum oxide thin films on Au(111). Growth and surface characterization

Energy Technology Data Exchange (ETDEWEB)

Guimond, Sebastien

2009-06-04

The growth and the surface structure of well-ordered V{sub 2}O{sub 3}, V{sub 2}O{sub 5} and MoO{sub 3} thin films have been investigated in this work. These films are seen as model systems for the study of elementary reaction steps occurring on vanadia and molybdena-based selective oxidation catalysts. It is shown that well-ordered V{sub 2}O{sub 3}(0001) thin films can be prepared on Au(111). The films are terminated by vanadyl groups which are not part of the V{sub 2}O{sub 3} bulk structure. Electron irradiation specifically removes the oxygen atoms of the vanadyl groups, resulting in a V-terminated surface. The fraction of removed vanadyl groups is controlled by the electron dose. Such surfaces constitute interesting models to probe the relative role of both the vanadyl groups and the undercoordinated V ions at the surface of vanadia catalysts. The growth of well-ordered V{sub 2}O{sub 5}(001) and MoO{sub 3}(010) thin films containing few point defects is reported here for the first time. These films were grown on Au(111) by oxidation under 50 mbar O{sub 2} in a dedicated high pressure cell. Contrary to some of the results found in the literature, the films are not easily reduced by annealing in UHV. This evidences the contribution of radiation and surface contamination in some of the reported thermal reduction experiments. The growth of ultrathin V{sub 2}O{sub 5} and MoO{sub 3} layers on Au(111) results in formation of interface-specific monolayer structures. These layers are coincidence lattices and they do not correspond to any known oxide bulk structure. They are assumed to be stabilized by electronic interaction with Au(111). Their formation illustrates the polymorphic character and the ease of coordination units rearrangement which are characteristic of both oxides. The formation of a second layer apparently precedes the growth of bulk-like crystallites for both oxides. This observation is at odds with a common assumption that crystals nucleate as soon as a

Vanadium and molybdenum oxide thin films on Au(111). Growth and surface characterization

International Nuclear Information System (INIS)

Guimond, Sebastien

2009-01-01

The growth and the surface structure of well-ordered V 2 O 3 , V 2 O 5 and MoO 3 thin films have been investigated in this work. These films are seen as model systems for the study of elementary reaction steps occurring on vanadia and molybdena-based selective oxidation catalysts. It is shown that well-ordered V 2 O 3 (0001) thin films can be prepared on Au(111). The films are terminated by vanadyl groups which are not part of the V 2 O 3 bulk structure. Electron irradiation specifically removes the oxygen atoms of the vanadyl groups, resulting in a V-terminated surface. The fraction of removed vanadyl groups is controlled by the electron dose. Such surfaces constitute interesting models to probe the relative role of both the vanadyl groups and the undercoordinated V ions at the surface of vanadia catalysts. The growth of well-ordered V 2 O 5 (001) and MoO 3 (010) thin films containing few point defects is reported here for the first time. These films were grown on Au(111) by oxidation under 50 mbar O 2 in a dedicated high pressure cell. Contrary to some of the results found in the literature, the films are not easily reduced by annealing in UHV. This evidences the contribution of radiation and surface contamination in some of the reported thermal reduction experiments. The growth of ultrathin V 2 O 5 and MoO 3 layers on Au(111) results in formation of interface-specific monolayer structures. These layers are coincidence lattices and they do not correspond to any known oxide bulk structure. They are assumed to be stabilized by electronic interaction with Au(111). Their formation illustrates the polymorphic character and the ease of coordination units rearrangement which are characteristic of both oxides. The formation of a second layer apparently precedes the growth of bulk-like crystallites for both oxides. This observation is at odds with a common assumption that crystals nucleate as soon as a monolayer is formed dur-ing the preparation of supported vanadia

The optimization of molybdenum back contact films for Cu(In,Ga)Se{sub 2} solar cells by the cathodic arc ion plating method

Energy Technology Data Exchange (ETDEWEB)

Cho, Yong Ki, E-mail: choyk@kitech.re.kr [Heat Treatment and Surface Engineering R and D Group, Korea Institute of Industrial Technology, Incheon 406-840 (Korea, Republic of); Department of Physics, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Kim, Gang Sam; Song, Young Sik; Lim, Tae Hong [Heat Treatment and Surface Engineering R and D Group, Korea Institute of Industrial Technology, Incheon 406-840 (Korea, Republic of); Jung, Donggeun [Department of Physics, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)

2013-12-02

Molybdenum back contact films for Cu(In,Ga)Se{sub 2} (CIGS) solar cells have been deposited using DC magnetron sputtering methods. The electronic pathway properties of the molybdenum film have been highly dependent on the working gas pressure in magnetron sputtering, which should be carefully controlled to obtain high conductivity and adhesion. A coating method, cathodic arc ion plating, was used for molybdenum back contact electrode fabrication. The aim of this work was to find a metallization method for CIGS solar cells, which has less sensitivity on the working pressure. The resistivity, grain size, growth structures, stress, and efficiency of the films in CIGS solar cells were investigated. The results reveal that the growth structures of the molybdenum films mainly affect the conductivity. The lowest electrical resistivity of the ion-plated molybdenum films was 6.9 μΩ-cm at a pressure of 0.7 Pa. The electrical resistivity variation showed a gently increasing slope with linearity under a working gas pressure of 13.3 Pa. However, a high value of the residual stress of over 1.3 GPa was measured. In order to reduce stress, titanium film was selected as the buffer layer material, and the back contact films were optimized by double-layer coating of two kinds of hetero-materials with arc ion plating. CIGS solar cells prepared molybdenum films to measure the efficiency and to examine the effects of the back contact electrode. The resistivity, grain size, and surface morphology of molybdenum films were measured by four-point probe, X-ray diffraction, and a scanning electron microscope. The residual stress of the films was calculated from differences in bending curvatures measured using a laser beam. - Highlights: • Molybdenum back contact films for Cu(In,Ga)Se{sub 2} solar cells were prepared by the cathodic arc ion plating. • The lowest electrical resistivity of molybdenum film was 6.9 μΩ-cm. • Titanium buffer layer reduced the compressive residual stress

Low resistivity molybdenum thin film towards the back contact of dye ...

Indian Academy of Sciences (India)

Back contact; molybdenum; DC sputtering; dye-sensitized solar cell. 1. Introduction ... Structure and operation mechanism of a DSSC. Figure 2. Mo layers were .... to a better efficiency. In this work, the Mo thin films obtained by implying different.

Transmission electron microscopy of oxide dispersion strengthened (ODS) molybdenum: effects of irradiation on material microstructure

International Nuclear Information System (INIS)

Baranwal, R.; Burke, M.G.

2003-01-01

Oxide dispersion strengthened (ODS) molybdenum has been characterized using transmission electron microscopy (TEM) to determine the effects of irradiation on material microstructure. This work describes the results-to-date from TEM characterization of unirradiated and irradiated ODS molybdenum. The general microstructure of the unirradiated material consists of fine molybdenum grains (< 5 (micro)m average grain size) with numerous low angle boundaries and isolated dislocation networks. 'Ribbon'-like lanthanum oxides are aligned along the working direction of the product form and are frequently associated with grain boundaries, serving to inhibit grain boundary and dislocation movement. In addition to the 'ribbons', discrete lanthanum oxide particles have also been detected. After irradiation, the material is characterized by the presence of nonuniformly distributed large (∼ 20 to 100 nm in diameter), multi-faceted voids, while the molybdenum grain size and oxide morphology appear to be unaffected by irradiation

Effect of the substrate temperature on the physical properties of molybdenum tri-oxide thin films obtained through the spray pyrolysis technique

International Nuclear Information System (INIS)

Martínez, H.M.; Torres, J.; López Carreño, L.D.; Rodríguez-García, M.E.

2013-01-01

Polycrystalline molybdenum tri-oxide thin films were prepared using the spray pyrolysis technique; a 0.1 M solution of ammonium molybdate tetra-hydrated was used as a precursor. The samples were prepared on Corning glass substrates maintained at temperatures ranging between 423 and 673 K. The samples were characterized through micro Raman, X-ray diffraction, optical transmittance and DC electrical conductivity. The species MoO 3 (H 2 O) 2 was found in the sample prepared at a substrate temperature of 423 K. As the substrate temperature rises, the water disappears and the samples crystallize into α-MoO 3 . The optical gap diminishes as the substrate temperature rises. Two electrical transport mechanisms were found: hopping under 200 K and intrinsic conduction over 200 K. The MoO 3 films' sensitivity was analyzed for CO and H 2 O in the temperature range 160 to 360 K; the results indicate that CO and H 2 O have a reduction character. In all cases, it was found that the sensitivity to CO is lower than that to H 2 O. - Highlights: ► A low cost technique is used which produces good material. ► Thin films are prepared using ammonium molybdate tetra hydrated. ► The control of the physical properties of the samples could be done. ► A calculation method is proposed to determine the material optical properties. ► The MoO 3 thin films prepared by spray pyrolysis could be used as gas sensor.

Thermally evaporated mechanically hard tin oxide thin films for opto-electronic apllications

Energy Technology Data Exchange (ETDEWEB)

Tripathy, Sumanta K.; Rajeswari, V. P. [Centre for Nano Science and Technology, GVP College of Engineering (Autonomous), Visakhapatnam- 530048 (India)

2014-01-28

Tungsten doped tin oxide (WTO) and Molybdenum doped tin oxide (MoTO) thin film were deposited on corn glass by thermal evaporation method. The films were annealed at 350°C for one hour. Structural analysis using Xray diffraction data shows both the films are polycrystalline in nature with monoclinic structure of tin oxide, Sn{sub 3}O{sub 4}, corresponding to JCPDS card number 01-078-6064. SEM photograph showed that both the films have spherical grains with size in the range of 20–30 nm. Compositional analysis was carried out using EDS which reveals the presence of Sn, O and the dopant Mo/W only thereby indicating the absence of any secondary phase in the films. The films are found to contain nearly 6 wt% of Mo, 8 wt% of W as dopants respectively. The transmission pattern for both the films in the spectral range 200 – 2000 nm shows that W doping gives a transparency of nearly 80% from 380 nm onwards while Mo doping has less transparency of 39% at 380nm. Film hardness measurement using Triboscope shows a film hardness of about 9–10 GPa for both the films. It indicates that W or M doping in tin oxide provides the films the added advantage of withstanding the mechanical wear and tear due to environmental fluctuations By optimizing the optical and electrical properties, W/Mo doped tin oxide films may be explored as window layers in opto-electronic applications such as solar cells.

Thermally evaporated mechanically hard tin oxide thin films for opto-electronic apllications

International Nuclear Information System (INIS)

Tripathy, Sumanta K.; Rajeswari, V. P.

2014-01-01

Tungsten doped tin oxide (WTO) and Molybdenum doped tin oxide (MoTO) thin film were deposited on corn glass by thermal evaporation method. The films were annealed at 350°C for one hour. Structural analysis using Xray diffraction data shows both the films are polycrystalline in nature with monoclinic structure of tin oxide, Sn 3 O 4 , corresponding to JCPDS card number 01-078-6064. SEM photograph showed that both the films have spherical grains with size in the range of 20–30 nm. Compositional analysis was carried out using EDS which reveals the presence of Sn, O and the dopant Mo/W only thereby indicating the absence of any secondary phase in the films. The films are found to contain nearly 6 wt% of Mo, 8 wt% of W as dopants respectively. The transmission pattern for both the films in the spectral range 200 – 2000 nm shows that W doping gives a transparency of nearly 80% from 380 nm onwards while Mo doping has less transparency of 39% at 380nm. Film hardness measurement using Triboscope shows a film hardness of about 9–10 GPa for both the films. It indicates that W or M doping in tin oxide provides the films the added advantage of withstanding the mechanical wear and tear due to environmental fluctuations By optimizing the optical and electrical properties, W/Mo doped tin oxide films may be explored as window layers in opto-electronic applications such as solar cells

Effect of substrate properties and thermal annealing on the resistivity of molybdenum thin films

International Nuclear Information System (INIS)

Schmid, U.; Seidel, H.

2005-01-01

In this study, the influence of substrate properties (e.g. roughness characteristics and chemical composition) on the electrical resistivity of evaporated molybdenum thin films is investigated as a function of varying parameters, such as film thickness (25-115 nm) and post-deposition annealing with temperatures up to T PDA = 900 deg. C. A thermally oxidized silicon wafer with very low surface roughness was used as one substrate type. In contrast, a low temperature co-fired ceramics substrate with a glass encapsulant printed in thick film technology is the representative for rough surface morphology. The electrical resistivity follows the prediction of the size effect up to T PDA = 600 deg. C independent of substrate nature. On the silicon-based substrate, the thickness-independent portion of the film resistivity ρ g in the 'as deposited' state is about 29 times higher than the corresponding bulk value for a mono-crystalline sample. Thin films of this refractory metal on the SiO 2 /Si substrate exhibit an average grain size of 4.9 nm and a negative temperature coefficient of resistivity (TCR). On the glass/ceramic-based substrate, however, ρ g is half the value as compared to that obtained on the SiO 2 /Si substrate and the TCR is positive

Electron-Beam Deposition of Superconducting Molybdenum Thin Films for the Development of Mo/Au TES X-Ray Microcalorimeter

Science.gov (United States)

Finkbeiner, Fred Michael; Adams, Joseph S.; Bandler, Simon R.; Betancour-Martinez, Gabriele L.; Brown, Ari David; Chang, Meng-Ping; Chervenak, James A.; Chiao, Meng P.; Datesman, Aaron; Eckart, Megan E.;

Molybdenum Nitride Films: Crystal Structures, Synthesis, Mechanical, Electrical and Some Other Properties

Directory of Open Access Journals (Sweden)

Isabelle Jauberteau

2015-10-01

Full Text Available Among transition metal nitrides, molybdenum nitrides have been much less studied even though their mechanical properties as well as their electrical and catalytic properties make them very attractive for many applications. The δ-MoN phase of hexagonal structure is a potential candidate for an ultra-incompressible and hard material and can be compared with c-BN and diamond. The predicted superconducting temperature of the metastable MoN phase of NaCl-B1-type cubic structure is the highest of all refractory carbides and nitrides. The composition of molybdenum nitride films as well as the structures and properties depend on the parameters of the process used to deposit the films. They are also strongly correlated to the electronic structure and chemical bonding. An unusual mixture of metallic, covalent and ionic bonding is found in the stoichiometric compounds.

Structure and reactivity of molybdenum oxide cluster ions in the gas phase

International Nuclear Information System (INIS)

Goncharov, V.B.; Fialko, E.F.

2002-01-01

A set of cluster ions of molybdenum oxides Mo x O y + (x = 1-5, y = 1-15) was prepared using a combination of the ionic cyclotron resonance method and Knudsen effusion source. Dependence of concentration of different molybdenum oxide ions on the time of retention and their interaction with carbon monoxide was studied. It is shown that Mo x O y + ions with x>3 contain cyclic fragment Mo 3 O 9 in their structure. Oxygen binding energies within ionic clusters Mo x O y + were estimated [ru

Molybdenum Disilicide Oxidation Kinetics in High Temperature Steam

Energy Technology Data Exchange (ETDEWEB)

Wood, Elizabeth Sooby [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Parker, Stephen Scott [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Nelson, Andrew Thomas [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2016-09-07

The Fuel Cycle Research and Development program’s Advanced Fuels Campaign is currently supporting a range of experimental efforts aimed at the development and qualification of ‘accident tolerant’ nuclear fuel forms. One route to enhance the accident tolerance of nuclear fuel is to replace the zirconium alloy cladding, which is prone to rapid oxidation in steam at elevated temperatures, with a more oxidation-resistant cladding. Several cladding replacement solutions have been envisaged. The cladding can be completely replaced with a more oxidation resistant alloy, a layered approach can be used to optimize the strength, creep resistance, and oxidation tolerance of various materials, or the existing zirconium alloy cladding can be coated with a more oxidation-resistant material. Molybdenum is one candidate cladding material favored due to its high temperature creep resistance. However, it performs poorly under autoclave testing and suffers degradation under high temperature steam oxidation exposure. Development of composite cladding architectures consisting of a molybdenum core shielded by a molybdenum disilicide (MoSi₂) coating is hypothesized to improve the performance of a Mo-based cladding system. MoSi₂ was identified based on its high temperature oxidation resistance in O₂ atmospheres (e.g. air and “wet air”). However, its behavior in H₂O is less known. This report presents thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and x-ray diffraction (XRD) results for MoSi₂ exposed to 670-1498 K water vapor. Synthetic air (80-20%, Ar-O₂) exposures were also performed, and those results are presented here for a comparative analysis. It was determined that MoSi₂ displays drastically different oxidation behavior in water vapor than in dry air. In the 670-1498 K temperature range, four distinct behaviors are observed. Parabolic oxidation is exhibited in only 670

XPS and electrochemical studies of the dissolution and passivation of molybdenum-implanted austenitic stainless steels

International Nuclear Information System (INIS)

De Vito, E.; Marcus, P.

1993-01-01

X-ray Photoelectron Spectroscopy (XPS) was used to investigate the chemical composition and the chemical states of the passive film formed on austenitic stainless steels (Fe-19Cr-10Ni (at.%)) which have been implanted with molybdenum (Mo + , 100 keV, 2.5 x 10 16 at./cm 2 ). Prior to passivation the implanted alloy was characterized by RBS (Rutherford Backscattering Spectroscopy) and XPS. Alloys with well-defined surface concentrations of molybdenum were prepared by ion sputtering the implanted alloy in the preparation chamber of the spectrometer, to a fixed point in the implantation profile. The samples were then transferred without air exposure to a glove box with inert gas in which the electrochemical measurements were performed. After passivation, return transfer of the passivated samples was done with the same transfer device to avoid exposure to air. In 0.5 M H 2 SO 4 , the anodic dissolution current density decreases with increasing Mo content on the alloy surface. Surface analysis by XPS showed that the surface is enriched with molybdenum in the Mo 4+ chemical state. The current density in the passive state is similar for both the non-implanted and the implanted alloys. Surface analysis by XPS showed that the passive film has a bilayer structure (inner oxide and outer hydroxide) and that the hydroxide layer present on the surface of the passive film is markedly enriched with molybdenum in the Mo 6+ chemical state. The XPS measurements indicate that the presence of molybdenum favors the formation of chromium hydroxide at the expense of chromium oxide. A significant enrichment of the alloyed (Cr, Ni) and implanted (Mo) elements was also observed in the metallic phase under the passive film. The possible mechanisms of the effect of molybdenum on the corrosion resistance of stainless steels are discussed in light of the obtained surface analytical results

Toward Annealing-Stable Molybdenum-Oxide-Based Hole-Selective Contacts For Silicon Photovoltaics

KAUST Repository

Essig, Stephanie; Dré on, Julie; Rucavado, Esteban; Mews, Mathias; Koida, Takashi; Boccard, Mathieu; Werner, Jé ré mie; Geissbü hler, Jonas; Lö per, Philipp; Morales-Masis, Monica; Korte, Lars; De Wolf, Stefaan; Balllif, Christophe

2018-01-01

Molybdenum oxide (MoOX) combines a high work function with broadband optical transparency. Sandwiched between a hydrogenated intrinsic amorphous silicon passivation layer and a transparent conductive oxide, this material allows a highly efficient

Electrochemical Multi-Coloration of Molybdenum Oxide Bronzes

International Nuclear Information System (INIS)

Lee, Sangmin; Saji, Viswanathan S.; Lee, Chiwoo

2013-01-01

We report a simple electrochemical approach in fabricating multiple colored molybdenum (Mo) oxide bronzes on the surface of a Mo-quartz electrode. A three step electrochemical batch process consisting of linear sweep voltammetry and anodic oxidation followed by cathodic reduction in neutral K 2 SO 4 electrolyte at different end potentials, viz. -0.62, -0.80 and -1.60 V (vs. Hg/HgSO 4 ) yielded red, blue and yellow colored bronzes. The samples produced were analyzed by XRD, EDS, and SIMS. The color variation was suggested to be associated with the cations intercalation into the oxide formed and the simultaneous structural changes that occurred during the cathodic reduction in neutral aqueous medium

Electrochemical Multi-Coloration of Molybdenum Oxide Bronzes

Energy Technology Data Exchange (ETDEWEB)

Lee, Sangmin; Saji, Viswanathan S.; Lee, Chiwoo [Korea Univ., Seoul (Korea, Republic of)

2013-08-15

We report a simple electrochemical approach in fabricating multiple colored molybdenum (Mo) oxide bronzes on the surface of a Mo-quartz electrode. A three step electrochemical batch process consisting of linear sweep voltammetry and anodic oxidation followed by cathodic reduction in neutral K{sub 2}SO{sub 4} electrolyte at different end potentials, viz. -0.62, -0.80 and -1.60 V (vs. Hg/HgSO{sub 4}) yielded red, blue and yellow colored bronzes. The samples produced were analyzed by XRD, EDS, and SIMS. The color variation was suggested to be associated with the cations intercalation into the oxide formed and the simultaneous structural changes that occurred during the cathodic reduction in neutral aqueous medium.

Heterogeneous inhibition of the liquid phase oxidation of hydrocarbons by molybdenum compounds

Energy Technology Data Exchange (ETDEWEB)

Tavadyan, L.A.; Karapetyan, A.P.; Madatovyan, V.M.

1988-05-01

The heterogeneous action of molybdenum compounds: MoB, MoSe/sub 2/, MoSi/sub 2/, Mo/sub 2/C, MoO/sub 3/, Mo on the oxidation of n-decane, ethylbenzene, and nonene-1 has been investigated. A parameter representing the inhibiting effect of the heterogeneous catalyst was calculated theoretically. It was found that NoB, MoSe/sub 2/, and MoSi/sub 2/ inhibited the oxidation of n-decane at 408 K while the remaining heterogeneous contacts catalyzed it. A critical phenomenon was detected in the inhibition by MoSi/sub 2/. All the molybdenum compounds investigated inhibited the oxidation of ethylbenzene at 393 K owing to the formation of phenol by catalytic decomposition of the hydroperoxide. The liquid phase oxidation autoinhibited by phenol is described theoretically.

Effects of oxygen gas flow rate and ion beam plasma conditions on the opto-electronic properties of indium molybdenum oxide films fabricated by ion beam-assisted evaporation

International Nuclear Information System (INIS)

Kuo, C.C.; Liu, C.C.; Lin, C.C.; Liou, Y.Y.; He, J.L.; Chen, F.S.

2008-01-01

The purpose of the present work is to experimentally study the effects of the oxygen gas flow rate and ion beam plasma conditions on the properties of indium molybdenum oxide (IMO) films deposited onto the polyethersulfone (PES) substrate. Crystal structure, surface morphology, and optoelectronic properties of IMO films are examined as a function of oxygen gas flow rate and ion beam discharge voltage. Experimental results show that the IMO films consist of a cubic bixbyite B-In 2 O 3 single phase with its crystal preferred orientation alone B(222). Mo 6+ ions are therefore considered to partially substitute In 3+ sites in the deposit. Under-controlled ion bombardment during deposition enhances the reaction among those arriving oxygen and metal ion species to condense into IMO film and facilitates a decreased surface roughness of IMO film. The film with ultimate crystallinity and the lowest surface roughness is obtained when the oxygen flow rate of 3 sccm and the discharge voltage of 110 V are employed. This results in the lowest electrical resistivity due mainly to the increased Hall mobility and irrelevant to carrier concentration. The lowest electrical resistivity of 8.63 x 10 -4 ohm-cm with a 84.63% transmittance at a wavelength of 550 nm can be obtained, which satisfies the requirement of a flexible transparent conductive polymer substrate

Impact on electronic structure of donor/acceptor blend in organic photovoltaics by decontamination of molybdenum-oxide surface

Science.gov (United States)

Ito, Yuta; Akaike, Kouki; Fukuda, Takeshi; Sato, Daisuke; Fuse, Takuya; Iwahashi, Takashi; Ouchi, Yukio; Kanai, Kaname

2018-05-01

Molybdenum oxide (MoOx) is widely used as the hole-transport layer in bulk-heterojunction organic photovoltaics (BHJ-OPVs). During the fabrication of solution-processed BHJ-OPVs on vacuum-deposited MoOx film, the film must be exposed to N2 atmosphere in a glove box, where the donor/acceptor blends are spin-coated from a mixed solution. Employing photoelectron spectroscopy, we reveal that the exposure of the MoOx film to such atmosphere contaminates the MoOx surface. Annealing the contaminated MoOx film at 160 °C for 5 min, prior to spin-coating the blend film, can partially remove the carbon and oxygen adsorbed on the MoOx surface during the exposure of MoOx. However, the contamination layer on the MoOx surface does not affect the energy-level alignment at the interface between MoOx and the donor/acceptor blend. Hence, significant improvement in the performance of BHJ-OPVs by mildly annealing the MoOx layer, which was previously reported, can be explained by the reduction of undesired contamination.

Tungsten and molybdenum with oxide dispersion, production and properties

International Nuclear Information System (INIS)

Haerdtle, S.; Schmidberger, R.

1989-01-01

By the reaction spray process metal powders with dispersed metal oxides can be produced in one step. The systems investigated here are tungsten and molybdenum with 0,5% resp. 5% La 2 O 3 , Y 2 O 3 and ZrO 2 . The oxides with diameters below 0,5μm are finely dispersed within the metal powder particles. The sinterability of the powders depends on the oxide content. Maximum density at an oxide content of 0,5% is about 96% at a sintering temperature of 1600 0 C. The type of oxide influences the densification versus temperature but not the final density. 5 refs., 11 figs. (Author)

Microstructure and emission ability of rare earth oxides doped molybdenum cathodes

International Nuclear Information System (INIS)

Yang Jiancan; Nie Zuoren; Wang Yiman

2003-01-01

We adopted high-resolution transmission electron microscopy (TEM) and scanning electron microscopy (SAM) to observe and analyze the microstructure of rare earth oxide (La 2 O 3 , Sc 2 O 3 ) doped molybdenum cathodes. The results show that there are many nanometer particles in the molybdenum matrix besides some sub-micrometer particles in the crystal interfaces. All these particles are rare earth oxides as determined through calculating the electron diffraction pattern. Then we determined the electron work function and the zero-field emission current of molybdenum cathodes by the electron emission measurement. To correlate the emission data with surface composition, we use Auger electron spectroscopy (AES) to analyze the elements on the activated cathode surface and their depth profiles. We found that there were about 20 nm thick layers on an activated cathode surface, which have a high content of rare earth elements. We also use AES to analyze the elements diffusion to the cathode surface from cathode body during heating up to its operating temperature to find out which element positively affects the electron emission

The properties of transparent conducting molybdenum-doped ZnO films grown by radio frequency magnetron sputtering

International Nuclear Information System (INIS)

Xiu Xian-Wu; Zhao Wen-Jing

2012-01-01

Transparent conducting molybdenum-doped zinc oxide films are prepared by radio frequency (RF) magnetron sputtering at ambient temperature. The MoO 3 content in the target varies from 0 to 5 wt%, and each film is polycrystalline with a hexagonal structure and a preferred orientation along the c axis. The resistivity first decreases and then increases with the increase in MoO 3 content. The lowest resistivity achieved is 9.2×10 −4 Ω·cm, with a high Hall mobility of 30 cm 2 ·V −1 ·s 1 and a carrier concentration of 2.3×10 20 cm −3 at an MoO 3 content of 2 wt%. The average transmittance in the visible range is reduced from 91% to 80% with the increase in the MoO 3 content in the target. (condensed matter: structural, mechanical, and thermal properties)

Adhesion Improvement and Characterization of Magnetron Sputter Deposited Bilayer Molybdenum Thin Films for Rear Contact Application in CIGS Solar Cells

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Weimin Li

2016-01-01

Full Text Available Molybdenum (Mo thin films are widely used as rear electrodes in copper indium gallium diselenide (CIGS solar cells. The challenge in Mo deposition by magnetron sputtering lies in simultaneously achieving good adhesion to the substrates while retaining the electrical and optical properties. Bilayer Mo films, comprising five different thickness ratios of a high pressure (HP deposited bottom layer and a low pressure (LP deposited top layer, were deposited on 40 cm × 30 cm soda-lime glass substrates by DC magnetron sputtering. We focus on understanding the effects of the individual layer properties on the resulting bilayer Mo films, such as microstructure, surface morphology, and surface oxidation. We show that the thickness of the bottom HP Mo layer plays a major role in determining the micromechanical and physical properties of the bilayer Mo stack. Our studies reveal that a thicker HP Mo bottom layer not only improves the adhesion of the bilayer Mo, but also helps to improve the film crystallinity along the preferred [110] direction. However, the surface roughness and the porosity of the bilayer Mo films are found to increase with increasing bottom layer thickness, which leads to lower optical reflectance and a higher probability for oxidation at the Mo surface.

Molybdenum oxide nanocubes: Synthesis and characterizations

Energy Technology Data Exchange (ETDEWEB)

Muthamizh, S.; Suresh, R.; Giribabu, K.; Manigandan, R.; Kumar, S. Praveen; Munusamy, S.; Narayanan, V., E-mail: vnnara@yahoo.co.in [Department of Inorganic Chemistry, University of Madras, Guindy Campus, Chennai -600025 (India); Stephen, A. [Department of Nuclear Physics, University of Madras, Guindy Campus, Chennai-600025 (India)

2015-06-24

Molybdenum oxide nanoparticles were prepared by Solid state synthesis. The MoO{sub 3} nanoparticles were synthesized by using commercially available ammonium heptamolybdate. The XRD pattern reveals that the synthesized MoO{sub 3} has orthorhombic structure. In addition, lattice parameter values were also calculated using XRD data. The Raman analysis confirm the presence of Mo-O in MoO{sub 3} nanoparticles. DRS-UV analysis shows that MoO{sub 3} has a band gap of 2.89 eV. FE-SEM analysis confirms the material morphology in cubes with nano scale.

Electrochromic properties of bipolar pulsed magnetron sputter deposited tungsten–molybdenum oxide films

Energy Technology Data Exchange (ETDEWEB)

Lin, Tai-Nan [Chemical Engineering Division, Institute of Nuclear Energy Research, Taoyuan 325, Taiwan, ROC (China); Lin, Yi Han; Lee, Chin Tan [Department of Electronic Engineering, National Quemoy University, Kinmen 892, Taiwan, ROC (China); Han, Sheng [Center of General Education, National Taichung Institute of Technology, Taichung 404, Taiwan, ROC (China); Weng, Ko-Wei, E-mail: kowei@nqu.edu.tw [Department of Electronic Engineering, National Quemoy University, Kinmen 892, Taiwan, ROC (China)

2015-06-01

There are great interests in electrochromic technology for smart windows and displays over past decades. In this study, the WMoO{sub x} thin films were deposited onto indium tin oxide glass and silicon substrates by pulsed magnetron sputter system with W and Mo targets. The films were deposited with fixed W target power while the variant parameter of Mo target power in the range 50, 100, 150 and 200 W was investigated. The working pressure was fixed at 1.33 Pa with a gas mixture of Ar (30 sccm) and O{sub 2} (15 sccm). The film thickness increased with the Mo target power. Higher plasma power resulted in a crystalline structure which would reduce the electrochromic property of the film. The influence of plasma powers applied to Mo target on the structural, optical and electrochromic properties of the WMoO{sub x} thin films has been investigated. WMoO{sub x} films grown at Mo target powers less than 100 W were found to be amorphous. The films deposited at 150 W, which is the optimal fabrication condition, exhibit better electrochromic properties with high optical modulation, high coloration efficiency and less color memory effect at wavelength 400, 550 and 800 nm. The improvement resulted from the effect of doping Mo has been tested. The maximum ΔT (%) values are 36.6% at 400 nm, 65.6% at 550 nm, and 66.6% at 800 nm for pure WO{sub 3} film. The addition of Mo content in the WMoO{sub x} films provides better resistance to the short wavelength light source and can be used in the concerned application. - Highlights: • WMoO{sub x} films are deposited by pulsed magnetron sputter with pure W and Mo targets. • Mo addition in WMoO{sub x} provides better resistance to short wavelength light source. • WMoO{sub x} films exhibit electrochemical stability in the cycling test.

Photoelectrochemical Cell of Hybrid Regioregular POLY(3-HEXYLTHIOPHENE-2,5-DIYL) and Molybdenum Disulfide Film

Science.gov (United States)

Abdelmola, Fatmaelzahraa M.; Ram, Manoj K.; Takshi, Arash; Stafanakos, Elias; Kumar, Ashok; Goswami, D. Yogi

The photoelectrochemical cell attracts attention worldwide due to conversion of optical energy into electricity, production of hydrogen through water splitting and use in photodetector and photo-sensor applications. We have been working on the photochemical cell based on regioregular polyhexylthiophenes hybrid-structured films for photoelectrochemical and photovoltaic applications. This paper discusses the hybrid film studies on regioregular poly(3-hexylthiophene-2,5-diyl) (P3HT) with 2D molybdenum disulfide (MoS2) for photoelectrochemical cell. The hybrid P3HT/MoS2 films deposited over indium tin oxide (ITO)-coated glass plate or n-type silicon substrates were characterized using FTIR, UV/vis, electrochemical and scanning electron microscopy (SEM) techniques. The optical measurements showed a higher absorption magnitude with low reflection properties of P3HT/MoS2 hybrid films revealing a superior photocurrent compared to both P3HT and MoS2 films. The P3HT/MoS2 hybrid-based photoelectrochemical cell yielded a short-circuit current (Isc) of 183.16μAṡcm-2, open-circuit voltage (Voc) of 0.92V, fill factor (FF) of 25% and power conversion efficiency (η) of 0.18% under the light intensity of 242Wṡm-2. The estimated power conversion efficiency and fill factor are comparable to organic-based photovoltaic devices.

Type II textured molybdenum disulphide films produced by direct vapour transport and rf-magnetron sputtering

International Nuclear Information System (INIS)

Bohlken, S.F.; Lemon, K.D.; Jakovidis, G.; Taheri, E.H.

1999-01-01

Full text: Molybdenum disulphide (MoS 2 ) is one of the few naturally occurring Layered Transition Metal Dichalcogenides and is the primary source for elemental molybdenum. It displays exceptional lubrication performance in both vacuum and atmospheric conditions over a wide temperature range. An important emerging application of MoS 2 and related materials is photovoltaics. Films of MoS 2 exhibit several morphologies described by the orientation of platelets with respect to the substrate. Films with platelets perpendicular or parallel to the substrate are referred to by their morphology, which is type-I or type-II respectively. Production of exclusive type-II films is highly desirable in applications involving lubrication and photovoltaics. For example, type-II morphology reduces friction and minority carrier recombination centres, thus improving tribological and photovoltaic performance. We have successfully produced type-II films using both direct vapour transport and rf-magnetron sputtering Continuous polycrystalline films (∼ 10 μm thick) grown in our laboratory using vapour transport have typical areas 1000 mm 2 . A novel ejecta filtration technique was applied to rf-magnetron sputtering. Films produced using this approach retain exclusive type-II morphology at thicknesses where type-I would normally be observed (∼ 200nm)

Molybdenum oxide nanocolloids prepared by an external field-assisted laser ablation in water

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Spadaro Salvatore

2018-01-01

Full Text Available he synthesis of extremely stable molybdenum oxide nanocolloids by pulsed laser ablation was studied. This green technique ensures the formation of contaminant-free nanostructures and the absence of by-products. A focused picosecond pulsed laser beam was used to ablate a solid molybdenum target immersed in deionized water. Molybdenum oxide nearly spherical nanoparticles with dimensions within few nanometers (20-100 nm are synthesized when the ablation processes were carried out, in water, at room temperature and 80°C. The application of an external electric field during the ablation process induces a nanostructures reorganization, as indicated by Scanning-Transmission Electron Microscopy images analysis. The ablation products were also characterized by some spectroscopic techniques: conventional UV-vis optical absorption, atomic absorption, dynamic light scattering, micro-Raman and X-ray photoelectron spectroscopies. Finally, NIH/3T3 mouse fibroblasts were used to evaluate cell viability by the sulforhodamine B assay

Deposition and characterization of ZrMoN thin films by reactive magnetron sputtering

International Nuclear Information System (INIS)

Fontes Junir, A.S.; Felix, L.C.; Oliveira, G.B. de; Fernandez, D.R.; Carvalho, R.G.; Tentardini, E.K.; Silva Junior, A.H. da

2016-01-01

Thin films of ZrMoN were deposited by magnetron reactive sputtering technique in order to study the molybdenum influence on the mechanical properties and oxidation resistance of these coatings. Three thin films with molybdenum concentrations from 25 to 40 at.% were selected. The displacement of characteristic peaks of ZrN where identified by GIXRD results of films with larger Mo content. This result is indicative of the Mo accommodation in the lattice structure. Hardness tests revealed favorable results with values up to 33 GPa. Oxidation tests showed that ZrN oxidized at 500 °C with a monoclinic ZrO 2 and tetragonal formation; whereas the thin films with Mo addition impeded the formation of the monoclinic ZrO 2 phase at partial oxidation. (author)

Adhesion analysis of polycrystalline diamond films on molybdenum by means of scratch, indentation and sand abrasion testing

NARCIS (Netherlands)

Buijnsters, J.G.; Shankar, P.; Enckevort, W.J.P. van; Schermer, J.J.; Meulen, J.J. ter

2005-01-01

Diamond films have been grown by hot-filament chemical vapour deposition (CVD) on molybdenum substrates under different growth conditions. The films grown with increasing substrate temperatures show a higher interconnection of diamond grains, whereas increasing methane concentrations in the 0.5-4.0%

Sulfidation of alumina-supported iron and iron-molybdenum oxide catalysts

NARCIS (Netherlands)

Ramselaar, W.L.T.M.; Crajé, M.W.J.; Hadders, R.H.; Gerkema, E.; Beer, de V.H.J.; Kraan, van der A.M.

1990-01-01

The transition of alumina-supported iron and iron-molybdenum catalysts from the oxidic precursor to the sulfided catalysts was systematically studied by means of in-situ Mössbauer spectroscopy at room temperature. This enabled the adjudgement of various sulfidic phases in the sulfided catalysts. The

Effect of thermal treatment conditions on properties of vanadium molybdenum oxide catalyst in acrolein oxidation reaction to acrylic acid

International Nuclear Information System (INIS)

Gorshkova, T.P.; Tarasova, D.V.; Olen'kova, I.P.; Andrushkevich, T.V.; Nikoro, T.A.

1984-01-01

The effect of thermal treatment conditions (temperature and gas medium) on properties of vanadium molybdenum oxide catalyst in acrolein oxidation reaction to acrylic acid is investigated. It is shown that active and selective catalysts are formed in the course of thermal decomposition of the drying product of ammonium metavanadate and paramolybdate under the conditions ensuring the vanadium ion reduction up to tetravalent state with conservation of molybdenum oxidation degree equal to 6. It is possible to realize it either by treatment of the catalyst calcinated in the air flow at 300 deg by the reaction mixture at the activation stage or by gas-reducer flow treatment at 280 deg. Thermal treatment in the reducing medium of the oxidized catalyst does not lead to complete regeneration of its properties

Synthesis and characterization of DC magnetron sputtered nano structured molybdenum thin films

Energy Technology Data Exchange (ETDEWEB)

Rondiya, S. R.; Rokade, A. V.; Jadhavar, A. A.; Pandharkar, S. M.; Kulkarni, R. R.; Karpe, S. D.; Diwate, K. D. [School of Energy Studies, Savitribai Phule Pune University, Pune 411007 (India); Jadkar, S. R., E-mail: sandesh@physics.unipune.ac.in [Department of Physics, Savitribai Phule Pune University, Pune 411007 (India)

2016-04-13

Molybdenum (Mo) thin films were deposited on corning glass (#7059) substrates using DC magnetron sputtering system. The effect of substrate temperature on the structural, morphology and topological properties have been investigated. Films were characterized by variety of techniques such as low angle x-ray diffraction (low angle XRD), field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM). The low angle XRD analysis revealed that the synthesized Mo films are nanocrystalline having cubic crystal structure with (110) preferential orientation. The microstructure of the deposited Mo thin films observed with FE-SEM images indicated that films are homogeneous and uniform with randomly oriented leaf shape morphology. The AFM analysis shows that with increase in substrate temperature the rms roughness of Mo films increases. The obtained results suggest that the synthesized nanostructured Mo thin films have potential application as a back contact material for high efficiency solar cells like CdTe, CIGS, CZTS etc.

Gel Fabrication of Molybdenum “Beads”

Energy Technology Data Exchange (ETDEWEB)

Lowden, Richard Andrew [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division; Armstrong, Beth L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division; Cooley, Kevin M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division

2016-11-01

Spherical molybdenum particles or “beads” of various diameters are of interest as feedstock materials for the additive manufacture of targets and assemblies used in the production of ⁹⁹Mo medical isotopes using accelerator technology. Small metallic beads or ball bearings are typically fabricated from wire; however, small molybdenum spheres cannot readily be produced in this manner. Sol-gel processes are often employed to produce small dense microspheres of metal oxides across a broad diameter range that in the case of molybdenum could be reduced and sintered to produce metallic spheres. These Sol-gel type processes were examined for forming molybdenum oxide beads; however, the molybdenum trioxide was chemically incompatible with commonly used gelation materials. As an alternative, an aqueous alginate process being assessed for the fabrication of oxide spheres for catalyst applications was employed to form molybdenum trioxide beads that were successfully reduced and sintered to produce small molybdenum spheres.

Synthesis, characterization and structural control of nano crystalline molybdenum oxide MoO{sub 3} single phase by low cost technique

Energy Technology Data Exchange (ETDEWEB)

Afify, H.H.; Hassan, S.A. [Solid State Department, Physics Division, National Research Centre, 33 El Bohouthst. (fromer El Tahrirst.), Dokki, P.O. 12622, Giza (Egypt); Abouelsayed, A., E-mail: as.abouelsayed@gmail.com [Spectroscopy Department, Physics Division, National Research Centre, 33 El Bohouthst. (fromer El Tahrirst.), Dokki, P.O. 12622, Giza (Egypt); Demian, S.E. [Solid State Department, Physics Division, National Research Centre, 33 El Bohouthst. (fromer El Tahrirst.), Dokki, P.O. 12622, Giza (Egypt); Zayed, H.A. [Physics Department, Faculty of Girls for Art, Sciences and Education, Ain Shams University (Egypt)

2016-06-15

Thermodynamically stable α- MoO{sub 3} thin film is prepared without any other phases of the molybdenum oxides. Simple and low coast spray pyrolysis technique is used. Growth conditions are optimized to produce pure α- MoO{sub 3} with controlled crystallite size and surface morphology. Small angle (GAXRD) diffractometer is used to elucidate the structure. Profile shape function (PSF) model is made for the experimental data. WinFit software is going first to fit (PSF) to use the refined profile parameters for determination of crystallite size and internal residual strain. The (GAXRD) patterns prove the existence of α- MoO{sub 3} only with layered structure, indicated by the appearance of only (0k0). The calculated crystallite sizes and the strain are found to range from 10 to 28 nm and 0.28%–0.05% respectively. Ultraviolet and Visible transmission measurements were performed over a wavelength range 190–2500 nm on the MoO{sub 3} thin films synthesized by spray pyrolysis technique at different substrate temperature. The two sub-bands corresponds to the electronic transition between the molybdenum oxidation states Mo{sup 4+}, Mo{sup 5+} and Mo{sup 6+} are observed. Quantitative information on the temperature-induced blue shift of the sub-bands was obtained by fitting the spectra with Lorentz functions. The transition from Mo{sup 5+} to Mo{sup 6+} oxidation states show a blue shift up to Tc = 325 °C. Above Tc, the transition Mo{sup 5+} to Mo{sup 6+} increases more drastically, resulting in an anomaly in the temperature-induced shift at Tc. The anomaly can be attributed to the amorphous-to-crystalline phase transition at 325 °C. In addition, both refractive index and extinction coefficient are calculated as a function of substrate temperature. - Highlights: • Single phase α-MoO{sub 3} nano crystalline MoO{sub 3} thin films have been synthesized. • Amorphous-to-crystalline phase transition occurs at 325 °C for MoO{sub 3} thin films. • A clear

REACTION PRODUCTS AND CORROSION OF MOLYBDENUM ELECTRODE IN GLASS MELT CONTAINING ANTIMONY OXIDES AND SODIUM SULFATE

Directory of Open Access Journals (Sweden)

JIŘÍ MATĚJ

2012-09-01

Full Text Available The products on the interface of a molybdenum electrode and glass melt were investigated primarily at 1400°C in three model glass melts without ingredients, with 1 % Sb2O3 and with 1 % Sb2O3 and 0.5 % SO3 (wt. %, both under and without load by alternating current. Corrosion of the molybdenum electrode in glass melt without AC load is higher by one order of magnitude if antimony oxides are present. The corrosion continues to increase if sulfate is present in addition to antimony oxides. Isolated antimony droplets largely occur on the electrode-glass melt interface, and numerous droplets are also dissipated in the surrounding glass if only antimony oxides are present in the glass melt. A comparatively continuous layer of antimony occurs on the interface if SO3 is also present, antimony being always in contact with molybdenum sulfide. Almost no antimony droplets are dissipated in the glass melt. The total amount of precipitated antimony also increases. The presence of sulfide on the interface likely facilitates antimony precipitation. The reaction of molybdenum with antimony oxides is inhibited in sites covered by an antimony layer. The composition of sulfide layers formed at 1400°C approximates that of Mo2S3. At 1100°C, the sulfide composition approximates that of MoS4. Corrosion multiplies in the glass melt without additions through the effect of AC current, most molybdenum being separated in the form of metallic particles. Corrosion also increases in the glass melt containing antimony oxides. This is due to increased corrosion in the neighborhood of the separated antimony droplets. This mechanism also results in the loosening of molybdenum particles. The amount of precipitated antimony also increases through the effect of the AC current. AC exerts no appreciable effect on either corrosion, the character of the electrode-glass interface, or antimony precipitation in the glass melt containing SO3.

Development of Silicide Coating on Molybdenum Alloy Cladding

International Nuclear Information System (INIS)

Lim, Woojin; Ryu, Ho Jin

2015-01-01

The molybdenum alloy is considered as one of the accident tolerant fuel (ATF) cladding materials due to its high temperature mechanical properties. However, molybdenum has a weak oxidation resistance at elevated temperatures. To modify the oxidation resistance of molybdenum cladding, silicide coating on the cladding is considered. Molybdenum silicide layers are oxidized to SiO 2 in an oxidation atmosphere. The SiO 2 protective layer isolates the substrate from the oxidizing atmosphere. Pack cementation deposition technique is widely adopted for silicide coating for molybdenum alloys due to its simple procedure, homogeneous coating quality and chemical compatibility. In this study, the pack cementation method was conducted to develop molybdenum silicide layers on molybdenum alloys. It was found that the Mo 3 Si layer was deposited on substrate instead of MoSi 2 because of short holding time. It means that through the extension of holding time, MoSi 2 layer can be formed on molybdenum substrate to enhance the oxidation resistance of molybdenum. The accident tolerant fuel (ATF) concept is to delay the process following an accident by reducing the oxidation rate at high temperatures and to delay swelling and rupture of fuel claddings. The current research for Atf can be categorized into three groups: First, modification of existing zirconium-based alloy cladding by improving the high temperature oxidation resistance and strength. Second, replacing Zirconium based alloys with alternative metallic materials such as refractory elements with high temperature oxidation resistance and strength. Third, designing alternative fuel structures using ceramic and composite systems

Multifunctional Interlayer Based on Molybdenum Diphosphide Catalyst and Carbon Nanotube Film for Lithium-Sulfur Batteries.

Science.gov (United States)

Luo, Yufeng; Luo, Nannan; Kong, Weibang; Wu, Hengcai; Wang, Ke; Fan, Shoushan; Duan, Wenhui; Wang, Jiaping

2018-02-01

A multifunctional interlayer, composed of molybdenum diphosphide (MoP 2 ) nanoparticles and a carbon nanotube (CNT) film, is introduced into a lithium-sulfur (Li-S) battery system to suppress polysulfide migration. Molybdenum diphosphide acts as the catalyst and can capture polysulfides and improve the polysulfide conversion activity during the discharge/charge processes. The CNT film acts as a conductive skeleton to support the MoP 2 nanoparticles and to ensure their uniform distribution. The CNT film physically hinders polysulfide migration, acts as a current collector, and provides abundant electron pathways. The Li-S battery containing the multifunctional MoP 2 /CNT interlayer exhibits excellent electrochemical performance. It delivers a reversible specific capacity of 905 mA h g -1 over 100 cycles at 0.2 C, with a capacity decay of 0.152% per cycle. These results suggest the introduction of the multifunctional CNT/MoP 2 interlayer as an effective and practical method for producing high-performance Li-S batteries. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Crystalline Molybdenum Oxide Thin-Films for Application as Interfacial Layers in Optoelectronic Devices

DEFF Research Database (Denmark)

Fernandes Cauduro, André Luis; dos Reis, Roberto; Chen, Gong

2017-01-01

The ability to control the interfacial properties in metal-oxide thin films through surface defect engineering is vital to fine-tune their optoelectronic properties and thus their integration in novel optoelectronic devices. This is exemplified in photovoltaic devices based on organic, inorganic...... or hybrid technologies, where precise control of the charge transport properties through the interfacial layer is highly important for improving device performance. In this work, we study the effects of in situ annealing in nearly stoichiometric MoOx (x ∼ 3.0) thin-films deposited by reactive sputtering. We...... with structural characterizations, this work addresses a novel method for tuning, and correlating, the optoelectronic properties and microstructure of device-relevant MoOx layers....

Purifications of calcium carbonate and molybdenum oxide powders for neutrinoless double beta decay experiment, AMoRE

International Nuclear Information System (INIS)

Park, HyangKyu

2015-01-01

The AMoRE (Advanced Mo based Rare process Experiment) collaboration is going to use calcium molybdate crystals to search for neutrinoless double beta decay of 100 Mo isotope. In order to make the crystal, we use calcium carbonate and molybdenum oxide powders as raw materials. Therefore it is highly necessary to reduce potential sources for radioactive backgrounds such as U and Th in the powders. In this talk, we will present our studies for purification of calcium carbonate and molybdenum oxide powders

Electrochemical deposition of molybdenum sulfide thin films on conductive plastic substrates as platinum-free flexible counter electrodes for dye-sensitized solar cells

Energy Technology Data Exchange (ETDEWEB)

Cheng, Chao-Kuang; Hsieh, Chien-Kuo, E-mail: jack_hsieh@mail.mcut.edu.tw

2015-06-01

In this study, pulsed electrochemical deposition (pulsed ECD) was used to deposit molybdenum sulfide (MoS{sub x}) thin films on indium tin oxide/polyethylene naphthalate (ITO/PEN) substrates as flexible counter electrodes (CEs) for dye-sensitized solar cells (DSSCs). The surface morphologies and elemental distributions of the prepared MoS{sub x} thin films were examined using field-emission scanning electron microscope (FE-SEM) equipped with energy-dispersive X-ray spectroscopy. The chemical states and crystallinities of the prepared MoS{sub x} thin films were examined by X-ray photoelectron spectroscopy and X-ray diffraction, respectively. The optical transmission (T (%)) properties of the prepared MoS{sub x} samples were determined by ultraviolet–visible spectrophotometry. Cyclic voltammetry (CV) and Tafel-polarization measurements were performed to analyze the electrochemical properties and catalytic activities of the thin films for redox reactions. The FE-SEM results showed that the MoS{sub x} thin films were deposited uniformly on the ITO/PEN flexible substrates via the pulsed ECD method. The CV and Tafel-polarization curve measurements demonstrated that the deposited MoS{sub x} thin films exhibited excellent performances for the reduction of triiodide ions. The photoelectric conversion efficiency (PCE) of the DSSC produced with the pulsed ECD MoS{sub x} thin-film CE was examined by a solar simulator. In combination with a dye-sensitized TiO{sub 2} working electrode and an iodine-based electrolyte, the DSSC with the MoS{sub x} flexible CE showed a PCE of 4.39% under an illumination of AM 1.5 (100 mW cm{sup −2}). Thus, we report that the MoS{sub x} thin films are active catalysts for triiodide reduction. The MoS{sub x} thin films are prepared at room temperature and atmospheric pressure and in a simple and rapid manner. This is an important practical contribution to the production of flexible low-cost thin-film CEs based on plastic substrates. The MoS{sub x

Hydrothermal synthesis of electrode materials pyrochlore tungsten trioxide film

Science.gov (United States)

Guo, Jingdong; Li, Yingjeng James; Stanley Whittingham, M.

Hydrothermal synthesis methods have been successfully used to prepare new transition-metal oxides for cathodes in electrochemical devices such as lithium batteries and electrochromic windows. The tungsten oxides were the first studied, but the method has been extended to the oxides of molybdenum, vanadium and manganese. Sodium tungsten oxide films with the pyrochlore structure have been prepared on gold/alumina and indium-doped tin oxide substrates. These films reversibly and rapidly intercalate lithium and hydrogen ions.

Controlled optical properties via chemical composition tuning in molybdenum-incorporated β-Ga2O3 nanocrystalline films

Science.gov (United States)

Battu, Anil K.; Manandhar, S.; Shutthanandan, V.; Ramana, C. V.

2017-09-01

An approach is presented to design refractory-metal incorporated Ga2O3-based materials with controlled structural and optical properties. The molybdenum (Mo)-content in Ga2O3 was varied from 0 to 11 at% in the sputter-deposited Ga-Mo-O films. Molybdenum was found to significantly affect the structure and optical properties. While low Mo-content (≤4 at%) results in the formation of single-phase (β-Ga2O3), higher Mo-content results in amorphization. Chemically-induced band gap variability (Eg ∼ 1 eV) coupled with structure-modification indicates the electronic-structure changes in Ga-Mo-O. The linear relationship between chemical-composition and optical properties suggests that tailoring the optical-quality and performance of Ga-Mo-O films is possible by tuning the Mo-content.

Separation of 99Tc from irradiated molybdenum oxide by extraction with trioctilamine

International Nuclear Information System (INIS)

Carvalho, O.G. de.

1979-01-01

A separation method of sup( 99 m)Tc, from irradiated molybdenum oxide, by extraction with trioctilamino in 1,2 dichloroethane, 2% v/v is studied. Two preliminary studies are done: 1) Stablishment of the shaking time necessary to reach the equilibrium between the organic and the aqueous phase; 2) Choice of the concentration of solution of TOA in 1,2 dichloroethane to obtain the best separation conditions of sup( 99 m)Tc. After stablishing these two parameters, the study of extraction in solutions of hydrochloric nitric and sulfuric acids in different concentrations is done, followed by the study of the variation of extraction percentage of sup( 99 m)Tc in relation to the molybdenum oxide mass and the back-extraction of sup( 99 m)Tc to the aqueous phase with solutions of perchloric acid 1,0 and 0,1 N and ammonium hydroxide 1,0 N. (Author) [pt

Turnover of texture in low rate sputter-deposited nanocrystalline molybdenum films

International Nuclear Information System (INIS)

Druesedau, T.P.; Klabunde, F.; Loehmann, M.; Hempel, T.; Blaesing, J.

1997-01-01

The crystallite size and orientation in molybdenum films prepared by magnetron sputtering at a low rate of typical 1 (angstrom)s and a pressure of 0.45 Pa was investigated by X-ray diffraction and texture analysis. The surface topography was studied using atomic force microscopy. Increasing the film thickness from 20 nm to 3 microm, the films show a turnover from a (110) fiber texture to a (211) mosaic-like texture. In the early state of growth (20 nm thickness) the development of dome-like structures on the surface is observed. The number of these structures increases with film thickness, whereas their size is weakly influenced. The effect of texture turnover is reduced by increasing the deposition rate by a factor of six, and it is absent for samples mounted above the center of the magnetron source. The effect of texture turnover is related to the bombardment of the films with high energetic argon neutrals resulting from backscattering at the target under oblique angle and causing resputtering. Due to the narrow angular distribution of the reflected argon, bombardment of the substrate plane is inhomogeneous and only significant for regions close to the erosion zone of the magnetron

Sputtered molybdenum thin films and the application in CIGS solar cells

Energy Technology Data Exchange (ETDEWEB)

Zhou, D.; Zhu, H., E-mail: hongbing1982@hotmail.com; Liang, X.; Zhang, C.; Li, Z.; Xu, Y.; Chen, J.; Zhang, L.; Mai, Y., E-mail: yaohuamai@hbu.edu.cn

2016-01-30

Graphical abstract: - Highlights: • Mo thin films are prepared by magnetron sputtering. • The dynamic deposition rate increases with the increasing discharge power. • The surface structure of Mo films varies with discharge power and working pressure. • High efficiency CIGS thin film solar cell of 15.2% has been obtained. - Abstract: Molybdenum (Mo) thin films are prepared by magnetron sputtering with different discharge powers and working pressures for the application in Cu(In, Ga)Se{sub 2} (CIGS) thin film solar cells as back electrodes. Properties of these Mo thin films are systematically investigated. It is found that the dynamic deposition rate increases with the increasing discharge power while decreases with the increasing working pressure. The highest dynamic deposition rate of 15.1 nm m/min is achieved for the Mo thin film deposited at the discharge power of 1200 W and at the working pressure of 0.15 Pa. The achieved lowest resistivity of 3.7 × 10{sup −5} Ω cm is attributed to the large grains in the compact thin film. The discharge power and working pressure have great influence on the sputtered Mo thin films. High efficiency of 12.5% was achieved for the Cu(In, Ga)Se{sub 2} (CIGS) thin film solar cells with Mo electrodes prepared at 1200 W and low working pressures. By further optimizing material and device properties, the conversion efficiency has reached to 15.2%.

Hardness enhancement and oxidation resistance of nanocrystalline TiN/Mo xC multilayer films

International Nuclear Information System (INIS)

Liu, Q.; Wang, X.P.; Liang, F.J.; Wang, J.X.; Fang, Q.F.

2006-01-01

In this paper the influence of the layer's microstructure on the hardness enhancement in multilayer nanocrystalline films and the oxidation resistance are studied. The TiN/Mo x C multilayer films at different modulation period, and Mo x C and TiN monolayer films were deposited on the (0 0 1) silicon wafers and molybdenum sheets by rf and dc magnetron sputtering. The monolayer TiN films with a thickness of about 2 μm are of pure face-center cubic TiN phase, while the monolayer Mo x C films consist of two phases, one of which is body-center cubic Mo and the other is hexagonal Mo 2 C as determined by XRD. The coarse columnar grains of about 200 nm in the monolayer TiN films become much smaller or disappear in the multilayer films. The hardness enhancement of the multilayer films takes place at the modulation period of 320 nm, which can reach to 26 GPa and is much higher than the values of Mo x C and TiN monolayer films. This enhancement in hardness can be explained as the decrease in the size and/or disappearance of columnar grains in the TiN layer. The Young's modulus in the temperature range from 100 to 400 deg. C increases with decreasing modulation period. It is found that about 100 nm thick TiN films can increase largely the oxidation resistance of Mo x C films

Tc depression and superconductor-insulator transition in molybdenum nitride thin films

Science.gov (United States)

Ichikawa, F.; Makise, K.; Tsuneoka, T.; Maeda, S.; Shinozaki, B.

2018-03-01

We have studied that the Tc depression and the superconductor-insulator transition (SIT) in molybdenum nitride (MoN) thin films. Thin films were fabricated by reactive DC magnetron sputtering method onto (100) MgO substrates in the mixture of Ar and N2 gases. Several dozen MoN thin films were prepared in the range of 3 nm < thickness d < 60 nm. The resistance was measured by a DC four-probe technique. It is found that Tc decreases from 6.6 K for thick films with increase of the normal state sheet resistance {R}{{sq}}{{N}} and experimental data were fitted to the Finkel’stein formula using the bulk superconducting transition temperature Tc 0 = 6.45 K and the elastic scattering time of electron τ = 1.6 × 10‑16 s. From this analysis the critical sheet resistance Rc is found about 2 kΩ, which is smaller than the quantum sheet resistance R Q. This value of Rc is almost the same as those for 2D NbN films. The value of τ for MoN films is also the similar value for NbN films 1.0 × 10‑16 s, while Tc 0 is different from that for NbN films 14.85 K. It is indicated that the mechanism of SIT for MoN films is similar to that of NbN films, while the mean free path ℓ for MoN films is larger than that for NbN films.

Oxide ultrathin films science and technology

CERN Document Server

Pacchioni, Gianfranco

2012-01-01

A wealth of information in one accessible book. Written by international experts from multidisciplinary fields, this in-depth exploration of oxide ultrathin films covers all aspects of these systems, starting with preparation and characterization, and going on to geometrical and electronic structure, as well as applications in current and future systems and devices. From the Contents: Synthesis and Preparation of Oxide Ultrathin Films Characterization Tools of Oxide Ultrathin Films Ordered Oxide Nanostructures on Metal Surfaces Unusual Properties of Oxides and Other Insulators in the Ultrathin Limit Silica and High-K Dielectrics Thin Films in Microelectronics Oxide Passive Films and Corrosion Protection Oxide Films as Catalytic Materials and as Models of Real Catalysts Oxide Films in Spintronics Oxide Ultrathin Films in Solid Oxide Fuel Cells Transparent Conducting and Chromogenic Oxide Films as Solar Energy Materials Oxide Ultrathin Films in Sensor Applications Ferroelectricity in Ultrathin Film Capacitors T...

Molybdenum dioxide-molybdenite roasting

International Nuclear Information System (INIS)

Sabacky, B.J.; Hepworth, M.T.

1984-01-01

A process is disclosed for roasting molybdenite concentrates directly to molybdenum dioxide. The process comprises establishing a roasting zone having a temperature of about 700 0 C. to about 800 0 C., introducing into the roasting zone particulate molybdenum dioxide and molybdenite in a weight ratio of at least about 2:1 along with an oxygen-containing gas in amount sufficient to oxidize the sulfur content of the molybdenite to molybdenum dioxide

Atomic layer deposition of molybdenum disulfide films using MoF ₆ and H ₂ S

Energy Technology Data Exchange (ETDEWEB)

Mane, Anil U. [Energy Systems Division, Argonne National Laboratory, 9700 S. Cass Ave., Argonne, Illinois 60439; Letourneau, Steven [Micron School of Materials Science and Engineering, Boise State University, 1910 University Dr., Boise, Idaho 83725; Mandia, David J. [Energy Systems Division, Argonne National Laboratory, 9700 S. Cass Ave., Argonne, Illinois 60439; Liu, Jian [Department of Chemistry, Northwestern University, 2145 Sheridan Rd., Evanston, Illinois 60208; Libera, Joseph A. [Energy Systems Division, Argonne National Laboratory, 9700 S. Cass Ave., Argonne, Illinois 60439; Lei, Yu [Energy Systems Division, Argonne National Laboratory, 9700 S. Cass Ave., Argonne, Illinois 60439; Peng, Qing [Energy Systems Division, Argonne National Laboratory, 9700 S. Cass Ave., Argonne, Illinois 60439; Graugnard, Elton [Micron School of Materials Science and Engineering, Boise State University, 1910 University Dr., Boise Idaho 83725; Elam, Jeffrey W. [Energy Systems Division, Argonne National Laboratory, 9700 S. Cass Ave, Argonne, Illinois 60439

2018-01-01

Molybdenum sulfide films were grown by atomic layer deposition on silicon and fused silica substrates using molybdenum hexafluoride (MoF6) and hydrogen sulfide at 200 degrees C. In situ quartz crystal microbalance (QCM) measurements confirmed linear growth at 0.46 angstrom/cycle and self-limiting chemistry for both precursors. Analysis of the QCM step shapes indicated that MoS2 is the reaction product, and this finding is supported by x-ray photoelectron spectroscopy measurements showing that Mo is predominantly in the Mo(IV) state. However, Raman spectroscopy and x-ray diffraction measurements failed to identify crystalline MoS2 in the as-deposited films, and this might result from unreacted MoFx residues in the films. Annealing the films at 350 degrees C in a hydrogen rich environment yielded crystalline MoS2 and reduced the F concentration in the films. Optical transmission measurements yielded a bandgap of 1.3 eV. Finally, the authors observed that the MoS2 growth per cycle was accelerated when a fraction of the MoF6 pulses were substituted with diethyl zinc. Published by the AVS

Interface modification of organic photovoltaics by combining molybdenum oxide (MoO{sub x}) and molecular template layer

Energy Technology Data Exchange (ETDEWEB)

Duan, Haichao [Institute of Super-microstructure and Ultrafast Process in Advanced Materials, School of Physics and Electronics, Central South University, Changsha, Hunan 410083 (China); Hunan Key Laboratory for Super-microstructure and Ultrafast Process, School of Physics and Electronics, Central South University, Changsha, Hunan 410083 (China); Yang, Junliang, E-mail: junliang.yang@csu.edu.cn [Institute of Super-microstructure and Ultrafast Process in Advanced Materials, School of Physics and Electronics, Central South University, Changsha, Hunan 410083 (China); Hunan Key Laboratory for Super-microstructure and Ultrafast Process, School of Physics and Electronics, Central South University, Changsha, Hunan 410083 (China); Fu, Lin; Xiong, Jian; Yang, Bingchu; Ouyang, Jun; Zhou, Conghua; Huang, Han [Institute of Super-microstructure and Ultrafast Process in Advanced Materials, School of Physics and Electronics, Central South University, Changsha, Hunan 410083 (China); Hunan Key Laboratory for Super-microstructure and Ultrafast Process, School of Physics and Electronics, Central South University, Changsha, Hunan 410083 (China); Gao, Yongli [Institute of Super-microstructure and Ultrafast Process in Advanced Materials, School of Physics and Electronics, Central South University, Changsha, Hunan 410083 (China); Hunan Key Laboratory for Super-microstructure and Ultrafast Process, School of Physics and Electronics, Central South University, Changsha, Hunan 410083 (China); Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627 (United States)

2015-01-01

We report discrete heterojunction small molecular organic photovoltaics (OPVs) with enhanced performance by modifying the interface using molybdenum oxide (MoO{sub x}) and molecular template layer perylene-3,4,9,10-tetracarboxylic-3,4,9,10-dianhydride (PTCDA). A large increase in open-circuit voltage was obtained in copper phthalocyanine/fullerene, i.e., CuPc/C{sub 60} and CuPc/PCBM, discrete planar heterojunction photovoltaics with an insertion of 5 nm MoO{sub x} hole transport layer at the interface between the anode electrode and the CuPc donor layer. It results from the band bending at the interface and the pinning of the highest occupied molecular orbital level of CuPc to the Fermi level of MoO{sub x} due to the defect states (oxygen vacancies) in MoO{sub x} thin films. Moreover, the short-circuit current showed an efficient improvement by inserting a 1 nm PTCDA layer at the interface between the MoO{sub x} layer and the CuPc layer. The PTCDA layer induces the growth of CuPc thin film with lying-down molecular arrangement, supporting the charge transports along the vertical direction. The power conversion efficiencies of CuPc/C{sub 60} and CuPc/PCBM discrete planar heterojunction photovoltaic devices were improved from about 0.80% to 1.50% with inserting both MoO{sub x} and PTCDA layers. The results suggest that the performance of organic discrete planar heterojunction photovoltaics could be optimized by interface modification with combining hole transport layer and molecular template layer, which are potentially suitable for other highly efficient OPVs, such as small molecular tandem OPVs. - Highlights: • Organic small molecule photovoltaics were fabricated by interface modification. • An inserted molybdenum oxide layer largely enhances open-circuit voltage. • An inserted molecular template layer dramatically improves short-circuit current. • The power conversion efficiencies are almost doubled with interface modification.

The passive oxide films growth on 316L stainless steel in borate buffer solution measured by real-time spectroscopic ellipsometry

Energy Technology Data Exchange (ETDEWEB)

Xu, Haisong; Wang, Lu; Sun, Dongbai [National Center for Materials Service Safety (NCMS), University of Science and Technology Beijing, Beijing 100083 (China); Yu, Hongying, E-mail: hyyu@ustb.edu.cn [Institute of Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083 (China)

2015-10-01

Highlights: • The optical properties of passive oxide films on 316L stainless steel were studied. • The thickness of the oxide films (1.5–2.6 nm) increased linearly with the potentials. • The growth of passive film followed high electric field ion conduction model. • Selective solubility of oxide induced compositional change of passive film. - Abstract: Passive film growth on 316L stainless steel was investigated in borate buffer electrolyte (pH = 9.1) by real-time spectroscopic ellipsometry (SE) and the composition was estimated by X-ray photoelectron spectroscopy (XPS). Anodic passivation of 316L SS was carried out in the potential range from 0 V{sub SCE} to 0.9 V{sub SCE}, after potentiostatic polarization for 1800s, the current density decayed from 10{sup −2} A cm{sup −2} to 10{sup −6} A cm{sup −2}. The passive film thickness was simulated from Frenel and Drude reflection equations, the average complex refractive index was assumed to be N = 2.3 − j0.445. The estimated thickness increased linearly with potential from 1.5 nm at 0 V to 2.6 nm at 0.8 V. The growth of passive film followed high electric field ion conduction model. The passive film mainly contained the oxide/hydroxide of iron and chromium. The selective solubility of oxide in passive film explained the change of iron and chromium content at different potentials. Few nickel and molybdenum also contributed to the passive film with a constant content.

Method for preparing microstructure arrays on the surface of thin film material

KAUST Repository

Wang, Peng; Tang, Bo; Zhang, Lianbin

2017-01-01

Methods are provided for growing a thin film of a nanoscale material. Thin films of nanoscale materials are also provided. The films can be grown with microscale patterning. The method can include vacuum filtration of a solution containing the nanostructured material through a porous substrate. The porous substrate can have a pore size that is comparable to the size of the nanoscale material. By patterning the pores on the surface of the substrate, a film can be grown having the pattern on a surface of the thin film, including on the top surface opposite the substrate. The nanoscale material can be graphene, graphene oxide, reduced graphene oxide, molybdenum disulfide, hexagonal boron nitride, tungsten diselenide, molybdenum trioxide, or clays such as montmorillonite or lapnotie. The porous substrate can be a porous organic or inorganic membrane, a silicon stencil membrane, or similar membrane having pore sizes on the order of microns.

Method for preparing microstructure arrays on the surface of thin film material

KAUST Repository

Wang, Peng

2017-02-09

Methods are provided for growing a thin film of a nanoscale material. Thin films of nanoscale materials are also provided. The films can be grown with microscale patterning. The method can include vacuum filtration of a solution containing the nanostructured material through a porous substrate. The porous substrate can have a pore size that is comparable to the size of the nanoscale material. By patterning the pores on the surface of the substrate, a film can be grown having the pattern on a surface of the thin film, including on the top surface opposite the substrate. The nanoscale material can be graphene, graphene oxide, reduced graphene oxide, molybdenum disulfide, hexagonal boron nitride, tungsten diselenide, molybdenum trioxide, or clays such as montmorillonite or lapnotie. The porous substrate can be a porous organic or inorganic membrane, a silicon stencil membrane, or similar membrane having pore sizes on the order of microns.

The wet corrosion of molybdenum thin film. Part I: Behavior at 25 C

International Nuclear Information System (INIS)

De Rosa, L.; Tomachuk, C.R.; Mitton, D.B.; Saiello, S.; Bellucci, F.; Springer, J.

2004-01-01

The corrosion and passivation behaviour of molybdenum thin films obtained by Physical Vapor Deposition (PVD) was investigated in aerated chloride and sulfate solutions at different pH values. Open circuit potential (ocp) measurements, polarisation experiments and electrochemical impedance spectroscopy (EIS) were employed. The experimental results suggest that the metal surface is covered by a passive film; however, corrosion still occurs. For the samples assessed during the current research, the acidic electrolytes tended to be less corrosive; however, a limited passive region was associated with the most basic sulfate or chloride solution. The effect of the pH was found to be more pronounced than the effect of the ion (chloride or sulfate). (Abstract Copyright [2004], Wiley Periodicals, Inc.)

A study on the alkali leaching of complex compound for molybdenum trioxide and ferric oxide

International Nuclear Information System (INIS)

Kim, C.G.; Whang, Y.K.

1981-01-01

This study is to determine the alkali-leaching meachanism by which complex compound by the reaction made between molybdenite (MoS 2 ) and ferric oxide (Fe 2 O 3 ) in the roasted are when molybdenum trioxide (MoO 3 ) is formed by the roasting reaction of molybdenite concentrate. The results obtained from this experiment are summarized as follows: The heating reaction analysis shows that the complex compound of iron molybdates (Fe 2 O 3 .3-4 MoO 3 ) is formed by the reaction of molybdenum trioxide and ferric oxide at temperatures of above 500 0 C. It is shown that at various reaction temperature below 400 0 C molybdenum trioxide is almost completely leached by caustic soda irrespective of the mole ratio of two chemical samples used for the experiment, whereas at temperature above 400 0 C the leaching rate of molybdenum trioxide decreases except that it varies from 70.77% at a temperature of 900 0 C at which the mole ratio is 1 to 1 to 84.08% at a temperature of 1000 0 C. The x-ray diffraction analysis has shown that the complex compound reacted at a temperature of 1000 0 C produces a complex compound with the crystal structure of iron molybdates, and the alkali-leached residues even with 19.0% of molybdenum trioxide, however, contain only α-Fe 2 O 3 , without showing iron molybdates. The crystalline compound of iron molybdates obtained as a result of heating reaction was leached by using caustic soda, while MoO 3 and Fe 2 O 3 in the leaching residue was found to contain other compounds unable to be leached by caustic soda. (author)

Investigation of hydrogen evolution activity for the nickel, nickel-molybdenum nickel-graphite composite and nickel-reduced graphene oxide composite coatings

International Nuclear Information System (INIS)

Jinlong, Lv; Tongxiang, Liang; Chen, Wang

2016-01-01

Graphical abstract: - Highlights: • Improved HER efficiency of Ni-Mo coatings was attributed to ‘cauliflower’ like microstructure. • RGO in nickel-RGO composite coating promoted refined grain and facilitated HER. • Synergistic effect between nickel and RGO facilitated HER due to large specific surface of RGO. - Abstract: The nickel, nickel-molybdenum alloy, nickel-graphite and nickel-reduced graphene oxide composite coatings were obtained by the electrodeposition technique from a nickel sulfate bath. Nanocrystalline molybdenum, graphite and reduced graphene oxide in nickel coatings promoted hydrogen evolution reaction in 0.5 M H_2SO_4 solution at room temperature. However, the nickel-reduced graphene oxide composite coating exhibited the highest electrocatalytic activity for the hydrogen evolution reaction in 0.5 M H_2SO_4 solution at room temperature. A large number of gaps between ‘cauliflower’ like grains could decrease effective area for hydrogen evolution reaction in slight amorphous nickel-molybdenum alloy. The synergistic effect between nickel and reduced graphene oxide promoted hydrogen evolution, moreover, refined grain in nickel-reduced graphene oxide composite coating and large specific surface of reduced graphene oxide also facilitated hydrogen evolution reaction.

Investigation of hydrogen evolution activity for the nickel, nickel-molybdenum nickel-graphite composite and nickel-reduced graphene oxide composite coatings

Energy Technology Data Exchange (ETDEWEB)

Jinlong, Lv, E-mail: ljlbuaa@126.com [Beijing Key Laboratory of Fine Ceramics, Institute of Nuclear and New Energy Technology, Tsinghua University, Zhongguancun Street, Haidian District, Beijing 100084 (China); State Key Lab of New Ceramic and Fine Processing, Tsinghua University, Beijing 100084 (China); Tongxiang, Liang; Chen, Wang [Beijing Key Laboratory of Fine Ceramics, Institute of Nuclear and New Energy Technology, Tsinghua University, Zhongguancun Street, Haidian District, Beijing 100084 (China); State Key Lab of New Ceramic and Fine Processing, Tsinghua University, Beijing 100084 (China)

2016-03-15

Graphical abstract: - Highlights: • Improved HER efficiency of Ni-Mo coatings was attributed to ‘cauliflower’ like microstructure. • RGO in nickel-RGO composite coating promoted refined grain and facilitated HER. • Synergistic effect between nickel and RGO facilitated HER due to large specific surface of RGO. - Abstract: The nickel, nickel-molybdenum alloy, nickel-graphite and nickel-reduced graphene oxide composite coatings were obtained by the electrodeposition technique from a nickel sulfate bath. Nanocrystalline molybdenum, graphite and reduced graphene oxide in nickel coatings promoted hydrogen evolution reaction in 0.5 M H{sub 2}SO{sub 4} solution at room temperature. However, the nickel-reduced graphene oxide composite coating exhibited the highest electrocatalytic activity for the hydrogen evolution reaction in 0.5 M H{sub 2}SO{sub 4} solution at room temperature. A large number of gaps between ‘cauliflower’ like grains could decrease effective area for hydrogen evolution reaction in slight amorphous nickel-molybdenum alloy. The synergistic effect between nickel and reduced graphene oxide promoted hydrogen evolution, moreover, refined grain in nickel-reduced graphene oxide composite coating and large specific surface of reduced graphene oxide also facilitated hydrogen evolution reaction.

The extended family of hexagonal molybdenum oxide

Energy Technology Data Exchange (ETDEWEB)

Hartl, Monika [Los Alamos National Laboratory; Daemen, Luke [Los Alamos National Laboratory; Lunk, J H [NON LANL; Hartl, H [NON LANL; Frisk, A T [NON LANL; Shendervich, I [NON LANL; Mauder, D [NON LANL; Feist, M [NON LANL; Eckelt, R [NON LANL

2009-01-01

Over the last 40 years, a large number of isostructural compounds in the system MoO{sub 3}-NH{sub 3}-H{sub 2}O have been published. The reported molecular formulae of 'hexagonal molybdenum oxide' (HEMO) varied from MoO{sub 3}, MoO{sub 3} {center_dot} 0.33NH{sub 3}, MoO{sub 3} {center_dot} nH{sub 2}O (0.09 {le} n {le} 0.69) to MoO{sub 3} {center_dot} mNH{sub 3} {center_dot} nH{sub 2}O (0.09 {le} m {le} 0.20; 0.18 {le} n {le} 0.60). Samples, prepared by the acidification route, were investigated using thermal analysis coupled on-line to a mass spectrometer for evolved gas analysis; X-ray powder diffraction; Fourier Transform Infrared, Raman and Magic-Angle-Spinning {sup 1}H-NMR spectroscopy; Incoherent Inelastic Neutron Scattering. The X-ray study of a selected monocrystal confirmed the presence of the well-known framework of edge-sharing MoO{sub 6} octahedra: Space group P6{sub 3}/m, a = 10.527(1), c =3.7245(7) {angstrom}, {gamma} = 120{sup o}. The structure of the synthesized samples can best be described by the structural formula (NH{sub 4})[Mo{sub x}{open_square}{sub 1/2+p/2}(O{sub 3x + 1/2-p/2})(OH){sub p}] {center_dot} yH{sub 2}O (x 5.9-7.1; p {approx} 0.1; y = 1.2-2.6), which is consistent with the existence of one vacancy for 12-15 molybdenum sites. The 'chimie douce' reaction of MoO{sub 3} {center_dot} 0.155NH{sub 3} {center_dot} 0.440H{sub 2}O with a 1:1 mixture of NO/NO{sub 2} at 100 C resulted in the synthesis of MoO{sub 3} {center_dot} 0.539H{sub 2}O. Tailored nano-sized molybdenum powders can be produced using HEMO as precursor.

Oxidation films morphology

International Nuclear Information System (INIS)

Paidassi, J.

1960-01-01

After studying the oxidation of several pure polyvalent metals (Fe, Cu, Mn, Ni, U) and of their oxides at high temperature and atmospheric pressure, the author suggests how to modify the usual representation of the oxide film (a piling of different oxide layers, homogeneous on a micrographic scale with a equi-axial crystallisation, free of mechanical tensions, with flat boundary surfaces) to have it nearer to reality. In this first part, the author exposes the study of the real micrographic structure of the oxidation film and gives examples of precipitation in the oxides during the cooling of the oxidised sample. (author) [fr

Study of molybdenum oxide by means of Perturbed Angular Correlations (PAC) and Mössbauer spectroscopy

CERN Multimedia

Among transition-metal oxides, the molybdenum oxide compounds are particularly attractive due to the structural (2D) anisotropy and to the ability of the molybdenum ion to change its oxidation state. These properties make it suitable for applications on, e.g., chemical sensors, solar cells, catalytic and optoelectronic devices. At ISOLDE we aim studying the incorporation of selected dopants by ion implantation, using the nuclear techniques of Perturbed Angular Correlations (PAC) and Mössbauer spectroscopy (MS). Both techniques make use of highly diluted radioactive probe nuclei, which interact – as atomic-sized tips – with the host atoms and defects. The objectives of this project are to study at the atomic scale the probe’s local environment, its electronic configuration and polarization, the probe’s lattice sites, point defects and its recombination dynamics. In the case of e-$\\gamma$ PAC, the electron mobility on the host can be further studied, e.g., as a function of temperature.

Investigation into electrochemical behavior of molybdenum VM-1 alloy at high current density

Energy Technology Data Exchange (ETDEWEB)

Tatarinova, O M; Amirkhanova, N A; Akhmadiev, A G

1975-01-01

The effect of the composition and concentration of electrolyte on the workability of the molybdenum VM-1 alloy has been studied and a number of anions has been determined relative to their activation capacity. The best workability of the alloy is achieved in a 15% NaOH solution and a composite electrolyte 15% NaNO/sub 3/+5%NaOH. It is shown that in polarization of the VM-1 alloy both in alkali- and salt solutions a film of oxides of different valence molybdenum is formed: Mo/sub 2/O/sub 3/, Mo/sub 4/O/sub 11/, Mo/sub 9/O/sub 26/, MoO/sub 3/, but molybdenum gets dissolved only in a hexavalent form, its content in a solution being in conformity with the polarizing current densities. Using a temperature-kinetic technique it has been found that the concentrational polarization is the limiting stage in the reaction of molybdenum and VM-1 alloy anodic dissolution in 15% NaNO/sub 3/ solution and in the composite electrolyte 15%NaNO/sub 3/+5%NaOH.

Determination of molybdenum (VI) by its catalytic effect on the oxidation of nile blue by hydrogen peroxide

International Nuclear Information System (INIS)

Ensafi, Ali A.; Sadeghie, Majid M.; Alaie-Yazdie, F.

1998-01-01

A spectrophotometric reaction rate method for the determination of molybdenum is described, based on its catalytic effect on the oxidation of nile blue by hydrogen peroxide. The decrease in absorbance of nile blue with time from 0.5 to 4 min at 590 nm is proportional to the concentration of Mo(VI) over the range 0.022-1000 μg/ml. The limit of detection of molybdenum(VI) is 0.008 μg/ml. The precision and the effect of more than forty ions are reported. The procedure has been successfully applied for the determination of molybdenum (VI) in plant materials and steel samples. (author)

Molybdenum silicide based materials and their properties

International Nuclear Information System (INIS)

Yao, Z.; Stiglich, J.; Sudarshan, T.S.

1999-01-01

Molybdenum disilicide (MoSi 2 ) is a promising candidate material for high temperature structural applications. It is a high melting point (2030 C) material with excellent oxidation resistance and a moderate density (6.24 g/cm 3 ). However, low toughness at low temperatures and high creep rates at elevated temperatures have hindered its commercialization in structural applications. Much effort has been invested in MoSi 2 composites as alternatives to pure molybdenum disilicide for oxidizing and aggressive environments. Molybdenum disilicide-based heating elements have been used extensively in high-temperature furnaces. The low electrical resistance of silicides in combination with high thermal stability, electron-migration resistance, and excellent diffusion-barrier characteristics is important for microelectronic applications. Projected applications of MoSi 2 -based materials include turbine airfoils, combustion chamber components in oxidizing environments, missile nozzles, molten metal lances, industrial gas burners, diesel engine glow plugs, and materials for glass processing. On this paper, synthesis, fabrication, and properties of the monolithic and composite molybdenum silicides are reviewed

Hydrogen in hydrogenated amorphous silicon thick film and its relation to the photoresponse of the film in contact with molybdenum

International Nuclear Information System (INIS)

Sridhar, N.; Chung, D.D.L.

1992-01-01

This paper reports that hydrogenated amorphous silicon films of thickness 0.5-7 μm on molybdenum substrates were deposited from silane by dc glow discharge and studied by mass spectrometric observation of the evolution of hydrogen upon heating and correlating this information with the photoresponse. The films were found to contain two types of hydrogen, namely weak bonded hydrogen, which evolved at 365 degrees C and was the minority, and strongly bonded hydrogen, which evolved at 460-670 degrees C and was the majority. The proportion of strongly bonded hydrogen increased with increasing film thickness and with increasing substrate temperature during deposition. The total amount of hydrogen increased when the substrate temperature was decreased from 350 to 275 degrees C. The strongly bonded hydrogen resided throughout the thickness of the film, whereas the weakly bonded hydrogen resided near the film surface. The evolution of the strongly bonded hydrogen was diffusion controlled, with an activation energy of 1.6 eV. The strongly bonded hydrogen enhanced the photoresponse, whereas the weakly bonded hydrogen degraded the photoresponse

Estimation of the effect of molybdenum on chemical and electrochemical stability of iron-based alloys

International Nuclear Information System (INIS)

Tyurin, A.G.

2003-01-01

The E-pH diagram for Mo-H 2 O system is made more precise. It is shown that a passivating film on molybdenum in weakly acid, neutral and alkali solutions may constitute MoO 2 only. In strongly acid solutions at anodic polarization the film should transform according to the following scheme: MoO 2 → Mo 4 O 11 → Mo 9 O 26 → MoO 3 . Sections of a Fe-Mo-O system phase diagram and a Fe-Mo-H 2 O system E-pH diagram at 25 deg C are plotted. MoO 2 is found to be a product of iron-molybdenum alloy oxidation in the air and in water. For the system of alloy Kh17N13M2-H 2 O the section of a E-pH diagram is plotted at 25 deg C [ru

Direct atomic-emission determination of tungsten in molybdenum oxide in dc arc

International Nuclear Information System (INIS)

Zolotareva, N.I.; Grazhulene, S.S.

2007-01-01

A method of direct atomic-emission determination of tungsten impurity in molybdenum trioxide of high purity in dc arc is presented. Chemically active additives of elementary sulfur and gallium oxide are used to optimize W evaporation rate and residence time in the arc plasma. The procedure is easy to use and provides the limit of W determination at a level of 2x10 -4 wt. % [ru

Rare Earth Oxide Thin Films

CERN Document Server

Fanciulli, Marco

2007-01-01

Thin rare earth (RE) oxide films are emerging materials for microelectronic, nanoelectronic, and spintronic applications. The state-of-the-art of thin film deposition techniques as well as the structural, physical, chemical, and electrical properties of thin RE oxide films and of their interface with semiconducting substrates are discussed. The aim is to identify proper methodologies for the development of RE oxides thin films and to evaluate their effectiveness as innovative materials in different applications.

Thin film metal-oxides

CERN Document Server

Ramanathan, Shriram

2009-01-01

Presents an account of the fundamental structure-property relations in oxide thin films. This title discusses the functional properties of thin film oxides in the context of applications in the electronics and renewable energy technologies.

Sputtered tin oxide and titanium oxide thin films as alternative transparent conductive oxides

Energy Technology Data Exchange (ETDEWEB)

Boltz, Janika

2011-12-12

Alternative transparent conductive oxides to tin doped indium oxide have been investigated. In this work, antimony doped tin oxide and niobium doped titanium oxide have been studied with the aim to prepare transparent and conductive films. Antimony doped tin oxide and niobium doped titanium oxide belong to different groups of oxides; tin oxide is a soft oxide, while titanium oxide is a hard oxide. Both oxides are isolating materials, in case the stoichiometry is SnO{sub 2} and TiO{sub 2}. In order to achieve transparent and conductive films free carriers have to be generated by oxygen vacancies, by metal ions at interstitial positions in the crystal lattice or by cation doping with Sb or Nb, respectively. Antimony doped tin oxide and niobium doped titanium oxide films have been prepared by reactive direct current magnetron sputtering (dc MS) from metallic targets. The process parameters and the doping concentration in the films have been varied. The films have been electrically, optically and structurally analysed in order to analyse the influence of the process parameters and the doping concentration on the film properties. Post-deposition treatments of the films have been performed in order to improve the film properties. For the deposition of transparent and conductive tin oxide, the dominant parameter during the deposition is the oxygen content in the sputtering gas. The Sb incorporation as doping atoms has a minor influence on the electrical, optical and structural properties. Within a narrow oxygen content in the sputtering gas highly transparent and conductive tin oxide films have been prepared. In this study, the lowest resistivity in the as deposited state is 2.9 m{omega} cm for undoped tin oxide without any postdeposition treatment. The minimum resistivity is related to a transition to crystalline films with the stoichiometry of SnO{sub 2}. At higher oxygen content the films turn out to have a higher resistivity due to an oxygen excess. After post

Weldability of powder-metallurgy molybdenum with low oxygen content

International Nuclear Information System (INIS)

Hiraoka, Yutaka; Okada, Masatoshi

1987-01-01

Relationships between the formation of weld pores and the chemical compositions in powder-metallurgy molybdenum were investigated. It is suggested that almost 100% of Ca and Mg form oxides. In contrast, Fe, Ni, Cr and Al, Si only partly form oxides. A powder-metallurgy molybdenum containing less than 84 at.ppm oxygen did not show any large weld pores. The reduction of the oxygen content was achieved by purifying the molybdenum powder. (orig.) [de

Influence of iron and beryllium additions on heat resistance of silicide coatings on TsMB-30 molybdenum alloy

International Nuclear Information System (INIS)

Zajtseva, A.L.; Fedorchuk, N.M.; Lazarev, Eh.M.; Korotkov, N.A.

1985-01-01

Alloying of titanium modified silicide coatings on TsMB-30 molybdenum alloy with iron or beryllium is stated to improve their protective properties. Coatings with low content of alloying elements have the best protective properties. Service life of coatings is determined by the formed oxide film and phase transformations taking place in the coating

Erosion behaviour of physically vapour-deposited and chemically vapour-deposited SiC films coated on molybdenum during oxygenated argon beam thinning

International Nuclear Information System (INIS)

Shikama, T.; Kitajima, M.; Fukutomi, M.; Okada, M.

1984-01-01

The erosion behaviour during bombardment with a 5 keV argon beam at room temperature was studied for silicon carbide (SiC) films of thickness of about 10 μm coated on molybdenum by physical vapour deposition (PVD) and chemical vapour deposition (CVD). The PVD SiC (plasma-assisted ion plating) exhibited a greater thinning rate than the CVD SiC film. Electron probe X-ray microanalysis revealed that the chemical composition of PVD SiC was changed to a composition enriched in silicon by the bombardment, and there was a notable change in its surface morphology. The CVD SiC retained its initial chemical composition with only a small change in its surface morphology. Auger electron spectroscopy indicated that silicon oxide was formed on the surface of PVD SiC by the bombardment. The greater thinning rate and easier change in chemical composition in PVD SiC could be attributed to its readier chemical reaction with oxygen due to its more non-uniform structure and weaker chemical bonding. Oxygen was present as one of the impurities in the argon beam. (Auth.)

Plastic flow and preferred orientation in molybdenum and zirconium films

International Nuclear Information System (INIS)

Window, B.

1989-01-01

X-ray diffraction measurements on samples of molybdenum and zirconium growth with ion assistance at low temperatures support the occurrence of plastic flow during growth, provided the level of bombardment is high enough. As the energy of the argon ions was increased, the lattice strain in the growth direction increased to a maximum before decreasing slowly. That this is a plastic flow transition is shown by the independence of the maximum strain on preparation conditions and by the changes in microstructure. In particular, the grain size in the growth direction decreased and the preferred orientation favored the usual wire drawing textures of these metals. For the zirconium films this involved a change in preferred orientation from a (00.2) to a (10.0) texture. A reduction in strain is observed at high bombardment levels

Method for palladium activating molybdenum metallized features on a ceramic substrate

International Nuclear Information System (INIS)

Kumar, A.H.; Schwartz, B.

1985-01-01

A molybdenum or tungsten metallurgical pattern is formed on or in a dielectric green sheet. Palladium, nickel, platinum or rhodium is coated on a layer of polyvinyl butyral which is carried on a polyester film. The metal layer of this assembly is laminated to a dielectric green sheet which carries the molybdenum or tungsten metallurgy. The polyester film is stripped off. The resulting assembly is sintered to a fired structure, whereby the polyvinyl butyral is volatilized off and the palladium, nickel, platinum or rhodium is alloyed with the molybdenum or tungsten metallurgy to provide a densified metallurgy whose surface is free of glass

Determination of molybdenum by the gravimetric plumbate method (with the molybdenum content from 50 % and above)

International Nuclear Information System (INIS)

Stepin, V.V.; Kurbatova, V.I.; Fedorova, N.D.

1980-01-01

A gravimetric method of molybdenum determination in ferromolybdenum (Mo content from 50% and higher) after its dissolving in HNO 3 is developed. The method is based on Mo deposition in acetic acid solution in the form of molybdenum oxide lead after separation of Fe and other interfering elements with sodium hydroxide [ru

Molybdenum oxide nanosheets prepared by an anodizing-exfoliation process and observation of photochromic properties

Energy Technology Data Exchange (ETDEWEB)

Ranjba, M., E-mail: ranjbar@cc.iut.ac.ir; Delalat, F.; Salamati, H.

2017-02-28

Highlights: • Blue molybdenum oxide nanosheets are prepared by a facile anodizing method. • PdCl{sub 2} solution is able to decolorize the nanosheets from blue to colorless. • The colorless colloids show a strong photochromic effect under UV laser irradiation. - Abstract: Anodizing-exfoliation of molybdenum foil was performed in 0.02 M HCl electrolyte at 30 V. In this process, the electrolyte rapidly turned into a blue colloidal solution of molybdenum oxide nanosheets with fragmented edges observed on transmission electron microscope (TEM). X-ray Diffraction (XRD) pattern of particles was free of peak while annealing at a temperature range of 100–500 °C led to formation of monoclinic (for T < 300 °C) and orthorhombic (for T > 300 °C) phases of MoO{sub 3}. Moreover, addition of PdCl{sub 2} (0.2 g/l) salt solution caused a spontaneous bleaching of the initial blue colloid. Annealing of powders extracted from these bleached solutions with different PdCl{sub 2} concentrations at 500 °C led to a preferential growth of (0k0) orientation. X-ray photoelectron spectroscopy (XPS) revealed that the blue nanosheets solution contains mainly Mo{sup 5+} with slightly Mo{sup 6+} oxidation states and each of annealing or salt bleaching procedures can entirely convert Mo{sup 5+} to Mo{sup 6+}. When the bleached solutions was exposed to KrF laser beam (λ = 248 nm) a strong photochromic coloration with a deep blue color was occurred. Regardless of Pd:Mo ratio, the primary and laser irradiated solutions showed analogues optical absorption bands in the 1–3 nm photon energy range while the photochromic process led to a broader absorption band.

Ultra-fast Movies Resolve Ultra-short Pulse Laser Ablation and Bump Formation on Thin Molybdenum Films

Science.gov (United States)

Domke, Matthias; Rapp, Stephan; Huber, Heinz

For the monolithic serial interconnection of CIS thin film solar cells, 470 nm molybdenum films on glass substrates must be separated galvanically. The single pulse ablation with a 660 fs laser at a wavelength of 1053 nm is investigated in a fluence regime from 0.5 to 5.0 J/cm2. At fluences above 2.0 J/cm2 bump and jet formation can be observed that could be used for creating microstructures. For the investigation of the underlying mechanisms of the laser ablation process itself as well as of the bump or jet formation, pump probe microscopy is utilized to resolve the transient ablation behavior.

Cermet sintering on the oase of molybdenum, nickel, aluminium oxide in dry and wet hydrogen medium

International Nuclear Information System (INIS)

Fedotov, A.V.; Lutskaya, E.Eh.

1985-01-01

Cermet sintering on the base of molybdenum, nickel and aluminium oxide in dry and wer hydrogen medium is studied. It is stated that presence of water vapours permits to decrease sintering temperature of molybdenum containing cermets and to prepare dense nickeliferous cermets. Cermet density can he rather high at final stages of sintering that is probably conditioned by decrease of growth rate of corundum crystals. Pressing pressure activates cermet siptering at intermediate stages and it is low effective at finite stages of condensation. Constancy of relative reduction of void volume is preserved only at final stages of sintering

Water-soluble thin film transistors and circuits based on amorphous indium-gallium-zinc oxide.

Science.gov (United States)

Jin, Sung Hun; Kang, Seung-Kyun; Cho, In-Tak; Han, Sang Youn; Chung, Ha Uk; Lee, Dong Joon; Shin, Jongmin; Baek, Geun Woo; Kim, Tae-il; Lee, Jong-Ho; Rogers, John A

2015-04-22

This paper presents device designs, circuit demonstrations, and dissolution kinetics for amorphous indium-gallium-zinc oxide (a-IGZO) thin film transistors (TFTs) comprised completely of water-soluble materials, including SiNx, SiOx, molybdenum, and poly(vinyl alcohol) (PVA). Collections of these types of physically transient a-IGZO TFTs and 5-stage ring oscillators (ROs), constructed with them, show field effect mobilities (∼10 cm2/Vs), on/off ratios (∼2×10(6)), subthreshold slopes (∼220 mV/dec), Ohmic contact properties, and oscillation frequency of 5.67 kHz at supply voltages of 19 V, all comparable to otherwise similar devices constructed in conventional ways with standard, nontransient materials. Studies of dissolution kinetics for a-IGZO films in deionized water, bovine serum, and phosphate buffer saline solution provide data of relevance for the potential use of these materials and this technology in temporary biomedical implants.

Ultra-thin solution-based coating of molybdenum oxide on multiwall carbon nanotubes for high-performance supercapacitor electrodes

KAUST Repository

Shakir, Imran

2014-02-01

Uniform and conformal coating of ultrathin molybdenum oxide (MoO 3) thin film onto conducting MWCNTs was successfully synthesized through a facile, nontoxic and generally applicable precipitation method, followed by a simple heat treatment. The ultrathin MoO3 coating enables a fast and reversible redox reaction which improves the specific capacitance by utilizing the maximum number of active sites for the redox reaction, while the high porosity of the MWCNTs facilitates ion migration in the electrolyte and shorten the ion diffusion path. The ultrathin MoO3 coated MWCNTs electrodes show a very high specific capacitance of 1145 Fg -1 in 2 M Na2SO4 aqueous solution when 5 nm thick MoO3 was considered alone despite the low weight percentage of the MoO3 (16wt%). Furthermore, the ultrathin MoO3 coated MWCNTs supercapacitor electrodes exhibited excellent cycling performance of > 97% capacitance retention over 1000 cycles. © 2013 Elsevier Ltd.

A study of emission property and microstructure of rare earth oxide-molybdenum cermet cathode materials made by spark plasma sintering

International Nuclear Information System (INIS)

Wang Jinshu; Li Hongyi; Yang Sa; Cui Ying; Zhou Meiling

2004-01-01

A fast sintering method, spark plasma sintering (SPS) was used for the synthesis of rare earth oxide-molybdenum cathode material. The secondary emission property, microstructure, and phase constitution of materials have been studied in this paper. The experimental results show that the maximum secondary emission coefficient of this material can be high to 3.84, much higher than that of rare earth oxide-molybdenum cathode made by traditional sintering method. The grain size is less than 1 μm and rare earth distributed evenly in the material. After the material was activated at 1600 deg. C, a 4 μm layer of rare earth oxide which leads to the high secondary emission coefficient of the material, is formed on the surface of the cathode

Photoemission Spectroscopy Characterization of Attempts to Deposit MoO2 Thin Film

Directory of Open Access Journals (Sweden)

Irfan

2011-01-01

Full Text Available Attempts to deposit molybdenum dioxide (MoO2 thin films have been described. Electronic structure of films, deposited by thermal evaporation of MoO2 powder, had been investigated with ultraviolet photoemission and X-ray photoemission spectroscopy (UPS and XPS. The thermally evaporated films were found to be similar to the thermally evaporated MoO3 films at the early deposition stage. XPS analysis of MoO2 powder reveals presence of +5 and +6 oxidation states in Mo 3d core level along with +4 state. The residue of MoO2 powder indicates substantial reduction in higher oxidation states while keeping +4 oxidation state almost intact. Interface formation between chloroaluminum phthalocyanine (AlPc-Cl and the thermally evaporated film was also investigated.

Stabilized chromium oxide film

Science.gov (United States)

Garwin, Edward L.; Nyaiesh, Ali R.

1988-01-01

Stabilized air-oxidized chromium films deposited on high-power klystron ceramic windows and sleeves having a thickness between 20 and 150.ANG. are useful in lowering secondary electron emission yield and in avoiding multipactoring and window failure due to overheating. The ceramic substrate for the film is chosen from alumina, sapphire or beryllium oxide.

Flame retardant synergism between molybdenum and halogen-containing compounds in unsaturated polyesters. [Smoke suppression

Energy Technology Data Exchange (ETDEWEB)

Skinner, G.A.; Parker, L.E.; Marshall, P.J.

1978-01-01

Oxygen index results for a series of unsaturated polyesters, containing molybdenum oxide and various halogenated compounds, have provided definite evidence for some form of flame retardant synergistic effect between molybdenum and halogen. With the halogenated compounds used, the magnitude of the effect was greater in the presence of bromine but was dependent on the type of compound. When dibromoneopentyl glycol was used as the bromine source, the synergistic effect exhibited by molybdenum oxide was comparable to that shown by antimony oxide. Since molybdenum oxide also acts as a smoke suppressant, it could offer a useful alternative to antimony oxide particularly in the light of probable changes in standards and regulatory control regarding smoke emission. 4 figures, 2 tables.

Recent situation and future of molybdenum mineral resources; Molybdenum shigen no genjo to shorai

Energy Technology Data Exchange (ETDEWEB)

Ono, K.; Nishiyama, T. [Kyoto University, Kyoto (Japan)

1997-05-05

Molybdenum is produced mainly from molybdenite, and the majority of this ore is exploited from the porphyry deposit. The reserve is estimated at 5.5-million ton. A total of 118-thousand ton was produced across the world in 1995, in the U.S., China, Chile, and Canada, the countries named in the order of quantities they exploited. Molybdenite is first refined by flotation for the production of a sulphide. It is subjected to oxidizing roasting for conversion into crude molybdenum trioxide, which is next subjected to extraction in warmed-up aqueous ammonia and then to evaporation for the crystallization of ammonium paramolybdate. The crystals are baked for conversion into molybdenum trioxide of the ordinary purity, to be further processed into ferromolybdenum, molybdenum compounds, molybdenum powder, etc. In view of the magnitude of demand, the metal is used mostly for the manufacture of special steels and special alloys. The demand for this metal, though small in size, involves important articles, such as line materials for semiconductors in the power industry, catalysts in the chemical industry, and lubricants. Japan`s stockpile includes molybdenum, but the U.S. has been stockpiling none since 1977. 9 refs., 4 figs., 1 tab.

Molybdenum oxide nanowires based supercapacitors with enhanced capacitance and energy density in ethylammonium nitrate electrolyte

Energy Technology Data Exchange (ETDEWEB)

Sarfraz, Mansoor; Aboud, Mohamed F.A.; Shakir, Imran, E-mail: shakir@skku.edu

2015-11-25

Orthorhombic molybdenum trioxide (α-MoO{sub 3}) nanowires as an electrode for electrochemical supercapacitors in ethylammonium nitrate (EAN) electrolyte exhibits a high specific capacitance of 288 Fg{sup −1}, which is 8 times higher than the specific capacitance obtained from MoO{sub 3} nanowires in water based electrolyte. MoO{sub 3} nanowires in EAN electrolyte exhibit energy density of 46.32 Wh kg{sup −1} at a power density of 20.3 kW kg{sup −1} with outstanding cycling stability with specific capacitance retention of 96% over 3000 cycles. We believe that the superior performance of the MoO{sub 3} nanowires in EAN based electrolyte is primarily due to its relatively low viscosity (0.28 P at 25 °C), high electrical conductivity (20 mS cm{sup −1} at 25 °C) and large working voltage window. The results clearly demonstrate that EAN as electrolyte is one of the most promising electrolyte for high performance large scale energy storage devices. - Highlights: • Synthesis of single crystalline molybdenum oxide nanowires. • Ethylammonium Nitrate as an electrolyte for high performance large scale psuedocapacitor based energy storage devices. • Molybdenum oxide nanowires based electrodes shows 8 fold enhancement in Ethylammonium Nitrate electrolyte as compared to water based electrolytes. • The devices in Ethylammonium Nitrate exhibit excellent stability, retaining 96% of its initial capacity after 3000 cycles.

Reaction products and corrosion of molybdenum electrode in glass melt containing antimony oxides and sodium sulfate

Czech Academy of Sciences Publication Activity Database

Matěj, J.; Langrová, Anna

2012-01-01

Roč. 56, č. 3 (2012), s. 280-285 ISSN 0862-5468 Institutional support: RVO:67985831 Keywords : antimony oxides * corrosion * glass melt * Molybdenum electrode * sulfate Subject RIV: DD - Geochemistry Impact factor: 0.418, year: 2012 http://www.ceramics-silikaty.cz/2012/pdf/2012_03_280.pdf

Molybdenum: the element and aqueous solution chemistry

International Nuclear Information System (INIS)

Sykes, A.G.

1987-01-01

This chapter on the chemistry of the coordination compounds of molybdenum concentrates on the element itself, its recovery from ores and its use in the manufacture of steels. Most of the chapter is devoted to the aqueous solution chemistry of molybdenum in oxidation states II, III and IV. (UK)

Behavior of molybdenum in pyrochemical reprocessing: A spectroscopic study of the chlorination of molybdenum and its oxides in chloride melts

International Nuclear Information System (INIS)

Volkovicha, Vladimir A.; Griffiths, Trevor R.; Thied, Robert C.; Lewin, Bob

2003-01-01

The high temperature reactions of molybdenum and its oxides with chlorine and hydrogen chloride in molten alkali metal chlorides were investigated between 400 and 700 deg. C. The melts studied were LiCl-KCl, NaCl-CsCl and NaCl-KCl and the reactions were followed by in situ electronic absorption spectroscopy measurements. In these melts Mo reacts with Cl 2 and initially produces MoCl 6 2- and then a mixture of Mo(III) and Mo(V) chlorocomplexes, the final proportion depending on the reaction conditions. The Mo(V) content can be removed as MoCl 5 from the melt under vacuum or be reduced to Mo(III) by Mo metal. The reaction of Mo when HCl gas is bubbled into alkali chloride melts yields only MoCl 6 3- . MoO 2 reacts in these melts with chlorine to form soluble MoOCl 5 2- and volatile MoO 2 Cl 2 . MoO 3 is soluble in chloride melts and then decomposes into the oxychloride MoO 2 Cl 2 , which sublimes or can be sparged from the melt, and molybdate. Pyrochemical reprocessing can thus be employed for molybdenum since, after various intermediates, the end-products are chloride melts containing chloro and oxychloro anions of molybdenum plus molybdate, and volatile chlorides and oxychlorides that can be readily separated off. The reactions were fastest in the NaCl-KCl melt. The X-ray diffraction pattern of MoO 2 Cl 2 is reported for the first time

The behaviour of molybdenum dialkyldithiocarbamate friction modifier additives

International Nuclear Information System (INIS)

Graham, Jocelyn Claire Herries

2001-01-01

In recent years there has been growing concern to produce energy-efficient lubricated components and modem engine oil specifications require lubricants to demonstrate fuel efficiency in standardised engine tests. One important method of producing low friction and thus fuel-efficient lubricants is to use oil-soluble, molybdenum-containing, friction modifier additives. In optimal conditions these additives are able to produce very low friction coefficients, in the range 0.045 to 0.075 in boundary lubrication conditions. Very little is known about the chemical and physical mechanisms by which oil soluble molybdenum additives form low friction films in tribological contacts. Information about their activity could lead to optimal use of these additives in lubricants and, therefore, more efficient engine running. The work outlined in this thesis investigated the behaviour of oil-soluble molybdenum additives and showed that these additives were able to effectively reduce friction in the absence of other additives such as ZnDTP. Their activity was shown to be highly concentration and temperature dependent and was also found to be sensitive to the roughness of the contacting surfaces. Raman spectroscopy was used to analyse the chemical nature of molybdenum-containing reaction films and found that friction reduction indubitably arises from the local formation of platelets (diameter 30-50 nm) of MoS 2 . The formation of MoS 2 -rich films was found to occur only during direct asperity-asperity rubbing of the contacting surfaces (this type of contact being especially prevalent in pure sliding contacts). At elevated temperatures and in the presence of oxidising gases the consumption of MoDTC was monitored. MoDTC concentration dropped until the total value fell below a critical level to reduce friction. The study showed that decay rate of molybdenum-containing species was reduced by the addition of peroxide-decomposing antioxidants. (author)

Graphene oxide – molybdenum disulfide hybrid membranes for hydrogen separation

KAUST Repository

Ostwal, Mayur; Shinde, Digambar B.; Wang, Xinbo; Gadwal, Ikhlas; Lai, Zhiping

2017-01-01

Graphene oxide – molybdenum disulfide hybrid membranes were prepared using vacuum filtration technique. The thickness and the MoS2 content in the membranes were varied and their H2 permeance and H2/CO2 selectivity are reported. A 60nm hybrid membrane containing ~75% by weight of MoS2 exhibited the highest H2 permeance of 804×10−9mol/m2·s·Pa with corresponding H2/CO2 selectivity of 26.7; while a 150nm hybrid membrane with ~29% MoS2 showed the highest H2/CO2 selectivity of 44.2 with corresponding H2 permeance of 287×10−9mol/m2·s·Pa. The hybrid membranes exhibited much higher H2 permeance compared to graphene oxide membranes and higher selectivity compared to MoS2 membranes, which fully demonstrated the synergistic effect of both nanomaterials. The membranes also displayed excellent operational long-term stability.

Graphene oxide – molybdenum disulfide hybrid membranes for hydrogen separation

KAUST Repository

Ostwal, Mayur

2017-12-24

Graphene oxide – molybdenum disulfide hybrid membranes were prepared using vacuum filtration technique. The thickness and the MoS2 content in the membranes were varied and their H2 permeance and H2/CO2 selectivity are reported. A 60nm hybrid membrane containing ~75% by weight of MoS2 exhibited the highest H2 permeance of 804×10−9mol/m2·s·Pa with corresponding H2/CO2 selectivity of 26.7; while a 150nm hybrid membrane with ~29% MoS2 showed the highest H2/CO2 selectivity of 44.2 with corresponding H2 permeance of 287×10−9mol/m2·s·Pa. The hybrid membranes exhibited much higher H2 permeance compared to graphene oxide membranes and higher selectivity compared to MoS2 membranes, which fully demonstrated the synergistic effect of both nanomaterials. The membranes also displayed excellent operational long-term stability.

Method of molybdenum kinetic determination

International Nuclear Information System (INIS)

Krejngol'd, S.U.; Dzotsenidze, N.E.; Ruseishviyai, T.G.; Nelen', I.M.

1980-01-01

The method molybdenum kinetic determination according to oxidation of pyrogallol with bromate in the medium of 0.05-0.15 M perchloric or sulphuric acids is presented. 1 mg of Ni, Co, Mn, Mg, Zn, Cr(3); 100 μg of Ca, Al, Cu, 10 μg of Cr(4), W; 10 μg of Fe in the presence of 22x10 - 4 M solution of EDTA, as well as 10 - 4 M solutions of chlorides and fluorides, 10 - 5 M solutions of bromides do not interfere with molybdenum determination using the given method. The method is rather simple, it takes 30 min to carry out the analysis. Determination limit of molybdenum constitutes 0.01 μg/ml

Graphite oxide and molybdenum disulfide composite for hydrogen evolution reaction

Science.gov (United States)

Niyitanga, Theophile; Jeong, Hae Kyung

2017-10-01

Graphite oxide and molybdenum disulfide (GO-MoS2) composite is prepared through a wet process by using hydrolysis of ammonium tetrathiomolybdate, and it exhibits excellent catalytic activity of the hydrogen evolution reaction (HER) with a low overpotential of -0.47 V, which is almost two and three times lower than those of precursor MoS2 and GO. The high performance of HER of the composite attributes to the reduced GO supporting MoS2, providing a conducting network for fast electron transport from MoS2 to electrodes. The composite also shows high stability after 500 cycles, demonstrating a synergistic effect of MoS2 and GO for efficient HER.

Influence of Mo/MoSe{sub 2} microstructure on the damp heat stability of the Cu(In,Ga)Se{sub 2} back contact molybdenum

Energy Technology Data Exchange (ETDEWEB)

Theelen, Mirjam, E-mail: mirjam.theelen@tno.nl [TNO Solliance, Thin Film Technology, High Tech Campus 21, 5656 AE Eindhoven (Netherlands); Delft University of Technology, Photovoltaic Materials and Devices, Mekelweg 4, 2628 CD Delft (Netherlands); Harel, Sylvie [Institut des Matériaux Jean Rouxel (IMN)-UMR 6502, Université de Nantes, CNRS, 2 rue de la Houssinière, BP 32229, 44322 Nantes Cedex 3 (France); Verschuren, Melvin [TNO Solliance, Thin Film Technology, High Tech Campus 21, 5656 AE Eindhoven (Netherlands); Tomassini, Mathieu [Institut des Matériaux Jean Rouxel (IMN)-UMR 6502, Université de Nantes, CNRS, 2 rue de la Houssinière, BP 32229, 44322 Nantes Cedex 3 (France); Hovestad, Arjan [TNO Solliance, Thin Film Technology, High Tech Campus 21, 5656 AE Eindhoven (Netherlands); Barreau, Nicolas [Institut des Matériaux Jean Rouxel (IMN)-UMR 6502, Université de Nantes, CNRS, 2 rue de la Houssinière, BP 32229, 44322 Nantes Cedex 3 (France); Berkum, Jurgen van [Philips Innovation Services, High Tech Campus 11, 5656 AE Eindhoven (Netherlands); Vroon, Zeger [TNO Solliance, Thin Film Technology, High Tech Campus 21, 5656 AE Eindhoven (Netherlands); Zeman, Miro [Delft University of Technology, Photovoltaic Materials and Devices, Mekelweg 4, 2628 CD Delft (Netherlands)

2016-08-01

The degradation behavior of Mo/MoSe{sub 2} layers have been investigated using damp heat exposure. The two studied molybdenum based films with different densities and microstructures were obtained by lifting off Cu(In,Ga)Se{sub 2} layers from a bilayer molybdenum stack on soda lime glass. Hereby, a glass/Mo/MoSe{sub 2} was obtained, which resembles the back contact as present in Cu(In,Ga)Se{sub 2} solar cells. The samples were degraded for 150 h under standard damp heat conditions and analyzed before, during and after degradation. It was observed that the degradation resulted in the formation of needles and molybdenum oxide layers near the glass/Mo and the Mo/Cu(In,Ga)Se{sub 2} interfaces. X-ray Photoelectron Spectroscopy measurements have shown that the sodium was also present at the surface of the degraded material and it is proposed that the degraded material consists mostly of MoO{sub 3} with intercalated Na{sup +}. This element has likely migrated from the soda lime glass. This intercalation process could have led to the formation of Na{sub x}MoO{sub 3} ‘molybdenum bronze’ following this redox reaction: xNa{sup +} + MoO{sub 3} + xe{sup −} ↔ Na{sub x}MoO{sub 3} It is proposed that the formed oxide layer contains Na{sub x}MoO{sub 3} with different Na{sup +} contents and different grades of conductivity. This intercalation process can also explain the high mobility of Na{sup +} via the grain boundaries in molybdenum. It was also observed that the molybdenum film with a top layer deposited at a high pressure is more susceptible for damp heat degradation. - Highlights: • SLG/high pressure Mo/low pressure Mo/MoSe{sub 2} stacks were exposed to damp heat. • Molybdenum deposited at low pressure retained the best reflectivity and conductivity. • Damp heat exposure leads to a Na{sub x}MoO{sub 3}/Mo multilayer structure. • The Na{sub x}MoO{sub 3} probably consists of Na{sup +} intercalated in a (reduced) MoO{sub 3} matrix. • Intercalation can explain the

Spectrographic analysis of uranium-molybdenum alloys

International Nuclear Information System (INIS)

Roca, M.

1967-01-01

A spectrographic method of analysis has been developed for uranium-molybdenum alloys containing up to 10 % Mo. The carrier distillation technique, with gallium oxide and graphite as carriers, is used for the semiquantitative determination of Al, Cr, Fe, Ni and Si, involving the conversion of the samples into oxides. As a consequence of the study of the influence of the molybdenum on the line intensities, it is useful to prepare only one set of standards with 0,6 % MoO 3 . Total burning excitation is used for calcium, employing two sets of standards with 0,6 and 7.5 MoO 3 . (Author) 5 refs

Tungsten oxide proton conducting films for low-voltage transparent oxide-based thin-film transistors

International Nuclear Information System (INIS)

Zhang, Hongliang; Wan, Qing; Wan, Changjin; Wu, Guodong; Zhu, Liqiang

2013-01-01

Tungsten oxide (WO x ) electrolyte films deposited by reactive magnetron sputtering showed a high room temperature proton conductivity of 1.38 × 10 −4 S/cm with a relative humidity of 60%. Low-voltage transparent W-doped indium-zinc-oxide thin-film transistors gated by WO x -based electrolytes were self-assembled on glass substrates by one mask diffraction method. Enhancement mode operation with a large current on/off ratio of 4.7 × 10 6 , a low subthreshold swing of 108 mV/decade, and a high field-effect mobility 42.6 cm 2 /V s was realized. Our results demonstrated that WO x -based proton conducting films were promising gate dielectric candidates for portable low-voltage oxide-based devices.

The Effect of Sputtering Parameters on the Film Properties of Molybdenum Back Contact for CIGS Solar Cells

Directory of Open Access Journals (Sweden)

Peng-cheng Huang

2013-01-01

Full Text Available Molybdenum (Mo thin films are widely used as a back contact for CIGS-based solar cells. This paper determines the optimal settings for the sputtering parameters for an Mo thin film prepared on soda lime glass substrates, using direct current (dc magnetron sputtering, with a metal Mo target, in an argon gas environment. A Taguchi method with an L9 orthogonal array, the signal-to-noise ratio, and an analysis of variances is used to determine the performance characteristics of the coating operation. The main sputtering parameters, such as working pressure (mTorr, dc power (W, and substrate temperature (°C, are optimized with respect to the structural features, surface morphology, and electrical properties of the Mo films. An adhesive tape test is performed on each film to determine the adhesion strength of the films. The experimental results show that the working pressure has the dominant effect on electrical resistivity and reflectance. The intensity of the main peak (110 for the Mo film increases and the full width at half maximum decreases gradually as the sputtering power is increased. Additionally, the application of an Mo bilayer demonstrates good adherence and low resistivity.

Toward Annealing-Stable Molybdenum-Oxide-Based Hole-Selective Contacts For Silicon Photovoltaics

KAUST Repository

Essig, Stephanie

2018-02-21

Molybdenum oxide (MoOX) combines a high work function with broadband optical transparency. Sandwiched between a hydrogenated intrinsic amorphous silicon passivation layer and a transparent conductive oxide, this material allows a highly efficient hole-selective front contact stack for crystalline silicon solar cells. However, hole extraction from the Si wafer and transport through this stack degrades upon annealing at 190 °C, which is needed to cure the screen-printed Ag metallization applied to typical Si solar cells. Here, we show that effusion of hydrogen from the adjacent layers is a likely cause for this degradation, highlighting the need for hydrogen-lean passivation layers when using such metal-oxide-based carrier-selective contacts. Pre-MoOX-deposition annealing of the passivating a-Si:H layer is shown to be a straightforward approach to manufacturing MoOX-based devices with high fill factors using screen-printed metallization cured at 190 °C.

Experiment on bio-leaching of associated molybdenum and uranium ore

International Nuclear Information System (INIS)

Zheng Ying; Fan Baotuan; Liu Jian; Meng Yunsheng; Liu Chao

2007-01-01

Column leaching experiment results on associated molybdenum uranium ore by bacteria (T. f) are introduced. The ore are leached for 210 days using bacteria domesticated to tolerate molybdenum, the leaching of uranium is of 98% and leaching of molybdenum is of 41%. Sulphuric acid produced by bio-oxidation of sulfides in ore can meet the demand of ore leaching. (authors)

Molybdenum plasma spray powder, process for producing said powder, and coating made therefrom

International Nuclear Information System (INIS)

Lafferty, W.D.; Cheney, R.F.; Pierce, R.H.

1979-01-01

Plasma spray powders of molybdenum particles containing 0.5 to 15 weight percent oxygen and obtained by reacting molybdenum particles with oxygen or oxides in a plasma, form plasma spray coatings exhibiting hardness comparable to flame sprayed coatings formed from molybdenum wire and plasma coatings of molybdenum powders. Such oxygen rich molybdenum powders may be used to form wear resistant coatings, such as for piston rings. (author)

Large-Batch Reduction of Molybdenum Trioxide

Energy Technology Data Exchange (ETDEWEB)

Kiggans, Jr, James O. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Lowden, Richard Andrew [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Menchhofer, Paul A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Nunn, Stephen D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bryan, Chris [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2015-12-01

Unconverted, isotopically-enriched molybdenum metal must be recovered from the spent radiopharmaceutical solution used in NorthStar’s Technetium-99m generator and reused. The recycle process begins by recovering the metal from the aqueous potassium molybdate (K₂MoO₄) solutions as molybdenum trioxide (MoO₃) employing a process developed at Argonne National Laboratory. The MoO₃ powder is subsequently reduced to molybdenum metal powder which can be blended with new powder and further processed into a flowable form to be used to produce target disks for irradiation. The molybdenum oxide reduction process has been examined and scaled to produce kilogram quantities of metal powder suitable for processing into a useable form employing spray drying or similar technique and ultimately used for target fabrication.

The active component of vanadium-molybdenum catalysts for the oxidation of acrolein to acrylic acid

International Nuclear Information System (INIS)

Andrushkevich, T.V.; Kuznetsova, T.G.

1986-01-01

The catalytic properties of the vanadium-molybdenum oxide system were investigated in the oxidation of acrolein to acrylic acid. The active component of the catalyst is the compound VMo 3 O 11 , the maximum amount of which is observed at a content of 7-15 mole% V 2 O 4 . The compound VMo 3 O 11 is formed in the thermodecomposition of silicomolybdovanadium heteropoly acids or isopoly compounds, reduced with respect to vanadium, and contains V 4+ and Mo 6+ . The optimum treatment for the formation of this compound is treatment in the reaction mixture at 400 degrees C

UV photodissociation spectroscopy of oxidized undecylenic acid films.

Science.gov (United States)

Gomez, Anthony L; Park, Jiho; Walser, Maggie L; Lin, Ao; Nizkorodov, Sergey A

2006-03-16

Oxidation of thin multilayered films of undecylenic (10-undecenoic) acid by gaseous ozone was investigated using a combination of spectroscopic and mass spectrometric techniques. The UV absorption spectrum of the oxidized undecylenic acid film is significantly red-shifted compared to that of the initial film. Photolysis of the oxidized film in the tropospheric actinic region (lambda > 295 nm) readily produces formaldehyde and formic acid as gas-phase products. Photodissociation action spectra of the oxidized film suggest that organic peroxides are responsible for the observed photochemical activity. The presence of peroxides is confirmed by mass-spectrometric analysis of the oxidized sample and an iodometric test. Significant polymerization resulting from secondary reactions of Criegee radicals during ozonolysis of the film is observed. The data strongly imply the importance of photochemistry in aging of atmospheric organic aerosol particles.

Thin film removal mechanisms in ns-laser processing of photovoltaic materials

International Nuclear Information System (INIS)

Bovatsek, J.; Tamhankar, A.; Patel, R.S.; Bulgakova, N.M.; Bonse, J.

2010-01-01

The removal of thin films widely used in photovoltaics (amorphous silicon, tin oxide, zinc oxide, aluminum, and molybdenum) is studied experimentally using multi-kHz Q-switched solid-state lasers at 532 nm and 1064 nm wavelengths. The processing ('scribing') is performed through the film-supporting glass plate at scribing speeds of the order of m/s. The dependence of the film removal threshold on the laser pulse duration (8 ns to 40 ns) is investigated and the results are complemented by a multi-layer thermal model used for numerical simulations of the laser-induced spatio-temporal temperature field within the samples. Possible film removal mechanisms are discussed upon consideration of optical, geometrical, thermal and mechanical properties of the layers.

Laser patterning of superconducting oxide films

International Nuclear Information System (INIS)

Gupta, A.; Hussey, B.W.; Koren, G.; Cooper, E.I.; Jagannathan, R.

1988-01-01

The focused output of an argon ion laser (514.5 nm) has been used for wiring superconducting lines of Y/sub 1/Ba/sub 2/CU/sub 3/O/sub 7-δ/ using films prepared from nitrate and trifluoroacetate solution precursors. A stoichiometric solution of the precursors is sprayed or spun on to the substrate to form a film. The film is patterned by irradiating in selected areas to convert the irradiated layers to an intermediate oxide or fluoride state, the nonirradiated areas being unchanged. The nonirradiated areas are then dissolved away, leaving a pattern of the oxide or fluoride material. This patterned layer is converted to the superconducting 1-2-3 oxide in a subsequent annealing step. Maskless patterning of superconducting films has also been demonstrated by laser-assisted etching of the films in aqueous KOH solution. Although superconductivity is destroyed when the films are placed in solution, it can be restored after a brief anneal in oxygen

High stability mechanisms of quinary indium gallium zinc aluminum oxide multicomponent oxide films and thin film transistors

International Nuclear Information System (INIS)

Lee, Ching-Ting; Lin, Yung-Hao; Lin, Jhong-Ham

2015-01-01

Quinary indium gallium zinc aluminum oxide (IGZAO) multicomponent oxide films were deposited using indium gallium zinc oxide (IGZO) target and Al target by radio frequency magnetron cosputtering system. An extra carrier transport pathway could be provided by the 3 s orbitals of Al cations to improve the electrical properties of the IGZO films, and the oxygen instability could be stabilized by the strong Al-O bonds in the IGZAO films. The electron concentration change and the electron mobility change of the IGZAO films for aging time of 10 days under an air environment at 40 °C and 75% humidity were 20.1% and 2.4%, respectively. The experimental results verified the performance stability of the IGZAO films. Compared with the thin film transistors (TFTs) using conventional IGZO channel layer, in conducting the stability of TFTs with IGZAO channel layer, the transconductance g m change, threshold voltage V T change, and the subthreshold swing S value change under the same aging condition were improved to 7.9%, 10.5%, and 14.8%, respectively. Furthermore, the stable performances of the IGZAO TFTs were also verified by the positive gate bias stress. In this research, the quinary IGZAO multicomponent oxide films and that applied in TFTs were the first studied in the literature

High stability mechanisms of quinary indium gallium zinc aluminum oxide multicomponent oxide films and thin film transistors

Energy Technology Data Exchange (ETDEWEB)

Lee, Ching-Ting, E-mail: ctlee@ee.ncku.edu.tw; Lin, Yung-Hao; Lin, Jhong-Ham [Institute of Microelectronics, Department of Electrical Engineering, Research Center for Energy Technology and Strategy (RCETS), National Cheng Kung University, Tainan, Taiwan (China)

2015-01-28

Quinary indium gallium zinc aluminum oxide (IGZAO) multicomponent oxide films were deposited using indium gallium zinc oxide (IGZO) target and Al target by radio frequency magnetron cosputtering system. An extra carrier transport pathway could be provided by the 3 s orbitals of Al cations to improve the electrical properties of the IGZO films, and the oxygen instability could be stabilized by the strong Al-O bonds in the IGZAO films. The electron concentration change and the electron mobility change of the IGZAO films for aging time of 10 days under an air environment at 40 °C and 75% humidity were 20.1% and 2.4%, respectively. The experimental results verified the performance stability of the IGZAO films. Compared with the thin film transistors (TFTs) using conventional IGZO channel layer, in conducting the stability of TFTs with IGZAO channel layer, the transconductance g{sub m} change, threshold voltage V{sub T} change, and the subthreshold swing S value change under the same aging condition were improved to 7.9%, 10.5%, and 14.8%, respectively. Furthermore, the stable performances of the IGZAO TFTs were also verified by the positive gate bias stress. In this research, the quinary IGZAO multicomponent oxide films and that applied in TFTs were the first studied in the literature.

Passivation and corrosion behaviours of cobalt and cobalt-chromium-molybdenum alloy

International Nuclear Information System (INIS)

Metikos-Hukovic, M.; Babic, R.

2007-01-01

Passivation and corrosion behaviour of the cobalt and cobalt-base alloy Co30Cr6Mo was studied in a simulated physiological solution containing chloride and bicarbonate ions and with pH of 6.8. The oxido-reduction processes included solid state transformations occurring at the cobalt/electrolyte interface are interpreted using theories of surface electrochemistry. The dissolution of cobalt is significantly suppressed by alloying it with chromium and molybdenum, since the alloy exhibited 'chromium like' passivity. The structural and protective properties of passive oxide films formed spontaneously at the open circuit potential or during the anodic polarization were studied using electrochemical impedance spectroscopy in the wide frequency range

Electrical and optical properties of zinc oxide: thin films

International Nuclear Information System (INIS)

Zuhairusnizam Md Darus; Abdul Jalil Yeop Majlis; Anis Faridah Md Nor; Burhanuddin Kamaluddin

1992-01-01

Zinc oxide films have been prepared by high temperature oxidation of thermally evaporated zinc films on glass substrates. The resulting films are characterized using X-ray diffraction, optical absorption and electrical conductivity measurements. These zinc oxide films are very transparent and photoconductive

Oxidation of ruthenium thin films using atomic oxygen

Energy Technology Data Exchange (ETDEWEB)

McCoy, A.P.; Bogan, J.; Brady, A.; Hughes, G.

2015-12-31

In this study, the use of atomic oxygen to oxidise ruthenium thin films is assessed. Atomic layer deposited (ALD) ruthenium thin films (~ 3 nm) were exposed to varying amounts of atomic oxygen and the results were compared to the impact of exposures to molecular oxygen. X-ray photoelectron spectroscopy studies reveal substantial oxidation of metallic ruthenium films to RuO{sub 2} at exposures as low as ~ 10{sup 2} L at 575 K when atomic oxygen was used. Higher exposures of molecular oxygen resulted in no metal oxidation highlighting the benefits of using atomic oxygen to form RuO{sub 2}. Additionally, the partial oxidation of these ruthenium films occurred at temperatures as low as 293 K (room temperature) in an atomic oxygen environment. - Highlights: • X-ray photoelectron spectroscopy study of the oxidation of Ru thin films • Oxidation of Ru thin films using atomic oxygen • Comparison between atomic oxygen and molecular oxygen treatments on Ru thin films • Fully oxidised RuO{sub 2} thin films formed with low exposures to atomic oxygen.

Catalytic oxidation of albendazole using molybdenum supported on carbon nanotubes as catalyst

International Nuclear Information System (INIS)

Sun-Kou, Maria del Rosario; Vega Carrasco, Edgar R.; Picasso Escobar, Gino I.

2013-01-01

The catalytic oxidation reaction of the thioether group (-S-) in the structure to the drug albendazole (C 12 H 15 N 3 O 2 S) was studied in order to obtain a pharmacologically active molecule known as albendazole sulfoxide. With this purpose, three heterogeneous catalysts were prepared using molybdenum (Mo) as active phase and carbon nanotubes as a multiple-layer catalyst support. The incorporation of the active phase was performed by wet impregnation, with subsequent calcination for 4 hours at 400 o C. For the catalytic oxidation reaction was employed hydrogen peroxide-urea (H 2 NCONH 2 ·H 2 O 2 ) as oxidizing agent and methanol (CH 3 OH) as reaction medium. The textural and morphology characterization of carbon nanoparticles and catalysts was carried out by adsorption-desorption of N 2 (BET) and scanning electron microscopy (SEM). The identification and quantification of the reaction products were followed by Fourier transform infrared spectroscopy (FTIR) and high performance liquid chromatography (HPLC), respectively. With the yield, selectivity and conversion higher than 90% after 60 minutes of reaction, albendazole sulphoxide was obtained as major product of oxidation reaction. (author)

Synthesis and characterization of some reduced ternary and quaternary molybdenum oxide phases with strong metal-metal bonds

International Nuclear Information System (INIS)

Lii, K.H.

1985-10-01

In the course of our research on reduced ternary and quaternary molybdenum oxides, very interesting compounds with strong metal-metal bonds were discovered. Among these solid-state materials are found discrete cluster arrays and structures with extended metal-metal bonding. Further study in this system has revealed that many new structures exist in this new realm. The synthesis, structures, bonding, and properties of these new oxides, which are briefly summarized in tabular form, are presented in this thesis. 144 refs., 63 figs., 79 tabs

Influence of Chromium and Molybdenum on the Corrosion of Nickel Based Alloys

International Nuclear Information System (INIS)

Hayes, J R; Gray, J; Szmodis, A W; Orme, C A

2005-01-01

The addition of chromium and molybdenum to nickel creates alloys with exceptional corrosion resistance in a diverse range of environments. This study examines the complementary roles of Cr and Mo in Ni alloy passivation. Four nickel alloys with varying amounts of chromium and molybdenum were studied in 1 molar salt solutions over a broad pH range. The passive corrosion and breakdown behavior of the alloys suggests that chromium is the primary element influencing general corrosion resistance. The breakdown potential was nearly independent of molybdenum content, while the repassivation potential is strongly dependant on the molybdenum content. This indicates that chromium plays a strong role in maintaining the passivity of the alloy, while molybdenum acts to stabilize the passive film after a localized breakdown event

Chitosan/graphene oxide biocomposite film from pencil rod

Science.gov (United States)

Gea, S.; Sari, J. N.; Bulan, R.; Piliang, A.; Amaturrahim, S. A.; Hutapea, Y. A.

2018-03-01

Graphene Oxide (GO) has been succesfully synthesized using Hummber method from graphite powder of pencil rod. The excellent solubility of graphene oxide (GO)in water imparts its feasibilty as new filler for reinforcement hydrophilic biopolymers. In this research, the biocomposite film was fabricated from chitosan/graphene oxide. The characteristics of graphene oxide were investigated using Fourier Transform Infrared (FT-IR) and X-ray Diffraction (XRD). The results of the XRD showed graphene structur in 2θ, appeared at 9.0715°with interlayer spacing was about 9.74063Å. Preparation films with several variations of chitosan/graphene oxide was done by casting method and characterized by mechanical and morphological analysis. The mechanical properties of the tensile test in the film show that the film CS/GO (85: 15)% has the optimum Young’s modulus size of 2.9 GPa compared to other variations of CS / GO film. Morphological analysis film CS/GO (85:15)% by Scanning Electron Microscopy (SEM), the obtained biocomposites film showed fine dispersion of GO in the CS matrix and could mix each other homogeneously.

Interface and oxide traps in high-κ hafnium oxide films

International Nuclear Information System (INIS)

Wong, H.; Zhan, N.; Ng, K.L.; Poon, M.C.; Kok, C.W.

2004-01-01

The origins of the interface trap generation and the effects of thermal annealing on the interface and bulk trap distributions are studied in detail. We found that oxidation of the HfO 2 /Si interface, removal of deep trap centers, and crystallization of the as-deposited film will take place during the post-deposition annealing (PDA). These processes will result in the removal of interface traps and deep oxide traps and introduce a large amount of shallow oxide traps at the grain boundaries of the polycrystalline film. Thus, trade-off has to be made in considering the interface trap density and oxide trap density when conducting PDA. In addition, the high interface trap and oxide trap densities of the HfO 2 films suggest that we may have to use the SiO 2 /HfO 2 stack or hafnium silicate structure for better device performance

Electrochemical investigations of ion-implanted oxide films

International Nuclear Information System (INIS)

Schultze, J.W.; Danzfuss, B.; Meyer, O.; Stimming, U.

1985-01-01

Oxide films (passive films) of 40-50 nm thickness were prepared by anodic polarization of hafnium and titanium electrodes up to 20 V. Multiple-energy ion implantation of palladium, iron and xenon was used in order to obtain modified films with constant concentration profiles of the implanted ions. Rutherford backscattering, X-ray photoelectron spectroscopy measurements and electrochemical charging curves prove the presence of implanted ions, but electrochemical and photoelectrochemical measurements indicate that the dominating effect of ion implantation is the disordering of the oxide film. The capacity of hafnium electrodes increases as a result of an increase in the dielectric constant D. For titanium the Schottky-Mott analysis shows that ion implantation causes an increase in D and the donor concentration N. Additional electronic states in the band gap which are created by the implantation improve the conductivity of the semiconducting or insulating films. This is seen in the enhancement of electron transfer reactions and its disappearance during repassivation and annealing. Energy changes in the band gap are derived from photoelectrochemical measurements; the absorption edge of hafnium oxide films decreases by approximately 2 eV because of ion implantation, but it stays almost constant for titanium oxide films. All changes in electrochemical behavior caused by ion implantation show little variation with the nature of the implanted ion. Hence the dominating effect seems to be a disordering of the oxide. (Auth.)

Reduction and immobilization of molybdenum by Desulfovibrio desulfuricans

Energy Technology Data Exchange (ETDEWEB)

Tucker, M.D.; Barton, L.L.; Thomson, B.M. [Sandia National Laboratories, Albuquerque, NM (United States)

1997-07-01

Molybdenum contamination of groundwater occurs through activities such as molybdenum and copper mining and processing, shale oil production and power generation from coal-fired power plants. The mobility of Mo in the environment is strongly dependent on its chemical oxidation state. Under oxidizing conditions, Mo occurs as highly soluble and mobile Mo(VI) and Mo(V) compounds. However, under reducing conditions Mo usually forms insoluble Mo(IV) phases. The objective of this study was to demonstrate the ability of the sulfate-reducing bacterium, Desulfovibrio desulfuricans, to reduce Mo(IV) to Mo(IV) in anaerobic environments. Molybdenum-VI was reduced to Mo(IV) by washed cells of D. desulfuricans suspended in bicarbonate buffer solution with either lactate or H{sub 2} as the electron donor and Mo(VI) as the electron acceptor. Molybdenum-VIi reduction by D. desulfuricans in the presence of sulfide resulted in the extracelluar precipitation of the mineral molybdenite. Molybdenum-VI reduction did not occur in the absence of an electron donor or in the presence of heat-killed cells of D. desulfuricans. The results indicate that enzymatic reduction of Mo(VI) by sulfate-reducing bacteria may contribute to the accumulation of Mo(IV) in anaerobic environments and that there organisms may be useful for removing soluble Mo from contaminated water. 20 refs., 6 figs., 4 tabs.

Regularly arranged indium islands on glass/molybdenum substrates upon femtosecond laser and physical vapor deposition processing

Energy Technology Data Exchange (ETDEWEB)

Ringleb, F.; Eylers, K.; Teubner, Th.; Boeck, T., E-mail: torsten.boeck@ikz-berlin.de [Leibniz-Institute for Crystal Growth, Max-Born-Straße 2, Berlin 12489 (Germany); Symietz, C.; Bonse, J.; Andree, S.; Krüger, J. [Bundesanstalt für Materialforschung und-prüfung (BAM), Unter den Eichen 87, Berlin 12205 (Germany); Heidmann, B.; Schmid, M. [Department of Physics, Freie Universität Berlin, Arnimalle 14, Berlin 14195 (Germany); Nanooptical Concepts for PV, Helmholtz Zentrum Berlin, Hahn-Meitner-Platz 1, Berlin 14109 (Germany); Lux-Steiner, M. [Nanooptical Concepts for PV, Helmholtz Zentrum Berlin, Hahn-Meitner-Platz 1, Berlin 14109 (Germany); Heterogeneous Material Systems, Helmholtz Zentrum Berlin, Hahn-Meitner-Platz 1, Berlin 14109 (Germany)

2016-03-14

A bottom-up approach is presented for the production of arrays of indium islands on a molybdenum layer on glass, which can serve as micro-sized precursors for indium compounds such as copper-indium-gallium-diselenide used in photovoltaics. Femtosecond laser ablation of glass and a subsequent deposition of a molybdenum film or direct laser processing of the molybdenum film both allow the preferential nucleation and growth of indium islands at the predefined locations in a following indium-based physical vapor deposition (PVD) process. A proper choice of laser and deposition parameters ensures the controlled growth of indium islands exclusively at the laser ablated spots. Based on a statistical analysis, these results are compared to the non-structured molybdenum surface, leading to randomly grown indium islands after PVD.

Study on creep-fatigue evaluation of chrome-molybdenum steel

International Nuclear Information System (INIS)

Aoto, Kazumi; Wada, Yusaku

1993-01-01

Though chrome-molybdenum steel has quite different basic material properties from austenitic stainless steel, the life fraction rule based on an advanced ductility exhaustion theory proposed for SUS304 is able to give proper prediction for creep-fatigue life of chrome-molybdenum steel. The applicability of the present evaluation method to chrome-molybdenum steel is validated by both mechanical study and micro-structural observation. The mechanism of creep-fatigue failure of Mod.9Cr-1Mo(NT) is one of the most controversial subjects among researchers. However, it is clarified in this report that creep-fatigue damage of this material under actual loading conditions is dominated by creep-cavitation of grain boundaries as same way as that of austenitic stainless steel. Furthermore, for the life reduction of low cycle fatigue of chrome-molybdenum steel with compression-side strain hold, both effects of mean stress and oxide-wedge are denied and it is insisted that the acceleration of fatigue-crack propagation is occurred by oxide-progress location and its thickness. (author)

Adhesion analysis of polycrystalline diamond films on molybdenum by means of scratch, indentation and sand abrasion testing

Energy Technology Data Exchange (ETDEWEB)

Buijnsters, J.G. [Applied Physics, IMM, Department of Applied Physics, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen (Netherlands); Shankar, P. [Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam-603 102 (India); Enckevort, W.J.P. van [Solid State Chemistry, IMM, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen (Netherlands); Schermer, J.J. [Experimental Solid State Physics III, IMM, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen (Netherlands); Meulen, J.J. ter [Applied Physics, IMM, Department of Applied Physics, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen (Netherlands)]. E-mail: htmeulen@sci.kun.nl

2005-03-01

Diamond films have been grown by hot-filament chemical vapour deposition (CVD) on molybdenum substrates under different growth conditions. The films grown with increasing substrate temperatures show a higher interconnection of diamond grains, whereas increasing methane concentrations in the 0.5-4.0% range lead to a transition from micro- towards nanocrystalline films. X-ray diffraction analysis shows Mo{sub 2}C interlayer formation. Indentation, scratch and sand erosion tests are used to evaluate the adhesion strength of the diamond films. Using steel ball indenters (diameter 750 {mu}m), indentation and scratch adhesion tests are performed up to final loads of 200 N. Upon indentation, the load values at which diamond film failure such as flaking and detachment is first observed, increase for increasing temperatures in the deposition temperature range of 450-850 deg C. The scratch adhesion tests show critical load values in the range of 16-40 N normal load for films grown for 4 h. In contrast, diamond films grown for 24 h at a methane concentration of 0.5% do not show any failure at all upon scratching up to 75 N. Film failure upon indenting and scratching is also found to decrease for increasing methane concentration in the CVD gas mixture. The sand abrasion tests show significant differences in coating failure for films grown at varying CH{sub 4}/H{sub 2} ratios. In contrast to the other tests, here best coating performance is observed for the films deposited with a methane concentration of 4%.

Surface and sub-surface thermal oxidation of thin ruthenium films

Energy Technology Data Exchange (ETDEWEB)

Coloma Ribera, R.; Kruijs, R. W. E. van de; Yakshin, A. E.; Bijkerk, F. [MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede (Netherlands); Kokke, S.; Zoethout, E. [FOM Dutch Institute for Fundamental Energy Research (DIFFER), P.O. Box 1207, 3430 BE Nieuwegein (Netherlands)

2014-09-29

A mixed 2D (film) and 3D (nano-column) growth of ruthenium oxide has been experimentally observed for thermally oxidized polycrystalline ruthenium thin films. Furthermore, in situ x-ray reflectivity upon annealing allowed the detection of 2D film growth as two separate layers consisting of low density and high density oxides. Nano-columns grow at the surface of the low density oxide layer, with the growth rate being limited by diffusion of ruthenium through the formed oxide film. Simultaneously, with the growth of the columns, sub-surface high density oxide continues to grow limited by diffusion of oxygen or ruthenium through the oxide film.

Fabrication and electrical resistivity of Mo-doped VO2 thin films coated on graphite conductive plates by a sol-gel method

Energy Technology Data Exchange (ETDEWEB)

Choi, W.; Jung, H.M.; Um, S. [Hanyang Univ., Seoul (Korea, Republic of). School of Mechanical Engineering

2008-07-01

Vanadium oxides (VO2) can be used in optical devices, thermochromic smart windows and sensors. This paper reported on a study in which vanadium pentoxide (V2O5) powder was prepared and mixed with Molybdenum Oxides (MoO3) to form Mo-doped and -undoped VO2 thin films by a sol-gel method on graphite conductive substrates. The micro-structure and chemical compositions of the Mo-doped and -undoped VO2 thin films was investigated using X-Ray diffraction and scanning electron microscopy. Changes in electrical resistivity were measured as a function of the stoichiometric compositions between vanadium and molybdenum. In this study. Mo-doped and -undoped VO2 thin films showed the typical metal to insulator transition (MIT), where temperature range could be adjusted by modifying the dopant atomic ratio. The through-plane substrate structure of the Mo-doped layer influences the electrical resistivity of the graphite substrate. As the amount of the molybdenum increases, the electrical resistivity of the graphite conductive substrate decreases in the lower temperature range below the freezing point of water. The experimental results showed that if carefully controlled, thermal dissipation of VO2 thin films can be used as a self-heating source to melt frozen water with the electrical current flowing through the graphite substrate. 3 refs., 3 figs.

Electrochemistry of hydrous oxide films

International Nuclear Information System (INIS)

Burke, L.D.; Lyons, M.E.G.

1986-01-01

The formation, acid-base properties, structural aspects, and transport processes of hydrous oxide films are discussed. Classical and nonclassical theoretical models of the oxide-solution interface are compared. Monolayer oxidation, behavior, and crystal growth of oxides on platinum, palladium, gold, iridium, rhodium, ruthenium, and some non-noble metals, including tungsten, are reviewed and compared

NEXAFS characterization and reactivity studies of bimetallic vanadium molybdenum oxynitride hydrotreating catalysts

Energy Technology Data Exchange (ETDEWEB)

Kapoor, R.; Oyama, S.T. [Virginia Polytechnic Inst., Blacksburg, VA (United States); Fruehberger, B.; Chen, J.G. [Exxon Research and Engineering Company, Annandale, NJ (United States)

1997-02-27

The surface and bulk compositions of vanadium molybdenum oxynitride (V{sub 2}MoO{sub 1.7}N{sub 2.4}), prepared by temperature-programmed reaction (TPR) of vanadium molybdenum oxide (V{sub 2}MoO{sub 8}) with ammonia, have been characterized using near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. The NEXAFS data were recorded at the K-edges of nitrogen and oxygen, the L-edge of vanadium, and the M-edge of molybdenum. The nitrogen K-edge region of V-Mo oxynitride shows the characteristic NEXAFS features of early-transition-metal nitrides, although these features are different from those of either VN or Mo{sub 2}N. Furthermore, comparison of the electron yield and fluorescence yield measurements also reveals that the oxidation state is different for vanadium near the surface region and for vanadium in the bulk, which is estimated to be 2.8 {+-} 0.3 and 3.8 {+-} 0.3, respectively. The oxidation state of bulk molybdenum is also estimated to be 4.4 {+-} 0.3. The X-ray diffraction pattern shows that the bulk phase of the bimetallic oxide is different from the pure monometallic oxide phases but the oxynitride has a cubic structure that resembles the pure vanadium and molybdenum nitride phases. The V-Mo oxide as prepared shows a preferential orientation of [001] crystallographic planes which is lost during the nitridation process. This shows that the solid state transformation V{sub 2}MoO{sub 8} {yields} V{sub 2}MoO{sub 1.7}N{sub 2.4} is not topotactic. 27 refs., 8 figs., 1 tab.

Electrochromism of the electroless deposited cuprous oxide films

International Nuclear Information System (INIS)

Neskovska, R.; Ristova, M.; Velevska, J.; Ristov, M.

2007-01-01

Thin cuprous oxide films were prepared by a low cost, chemical deposition (electroless) method onto glass substrates pre-coated with fluorine doped tin oxide. The X-ray diffraction pattern confirmed the Cu 2 O composition of the films. Visible transmittance spectra of the cuprous oxide films were studied for the as-prepared, colored and bleached films. The cyclic voltammetry study showed that those films exhibited cathode coloring electrochromism, i.e. the films showed change of color from yellowish to black upon application of an electric field. The transmittance across the films for laser light of 670 nm was found to change due to the voltage change for about 50%. The coloration memory of those films was also studied during 6 h, ex-situ. The coloration efficiency at 670 nm was calculated to be 37 cm 2 /C

Real-time imaging, spectroscopy, and structural investigation of cathodic plasma electrolytic oxidation of molybdenum

Energy Technology Data Exchange (ETDEWEB)

Stojadinović, Stevan, E-mail: sstevan@ff.bg.ac.rs; Tadić, Nenad; Šišović, Nikola M.; Vasilić, Rastko [Faculty of Physics, University of Belgrade, Studentski trg 12-16, 11000 Belgrade (Serbia)

2015-06-21

In this paper, the results of the investigation of cathodic plasma electrolytic oxidation (CPEO) of molybdenum at 160 V in a mixed solution of borax, water, and ethylene glycol are presented. Real-time imaging and optical emission spectroscopy were used for the characterization of the CPEO. During the process, vapor envelope is formed around the cathode and strong electric field within the envelope caused the generation of plasma discharges. The spectral line shape analysis of hydrogen Balmer line H{sub β} (486.13 nm) shows that plasma discharges are characterized by the electron number density of about 1.4 × 10{sup 21 }m{sup −3}. The electron temperature of 15 000 K was estimated by measuring molybdenum atomic lines intensity. Surface morphology, chemical, and phase composition of coatings formed by CPEO were characterized by scanning electron microscopy with energy dispersive x-ray spectroscopy and x-ray diffraction. The elemental components of CPEO coatings are Mo and O and the predominant crystalline form is MoO{sub 3}.

Investigation of ferromagnetism in oxygen deficient hafnium oxide thin films

Energy Technology Data Exchange (ETDEWEB)

Hildebrandt, Erwin; Kurian, Jose; Krockenberger, Yoshiharu; Alff, Lambert [Institut fuer Materialwissenschaft, TU Darmstadt (Germany); Suter, Andreas [PSI, Villingen (Switzerland); Wilhelm, Fabrice; Rogalev, Andrei [ESRF, Grenoble (France)

2008-07-01

Oxygen deficient thin films of hafnium oxide were grown on single crystal r-cut and c-cut sapphire by reactive molecular beam epitaxy. RF-activated oxygen was used for the in situ oxidation of hafnium oxide thin films. Oxidation conditions were varied substantially in order to create oxygen deficiency in hafnium oxide films intentionally. The films were characterized by X-ray and magnetic measurements. X-ray diffraction studies show an increase in lattice parameter with increasing oxygen deficiency. Oxygen deficient hafnium oxide thin films also showed a decreasing bandgap with increase in oxygen deficiency. The magnetisation studies carried out with SQUID did not show any sign of ferromagnetism in the whole oxygen deficiency range. X-ray magnetic circular dichroism measurements also confirmed the absence of ferromagnetism in oxygen deficient hafnium oxide thin films.

Synthesis of molybdenum borides and molybdenum silicides in molten salts and their oxidation behavior in an air-water mixture

NARCIS (Netherlands)

Kuznetsov, S.A.; Kuznetsova, S.V.; Rebrov, E.V.; Mies, M.J.M.; Croon, de M.H.J.M.; Schouten, J.C.

2005-01-01

The formation of various coatings in molybdenum-boron and molybdenum-silicon systems was investigated. Boronizing and siliciding treatments were conducted in molten salts under inert gas atm. in the 850-1050 DegC temp. range for 7 h. The presence of boride (e.g. Mo2B, MoB, Mo2B5) and silicide

Coaxial silver nanowire network core molybdenum oxide shell supercapacitor electrodes

International Nuclear Information System (INIS)

Yuksel, Recep; Coskun, Sahin; Unalan, Husnu Emrah

2016-01-01

We present a new hybrid material composed of molybdenum (IV) oxide (MoO 2 ) shell on highly conducting silver nanowire (Ag NW) core in the network form for the realization of coaxial Ag NW/MoO 2 nanocomposite supercapacitor electrodes. Ag NWs were simply spray coated onto glass substrates to form conductive networks and conformal MoO 2 layer was electrodeposited onto the Ag NW network to create binder-free coaxial supercapacitor electrodes. Combination of Ag NWs and pseudocapacitive MoO 2 generated an enhanced electrochemical energy storage capacity and a specific capacitance of 500.7 F/g was obtained at a current density of 0.25 A/g. Fabricated supercapacitor electrodes showed excellent capacity retention after 5000 cycles. The methods and the design investigated herein open a wide range of opportunities for nanowire based coaxial supercapacitors.

Unidirectional oxide hetero-interface thin-film diode

International Nuclear Information System (INIS)

Park, Youngmin; Lee, Eungkyu; Lee, Jinwon; Lim, Keon-Hee; Kim, Youn Sang

2015-01-01

The unidirectional thin-film diode based on oxide hetero-interface, which is well compatible with conventional thin-film fabrication process, is presented. With the metal anode/electron-transporting oxide (ETO)/electron-injecting oxide (EIO)/metal cathode structure, it exhibits that electrical currents ohmically flow at the ETO/EIO hetero-interfaces for only positive voltages showing current density (J)-rectifying ratio of ∼10 5 at 5 V. The electrical properties (ex, current levels, and working device yields) of the thin-film diode (TFD) are systematically controlled by changing oxide layer thickness. Moreover, we show that the oxide hetero-interface TFD clearly rectifies an AC input within frequency (f) range of 10 2  Hz < f < 10 6  Hz, providing a high feasibility for practical applications

Unidirectional oxide hetero-interface thin-film diode

Energy Technology Data Exchange (ETDEWEB)

Park, Youngmin; Lee, Eungkyu; Lee, Jinwon; Lim, Keon-Hee [Program in Nano Science and Technology, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 151-742 (Korea, Republic of); Kim, Youn Sang, E-mail: younskim@snu.ac.kr [Program in Nano Science and Technology, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 151-742 (Korea, Republic of); Advanced Institute of Convergence Technology, Gyeonggi-do 443-270 (Korea, Republic of)

2015-10-05

The unidirectional thin-film diode based on oxide hetero-interface, which is well compatible with conventional thin-film fabrication process, is presented. With the metal anode/electron-transporting oxide (ETO)/electron-injecting oxide (EIO)/metal cathode structure, it exhibits that electrical currents ohmically flow at the ETO/EIO hetero-interfaces for only positive voltages showing current density (J)-rectifying ratio of ∼10{sup 5} at 5 V. The electrical properties (ex, current levels, and working device yields) of the thin-film diode (TFD) are systematically controlled by changing oxide layer thickness. Moreover, we show that the oxide hetero-interface TFD clearly rectifies an AC input within frequency (f) range of 10{sup 2} Hz < f < 10{sup 6} Hz, providing a high feasibility for practical applications.

Characterization of ultrasonic spray pyrolysed ruthenium oxide thin films

Energy Technology Data Exchange (ETDEWEB)

Patil, P.S.; Ennaoui, E.A.; Lokhande, C.D.; Mueller, M.; Giersig, M.; Diesner, K.; Tributsch, H. [Hahn-Meitner-Institut Berlin GmbH (Germany). Bereich Physikalische Chemie

1997-11-21

The ultrasonic spray pyrolysis (USP) technique was employed to deposit ruthenium oxide thin films. The films were prepared at 190 C substrate temperature and further annealed at 350 C for 30 min in air. The films were 0.22 {mu} thick and black grey in color. The structural, compositional and optical properties of ruthenium oxide thin films are reported. Contactless transient photoconductivity measurement was carried out to calculate the decay time of excess charge carriers in ruthenium oxide thin films. (orig.) 28 refs.

Photoinduced hydrophobic surface of graphene oxide thin films

International Nuclear Information System (INIS)

Zhang Xiaoyan; Song Peng; Cui Xiaoli

2012-01-01

Graphene oxide (GO) thin films were deposited on transparent conducting oxide substrates and glass slides by spin coating method at room temperature. The wettability of GO thin films before and after ultraviolet (UV) irradiation was characterized with water contact angles, which increased from 27.3° to 57.6° after 3 h of irradiation, indicating a photo-induced hydrophobic surface. The UV–vis absorption spectra, Raman spectroscopy, X-ray photoelectron spectroscopy, and conductivity measurements of GO films before and after UV irradiation were taken to study the mechanism of photoinduced hydrophobic surface of GO thin films. It is demonstrated that the photoinduced hydrophobic surface is ascribed to the elimination of oxygen-containing functional groups on GO molecules. This work provides a simple strategy to control the wettability properties of GO thin films by UV irradiation. - Highlights: ► Photoinduced hydrophobic surface of graphene oxide thin films has been demonstrated. ► Elimination of oxygen-containing functional groups in graphene oxide achieved by UV irradiation. ► We provide novel strategy to control surface wettability of GO thin films by UV irradiation.

Oxidation phase growth diagram of vanadium oxides film fabricated by rapid thermal annealing

Institute of Scientific and Technical Information of China (English)

Tamura KOZO; Zheng-cao LI; Yu-quan WANG; Jie NI; Yin HU; Zheng-jun ZHANG

2009-01-01

Thermal evaporation deposited vanadium oxide films were annealed in air by rapid thermal annealing (RTP). By adjusting the annealing temperature and time, a series of vanadium oxide films with various oxidation phases and surface morphologies were fabricated, and an oxidation phase growth diagram was established. It was observed that different oxidation phases appear at a limited and continuous annealing condition range, and the morphologic changes are related to the oxidation process.

Growth of Cu thin films by the successive ionic layer adsorption and reaction (SILAR) method

International Nuclear Information System (INIS)

Lindroos, S.; Ruuskanen, T.; Ritala, M.; Leskelae, M.

2004-01-01

Copper thin films were grown on reduced indium tin oxide, molybdenum and polymer substrates using successive ionic layer adsorption and reaction (SILAR) method. Copper films were grown sequentially in a controlled way using simple copper salt and basic solution of formaldehyde as precursors. The copper films were polycrystalline with no preferred orientation as characterised by X-ray diffraction. On all substrates, the growth was clearly island growth in the beginning but after the whole surface was covered, the growth was more homogeneous

Effect of hydrogen on stresses in anodic oxide film on titanium

International Nuclear Information System (INIS)

Kim, Joong-Do; Pyun, Su-Il; Seo, Masahiro

2003-01-01

Stresses in anodic oxide film on titanium thin film/glass electrode in pH 8.4 borate solution were investigated by a bending beam method. The increases in compressive stress observed with cathodic potential sweeps after formation of anodic oxide film were attributed to the volume expansion due to the compositional change of anodic oxide film from TiO 2 to TiO 2-x (OH) x . The instantaneous responses of changes in stress, Δσ, in the anodic oxide film to potential steps demonstrated the reversible characteristic of the TiO 2-x (OH) x formation reaction. In contrast, the transient feature of Δσ for the titanium without anodic oxide film represented the irreversible formation of TiH x at the metal/oxide interphase. The large difference in stress between with and without the oxide film, has suggested that most of stresses generated during the hydrogen absorption/desorption reside in the anodic oxide film. A linear relationship between changes in stress, Δ(Δσ) des , and electric charge, ΔQ des , during hydrogen desorption was found from the current and stress transients, manifesting that the stress changes were crucially determined by the amount of hydrogen desorbed from the oxide film. The increasing tendency of -Δ(Δσ) des with increasing number of potential steps and film formation potential were discussed in connection with the increase in desorption amount of hydrogen in the oxide film with increasing absorption/desorption cycles and oxide film thickness

SPH based modelling of oxide and oxide film formation in gravity die castings

International Nuclear Information System (INIS)

Ellingsen, K; M'Hamdi, M; Coudert, T

2015-01-01

Gravity die casting is an important casting process which has the capability of making complicated, high-integrity components for e.g. the automotive industry. Oxides and oxide films formed during filling affect the cast product quality. The Smoothed particle hydrodynamics (SPH) method is particularly suited to follow complex flows. The SPH method has been used to study filling of a gravity die including the formation and transport of oxides and oxide films for two different filling velocities. A low inlet velocity leads to a higher amount of oxides and oxide films in the casting. The study demonstrates the usefulness of the SPH method for an increased understanding of the effect of different filling procedures on the cast quality. (paper)

Influence of substrate material on the microstructure and optical properties of hot wall deposited SnS thin films

International Nuclear Information System (INIS)

Bashkirov, S.A.; Gremenok, V.F.; Ivanov, V.A.; Shevtsova, V.V.; Gladyshev, P.P.

2015-01-01

Tin monosulfide SnS raises an interest as a promising material for photovoltaics. The influence of the substrate material on the microstructure and optical properties of SnS thin films with [111] texture obtained by hot wall vacuum deposition on glass, molybdenum and indium tin oxide substrates is reported. The lattice parameters for layers grown on different substrates were determined by X-ray diffraction and their deviations from the data reported in the literature for single α-SnS crystals were discussed. The change in the degree of preferred orientation of the films depending on the substrate material is observed. The direct nature of the optical transitions with the optical band gap of 1.15 ± 0.01 eV is reported. - Highlights: • SnS thin films were hot wall deposited on glass, molybdenum and indium tin oxide. • Physical properties of the films were studied with respect to the substrate type. • The SnS lattice parameter deviations were observed and the explanation was given. • The direct optical transitions with the band gap of 1.15 ± 0.01 eV were observed

Influence of ion-to-atom ratio on the microstructure of evaporated molybdenum thin films grown using low energy argon ions

Energy Technology Data Exchange (ETDEWEB)

Yadav, Praveen Kumar, E-mail: praveenyadav@rrcat.gov.in; Nayak, Maheswar; Rai, Sanjay Kumar; Lodha, Gyanendra Singh [X-ray Optics Section, Indus Synchrotrons Utilization Division, Raja Ramanna Centre for Advanced Technology, Indore 452013 (India); Sant, Tushar; Sharma, Surinder Mohan [High Pressure and Synchrotron Radiation Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Mukherjee, Chandrachur [Mechanical and Optical Support Section, Raja Ramanna Centre for Advanced Technology, Indore 452013 (India)

2014-03-15

The authors report the effect of argon ion to molybdenum atom ratio (r) on the microstructure of low energy (70 eV) argon ion assisted electron beam evaporated Mo thin films. Surface roughness, morphology, and crystallinity of Mo films are found to strongly depend on “r.” Increase of “r” from 0 to 100 induces gradual loss in crystallinity, reduction in surface roughness and systematic increase in density of the film. For “r” ∼ 100, average atomic density of the film approaches the bulk value (97%) with lowest surface roughness. Further, increasing “r” up to 170 reduces the atomic density, increases roughness, and increase in crystallinity induced by low energy Ar ion beam. The observed surface roughness and grain size determined by x-ray reflectivity and glancing incidence x-ray diffraction correlate well with atomic force microscopy measurements. This study demonstrates that for r = 100 one gets lowest roughness Mo film with highest density and nearly amorphous microstructure. The growth model is discussed by structural zone model.

Formation of corrosion-resistant oxide film on uranium

International Nuclear Information System (INIS)

Petit, G.S.

1976-01-01

A vacuum heat-treatment method was developed for coating metallic uranium with an adherent protective film of uranium oxide. The film is prepared by vacuum heat-treating the metallic uranium at 625 0 C for 1 h while controlling the amount of oxygen being metered into the furnace. Uranium coupons with the protective film were exposed for several hundred hours in a corrosion test bath at 95 0 C and 100 percent RH without corroding. Film thicknesses ranging from 5 to 25 μm (0.0002 to 0.001 in.) were prepared and corrosion tested; the film thickness can be controlled to less than +-2.5 μm (+-0.0001 in.). The oxide film is hard, nonwetting, and very adherent. The resulting surface finish of the metal is equivalent to that of the original finish. The advantages of the oxide films over other protective coatings are given. 12 fig

Hydrotreatment activities of supported molybdenum nitrides and carbides

Energy Technology Data Exchange (ETDEWEB)

Dolce, G.M.; Savage, P.E.; Thompson, L.T. [University of Michigan, Ann Arbor, MI (United States). Dept. of Chemical Engineering

1997-05-01

The growing need for alternative sources of transportation fuels encourages the development of new hydrotreatment catalysts. These catalysts must be active and more hydrogen efficient than the current commercial hydrotreatment catalysts. Molybdenum nitrides and carbides are attractive candidate materials possessing properties that are comparable or superior to those of commercial sulfide catalysts. This research investigated the catalytic properties of {gamma}-Al{sub 2}O{sub 3}-supported molybdenum nitrides and carbides. These catalysts were synthesized via temperature-programmed reaction of supported molybdenum oxides with ammonia or methane/hydrogen mixtures. Phase constituents and compositions were determined by X-ray diffraction, elemental analysis, and neutral activation analysis. Oxygen chemisorption was used to probe the surface properties of the catalysts. Specific activities of the molybdenum nitrides and carbides were competitive with those of a commercial sulfide catalyst for hydrodenitrogenation (HDN), hydrodesulfurization (HDS), and hydrodeoxygenation (HDO). For HDN and HDS, the catalytic activity on a molybdenum basis was a strong inverse function of the molybdenum loading. Product distributions of the HDN, HDO and HDS of a variety of heteroatom compounds indicated that several of the nitrides and carbides were more hydrogen efficient than the sulfide catalyst. 35 refs., 8 figs., 7 tabs.

Study of film graphene/graphene oxide obtained by partial reduction chemical of oxide graphite

International Nuclear Information System (INIS)

Gascho, J.L.S.; Costa, S.F.; Hoepfner, J.C.; Pezzin, S.H.

2014-01-01

This study investigated the morphology of graphene/graphene oxide film obtained by partial chemical reduction of graphite oxide (OG) as well as its resistance to solvents. Films of graphene/graphene oxide are great candidates for replacement of indium oxide doped with tin (ITO) in photoelectric devices. The OG was obtained from natural graphite, by Hummer's method modified, and its reduction is made by using sodium borohydride. Infrared spectroscopy analysis of Fourier transform (FTIR), Xray diffraction (XRD) and scanning electron microscopy, high-resolution (SEM/FEG) for the characterization of graphene/graphene oxide film obtained were performed. This film proved to be resilient, not dispersing in any of the various tested solvents (such as ethanol, acetone and THF), even under tip sonication, this resistance being an important property for the applications. Furthermore, the film had a morphology similar to that obtained by other preparation methods.(author)

Synthesis and electrical characterization of Graphene Oxide films

International Nuclear Information System (INIS)

Yasin, Muhammad; Tauqeer, T.; Zaidi, Syed M.H.; San, Sait E.; Mahmood, Asad; Köse, Muhammet E.; Canimkurbey, Betul; Okutan, Mustafa

2015-01-01

In this work, we have synthesized Graphene Oxide (GO) using modified Hummers method and investigated its electrical properties using parallel plate impedance spectroscopic technique. Graphene Oxide films were prepared using drop casting method on Indium Tin Oxide (ITO) coated glass substrate. Atomic force microscopy was used to characterize the films' microstructure and surface topography. Electrical characterization was carried out using LCR meter in frequency regime (100 Hz to 10 MHz) at different temperatures. AC conductivity σ ac of the films was observed to be varied with angular frequency, ω as ω S , with S < 1. The electrical properties of GO were found to be both frequency and temperature dependent. Analysis showed that GO film contains direct current (DC) and Correlated Barrier Hopping (CBH) conductivity mechanisms at low and high frequency ranges, respectively. Photon absorption and transmittance capability in the visible range and excellent electrical parameters of solution processed Graphene Oxide suggest its suitability for the realization of low cost flexible organic solar cells and organic Thin Film Transistors, respectively. - Highlights: • Synthesize and electrical characterization of Graphene Oxide (GO) Film was undertaken. • Temperature dependent impedance spectroscopy was used for electrical analysis. • AFM was used to characterize films' microstructure and surface topography. • Electrical parameters were found to vary with both temperature and frequency. • GO showed DC and CBH conductivity mechanisms at low and high frequency, respectively

Combustion synthesized indium-tin-oxide (ITO) thin film for source/drain electrodes in all solution-processed oxide thin-film transistors

International Nuclear Information System (INIS)

Tue, Phan Trong; Inoue, Satoshi; Takamura, Yuzuru; Shimoda, Tatsuya

2016-01-01

We report combustion solution synthesized (SCS) indium-tin-oxide (ITO) thin film, which is a well-known transparent conductive oxide, for source/drain (S/D) electrodes in solution-processed amorphous zirconium-indium-zinc-oxide TFT. A redox-based combustion synthetic approach is applied to ITO thin film using acetylacetone as a fuel and metal nitrate as oxidizer. The structural and electrical properties of SCS-ITO precursor solution and thin films were systematically investigated with changes in tin concentration, indium metal precursors, and annealing conditions such as temperature, time, and ambient. It was found that at optimal conditions the SCS-ITO thin film exhibited high crystalline quality, atomically smooth surface (RMS ∝ 4.1 Aa), and low electrical resistivity (4.2 x 10 -4 Ω cm). The TFT using SCS-ITO film as the S/D electrodes showed excellent electrical properties with negligible hysteresis. The obtained ''on/off'' current ratio, subthreshold swing factor, subthreshold voltage, and field-effect mobility were 5 x 10 7 , 0.43 V/decade, 0.7 V, and 2.1 cm 2 /V s, respectively. The performance and stability of the SCS-ITO TFT are comparable to those of the sputtered-ITO TFT, emphasizing that the SCS-ITO film is a promising candidate for totally solution-processed oxide TFTs. (orig.)

Synthesis and characterization of MoB2−x thin films grown by nonreactive DC magnetron sputtering

International Nuclear Information System (INIS)

Malinovskis, Paulius; Lewin, Erik; Jansson, Ulf; Palisaitis, Justinas; Persson, Per O. Å.

2016-01-01

DC magnetron sputtering was used to deposit molybdenum boride thin films for potential low-friction applications. The films exhibit a nanocomposite structure with ∼10 nm large MoB 2−x (x > 0.4) grains surrounded by a boron-rich tissue phase. The preferred formation of the metastable and substoichiometric hP3-MoB 2 structure (AlB 2 -type) is explained with kinetic constraints to form the thermodynamically stable hR18-MoB 2 phase with a very complex crystal structure. Nanoindentation revealed a relatively high hardness of (29 ± 2) GPa, which is higher than bulk samples. The high hardness can be explained by a hardening effect associated with the nanocomposite microstructure where the surrounding tissue phase restricts dislocation movement. A tribological study confirmed a significant formation of a tribofilm consisting of molybdenum oxide and boron oxide, however, without any lubricating effects at room temperature.

Thermal oxidation of Ni films for p-type thin-film transistors

KAUST Repository

Jiang, Jie; Wang, Xinghui; Zhang, Qing; Li, Jingqi; Zhang, Xixiang

2013-01-01

p-Type nanocrystal NiO-based thin-film transistors (TFTs) are fabricated by simply oxidizing thin Ni films at temperatures as low as 400 °C. The highest field-effect mobility in a linear region and the current on-off ratio are found to be 5.2 cm2 V-1 s-1 and 2.2 × 103, respectively. X-ray diffraction, transmission electron microscopy and electrical performances of the TFTs with "top contact" and "bottom contact" channels suggest that the upper parts of the Ni films are clearly oxidized. In contrast, the lower parts in contact with the gate dielectric are partially oxidized to form a quasi-discontinuous Ni layer, which does not fully shield the gate electric field, but still conduct the source and drain current. This simple method for producing p-type TFTs may be promising for the next-generation oxide-based electronic applications. © 2013 the Owner Societies.

A molybdenum disulfide/carbon nanotube heterogeneous complementary inverter.

Science.gov (United States)

Huang, Jun; Somu, Sivasubramanian; Busnaina, Ahmed

2012-08-24

We report a simple, bottom-up/top-down approach for integrating drastically different nanoscale building blocks to form a heterogeneous complementary inverter circuit based on layered molybdenum disulfide and carbon nanotube (CNT) bundles. The fabricated CNT/MoS(2) inverter is composed of n-type molybdenum disulfide (MOS(2)) and p-type CNT transistors, with a high voltage gain of 1.3. The CNT channels are fabricated using directed assembly while the layered molybdenum disulfide channels are fabricated by mechanical exfoliation. This bottom-up fabrication approach for integrating various nanoscale elements with unique characteristics provides an alternative cost-effective methodology to complementary metal-oxide-semiconductors, laying the foundation for the realization of high performance logic circuits.

Materials and Breakdown Phenomena: Heterogeneous Molybdenum Metallic Films

Directory of Open Access Journals (Sweden)

Augusto Marcelli

2017-05-01

Full Text Available Technological activities to design, manufacture, and test new accelerating devices using different materials and methods is under way all over the world. The main goal of these studies is to increase the accelerating gradients and reduce the probability of radio-frequency (RF breakdown. Indeed, it is still not clear why, by increasing the intensity of the applied field, intense surface damage is observed in copper structures, limiting the lifetime and, therefore, the practical applications. A possible solution is represented by a coating of a relatively thick layer of molybdenum in order to improve the breakdown rate. molybdenum can be reliably grown on different substrates with a negligible strain and, for thicknesses up to 600 nm, with a resistivity < 100–150·μΩ cm. Moreover, Mo coatings with controlled composition, internal stress, and roughness may allow improving thermo-mechanical properties reaching values not attainable by uncoated copper. Although the Mo conductivity remains lower compared to Cu, a Mo coating represents a very interesting option for high gradient accelerator components manufactured in copper.

Molybdenum thin film deposited by in-line DC magnetron sputtering as a back contact for Cu(In,Ga)Se{sub 2} solar cells

Energy Technology Data Exchange (ETDEWEB)

Li Zhaohui; Cho, Eou-Sik [Department of Electronics Engineering, Kyungwon University, San 65, Bokjung-dong, Soojung-gu, Seongnam city, Kyunggi-do, 461-701 (Korea, Republic of); Kwon, Sang Jik, E-mail: sjkwon@kyungwon.ac.kr [Department of Electronics Engineering, Kyungwon University, San 65, Bokjung-dong, Soojung-gu, Seongnam city, Kyunggi-do, 461-701 (Korea, Republic of)

2011-09-01

In this paper, we reported the effect of the power and the working pressure on the molybdenum (Mo) films deposited using an in-line direct current (DC) magnetron sputtering system. The electrical and the structural properties of Mo film were improved by increasing DC power from 1 to 3 kW. On the other side, the resistivity of the Mo films became higher with the increasing working pressure. However, the adhesion property was improved when the working pressure was higher. In this work, in order to obtain an optimal Mo film as a back metal contact of Cu(In,Ga)Se{sub 2} (CIGS) solar cells, a bilayer Mo film was formed through the different film structures depending on the working pressure. The first layer was formed at a high pressure of 12 mTorr for a better adhesion and the second layer was formed at a low pressure of 3 mTorr for a lower resistivity.

Mn-implanted, polycrystalline indium tin oxide and indium oxide films

International Nuclear Information System (INIS)

Scarlat, Camelia; Vinnichenko, Mykola; Xu Qingyu; Buerger, Danilo; Zhou Shengqiang; Kolitsch, Andreas; Grenzer, Joerg; Helm, Manfred; Schmidt, Heidemarie

2009-01-01

Polycrystalline conducting, ca. 250 nm thick indium tin oxide (ITO) and indium oxide (IO) films grown on SiO 2 /Si substrates using reactive magnetron sputtering, have been implanted with 1 and 5 at.% of Mn, followed by annealing in nitrogen or in vacuum. The effect of the post-growth treatment on the structural, electrical, magnetic, and optical properties has been studied. The roughness of implanted films ranges between 3 and 15 nm and XRD measurements revealed a polycrystalline structure. A positive MR has been observed for Mn-implanted and post-annealed ITO and IO films. It has been interpreted by considering s-d exchange. Spectroscopic ellipsometry has been used to prove the existence of midgap electronic states in the Mn-implanted ITO and IO films reducing the transmittance below 80%.

Nuclear microanalysis of oxide films on structural steel

International Nuclear Information System (INIS)

Istomin, I.V.; Karabash, V.A.; Maisyukov, V.D.; Sosnin, A.N.; Shorin, V.S.

1989-01-01

Studies of the behavior of structural materials in nuclear power plants have indicated the important role of oxide films on metals, especially metals of the iron group. The films may be formed as a result of the corrosion of the metal in an aggressive coolant. At the same time, some oxide films have anticorrosive properties and can be produced specially by the introduction of inhibitor-passivators, e.g., molecular oxygen, into the aggressive medium. Experimental data on the film growth rate make it possible to determine the kinetics of the oxidation process, the nature of the diffusion of the main components through the film, and the role of the phase transitions (crystal-chemical transformations) and point defects during the migration of oxygen and metal ions through the oxide. In this study nuclear microanalysis is used to measure the parameters of oxide films formed on 10Cr2Mo and 1Cr18Ni10Ti steels in steam in the temperature range 320-620C. In this method the film parameters in the general analysis of the energy spectra of deuterons back-scattered from iron nuclei and protons in the case of the 16 O(d,p 1 ) 17 O nuclear reaction. With this approach and an initial deuteron energy E o = 0.9 MeV the range of the measurable thickness t of the films is 0.001-1.5 mg/cm 2 . The data obtained not only confirm the high sensitivity of the nuclear microanalysis method but also demonstrate that it can be used for nondestructive quality control of the surface

Films based on oxidized starch and cellulose from barley.

Science.gov (United States)

El Halal, Shanise Lisie Mello; Colussi, Rosana; Deon, Vinícius Gonçalves; Pinto, Vânia Zanella; Villanova, Franciene Almeida; Carreño, Neftali Lenin Villarreal; Dias, Alvaro Renato Guerra; Zavareze, Elessandra da Rosa

2015-11-20

Starch and cellulose fibers were isolated from grains and the husk from barley, respectively. Biodegradable films of native starch or oxidized starches and glycerol with different concentrations of cellulose fibers (0%, 10% and 20%) were prepared. The films were characterized by morphological, mechanical, barrier, and thermal properties. Cellulose fibers isolated from the barley husk were obtained with 75% purity and high crystallinity. The morphology of the films of the oxidized starches, regardless of the fiber addition, was more homogeneous as compared to the film of the native starch. The addition of cellulose fibers in the films increased the tensile strength and decreased elongation. The water vapor permeability of the film of oxidized starch with 20% of cellulose fibers was lower than the without fibers. However the films with cellulose fibers had the highest decomposition with the initial temperature and thermal stability. The oxidized starch and cellulose fibers from barley have a good potential for use in packaging. The addition of cellulose fibers in starch films can contribute to the development of films more resistant that can be applied in food systems to maintain its integrity. Copyright © 2015 Elsevier Ltd. All rights reserved.

Monodispersed macroporous architecture of nickel-oxide film as an anode material for thin-film lithium-ion batteries

International Nuclear Information System (INIS)

Wu, Mao-Sung; Lin, Ya-Ping

2011-01-01

A nickel-oxide film with monodispersed open macropores was prepared on a stainless-steel substrate by electrophoretic deposition of a polystyrene-sphere monolayer followed by anodic electrodeposition of nickel oxy-hydroxide. The deposited films convert to cubic nickel oxide after annealing at 400 o C for 1 h. Galvanostatic charge and discharge results indicate that the nickel-oxide film with monodispersed open macropores is capable of delivering a higher capacity than the bare nickel-oxide film, especially in high-rate charge and discharge processes. The lithiation capacity of macroporous nickel oxide reaches 1620 mA h g -1 at 1 C current discharge and decreases to 990 mA h g -1 at 15 C current discharge. The presence of monodispersed open macropores in the nickel-oxide film might facilitate the electrolyte penetration, diffusion, and migration. Electrochemical reactions between nickel oxide and lithium ions are therefore markedly improved by this tailored film architecture.

Bismuth iron oxide thin films using atomic layer deposition of alternating bismuth oxide and iron oxide layers

Energy Technology Data Exchange (ETDEWEB)

Puttaswamy, Manjunath; Vehkamäki, Marko [University of Helsinki, Department of Chemistry, P.O. Box 55, FI-00014 Helsinki (Finland); Kukli, Kaupo, E-mail: kaupo.kukli@helsinki.fi [University of Helsinki, Department of Chemistry, P.O. Box 55, FI-00014 Helsinki (Finland); University of Tartu, Institute of Physics, W. Ostwald 1, EE-50411 Tartu (Estonia); Dimri, Mukesh Chandra [National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, EE-12618 Tallinn (Estonia); Kemell, Marianna; Hatanpää, Timo; Heikkilä, Mikko J. [University of Helsinki, Department of Chemistry, P.O. Box 55, FI-00014 Helsinki (Finland); Mizohata, Kenichiro [University of Helsinki, Department of Physics, P.O. Box 64, FI-00014 Helsinki (Finland); Stern, Raivo [National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, EE-12618 Tallinn (Estonia); Ritala, Mikko; Leskelä, Markku [University of Helsinki, Department of Chemistry, P.O. Box 55, FI-00014 Helsinki (Finland)

2016-07-29

Bismuth iron oxide films with varying contributions from Fe{sub 2}O{sub 3} or Bi{sub 2}O{sub 3} were prepared using atomic layer deposition. Bismuth (III) 2,3-dimethyl-2-butoxide, was used as the bismuth source, iron(III) tert-butoxide as the iron source and water vapor as the oxygen source. The films were deposited as stacks of alternate Bi{sub 2}O{sub 3} and Fe{sub 2}O{sub 3} layers. Films grown at 140 °C to the thickness of 200–220 nm were amorphous, but crystallized upon post-deposition annealing at 500 °C in nitrogen. Annealing of films with intermittent bismuth and iron oxide layers grown to different thicknesses influenced their surface morphology, crystal structure, composition, electrical and magnetic properties. Implications of multiferroic performance were recognized in the films with the remanent charge polarization varying from 1 to 5 μC/cm{sup 2} and magnetic coercivity varying from a few up to 8000 A/m. - Highlights: • Bismuth iron oxide thin films were grown by atomic layer deposition at 140 °C. • The major phase formed in the films upon annealing at 500 °C was BiFeO{sub 3}. • BiFeO{sub 3} films and films containing excess Bi favored electrical charge polarization. • Slight excess of iron oxide enhanced saturative magnetization behavior.

Synthesis and characterization of MoB{sub 2−x} thin films grown by nonreactive DC magnetron sputtering

Energy Technology Data Exchange (ETDEWEB)

Malinovskis, Paulius, E-mail: paulius.malinovskis@kemi.uu.se; Lewin, Erik; Jansson, Ulf [Department of Chemistry–Ångström Laboratory, Uppsala University, SE-751 21 Uppsala (Sweden); Palisaitis, Justinas; Persson, Per O. Å. [Department of Physics, Chemistry, and Biology (IFM), Thin Film Physics Division, Linköping University, SE-581 83 Linköping (Sweden)

2016-05-15

DC magnetron sputtering was used to deposit molybdenum boride thin films for potential low-friction applications. The films exhibit a nanocomposite structure with ∼10 nm large MoB{sub 2−x} (x > 0.4) grains surrounded by a boron-rich tissue phase. The preferred formation of the metastable and substoichiometric hP3-MoB{sub 2} structure (AlB{sub 2}-type) is explained with kinetic constraints to form the thermodynamically stable hR18-MoB{sub 2} phase with a very complex crystal structure. Nanoindentation revealed a relatively high hardness of (29 ± 2) GPa, which is higher than bulk samples. The high hardness can be explained by a hardening effect associated with the nanocomposite microstructure where the surrounding tissue phase restricts dislocation movement. A tribological study confirmed a significant formation of a tribofilm consisting of molybdenum oxide and boron oxide, however, without any lubricating effects at room temperature.

Magnetic properties of sputtered Permalloy/molybdenum multilayers

International Nuclear Information System (INIS)

Romera, M.; Ciudad, D.; Maicas, M.; Aroca, C.; Ranchal, R.

2011-01-01

In this work, we report the magnetic properties of sputtered Permalloy (Py: Ni 80 Fe 20 )/molybdenum (Mo) multilayer thin films. We show that it is possible to maintain a low coercivity and a high permeability in thick sputtered Py films when reducing the out-of-plane component of the anisotropy by inserting thin film spacers of a non-magnetic material like Mo. For these kind of multilayers, we have found coercivities which are close to those for single layer films with no out-of-plane anisotropy. The coercivity is also dependent on the number of layers exhibiting a minimum value when each single Py layer has a thickness close to the transition thickness between Neel and Bloch domain walls.

Performance and impedance studies of thin, porous molybdenum and tungsten electrodes for the alkali metal thermoelectric converter

Science.gov (United States)

Wheeler, B. L.; Williams, R. M.; Jeffries-Nakamura, B.; Lamb, J. L.; Loveland, M. E.; Bankston, C. P.; Cole, T.

1988-01-01

Columnar, porous, magnetron-sputtered molybdenum and tungsten films show optimum performance as alkali metal thermoelectric converter electrodes at thicknesses less than 1.0 micron when used with molybdenum or nickel current collector grids. Power densities of 0.40 W/sq cm for 0.5-micron molybdenum films at 1200 K and 0.35 W/sq cm for 0.5-micron tungsten films at 1180 K were obtained at electrode maturity after 40-90 h. Sheet resistances of magnetron sputter deposited films on sodium beta-double-prime-alumina solid electrolyte (BASE) substrates were found to increase very steeply as thickness is decreased below about 0.3-double-prime 0.4-micron. The ac impedance data for these electrodes have been interpreted in terms of contributions from the bulk BASE and the porous electrode/BASE interface. Voltage profiles of operating electrodes show that the total electrode area, of electrodes with thickness less than 2.0 microns, is not utilized efficiently unless a fairly fine (about 1 x 1 mm) current collector grid is employed.

In Situ and Ex Situ Studies of Molybdenum Thin Films Deposited by rf and dc Magnetron Sputtering as a Back Contact for CIGS Solar Cells

Directory of Open Access Journals (Sweden)

K. Aryal

2012-01-01

Full Text Available Molybdenum thin films were deposited by rf and dc magnetron sputtering and their properties analyzed with regards to their potential application as a back contact for CIGS solar cells. It is shown that both types of films tend to transition from tensile to compressive strain when the deposition pressure increases, while the conductivity and the grain size decreas. The nucleation of the films characterized by in situ and real time spectroscopic ellipsometry shows that both films follow a Volmer-Weber growth, with a higher surface roughness and lower deposition rate for the rf deposited films. The electronic relaxation time was then extracted as a function of bulk layer thickness for rf and dc films by fitting each dielectric function to a Drude free-electron model combined with a broad Lorentz oscillator. The values were fitted to a conical growth mode and demonstrated that the rf-deposited films have already smaller grains than the dc films when the bulk layer thickness is 30 nm.

Photoconductivity of oxidized nanostructured PbTe(In) films

International Nuclear Information System (INIS)

Dobrovolsky, A A; Ryabova, L I; Khokhlov, D R; Dashevsky, Z M; Kasiyan, V A

2009-01-01

Photoconductivity of as-grown and oxidized nanocrystalline PbTe(In) films has been studied in the dc and ac modes at temperatures 4.2–300 K. The electric transport in the films is defined by two mechanisms: conductivity through barriers at grain boundaries and transport along inversion channels at the grain surface. Modification of the transport mechanisms induced by oxidation is considered. Relatively weak oxidation results in an increase in the contribution of grain barriers to conductivity followed by an enhancement of the photoconductivity amplitude. Instead, this contribution drops in the case of deep oxidation resulting in a photoresponse reduction. It is shown that the main mechanism of charge transport in deeply oxidized films at low temperatures is hopping along inversion channels at the grain surface. It is demonstrated that the photoconductive response of nanocrystalline materials may be optimized by variation of the oxidation level, measurement frequency and temperature

Plasmachemical synthesis and evaluation of the thermal conductivity of metal-oxide compounds "Molybdenum-uranium dioxide"

Science.gov (United States)

Kotelnikova, Alexandra A.; Karengin, Alexander G.; Mendoza, Orlando

2018-03-01

The article represents possibility to apply oxidative and reducing plasma for plasma-chemical synthesis of metal-oxide compounds «Mo‒UO2» from water-salt mixtures «molybdic acid‒uranyl nitrate» and «molybdic acid‒ uranyl acetate». The composition of water-salt mixture was calculated and the conditions ensuring plasma-chemical synthesis of «Mo‒UO2» compounds were determined. Calculations were carried out at atmospheric pressure over a wide range of temperatures (300-4000 K), with the use of various plasma coolants (air, hydrogen). The heat conductivity coefficients of metal-oxide compounds «Mo‒UO2» consisting of continuous component (molybdenum matrix) are calculated. Inclusions from ceramics in the form of uranium dioxide were ordered in the matrix. Particular attention is paid to methods for calculating the coefficients of thermal conductivity of these compounds with the use of different models. Calculated results were compared with the experimental data.

Chemically abrupt interface between Ce oxide and Fe films

International Nuclear Information System (INIS)

Lee, H.G.; Lee, D.; Kim, S.; Kim, S.G.; Hwang, Chanyong

2005-01-01

A chemically abrupt Fe/Ce oxide interface can be formed by initial oxidation of an Fe film followed by deposition of Ce metal. Once a Ce oxide layer is formed on top of Fe, it acts a passivation barrier for oxygen diffusion. Further deposition of Ce metal followed by its oxidation preserve the abrupt interface between Ce oxide and Fe films. The Fe and Ce oxidation states have been monitored at each stage using X-ray photoelectron spectroscopy

Degradation of superconducting Nb/NbN films by atmospheric oxidation

Energy Technology Data Exchange (ETDEWEB)

Henry, Michael David; Wolfley, Steven L.; Young, Travis Ryan; Monson, Todd; Pearce, Charles Joseph; Lewis, Rupert M.; Clark, Blythe; Brunke, Lyle Brent; Missert, Nancy A.

2017-03-01

Niobium and niobium nitride thin films are transitioning from fundamental research toward wafer scale manufacturing with technology drivers that include superconducting circuits and electronics, optical single photon detectors, logic, and memory. Successful microfabrication requires precise control over the properties of sputtered superconducting films, including oxidation. Previous work has demonstrated the mechanism in oxidation of Nb and how film structure could have deleterious effects upon the superconducting properties. This study provides an examination of atmospheric oxidation of NbN films. By examination of the room temperature sheet resistance of NbN bulk oxidation was identified and confirmed by secondary ion mass spectrometry. As a result, Meissner magnetic measurements confirmed the bulk oxidation not observed with simple cryogenic resistivity measurements.

Surface morphology study on chromium oxide growth on Cr films by Nd-YAG laser oxidation process

International Nuclear Information System (INIS)

Dong Qizhi; Hu Jiandong; Guo Zuoxing; Lian Jianshe; Chen Jiwei; Chen Bo

2002-01-01

Grain sized (60-100 nm) Cr 2 O 3 thin films were prepared on Cr thin film surfaces by Nd-YAG laser photothermal oxidation process. Surface morphology study showed crack-free short plateau-like oxide films formed. Increase of dislocation density after pulsed laser irradiation was found. Thin film external surfaces, grain boundaries and dislocations are main paths of laser surface oxidation. Pinning and sealing of grain boundary was the reason that deeper oxidation did not produce. Grain growth and agglomeration of Cr sub-layer yielded tensile stress on the surface Cr 2 O 3 thin film. It was the reason that short plateau-like surface morphology formed and cracks appeared sometimes. In oxygen annealing at 700 deg. C, grain boundaries were considered not to be pinned at the surface, mixture diffusion was main mechanism in growth of oxide. Compression stress development in whole film led to extrusion of grains that was the reason that multiple appearances such as pyramid-like and nutshell-like morphology formed

High heat flux testing of TiC coated molybdenum with a tungsten intermediate layer

International Nuclear Information System (INIS)

Fujitsuka, Masakazu; Fukutomi, Masao; Okada, Masatoshi

1988-01-01

The use of low atomic number (Z) material coatings for fusion reactor first-wall components has proved to be a valuable technique to reduce the plasma radiation losses. Molybdenum coated with titanium carbide is considered very promising since it has a good capability of receiving heat from the plasma. An interfacial reaction between the TiC film and the molybdenum substrate, however, causes a severe deterioration of the film at elevated temperatures. In order to solve this problem a TiC coated molybdenum with an intermediate tungsten layer was developed. High temperature properties of this material was evaluated by a newly devised electron beam heating apparatus. TiC coatings prepared on a vacuum-heat-treated molybdenum with a tungsten intermediate layer showed good high temperature stability and survived 2.0 s pulses of heating at a power density as high as 53 MW/m 2 . The melt area of the TiC coatings in high heat flux testings also markedly decreased when a tungsten intermediate layer was applied. The melting mechanism of the TiC coatings with and without a tungsten intermediate layer was discussed by EPMA measurements. (author)

Uranium and Molybdenum extraction from a Cerro Solo deposit ore

International Nuclear Information System (INIS)

Becquart, Elena T.; Arias, Maria J.; Fuente, Juan C. de la; Misischia, Yamila A.; Santa Cruz, Daniel E.; Tomellini, Guido C.

2009-01-01

Cerro Solo, located in Chubut, Argentina, is a sandstone type uranium-molybdenum deposit. Good recovery of both elements can be achieved by acid leaching of the ore but the presence of molybdenum in pregnant liquors is an inconvenient to uranium separation and purification. A two steps process is developed. A selective alkaline leaching of the ore with sodium hydroxide allows separating and recovering of molybdenum and after solid-liquid separation, the ore is acid leached to recover uranium. Several samples averaging 0,2% uranium and 0,1% molybdenum with variable U/Mo ratio have been used and in both steps, leaching and oxidant reagents concentration, temperature and residence time in a stirred tank leaching have been studied. In alkaline leaching molybdenum recoveries greater than 96% are achieved, with 1% uranium extraction. In acid leaching up to 93% of the uranium is extracted and Mo/U ratio in solvent extraction feed is between 0,013 and 0,025. (author)

Raman and XPS characterization of vanadium oxide thin films with temperature

Energy Technology Data Exchange (ETDEWEB)

Ureña-Begara, Ferran, E-mail: ferran.urena@uclouvain.be [Université catholique de Louvain, Institute of Information and Communication Technologies, Electronics and Applied Mathematics (ICTEAM), Louvain-la-Neuve (Belgium); Crunteanu, Aurelian [XLIM Research Institute, UMR 7252, CNRS/Université de Limoges, Limoges (France); Raskin, Jean-Pierre [Université catholique de Louvain, Institute of Information and Communication Technologies, Electronics and Applied Mathematics (ICTEAM), Louvain-la-Neuve (Belgium)

2017-05-01

Highlights: • Comprehensive study of the oxidation of VO{sub 2} thin films from R.T. up to 550 °C. • Phase changes and mixed-valence vanadium oxides formed during the oxidation process. • Reported Raman and XPS signatures for each vanadium oxide. • Monitoring of the current and resistance evolution at the surface of the films. • Oxidation model describing the evolution of the vanadium oxides and phase changes. - Abstract: The oxidation mechanisms and the numerous phase transitions undergone by VO{sub 2} thin films deposited on SiO{sub 2}/Si and Al{sub 2}O{sub 3} substrates when heated from room temperature (R.T.) up to 550 °C in air are investigated by Raman and X-ray photoelectron spectroscopy. The results show that the films undergo several intermediate phase transitions between the initial VO{sub 2} monoclinic phase at R.T. and the final V{sub 2}O{sub 5} phase at 550 °C. The information about these intermediate phase transitions is scarce and their identification is important since they are often found during the synthesis of vanadium dioxide films. Significant changes in the film conductivity have also been observed to occur associated to the phase transitions. In this work, current and resistance measurements performed on the surface of the films are implemented in parallel with the Raman measurements to correlate the different phases with the conductivity of the films. A model to explain the oxidation mechanisms and phenomena occurring during the oxidation of the films is proposed. Peak frequencies, full-width half-maxima, binding energies and oxidation states from the Raman and X-ray photoelectron spectroscopy experiments are reported and analyzed for all the phases encountered in VO{sub 2} films prepared on SiO{sub 2}/Si and Al{sub 2}O{sub 3} substrates.

Water clustering on nanostructured iron oxide films

DEFF Research Database (Denmark)

Merte, Lindsay Richard; Bechstein, Ralf; Peng, G.

2014-01-01

, but it is not well-understood how these hydroxyl groups and their distribution on a surface affect the molecular-scale structure at the interface. Here we report a study of water clustering on a moire-structured iron oxide thin film with a controlled density of hydroxyl groups. While large amorphous monolayer...... islands form on the bare film, the hydroxylated iron oxide film acts as a hydrophilic nanotemplate, causing the formation of a regular array of ice-like hexameric nanoclusters. The formation of this ordered phase is localized at the nanometre scale; with increasing water coverage, ordered and amorphous...

X-ray target with substrate of molybdenum alloy

International Nuclear Information System (INIS)

Hirsch, H.H.

1980-01-01

Rotary targets for x-ray tubes are provided comprising a molybdenum base body alloyed with a stabilizing proportion of iron, silicon, cobalt, tantalum, niobium, hafnium, stable metal oxide, or a mixture of the preceding

Strengthening and elongation mechanism of Lanthanum-doped Titanium-Zirconium-Molybdenum alloy

Energy Technology Data Exchange (ETDEWEB)

Hu, Ping, E-mail: huping1985@126.com [School of Metallurgy Engineering, Xi’an University of Architecture and Technology, Xi’an 710055 (China); Jinduicheng Molybdenum Co., Ltd., Xi’an 710068 (China); Hu, Bo-liang; Wang, Kuai-she; Song, Rui; Yang, Fan [School of Metallurgy Engineering, Xi’an University of Architecture and Technology, Xi’an 710055 (China); Yu, Zhi-tao [Ruifulai Tungsten & Molybdenum Co., Ltd., Xi’an 721914 (China); Tan, Jiang-fei [School of Metallurgy Engineering, Xi’an University of Architecture and Technology, Xi’an 710055 (China); Cao, Wei-cheng; Liu, Dong-xin; An, Geng [Jinduicheng Molybdenum Co., Ltd., Xi’an 710068 (China); Guo, Lei [Ruifulai Tungsten & Molybdenum Co., Ltd., Xi’an 721914 (China); Yu, Hai-liang [School of Mechanical, Materials and Mechatronics Engineering, University of Wollongong, NSW 2522 (Australia)

2016-12-15

The microstructural contributes to understand the strengthening and elongation mechanism in Lanthanum-doped Titanium-Zirconium-Molybdenum alloy. Lanthanum oxide particles not only act as heterogeneous nucleation core, but also act as the second phase to hinder the grain growth during sintering crystallization. The molybdenum substrate formed sub-grain under the effect of second phase when the alloy rolled to plate.

Thick-film effects in the oxidation and hydriding of zirconium alloys

International Nuclear Information System (INIS)

Johnson, A.B. Jr.

1989-08-01

One of the fundamental discoveries involving radiation effects on the oxidation of Zircaloy in low-oxygen aqueous environments is the influence of thick oxide films. Zircaloy oxidation rates in low-oxygen (hydrogen-rich) coolants initially proceed at relatively low rates, often almost uninfluenced by radiation. Marked upturns in oxidation rate have signaled the onset of radiation effects. The radiation effects appear to correlate with a threshold oxide thickness. Results of the test reactor experiments lead to formulation of the Thick-Film Hypothesis: beyond a threshold oxide thickness, radiolysis of water that infiltrates oxide cracks and pores controls the oxidation rate; radiation creates microenvironments inside the oxide film, producing highly oxidizing conditions, that are no longer suppressed by the coolant-borne hydrogen. Upturns in oxidation rate on high-exposure Zircaloy pressure tubes add confirmatory evidence for the thick-film effect. This paper summarizes the early evidence for thick-film behavior, including oxidation and hydriding trends, updates confirmatory evidence from Zircaloy reactor and fuel assembly components, and highlights other observations from the test reactor series that have potential fundamental significance to explanations of radiation effects on Zircaloy. 23 refs., 10 figs

Atomic layer deposition of calcium oxide and calcium hafnium oxide films using calcium cyclopentadienyl precursor

International Nuclear Information System (INIS)

Kukli, Kaupo; Ritala, Mikko; Sajavaara, Timo; Haenninen, Timo; Leskelae, Markku

2006-01-01

Calcium oxide and calcium hafnium oxide thin films were grown by atomic layer deposition on borosilicate glass and silicon substrates in the temperature range of 205-300 o C. The calcium oxide films were grown from novel calcium cyclopentadienyl precursor and water. Calcium oxide films possessed refractive index 1.75-1.80. Calcium oxide films grown without Al 2 O 3 capping layer occurred hygroscopic and converted to Ca(OH) 2 after exposure to air. As-deposited CaO films were (200)-oriented. CaO covered with Al 2 O 3 capping layers contained relatively low amounts of hydrogen and re-oriented into (111) direction upon annealing at 900 o C. In order to examine the application of CaO in high-permittivity dielectric layers, mixtures of Ca and Hf oxides were grown by alternate CaO and HfO 2 growth cycles at 230 and 300 o C. HfCl 4 was used as a hafnium precursor. When grown at 230 o C, the films were amorphous with equal amounts of Ca and Hf constituents (15 at.%). These films crystallized upon annealing at 750 o C, showing X-ray diffraction peaks characteristic of hafnium-rich phases such as Ca 2 Hf 7 O 16 or Ca 6 Hf 19 O 44 . At 300 o C, the relative Ca content remained below 8 at.%. The crystallized phase well matched with rhombohedral Ca 2 Hf 7 O 16 . The dielectric films grown on Si(100) substrates possessed effective permittivity values in the range of 12.8-14.2

Ternary cobalt-molybdenum-zirconium coatings for alternative energies

Science.gov (United States)

Yar-Mukhamedova, Gulmira; Ved', Maryna; Sakhnenko, Nikolay; Koziar, Maryna

2017-11-01

Consistent patterns for electrodeposition of Co-Mo-Zr coatings from polyligand citrate-pyrophosphate bath were investigated. The effect of both current density amplitude and pulse on/off time on the quality, composition and surface morphology of the galvanic alloys were determined. It was established the coating Co-Mo-Zr enrichment by molybdenum with current density increasing up to 8 A dm-2 as well as the rising of pulse time and pause duration promotes the content of molybdenum because of subsequent chemical reduction of its intermediate oxides by hydrogen ad-atoms. It was found that the content of the alloying metals in the coating Co-Mo-Zr depends on the current density and on/off times extremely and maximum Mo and Zr content corresponds to the current density interval 4-6 A dm-2, on-/off-time 2-10 ms. Chemical resistance of binary and ternary coatings based on cobalt is caused by the increased tendency to passivity and high resistance to pitting corrosion in the presence of molybdenum and zirconium, as well as the acid nature of their oxides. Binary coating with molybdenum content not less than 20 at.% and ternary ones with zirconium content in terms of corrosion deep index are in a group ;very proof;. It was shown that Co-Mo-Zr alloys exhibits the greatest level of catalytic properties as cathode material for hydrogen electrolytic production from acidic media which is not inferior a platinum electrode. The deposits Co-Mo-Zr with zirconium content 2-4 at.% demonstrate high catalytic properties in the carbon(II) oxide conversion. This confirms the efficiency of materials as catalysts for the gaseous wastes purification and gives the reason to recommend them as catalysts for red-ox processes activating by oxygen as well as electrode materials for red-ox batteries.

Predicting molybdenum toxicity to higher plants: Influence of soil properties

International Nuclear Information System (INIS)

McGrath, S.P.; Mico, C.; Curdy, R.; Zhao, F.J.

2010-01-01

The effect of soil properties on the toxicity of molybdenum (Mo) to four plant species was investigated. Soil organic carbon or ammonium-oxalate extractable Fe oxides were found to be the best predictors of the 50% effective dose (ED 50 ) of Mo in different soils, explaining > 65% of the variance in ED 50 for four species except for ryegrass (26-38%). Molybdenum concentrations in soil solution and consequently plant uptake were increased when soil pH was artificially raised because sorption of Mo to amorphous oxides is greatly reduced at high pH. The addition of sulphate significantly decreased Mo uptake by oilseed rape. For risk assessment, we suggest that Mo toxicity values for plants should be normalised using soil amorphous iron oxide concentrations. - Amorphous iron oxides or organic carbon were found to be the best predictors of the toxicity threshold values of Mo to higher plants on different soils.

Sputtered indium oxide films

International Nuclear Information System (INIS)

Gillery, F.H.

1986-01-01

A method is described for depositing on a substrate multiple layer films comprising at least one primary layer of a metal oxide and at least one primary layer of a metal other than the metal of the oxide layer. The improvement described here comprises improving the adhesion between the metal oxide and metal layers by depositing between the layers an intermediate metal-containing layer having an affinity for both the metal and metal oxide layers. An article of manufacture is described comprising a nonmetallic substrate, and deposited thereon in any order: a. at least one coating layer of metal; b. at least one coating layer of an oxide of a metal other than the metal of the metal layer; and c. deposited between the metal and metal oxide layers an intermediate metal-containing layer having an affinity for both the metal and metal oxide layers

Oxide film assisted dopant diffusion in silicon carbide

Energy Technology Data Exchange (ETDEWEB)

Tin, Chin-Che, E-mail: cctin@physics.auburn.ed [Department of Physics, Auburn University, Alabama 36849 (United States); Mendis, Suwan [Department of Physics, Auburn University, Alabama 36849 (United States); Chew, Kerlit [Department of Electrical and Electronic Engineering, Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Kuala Lumpur (Malaysia); Atabaev, Ilkham; Saliev, Tojiddin; Bakhranov, Erkin [Physical Technical Institute, Uzbek Academy of Sciences, 700084 Tashkent (Uzbekistan); Atabaev, Bakhtiyar [Institute of Electronics, Uzbek Academy of Sciences, 700125 Tashkent (Uzbekistan); Adedeji, Victor [Department of Chemistry, Geology and Physics, Elizabeth City State University, North Carolina 27909 (United States); Rusli [School of Electrical and Electronic Engineering, Nanyang Technological University (Singapore)

2010-10-01

A process is described to enhance the diffusion rate of impurities in silicon carbide so that doping by thermal diffusion can be done at lower temperatures. This process involves depositing a thin film consisting of an oxide of the impurity followed by annealing in an oxidizing ambient. The process uses the lower formation energy of silicon dioxide relative to that of the impurity-oxide to create vacancies in silicon carbide and to promote dissociation of the impurity-oxide. The impurity atoms then diffuse from the thin film into the near-surface region of silicon carbide.

Oxide film assisted dopant diffusion in silicon carbide

International Nuclear Information System (INIS)

Tin, Chin-Che; Mendis, Suwan; Chew, Kerlit; Atabaev, Ilkham; Saliev, Tojiddin; Bakhranov, Erkin; Atabaev, Bakhtiyar; Adedeji, Victor; Rusli

2010-01-01

A process is described to enhance the diffusion rate of impurities in silicon carbide so that doping by thermal diffusion can be done at lower temperatures. This process involves depositing a thin film consisting of an oxide of the impurity followed by annealing in an oxidizing ambient. The process uses the lower formation energy of silicon dioxide relative to that of the impurity-oxide to create vacancies in silicon carbide and to promote dissociation of the impurity-oxide. The impurity atoms then diffuse from the thin film into the near-surface region of silicon carbide.

Lithium insertion in sputtered vanadium oxide film

DEFF Research Database (Denmark)

West, K.; Zachau-Christiansen, B.; Skaarup, S.V.

1992-01-01

were oxygen deficient compared to V2O5. Films prepared in pure argon were reduced to V(4) or lower. The vanadium oxide films were tested in solid-state lithium cells. Films sputtered in oxygen showed electrochemical properties similar to crystalline V2O5. The main differences are a decreased capacity...

Spark counting technique with an aluminium oxide film

International Nuclear Information System (INIS)

Kawai, H.; Koga, T.; Morishima, H.; Niwa, T.; Nishiwaki, Y.

1980-01-01

Automatic spark counting of etch-pits on a polycarbonate film produced by nuclear fission fragments is now used for neutron monitoring in several countries. A method was developed using an aluminium oxide film instead of a polycarbonate as the neutron detector. Aluminium oxide films were prepared as follows: A cleaned aluminium plate as an anode and a nickel plate as a cathode were immersed in dilute sulfuric acid solution and electric current flowed between the electrodes at 12degC for 10-30 minutes. Electric current density was about 10 mA/cm 2 . The aluminium plate was then kept in boiling water for 10-30 minutes for sealing. The thickness of the aluminium oxide layer formed was about 1μm. The aluminium plate attached to a plate of suitable fissionable material, such as uranium or thorium, was irradiated with neutrons and set in a usual spark counter for fission track counting. One electrode was the aluminium plate and the other was an aluminized polyester sheet. Sparked pulses were counted with a usual scaler. The advantage of using spark counting with an aluminium oxide film for neutron monitoring is rapid measurement of neutron exposure, since chemical etching which is indispensable for spark counting with a polycarbonate detector film, is not needed. (H.K.)

Electro-mechanical coupling of semiconductor film grown on stainless steel by oxidation

Science.gov (United States)

Lin, M. C.; Wang, G.; Guo, L. Q.; Qiao, L. J.; Volinsky, Alex A.

2013-09-01

Electro-mechanical coupling phenomenon in oxidation film on stainless steel has been discovered by using current-sensing atomic force microscopy, along with the I-V curves measurements. The oxidation films exhibit either ohmic, n-type, or p-type semiconductor properties, according to the obtained I-V curves. This technique allows characterizing oxidation films with high spatial resolution. Semiconductor properties of oxidation films must be considered as additional stress corrosion cracking mechanisms.

Oxidation of methyl heterocyclic compounds on vanadium oxide catalysts

International Nuclear Information System (INIS)

Shimanskaya, M.V.; Lejtis, L.A.; Iovel', I.G.; Gol'dberg, Yu.Sh.; Skolmejstere, R.A.; Golender, L.O.

1985-01-01

Data on vapor-phase oxidation of methyl derivatives of thiophene, Δ 2 - thiazo line, pyridine, pyrazine and pyramidine on oxide vanadium-molybdenum catalysts to corresponding heterylaldehydes are generalized. The dependence of catalytic properties of oxide vanadium-molybdenum systems in oxidation reactions of methylheterocyclic compounds on V:Mo ratio in the catalyst is revealed. It is shown that heterocyclic compounds are coordinated by a heteroatom on Lewis centres of V-Mo-O-catalyst primarily with partially reduced vanadium ions

Synthesis and luminescent properties of PEO/lanthanide oxide nanoparticle hybrid films

International Nuclear Information System (INIS)

Goubard, F.; Vidal, F.; Bazzi, R.; Tillement, O.; Chevrot, C.; Teyssie, D.

2007-01-01

In this study, we investigate the optical properties of lanthanide oxide nanoparticles dispersed in poly(ethylene oxide) (PEO) network as thermally stable polymeric films. The aim of this work is both to keep a good optical transparency in the visible domain and to obtain luminescent materials after incorporation of nanoparticles. For this purpose, we develop luminescent nanocrystals of oxides containing terbium ion as a doping element in Gd 2 O 3 . These sub-5-nm lanthanide oxides nanoparticles have been prepared by direct oxide precipitation in high-boiling polyalcohol solutions and characterized by luminescence spectroscopy. PEO/lanthanide oxide nanohybrid films are prepared by radical polymerization of poly(ethylene glycol) methacrylate after introduction of lanthanide oxide particles. As a first result; the obtained films present interesting luminescence properties with a very low lanthanide oxide content (up to 0.29 wt%). Furthermore, these films are still transparent and keep their original mechanical properties. Prior to describe the specific applications to optical use, we report here the dynamic mechanical analysis (DMA), X-ray diffraction (XRD) analysis, transmission electron microscopy (TEM), and luminescent properties of. nanohybrid films

Surface and sub-surface thermal oxidation of thin ruthenium films

NARCIS (Netherlands)

Coloma Ribera, R.; van de Kruijs, Robbert Wilhelmus Elisabeth; Kokke, S.; Zoethout, E.; Yakshin, Andrey; Bijkerk, Frederik

2014-01-01

A mixed 2D (film) and 3D (nano-column) growth of ruthenium oxide has been experimentally observed for thermally oxidized polycrystalline ruthenium thin films. Furthermore, in situ x-ray reflectivity upon annealing allowed the detection of 2D film growth as two separate layers consisting of low

Electrochemical characterization of oxide film formed at high temperature on Alloy 690

Energy Technology Data Exchange (ETDEWEB)

Abraham, Geogy J., E-mail: gja@barc.gov.in [Materials Science Division, BARC, Mumbai 400 085 (India); Bhambroo, Rajan [Deptt. of Metallurgical Engg. and Mat. Sci., IIT Bombay, Mumbai 400 076 (India); Kain, V. [Materials Science Division, BARC, Mumbai 400 085 (India); Shekhar, R. [CCCM, BARC, Hyderabad 500 062 (India); Dey, G.K. [Materials Science Division, BARC, Mumbai 400 085 (India); Raja, V.S. [Deptt. of Metallurgical Engg. and Mat. Sci., IIT Bombay, Mumbai 400 076 (India)

2012-02-15

Highlights: Black-Right-Pointing-Pointer GD-QMS studies of high temperature oxide film formed on Alloy 690. Black-Right-Pointing-Pointer Defect density reduced with increase in temperature. Black-Right-Pointing-Pointer Electrochemical behaviour of oxide film correlated to the Cr-content in oxide. - Abstract: High temperature passivation studies on Alloy 690 were carried out in lithiated water at 250 Degree-Sign C, 275 Degree-Sign C and 300 Degree-Sign C for 72 h. The passive films were characterized by glow discharge-quadrupole mass spectroscopy (GD-QMS) for compositional variation across the depth and micro laser Raman spectroscopy for oxide composition on the surface. The defect density in the oxide films was established from the Mott-Schottky analysis using electrochemical impedance spectroscopy. Electrochemical experiments at room temperature in chloride medium revealed best passivity behaviour by the oxide film formed at 300 Degree-Sign C for 72 h. The electrochemical studies were correlated to the chromium (and oxygen) content of the oxide films. Autoclaving at 300 Degree-Sign C resulted in the best passive film formation on Alloy 690 in lithiated water.

Thin films of molecular materials synthesized from fisher's carbene ferrocenyl: Film formation and electrical properties

International Nuclear Information System (INIS)

Sanchez-Vergara, M.E.; Ortiz, A.; Alvarez-Toledano, C.; Moreno, A.; Alvarez, J.R.

2008-01-01

The synthesis of materials from Fisher's carbene ferrocenyl of the elements chromium, molybdenum and tungsten was carried out. The Fisher's compounds that were synthesized included the following combinations of two different metallic atoms: iron with chromium, iron with molybdenum and iron with tungsten. The molecular solids' preparation was done in electro-synthesis cells with platinum electrodes. Thin films were prepared by vacuum thermal evaporation on quartz substrates and crystalline silicon wafers. Pellets and thin films from these compounds were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, energy-dispersive spectroscopy, atomic force microscopy and ellipsometry. The powder and thin films synthesized from these materials show the same intra-molecular bonds shown by infrared spectroscopy results, suggesting that thermal evaporation does not alter these bonds in spite of the thin films being amorphous, in contrast with other bimetallic complexes where material decomposition occurs. The differences in the conductivity values of the prepared films are very small, so they may be attributed to the different metallic ions employed in each case. The tungsten complex exhibits a higher conductivity than the molybdenum and chromium complexes at room temperature. Electrical conductivity values found for thin films are higher than for pellets made of the same molecular materials

Predicting molybdenum toxicity to higher plants: Influence of soil properties

Energy Technology Data Exchange (ETDEWEB)

McGrath, S.P., E-mail: steve.mcgrath@bbsrc.ac.u [Soil Science Department, Centre for Soils and Ecosystems Functions, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ (United Kingdom); Mico, C. [Soil Science Department, Centre for Soils and Ecosystems Functions, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ (United Kingdom); Curdy, R. [Laboratory for Environmental Biotechnology (LBE), Swiss Federal Institute of Technology Lausanne (EPFL) Station 6 CH, 1015 Lausanne (Switzerland); Zhao, F.J. [Soil Science Department, Centre for Soils and Ecosystems Functions, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ (United Kingdom)

2010-10-15

The effect of soil properties on the toxicity of molybdenum (Mo) to four plant species was investigated. Soil organic carbon or ammonium-oxalate extractable Fe oxides were found to be the best predictors of the 50% effective dose (ED{sub 50}) of Mo in different soils, explaining > 65% of the variance in ED{sub 50} for four species except for ryegrass (26-38%). Molybdenum concentrations in soil solution and consequently plant uptake were increased when soil pH was artificially raised because sorption of Mo to amorphous oxides is greatly reduced at high pH. The addition of sulphate significantly decreased Mo uptake by oilseed rape. For risk assessment, we suggest that Mo toxicity values for plants should be normalised using soil amorphous iron oxide concentrations. - Amorphous iron oxides or organic carbon were found to be the best predictors of the toxicity threshold values of Mo to higher plants on different soils.

Thermal oxidation of Zr–Cu–Al–Ni amorphous metal thin films

International Nuclear Information System (INIS)

Oleksak, R.P.; Hostetler, E.B.; Flynn, B.T.; McGlone, J.M.; Landau, N.P.; Wager, J.F.; Stickle, W.F.; Herman, G.S.

2015-01-01

The initial stages of thermal oxidation for Zr–Cu–Al–Ni amorphous metal thin films were investigated using X-ray photoelectron spectroscopy, transmission electron microscopy and energy dispersive X-ray spectroscopy. The as-deposited films had oxygen incorporated during sputter deposition, which helped to stabilize the amorphous phase. After annealing in air at 300 °C for short times (5 min) this oxygen was found to segregate to the surface or buried interface. Annealing at 300 °C for longer times leads to significant composition variation in both vertical and lateral directions, and formation of a surface oxide layer that consists primarily of Zr and Al oxides. Surface oxide formation was initially limited by back-diffusion of Cu and Ni ( 30 min). The oxidation properties are largely consistent with previous observations of Zr–Cu–Al–Ni metallic glasses, however some discrepancies were observed which could be explained by the unique sample geometry of the amorphous metal thin films. - Highlights: • Thermal oxidation of amorphous Zr–Cu–Al–Ni thin films was investigated. • Significant short-range inhomogeneities were observed in the amorphous films. • An accumulation of Cu and Ni occurs at the oxide/metal interface. • Diffusion of Zr was found to limit oxide film growth.

CuOX thin films by direct oxidation of Cu films deposited by physical vapor deposition

Directory of Open Access Journals (Sweden)

D. Santos-Cruz

Full Text Available Thin films of Cu2O and CuO oxides were developed by direct oxidation of physical vapor deposited copper films in an open atmosphere by varying the temperature in the range between 250 and 400 °C. In this work, the influence of oxidation temperature on structural, optical and electrical properties of copper oxide films has been discussed. The characterization results revealed that at lower temperatures (<300 °C, it is feasible to obtained coper (I oxide whereas at temperatures higher than 300 °C, the copper (II oxide is formed. The band gap is found to vary in between 1.54 and 2.21 eV depending on the oxidation temperature. Both oxides present p-type electrical conductivity. The carrier concentration has been increased as a function of the oxidation temperature from 1.61 × 1012 at 250 °C to 6.8 × 1012 cm−3 at 400 °C. The mobility has attained its maximum of 34.5 cm2 V−1 s−1 at a temperature of 300 °C, and a minimum of 13.8 cm2 V−1 s−1 for 400 °C. Finally, the resistivity of copper oxide films decreases as a function of oxidation temperature from 5.4 × 106 to 2.4 × 105 Ω-cm at 250 and 400 °C, respectively. Keywords: PVD, Oxidizing annealed treatment, Non-toxic material

The influence of Ac parameters in the process of micro-arc oxidation film electric breakdown

Directory of Open Access Journals (Sweden)

Ma Jin

2016-01-01

Full Text Available This paper studies the electric breakdown discharge process of micro-arc oxidation film on the surface of aluminum alloy. Based on the analysis of the AC parameters variation in the micro-arc oxidation process, the following conclusions can be drawn: The growth of oxide film can be divided into three stages, and Oxide film breakdown discharge occurs twice in the micro-arc oxidation process. The first stage is the formation and disruptive discharge of amorphous oxide film, producing the ceramic oxide granules, which belong to solid dielectric breakdown. In this stage the membrane voltage of the oxide film plays a key role; the second stage is the formation of ceramic oxide film, the ceramic oxide granules turns into porous structure oxide film in this stage; the third stage is the growth of ceramic oxide film, the gas film that forms in the oxide film’s porous structure is electric broken-down, which is the second breakdown discharge process, the current density on the oxide film surface could affect the breakdown process significantly.

Photoconduction in silicon rich oxide films

Energy Technology Data Exchange (ETDEWEB)

Luna-Lopez, J A; Carrillo-Lopez, J; Flores-Gracia, F J; Garcia-Salgado, G [CIDS-ICUAP, Benemerita Universidad Autonoma de Puebla. Ed. 103 D and C, col. San Manuel, Puebla, Pue. Mexico 72570 (Mexico); Aceves-Mijares, M; Morales-Sanchez, A, E-mail: jluna@buap.siu.m, E-mail: jluna@inaoep.m [INAOE, Luis Enrique Erro No. 1, Apdo. 51, Tonantzintla, Puebla, Mexico 72000 (Mexico)

2009-05-01

Photoconduction of silicon rich oxide (SRO) thin films were studied by current-voltage (I-V) measurements, where ultraviolet (UV) and white (Vis) light illumination were applied. SRO thin films were deposited by low pressure chemical vapour deposition (LPCVD) technique, using SiH{sub 4} (silane) and N{sub 2}O (nitrous oxide) as reactive gases at 700 {sup 0}. The gas flow ratio, Ro = [N{sub 2}O]/[SiH{sub 4}] was used to control the silicon excess. The thickness and refractive index of the SRO films were 72.0 nm, 75.5 nm, 59.1 nm, 73.4 nm and 1.7, 1.5, 1.46, 1.45, corresponding to R{sub o} = 10, 20, 30 and 50, respectively. These results were obtained by null ellipsometry. Si nanoparticles (Si-nps) and defects within SRO films permit to obtain interesting photoelectric properties as a high photocurrent and photoconduction. These effects strongly depend on the silicon excess, thickness and structure type. Two different structures (Al/SRO/Si and Al/SRO/SRO/Si metal-oxide-semiconductor (MOS)-like structures) were fabricated and used as devices. The photocurrent in these structures is dominated by the generation of carriers due to the incident photon energies ({approx}3.0-1.6 eV and 5 eV). These structures showed large photoconductive response at room temperature. Therefore, these structures have potential applications in optoelectronics devices.

Molybdenum extraction from copper-molybdenum ores

International Nuclear Information System (INIS)

Nevaeva, L.M.

1982-01-01

Molybdenum extraction from copper-molybdenum ores as practised in different countries is reviewed. In world practice the production process including depression of copper and iron sulfides and flotation of molybdenite is widely spread. At two USA factories the process of a selective flotation with molybdenite depression by dextrin is used

Molybdenum peroxo complex. Structure and thermal behavior

Energy Technology Data Exchange (ETDEWEB)

Segawa, Koichi; Ooga, Katsumi; Kurusu, Yasuhiko

1984-10-01

The molybdenum peroxide (Mo-y) prepared by oxidation of molybdenum metal with hydrogen peroxide has been studied to determine its structure and thermal behavior. Temperature programmed decomposition has been used to study the thermal stability of Mo-y. Two distinct peaks, I and II, of decomposition processes are discernible in Mo-y. Peak I corresponds to the elimination of water of crystallization and peak II to the decomposition of a peroxide ion of Mo-y. IR and UV examinations support the results of the thermal analysis. The IR band at 931 cm/sup -1/ and the UV band at 381 nm show the same thermal behavior. Both bands are attributable to the peroxide ion of Mo-y. Spectroscopic studies show that Mo-y has the tetrahedral coordination derived from the single molybdenum complex, which has double bond oxygens attached to Mo atom and has a symmetric type of peroxide ion with one water of crystallization.

Influence of oxidation state on the pH dependence of hydrous iridium oxide films

International Nuclear Information System (INIS)

Steegstra, Patrick; Ahlberg, Elisabet

2012-01-01

Many electrochemical reactions taking place in aqueous solution consume or produce protons. The pH in the diffusion layer can therefore be significantly altered during the reaction and there is a need for in situ pH measurements tracing this near surface pH. In the present paper the rotating ring disc technique was used to measure near surface pH changes during oxygen reduction, utilising hydrous iridium oxide as the pH sensing probe. Before such experiments a good understanding of the pH sensing properties of these films is required and the impact of the oxidation state of the film on the pH sensing properties was investigated as well as the influence of solution redox species. The pH sensitivity (depicted by dE/dpH) was found to depend on the average oxidation state of the film in a manner resembling the cyclic voltammetry response. In all cases the pH response is “supernernstian” with more than one proton per electron. The origin of this behaviour is discussed in the context of acid-base properties of the film and the existence of both hydrous and anhydrous oxide phases. The pH response depends also on the redox properties of the solution but can be optimised for various purposes by conditioning the film at different potentials. This was clearly illustrated by adding hydrogen peroxide, an intermediate in the oxygen reduction reaction, to the solution. It was shown that hydrous iridium oxide can be used as a reliable in situ pH sensor provided that care is taken to optimise the oxidation state of the film.

The role of polymer films on the oxidation of magnetite nanoparticles

Science.gov (United States)

Letti, C. J.; Paterno, L. G.; Pereira-da-Silva, M. A.; Morais, P. C.; Soler, M. A. G.

2017-02-01

A detailed investigation about the role of polymer films on the oxidation process of magnetite nanoparticles (∼7 nm diameter), under laser irradiation is performed employing micro Raman spectroscopy. To support this investigation, Fe3O4-np are synthesized by the co-precipitation method and assembled layer-by-layer with sodium sulfonated polystyrene (PSS). Polymer films (Fe3O4-np/PSS)n with n=2,3,5,7,10 and 25 bilayers are employed as a model system to study the oxidation process under laser irradiation. Raman data are further processed by principal component analysis. Our findings suggest that PSS protects Fe3O4-np from oxidation when compared to powder samples, even for the sample with the greater number of bilayers. Further, the oxidation of magnetite to maghemite occurs preferably for thinner films up to 7 bilayers, while the onset for the formation of the hematite phase depends on the laser intensity for thicker films. Water takes part on the oxidation processes of magnetite, the oxidation/phase transformation of Fe3O4-np is intensified in films with more bilayers, since more water is included in those films. Encapsulation of Fe3O4-np by PSS in layer-by-layer films showed to be very efficient to avoid the oxidation process in nanosized magnetite.

Growth and thermal oxidation of Ru and ZrO2 thin films as oxidation protective layers

NARCIS (Netherlands)

Coloma Ribera, R.

2017-01-01

This thesis focuses on the study of physical and chemical processes occurring during growth and thermal oxidation of Ru and ZrO2 thin films. Acting as oxidation resistant capping materials to prevent oxidation of layers underneath, these films have several applications, i.e., in microelectronics

Construction of reduced graphene oxide supported molybdenum carbides composite electrode as high-performance anode materials for lithium ion batteries

Energy Technology Data Exchange (ETDEWEB)

Chen, Minghua; Zhang, Jiawei [Key Laboratory of Engineering Dielectric and Applications (Ministry of Education), and School of Applied Science, Harbin University of Science and Technology, Harbin 150080 (China); Chen, Qingguo, E-mail: qgchen@263.net [Key Laboratory of Engineering Dielectric and Applications (Ministry of Education), and School of Applied Science, Harbin University of Science and Technology, Harbin 150080 (China); Qi, Meili [Key Laboratory of Engineering Dielectric and Applications (Ministry of Education), and School of Applied Science, Harbin University of Science and Technology, Harbin 150080 (China); Xia, Xinhui, E-mail: helloxxh@zju.edu.cn [State Key Laboratory of Silicon Materials, Key Laboratory of Advanced Materials and Applications for Batteries of Zhejiang Province, and School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China)

2016-01-15

Highlights: • Reduced graphene oxide supported molybdenum carbides are prepared by two-step strategy. • A unique sheet-on-sheet integrated nanostructure is favorable for fast ion/electron transfer. • The integrated electrode shows excellent Li ion storage performance. - Abstract: Metal carbides are emerging as promising anodes for advanced lithium ion batteries (LIBs). Herein we report reduced graphene oxide (RGO) supported molybdenum carbides (Mo{sub 2}C) integrated electrode by the combination of solution and carbothermal methods. In the designed integrated electrode, Mo{sub 2}C nanoparticles are uniformly dispersed among graphene nanosheets, forming a unique sheet-on-sheet integrated nanostructure. As anode of LIBs, the as-prepared Mo{sub 2}C-RGO integrated electrode exhibits noticeable electrochemical performances with a high reversible capacity of 850 mAh g{sup −1} at 100 mA g{sup −1}, and 456 mAh g{sup −1} at 1000 mA g{sup −1}, respectively. Moreover, the Mo{sub 2}C-RGO integrated electrode shows excellent cycling life with a capacity of ∼98.6 % at 1000 mA g{sup −1} after 400 cycles. Our research may pave the way for construction of high-performance metal carbides anodes of LIBs.

The role of polymer films on the oxidation of magnetite nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Letti, C.J. [Universidade de Brasilia, Instituto de Fisica, 70910-000 Brasilia, DF (Brazil); Paterno, L.G. [Universidade de Brasilia, Instituto de Quimica, 70910-000 Brasilia, DF (Brazil); Pereira-da-Silva, M.A. [Instituto de Fisica de São Carlos, USP, 13560-9700 São Carlos, SP (Brazil); Centro Universitario Central Paulista – UNICEP, 13563-470 São Carlos, SP (Brazil); Morais, P.C. [Universidade de Brasilia, Instituto de Fisica, 70910-000 Brasilia, DF (Brazil); Soler, M.A.G., E-mail: soler@unb.br [Universidade de Brasilia, Instituto de Fisica, 70910-000 Brasilia, DF (Brazil)

2017-02-15

A detailed investigation about the role of polymer films on the oxidation process of magnetite nanoparticles (∼7 nm diameter), under laser irradiation is performed employing micro Raman spectroscopy. To support this investigation, Fe{sub 3}O{sub 4}-np are synthesized by the co-precipitation method and assembled layer-by-layer with sodium sulfonated polystyrene (PSS). Polymer films (Fe{sub 3}O{sub 4}-np/PSS){sub n} with n=2,3,5,7,10 and 25 bilayers are employed as a model system to study the oxidation process under laser irradiation. Raman data are further processed by principal component analysis. Our findings suggest that PSS protects Fe{sub 3}O{sub 4}-np from oxidation when compared to powder samples, even for the sample with the greater number of bilayers. Further, the oxidation of magnetite to maghemite occurs preferably for thinner films up to 7 bilayers, while the onset for the formation of the hematite phase depends on the laser intensity for thicker films. Water takes part on the oxidation processes of magnetite, the oxidation/phase transformation of Fe{sub 3}O{sub 4}-np is intensified in films with more bilayers, since more water is included in those films. Encapsulation of Fe{sub 3}O{sub 4}-np by PSS in layer-by-layer films showed to be very efficient to avoid the oxidation process in nanosized magnetite. - Graphical abstract: Encapsulation of Fe{sub 3}O{sub 4}-np by PSS in layer-by-layer films avoids the oxidation and phase transformation of nanosized magnetite. - Highlights: • (Fe{sub 3}O{sub 4}-np/PSS){sub n} nanofilms, with n=2 up to 25, where layer-by-layer assembled. • The influence of film architecture on the Fe{sub 3}O{sub 4}-np oxidation was investigated through Raman spectroscopy. • Encapsulation of Fe{sub 3}O{sub 4}-np by PSS showed to be very efficient to avoid the Fe{sub 3}O{sub 4}-np oxidation.

Molybdenum-containing acidic catalysts to convert cellulosic biomass to glycolic acid

KAUST Repository

Han, Yu

2014-09-30

Embodiments of the present invention include methods and compositions related to catabolic conversion of cellulosic biomass to glycolic acid using molybdenum-containing acidic catalysts. The invention includes the use of heteropoly and isopoly acids and salts as the molybdenum-containing multi-functional catalysts for biomass conversion. In embodiments of the invention, the reactions employ successive hydrolysis, retro-aldol fragmentation, and selective oxidation in a noble metal-free system.

Synthesis and luminescent properties of PEO/lanthanide oxide nanoparticle hybrid films

Energy Technology Data Exchange (ETDEWEB)

Goubard, F. [LPPI, Universite de Cergy-Pontoise, 5 Mail Gay-Lussac, Neuville-sur-Oise, 95031 Cergy-Pontoise cedex (France)]. E-mail: fabrice.goubard@u-cergy.fr; Vidal, F. [LPPI, Universite de Cergy-Pontoise, 5 Mail Gay-Lussac, Neuville-sur-Oise, 95031 Cergy-Pontoise cedex (France); Bazzi, R. [LPCML, Universite Lyon 1, 43 Bd. du 11 Novembre 1918, 69622 Villeurbanne (France); Tillement, O. [LPCML, Universite Lyon 1, 43 Bd. du 11 Novembre 1918, 69622 Villeurbanne (France); Nano-H, 23 rue Royal, 69001 Lyon (France); Chevrot, C. [LPPI, Universite de Cergy-Pontoise, 5 Mail Gay-Lussac, Neuville-sur-Oise, 95031 Cergy-Pontoise cedex (France); Teyssie, D. [LPPI, Universite de Cergy-Pontoise, 5 Mail Gay-Lussac, Neuville-sur-Oise, 95031 Cergy-Pontoise cedex (France)

2007-10-15

In this study, we investigate the optical properties of lanthanide oxide nanoparticles dispersed in poly(ethylene oxide) (PEO) network as thermally stable polymeric films. The aim of this work is both to keep a good optical transparency in the visible domain and to obtain luminescent materials after incorporation of nanoparticles. For this purpose, we develop luminescent nanocrystals of oxides containing terbium ion as a doping element in Gd{sub 2}O{sub 3}. These sub-5-nm lanthanide oxides nanoparticles have been prepared by direct oxide precipitation in high-boiling polyalcohol solutions and characterized by luminescence spectroscopy. PEO/lanthanide oxide nanohybrid films are prepared by radical polymerization of poly(ethylene glycol) methacrylate after introduction of lanthanide oxide particles. As a first result; the obtained films present interesting luminescence properties with a very low lanthanide oxide content (up to 0.29 wt%). Furthermore, these films are still transparent and keep their original mechanical properties. Prior to describe the specific applications to optical use, we report here the dynamic mechanical analysis (DMA), X-ray diffraction (XRD) analysis, transmission electron microscopy (TEM), and luminescent properties of. nanohybrid films.

Study of oxide/metal/oxide thin films for transparent electronics and solar cells applications by spectroscopic ellipsometry

Directory of Open Access Journals (Sweden)

Mihaela Girtan

2017-05-01

Full Text Available A comprehensive study of a class of Oxide/Metal/Oxide (Oxide = ITO, AZO, TiO2 and Bi2O3, Metal = Au thin films was done by correlating the spectrophotometric studies with the ellispometric models. Films were deposited by successive sputtering from metallic targets In:Sn, Zn:Al, Ti and Bi in reactive atmosphere (for the oxide films and respective inert atmosphere (for the metallic Au interlayer films on glass substrates. The measurements of optical constants n—the refractive index and k—the extinction coefficient, at different incident photon energies for single oxide films and also for the three layers films oxide/metal/oxide samples were made using the spectroscopic ellipsometry (SE technique. The ellipsometry modelling process was coupled with the recorded transmission spectra data of a double beam spectrophotometer and the best fitting parameters were obtained not only by fitting the n and k experimental data with the dispersion fitting curves as usual is practiced in the most reported data in literature, but also by comparing the calculated the transmission coefficient from ellipsometry with the experimental values obtained from direct spectrophotometry measurements. In this way the best dispersion model was deduced for each sample. Very good correlations were obtained for the other different thin films characteristics such as the films thickness, optical band gap and electrical resistivity obtained by other measurements and calculation techniques. The ellipsometric modelling, can hence give the possibility in the future to predict, by ellipsometric simulations, the proper device architecture in function of the preferred optical and electrical properties.

Thin film ionic conductors based on cerium oxide

International Nuclear Information System (INIS)

Haridoss, P.; Hellstrom, E.; Garzon, F.H.; Brown, D.R.; Hawley, M.

1994-01-01

Fluorite and perovskite structure cerium oxide based ceramics are a class of materials that may exhibit good oxygen ion and/or protonic conductivity. The authors have successfully deposited thin films of these materials on a variety of substrates. Interesting orientation relationships were noticed between cerium oxide films and strontium titanate bi-crystal substrates. Near lattice site coincidence theory has been used to study these relationships

Valence control of cobalt oxide thin films by annealing atmosphere

International Nuclear Information System (INIS)

Wang Shijing; Zhang Boping; Zhao Cuihua; Li Songjie; Zhang Meixia; Yan Liping

2011-01-01

The cobalt oxide (CoO and Co 3 O 4 ) thin films were successfully prepared using a spin-coating technique by a chemical solution method with CH 3 OCH 2 CH 2 OH and Co(NO 3 ) 2 .6H 2 O as starting materials. The grayish cobalt oxide films had uniform crystalline grains with less than 50 nm in diameter. The phase structure is able to tailor by controlling the annealing atmosphere and temperature, in which Co 3 O 4 thin film was obtained by annealing in air at 300-600, and N 2 at 300, and transferred to CoO thin film by raising annealing temperature in N 2 . The fitted X-ray photoelectron spectroscopy (XPS) spectra of the Co2p electrons are distinguishable from different valence states of cobalt oxide especially for their satellite structure. The valence control of cobalt oxide thin films by annealing atmosphere contributes to the tailored optical absorption property.

Impedance measurements on oxide films on aluminium obtained by pulsed tensions

Energy Technology Data Exchange (ETDEWEB)

Belmokre, K. [Lab. of Applied Chemical, Dept. of Chemie, Skikda University, BP 26 - 21000 Skikda (Algeria); Azzouz, N. [Dept. of Industrial Chemie, Jijel University Center, 18000 Jijel (Algeria); Hannani, A. [Lab. Electrochem. Corros. Institute of Chemical USTHB Alger (Algeria); Pagetti, J. [Lab. LCMI, Franche-Comte - University UFR Sciences and Technical 16, Gray street - 25030 Besancon Cedex (France)

2003-01-01

We have performed this study on oxide films sealed or not in boiling water. The films are first obtained on type 1050 A aluminium substrate by pulsed tensions anodizing technique, in a sulfuric acid solution. Afterwards the, Electrochemical Impedance Spectroscopy (EIS) is employed to appreciate the films behaviour in a neutral solution of 3.5% K{sub 2}SO{sub 4}, in which the interface processes interest only the ageing phenomenon of the oxide films and not their corrosion. We have also attempted a correlation between pulse parameters of anodization and the electrical parameters characterizing these films. The sealing influence on ageing has been studied as well. For all films, ageing is appreciated using impedance diagrams evolution versus time. The results show: - the existence of two capacitive loops confirming the presence of two oxide layers characteristic of oxide films obtained in a sulfuric acid medium. The first loop, at high frequencies, is related to the external porous layer and the second one, at lower frequencies, is related to the internal barrier layer. - the thickness of the barrier layer varies between 25 and 40 nm in relation with the electrical pulse parameters. - the sealing acts favorably against anodic oxide films ageing. (Abstract Copyright [2003], Wiley Periodicals, Inc.)

Characterizations of photoconductivity of graphene oxide thin films

Directory of Open Access Journals (Sweden)

Shiang-Kuo Chang-Jian

2012-06-01

Full Text Available Characterizations of photoresponse of a graphene oxide (GO thin film to a near infrared laser light were studied. Results showed the photocurrent in the GO thin film was cathodic, always flowing in an opposite direction to the initial current generated by the preset bias voltage that shows a fundamental discrepancy from the photocurrent in the reduced graphene oxide thin film. Light illumination on the GO thin film thus results in more free electrons that offset the initial current. By examining GO thin films reduced at different temperatures, the critical temperature for reversing the photocurrent from cathodic to anodic was found around 187°C. The dynamic photoresponse for the GO thin film was further characterized through the response time constants within the laser on and off durations, denoted as τon and τoff, respectively. τon for the GO thin film was comparable to the other carbon-based thin films such as carbon nanotubes and graphenes. τoff was, however, much larger than that of the other's. This discrepancy was attributable to the retardation of exciton recombination rate thanks to the existing oxygen functional groups and defects in the GO thin films.

Electrochemistry and biochemistry of molybdenum. Ehlektrokhimiya i biokhimiya molibdena

Energy Technology Data Exchange (ETDEWEB)

Ryzhov, A M; Zajtsev, P M; Mambetkaziev, E A; Zhdanov, S I

1992-07-01

Using the review of data on polarographic behaviour of double and ternary systems molybdenum(6)-oxidant-organic ligand (oxy- and aminoacids of protein composition) by way of example, the possibility to use the metal ferments for the study of peculiarities in behaviour of the metal ions manifested in reactions was considered. The content of molybdenum in organism is noticeably different for healthy people and patients with malignant neoplasms and diabetes mellitus. There is a certain relation between catalytic activity of the metal ions and multiplicity of their accumulation in human organism.

Electrodeposited porous and amorphous copper oxide film for application in supercapacitor

Energy Technology Data Exchange (ETDEWEB)

Patake, V.D. [Thin Film Physics Laboratory, Department of Physics, Shivaji University, Kolhapur 416004, (M.S.) (India); Joshi, S.S. [Clean Energy Research Center, Korea Institute of Science and Technology, Cheongryang, Seoul 130-650 (Korea, Republic of); Lokhande, C.D. [Thin Film Physics Laboratory, Department of Physics, Shivaji University, Kolhapur 416004, (M.S.) (India); Clean Energy Research Center, Korea Institute of Science and Technology, Cheongryang, Seoul 130-650 (Korea, Republic of)], E-mail: l_chandrakant@yahoo.com; Joo, Oh-Shim [Clean Energy Research Center, Korea Institute of Science and Technology, Cheongryang, Seoul 130-650 (Korea, Republic of)], E-mail: joocat@kist.rre.kr

2009-03-15

In present study, the porous amorphous copper oxide thin films have been deposited from alkaline sulphate bath. The cathodic electrodeposition method was employed to deposit copper oxide film at room temperature on stainless steel substrate. Their structural and surface morphological properties were investigated by means of X-ray diffraction (XRD) and scanning electron micrograph (SEM), respectively. To propose this as a new material for possible application in the supercapacitor, its electrochemical properties have been studied in aqueous 1 M Na{sub 2}SO{sub 4} electrolyte using cyclic voltammetry. The structural analysis from XRD pattern showed the formation of amorphous copper oxide film on the substrate. The surface morphological studies from scanning electron micrographs revealed the formation of porous cauliflower-like copper oxide film. The cyclic voltammetric curves showed symmetric nature and increase in capacitance with increase in film thickness. The maximum specific capacitance of 36 F g{sup -1} was exhibited for the 0.6959 mg cm{sup -2} film thickness. This shows that low-cost copper oxide electrode will be a potential application in supercapacitor.

Characterization of zirconium alloy oxidation films by alternating current impedance

International Nuclear Information System (INIS)

Rosecrans, P.M.

1984-01-01

Kinetics of zirconium alloy oxidation are highly nonlinear. The results of electrochemical measurements and electron microscopy support the existence of porosity in oxide films formed on zirconium alloys in high temperature aqueous environments. Analytical treatment is presented relating oxidation kinetics to the thickness and distribution of nonporous elements within the oxide. This analysis illustrates that both the level and distribution of porosity within the oxide factor into oxidation kinetics. The barrier layer model can provide a basis for predicting the effect of environmental changes on oxidation rate. In addition, it demonstrates the need for further research into porosity generation mechanisms in oxide films

Characterization of zirconium alloy oxidation films by alternating current impedance

International Nuclear Information System (INIS)

Rosecrans, P.M.

1983-11-01

Kinetics of zirocnium alloy oxidation are highly nonlinear. The results of electrochemical measurements and electron microscopy support the existence of porosity in oxide films formed on zirconium alloys in high temperature aqueous environments. Analytical treatment is presented relating oxidation kinetics to the thickness and distribution of nonporous elements within the oxide. This analysis illustrates that both the level and distribution of porosity within the oxide factor into oxidation kinetics. The barrier layer model can provide a basis for predicting the effect of environmental changes on oxidation rate. In addition, it demonstrates the need for further research into porosity generation mechanisms in oxide films

On the mechanism of self-deceleration of the thin oxide film growth

CERN Document Server

Mukhambetov, D G

2002-01-01

The objective of this work was to investigate the kinetics of the two-phase oxide film growth on the alpha-Fe surface at temperatures of 650-750 K. We experimentally determined that the film thickness (h)-time oxidation (tau) relationship in the range denoted above is a logarithmic function, whereas Cabrera and Mott's theory gives a square law of film growth. In our work, analytical treatment of experimental data was made based on this theory, but we propose that self-deceleration of the film growth is caused not by attenuation of the electric intensity in the film because of an increase of h but by the shielding influence of the space charge of diffusing ions and electrons in that oxide film. With that purpose in view, the Debye shielding distance for plasma substance state in the oxide film was taken into consideration. The logarithmic law of oxide film growth was derived. Estimated calculations of this law's parameters were made that quantitatively correspond with literature data. The results obtained were...

Bloodcompatibility improvement of titanium oxide film modified by phosphorus ion implantation

International Nuclear Information System (INIS)

Yang, P.; Leng, Y.X.; Zhao, A.S.; Zhou, H.F.; Xu, L.X.; Hong, S.; Huang, N.

2006-01-01

Our recent investigation suggested that Ti-O thin film could be a newly developed antithrombotic material and its thromboresistance could be related to its physical properties of wide gap semiconductor. In this work, titanium oxide film was modified by phosphorus ion implantation and succeeding vacuum annealing. RBS were used to investigate phosphorus distribution profile. Contact angle test results show that phosphorus-doped titanium oxide film becomes more hydrophilic after higher temperature annealing, while its electric conductivity increases. Antithrombotic property of phosphorus-doped titanium oxide thin films was examined by clotting time and platelet adhesion tests. The results suggest that phosphorus doping is an effective way to improve the bloodcompatibility of titanium oxide film, and it is related to the changes of electron structure and surface properties caused by phosphorus doping

Principal component analysis of NEXAFS spectra for molybdenum speciation in hydrotreating catalysts

International Nuclear Information System (INIS)

Faro Junior, Arnaldo da C.; Rodrigues, Victor de O.; Eon, Jean-G.; Rocha, Angela S.

2010-01-01

Bulk and supported molybdenum based catalysts, modified by nickel, phosphorous or tungsten were studied by NEXAFS spectroscopy at the Mo L III and L II edges. The techniques of principal component analysis (PCA) together with a linear combination analysis (LCA) allowed the detection and quantification of molybdenum atoms in two different coordination states in the oxide form of the catalysts, namely tetrahedral and octahedral coordination. (author)

Peculiarities of phase transformations in molybdenum-silicon system under ion bombardment

International Nuclear Information System (INIS)

Gurskij, L.I.; Zelenin, V.A.; Bobchenok, Yu.L.

1984-01-01

The problems of effect of ion bombardment and thermal treatment on the mechanisms of formation of transition layers and structural transformations in the molybdenum-silicon system, where the interface is subjected to ion bombardment through a film of molybdenum, are considered. The method of electron diffraction analysis has been applied to establish that at the molybdenum-silicon interface a transitional region appears during irradiation which has a semiamorphous structure at the doses up to 8x10 14 ion/cm 2 , while at higher doses it transforms into polycrystalline intermediate layer which consists of MoB and the compound close in composition to MoSisub(0.65). Due to thermal treatment for 60873 K a large-grain phase (Mo 3 Si+MoSi 2 ) appears in the transition layer below which a large-grain silicon layer is placed

Cleavage and formation of molecular dinitrogen in a single system assisted by molybdenum complexes bearing ferrocenyldiphosphine.

Science.gov (United States)

Miyazaki, Takamasa; Tanaka, Hiromasa; Tanabe, Yoshiaki; Yuki, Masahiro; Nakajima, Kazunari; Yoshizawa, Kazunari; Nishibayashi, Yoshiaki

2014-10-20

The N≡N bond of molecular dinitrogen bridging two molybdenum atoms in the pentamethylcyclopentadienyl molybdenum complexes that bear ferrocenyldiphosphine as an auxiliary ligand is homolytically cleaved under visible light irradiation at room temperature to afford two molar molybdenum nitride complexes. Conversely, the bridging molecular dinitrogen is reformed by the oxidation of the molybdenum nitride complex at room temperature. This result provides a successful example of the cleavage and formation of molecular dinitrogen induced by a pair of two different external stimuli using a single system assisted by molybdenum complexes bearing ferrocenyldiphosphine under ambient conditions. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Laser-Induced, Local Oxidation of Copper Nanoparticle Films During Raman Measurements

Science.gov (United States)

Hight Walker, Angela R.; Cheng, Guangjun; Calizo, Irene

2011-03-01

The optical properties of gold and silver nanoparticles and their films have been thoroughly investigated as surface enhanced Raman scattering (SERS) substrates and chemical reaction promoters. Similar to gold and silver nanoparticles, copper nanoparticles exhibit distinct plasmon absorptions in the visible region. The work on copper nanoparticles and their films is limited due to their oxidization in air. However, their high reactivity actually provides an opportunity to exploit the laser-induced thermal effect and chemical reactions of these nanoparticles. Here, we present our investigation of the local oxidation of a copper nanoparticle film induced by a visible laser source during Raman spectroscopic measurements. The copper nanoparticle film is prepared by drop-casting chemically synthesized copper colloid onto silicon oxide/silicon substrate. The local oxidation induced by visible lasers in Raman spectroscopy is monitored with the distinct scattering peaks for copper oxides. Optical microscopy and scanning electron microscopy have been used to characterize the laser-induced morphological changes in the film. The results of this oxidation process with different excitation wavelengths and different laser powers will be presented.

Deposition and characterisation of epitaxial oxide thin films for SOFCs

KAUST Repository

Santiso, José

2010-10-24

This paper reviews the recent advances in the use of thin films, mostly epitaxial, for fundamental studies of materials for solid oxide fuel cell (SOFC) applications. These studies include the influence of film microstructure, crystal orientation and strain in oxide ionic conducting materials used as electrolytes, such as fluorites, and in mixed ionic and electronic conducting materials used as electrodes, typically oxides with perovskite or perovskite-related layered structures. The recent effort towards the enhancement of the electrochemical performance of SOFC materials through the deposition of artificial film heterostructures is also presented. These thin films have been engineered at a nanoscale level, such as the case of epitaxial multilayers or nanocomposite cermet materials. The recent progress in the implementation of thin films in SOFC devices is also reported. © 2010 Springer-Verlag.

Thin films of molecular materials synthesized from fisher's carbene ferrocenyl: Film formation and electrical properties

Energy Technology Data Exchange (ETDEWEB)

Sanchez-Vergara, M.E. [Coordinacion de Ingenieria Mecatronica. Escuela de Ingenieria, Universidad Anahuac del Norte. Avenida Lomas de la Anahuac s/n, Col. Lomas Anahuac, 52786, Huixquilucan (Mexico)], E-mail: elena.sanchez@anahuac.mx; Ortiz, A. [Instituto de Investigaciones en Materiales. Universidad Nacional Autonoma de Mexico. A. P. 70-360, 04510, Mexico, DF (Mexico); Alvarez-Toledano, C.; Moreno, A. [Instituto de Quimica, Universidad Nacional Autonoma de Mexico. Circuito Exterior, Ciudad Universitaria, 04510, Mexico, DF (Mexico); Alvarez, J.R. [Instituto Tecnologico y de Estudios Superiores de Monterrey, Campus Ciudad de Mexico. Calle del Puente 222, Col. Ejidos de Huipulco, 14380, Mexico, DF (Mexico)

2008-07-31

The synthesis of materials from Fisher's carbene ferrocenyl of the elements chromium, molybdenum and tungsten was carried out. The Fisher's compounds that were synthesized included the following combinations of two different metallic atoms: iron with chromium, iron with molybdenum and iron with tungsten. The molecular solids' preparation was done in electro-synthesis cells with platinum electrodes. Thin films were prepared by vacuum thermal evaporation on quartz substrates and crystalline silicon wafers. Pellets and thin films from these compounds were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, energy-dispersive spectroscopy, atomic force microscopy and ellipsometry. The powder and thin films synthesized from these materials show the same intra-molecular bonds shown by infrared spectroscopy results, suggesting that thermal evaporation does not alter these bonds in spite of the thin films being amorphous, in contrast with other bimetallic complexes where material decomposition occurs. The differences in the conductivity values of the prepared films are very small, so they may be attributed to the different metallic ions employed in each case. The tungsten complex exhibits a higher conductivity than the molybdenum and chromium complexes at room temperature. Electrical conductivity values found for thin films are higher than for pellets made of the same molecular materials.

Effect of mass density on surface morphology of electrodeposited manganese oxide films

Science.gov (United States)

Singh, Avtar; Kumar, Davinder; Thakur, Anup; Kaur, Raminder

2018-05-01

This work focus on high surface area morphology of manganese oxide films which are currently required for electrochemical capacitor electrode to enhance their performance. Electrodeposition of manganese oxide films was carried out using Chronoamperometry for different deposition time ranging from 30 to 120 sec. Cronoamperomertic I-T integrated data have been used to analyze active mass of all electrodeposited films. Morphological study of the deposited films with different mass was carried out through scanning electron microscopy. Film deposited for 30 sec time show highest porous morphology than others. Manganese oxide films with high porosity are suitable for electrochemical capacitor electrode.

A density-functional theory approach to the existence and stability of molybdenum and tungsten sesquioxide polymorphs

Energy Technology Data Exchange (ETDEWEB)

Becker, Nils; Dronskowski, Richard [RWTH Aachen Univ. (Germany). Inst. fuer Anorganische Chemie; RWTH Aachen Univ. (Germany). Juelich-Aachen Research Alliance; Reimann, Christoph; Bredow, Thomas [Bonn Univ. (Germany). Inst. fuer Physikalische und Theoretische Chemie; Weber, Dominik; Luedtke, Tobias; Lerch, Martin [Berlin Technische Univ. (Germany). Inst. fuer Chemie

2017-03-01

The sesquioxides of molybdenum and tungsten have been reported as thin films or on surfaces as early as 1971, but the preparation of bulk materials and their crystal structures are still unknown up to the present day. We present a systematic ab initio approach to their possible syntheses and crystal structures applying complementary methods and basis-set types. For both compounds, the corundum structure is the most stable and does not display any imaginary frequencies. Calculations targeted at a high-pressure synthesis starting from the stable oxides and metals predict a reaction pressure of 15 GPa for Mo{sub 2}O{sub 3} and over 60 GPa for W{sub 2}O{sub 3}.

Recovery of uranium and molybdenum elements from gebel gattar raw material, eastern desert, Egypt. Vol. 3

Energy Technology Data Exchange (ETDEWEB)

El-Hazek, N T; Mahdy, M A; Mahmoud, H M.K. [Nuclear Materials Authority, Cairo, (Egypt)

1996-03-01

G. Gatter uranium mineralizations are located along the faults and fracture zones crossing G.Gattar granitic pluton and long the contact of the pluton with the hammamat sediments. Also, molybdenum id presented in more than one mode of occurrence. The molybdenum mineralization treated in this work is the dessimenated type. The uranium and molybdenum raw material was subjected to series of leaching experiments including acid and alkaline agitation, alkaline percolation, and acid heap leaching techniques. Recovery of uranium and molybdenum was achieved by anion-exchange method followed by their elution by acidified sodium chloride. Uranium precipitation was performed in the form of ammonium diuranate (Yellow Cake). On the other hand molybdenum was precipitated in the form of molybdenum oxide. A tentative flowsheet for the extraction of both uranium and molybdenum is proposed and discussed. 13 figs., 3 tabs.

Recovery of uranium and molybdenum elements from gebel gattar raw material, eastern desert, Egypt. Vol. 3

International Nuclear Information System (INIS)

El-Hazek, N.T.; Mahdy, M.A.; Mahmoud, H.M.K.

1996-01-01

G. Gatter uranium mineralizations are located along the faults and fracture zones crossing G.Gattar granitic pluton and long the contact of the pluton with the hammamat sediments. Also, molybdenum id presented in more than one mode of occurrence. The molybdenum mineralization treated in this work is the dessimenated type. The uranium and molybdenum raw material was subjected to series of leaching experiments including acid and alkaline agitation, alkaline percolation, and acid heap leaching techniques. Recovery of uranium and molybdenum was achieved by anion-exchange method followed by their elution by acidified sodium chloride. Uranium precipitation was performed in the form of ammonium diuranate (Yellow Cake). On the other hand molybdenum was precipitated in the form of molybdenum oxide. A tentative flowsheet for the extraction of both uranium and molybdenum is proposed and discussed. 13 figs., 3 tabs

Tantalum oxide thin films as protective coatings for sensors

DEFF Research Database (Denmark)

Christensen, Carsten; Reus, Roger De; Bouwstra, Siebe

1999-01-01

Reactively sputtered tantalum oxide thin films have been investigated as protective coatings for aggressive media exposed sensors. Tantalum oxide is shown to be chemically very robust. The etch rate in aqueous potassium hydroxide with pH 11 at 140°C is lower than 0.008 Å h-l. Etching in liquids...... with pH values in the range from pH 2 to 11 have generally given etch rates below 0.04 Å h-l. On the other hand patterning is possible in hydrofluoric acid. Further, the passivation behaviour of amorphous tantalum oxide and polycrystalline Ta2O5 is different in buffered hydrofluoric acid. By ex situ...... annealing O2 in the residual thin-film stress can be altered from compressive to tensile and annealing at 450°C for 30 minutes gives a stress-free film. The step coverage of the sputter deposited amorphous tantalum oxide is reasonable, but metallization lines are hard to cover. Sputtered tantalum oxide...

Tantalum oxide thin films as protective coatings for sensors

DEFF Research Database (Denmark)

Christensen, Carsten; Reus, Roger De; Bouwstra, Siebe

1999-01-01

Reactively sputtered tantalum oxide thin-films have been investigated as protective coating for aggressive media exposed sensors. Tantalum oxide is shown to be chemically very robust. The etch rate in aqueous potassium hydroxide with pH 11 at 140°C is lower than 0.008 Å/h. Etching in liquids with p......H values in the range from pH 2-11 have generally given etch rates below 0.04 Å/h. On the other hand patterning is possible in hydrofluoric acid. Further, the passivation behaviour of amorphous tantalum oxide and polycrystalline Ta2O5 is different in buffered hydrofluoric acid. By ex-situ annealing in O2...... the residual thin-film stress can be altered from compressive to tensile and annealing at 450°C for 30 minutes gives a stress-free film. The step coverage of the sputter deposited amorphous tantalum oxide is reasonable, but metallisation lines are hard to cover. Sputtered tantalum oxide exhibits high...

Aluminum oxide film thickness and emittance

International Nuclear Information System (INIS)

Thomas, J.K.; Ondrejcin, R.S.

1991-11-01

Aluminum reactor components which are not actively cooled could be subjected to high temperatures due to gamma heating after the core coolant level dropped during the ECS phase of a hypothetical LOCA event. Radiative heat transfer is the dominant heat transfer process in this scenario and therefore the emittance of these components is of interest. Of particular interest are the safety rod thimbles and Mark 60B blanket assemblies; for the K Reactor, these components have been exposed to low temperature (< 55 degrees C) moderator for about a year. The average moderator temperature was assumed to be 30 degrees C. The Al oxide film thickness at this temperature, after one year of exposure, is predicted to be 6.4 μm ± 10%; insensitive to exposure time. Dehydration of the film during the gamma heating accident would result in a film thickness of 6.0 μm ± 11%. Total hemispherical emittance is predicted to be 0.69 at 96 degrees C, decreasing to 0.45 at 600 degrees C. Some phenomena which would tend to yield thicker oxide films in the reactor environment relative to those obtained under experimental conditions were neglected and the predicted film thickness values are therefore conservative. The emittance values predicted for a given film thickness are also conservative. The conservativisms inherent in the predicted emittance are particularly relevant for uncertainty analysis of temperatures generated using these values

Photoconductivity of reduced graphene oxide and graphene oxide composite films

International Nuclear Information System (INIS)

Liang, Haifeng; Ren, Wen; Su, Junhong; Cai, Changlong

2012-01-01

A photoconductive device was fabricated by patterning magnetron sputtered Pt/Ti electrode and Reduced Graphene Oxide (RGO)/Graphene Oxide (GO) composite films with a sensitive area of 10 × 20 mm 2 . The surface morphology of as-deposited GO films was observed by scanning electronic microscopy, optical microscopy and atomic force microscopy, respectively. The absorption properties and chemical structure of RGO/GO composite films were obtained using a spectrophotometer and an X-ray photoelectron spectroscopy. The photoconductive properties of the system were characterized under white light irradiation with varied output power and biased voltage. The results show that the resistance decreased from 210 kΩ to 11.5 kΩ as the irradiation power increased from 0.0008 mW to 625 mW. The calculated responsiveness of white light reached 0.53 × 10 −3 A/W. Furthermore, the device presents a high photo-conductivity response and displays a photovoltaic response with an open circuit voltage from 0.017 V to 0.014 V with irradiation power. The sources of charge are attributed to efficient excitation dissociation at the interface of the RGO/GO composite film, coupled with cross-surface charge percolation.

Up-gradation of MoO{sub 3} and separation of copper, iron, zinc from roasted molybdenum ore by a leaching process

Energy Technology Data Exchange (ETDEWEB)

Jin-Young, Lee; Jyothi Rajesh, Kumar; Ho-Seok, Jeon; Joon-Soo, Kim, E-mail: rajeshkumarphd@rediffmail.com, E-mail: rkumarphd@kigam.re.kr [Extractive Metallurgy Department, Mineral Resources Research Division, Korea Institute of Geoscience and Mineral Resources (KIGAM) (Korea, Republic of)

2013-04-15

The present research paper deals with the oxidation process of molybdenum ore. The main target of the present study is the up-gradation of MoO{sub 3} from roasted molybdenum ore by a leaching process without waste generation. The most important application of hydrometallurgical processing is the leaching process of the ore and it is the primary process to make pure metal from ore. The present investigations optimize the following experimental parameters to improve the concentration of MoO{sub 3} as well as the separation of copper, iron and zinc in roasted molybdenum ore: effect of acid concentration, temperature, pulp density and leaching time were studied systematically. The temperature study was carried out at 550-595 Degree-Sign C for the oxidation process. The XRD result shows that oxidation process of molybdenum ore and SEM pictures were taken for particles before and after the oxidation process at 585 Degree-Sign C for 360 min. (author)

Ductility Enhancement of Molybdenum Phase by Nano-sizedd Oxide Dispersions

Energy Technology Data Exchange (ETDEWEB)

Bruce Kang

2008-07-31

The present research is focused on ductility enhancement of molybdenum (Mo) alloys by adding nano-sized oxide particles to the alloy system. The research approach includes: (1) determination of microscopic mechanisms responsible for the macroscopic ductility enhancement effects through atomistic modeling of the metal-ceramic interface; (2) subsequent computer simulation-aided optimization of composition and nanoparticle size of the dispersion for improved performance; (3) synthesis and characterization of nanoparticle dispersion following the guidance from atomistic computational modeling analyses (e.g., by processing a small sample of Mo alloy for evaluation); and (4) experimental testing of the mechanical properties to determine optimal ductility enhancement.Through atomistic modeling and electronic structure analysis using full-potential linearized muffin-tin orbital (FP-LMTO) techniques, research to date has been performed on a number of selected chromium (Cr) systems containing nitrogen (N) and/or magnesium oxide (MgO) impurities. The emphasis has been on determining the properties of the valence electrons and the characteristics of the chemical bonds they formed. It was found that the brittle/ductile behavior of this transitional metal system is controlled by the relative population of valence charges: bonds formed by s valence electrons yield metallic, ductile behavior, whereas bonds formed by d valence electrons lead to covalent, brittle behavior. The presence of valence bands from impurities also affects the metal bonding, thereby explaining the detrimental and beneficial effects induced by the inclusion of N impurities and MgO dispersions. These understandings are useful for optimizing ductility enhancement effects on the dispersion materials.

Spectrographic analysis of uranium-molybdenum alloys; Analisis espectrografico de aleaciones uranio-molibdeno

Energy Technology Data Exchange (ETDEWEB)

Roca, M

1967-07-01

A spectrographic method of analysis has been developed for uranium-molybdenum alloys containing up to 10 % Mo. The carrier distillation technique, with gallium oxide and graphite as carriers, is used for the semiquantitative determination of Al, Cr, Fe, Ni and Si, involving the conversion of the samples into oxides. As a consequence of the study of the influence of the molybdenum on the line intensities, it is useful to prepare only one set of standards with 0,6 % MoO{sub 3}. Total burning excitation is used for calcium, employing two sets of standards with 0,6 and 7.5 MoO{sub 3}. (Author) 5 refs.

Valence control of cobalt oxide thin films by annealing atmosphere

Energy Technology Data Exchange (ETDEWEB)

Wang Shijing [School of Materials Science and Engineering, University of Science and Technology Beijing, No. 30 Xueyuan Road, Beijing 100083 (China); Zhang Boping, E-mail: bpzhang@ustb.edu.cn [School of Materials Science and Engineering, University of Science and Technology Beijing, No. 30 Xueyuan Road, Beijing 100083 (China); Zhao Cuihua; Li Songjie; Zhang Meixia; Yan Liping [School of Materials Science and Engineering, University of Science and Technology Beijing, No. 30 Xueyuan Road, Beijing 100083 (China)

2011-02-01

The cobalt oxide (CoO and Co{sub 3}O{sub 4}) thin films were successfully prepared using a spin-coating technique by a chemical solution method with CH{sub 3}OCH{sub 2}CH{sub 2}OH and Co(NO{sub 3}){sub 2}.6H{sub 2}O as starting materials. The grayish cobalt oxide films had uniform crystalline grains with less than 50 nm in diameter. The phase structure is able to tailor by controlling the annealing atmosphere and temperature, in which Co{sub 3}O{sub 4} thin film was obtained by annealing in air at 300-600, and N{sub 2} at 300, and transferred to CoO thin film by raising annealing temperature in N{sub 2}. The fitted X-ray photoelectron spectroscopy (XPS) spectra of the Co2p electrons are distinguishable from different valence states of cobalt oxide especially for their satellite structure. The valence control of cobalt oxide thin films by annealing atmosphere contributes to the tailored optical absorption property.

Spark counting technique of alpha tracks on an aluminium oxide film

International Nuclear Information System (INIS)

Morishima, Hiroshige; Koga, Taeko; Niwa, Takeo; Kawai, Hiroshi

1984-01-01

We have tried to use aluminium oxide film as a neutron detector film with a spark counter for neutron monitoring in the mixed field of neutron and gamma-rays near a reactor. The merits of this method are that (1) aluminium oxide is good electric insulator, (2) any desired thickness of the film can be prepared, (3) chemical etching of the thin film can be dispensed with. The relation between spark counts and numbers of alpha-particles which entered the aluminium oxide film 1 μm thick was linear in the range of 10 5 -10 7 alpha-particles. The sensitivity(ratio of the spark counts to irradiated numbers of alpha-particles) was approximately 10 -3 . (author)

Intrinsic stress of bismuth oxide thin films: effect of vapour chopping and air ageing

International Nuclear Information System (INIS)

Patil, R B; Puri, R K; Puri, V

2008-01-01

Bismuth oxide thin films of thickness 1000 A 0 have been prepared by thermal oxidation (in air) of vacuum evaporated bismuth thin films (on glass substrate) at different oxidation temperatures and duration. Both the vapour chopped and nonchopped bismuth oxide thin films showed polycrystalline and polymorphic structure. The monoclinic bismuth oxide was found to be predominant in both the cases. The effect of vapour chopping and air exposure for 40 days on the intrinsic stress of bismuth oxide thin films has been studied. The vapour chopped films showed low (3.92 - 4.80 x 10 9 N/m 2 ) intrinsic stress than those of nonchopped bismuth oxide thin films (5.77 - 6.74 x 10 9 N/m 2 ). Intrinsic stress was found to increase due to air ageing. The effect of air ageing on the vapour chopped films was found low. The vapour chopped films showed higher packing density. Higher the packing density, lower the film will age. The process of chopping vapour flow creates films with less inhomogenety i.e. a low concentration of flaws and non-planar defects which results in lower intrinsic stress

Effects of the Molybdenum Oxide/Metal Anode Interfaces on Inverted Polymer Solar Cells

International Nuclear Information System (INIS)

Wu Jiang; Guo Xiao-Yang; Xie Zhi-Yuan

2012-01-01

Inverted polymer solar cells with molybdenum oxide (MoO 3 ) as an anode buffer layer and different metals (Al or Ag) as anodes are studied. It is found that the inverted cell with a top Ag anode demonstrates enhanced charge collection and higher power conversion efficiency (PCE) compared to the cell with a top Al anode. An 18% increment of PCE is obtained by replacing Al with Ag as the top anode. Further studies show that an interfacial dipole pointing from MoO 3 to Al is formed at MoO 3 /Al interfaces due to electron transfer from Al to MoO 3 while this phenomenon cannot be observed at MoO 3 /Ag interfaces. It is speculated that the electric field at the MoO 3 /Al interface would hinder hole extraction, and hence reduce the short-circuit current

Atomic Layer-Deposited Molybdenum Oxide/Carbon Nanotube Hybrid Electrodes: The Influence of Crystal Structure on Lithium-Ion Capacitor Performance.

Science.gov (United States)

Fleischmann, Simon; Zeiger, Marco; Quade, Antje; Kruth, Angela; Presser, Volker

2018-05-25

Merging of supercapacitors and batteries promises the creation of electrochemical energy storage devices that combine high specific energy, power, and cycling stability. For that purpose, lithium-ion capacitors (LICs) that store energy by lithiation reactions at the negative electrode and double-layer formation at the positive electrode are currently investigated. In this study, we explore the suitability of molybdenum oxide as a negative electrode material in LICs for the first time. Molybdenum oxide-carbon nanotube hybrid materials were synthesized via atomic layer deposition, and different crystal structures and morphologies were obtained by post-deposition annealing. These model materials are first structurally characterized and electrochemically evaluated in half-cells. Benchmarking in LIC full-cells revealed the influences of crystal structure, half-cell capacity, and rate handling on the actual device level performance metrics. The energy efficiency, specific energy, and power are mainly influenced by the overpotential and kinetics of the lithiation reaction during charging. Optimized LIC cells show a maximum specific energy of about 70 W·h·kg -1 and a high specific power of 4 kW·kg -1 at 34 W·h·kg -1 . The longevity of the LIC cells is drastically increased without significantly reducing the energy by preventing a deep cell discharge, hindering the negative electrode from crossing its anodic potential limit.

Thickness Dependence of Optoelectrical Properties of Mo-Doped In2O3 Films Deposited on Polyethersulfone Substrates by Ion-Beam-Assisted Evaporation

Directory of Open Access Journals (Sweden)

Chin-Chiuan Kuo

2010-01-01

Full Text Available Indium molybdenum oxide (IMO films were deposited onto the polyethersulfone (PES substrates by ion-beam-assisted evaporation (IBAE deposition at low temperature in this study. The effects of film thickness on their optical and electrical properties were investigated. The results show that the deposited IMO films exhibit a preferred orientation of B(222. The electrical resistivity of the deposited film initially reduces then subsequently increases with film thickness. The IMO film with the lowest resistivity of 7.61 × 10−4 ohm-cm has been achieved when the film thickness is 120 nm. It exhibits a satisfactory surface roughness pv of 8.75 nm and an average visible transmittance of 78.7%.

Zinc-oxide nanorod / copper-oxide thin-film heterojunction for a nitrogen-monoxide gas sensor

International Nuclear Information System (INIS)

Yoo, Hwansu; Kim, Hyojin; Kim, Dojin

2014-01-01

A novel p - n oxide heterojunction structure was fabricated by employing n-type zinc-oxide (ZnO) nanorods grown on an indium-tin-oxide-coated glass substrate by using the hydrothermal method and a p-type copper-oxide (CuO) thin film deposited onto the ZnO nanorod array by using the sputtering method. The crystallinities and microstructures of the heterojunction materials were examined by using X-ray diffraction and scanning electron microscopy. The observed current - voltage characteristics of the p - n oxide heterojunction showed a nonlinear diode-like rectifying behavior. The effects of an oxidizing or electron acceptor gas, such as nitrogen monoxide (NO), on the ZnO nanorod/CuO thin-film heterojunction were investigated to determine the potential applications of the fabricated material for use in gas sensors. The forward current of the p - n heterojunction was remarkably reduced when NO gas was introduced into dry air at temperatures from 100 to 250 .deg. C. The NO gas response of the oxide heterojunction reached a maximum value at an operating temperature of 180 .deg. C and linearly increased as the NO gas concentration was increased from 5 to 30 ppm. The sensitivity value was observed to be as high as 170% at 180 .deg. C when biased at 2 V in the presence of 20-ppm NO. The ZnO nanorod/CuO thin-film heterojunction also exhibited a stable and repeatable response to NO gas. The experimental results suggest that the ZnO nanorod/CuO thin-film heterojunction structure may be a novel candidate for gas sensors.

Zinc-oxide nanorod / copper-oxide thin-film heterojunction for a nitrogen-monoxide gas sensor

Energy Technology Data Exchange (ETDEWEB)

Yoo, Hwansu; Kim, Hyojin; Kim, Dojin [Chungnam National University, Daejeon (Korea, Republic of)

2014-11-15

A novel p - n oxide heterojunction structure was fabricated by employing n-type zinc-oxide (ZnO) nanorods grown on an indium-tin-oxide-coated glass substrate by using the hydrothermal method and a p-type copper-oxide (CuO) thin film deposited onto the ZnO nanorod array by using the sputtering method. The crystallinities and microstructures of the heterojunction materials were examined by using X-ray diffraction and scanning electron microscopy. The observed current - voltage characteristics of the p - n oxide heterojunction showed a nonlinear diode-like rectifying behavior. The effects of an oxidizing or electron acceptor gas, such as nitrogen monoxide (NO), on the ZnO nanorod/CuO thin-film heterojunction were investigated to determine the potential applications of the fabricated material for use in gas sensors. The forward current of the p - n heterojunction was remarkably reduced when NO gas was introduced into dry air at temperatures from 100 to 250 .deg. C. The NO gas response of the oxide heterojunction reached a maximum value at an operating temperature of 180 .deg. C and linearly increased as the NO gas concentration was increased from 5 to 30 ppm. The sensitivity value was observed to be as high as 170% at 180 .deg. C when biased at 2 V in the presence of 20-ppm NO. The ZnO nanorod/CuO thin-film heterojunction also exhibited a stable and repeatable response to NO gas. The experimental results suggest that the ZnO nanorod/CuO thin-film heterojunction structure may be a novel candidate for gas sensors.

In situ hydrogenation of molybdenum oxide nanowires for enhanced supercapacitors

KAUST Repository

Shakir, Imran

2014-01-01

In situ hydrogenation of orthorhombic molybdenum trioxide (α-MoO 3) nanowires has been achieved on a large scale by introducing alcohol during the hydrothermal synthesis for electrochemical energy storage supercapacitor devices. The hydrogenated molybdenum trioxide (H xMoO3) nanowires yield a specific capacitance of 168 F g-1 at 0.5 A g-1 and maintain 108 F g-1 at 10 A g-1, which is 36-fold higher than the capacitance obtained from pristine MoO3 nanowires at the same conditions. The electrochemical devices made with HxMoO3 nanowires exhibit excellent cycling stability by retaining 97% of their capacitance after 3000 cycles due to an enhanced electronic conductivity and increased density of hydroxyl groups on the surface of the MoO3 nanowires. This journal is © The Royal Society of Chemistry.

Mechanical properties of bioplastics cassava starch film with Zinc Oxide nanofiller as reinforcement

Science.gov (United States)

Harunsyah; Yunus, M.; Fauzan, Reza

2017-06-01

This study focuses on investigating the influence of zinc oxide nanofiller on the mechanical properties of bioplastic cassava starch films. Bioplastic cassava starch film-based zinc oxide reinforced composite biopolymeric films were prepared by casting technique. The content of zinc oxide in the bioplastic films was varied from 0.2%, 0.4%, 0.6%, 0.8% and 1.0% (w/w) by weight of starch. Surface morphologies of the composites bioplastic films were examined by scanning electron microscope (SEM).The result showed that the Tensile strength (TS) was improved significantly with the additional of zinc oxide but the elongation at break (EB %) of the composites was decreased. The maximum tensile strength obtained was 22.30 kgf / mm on the additional of zinc oxide by 0.6% and plastilizer by 25%. Based on data of FTIR, the produced film plastic did not change the group function and it can be concluded that theinteraction in film plastic produced was only a physical interaction. Biodegradable plastic film based on cassava starch-zinc oxide and plasticizer glycerol showed that interesting mechanical properties being transparent, clear, homogeneous, flexible, and easily handled.

Electronic structure evolution in doping of fullerene (C{sub 60}) by ultra-thin layer molybdenum trioxide

Energy Technology Data Exchange (ETDEWEB)

Wang, Chenggong; Wang, Congcong; Kauppi, John [Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627 (United States); Liu, Xiaoliang [Institute for Super-microstructure and Ultrafast Process in Advanced Materials (ISUPAM), Central South University, Changsha, Hunan 410083 (China); Gao, Yongli, E-mail: ygao@pas.rochester.edu [Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627 (United States); Institute for Super-microstructure and Ultrafast Process in Advanced Materials (ISUPAM), Central South University, Changsha, Hunan 410083 (China)

2015-08-28

Ultra-thin layer molybdenum oxide doping of fullerene has been investigated using ultraviolet photoemission spectroscopy (UPS) and X-ray photoemission spectroscopy (XPS). The highest occupied molecular orbital (HOMO) can be observed directly with UPS. It is observed that the Fermi level position in fullerene is modified by ultra-thin-layer molybdenum oxide doping, and the HOMO onset is shifted to less than 1.3 eV below the Fermi level. The XPS results indicate that charge transfer was observed from the C{sub 60} to MoO{sub x} and Mo{sup 6+} oxides is the basis as hole dopants.

The Effects of Temperature and Oxidation on Deuterium Retention in Solid and Liquid Lithium Films on Molybdenum Plasma-Facing Components

Science.gov (United States)

Capece, Angela

2014-10-01

Liquid metal plasma-facing components (PFCs) enable in-situ renewal of the surface, thereby offering a solution to neutron damage, erosion, and thermal fatigue experienced by solid PFCs. Lithium in particular has a high chemical affinity for hydrogen, which has resulted in reduced recycling and enhanced plasma performance on many fusion devices including TFTR, T11-M, FTU, CDX-U, LTX, TJ-II, and NSTX. A key component to the improvement in plasma performance is deuterium retention in Li; however, this process is not well understood in the complex tokamak environment. Recent surface science experiments conducted at the Princeton Plasma Physics Laboratory have used electron spectroscopy and temperature programmed desorption to understand the mechanisms for D retention in Li coatings on Mo substrates. The experiments were designed to give monolayer-control of Li films and were conducted in ultrahigh vacuum under controlled environments. An electron cyclotron resonance plasma source was used to deliver a beam of deuterium ions to the surface over a range of ion energies. Our work shows that D is retained as LiD in metallic Li films. However, when oxygen is present in the film, either by diffusion from the subsurface at high temperature or as a contaminant during the deposition process, Li oxides are formed that retain D as LiOD. Experiments indicate that LiD is more thermally stable than LiOD, which decomposes to liberate D2 gas and D2O at temperatures 100 K lower than the LiD decomposition temperature. Other experiments show how D retention varies with substrate temperature to provide insight into the differences between solid and liquid lithium films. This work was supported by DOE Contract No. DE AC02-09CH11466.

Native oxidation of ultra high purity Cu bulk and thin films

International Nuclear Information System (INIS)

Iijima, J.; Lim, J.-W.; Hong, S.-H.; Suzuki, S.; Mimura, K.; Isshiki, M.

2006-01-01

The effect of microstructure and purity on the native oxidation of Cu was studied by using angle-resolved X-ray photoelectron spectroscopy (AR-XPS) and spectroscopic ellipsometry (SE). A high quality copper film prepared by ion beam deposition under a substrate bias voltage of -50 V (IBD Cu film at V s = -50 V) showed an oxidation resistance as high as an ultra high purity copper (UHP Cu) bulk, whereas a Cu film deposited without substrate bias voltage (IBD Cu film at V s = 0 V) showed lower oxidation resistance. The growth of Cu 2 O layer on the UHP Cu bulk and both types of the films obeyed in principle a logarithmic rate law. However, the growth of oxide layer on the IBD Cu films at V s = 0 and -50 V deviated upward from the logarithmic rate law after the exposure time of 320 and 800 h, respectively. The deviation from the logarithmic law is due to the formation of CuO on the Cu 2 O layer after a critical time

The disclosed transformation of pre-sputtered Ti films into nanoparticles via controlled thermal oxidation

Science.gov (United States)

Awad, M. A.; Raaif, M.

2018-05-01

Nanoparticles of TiO2 were successfully prepared from pre-sputtered Ti films using the controlled thermal oxidation. The effect of oxidation temperature on structural, morphological and optical properties in addition to photocatalysis activity of the sputtered films was tested and explained. Analysis of XRD and EDAX elucidated the enhancement in crystallization and oxygen content with the increase of oxidation temperature. SEM depicted the formation of very fine nanoparticles with no specific border on the films oxidized at 550 and 600 °C, whilst crystallites with larger size of approximately from 16 to 23 nm have been observed for the film oxidized at 650 °C. Both optical transmission and refractive index were increased with increasing the oxidation temperature. A red shift in the absorption edge was obtained for the films oxidized at 650 °C compared to that oxidized at 600 °C. The photocatalysis tests demonstrated the priority of 600 °C nanoparticle films to decompose methyl orange (MO) more than 650 °C treated film.

Preparation, characterization and electrocatalytic behavior of zinc oxide/zinchexacyanoferrate and ruthenium oxide hexacyanoferrate hybrid film-modified electrodes

Energy Technology Data Exchange (ETDEWEB)

Chu, H.-W.; Thangamuthu, R. [Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, No. 1, Section 3, Chung-Hsiao East Road, Taipei 106, Taiwan (China); Chen, S.-M. [Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, No. 1, Section 3, Chung-Hsiao East Road, Taipei 106, Taiwan (China)], E-mail: smchen78@ms15.hinet.net

2008-02-15

Polynuclear mixed-valent hybrid films of zinc oxide/zinchexacyanoferrate and ruthenium oxide hexacyanoferrate (ZnO/ZnHCF-RuOHCF) have been deposited on electrode surfaces from H{sub 2}SO{sub 4} solution containing Zn(NO{sub 3}){sub 2}, RuCl{sub 3} and K{sub 3}[Fe(CN){sub 6}] by potentiodynamic cycling method. Simultaneous cyclic voltammetry and electrochemical quartz crystal microbalance (EQCM) measurements demonstrate the steady growth of hybrid film. Surface morphology of hybrid film was investigated using scanning electron microscopy (SEM). Energy dispersive spectrometer (EDS) data confirm existence of zinc oxide and ruthenium oxide hexacyanoferrate (RuOHCF) in the hybrid film. The effect of type of monovalent cations on the redox behavior of hybrid film was investigated. In pure supporting electrolyte, electrochemical responses of Ru{sup II/III} redox transition occurring at negative potential region resemble with that of a surface immobilized redox couple. The electrocatalytic activity of ZnO/ZnHCF-RuOHCF hybrid film was investigated towards oxidation of epinephrine, dopamine and L-cysteine, and reduction of S{sub 2}O{sub 8}{sup 2-} and SO{sub 5}{sup 2-} as well as IO{sub 3}{sup -} using cyclic voltammetry and rotating ring disc electrode (RRDE) techniques.

Thin copper oxide films prepared by ion beam sputtering with subsequent thermal oxidation: Application in chemiresistors

Energy Technology Data Exchange (ETDEWEB)

Horak, P., E-mail: phorak@ujf.cas.cz [Nuclear Physics Institute, Academy of Sciences of the Czech Republic, 250 68 Řež (Czech Republic); Bejsovec, V.; Vacik, J.; Lavrentiev, V. [Nuclear Physics Institute, Academy of Sciences of the Czech Republic, 250 68 Řež (Czech Republic); Vrnata, M. [Department of Physics and Measurements, The University of Chemistry and Technology, Prague, Technická 5, 166 28 Prague 6 (Czech Republic); Kormunda, M. [Department of Physics, Jan Evangelista Purkyně University in Ústí nad Labem, České mládeže 8, 400 96 Ústí nad Labem (Czech Republic); Danis, S. [Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University in Prague, Ke Karlovu 5, 121 16 Prague 2 (Czech Republic)

2016-12-15

Highlights: • A rapid oxidation process of thin copper films. • Sheet resistance up to 10{sup 9} Ω/◊. • Mixed oxide phase at 200 °C with significant hydroxide presence. • Gas sensing response to 1000 ppm of hydrogen and methanol vapours. • Increased sensitivity with Pd and Au catalyst to hydrogen and methanol, respectively. - Abstract: Copper oxide films were prepared by thermal oxidation of thin Cu films deposited on substrates by ion beam sputtering. The subsequent oxidation was achieved in the temperature range of 200 °C–600 °C with time of treatment from 1 to 7 h (with a 1-h step) in a furnace open to air. At temperatures 250 °C–600 °C, the dominant phase formed was CuO, while at 200 °C mainly the Cu{sub 2}O phase was identified. However, the oxidation at 200 °C led to a more complicated composition − in the depth Cu{sub 2}O phase was observed, though in the near-surface layer the CuO dominant phase was found with a significant presence of Cu(OH){sub 2}. A limited amount of Cu{sub 2}O was also found in samples annealed at 600 °C. The sheet resistance R{sub S} of the as-deposited Cu sample was 2.22 Ω/□, after gradual annealing R{sub S} was measured in the range 2.64 MΩ/□–2.45 GΩ/□. The highest R{sub S} values were obtained after annealing at 300 °C and 350 °C, respectively. Oxygen depth distribution was studied using the {sup 16}O(α,α) nuclear reaction with the resonance at energy 3032 keV. It was confirmed that the higher oxidation degree of copper is located in the near-surface region. Preliminary tests of the copper oxide films as an active layer of a chemiresistor were also performed. Hydrogen and methanol vapours, with a concentration of 1000 ppm, were detected by the sensor at an operating temperature of 300 °C and 350 °C, respectively. The response of the sensors, pointed at the p-type conductivity, was improved by the addition of thin Pd or Au catalytic films to the oxidic film surface. Pd-covered films showed

Strain-induced phenomenon in complex oxide thin films

Science.gov (United States)

Haislmaier, Ryan

Complex oxide materials wield an immense spectrum of functional properties such as ferroelectricity, ferromagnetism, magnetoelectricity, optoelectricity, optomechanical, magnetoresistance, superconductivity, etc. The rich coupling between charge, spin, strain, and orbital degrees of freedom makes this material class extremely desirable and relevant for next generation electronic devices and technologies which are trending towards nanoscale dimensions. Development of complex oxide thin film materials is essential for realizing their integration into nanoscale electronic devices, where theoretically predicted multifunctional capabilities of oxides could add tremendous value. Employing thin film growth strategies such as epitaxial strain and heterostructure interface engineering can greatly enhance and even unlock novel material properties in complex oxides, which will be the main focus of this work. However, physically incorporating oxide materials into devices remains a challenge. While advancements in molecular beam epitaxy (MBE) of thin film oxide materials has led to the ability to grow oxide materials with atomic layer precision, there are still major limitations such as controlling stoichiometric compositions during growth as well as creating abrupt interfaces in multi-component layered oxide structures. The work done in this thesis addresses ways to overcome these limitations in order to harness intrinsic material phenomena. The development of adsorption-controlled stoichiometric growth windows of CaTiO3 and SrTiO3 thin film materials grown by hybrid MBE where Ti is supplied using metal-organic titanium tetraisopropoxide material is thoroughly outlined. These growth windows enable superior epitaxial strain-induced ferroelectric and dielectric properties to be accessed as demonstrated by chemical, structural, electrical, and optical characterization techniques. For tensile strained CaTiO3 and compressive strained SrTiO 3 films, the critical effects of

Modification of oxide films by ion implantation: TiO2-films modified by Ti+ and O+ as example

International Nuclear Information System (INIS)

Schultze, J.W.; Elfenthal, L.; Leitner, K.; Meyer, O.

1988-01-01

Oxide films can be modified by ion implantation. Changes in the electrochemical properties of the films are due to the deposition profile of the implanted ion, ie doping and stoichiometric changes, as well as to the radiation damage. The latter is due to the formation of Frenkel defects and at high concentrations to a complete amorphization of the oxide film. TiOsub(x)-films with 1 + - and O + -ions into anodic oxide films on titanium. The electrode capacity shows always the behaviour of an n-type semiconductor with an almost constant flatband potential but a strong maximum donor concentration at about 3% Ti + concentration. Oxygen implantation, on the other hand, causes a small increase of donor concentration only at high concentration of O + . Electron transfer reactions show strong modifications of the electronic behaviour of the oxide film with a maximum again at 3% titanium. Photocurrent spectra prove the increasing amorphization and show interband states 2.6 eV above the VB or below the CB. During repassivation measurements at various potentials different defects formed by Ti + - and O + -implantation become mobile. A tentative model of the band structure is constructed which takes into account the interband states due to localised Ti + - and O + -ions. The modification of ion implanted oxide films is compared with the effects of other preparation techniques. (author)

Formation and dissolution of the anodic oxide film on zirconium in alcoholic aqueous solutions

International Nuclear Information System (INIS)

Mogoda, A.S.

1995-01-01

The dissolution behavior of the anodic oxide film formed in alcoholic aqueous solutions was studied. Results indicated the dissolution mechanism of the duplex oxide film followed a zero-order rate equation. The increase in methanol concentration in the formation medium (phosphoric acid [H 3 PO 4 ]) resulted in formation of an oxide film that incorporated little phosphate ion and that dissolved at a low rate. The dissolution rate of the oxide film decreased with increasing methanol concentration in the dissolution medium. This was attributed to the increase in the viscosity of the medium, which led to a decrease in the diffusion coefficient of the dissolution product of the zirconium oxide film. Dissolution of the anodic oxide film also was investigated as a function of the chain length of alcohols

Swelling of a Zirconium Oxide Film

International Nuclear Information System (INIS)

Henderson, Mark; Hawley, Adrian; White, John; Rennie, Adrian

2005-01-01

Full text: The structural changes that cause the change in the interlayer spacing of a surfactanttemplated zirconium oxide film have been studied using neutron diffractometry. We report that the film after drying on a glass substrate swells slightly through the addition of benzene by up to 4 Aangstroem on a lattice parameter of about 36 Aangstroem. The (001) and (002) diffraction peaks positions, widths and areas of a swollen film were then monitored by neutron diffraction as a function of benzene desorption. Disorder of the lamellar mesophase is considered as a cause of the observed effects on the diffraction signals. (authors)

Impact of Microstructure on MoS2 Oxidation and Friction.

Science.gov (United States)

Curry, John F; Wilson, Mark A; Luftman, Henry S; Strandwitz, Nicholas C; Argibay, Nicolas; Chandross, Michael; Sidebottom, Mark A; Krick, Brandon A

2017-08-23

This work demonstrates the role of microstructure in the friction and oxidation behavior of the lamellar solid lubricant molybdenum disulfide (MoS 2 ). We report on systematic investigations of oxidation and friction for two MoS 2 films with distinctively different microstructures-amorphous and planar/highly-ordered-before and after exposure to atomic oxygen (AO) and high-temperature (250 °C) molecular oxygen. A combination of experimental tribology, molecular dynamics simulations, X-ray photoelectron spectroscopy (XPS), and high-sensitivity low-energy ion scattering (HS-LEIS) was used to reveal new insights about the links between structure and properties of these widely utilized low-friction materials. Initially, ordered MoS 2 films showed a surprising resistance to both atomic and molecular oxygens (even at elevated temperature), retaining characteristic low friction after exposure to extreme oxidative environments. XPS shows comparable oxidation of both coatings via AO; however, monolayer resolved compositional depth profiles from HS-LEIS reveal that the microstructure of the ordered coatings limits oxidation to the first atomic layer.

Films of double oxides of zirconium and iron

International Nuclear Information System (INIS)

Kozik, V.V.; Borilo, L.P.; Shul'pekov, A.M.

2000-01-01

Films of double oxides of zirconium and iron were prepared by the method of precipitation from film-forming alcohol solutions of zirconium oxychloride and iron chloride with subsequent thermal treatment. Using the methods of X-ray phase and differential thermal analyses, conductometry and optical spectroscopy, basic chemical processes occurring in the film-forming solutions and during thermal treatment are studied alongside with phase composition and optical characteristics of the films prepared. The composition-property diagrams of the given system in a thin-film state are plotted [ru

Oxidation behaviour of Ti2AIN films composed mainly of nanolaminated MAX phase.

Science.gov (United States)

Wang, Q M; Garkas, W; Renteria, A Flores; Leyens, C; Kim, K H

2011-10-01

In this paper, we reported the oxidation behaviour of Ti2AIN films on polycrystalline Al2O3 substrates. The Ti2AIN films composed mainly of nanolaminated MAX phase was obtained by first depositing Ti-Al-N films using reactive sputtering of two elemental Ti and Al targets in Ar/N2 atmosphere and subsequent vacuum annealing at 800 degrees C for 1 h. The Ti2AIN films exhibited excellent oxidation resistance and thermal stability at 600-900 degrees C in air. Very low mass gain was observed. At low temperature (600 degrees C), no oxide crystals were observed on film surface. Blade-like Theta-Al2O3 fine crystals formed on film surfaces at 700-800 degrees C. At high temperature (900 degrees C), firstly Theta-Al2O3 formed on film surface and then transformed into alpha-Al2O3. At 700-900 degrees C, a continuous Al2O3 layer formed on Ti2AIN films surface, acting as diffusion barrier preventing further oxidation attack. The mechanism of the excellent oxidation resistance of Ti2AIN films was discussed based on the experimental results.

Hybrid Co-deposition of Mixed-Valent Molybdenum-Germanium Oxides (MoxGeyOz): A Route to Tunable Optical Transmission (Postprint)

Science.gov (United States)

2015-08-05

within these films can be attrib- uted to low adatommobility related to the low deposition temperature (T ≤ 100 °C), interruption of film nucleation via...heating being applied to the substrate during deposition as well as the tendency of oxygen to act as a grain refining agent, interrupting nucleation ...heating and humidity : effect of Al oxide top coatings, Thin Solid Films 562 (2014) 568–573. [7] C. Granqvist, Electrochromic oxides: a bandstructure

Thin copper oxide films prepared by ion beam sputtering with subsequent thermal oxidation: Application in chemiresistors

Science.gov (United States)

Horak, P.; Bejsovec, V.; Vacik, J.; Lavrentiev, V.; Vrnata, M.; Kormunda, M.; Danis, S.

2016-12-01

Copper oxide films were prepared by thermal oxidation of thin Cu films deposited on substrates by ion beam sputtering. The subsequent oxidation was achieved in the temperature range of 200 °C-600 °C with time of treatment from 1 to 7 h (with a 1-h step) in a furnace open to air. At temperatures 250 °C-600 °C, the dominant phase formed was CuO, while at 200 °C mainly the Cu2O phase was identified. However, the oxidation at 200 °C led to a more complicated composition - in the depth Cu2O phase was observed, though in the near-surface layer the CuO dominant phase was found with a significant presence of Cu(OH)2. A limited amount of Cu2O was also found in samples annealed at 600 °C. The sheet resistance RS of the as-deposited Cu sample was 2.22 Ω/□, after gradual annealing RS was measured in the range 2.64 MΩ/□-2.45 GΩ/□. The highest RS values were obtained after annealing at 300 °C and 350 °C, respectively. Oxygen depth distribution was studied using the 16O(α,α) nuclear reaction with the resonance at energy 3032 keV. It was confirmed that the higher oxidation degree of copper is located in the near-surface region. Preliminary tests of the copper oxide films as an active layer of a chemiresistor were also performed. Hydrogen and methanol vapours, with a concentration of 1000 ppm, were detected by the sensor at an operating temperature of 300 °C and 350 °C, respectively. The response of the sensors, pointed at the p-type conductivity, was improved by the addition of thin Pd or Au catalytic films to the oxidic film surface. Pd-covered films showed an increased response to hydrogen at 300 °C, while Au-covered films were more sensitive to methanol vapours at 350 °C.

Nanocomposite oxide thin films grown by pulsed energy beam deposition

International Nuclear Information System (INIS)

Nistor, M.; Petitmangin, A.; Hebert, C.; Seiler, W.

2011-01-01

Highly non-stoichiometric indium tin oxide (ITO) thin films were grown by pulsed energy beam deposition (pulsed laser deposition-PLD and pulsed electron beam deposition-PED) under low oxygen pressure. The analysis of the structure and electrical transport properties showed that ITO films with a large oxygen deficiency (more than 20%) are nanocomposite films with metallic (In, Sn) clusters embedded in a stoichiometric and crystalline oxide matrix. The presence of the metallic clusters induces specific transport properties, i.e. a metallic conductivity via percolation with a superconducting transition at low temperature (about 6 K) and the melting and freezing of the In-Sn clusters in the room temperature to 450 K range evidenced by large changes in resistivity and a hysteresis cycle. By controlling the oxygen deficiency and temperature during the growth, the transport and optical properties of the nanocomposite oxide films could be tuned from metallic-like to insulating and from transparent to absorbing films.

Intrinsic stress evolution during amorphous oxide film growth on Al surfaces

International Nuclear Information System (INIS)

Flötotto, D.; Wang, Z. M.; Jeurgens, L. P. H.; Mittemeijer, E. J.

2014-01-01

The intrinsic stress evolution during formation of ultrathin amorphous oxide films on Al(111) and Al(100) surfaces by thermal oxidation at room temperature was investigated in real-time by in-situ substrate curvature measurements and detailed atomic-scale microstructural analyses. During thickening of the oxide a considerable amount of growth stresses is generated in, remarkably even amorphous, ultrathin Al 2 O 3 films. The surface orientation-dependent stress evolutions during O adsorption on the bare Al surfaces and during subsequent oxide-film growth can be interpreted as a result of (i) adsorption-induced surface stress changes and (ii) competing processes of free volume generation and structural relaxation, respectively

Effect of micro-patterned fluorine-doped tin oxide films on electrochromic properties of Prussian blue films

International Nuclear Information System (INIS)

Lee, Kyuha; Kim, A-Young; Park, Ji Hun; Jung, Hun-Gi; Choi, Wonchang; Lee, Hwa Young; Lee, Joong Kee

2014-01-01

Graphical abstract: - Highlights: • PB-based ECD employed micro-patterned FTO electrode was fabricated. • Effect of interface morphology on electrochromic characteristics was examined. • Electrochromic properties were enhanced by employing a patterned interface. - Abstract: The effect of interface morphology on electrochromic characteristics was examined for an electrochromic device (ECD). Micro-patterned fluorine-doped tin oxide (FTO) films were fabricated using a photolithography process. Prussian blue (PB) films were then deposited on the patterned FTO films. The surface areas of both PB films and FTO films were increased by patterning. ECDs were assembled using patterned PB/FTO films as the electrochromic electrode, bare FTO films as the counter electrode, and an electrolyte containing LiClO 4 salt. The increased effective surface area of the patterned PB/FTO electrode boosted the mobility of ions at the interphase between the electrolyte and PB electrode, and the electron transfer between PB films and FTO films. As a result, electrochromic properties such as transmittance and response time were significantly improved by employing the patterned FTO films as the transparent conductive oxide layer of the electrochromic electrode

Nanosecond laser scribing of CIGS thin film solar cell based on ITO bottom contact

Science.gov (United States)

Kuk, Seungkuk; Wang, Zhen; Fu, Shi; Zhang, Tao; Yu, Yi Yin; Choi, JaeMyung; Jeong, Jeung-hyun; Hwang, David J.

2018-03-01

Cu(In,Ga)Se2 (CIGS) thin films, a promising photovoltaic architecture, have mainly relied on Molybdenum for the bottom contact. However, the opaque nature of Molybdenum (Mo) poses limitations in module level fabrication by laser scribing as a preferred method for interconnect. We examined the P1, P2, and P3 laser scribing processes on CIGS photovoltaic architecture on the indium tin oxide (ITO) bottom contact with a cost-effective nanosecond pulsed laser of 532 nm wavelength. Laser illuminated from the substrate side, enabled by the transparent bottom contact, facilitated selective laser energy deposition onto relevant interfaces towards high-quality scribing. Parametric tuning procedures are described in conjunction with experimental and numerical investigation of relevant mechanisms, and preliminary mini-module fabrication results are also presented.

Polymer thin film as coating layer to prevent corrosion of metal/metal oxide film

Science.gov (United States)

Sarkar, Suman; Kundu, Sarathi

2018-04-01

Thin film of polymer is used as coating layer and the corrosion of metal/metal oxide layer is studied with the variation of the thickness of the coating layer. The thin layer of polystyrene is fabricated using spin coating method on copper oxide (CuO) film which is deposited on glass substrate using DC magnetron sputtering technique. Thickness of the polystyrene and the CuO layers are determined using X-ray reflectivity (XRR) technique. CuO thin films coated with the polystyrene layer are exposed to acetic acid (2.5 v/v% aqueous CH3COOH solution) environments and are subsequently analyzed using UV-Vis spectroscopy and atomic force microscopy (AFM). Surface morphology of the film before and after interaction with the acidic environment is determined using AFM. Results obtained from the XRR and UV-Vis spectroscopy confirm that the thin film of polystyrene acts as an anticorrosion coating layer and the strength of the coating depends upon the polymer layer thickness at a constant acid concentration.

A novel Graphene Oxide film: Synthesis and Dielectric properties

Science.gov (United States)

Canimkurbey, Betul; San, Sait Eren; Yasin, Muhammad; Köse, Muhammet Erkan

In this work, we used Hummers method to synthesize Graphene Oxide (GO) and its parallel plate impedance spectroscopic technique to investigate dielectric properties. Graphene Oxide films were coated using drop casting method on ITO substrate. To analyze film morphology, atomic force microscopy was used. Dielectrics measurements of the samples were performed using impedance analyzer (HP-4194) in frequency range (100 Hz to 10MHz) at different temperatures. It was observed that the films' AC conductivity σac varied with angular frequency, ω as ωS, with Sdirect current (DC) and Correlated Barrier Hopping (CBH) conductivity mechanisms at low and high frequency ranges, respectively. Using solution processed Graphene Oxide will provide potential for organic electronic applications through its photon absorption and transmittance capability in the visible range and excellent electrical parameters.

Preparation and characterization of nanocrystalline composites Mo-C-N hard films

Energy Technology Data Exchange (ETDEWEB)

Liu, Q. [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, POB 1129, 230031 Hefei (China); Liu, T. [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, POB 1129, 230031 Hefei (China); Fang, Q.F. [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, POB 1129, 230031 Hefei (China)]. E-mail: qffang@issp.ac.cn; Liang, F.J. [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, POB 1129, 230031 Hefei (China); Wang, J.X. [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, POB 1129, 230031 Hefei (China)

2006-05-01

Molybdenum carbonitride (MoCN) films were deposited on Si (001) and stainless steel substrates by reactive direct-current magnetron sputtering with a molybdenum and graphite composite target. By changing the substrate temperature and the N{sub 2} / Ar ratio in the sputtering gas, it is found that good quality MoCN films can be deposited at substrate temperature of 300-400 deg. C under N{sub 2} partial pressure of 0.25-0.5 Pa with a total working pressure of 1 Pa. The structures of the films deposited at such conditions were determined by X-ray diffraction and X-ray photoelectron spectroscopy analysis as nanocrystalline molybdenum carbonitride with a grain size of several ten nanometers was embedded in the amorphous matrix of C and CN {sub x}. The hardness of the MoCN films can reach 28 GPa, much higher than the value of MoC and MoN films alone.

Effects of iron content on electrical resistivity of oxide films on Zr-base alloys

International Nuclear Information System (INIS)

Kubo, Toshio; Uno, Masayoshi

1991-01-01

Measurements of electrical resistivity were made for oxide films formed by anodic oxidation and steam oxidation (400degC/12 h) on Zr plates with different Fe contents. When the Fe content was higher than about 1,000 ppm the electrical resistivity of the steam oxide films was almost equivalent to that of the anodic oxide films, while at lower Fe content the former exhibited lower electrical resistivity than the latter by about 1∼3 orders of magnitude. The anodic oxide film was an almost homogeneous single oxide layer. The steam oxide films, on the other hand, were composed of duplex oxide layers. The oxide layer formed in the vicinity of the oxide/metal interface had higher electrical resistivity than the near-surface oxide layer by about 1∼4 orders of magnitude. The oxide layer in the vicinity of the interface could act as a protective film against corrosion and its electrical resistivity is one important factor controlling the layer protectiveness. The electrical resistivity of the oxide/metal interfacial layer was strongly dependent on the Fe content. One possible reason for Fe to improve the corrosion resistance is that Fe ions would tend to stabilize the tetragonal (or cubic) phase and consequently suppress the formation of open pores and cracks in the interfacial layer. (author)

A nanogravimmetric investigation of the charging processes on ruthenium oxide thin films and their effect on methanol oxidation

International Nuclear Information System (INIS)

Santos, M.C.; Cogo, L.; Tanimoto, S.T.; Calegaro, M.L.; Bulhoes, L.O.S

2006-01-01

The charging processes and methanol oxidation that occur during the oxidation-reduction cycles in a ruthenium oxide thin film electrode (deposited by the sol-gel method on Pt covered quartz crystals) were investigated by using cyclic voltammetry, chronoamperometry and electrochemical quartz crystal nanobalance techniques. The ruthenium oxide rutile phase structure was determined by X-ray diffraction analysis. The results obtained during the charging of rutile ruthenium oxide films indicate that in the anodic sweep the transition from Ru(II) to Ru(VI) occurs followed by proton de-intercalation. In the cathodic sweep, electron injection occurs followed by proton intercalation, leading to Ru(II). The proton intercalation/de-intercalation processes can be inferred from the mass/charge relationship which gives a slope close to 1 g mol -1 (multiplied by the Faraday constant) corresponding to the molar mass of hydrogen. From the chronoamperometric measurements, charge and mass saturation of the RuO 2 thin films was observed (440 ng cm -2 ) during the charging processes, which is related to the total number of active sites in these films. Using the electrochemical quartz crystal nanobalance technique to study the methanol oxidation reaction at these films was possible to demonstrate that bulk oxidation occurs without the formation of strongly adsorbed intermediates such as CO ads , demonstrating that Pt electrodes modified by ruthenium oxide particles can be promising catalysts for the methanol oxidation as already shown in the literature

Controllable film densification and interface flatness for high-performance amorphous indium oxide based thin film transistors

Energy Technology Data Exchange (ETDEWEB)

Ou-Yang, Wei, E-mail: OUYANG.Wei@nims.go.jp, E-mail: TSUKAGOSHI.Kazuhito@nims.go.jp; Mitoma, Nobuhiko; Kizu, Takio; Gao, Xu; Lin, Meng-Fang; Tsukagoshi, Kazuhito, E-mail: OUYANG.Wei@nims.go.jp, E-mail: TSUKAGOSHI.Kazuhito@nims.go.jp [International Center for Materials Nanoarchitectronics (WPI-MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Nabatame, Toshihide [MANA Foundry and MANA Advanced Device Materials Group, National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)

2014-10-20

To avoid the problem of air sensitive and wet-etched Zn and/or Ga contained amorphous oxide transistors, we propose an alternative amorphous semiconductor of indium silicon tungsten oxide as the channel material for thin film transistors. In this study, we employ the material to reveal the relation between the active thin film and the transistor performance with aid of x-ray reflectivity study. By adjusting the pre-annealing temperature, we find that the film densification and interface flatness between the film and gate insulator are crucial for achieving controllable high-performance transistors. The material and findings in the study are believed helpful for realizing controllable high-performance stable transistors.

On the interaction of molybdenum cyanide complexes with hydroperoxide of tertiary butyl

International Nuclear Information System (INIS)

Vretsena, N.B.; Nikipanchuk, M.V.; Chernyak, B.I.

1979-01-01

Conducted is investigation of interaction of potassium dioxotetracyanomolybdate (4) K 4 [MoO 2 (CN) 4 ], potassium oxotetracyanomolybdate (2) K 4 [MoO(CN) 4 ] and potassium tetracyanomolybdate K 4 [Mo(CN) 4 ] in CCl 4 and hydroperoxide of tertiary butyl medium, (HPTB). Shown is the process complex mechanism which leads to molybdenum oxidation in complexes and also to coordination and HPTB decomposition. Calculated are parameters of complex formation process of molybdenum with HPTB cyanide complexes

Influences of the main anodic electroplating parameters on cerium oxide films

Energy Technology Data Exchange (ETDEWEB)

Yang, Yang; Yang, Yumeng; Du, Xiaoqing; Chen, Yu [Department of Chemistry, Zhejiang University, Hangzhou 310027, Zhejiang (China); Zhang, Zhao, E-mail: eaglezzy@zjuem.zju.edu.cn [Department of Chemistry, Zhejiang University, Hangzhou 310027, Zhejiang (China); Zhang, Jianqing [Department of Chemistry, Zhejiang University, Hangzhou 310027, Zhejiang (China); State Key Laboratory for Corrosion and Protection of Metals, Shenyang 110016 (China)

2014-06-01

Cerium oxide thin films were fabricated onto 316 L stainless steel via a potentiostatically anodic electrodeposition approach in the solutions containing cerium(III) nitrate (0.05 M), ammonia acetate (0.1 M) and ethanol (10% V/V). The electrochemical behaviors and deposition parameters (applied potential, bath temperature, dissolving O{sub 2} and bath pH) have been investigated. Results show that, the electrochemical oxidation of Ce{sup 3+} goes through one electrochemical step, which is under charge transfer control. The optimum applied potential for film deposition is 0.8 V. Bath temperature plays a significant effect on the deposition rate, composition (different colors of the film) and surface morphology of the deposits. Due to the hydrolysis of Ce{sup 3+}, cerous hydroxide is facility to form when the bath temperature is higher than 60 °C. The electroplating bath pH is another key role for the anodic deposition of cerium oxide thin films, and the best bath pH is around 6.20. N{sub 2} or O{sub 2} purged into the bath will result in film porosities and O{sub 2} favors cerium oxide particles and film generation.

Microstructure and protection characteristics of the naturally formed oxide films on Mg–xZn alloys

International Nuclear Information System (INIS)

Song, Yingwei; Han, En-Hou; Dong, Kaihui; Shan, Dayong; Yim, Chang Dong; You, Bong Sun

2013-01-01

Highlights: •The oxide films on Mg–xZn alloys consist of similar chemical composition. •The higher Zn content results in the thicker but higher defect of the oxide films. •The oxide films exhibit different protection performance under various potentials. -- Abstract: The naturally formed oxide films on Mg–2Zn and Mg–5Zn alloys were investigated by atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and electrochemical measurements. The oxide films on the both alloys present a similar chemical composition, consisting of surface layer of basic magnesium carbonate and MgO following with MgO and ZnO, but the oxide film on Mg–5Zn is thicker and contains more defects. The protection performance of the oxide film on Mg–5Zn is worse under open circuit potential but better in a suitable anodic potential scope compared with that on Mg–2Zn alloy

Magnetic properties of partially oxidized Fe films

Science.gov (United States)

Garcia, Miguel Angel; Lopez-Dominguez, Victor; Hernando, Antonio

Hybrid magnetic nanostructures exhibit appealing properties due to interface and proximity effects. A simple and interesting system of hybrid magnetic nanomaterials are partially oxidized ferromagnetic films. We have fabricated Fe films by thermal evaporation and performed a partial oxidation to magnetite (Fe3O4) by annealing in air at different times and temperatures. The magnetic properties of the films evolve from those of pure metallic iron to pure magnetite, showing intermediate states where the proximity effects control the magnetic behavior. At some stages, the magnetization curves obtained by SQUID and MOKE magnetometry exhibit important differences due to the dissimilar contribution of both phases to the magneto-optical response of the system This work has been supported by the Ministerio Español de Economia y Competitividad (MINECO) MAT2013-48009-C4-1. V.L.D and M.A.G. acknowledges financial support from BBVA foundation.

Surfactant-assisted ultrasonic spray pyrolysis of nickel oxide and lithium-doped nickel oxide thin films, toward electrochromic applications

Energy Technology Data Exchange (ETDEWEB)

Denayer, Jessica [Group of Research in Energy and Environment for MATerials (GREENMAT), University of Liège, allée de la chimie 3, 4000 Liège (Belgium); Bister, Geoffroy [Environmental and Material Research Association (CRIBC-INISMa), avenue gouverneur cornez 4, 7000 Mons (Belgium); Simonis, Priscilla [Laboratory LPS, University of Namur, rue de bruxelles 61, 5000 Namur (Belgium); Colson, Pierre; Maho, Anthony [Group of Research in Energy and Environment for MATerials (GREENMAT), University of Liège, allée de la chimie 3, 4000 Liège (Belgium); Aubry, Philippe [Environmental and Material Research Association (CRIBC-INISMa), avenue gouverneur cornez 4, 7000 Mons (Belgium); Vertruyen, Bénédicte [Group of Research in Energy and Environment for MATerials (GREENMAT), University of Liège, allée de la chimie 3, 4000 Liège (Belgium); Henrist, Catherine, E-mail: catherine.henrist@ulg.ac.be [Group of Research in Energy and Environment for MATerials (GREENMAT), University of Liège, allée de la chimie 3, 4000 Liège (Belgium); Lardot, Véronique; Cambier, Francis [Environmental and Material Research Association (CRIBC-INISMa), avenue gouverneur cornez 4, 7000 Mons (Belgium); Cloots, Rudi [Group of Research in Energy and Environment for MATerials (GREENMAT), University of Liège, allée de la chimie 3, 4000 Liège (Belgium)

2014-12-01

Highlights: • Surfactant-assisted USP: a novel and low cost process to obtain high quality nickel oxide films, with or without lithium dopant. • Increased uniformity and reduced light scattering thanks to the addition of a surfactant. • Improved electrochromic performance (coloration efficiency and contrast) for lithium-doped films by comparison with the undoped NiO film. - Abstract: Lithium-doped nickel oxide and undoped nickel oxide thin films have been deposited on FTO/glass substrates by a surfactant-assisted ultrasonic spray pyrolysis. The addition of polyethylene glycol in the sprayed solution has led to improved uniformity and reduced light scattering compared to films made without surfactant. Furthermore, the presence of lithium ions in NiO films has resulted in improved electrochromic performances (coloration contrast and efficiency), but with a slight decrease of the electrochromic switching kinetics.

Amorphous semiconducting and conducting transparent metal oxide thin films and production thereof

Science.gov (United States)

Perkins, John; Van Hest, Marinus Franciscus Antonius Maria; Ginley, David; Taylor, Matthew; Neuman, George A.; Luten, Henry A.; Forgette, Jeffrey A.; Anderson, John S.

2010-07-13

Metal oxide thin films and production thereof are disclosed. An exemplary method of producing a metal oxide thin film may comprise introducing at least two metallic elements and oxygen into a process chamber to form a metal oxide. The method may also comprise depositing the metal oxide on a substrate in the process chamber. The method may also comprise simultaneously controlling a ratio of the at least two metallic elements and a stoichiometry of the oxygen during deposition. Exemplary amorphous metal oxide thin films produced according to the methods herein may exhibit highly transparent properties, highly conductive properties, and/or other opto-electronic properties.

Lipase immobilized on nanostructured cerium oxide thin film coated on transparent conducting oxide electrode for butyrin sensing

International Nuclear Information System (INIS)

Panky, Sreedevi; Thandavan, Kavitha; Sivalingam, Durgajanani; Sethuraman, Swaminathan; Krishnan, Uma Maheswari; Jeyaprakash, Beri Gopalakrishnan; Rayappan, John Bosco Balaguru

2013-01-01

Nanostructured cerium oxide (CeO 2 ) thin films were deposited on transparent conducting oxide (TCO) substrate using spray pyrolysis technique with cerium nitrate salt, Ce(NO 3 ) 3 ·6H 2 O as precursor. Fluorine doped cadmium oxide (CdO:F) thin film prepared using spray pyrolysis technique acts as the TCO film and hence the bare electrode. The structural, morphological and elemental characterizations of the films were carried out using X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and energy dispersive X-ray analysis (EDX) respectively. The diffraction peak positions in XRD confirmed the formation of highly crystalline ceria with cubic structure and FE-SEM images showed uniform adherent films with granular morphology. The band gaps of CeO 2 and TCO were found to be 3.2 eV and 2.6 eV respectively. Lipase enzyme was physisorbed on the surface of CeO 2 /TCO film to form the lipase/nano-CeO 2 /TCO bioelectrode. Sensing studies were carried out using cyclic voltammetry and amperometry, with lipase/nano-CeO 2 /TCO as working electrode and tributyrin as substrate. The mediator-free biosensor with nanointerface exhibited excellent linearity (0.33–1.98 mM) with a lowest detection limit of 2 μM with sharp response time of 5 s and a shelf life of about 6 weeks. -- Graphical abstract: Nanostructured cerium oxide thin films were deposited on transparent conducting oxide (TCO) substrate using spray pyrolysis technique. Fluorine doped cadmium oxide (CdO:F) thin film acts as the TCO film and hence the working electrode. Lipase enzyme was physisorbed on the surface of CeO 2 /TCO film and hence the lipase/nano-CeO 2 /TCO bioelectrode has been fabricated. Sensing studies were carried out using cyclic voltammetry and amperometry with tributyrin as substrate. The mediator-free biosensor with nanointerface exhibited excellent linearity (0.33–1.98 mM) with a lowest detection limit of 2 μM with sharp response time of 5 s and a shelf life of about 6

The Preparation and Property of Graphene /Tin Oxide Transparent Conductive Film

Directory of Open Access Journals (Sweden)

SUN Tao

2017-02-01

Full Text Available Graphene doped tin oxide composites were prepared with SnCIZ·2HZ 0 and graphene oxide as raw materials with sol-gel method and then spincoated on the quartz glass to manufacture a new transparent conductive film. The composite film was characterized with X-ray diffraction(XRDand scanning electron microscopy(SEM analysis. XRD results show that the graphene oxide was successfully prepared with Hummers method. The graphene layers and particulate SnOZ can be clearly observed in SEM photos. The transmittance and conductivity of the thin films were tested with ultraviolet visible spectrophotometer and Hall effect measurement. The results show that the transmittivity of composite film in visible region is more than 90% and surface square resistance is 41 S2/口.The graphene/ SnOZ film exhibits a higher performance in transparence and conductivity than commercial FTO glass.

Oxide films in laser additive manufactured Inconel 718

International Nuclear Information System (INIS)

Zhang, Y.N.; Cao, X.; Wanjara, P.; Medraj, M.

2013-01-01

A continuous-wave 5 kW fiber laser welding system was used in conduction mode to deposit Inconel® alloy 718 (IN718) by employing filler wire on as-serviced IN718 parent material (PM) substrates. The direct laser deposited (DLD) coupons and as-serviced IN718 PM were then evaluated through tensile testing. To understand the failure mechanisms, the tensile fracture surfaces of the as-serviced IN718 PM, DLD and DLD-PM samples were analyzed using scanning electron microscopy. The fracture surfaces revealed the presence of both Al 2 O 3 and Cr 2 O 3 films, although the latter was reasoned to be the main oxide in IN718. Both the experimental observations and thermodynamic analysis indicated that oxidation of some alloying elements in IN718 cannot be completely avoided during manufacturing, whether in the liquid state under vacuum (for casting, the electron beam melting, welding and/or deposition) or with inert gas protection (for welding or laser deposition). The exposed surface of the oxide film on the fracture surface has poor wetting with the metal and thus can constitute a lack of bonding or a crack with either the metal and/or another non-wetted side of the oxide film. On the other hand, the wetted face of the oxide film has good atom-to-atom contact with the metal and may nucleate some intermetallic compounds, such as Laves, Ni 3 Nb-δ, Nb-rich MC and γ′ compounds. The potential of their nucleation on Cr 2 O 3 was assessed using planar disregistry. Coherent planes were found between these intermetallics and Cr 2 O 3

Copper oxide thin films anchored on glass substrate by sol gel spin coating technique

Science.gov (United States)

Krishnaprabha, M.; Venu, M. Parvathy; Pattabi, Manjunatha

2018-05-01

Owing to the excellent optical, thermal, electrical and photocatalytic properties, copper oxide nanoparticles/films have found applications in optoelectronic devices like solar/photovoltaic cells, lithium ion batteries, gas sensors, catalysts, magnetic storage media etc. Copper oxide is a p-type semiconductor material having a band gap energy varying from 1.2 eV-2.1 eV. Syzygium Samarangense fruit extract was used as reducing agent to synthesize copper oxide nanostructures at room temperature from 10 mM copper sulphate pentahydrate solution. The synthesized nanostructures are deposited onto glass substrate by spin coating followed by annealing the film at 200 °C. Both the copper oxide colloid and films are characterized using UV-Vis spectroscopy, field emission scanning electron microscopy (FESEM) and energy dispersive spectroscopy (EDS) techniques. Presence of 2 peaks at 500 nm and a broad peak centered around 800 nm in the UV-Vis absorbance spectra of copper oxide colloid/films is indicative of the formation of anisotropic copper oxide nanostructures is confirmed by the FESEM images which showed the presence of triangular shaped and rod shaped particles. The rod shaped particles inside island like structures were found in unannealed films whereas the annealed films contained different shaped particles with reduced sizes. The elemental analysis using EDS spectra of copper oxide nanoparticles/films showed the presence of both copper and oxygen. Electrical properties of copper oxide nanoparticles are affected due to quantum size effect. The electrical studies carried out on both unannealed and annealed copper oxide films revealed an increase in resistivity with annealing of the films.

Structural transformation of nickel hydroxide films during anodic oxidation

Energy Technology Data Exchange (ETDEWEB)

Crocker, Robert W. [Univ. of California, Berkeley, CA (United States); Muller, Rolf H. [Univ. of California, Berkeley, CA (United States)

1992-05-01

The transformation of anodically formed nickel hydroxide/oxy-hydroxide electrodes has been investigated. A mechanism is proposed for the anodic oxidation reaction, in which the reaction interface between the reduced and oxidized phases of the electrode evolves in a nodular topography that leads to inefficient utilization of the active electrode material. In the proposed nodular transformation model for the anodic oxidation reaction, nickel hydroxide is oxidized to nickel oxy-hydroxide in the region near the metal substrate. Since the nickel oxy-hydroxide is considerably more conductive than the surrounding nickel hydroxide, as further oxidation occurs, nodular features grow rapidly to the film/electrolyte interface. Upon emerging at the electrolyte interface, the reaction boundary between the nickel hydroxide and oxy-hydroxide phases spreads laterally across the film/electrolyte interface, creating an overlayer of nickel oxy-hydroxide and trapping uncharged regions of nickel hydroxide within the film. The nickel oxy-hydroxide overlayer surface facilitates the oxygen evolution side reaction. Scanning tunneling microscopy of the electrode in its charged state revealed evidence of 80 - 100 Angstrom nickel oxy-hydroxide nodules in the nickel hydroxide film. In situ spectroscopic ellipsometer measurements of films held at various constant potentials agree quantitatively with optical models appropriate to the nodular growth and subsequent overgrowth of the nickel oxy-hydroxide phase. A two-dimensional, numerical finite difference model was developed to simulate the current distribution along the phase boundary between the charged and uncharged material. The model was used to explore the effects of the physical parameters that govern the electrode behavior. The ratio of the conductivities of the nickel hydroxide and oxy-hydroxide phases was found to be the dominant parameter in the system.

Structural transformation of nickel hydroxide films during anodic oxidation

Energy Technology Data Exchange (ETDEWEB)

Crocker, R.W.; Muller, R.H.

1992-05-01

The transformation of anodically formed nickel hydroxide/oxy-hydroxide electrodes has been investigated. A mechanism is proposed for the anodic oxidation reaction, in which the reaction interface between the reduced and oxidized phases of the electrode evolves in a nodular topography that leads to inefficient utilization of the active electrode material. In the proposed nodular transformation model for the anodic oxidation reaction, nickel hydroxide is oxidized to nickel oxy-hydroxide in the region near the metal substrate. Since the nickel oxy-hydroxide is considerably more conductive than the surrounding nickel hydroxide, as further oxidation occurs, nodular features grow rapidly to the film/electrolyte interface. Upon emerging at the electrolyte interface, the reaction boundary between the nickel hydroxide and oxy-hydroxide phases spreads laterally across the film/electrolyte interface, creating an overlayer of nickel oxy-hydroxide and trapping uncharged regions of nickel hydroxide within the film. The nickel oxy-hydroxide overlayer surface facilitates the oxygen evolution side reaction. Scanning tunneling microscopy of the electrode in its charged state revealed evidence of 80 {endash} 100 Angstrom nickel oxy-hydroxide nodules in the nickel hydroxide film. In situ spectroscopic ellipsometer measurements of films held at various constant potentials agree quantitatively with optical models appropriate to the nodular growth and subsequent overgrowth of the nickel oxy-hydroxide phase. A two-dimensional, numerical finite difference model was developed to simulate the current distribution along the phase boundary between the charged and uncharged material. The model was used to explore the effects of the physical parameters that govern the electrode behavior. The ratio of the conductivities of the nickel hydroxide and oxy-hydroxide phases was found to be the dominant parameter in the system.

Biomass as biosorbent for molybdenum ions

International Nuclear Information System (INIS)

Yamaura, Mitiko; Santos, Jacinete L. dos; Damasceno, Marcos O.; Egute, Nayara dos S.; Moraes, Adeniane A.N.; Santos, Bruno Z.

2013-01-01

Biosorbents have been focused as renewable materials of low cost, and have been used for metal removal from the wastewater by adsorption phenomenon. Biosorbents are prepared of biomass, whose reactive sites in its chemical structure have affinity to bind to metal ions. In this work, performance of corn husk, sugarcane bagasse, coir, banana peel, fish scale, chitin and chitosan as biosorbents of molybdenum (VI) ions in aqueous medium was evaluated. The adsorption experiments were investigated in a batch system varying the pH solution from 0.5 to 12 and the contact time between the phases from 2 min to 70 min. 99 Mo radioisotope was used as radioactive tracer for analysis of molybdenum ions by gamma spectroscopy using a HPGe detector. Results revealed that acidity of the solution favored the adsorption of Mo (VI) ions on the all biosorbents. Adsorption values higher than 85% were found on sugarcane bagasse, coir, corn husk, chitin and chitosan at pH 2.0. Only the chitosan was dissolved at pH 0.5 and a gel was formed. The models of pseudo-second order and external film diffusion described the kinetics of adsorption of Mo ions on the coir. This work showed that the studied biomass has high potential to be used as biosorbent of molybdenum ions from acidic wastewater, and the kinetics of Mo adsorption on the coir suggested high-affinity adsorption governed by chemisorption. (author)

Biomass as biosorbent for molybdenum ions

Energy Technology Data Exchange (ETDEWEB)

Yamaura, Mitiko; Santos, Jacinete L. dos; Damasceno, Marcos O.; Egute, Nayara dos S.; Moraes, Adeniane A.N.; Santos, Bruno Z., E-mail: myamaura@ipen.br, E-mail: jlsantos@ipen.br, E-mail: molidam@ipen.br, E-mail: nayara.egute@usp.br, E-mail: adenianemrs@ig.com.br, E-mail: bzsantos@gmail.com [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2013-07-01

Biosorbents have been focused as renewable materials of low cost, and have been used for metal removal from the wastewater by adsorption phenomenon. Biosorbents are prepared of biomass, whose reactive sites in its chemical structure have affinity to bind to metal ions. In this work, performance of corn husk, sugarcane bagasse, coir, banana peel, fish scale, chitin and chitosan as biosorbents of molybdenum (VI) ions in aqueous medium was evaluated. The adsorption experiments were investigated in a batch system varying the pH solution from 0.5 to 12 and the contact time between the phases from 2 min to 70 min. {sup 99}Mo radioisotope was used as radioactive tracer for analysis of molybdenum ions by gamma spectroscopy using a HPGe detector. Results revealed that acidity of the solution favored the adsorption of Mo (VI) ions on the all biosorbents. Adsorption values higher than 85% were found on sugarcane bagasse, coir, corn husk, chitin and chitosan at pH 2.0. Only the chitosan was dissolved at pH 0.5 and a gel was formed. The models of pseudo-second order and external film diffusion described the kinetics of adsorption of Mo ions on the coir. This work showed that the studied biomass has high potential to be used as biosorbent of molybdenum ions from acidic wastewater, and the kinetics of Mo adsorption on the coir suggested high-affinity adsorption governed by chemisorption. (author)

Ion beam analysis of PECVD silicon oxide thin films

International Nuclear Information System (INIS)

Fernandez-Lima, F.; Rodriguez, J.A.; Pedrero, E.; Fonseca Filho, H.D.; Llovera, A.; Riera, M.; Dominguez, C.; Behar, M.; Zawislak, F.C.

2006-01-01

A study of ion beam analysis techniques of plasma enhanced chemical vapor deposited (PECVD) silicon oxide thin films (1 μm thick) obtained from silane (SiH 4 ) and nitrous oxide (N 2 O) is reported. The film, elemental composition and surface morphology were determined as function of the reactant gas flow ratio, R = [N 2 O]/[SiH 4 ] in the 22-110 range using the Rutherford backscattering spectrometry, nuclear reaction analysis and atomic force microscopy techniques. The density of the films was determined by combining the RBS and thickness measurements. All the experiments were done at a deposition temperature of 300 deg. C. In all the cases almost stoichiometric oxides were obtained being the impurity content function of R. It was also observed that physical properties such as density, surface roughness and shape factor increase with R in the studied interval

Micro-length anodic porous niobium oxide for lithium-ion thin film battery applications

International Nuclear Information System (INIS)

Yoo, Jeong Eun; Park, Jiyoung; Cha, Gihoon; Choi, Jinsub

2013-01-01

The anodization of niobium in an aqueous mixture of H 3 PO 4 and HF in the potential range from 2.5 to 30 V for 2 h at 5 °C was performed, demonstrating that anodic porous niobium oxide film with a thickness of up to 2000 nm, including a surface dissolution layer, can be obtained by controlling the applied potential and composition of the electrolytes. Specifically, surface dissolution-free porous niobium oxide film with a thickness of 800 nm can be prepared in a low electrolyte concentration. The surface dissolution is observed when the concentration ratio of HF (wt.%):H 3 PO 4 (M) was more than 2:1. The discontinuous layers in the niobium oxide film were observed when the thickness was higher than 500 nm, which was ascribed to the large volume expansion of the niobium oxide grown from the niobium metal. The anodic porous niobium oxide film was used as the cathode for lithium-ion batteries in the potential range from 1.2 to 3.0 V at a current density of 7.28 × 10 − 6 A cm −2 . The first discharge capacity of ca. 53 μA h cm − 2 was obtained in 800 nm thick niobium oxide without a surface dissolution layer. - Highlights: ► Anodic porous niobium oxide film with a thickness of 2000 nm was obtained. ► Surface dissolution-free porous niobium oxide film was prepared. ► The niobium oxide film was used as the cathode for lithium-ion batteries

Investigation of molybdenum-crosslinker interfaces for affinity based electrochemical biosensing applications

Science.gov (United States)

Kamakoti, Vikramshankar; Shanmugam, Nandhinee Radha; Tanak, Ambalika Sanjeev; Jagannath, Badrinath; Prasad, Shalini

2018-04-01

Molybdenum (Mo) has been investigated for implementation as an electrode material for affinity based biosensing towards devloping flexibe electronic biosensors. Treatment of the native oxide of molybdenum was investigated through two surface treatment strategies namely thiol and carbodiimide crosslinking methods. The binding interaction between cross-linker molecules and Mo electrode surface has been characterized using Fourier Transform Infrared Spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and optical microscopy. The efficacy of treatment of Mo with its native oxide using carbodiimide cross linking methodology was established. The carbodiimide cross-linking chemistry was found to possess better surface coverage and binding affinity with Molybdenum electrode surface when compared to thiol cross-linking chemistry.Electrochemical characterization of Mo electrode using Electrochemical Impedance Spectroscopy (EIS) and Cyclic Voltametry (CV) techniques was performed to evaluate the effect of ionic properties of solution buffer on the Mo electrode's performance. Affinity based biosensing of C-Reactive Protein (CRP) has been demonstrated on a flexible nanoporous polymeric substrate with detection threshold of 100 pg/ml in synthetic urine buffer medium. The biosensor has been evaluated to be developed as a dipstick based point of care device for detection of biomarkers in urine.

Preparation and characterization of vanadium oxide thin films

Energy Technology Data Exchange (ETDEWEB)

Monfort, O.; Plesch, G. [Comenius University of Bratislava, Faculty of Natural Sciences, Department of Inorganic Chemistry, 84215 Bratislava (Slovakia); Roch, T. [Comenius University of Bratislava, Faculty of Mathematics Physics and Informatics, Department of Experimental Physics, 84248 Bratislava (Slovakia)

2013-04-16

The thermotropic VO{sub 2} films have many applications, since they exhibit semiconductor-conductor switching properties at temperature around 70 grad C. Vanadium oxide thin films were prepared via sol-gel method. Spin coater was used to depose these films on Si/SiO{sub 2} and lime glass substrates. Thin films of V{sub 2}O{sub 5} can be reduced to metastable VO{sub 2} thin films at the temperature of 450 grad C under the pressure of 10{sup -2} Pa. These films are then converted to thermotropic VO{sub 2} at 700 grad C in argon under normal pressure. (authors)

Hybrid dextran-iron oxide thin films deposited by laser techniques for biomedical applications

International Nuclear Information System (INIS)

Predoi, D.; Ciobanu, C.S.; Radu, M.; Costache, M.; Dinischiotu, A.; Popescu, C.; Axente, E.; Mihailescu, I.N.; Gyorgy, E.

2012-01-01

Iron oxide nanoparticles were prepared by chemical co-precipitation method. The nanoparticles were mixed with dextran in distilled water. The obtained solutions were frozen in liquid nitrogen and used as targets during matrix assisted pulsed laser evaporation for the growth of hybrid, iron oxide nanoparticles-dextran thin films. Fourier Transform Infrared Spectroscopy and X-ray diffraction investigations revealed that the obtained films preserve the structure and composition of the initial, non-irradiated iron oxide-dextran composite material. The biocompatibility of the iron oxide-dextran thin films was demonstrated by 3-(4.5 dimethylthiazol-2yl)-2.5-diphenyltetrazolium bromide-based colorimetric assay, using human liver hepatocellular carcinoma cells. - Highlights: ► Hybrid, dextran-iron oxide nanoparticles and thin films. ► Laser immobilization. ► Biocompatibility of dextran-iron oxide nanoparticles.

Investigation of structural, morphological and electrical properties of APCVD vanadium oxide thin films

International Nuclear Information System (INIS)

Papadimitropoulos, Georgios; Trantalidis, Stelios; Tsiatouras, Athanasios; Vasilopoulou, Maria; Davazoglou, Dimitrios; Kostis, Ioannis

2015-01-01

Vanadium oxide films were chemically vapor deposited (CVD) on oxidized Si substrates covered with CVD tungsten (W) thin films and on glass substrates covered with indium tin oxide (ITO) films, using vanadium(V) oxy-tri-isopropoxide (C 9 H 21 O 4 V) vapors. X-ray diffraction (XRD) measurements showed that the deposited films were composed of a mixture of vanadium oxides; the composition was determined mainly by the deposition temperature and less by the precursor temperature. At temperatures up to 450 C the films were mostly composed by monoclinic VO 2 . Other peaks corresponding to various vanadium oxides were also observed. X-ray microanalysis confirmed the composition of the films. The surface morphology was studied with atomic force microscopy (AFM) and scanning electron microscopy (SEM). These measurements revealed that the morphology strongly depends on the used substrate and the deposition conditions. The well-known metal-insulator transition was observed near 75 C for films mostly composed by monoclinic VO 2 . Films deposited at 450 C exhibited two transitions one near 50 C and the other near 60 C possibly related to the presence of other vanadium phases or of important stresses in them. Finally, the vanadium oxide thin films exhibited significant sensory capabilities decreasing their resistance in the presence of hydrogen gas with response times in the order of a few seconds and working temperature at 40 C. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

The growth and evolution of thin oxide films on delta-plutonium surfaces

Energy Technology Data Exchange (ETDEWEB)

Garcia Flores, Harry G [Los Alamos National Laboratory; Pugmire, David L [Los Alamos National Laboratory

2009-01-01

The common oxides of plutonium are the dioxide (PuO{sub 2}) and the sesquioxide (Pu{sub 2}O{sub 3}). The structure of an oxide on plutonium metal under air at room temperature is typically described as a thick PuO{sub 2} film at the gas-oxide interface with a thinner PuO{sub 2} film near the oxide-metal substrate interface. In a reducing environment, such as ultra high vacuum, the dioxide (Pu{sup 4+}; O/Pu = 2.0) readily converts to the sesquioxide (Pu{sup 3+}; O/Pu = 1.5) with time. In this work, the growth and evolution of thin plutonium oxide films is studied with x-ray photoelectron spectroscopy (XPS) under varying conditions. The results indicate that, like the dioxide, the sesquioxide is not stable on a very clean metal substrate under reducing conditions, resulting in substoichiometric films (Pu{sub 2}O{sub 3-y}). The Pu{sub 2}O{sub 3-y} films prepared exhibit a variety of stoichiometries (y = 0.2-1) as a function of preparation conditions, highlighting the fact that caution must be exercised when studying plutonium oxide surfaces under these conditions and interpreting resulting data.

Cuprous oxide thin films grown by hydrothermal electrochemical deposition technique

International Nuclear Information System (INIS)

Majumder, M.; Biswas, I.; Pujaru, S.; Chakraborty, A.K.

2015-01-01

Semiconducting cuprous oxide films were grown by a hydrothermal electro-deposition technique on metal (Cu) and glass (ITO) substrates between 60 °C and 100 °C. X-ray diffraction studies reveal the formation of cubic cuprous oxide films in different preferred orientations depending upon the deposition technique used. Film growth, uniformity, grain size, optical band gap and photoelectrochemical response were found to improve in the hydrothermal electrochemical deposition technique. - Highlights: • Cu 2 O thin films were grown on Cu and glass substrates. • Conventional and hydrothermal electrochemical deposition techniques were used. • Hydrothermal electrochemical growth showed improved morphology, thickness and optical band gap

Extraction and selective stripping of uranium and molybdenum in sulfate solution using amines

International Nuclear Information System (INIS)

Sialino, E.; Mignot, C.; Michel, P.; Vial, J.

1977-01-01

The uranium solutions issued from leaching of AKOUTA ores and containing lot of molybdenum are purified using solvent extraction. During the first test run precipitation of complexes such as amine phosphomolybdate was observed. It was pointed out that the precipitation could be prevented if the molybdenum is oxidized in the feed prior to solvent extraction. Informations on the basic studies carried out to ensure the reliability of the process are given in the complete paper

Effect of micro-patterned fluorine-doped tin oxide films on electrochromic properties of Prussian blue films

Energy Technology Data Exchange (ETDEWEB)

Lee, Kyuha [Center for Energy Convergence Research, Green City Technology Institute, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Kim, A-Young [Center for Energy Convergence Research, Green City Technology Institute, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Department of Material Science and Engineering, Korea University, Seoul 136-701 (Korea, Republic of); Park, Ji Hun; Jung, Hun-Gi; Choi, Wonchang; Lee, Hwa Young [Center for Energy Convergence Research, Green City Technology Institute, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Lee, Joong Kee, E-mail: leejk@kist.re.kr [Center for Energy Convergence Research, Green City Technology Institute, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791 (Korea, Republic of)

2014-09-15

Graphical abstract: - Highlights: • PB-based ECD employed micro-patterned FTO electrode was fabricated. • Effect of interface morphology on electrochromic characteristics was examined. • Electrochromic properties were enhanced by employing a patterned interface. - Abstract: The effect of interface morphology on electrochromic characteristics was examined for an electrochromic device (ECD). Micro-patterned fluorine-doped tin oxide (FTO) films were fabricated using a photolithography process. Prussian blue (PB) films were then deposited on the patterned FTO films. The surface areas of both PB films and FTO films were increased by patterning. ECDs were assembled using patterned PB/FTO films as the electrochromic electrode, bare FTO films as the counter electrode, and an electrolyte containing LiClO{sub 4} salt. The increased effective surface area of the patterned PB/FTO electrode boosted the mobility of ions at the interphase between the electrolyte and PB electrode, and the electron transfer between PB films and FTO films. As a result, electrochromic properties such as transmittance and response time were significantly improved by employing the patterned FTO films as the transparent conductive oxide layer of the electrochromic electrode.

Room-temperature Synthesis of Amorphous Molybdenum Oxide Nanodots with Tunable Localized Surface Plasmon Resonances.

Science.gov (United States)

Zhu, Chuanhui; Xu, Qun; Ji, Liang; Ren, Yumei; Fang, Mingming

2017-12-05

Two-dimensional (2D) semiconductors have recently emerged as a remarkable class of plasmonic alternative to conventional noble metals. However, tuning of their plasmonic resonances towards different wavelengths in the visible-light region with physical or chemical methods still remains challenging. In this work, we design a simple room-temperature chemical reaction route to synthesize amorphous molybdenum oxide (MoO 3-x ) nanodots that exhibit strong localized surface plasmon resonances (LSPR) in the visible and near-infrared region. Moreover, tunable plasmon resonances can be achieved in a wide range with the changing surrounding solvent, and accordingly the photoelectrocatalytic activity can be optimized with the varying LSPR peaks. This work boosts the light-matter interaction at the nanoscale and could enable photodetectors, sensors, and photovoltaic devices in the future. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Air-segmented continuous-flow analysis for molybdenum in various geochemical samples

International Nuclear Information System (INIS)

Harita, Y.; Sugiyama, M.; Hori, T.

2003-01-01

An air-segmented continuous-flow method has been developed for the determination of molybdenum at ultra trace levels using the catalytic effect of molybdate during the oxidation of L-ascorbic acid by hydrogen peroxide. Incorporation of an on-line ion exchange column improved the tolerance limit for various ions. The detection limits with and without the column were 64 pmol L m1 and 17 pmol L m1 , and the reproducibilities at 10 nmol L m1 were 2.1 % and 0.2 %, respectively. The proposed method was applied to the determination of molybdenum in seawater and lake water as well as in rock and sediment samples. This method has the highest sensitivity among the available literature to our knowledge, and is also convenient for routine analysis of molybdenum in various natural samples. (author)

Growth and etching characteristics of gallium oxide thin films by pulsed laser deposition

International Nuclear Information System (INIS)

Ou, Sin-Liang; Wuu, Dong-Sing; Fu, Yu-Chuan; Liu, Shu-Ping; Horng, Ray-Hua; Liu, Lei; Feng, Zhe-Chuan

2012-01-01

Highlights: ► The β-Ga2O3 thin films are prepared by pulsed laser deposition. ► The substrate temperature affects the structural, optical and etching properties of the grown films. ► The optical transmittance and band gap of the films increased with increasing the substrate temperature. ► The etching treatments for gallium oxide are performed in 49 mol% HF solution at room temperature. ► The gallium oxide thin film grown at 400 °C has the highest etching rate of 490 nm s −1 . - Abstract: The gallium oxide films were deposited on (0 0 1) sapphire at various substrate temperatures from 400 to 1000 °C by pulsed laser deposition using a KrF excimer laser. The etching treatments for as-grown gallium oxide were performed in a 49 mol% HF solution at room temperature. The structural, optical and etching properties of the grown films were investigated in terms of high resolution X-ray diffraction, optical transmittance, atomic force microscopy, and X-ray photoelectron spectroscopy. The phase transition from amorphous to polycrystalline β-Ga 2 O 3 structure was observed with increasing growth temperature. From the optical transmittance measurements, the films grown at 550–1000 °C exhibit a clear absorption edge at deep ultraviolet region around 250–275 nm wavelength. It was found that the optical band gap of gallium oxide films increased from 4.56 to 4.87 eV when the substrate temperature increased from 400 to 1000 °C. As the substrate temperature increases, the crystallinity of gallium oxide film is enhanced and the etching rate is decreased. The high etching rate of 490 nm s −1 for gallium oxide film grown at 400 °C could be due to its amorphous phase, which is referred to higher void ratio and looser atomic structure.

Copper:molybdenum sub-oxide blend as transparent conductive electrode (TCE) indium free

Science.gov (United States)

Hssein, Mehdi; Cattin, Linda; Morsli, Mustapha; Addou, Mohammed; Bernède, Jean-Christian

2016-05-01

Oxide/metal/oxide structures have been shown to be promising alternatives to ITO. In such structures, in order to decrease the high light reflection of the metal film it is embedded between two metal oxides dielectric. MoO3-x is often used as oxide due to its capacity to be a performing anode buffer layer in organic solar cells, while silver is the metal the most often used [1]. Some attempts to use cheaper metal such as copper have been done. However it was shown that Cu diffuses strongly into MoO3-x [2]. Here we used this property to grow simple new transparent conductive oxide (TCE), i.e., Cu: MoO3-x blend. After the deposition of a thin Cu layer, a film of MoO3-x is deposited by sublimation. An XPS study shows more than 50% of Cu is present at the surface of the structure. In order to limit the Cu diffusion an ultra-thin Al layer is deposited onto MoO3-x. Then, in order to obtain a good hole collecting contact with the electron donor of the organic solar cells, a second MoO3-x layer is deposited. After optimization of the thickness of the different layers, the optimum structure is as follow: Cu (12 nm) : MoO3-x (20 nm)/Al (0.5 nm)/ MoO3-x (10 nm). The sheet resistance of this structure is Rsq = 5.2 Ω/sq. and its transmittance is Tmax = 65%. The factor of merit ϕM = T10/Rsq. = 2.41 × 10-3 Ω-1, which made this new TCE promising as anode in organic solar cells. Contribution to the topical issue "Materials for Energy Harvesting, Conversion and Storage (ICOME 2015) - Elected submissions", edited by Jean-Michel Nunzi, Rachid Bennacer and Mohammed El Ganaoui

Remote plasma-enhanced metalorganic chemical vapor deposition of aluminum oxide thin films

NARCIS (Netherlands)

Volintiru, I.; Creatore, M.; Hemmen, van J.L.; Sanden, van de M.C.M.

2008-01-01

Aluminum oxide films were deposited using remote plasma-enhanced metalorganic chemical vapor deposition from oxygen/trimethylaluminum mixtures. Initial studies by in situ spectroscopic ellipsometry demonstrated that the aluminum oxide films deposited at temperatures

Preparation and characterization of molybdenum disilicide coating on molybdenum substrate by air plasma spraying

International Nuclear Information System (INIS)

Wang, Yi; Wang, Dezhi; Yan, Jianhui; Sun, Aokui

2013-01-01

MoSi 2 oxidation protective coatings on molybdenum substrate were prepared by air plasma spraying technique (APS). Microstructure, phase composition, porosity, microhardness and bonding strength of the coatings were investigated and determined. Oxidation behavior of the coating at high temperature was also examined. Results show that composition of the coatings is constituted with MoSi 2 and Mo 5 Si 3 , the surface morphology is described as flattened lamellar features, insufficiently flattened protuberance with some degree of surface roughness, a certain quantity of spherical particles, microcracks and pores. Testing results reveal that microhardness and bonding strength of the coatings increase, and porosity decreases with increasing power or decreasing Ar gas flow rate. Moreover, with decreasing the porosity, the microhardness of the coatings increases. The bonding strength of the coatings also increases with increasing spray distance. The MoSi 2 coated Mo substrate exhibited a good oxidation resistance at 1200 °C.

Ion beam-based characterization of multicomponent oxide thin films and thin film layered structures

International Nuclear Information System (INIS)

Krauss, A.R.; Rangaswamy, M.; Lin, Yuping; Gruen, D.M.; Schultz, J.A.; Schmidt, H.K.; Chang, R.P.H.

1992-01-01

Fabrication of thin film layered structures of multi-component materials such as high temperature superconductors, ferroelectric and electro-optic materials, and alloy semiconductors, and the development of hybrid materials requires understanding of film growth and interface properties. For High Temperature Superconductors, the superconducting coherence length is extremely short (5--15 Angstrom), and fabrication of reliable devices will require control of film properties at extremely sharp interfaces; it will be necessary to verify the integrity of thin layers and layered structure devices over thicknesses comparable to the atomic layer spacing. Analytical techniques which probe the first 1--2 atomic layers are therefore necessary for in-situ characterization of relevant thin film growth processes. However, most surface-analytical techniques are sensitive to a region within 10--40 Angstrom of the surface and are physically incompatible with thin film deposition and are typically restricted to ultra high vacuum conditions. A review of ion beam-based analytical methods for the characterization of thin film and multi-layered thin film structures incorporating layers of multicomponent oxides is presented. Particular attention will be paid to the use of time-of-flight techniques based on the use of 1- 15 key ion beams which show potential for use as nondestructive, real-time, in-situ surface diagnostics for the growth of multicomponent metal and metal oxide thin films

Study of heterogeneous catalytic processes over cobalt, molybdenum and cobalt-molybdenum catalysts supported on alumina by temperature-programmed desorption and temperature-programmed reaction. 1. Adsorption of hydrozen

International Nuclear Information System (INIS)

Rozanov, V.V.; Tsao Yamin; Krylov, O.V.

1996-01-01

Hydrogen adsorption on reduced, sulphidized and reoxidized specimens of molybdenum-and cobalt-molybdenum-containing catalysts applied on aluminium oxide has been studied by the method of thermal desorption (TD). Comparison of TD spectra of hydrogen and data of X-ray phase analysis of the specimens and mass-spectrometric analysis of the products desorbed from the surface of catalysts after their successive reduction sulphidizing, carbonizing and reoxidation permitted a correlation between various forms of hydrogen adsorption and certain centres on the surface of the catalysts. 12 refs., 2 figs

Hybrid dextran-iron oxide thin films deposited by laser techniques for biomedical applications

Energy Technology Data Exchange (ETDEWEB)

Predoi, D.; Ciobanu, C.S. [National Institute for Physics of Materials, P.O. Box MG 07, Bucharest, Magurele (Romania); Radu, M.; Costache, M.; Dinischiotu, A. [Molecular Biology Center, University of Bucharest, 91-95 Splaiul Independentei, 76201, Bucharest 5 (Romania); Popescu, C.; Axente, E.; Mihailescu, I.N. [National Institute for Lasers, Plasma and Radiations Physics, P. O. Box MG 36, 77125 Bucharest (Romania); Gyorgy, E., E-mail: egyorgy@cin2.es [National Institute for Lasers, Plasma and Radiations Physics, P. O. Box MG 36, 77125 Bucharest (Romania); Consejo Superior de Investigaciones Cientificas, Centre d' Investigacions en Nanociencia i Nanotecnologia (CSIC-CIN2), Campus UAB, 08193 Bellaterra (Spain)

2012-02-01

Iron oxide nanoparticles were prepared by chemical co-precipitation method. The nanoparticles were mixed with dextran in distilled water. The obtained solutions were frozen in liquid nitrogen and used as targets during matrix assisted pulsed laser evaporation for the growth of hybrid, iron oxide nanoparticles-dextran thin films. Fourier Transform Infrared Spectroscopy and X-ray diffraction investigations revealed that the obtained films preserve the structure and composition of the initial, non-irradiated iron oxide-dextran composite material. The biocompatibility of the iron oxide-dextran thin films was demonstrated by 3-(4.5 dimethylthiazol-2yl)-2.5-diphenyltetrazolium bromide-based colorimetric assay, using human liver hepatocellular carcinoma cells. - Highlights: Black-Right-Pointing-Pointer Hybrid, dextran-iron oxide nanoparticles and thin films. Black-Right-Pointing-Pointer Laser immobilization. Black-Right-Pointing-Pointer Biocompatibility of dextran-iron oxide nanoparticles.

Elucidation of the electrochromic mechanism of nanostructured iron oxides films

Energy Technology Data Exchange (ETDEWEB)

Garcia-Lobato, M.A.; Martinez, Arturo I.; Castro-Roman, M. [Center for Research and Advanced Studies of the National Polytechnic Institute, Cinvestav Campus Saltillo, Carr. Saltillo-Monterrey Km. 13, Ramos Arizpe, Coah. 25900 (Mexico); Perry, Dale L. [Mail Stop 70A1150, Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720 (United States); Zarate, R.A. [Departamento de Fisica, Facultad de Ciencias, Universidad Catolica del Norte, Casilla 1280, Antofagasta (Chile); Escobar-Alarcon, L. (Departamento de Fisica, Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico)

2011-02-15

Nanostructured hematite thin films were electrochemically cycled in an aqueous solution of LiOH. Through optical, structural, morphological, and magnetic measurements, the coloration mechanism of electrochromic iron oxide thin films was elucidated. The conditions for double or single electrochromic behavior are given in this work. During the electrochemical cycling, it was found that topotactic transformations of hexagonal crystal structures are favored; i.e. {alpha}-Fe{sub 2}O{sub 3} to Fe(OH){sub 2} and subsequently to {delta}-FeOOH. These topotactic redox reactions are responsible for color changes of iron oxide films. (author)

Optimum deposition, structure, and properties of tantalum oxide films

International Nuclear Information System (INIS)

Lin, Y.C.

1985-01-01

Amorphous, ductile, and uniform Ta 2 O 5 films that acted as diffusion barriers were developed by sputter depositing Ta metal on Al single crystals (99.99%) and subsequently anodizing these thin films. The morphology, microstructure, composition and properties were characterized by scanning and transmission electron microscopy, surface and Fourier transform infrared spectroscopy, X-ray diffraction, and fluorescence. Superior corrosion resistance in a water saturated Cl 2 atmosphere was provided by Ta 2 O 5 coating on Al single crystal substrates but not on Al alloys. The strong Ta-O bond, the non-porous nature of the film and good adhesion to the substrate are attributed to the outstanding corrosion resistance of these oxide coatings. Al alloy surfaces are not protected, since the anodic film formed over grain boundaries, processing lines and emergent precipitates is poorly adherent, thus providing loci for corrosion. These problems were eliminated by casting a 400 A layer of tantalum oxyhydroxide polymer from ethanol solution onto Al substrate and curing to a Ta 2 O 5 layer that effectively resisted attack by wet Cl 2 . The mechanical properties of Ta 2 O 5 films on Al alloys were studied at various pH's by in-situ fatigue loading coupled with electrochemical measurements of corrosion potential and corrosion current. These results indicate the fatigue resistance of this oxide film effectively protects the underlying metal from strong HCl solution attack. The very unusual ductility and high corrosion resistance of Ta 2 O 5 films could be related to the graphite-like structure that exists in the amorphous state of this oxide

Improve the conversion efficiency of Cu{sub 2}ZnSnSe{sub 4} solar cells using a novel molybdenum back contact structure

Energy Technology Data Exchange (ETDEWEB)

Sun, Ding [Institute of Photo Electronics thin Film Devices and Technology of Nankai University, Key Laboratory of Photoelectronic Thin Film Devices and Technology, Tianjin 300071 (China); School of Electrical and Computer Engineering, Jilin Jianzhu University, Changchun 130118 (China); Xu, Shengzhi; Zhang, Li; Wei, Changchun [Institute of Photo Electronics thin Film Devices and Technology of Nankai University, Key Laboratory of Photoelectronic Thin Film Devices and Technology, Tianjin 300071 (China); Li, Yuli; Chi, Yaodan [School of Electrical and Computer Engineering, Jilin Jianzhu University, Changchun 130118 (China); Zhao, Ying [Institute of Photo Electronics thin Film Devices and Technology of Nankai University, Key Laboratory of Photoelectronic Thin Film Devices and Technology, Tianjin 300071 (China); Zhang, Xiaodan, E-mail: xdzhang@nankai.edu.cn [Institute of Photo Electronics thin Film Devices and Technology of Nankai University, Key Laboratory of Photoelectronic Thin Film Devices and Technology, Tianjin 300071 (China)

2017-08-15

Highlights: • A new structure of Mo back contact was proposed. • The rough surface of Mo films gained diffuse reflectivity. • The performance of CZTSe cells were improved. - Abstract: A mixed RF/DC sputtering multilayer molybdenum (Mo) was realized to benefit different properties of films deposited in each mode. The bottom layer was deposited by RF sputtering to increase total reflectance and adherence, and the top layer was deposited by DC sputtering to modify the morphology of molybdenum films and increase light scattering. The morphologies of co-evaporated Cu{sub 2}ZnSnSe{sub 4} (CZTSe) films had not been reliably observed influenced by the top layer of Mo films. Only noticeable change was the lower reflectance of CZTSe films deposited on rough back contact which can be attributed to the diffuse reflection of back contact. The conversion efficiency of completed device is improved by using the novel Mo back contact, especially for the short-circuit current density (Jsc) about 11.7% enhancement.

In situ Oxidation of Ultrathin Silver Films on Ni(111)

International Nuclear Information System (INIS)

Meyer, A.; Flege, I.; Senanayake, S.; Kaemena, B.; Rettew, R.; Alamgir, F.; Falta, J.

2011-01-01

Oxidation of silver films of one- and two-monolayer thicknesses on the Ni(111) surface was investigated by low-energy electron microscopy at temperatures of 500 and 600 K. Additionally, intensity-voltage curves were measured in situ during oxidation to reveal the local film structure on a nanometer scale. At both temperatures, we find that exposure to molecular oxygen leads to the destabilization of the Ag film with subsequent relocation of the silver atoms to small few-layer-thick silver patches and concurrent evolution of NiO(111) regions. Subsequent exposure of the oxidized surface to ethylene initiates the transformation of bilayer islands back into monolayer islands, demonstrating at least partial reversibility of the silver relocation process at 600 K.

Study of film graphene/graphene oxide obtained by partial reduction chemical of oxide graphite; Estudo de filme de grafeno/oxido de grafeno obtido por reducao quimica parcial do oxido de grafite

Energy Technology Data Exchange (ETDEWEB)

Gascho, J.L.S.; Costa, S.F.; Hoepfner, J.C.; Pezzin, S.H., E-mail: juliagascho@hotmail.com [Universidade do Estado de Santa Catarina (UDESC), Joinville, SC (Brazil). Programa de Pos-Graduacao em Ciencia e Engenharia de Materiais

2014-07-01

This study investigated the morphology of graphene/graphene oxide film obtained by partial chemical reduction of graphite oxide (OG) as well as its resistance to solvents. Films of graphene/graphene oxide are great candidates for replacement of indium oxide doped with tin (ITO) in photoelectric devices. The OG was obtained from natural graphite, by Hummer's method modified, and its reduction is made by using sodium borohydride. Infrared spectroscopy analysis of Fourier transform (FTIR), Xray diffraction (XRD) and scanning electron microscopy, high-resolution (SEM/FEG) for the characterization of graphene/graphene oxide film obtained were performed. This film proved to be resilient, not dispersing in any of the various tested solvents (such as ethanol, acetone and THF), even under tip sonication, this resistance being an important property for the applications. Furthermore, the film had a morphology similar to that obtained by other preparation methods.(author)

Synthesis of electro-active manganese oxide thin films by plasma enhanced chemical vapor deposition

Energy Technology Data Exchange (ETDEWEB)

Merritt, Anna R. [Energetics Research Division, Naval Air Warfare Center Weapons Division, China Lake, CA 93555 (United States); Rajagopalan, Ramakrishnan [Department of Engineering, The Pennsylvania State University, Dubois, PA 15801 (United States); Materials Research Institute, The Pennsylvania State University, University Park, PA 16802 (United States); Carter, Joshua D. [Energetics Research Division, Naval Air Warfare Center Weapons Division, China Lake, CA 93555 (United States)

2014-04-01

The good stability, cyclability and high specific capacitance of manganese oxide (MnO{sub x}) has recently promoted a growing interest in utilizing MnO{sub x} in asymmetric supercapacitor electrodes. Several literature reports have indicated that thin film geometries of MnO{sub x} provide specific capacitances that are much higher than bulk MnO{sub x} powders. Plasma enhanced chemical vapor deposition (PECVD) is a versatile technique for the production of metal oxide thin films with high purity and controllable thickness. In this work, MnO{sub x} thin films deposited by PECVD from a methylcyclopentadienyl manganese tricarbonyl precursor are presented and the effect of processing conditions on the quality of MnO{sub x} films is described. The film purity and oxidation state of the MnO{sub x} films were studied by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Preliminary electrochemical testing of MnO{sub x} films deposited on carbon fiber electrodes in aqueous electrolytes indicates that the PECVD synthesized films are electrochemically active. - Highlights: • Plasma enhanced chemical vapor deposition of manganese oxide thin films. • Higher plasma power and chamber pressure increase deposition rate. • Manganese oxide thin films are electrochemically active. • Best electrochemical performance observed for pure film with low stress • Lower capacitance observed at higher scan rates despite thin film geometry.

Influence of annealing on texture properties of cerium oxide thin films

International Nuclear Information System (INIS)

Arunkumar, P.; Suresh Babu, K.; Ramaseshan, R.; Dash, S.

2013-01-01

Future power demand needs an energy source with higher efficiency, better power density, clean energy and fuel flexibility. Solid oxide fuel cell (SOFC) is one of the potential sources for future needs. Though the polymer and direct methanol based electrolyte are much suitable, for versatile applications (portable devices) they are having major challenges such as design, platinum based catalyst, lower power density and fuel flexibility (free from hydrocarbons). However, in SOFC the high operating temperature is the only major issue. Operating temperature of SOFC could be reduced by proper selection of electrolyte material which should have minimum ionic conductivity of 0.1 Scm -1 at reduced activation energy. This can be achieved by thin film based doped cerium oxide electrolyte for SOFC, leads to Intermediate Temperature Solid Oxide Fuel Cell (ITSOFC). In the present work, we focus on the synthesis of cerium oxide and 20 mol % samarium doped cerium oxide (SDC) nanoparticles by co-precipitation method and to synthesis thin films of the same. Pellets of those powders were heat treated at different temperatures and used as targets for e-beam evaporation to fabricate thin film based electrolyte. Stoichiometry of both powders and thin films were confirmed by XRF and EPMA. GIXRD profiles of ceria and SDC thin films are shown below and a preferred orientation effect is observed in SDC films. In SDC films the X-ray peaks have a shift towards lower angles, due to the difference in ionic radii of Ce 4+ and Sm 3+ . The band gap of CeO 2 (2.88 eV) from optical absorption technique indicates the presence of Ce 3+ with Ce 4+ , indirectly shows the concentration of oxygen vacancies which is required for the thin film electrolyte

Study of thin metal films and oxide materials for nanoelectronics applications

OpenAIRE

De Los Santos Valladares, Luis

2012-01-01

Appendix A Pages 132-134 have been removed from this online version of the thesis for publisher copyright reasons. These had contained page images from the cover of Nanotechnology, Vol. 21, Nov 2010 and its corresponding web alert Different types of thin metal films and oxide materials are studied for their potential application in nanoelectronics: gold and copper films, nickel nanoelectrodes, oxide nanograin superconductors, carboxyl ferromagnetic microspheres and graphene oxide...

Lipase immobilized on nanostructured cerium oxide thin film coated on transparent conducting oxide electrode for butyrin sensing

Energy Technology Data Exchange (ETDEWEB)

Panky, Sreedevi; Thandavan, Kavitha [Centre for Nanotechnology and Advanced Biomaterials (CeNTAB), SASTRA University, Thanjavur 613 401, Tamil Nadu (India); School of Chemical and Biotechnology, SASTRA University, Thanjavur 613 401, Tamil Nadu (India); Sivalingam, Durgajanani [Centre for Nanotechnology and Advanced Biomaterials (CeNTAB), SASTRA University, Thanjavur 613 401, Tamil Nadu (India); School of Electrical and Electronics Engineering, SASTRA University, Thanjavur 613 401, Tamil Nadu (India); Sethuraman, Swaminathan; Krishnan, Uma Maheswari [Centre for Nanotechnology and Advanced Biomaterials (CeNTAB), SASTRA University, Thanjavur 613 401, Tamil Nadu (India); School of Chemical and Biotechnology, SASTRA University, Thanjavur 613 401, Tamil Nadu (India); Jeyaprakash, Beri Gopalakrishnan [Centre for Nanotechnology and Advanced Biomaterials (CeNTAB), SASTRA University, Thanjavur 613 401, Tamil Nadu (India); School of Electrical and Electronics Engineering, SASTRA University, Thanjavur 613 401, Tamil Nadu (India); Rayappan, John Bosco Balaguru, E-mail: rjbosco@ece.sastra.edu [Centre for Nanotechnology and Advanced Biomaterials (CeNTAB), SASTRA University, Thanjavur 613 401, Tamil Nadu (India); School of Electrical and Electronics Engineering, SASTRA University, Thanjavur 613 401, Tamil Nadu (India)

2013-01-15

Nanostructured cerium oxide (CeO{sub 2}) thin films were deposited on transparent conducting oxide (TCO) substrate using spray pyrolysis technique with cerium nitrate salt, Ce(NO{sub 3}){sub 3}{center_dot}6H{sub 2}O as precursor. Fluorine doped cadmium oxide (CdO:F) thin film prepared using spray pyrolysis technique acts as the TCO film and hence the bare electrode. The structural, morphological and elemental characterizations of the films were carried out using X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and energy dispersive X-ray analysis (EDX) respectively. The diffraction peak positions in XRD confirmed the formation of highly crystalline ceria with cubic structure and FE-SEM images showed uniform adherent films with granular morphology. The band gaps of CeO{sub 2} and TCO were found to be 3.2 eV and 2.6 eV respectively. Lipase enzyme was physisorbed on the surface of CeO{sub 2}/TCO film to form the lipase/nano-CeO{sub 2}/TCO bioelectrode. Sensing studies were carried out using cyclic voltammetry and amperometry, with lipase/nano-CeO{sub 2}/TCO as working electrode and tributyrin as substrate. The mediator-free biosensor with nanointerface exhibited excellent linearity (0.33-1.98 mM) with a lowest detection limit of 2 {mu}M with sharp response time of 5 s and a shelf life of about 6 weeks. -- Graphical abstract: Nanostructured cerium oxide thin films were deposited on transparent conducting oxide (TCO) substrate using spray pyrolysis technique. Fluorine doped cadmium oxide (CdO:F) thin film acts as the TCO film and hence the working electrode. Lipase enzyme was physisorbed on the surface of CeO{sub 2}/TCO film and hence the lipase/nano-CeO{sub 2}/TCO bioelectrode has been fabricated. Sensing studies were carried out using cyclic voltammetry and amperometry with tributyrin as substrate. The mediator-free biosensor with nanointerface exhibited excellent linearity (0.33-1.98 mM) with a lowest detection limit of 2 {mu}M with sharp

Wide-range measurement of thermal effusivity using molybdenum thin film with low thermal conductivity for thermal microscopes

Science.gov (United States)

Miyake, Shugo; Matsui, Genzou; Ohta, Hiromichi; Hatori, Kimihito; Taguchi, Kohei; Yamamoto, Suguru

2017-07-01

Thermal microscopes are a useful technology to investigate the spatial distribution of the thermal transport properties of various materials. However, for high thermal effusivity materials, the estimated values of thermophysical parameters based on the conventional 1D heat flow model are known to be higher than the values of materials in the literature. Here, we present a new procedure to solve the problem which calculates the theoretical temperature response with the 3D heat flow and measures reference materials which involve known values of thermal effusivity and heat capacity. In general, a complicated numerical iterative method and many thermophysical parameters are required for the calculation in the 3D heat flow model. Here, we devised a simple procedure by using a molybdenum (Mo) thin film with low thermal conductivity on the sample surface, enabling us to measure over a wide thermal effusivity range for various materials.

Ductility Enhancement of Molybdenum Phase by Nano-sized Oxide Dispersions

Energy Technology Data Exchange (ETDEWEB)

Kang, Bruce

2008-07-18

The objective of this research is to understand and to remedy the impurity effects for room-temperature ductility enhancement of molybdenum (Mo) based alloys by the inclusion of nano-sized metal oxide dispersions. This research combines theoretical, computational, and experimental efforts. The results will help to formulate systematic strategies in searching for better composed Mo-based alloys with optimal mechanical properties. For this project, majority of the research effort was directed to atomistic modeling to identify the mechanisms responsible for the oxygen embrittling and ductility enhancement based on fundamental electronic structure analysis. Through first principles molecular dynamics simulations, it was found that the embrittling impurity species were attracted to the metal oxide interface, consistent with previous experiments. Further investigation on the electronic structures reveals that the presence of embrittling species degrades the quality of the metallic chemical bonds in the hosting matrix in a number of ways, the latter providing the source of ductility. For example, the spatial flexibility of the bonds is reduced, and localization of the impurity states occurs to pin the dislocation flow. Rice’s criterion has been invoked to explain the connections of electronic structure and mechanical properties. It was also found that when impurity species become attracted to the metal oxide interface, some of the detrimental effects are alleviated, thus explaining the observed ductility enhancement effects. These understandings help to develop predictive capabilities to facilitate the design and optimization of Mo and other high temperature alloys (e.g. ODS alloys) for fossil energy materials applications. Based on the theoretical and computational studies, the experimental work includes the preparation of Mo powders mixed with candidate nano-sized metal oxides, which were then vacuum hot-pressed to make the Mo alloys. Several powder mixing methods

Annealing effects on the structural and optical properties of vanadium oxide film obtained by the hot-filament metal oxide deposition technique (HFMOD)

Energy Technology Data Exchange (ETDEWEB)

Scarminio, Jair; Silva, Paulo Rogerio Catarini da, E-mail: scarmini@uel.br, E-mail: prcsilva@uel.br [Universidade Estadual de Londrina (UEL), PR (Brazil). Departamento de Fisica; Gelamo, Rogerio Valentim, E-mail: rogelamo@gmail.com [Universidade Federal do Triangulo Mineiro (UFTM), Uberaba, MG (Brazil); Moraes, Mario Antonio Bica de, E-mail: bmoraes@mailhost.ifi.unicamp.br [Universidade Estadual de Campinas (UNICAMP), SP (Brazil)

2017-01-15

Vanadium oxide films amorphous, nonstoichiometric and highly absorbing in the optical region were deposited on ITO-coated glass and on silicon substrates, by the hot-filament metal oxide deposition technique (HFMOD) and oxidized by ex-situ annealing in a furnace at 200, 300, 400 and 500 deg C, under an atmosphere of argon and rarefied oxygen. X-ray diffraction, Raman and Rutherford backscattering spectroscopy as well as optical transmission were employed to characterize the amorphous and annealed films. When annealed at 200 and 300 deg C the as-deposited opaque films become transparent but still amorphous. Under treatments at 400 and 500 deg C a crystalline nonstoichiometric V{sub 2}O{sub 5} structure is formed. All the annealed films became semiconducting, with their optical absorption coefficients changing with the annealing temperature. An optical gap of 2.25 eV was measured for the films annealed at 400 and 500 deg C. The annealing in rarefied oxygen atmosphere proved to be a useful and simple ex-situ method to modulate the structural and optical properties of vanadium oxide films deposited by HFMOD technique. This technique could be applied to other amorphous and non-absorbing oxide films, replacing the conventional and sometimes expensive method of modulate desirable film properties by controlling the film deposition parameters. Even more, the HFMOD technique can be an inexpensive alternative to deposit metal oxide films. (author)

Electrosprayed Metal Oxide Semiconductor Films for Sensitive and Selective Detection of Hydrogen Sulfide

Directory of Open Access Journals (Sweden)

Maryam Siadat

2009-11-01

Full Text Available Semiconductor metal oxide films of copper-doped tin oxide (Cu-SnO2, tungsten oxide (WO3 and indium oxide (In2O3 were deposited on a platinum coated alumina substrate employing the electrostatic spray deposition technique (ESD. The morphology studied with scanning electron microscopy (SEM and atomic force microscopy (AFM shows porous homogeneous films comprising uniformly distributed aggregates of nano particles. The X-ray diffraction technique (XRD proves the formation of crystalline phases with no impurities. Besides, the Raman cartographies provided information about the structural homogeneity. Some of the films are highly sensitive to low concentrations of H2S (10 ppm at low operating temperatures (100 and 200 °C and the best response in terms of Rair/Rgas is given by Cu-SnO2 films (2500 followed by WO3 (1200 and In2O3 (75. Moreover, all the films exhibit no cross-sensitivity to other reducing (SO2 or oxidizing (NO2 gases.

Oxidant-Dependent Thermoelectric Properties of Undoped ZnO Films by Atomic Layer Deposition

KAUST Repository

Kim, Hyunho

2017-02-27

Extraordinary oxidant-dependent changes in the thermoelectric properties of undoped ZnO thin films deposited by atomic layer deposition (ALD) have been observed. Specifically, deionized water and ozone oxidants are used in the growth of ZnO by ALD using diethylzinc as a zinc precursor. No substitutional atoms have been added to the ZnO films. By using ozone as an oxidant instead of water, a thermoelectric power factor (σS) of 5.76 × 10 W m K is obtained at 705 K for undoped ZnO films. In contrast, the maximum power factor for the water-based ZnO film is only 2.89 × 10 W m K at 746 K. Materials analysis results indicate that the oxygen vacancy levels in the water- and ozone-grown ZnO films are essentially the same, but the difference comes from Zn-related defects present in the ZnO films. The data suggest that the strong oxidant effect on thermoelectric performance can be explained by a mechanism involving point defect-induced differences in carrier concentration between these two oxides and a self-compensation effect in water-based ZnO due to the competitive formations of both oxygen and zinc vacancies. This strong oxidant effect on the thermoelectric properties of undoped ZnO films provides a pathway to improve the thermoelectric performance of this important material.

Hybrid manganese oxide films for supercapacitor application prepared by sol-gel technique

International Nuclear Information System (INIS)

Chen, Chin-Yi; Wang, Sheng-Chang; Tien, Yue-Han; Tsai, Wen-Ta; Lin, Chung-Kwei

2009-01-01

Hybrid films were prepared by adding various concentrations of meso-carbon microbeads (MCMB) during sol-gel processing of manganese oxide films. The heat-treated films were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). In addition, electrochemical performance of the MCMB-added Mn-oxide hybrid coatings was evaluated by cyclic voltammetry (CV) and compared with its unadded counterpart. Experimental results showed that Mn-oxide films exhibited a mixture of Mn 2 O 3 and Mn 3 O 4 phases. The higher the heat-treatment temperature, the more Mn 2 O 3 can be observed. The specific capacitance of the unadded Mn-oxide electrodes is 209 F/g. Because the MCMB particles provide more interfacial surface area for electrochemical reactions, a significant improvement can be noticed by adding MCMB in Mn-oxide coatings. The 300 o C heat-treated hybrid Mn-oxide coating with a Mn/MCMB ratio of 10/1 exhibits the highest value of 350 F/g, showing a ∼ 170% increase in specific capacitance.

Compositional analysis of silicon oxide/silicon nitride thin films

Directory of Open Access Journals (Sweden)

Meziani Samir

2016-06-01

Full Text Available Hydrogen, amorphous silicon nitride (SiNx:H abbreviated SiNx films were grown on multicrystalline silicon (mc-Si substrate by plasma enhanced chemical vapour deposition (PECVD in parallel configuration using NH3/SiH4 gas mixtures. The mc-Si wafers were taken from the same column of Si cast ingot. After the deposition process, the layers were oxidized (thermal oxidation in dry oxygen ambient environment at 950 °C to get oxide/nitride (ON structure. Secondary ion mass spectroscopy (SIMS, Rutherford backscattering spectroscopy (RBS, Auger electron spectroscopy (AES and energy dispersive X-ray analysis (EDX were employed for analyzing quantitatively the chemical composition and stoichiometry in the oxide-nitride stacked films. The effect of annealing temperature on the chemical composition of ON structure has been investigated. Some species, O, N, Si were redistributed in this structure during the thermal oxidation of SiNx. Indeed, oxygen diffused to the nitride layer into Si2O2N during dry oxidation.

Properties of Co-deposited indium tin oxide and zinc oxide films using a bipolar pulse power supply and a dual magnetron sputter source

International Nuclear Information System (INIS)

Hwang, Man-Soo; Seob Jeong, Heui; Kim, Won Mok; Seo, Yong Woon

2003-01-01

Multilayer coatings consisting of metal layers sandwiched between transparent conducting oxide layers are widely used for flat panel display electrodes and electromagnetic shield coatings for plasma displays, due to their high electrical conductivity and light transmittance. The electrical and optical properties of these multilayer films depend largely on the surface characteristics of the transparent conducting oxide thin films. A smoother surface on the transparent conducting oxide thin films makes it easier for the metal layer to form a continuous film, thus resulting in a higher conductivity and visible light transmittance. Indium tin oxide (ITO) and zinc oxide (ZnO) films were co-deposited using a dual magnetron sputter and a bipolar pulse power supply to decrease the surface roughness of the transparent conducting oxide films. The symmetric pulse mode of the power supply was used to simultaneously sputter an In 2 O 3 (90 wt %) : SnO 2 (10 wt %) target and a ZnO target. We varied the duty of the pulses to control the ratio of ITO : ZnO in the thin films. The electrical and optical properties of the films were studied, and special attention was paid to the surface roughness and the crystallinity of the films. By co-depositing ITO and ZnO at a pulse duty ratio of ITO:ZnO=45:45 using a dual magnetron sputter and a bipolar pulse power supply, we were able to obtain amorphous transparent conducting oxide films with a very smooth surface which had a Zn-rich buffer layer under a In-rich surface layer. All of the films exhibited typical electrical and optical properties of transparent conducting oxide films deposited at room temperature

Structural and photoluminescent properties of a composite tantalum oxide and silicon nanocrystals embedded in a silicon oxide film

International Nuclear Information System (INIS)

Díaz-Becerril, T.; Herrera, V.; Morales, C.; García-Salgado, G.; Rosendo, E.; Coyopol, A.; Galeazzi, R.; Romano, R.; Nieto-Caballero, F.G.; Sarmiento, J.

2017-01-01

Tantalum oxide crystals encrusted in a silicon oxide matrix were synthesized by using a hot filament chemical vapor deposition system (HFCVD). A solid source composed by a mixture in different percentages of Ta 2 O 5 and silicon (Si) powders were used as reactants. The films were grown at 800 °C and 1000 °C under hydrogen ambient. The deposited films were characterized by X-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HRTEM) and photoluminescence (PL) at room temperature. From the XPS results it was confirmed the formation of a mixture of Tantalum oxide, silicon oxide and Si nanoparticles (Ta 2 O 5- SiO 2 -Si(nc)) as seen from the Si (2p) and Ta (4f) lines corresponding to Si + and Ta + states respectively. Ta 2 O 5 and Si nanocrystals (Si-NCs) embedded in the silicon oxide films were observed on HRTEM images which corroborate the XPS results. Finally the emission properties of the films exhibited a broad band from 400 to 850 nm caused by the independent PL properties of tantalum oxide and Si-NCs that compose the film. The intensity of the emissions was observed to be dependent on both temperature of deposition and the ratio Ta 2 O 5 /Si, used as initial reactants. Results from this work might supply useful data for the development of future light emitter devices.

Oxide films on magnesium and magnesium alloys

International Nuclear Information System (INIS)

Shih, T.-S.; Liu, J.-B.; Wei, P.-S.

2007-01-01

Magnesium alloys are very active and readily ignite during heating and melting. In this study, we discuss the combustion of magnesium and magnesium alloys and propose prospective anti-ignition mechanisms for magnesium alloys during the heating process. When magnesium and magnesium alloys were heated in air, the sample surfaces produced layers of thermally formed oxides. These thermally formed oxides played an important role in affecting the combustion of the magnesium and magnesium alloys. When magnesium was heated in air, brucite that formed in the early stage was then transformed into periclase by dehydroxylation. By extending the heating time, more periclase formed and increased in thickness which was associated with microcracks formation. When magnesium was heated in a protective atmosphere (SF 6 ), a film of MgF 2 formed at the interface between the oxide layer and the Mg substrate. This film generated an anti-ignition behavior which protected the substrate from oxidation. When solution-treated AZ80 alloy was heated, spinel developed at the interface between the thermally formed oxide layer and the Mg substrate, improving the anti-ignition properties of the substrate. In addition, we also explain the effects of beryllium in an AZB91 alloy on the ignition-proofing behavior

Local electrical properties of thermally grown oxide films formed on duplex stainless steel surfaces

Science.gov (United States)

Guo, L. Q.; Yang, B. J.; He, J. Y.; Qiao, L. J.

2018-06-01

The local electrical properties of thermally grown oxide films formed on ferrite and austenite surfaces of duplex stainless steel at different temperatures were investigated by Current sensing atomic force microscopy, X-ray Photoelectron Spectroscopy (XPS) and Auger Electron Spectroscopy (AES). The current maps and XPS/AES analyses show that the oxide films covering austenite and ferrite surfaces formed at different temperatures exhibit different local electrical characteristics, thickness and composition. The dependence of electrical conductivity of oxide films covering austenite and ferrite surface on the formation temperature is attributed to the film thickness and semiconducting structures, which is intrinsically related to thermodynamics and kinetics process of film grown at different temperature. This is well elucidated by corresponding semiconductor band structures of oxide films formed on austenite and ferrite phases at different temperature.

Picosecond laser registration of interference pattern by oxidation of thin Cr films

Energy Technology Data Exchange (ETDEWEB)

Veiko, Vadim; Yarchuk, Michail [ITMO University, Kronverksky Ave. 49, St. Petersburg, 197101 (Russian Federation); Zakoldaev, Roman, E-mail: zakoldaev@gmail.com [ITMO University, Kronverksky Ave. 49, St. Petersburg, 197101 (Russian Federation); Gedvilas, Mindaugas; Račiukaitis, Gediminas [Center for Physical Sciences and Technology, Savanoriu Ave. 231, LT-02300, Vilnius (Lithuania); Kuzivanov, Michail; Baranov, Alexander [ITMO University, Kronverksky Ave. 49, St. Petersburg, 197101 (Russian Federation)

2017-05-15

Highlights: • Periodical patterning of thin films was achieved by combining two technologies. • Selective chemical etching was combined with laser-induced oxidation. • Formation of the protective oxide layer prevented of chromium film from etching. • 1D binary grating with the chromium stripe width of 750 nm was fabricated. - Abstract: The laser oxidation of thin metallic films followed by its selective chemical etching is a promising method for the formation of binary metal structures on the glass substrates. It is important to confirm that even a single ultrashort laser pulse irradiation is able to create the protective oxide layer that makes possible to imprint the thermochemical image. Results of the thermo-chemical treatment of thin chromium films irradiated by picosecond laser pulse utilizing two and four beam interference combined with the chemical etching are presented. The spatial resolution of this method can be high enough due to thermo-chemical sharpening and can be close to the diffraction limit. Micro-Raman spectroscopy was applied for characterization of the chemical composition of the protective oxide layers formed under atmospheric conditions on the surface of thin chromium films.

Electrophoretic deposition of PTFE particles on porous anodic aluminum oxide film and its tribological properties