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116 results on '"Falcony, C."'

26. The current test results for two models of HTS cables on CASAT Project

Author

Sytnikov, V.E., Dolgosheev, P.I., Soloviev, M.G., Belij, D.I., Nieto, L., Perez, A., Gonzalez, A., Maya, M., Ortiz, F., Falcony, C., Jergel, M., and Morales, A.

Subjects
Superconductors -- Research, Electrical cables -- Research, Business, Electronics, Electronics and electrical industries
Abstract

Testing of two models of high temperature superconducting (HTS) cables is decribed and discussed.

Published
2003

32. Tl-based films grown on silver tape substrates

Author

Falcony, C., Jergel, M., Morales, A., Garcia, M., Hernandez, R.T., De Ita, A., Cabanas-Moreno, J.G., Palacios G., J., and Martinez, R.

Subjects
High temperature superconductivity -- Research, High temperature superconductors -- Research, Thin films -- Research, Business, Electronics, Electronics and electrical industries
Abstract

A two-step procedure for producing Tl-based films on silver tape substrates has been developed. The Ba-Ca-Cu precursors were first deposited on a silver tape from an aerosol and then thallinated in a closed crucible with a source of Tl-oxide pellet. Scanning electron microscopy results indicate the formation of plate-like grains and strong c-axis orientation. The best films had a Tc values higher than 100 K. Pole figure measurements show good (001) bi-axial texturing.

Published
1999

35. Luminescent polystyrene films, a novel way to reduce styrofoam residues

Author

S. Carmona-Téllez, Alarcón-Flores, G., Zaleta-Alejandre, E., Rivera-Alvarez, Z., Meza-Rocha, A. N., Martínez-Martínez, R., Murrieta, H. S., Aguilar-Frutis, M., and Falcony, C.

Subjects
white light emission, Física, Astronomía y Matemáticas, polymeric films, Spray pyrolysis, polystyrene
Abstract

"Polystyrene (PS) films doped with blue, yellow and red organic pigments have been deposited on glass and on commercial LED chips by spray pyrolysis using recycled PS as precursor, at deposition rates between 100 and 200 A° /s. Doped films have roughness between 100 and 2500 °A depending on the kind of pigment used; the surface morphology shows that the organic pigments incorporate into the polystyrene host forming globular particles of about 2 ¹m in diameter. The organic pigments used have luminescent emissions peaked at 440, 509 and 590 nm. The introduction of the proper combination of pigments on the PS film deposited on the LED chips renders a white light emission with (0.29, 0.37) and (0.30, 0.33) CIE (Commission international de l’ ´eclairage) color coordinates. It was determined that the exposure to violet light degrades the luminescent characteristics, however, blue light is not energetic enough to cause a degradation of the luminescent layer over similar period of time."

Published
2015

37. White and yellow light emission from ZrO2:Dy3+ nanocrystals synthesized by a facile chemical technique.

Author

Báez-Rodríguez, A., Albarrán-Arreguín, D., García-Velasco, A. C., Álvarez-Fregoso, O., García-Hipólito, M., Álvarez-Pérez, M. A., Zamora-Peredo, L., and Falcony, C.

Subjects
NANOCRYSTALS, ZIRCONIUM oxide, CRYSTAL structure, X-ray diffraction, ANNEALING of crystals, ATOMIC force microscopy, LUMINESCENCE
Abstract

White and yellow light were obtained from ZrO2:Dy3+ nanocrystals which were synthesized by the solvent evaporation technique. The crystalline structure was studied by X-ray diffraction, resulting in a tetragonal and monoclinic mixture phases of ZrO2 when the powders were annealed at 600 °C and the zirconia monoclinic phase when they were thermal treated at 1000 °C. By means of atomic force microscopy images was observed that the synthesized powders are constituted by nanocrystals about 20 nm for the samples annealed at 600 °C, whereas samples annealed at 1000 °C were constituted by crystals about 135 nm, these features were confirmed by TEM images. Luminescence properties were analyzed by means of photo and cathodoluminescence; exhibiting emissions in the white light region of the chromatic diagram. In the case of photoluminescence white-warm color (x = 0.35, y = 0.37) was observed, which is close to pure white color; while for cathodoluminescence the emission was yellowish with coordinates (x = 0.39, y = 0.39) in the chromatic diagram. PL decay time measurements were carried out; a lifetime of 0.66 ms was found. In addition, the PL quantum efficiency was measured; the obtained value was as high as 45%. [ABSTRACT FROM AUTHOR]

Published
2018
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39. Characterization of Superconducting Magnesium-Diboride Films on Glassy Carbon and Sapphire Substrates

Author

Andrade, E., Rochah, M. F., Zavala, E. P., Matej Jergel, and Falcony, C.

Subjects
Superconducting MgB2 films, RBS/NRA analyses, Física, Astronomía y Matemáticas, IBA methods, NRA analyses, RBS
Abstract

"IBA methods were applied to measure elemental depth profiles of precursors and superconducting MgB2 thin films deposited on glassy carbon (Good Fellows) and sapphire (Al2O3) substrates. For each type of substrates we obtained a pair of samples i.e. one amorphous precursor and one superconducting film which were then characterized. A 3He+ beam was used to bombard both, precursors and superconducting films in order to obtain the samples elemental composition profiles. The zero resistance Tcoand the middle of transition Tcm values were 26.0K and 29.7K for the MgB2 film deposited on glassy carbon substrate. In the case of sapphire substrate the Tco and Tcm values were 25.0K and 27.9K, respectively."

Published
2008

46. Remote plasma chemical vapor deposition silicon oxynitride thin films: Dielectric properties

Author

Hernández-Vélez, M., Sánchez, Olga, Fernández-Gutiérrez, F., Falcony, C., Martínez Duart, J. M., Hernández-Vélez, M., Sánchez, Olga, Fernández-Gutiérrez, F., Falcony, C., and Martínez Duart, J. M.

Abstract

Silicon oxynitride thin films have been deposited using remote plasma chemical vapor deposition from SiCl4 + NH3 + O2 gas mixtures. The stoichiometry of the deposited films varies from that corresponding to the silicon oxide to a stoichiometry very close to silicon nitride when the NH3/O2 gas ratio is changed in the plasma. The approximate compositions of the films were determined by Rutherford backscattering spectroscopy and nuclear reaction analysis, and the local bonding arrangements were determined by infrared spectroscopy. Analysis of metal–insulator–semiconductor devices under the effect of and external sinusoidal electric field (dielectric spectrometry) indicates the presence of traps centers in the Si–SiO2 interface. Correlations between the local bonded structures in the oxynitride and the conduction and polarization processes detected in the films are also discussed.

Published
1998

48. Optical and structural characteristics of Y2O3 thin films synthesized from yttrium acetylacetonate.

Author

Alarcón-Flores, G., Aguilar-Frutis, M., García-Hipolito, M., Guzmán-Mendoza, J., Canseco, M., and Falcony, C.

Subjects
SURFACES (Technology), SPECTRUM analysis, THICK films, ATOMIZATION, INFRARED spectroscopy, SCANNING probe microscopy, SURFACE roughness, MASS (Physics), THERMOGRAVIMETRY
Abstract

Yttrium oxide thin films are deposited on silicon substrates using the ultrasonic spray pyrolysis technique from the thermal decomposition of a β-diketonate, yttrium acetylacetonate (Y(acac)3). The decomposition of Y(acac)3 was studied by thermogravimetry, differential scanning calorimetry, mass spectrometry, and infrared spectroscopy. It was found that a β-diketone ligand is lost during the initial steps of decomposition of the Y(acac)3. The rest of the complex is then dissociated or degraded partially until Y2O3 is obtained in the final step with the presence of carbon related residues. Then the Y(acac)3 was used to synthesize Y2O3 thin films using the spray pyrolysis technique. The films were deposited on silicon substrates at temperatures in the range of 400–550 °C. The films were characterized by ellipsometry, infrared spectroscopy, atomic force microscopy, and X-ray diffraction. The films presented a low surface roughness with an index of refraction close to 1.8. The crystalline structure of the films depended on the substrate temperature; films deposited at 400 °C were mainly amorphous, but higher deposition temperatures (450–550 °C), resulted in polycrystalline with a cubic crystalline phase. [ABSTRACT FROM AUTHOR]

Published
2008
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49. Microstructural characteristics and carbon content of Al2O3films as a function of deposition parameters

Author

Guzmán-Mendoza, J., Garcia-Hipolito, M., Aguilar-Frutis, M., and Falcony, C.

Abstract

Microstructural characteristics and carbon content in aluminum oxide thin films deposited on silicon substrates are reported as a function of deposition parameters such as substrate temperature and molar concentration of the spraying solution. The films were deposited using the spray pyrolysis technique from a spraying solution of aluminum acetylacetonate (Al(acac)3), dissolved in N,N-dimethylformamide (N,N-DMF), at temperatures in the range from 500 to 650 °C. Water mist was added during the deposition process and no further post deposition thermal treatments were given to these films. The films have a stoichiometry close to that expected for Al2O3, although, residual carbon from the deposition process was found to be present in these films. The surface roughness of the films was less than 20 Å, with deposition rates up to 540 Å/min, low chemical etch rates and activation energies around 27.6 kJ/mol were also determined. High resolution transmission electron microscopy observation of these films show the presence of a tiny 5Al2O3: H2O crystalline phase embedded in a dense amorphous matrix. It was found that the average crystallite diameter of this phase depended on the deposition temperature as well as on the molar concentration of the spraying solution.

Published
2004
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50. Plasma enhanced chemical vapor deposition of SiO2films at low temperatures using SiCl4and O2

Author

Ortiz, A., Lopez, S., Falcony, C., Farias, M., Cota-Araiza, L., and Soto, G.

Abstract

Silicon dioxide films have been deposited by Plasma-Enhanced Chemical Vapor Deposition (PECVD) technique using SiCl4and O2as reactive materials. Infra-red transmittance, Auger electron spectroscopy analysis, ellipsometry, electrical, and chemical etch measurements have been used to characterize these films. It is possible to obtain good quality oxides at a substrate temperature of 200° C using a low flow of reactant gases. High flow of reactant gases results in highly non-homogeneous porous films. The best oxide films obtained show destructive breakdown at electrical fields above 4 MV/cm and a fixed charge density of the order of 2.6 × 1011charges/cm2.

Published
1990
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