Ursulo Galván, Mexico


Ursulo Galván, Mexico
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Martinez-Juarez J.,CIDS ICUAP | Diaz-Reyes J.,CIBA IPN | Juarez-Diaz G.,CINVESTAV | Galeazzi R.,CIDS ICUAP | Galvan-Arellano M.,CINVESTAV
Materials Science Forum | Year: 2010

Zinc oxide (ZnO) is a direct, wide band gap semiconductor material having many promising properties for UV/blue optoelectronics, transparent electronics, spintr spintronic devices and onic sensor applications. The ZnO is synthesized by the technique of Chemical Bath Deposition by microwaves heating (MW-CBD). The urea concentration in the solution is varied, maintaining constant t the zinc nitrate in ratio 1:1 ... 1:10. The physi physical properties of ZnO thin films were examined by X-ray diffraction (XRD), SEM SEM-EDS, and Raman scattering, which are convenient tools that can provide us with plenty of information about crystal structure and elementary excitons. By X X-rays one obtains that it has hexagonal polycrystalline wurtzite type structure. The IR absorption line at 3577 cm cm-1 detected at 300 K in bath chemical ZnO is assigned an O-H bond primarily aligned with the c c-axis of the crystal and bonding between Zn Zn-O (473cm 473cm-1, 532 cm , cm-1). The Raman spectra show the first order experimental Raman spectra of ZnO excited by 514.5 nm laser line. The first order Raman modes A1T, E1T, E 2(H), A1Land E1L are identified as the peaks sited at 385, 426, 437, 572 and 584 cm-1. © (2010) Trans Tech Publications.

Diaz-Reyes J.,CIBA IPN | Flores-Mena J.E.,FCE BUAP | Gutierrez-Arias J.M.,FCE BUAP | Morin-Castillo M.M.,FCE BUAP | And 4 more authors.
Advances in Sensors, Signals and Materials - 3rd WSEAS International Conference on Sensors and Signals, SENSIG'10, 3rd WSEAS International Conference on Materials Science, MATERIALS'10 | Year: 2010

This work presents a study of effect of annealing temperature on optical and structural properties of WO3 that has been deposited by hot-filament metal oxide deposition (HFMOD). X-ray diffraction shows that the as-deposited WO3 films present mainly monoclinic crystalline phase. The Raman spectrum shows four intense peaks that are typical Raman peaks of crystalline WO3 (m-phase) that corresponds to the stretching vibrations of the bridging oxygen that enhance and increase their intensity with the annealing temperature. gap can be varied from 2.92 to 3.15 eV by annealing WO3 from O to 500°C. The photoluminescence response of the asdeposited film presents two radiative transitions centered at 2.04 and 2.65 eV that are associated to oxygen vacancies.

Diaz-Reyes J.,CIBA IPN | Martinez-Juarez J.,CIDS ICUAP | Galeazzi R.,CIDS ICUAP | Juarez-Diaz G.,CIDS ICUAP | And 3 more authors.
Advances in Sensors, Signals and Materials - 3rd WSEAS International Conference on Sensors and Signals, SENSIG'10, 3rd WSEAS International Conference on Materials Science, MATERIALS'10 | Year: 2010

ZnO has received increasing attention and been recognized as a promising candidate for applications due to its optoelectronic properties in the UV range. The ZnO is grown by the technique of Chemical Bath Deposition activated by microwaves (CBD-μW). X-rays scattering yields a hexagonal polycrystalline wurtzite type structure. The Raman spectra present four main peaks at 444, 338, 104 and 78 cm-1 associated to the modes E2 high, (E2 high - E2 low), E 2 low and an unidentified band. The 300 K photoluminescence presents visible/UV radiative bands associated to vacancies of zinc and oxygen. In addition, it was carried out energy dispersive spectroscopy (EDS) measurements on the films to determine their stoichiometry, relating the intensity of radiative bands associated to oxygen and zinc vacancies.

Diaz-Reyes J.,CIBA IPN | Martinez-Juarez J.,CIDS ICUAP | Garcia M.L.,CIDS ICUAP | Juarez G.,CINVESTAV | Galeazzi R.,CIDS ICUAP
IOP Conference Series: Materials Science and Engineering | Year: 2014

A study of the growth and the physical properties of ZnO films deposited by chemical bath technique and annealed by microwave are presented. For the deposition solution the molar ratio between zinc nitrate and urea is varied in a range of 1:1... 1:10. By X-ray obtains that layers have hexagonal polycrystalline wurtzite type unitary cell. The Raman spectra show the first order experimental Raman spectra of ZnO. The first order Raman modes are identified in the ZnO Raman spectra. The 300K photoluminescence shows radiative bands labelled by red, yellow, green and violet bands, which are associated to defects of oxygen and zinc vacancies. By EDS measurements determined their stoichiometry, which allows relating it with the intensity of radiative bands associated to oxygen and zinc vacancies. © 2010 IOP Publishing Ltd.

Carrillo-Lopez J.,CIDS ICUAP | Luna-Lopez J.A.,CIDS ICUAP | Vivaldo-De La Cruz I.,CIDS ICUAP | Aceves-Mijares M.,National Institute of Astrophysics, Optics and Electronics | And 2 more authors.
Solar Energy Materials and Solar Cells | Year: 2012

A study of comparison of the electrical and optical characteristics of silicon solar cells (SC) with a layer of silicon oxide (SiO 2) deposited by SILOX, and silicon solar cells covered with a silicon rich oxide (SRO) film obtained by LPCVD containing silicon nanoparticles (Si-nps) was made. To increase the density of nanoparticles and thus improve the red photoluminescence, the SRO films were annealed at 1100 °C. Photoluminescence spectra and atomic force microscopy measurements of the silicon rich oxide films are presented and discussed, as well as currentvoltage curves and spectral response of the fabricated solar cells. Measurement of the open circuit voltage and short circuit current of the SC under UV light illumination was realized. The results demonstrate that the red luminescence of these films with silicon nanoparticles, produces large enhancement of current and voltage, with improved performance in the UV range. © 2012 Elsevier B.V. All rights reserved.

Luna-Lopez J.A.,CIDS ICUAP | Garcia-Salgado G.,CIDS ICUAP | Diaz-Becerril T.,CIDS ICUAP | Lopez J.C.,CIDS ICUAP | And 4 more authors.
Materials Science and Engineering B: Solid-State Materials for Advanced Technology | Year: 2010

In order to have optoelectronic functions integrated in a single chip, it is very important to obtain a silicon compatible material with an optimal photoluminescence response. The non-stoichiometric silicon oxide (SiO x) has shown photoluminescence response and is also compatible with silicon technology. In this work, the composition and optical properties of the SiOx films are studied using null ellipsometry, Fourier transformed infrared spectroscopy (FTIR), atomic force microscopy (AFM), and photoluminescence (PL). The SiOx films were growth to different temperatures. The IR absorption spectrum shows the presence of three typical Si-O-Si vibrations modes in SiO2. However, changes in their intensity and position were observed. Also, when growth temperature decreased, the Si-H vibrations modes were observed. These changes are directly related with compositional variation in the SiOx films due to the growth temperature. A PL spectrum shows a considerable emission in the range 400-850 nm that varies with the growth temperatures. © 2010 Elsevier B.V. All rights reserved.

Luna Lopez J.A.,CIDS ICUAP | Sosa Sanchez J.L.,CIDS ICUAP | Granillo Martinez S.,CIDS ICUAP | Carrillo Lopez J.,CIDS ICUAP | And 5 more authors.
Superficies y Vacio | Year: 2014

In this study a sandwich-type octa-substituted Erbium (III) bis-phthalocyanine compound of increased solubility was synthetized from a metal free phthalocyanine with the same substitution pattern using strictly dry reaction conditions. Then the pure product obtained from a chromatographic purification method was deposited as thin films by spin coating onto glass substrates to investigate its structural and optical properties. The UV-Vis spectrum shows the intense characteristic peaks of this kind of phthalocyanine compounds, particularly in the range from 560 to 630 nm. The chemical nature of the thin film material was corroborated through x-ray diffraction analysis and IR spectroscopy. Photoluminescence emission was observed for the films in the visible range. ©Sociedad Mexicana de Ciencia y Tecnología de Superficies y Materiales.

Garcia-Cruz M.L.,CIDS ICUAP | Martinez-Juarez J.,CIDS ICUAP | Martinez-Juarez J.,Research Center y Estudios Avanzados | Lopez-Salazar P.,CIDS ICUAP | And 3 more authors.
Physica Status Solidi (C) Current Topics in Solid State Physics | Year: 2010

Doped GaSb (Gallium Antimonide) films on p-GaSb substrates have been obtained by means of a low-cost and fastgrowth method: the liquid phase epitaxy (LPE) technique. The growth temperature was 400 °C, and the growth time was varied between1 and 5 min. Characterization of the films was performed by means of high resolution X-ray Diffraction, low temperature-photoluminiscence and current-voltage curve measurements. The X-ray diffraction pattern confirms a zincblende-type crystal structure with a high-thin peak centred at 30.36°. The PL spectra at 27 K allowed to confirm the band-gap energy to be 0.8 eV and the I-V curves presented a PN junction behavior which corresponds to the obtained structured. Metal contacts of Au-Zn and Au-Ge were placed to perform electrical characterization. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA.

Coyopol A.,CIDS ICUAP | Diaz T.,CIDS ICUAP | Garcia G.,CIDS ICUAP | Lopez R.,CIDS ICUAP | And 4 more authors.
IOP Conference Series: Materials Science and Engineering | Year: 2013

SiOx films were deposited in the temperature range of 800-1000 °C by hot wire chemical vapor deposition (HWCVD) technique. Annealing treatment for as-deposited samples was performed in nitrogen (N2) atmosphere at 1100 °C. The effect of annealing atmosphere on the structural properties of the deposited films was investigated by means of micro Raman, X-ray diffraction (XRD), Photoluminescence (PL) and high resolution electron microscopy (HRTEM) measurements. Micro-Raman studies revealed an increase in the crystalline volume fraction (Xc) in the deposited films after annealing. XRD patterns of the annealed films showed the formation of silicon crystals. HRTEM images confirmed the presence of silicon nanocrystals (Si-ncs) in both as-deposited and annealed films. Furthermore, the annealing treatment on the as-deposited samples at 900 and 1000 °C resulted in the observation a large number of Si-ncs with sizes between 3-15 nm. PL measurement shows a broad emission from 400 to 1100 nm. This emission was related with both Si-ncs and interfacial defects present in SiOx films. © Published under licence by IOP Publishing Ltd.

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