Sol-gel fabrication of active SiO2-ZnO glass-ceramic planar waveguides on silica-on-silicon substrates

AbstractNanocrystalline Ni0.5Zn0.5Fe2O4 thin films have been synthesized with various grain sizes by sol–gel method on polycrystalline silicon substrates. The morphology and microwave absorption properties of the films calcined in the 673–1073 K range were studied by using XRD, AFM, near–field evanescent microwave microscopy, coplanar waveguide and direct microwave heating measurements. All films were uniform without microcracks. The increase of the calcination temperature from 873 to 1073 K and time from 1 to 3h resulted in an increase of the grain size from 12 to 27 nm. The complex permittivity of the Ni-Zn ferrite films was measured in the frequency range of 2–15 GHz. The heating behavior was studied in a multimode microwave cavity at 2.4 GHz. The highest microwave heating rate in the temperature range of 315–355 K was observed in the film close to the critical grain size of 21 nm in diameter marked by the transition from single– to multi–domain structure of nanocrystals in Ni0.5Zn0.5Fe2O4 film and by a maximum in its coercivity.

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Effect of Precursor Sol Ageing on Sol-Gel Derived Ruthenium Oxide Thin Films

MRS Proceedings ◽

10.1557/proc-606-211 ◽

1999 ◽

Vol 606 ◽

Cited By ~ 4

Author(s):

S. Bhaskar ◽

S. B. Majumder ◽

P. S. Dobal ◽

R. S. Katiyar ◽

A. L. M. Cruz ◽

...

Keyword(s):

Thin Films ◽

Room Temperature ◽

Annealing Temperature ◽

Sol Gel ◽

Ruthenium Oxide ◽

Precursor Solution ◽

Silicon Substrates ◽

Solution Deposition ◽

Precursor Material ◽

Afm Analysis

AbstractIn the present work we have optimized the process parameters to yield homogeneous, smooth ruthenium oxide (RuO2) thin films on silicon substrates by a solution deposition technique using RuCl3.×.H2O as the precursor material. Films were annealed in a temperature range of 300°C to 700°C, and it was found that RuO2 crystallizes at a temperature as low as 400°C. The crystallinity of the films improves with increased annealing temperature and the resistivity decreases from 4.86µΩ-m (films annealed at 400°C) to 2.94pµΩ (films annealed at 700°C). Ageing of the precursor solution has a pronounced effect on the measured resistivities of RuO2 thin films. It was found that the measured room temperature resistivities increases from 2.94µΩ-m to 45.7µΩ-m when the precursor sol is aged for aged 60 days. AFM analysis on the aged films shows that the grain size and the surface roughness of the annealed films increase with the ageing of the precursor solution. From XPS analysis we have detected the presence of non-transformed RuCl3 in case of films prepared from aged solution. We propose, that solution ageing inhibits the transformation of RuCl3 to RuO2 during the annealing of the films. The deterioration of the conductivity with solution ageing is thought to be related with the chloride contamination in the annealed films.

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Novel Glass-Ceramics for Dental Application by Sol Gel Technique

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.396-398.153 ◽

2008 ◽

Vol 396-398 ◽

pp. 153-156 ◽

Cited By ~ 1

Author(s):

Xanthippi Chatzistavrou ◽

E. Hatzistavrou ◽

Nikolaos Kantiranis ◽

Lambrini Papadopoulou ◽

Eleana Kontonasaki ◽

...

Keyword(s):

Glass Ceramic ◽

Preparation Method ◽

Sol Gel ◽

Glass Ceramics ◽

Dental Restorations ◽

Gel Technique ◽

Gel Preparation ◽

Dental Applications ◽

Potential Use

The aim of this study was the fabrication using a sol-gel technique of a new glass-ceramic with potential use in dental applications. The characterization of the composition and microstructural properties of the produced material confirmed the similarity between the new sol-gel derived glass-ceramic and a commercial leucite based fluorapatite dental glass-ceramic. The produced material has potential application in dental restorations and it is expected to exhibit better control of composition, microstructure and properties due to the intrinsic advantages of the sol-gel preparation method.

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Placenta Derived Mesenchymal Stem Cells Hosted on RKKP Glass-Ceramic: A Tissue Engineering Strategy for Bone Regenerative Medicine Applications

BioMed Research International ◽

10.1155/2016/3657906 ◽

2016 ◽

Vol 2016 ◽

pp. 1-11 ◽

Cited By ~ 5

Author(s):

Mario Ledda ◽

Marco Fosca ◽

Angela De Bonis ◽

Mariangela Curcio ◽

Roberto Teghil ◽

...

Keyword(s):

Tissue Engineering ◽

Stem Cells ◽

Regenerative Medicine ◽

Glass Ceramic ◽

Phase Distribution ◽

Sol Gel ◽

Pcr Analysis ◽

Cycle Phase ◽

Cell Delivery ◽

Limiting Factor

In tissue engineering protocols, the survival of transplanted stem cells is a limiting factor that could be overcome using a cell delivery matrix able to support cell proliferation and differentiation. With this aim, we studied the cell-friendly and biocompatible behavior of RKKP glass-ceramic coated Titanium (Ti) surface seeded with human amniotic mesenchymal stromal cells (hAMSCs) from placenta. The sol-gel synthesis procedure was used to prepare the RKKP glass-ceramic material, which was then deposited onto the Ti surface by Pulsed Laser Deposition method. The cell metabolic activity and proliferation rate, the cytoskeletal actin organization, and the cell cycle phase distribution in hAMSCs seeded on the RKKP coated Ti surface revealed no significant differences when compared to the cells grown on the treated plastic Petri dish. The health of of hAMSCs was also analysed studying the mRNA expressions of MSC key genes and the osteogenic commitment capability using qRT-PCR analysis which resulted in being unchanged in both substrates. In this study, the combination of the hAMSCs’ properties together with the bioactive characteristics of RKKP glass-ceramics was investigated and the results obtained indicate its possible use as a new and interesting cell delivery system for bone tissue engineering and regenerative medicine applications.

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Síntesis y caracterización de un compuesto semiconductor NiO-ZnO dopado con nanopartículas de Au por el método sol-gel para aplicación como sensores de gas

Revista ECIPeru ◽

10.33017/reveciperu2012.0002/ ◽

2019 ◽

pp. 5-10 ◽

Cited By ~ 1

Keyword(s):

Spin Coating ◽

Gas Sensing ◽

Zinc Acetate Dihydrate ◽

Sol Gel ◽

Silicon Substrates ◽

Chloroauric Acid ◽

Porous Films ◽

Nickel Acetate Tetrahydrate ◽

Vis Spectroscopy ◽

Coating Method

Síntesis y caracterización de un compuesto semiconductor NiO-ZnO dopado con nanopartículas de Au por el método sol-gel para aplicación como sensores de gas Alex Díaz, Dionicio Otiniano, E. Della Gaspera, Alessandro Martucci Departamento de Ingeniería de Materiales, Universidad Nacional de Trujillo-Perú Dipartimento d’Ingegneria Meccanica – Settore Materiali, Universita di Padova, 35131 Padova-Italia DOI: https://doi.org/10.33017/RevECIPeru2012.0002/ RESUMEN Láminas porosas de un compuesto semiconductor formado por NiO-ZnO (%mol) dopado con nanopartículas de Au (3% mol) fueron preparados por el método sol-gel usando acetato de níquel tetrahidratado (NiC4H6O4.4H2O) y acetato de zinc dihidratado (C4H6O4Zn.2H2O) como precursores, metanol (CH6OH) y etanol (C2H6O) como solventes, monoetanolamina (C2H7NO) y dietanolamina (C4H11NO2) como ligantes funcionales, y ácido cloroaúrico HAuCl4 como precursor. Las muestras se caracterizaron por espectroscopias Infrarrojo (IR), ultravioleta (UV-VIS), microscopía SEM, difracción de rayos X (XRD), y ensayos de sensores gaseosos. Las muestras semiconductoras fueron depositadas sobre substratos de silicio por el método de spin-coating a 2000 rpm, posteriormente fueron tratadas a 500 y 600 ºC. Los efectos de las composiciones de NiO-ZnO y el porcentaje de dopaje también se discuten en este argumento. El espesor de la capa fue determinado por elipsometria aproximado a 75 nm. Estos compuestos fueron ensayados para sensores gaseosos de H2 y CO (1% V/V) a 300ºC, demostrando óptimos resultados para el H2, pero no así para el CO. Descriptores: NiO, ZnO, semiconductores, sensor gaseoso. ABSTRACT Porous films formed by a semiconductor ZnO-NiO (% mol) doped with Au nanoparticles (3% mol) were prepared by sol-gel method using nickel acetate tetrahydrate (NiC4H6O4.4H2O) and zinc acetate dihydrate (C4H6O4Zn.2H2O) as precursors, methanol (CH6OH) and ethanol (C2H6O) as solvents, monoethanolamine (C2H7NO) and diethanolamine (C4H11NO2) as functional chelants, and chloroauric acid (HAuCl4) as gold precursor. The samples were characterized by infrared (IR) and ultraviolet (UV-VIS) spectroscopy, microscopy SEM, X-ray diffraction (XRD) and gas sensing tests. The semiconductor samples were deposited on silicon substrates by spin-coating method at 2000 rpm, subsequently annealing at 500 and 600 °C. The effects of the compositions of NiO-ZnO and the percentage of doping are also discussed. The layer thickness was determined by ellipsometry in approximately 75 nm. These compounds were tested for gas sensors for H2 and CO (1% V/V) at 300 °C, showing excellent results for H2, but not for the CO. Keywords: NiO, ZnO, semiconductors, gas sensor.

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SiO2-SnO2:Er3+ Glass-Ceramic Monoliths

10.20944/preprints201807.0081.v1 ◽

2018 ◽

Author(s):

Lam Thi Ngoc Tran ◽

Damiano Massella ◽

Lidia Zur ◽

Alessandro Chiasera ◽

Stefano Varas ◽

...

Keyword(s):

Rare Earth ◽

Optical Sensors ◽

Tin Dioxide ◽

Sol Gel ◽

Glass Ceramics ◽

Building Blocks ◽

Spectroscopic Properties ◽

Silica Matrix ◽

Rare Earth Ions ◽

Planar Waveguides

The development of efficient luminescent systems, such as microcavities, solid state lasers, integrated optical amplifiers, optical sensors is the main topic in glass photonics. The building blocks of these systems are glass-ceramics activated by rare earth ions because they exhibit specific morphologic, structural and spectroscopic properties. Among various materials that could be used as nanocrystals to be imbedded in silica matrix, tin dioxide presents some interesting peculiarities, e.g. the presence of tin dioxide nanocrystals allows increase in both solubility and emission of rare earth ions. Here, we focus our attention on Er3+ - doped silica – tin dioxide photonic glass-ceramics fabricated by sol-gel route. Although the SiO2-SnO2:Er3+ could be fabricated in different geometrical systems: thin films, monoliths and planar waveguides we herein limit ourselves to the monoliths. The effective role of tin dioxide as luminescence sensitizer for Er3+ ions is confirmed by spectroscopic measurements and detailed fabrication protocols are discussed.

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