Effect of annealing on fluorescence of Ce3+-doped silica prepared by sol-gel process

2000 ◽  
Vol 15 (11) ◽  
pp. 2364-2367 ◽  
Author(s):  
H. J. Bi ◽  
W. P. Cai ◽  
H. Z. Shi ◽  
L. D. Zhang ◽  
B. D. Yao
Keyword(s):  
Vapor Deposition ◽  
Annealing Temperature ◽  
Sol Gel ◽  
Structural Evolution ◽  
Chemical Vapor ◽  
Emission Peak ◽  
Silica Network ◽  
Oh Groups ◽  
Sol Gel Process ◽  
Different Temperatures

We prepared Ce3+-doped silica by the sol-gel method and studied the effect of annealing on fluorescence of these samples. Different fluorescence was observed for samples annealed at different temperatures, changing gradually from solution like fluorescence to fluorescence similar to that observed in the Ce3+-doped silica prepared by chemical vapor deposition. It was found that the emission intensity first decreased with increasing annealing temperature until 500 °C, and then increased with the temperature ranging from 500 to 950 °C. Meanwhile, the emission peak showed a large red shift and an obvious broadening. These changes were attributed to the annealing-induced structural evolution in silica: Ce3+ ions changed from coordinating with water and terminal OH-groups to embedding in silica network.

Phase-Separated Inorganic-Organic Hybrids for Microelectronic Applications

MRS Bulletin ◽  
1997 ◽  
Vol 22 (10) ◽  
pp. 44-48 ◽  
Author(s):  
R.D. Miller ◽  
J.L. Hedrick ◽  
D.Y. Yoon ◽  
R.F. Cook ◽  
J.P. Hummel
Keyword(s):  
Chemical Vapor Deposition ◽  
Silicon Dioxide ◽  
Vapor Deposition ◽  
Sol Gel ◽  
Chemical Vapor ◽  
Dielectric Constants ◽  
Capacitive Coupling ◽  
Condensation Polymerization ◽  
Sol Gel Process ◽  
On Chip

As on-chip device densities increase and active device dimensions shrink, signal delays and noise increase due to capacitive coupling and crosstalk between the metal interconnections. Since delays, noise, and power consumption all depend critically on the dielectric constant of the separating insulator, much attention has focused recently on replacing standard silicon dioxide with new intermetal dielectrics (IMDs) having dielectric constants considerably lower than conventional oxide (k = 3.9–4.2). On-chip silicon dioxide insulators are currently deposited by gas-phase techniques such as chemical vapor deposition or plasma-enhanced chemical vapor deposition. Silicate films may also be formed at lower temperatures by sol-gel procedures. In the sol-gel process, typically an orthosilicate ester is hydrolyzed with water. This often occurs in an organic solvent to form a soluble, partially condensed polymer (sol) that can be spun on a substrate to produce a solvent-containing film. Subsequent solvent removal and curing results in the silicate film. The process involves hydrolysis to generate polyfunctional silanols followed by condensation polymerization to eventually yield a gel. Since both processes involve the substantial loss of volatile materials, considerable shrinkage occurs (75–85% is typical). Inhomogeneity of shrinkage or shrinkage on constraining substrates can often lead to cracking unless the films are very thin (often <1 μm). In the sol-gel process, a variety of techniques are employed to avoid capillary-driven cracking forces, including (1) very slow drying, (2) drying with supercritical fluids, or (3) chemically controlled condensation.

Fabrication and Optical Characteristics of a Novel Optical Fiber Doped with the Au Nanoparticles

2006 ◽  
Vol 6 (11) ◽  
pp. 3555-3558 ◽  
Author(s):  
Seongmin Ju ◽  
Viet Linh Nguyen ◽  
Pramod R. Watekar ◽  
Bok Hyeon Kim ◽  
Chaehwan Jeong ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Surface Plasmon Resonance ◽  
Optical Fibers ◽  
Vapor Deposition ◽  
Au Nanoparticles ◽  
Sol Gel ◽  
Chemical Vapor ◽  
Tetraethyl Orthosilicate ◽  
Sol Gel Process ◽  
Gold Metal

Optical fibers containing gold metal nanoparticles were developed by modified chemical vapor deposition, in which Au(OH)3 and tetraethyl-orthosilicate (TEOS) was used via sol–gel process to incorporate gold metals by providing the reduction atmosphere. The absorption peak appeared near 490 nm was found to be due to the surface plasmon resonance of the gold nanoparticles incorporated in the fiber core.

scholarly journals Functionalization of Si-C Using TEOS (Tetra Ethyl Ortho Silica) as Precursor and Organic Catalyst

2020 ◽  
Vol 148 ◽  
pp. 07008 ◽  
Author(s):  
Riani Ayu Lestari ◽  
Muthia Elma ◽  
Erdina Lulu Atika Rampun ◽  
Anna Sumardi ◽  
Adhe Paramitha ◽  
...  
Keyword(s):  
Citric Acid ◽  
Sol Gel ◽  
Acid Catalyst ◽  
Silica Xerogel ◽  
Silica Network ◽  
Infrared Band ◽  
Oh Groups ◽  
Structured Materials ◽  
Sol Gel Process ◽  
Organic Catalyst

Silica network was tailored configuring siloxane (Si-O-Si) and silanol (Si-OH) groups which are essential to produce porous-structured materials. As silanols are hydrophilic, react with water to form fouling. This research address to actualize strategy for synthesizing highly functionalized silica carbon (Si-C) using hybrid organic-inorganic structures as the primary method for improving hydro-stability by employing precursor TEOS and organic catalyst through a sol-gel process. Catalysis employs citric acid or citric acid-ammonia whereas carbon templated into silica network. The synthesis scheme involves: a) sol-gel process at 0°C and b) calcination. Silica sol dried into xerogels were prepared and calcined at 200°C and 250°C. Characterization of xerogels showed the infrared band areas of the organic groups to evaluate the thermal stability. For xerogel employed single (pH 5.5) and dual (pH 7.65) catalyst, infrared spectra showed mostly look similar Si-C area at similar wavelength. Silica xerogel is more effectively prepared from TEOS with one-step single acid catalyst including calcination.

Effect of Annealing temperature on the Structural and Magnetic Properties of TbxY3-xFe5O12(x = 0.0, 1.0, 2.0) Thin Films Prepared by Sol-Gel Process

2012 ◽  
Vol 501 ◽  
pp. 236-241 ◽  
Author(s):  
Ftema W. Aldbea ◽  
Noor Bahyah Ibrahim ◽  
Mustafa Hj. Abdullah ◽  
Ramadan E. Shaiboub
Keyword(s):  
Thin Films ◽  
Magnetic Properties ◽  
Room Temperature ◽  
Annealing Temperature ◽  
Sol Gel ◽  
Vibrating Sample Magnetometer ◽  
X Ray ◽  
Garnet Phase ◽  
Sol Gel Process ◽  
Amorphous Structures

Thin films nanoparticles TbxY3-xFe5O12 (x=0.0, 1.0, 2.0) were prepared by the sol-gel process followed by annealing process at various annealing temperatures of 700° C, 800° C and 900° C in air for 2 h. The results obtained from X-ray diffractometer (XRD) show that the films annealed below 900°C exhibit peaks of garnet mixed with small amounts of YFeO3 and Fe2O3. Pure garnet phase has been detected in the films annealed at 900°C. Before annealing the films show amorphous structures. The particles sizes measurement using the field emission scanning electron microscope (FE-SEM) showed that the particles sizes increased as the annealing temperature increased. The magnetic properties were measured at room temperature using the vibrating sample magnetometer (VSM). The saturation magnetization (Ms) of the films also increased with the annealing temperature. However, different behavior of coercivity (Hc) has been observed as the annealing temperature was increased.

scholarly journals Structural and Magnetic Properties of Ni81Fe19Thin Film Grown on Si(001) Substrate via Single Graphene Layer

2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Gui-fang Li ◽  
Shibin Liu ◽  
Shanglin Yang ◽  
Yongqian Du
Keyword(s):  
Thin Films ◽  
Magnetic Properties ◽  
Vapor Deposition ◽  
Graphene Layer ◽  
Structural Investigation ◽  
Annealing Temperature ◽  
Chemical Vapor ◽  
Magnetic Thin Films ◽  
Structural And Magnetic Properties

We prepared magnetic thin films Ni81Fe19on single-crystal Si(001) substrates via single graphene layer through magnetron sputtering for Ni81Fe19and chemical vapor deposition for graphene. Structural investigation showed that crystal quality of Ni81Fe19thin films was significantly improved with insertion of graphene layer compared with that directly grown on Si(001) substrate. Furthermore, saturation magnetization of Ni81Fe19/graphene/Si(001) heterostructure increased to 477 emu/cm3with annealing temperatureTa=400°C, which is much higher than values of Ni81Fe19/Si(001) heterostructures withTaranging from 200°C to 400°C.

Development of temporal spectroscopic properties for Xerogel matrices doped with Rhodamine 6G dye

Open Physics ◽  
2006 ◽  
Vol 4 (3) ◽  
Author(s):  
Abbas Al-Wattar ◽  
Baha Chiad ◽  
Wesam Twej ◽  
Sarmed Al-Awadi
Keyword(s):  
Fluorescence Spectra ◽  
Rhodamine 6G ◽  
Sol Gel ◽  
Blue Shift ◽  
Spectroscopic Properties ◽  
Dye Molecules ◽  
Absorption And Fluorescence Spectra ◽  
Silica Network ◽  
Sol Gel Process ◽  
Two Parameters

AbstractThe solid host of a laser dye modifies its spectroscopic properties with respect to its liquid host. During the Sol-Gel process the dye molecules suffer from changing their environment. Two parameters affect this matter, the change in the concentration due to the evaporation of the solvent (drying) and the caging of dye molecules inside the pores or attachment to the silica network. Rhodamine 6G absorption and fluorescence spectra with different concentrations, during Sol-Gel time processing, have been studied. Both, absorption and fluorescence spectra of the dye in the solid host, for different concentrations, show a blue-shift relative to its liquid phase.

Temperature-Induced Structure and Morphological Transformation in SnS Prepared by a Chemical Vapor Deposition Method

2014 ◽  
Vol 513-517 ◽  
pp. 286-290 ◽  
Author(s):  
Ren Fu Zhuo ◽  
Yi Nong Wang ◽  
De Yan ◽  
Xiao Yong Xu ◽  
Zhi Guo Wu
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Chemical Vapor Deposition Method ◽  
Morphological Transformation ◽  
Simple Chemical ◽  
Different Temperatures ◽  
Sns Thin Films ◽  
Induced Structure ◽  
Made In

SnS thin films were deposited at different temperatures on silicon and quartz plates through directly elementary reaction via a simple chemical vapor deposition (CVD) process. The as-prepared products have a transformation of morphology from plate-like to granule-like when the temperature increased. A mechanism involving two competitive factors, surface energy and binding energy, was proposed to understand their growth. The products prepared at low temperature were single crystal while the films made in high temperature are polycrystal, the optical band gap (1.2~2.1ev) and the Sn:S atom ratios increases as the deposited temperature increases.

Preparation and Microwave Permittivity of Nano-Sized Si/C/N Powder

2005 ◽  
Vol 475-479 ◽  
pp. 3571-3574 ◽  
Author(s):  
Xiao Kui Liu ◽  
Wan Cheng Zhou ◽  
Fa Luo ◽  
Dong Mei Zhu
Keyword(s):  
Nitrogen Content ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Dissipation Factor ◽  
Nano Powder ◽  
Heat Treated ◽  
Different Temperatures ◽  
Degree Of Crystallization ◽  
Microwave Permittivity ◽  
N Powder

Nano-sized Si/C/N powders are prepared from hexamethyldisilazane ((CH3)3Si)2NH) by chemical vapor deposition (CVD) at different pyrolysis temperatures from 900°C to 1200°C. The as-formed Si/C/N nano powder is amorphous, and after controlled heat-treatment, SiC crystals formed. The composition of the Si/C/N powders prepared at different conditions is analyzed and the result shows that the nitrogen content of the Si/C/N powder is related to the synthesizing temperature. Si/C/N powders heat-treated at different temperatures are mixed with paraffin wax and the microwave permittivity of the mixture is measured. The result shows that the e¢, e², and the dissipation factor tg d ( e²/ e¢) of the mixture are high at the frequency of 8.2~12.4GHz, and the nitrogen content and the degree of crystallization have influence on the microwave permittivity. We believe that the high value of e¢, e² ,and tg d are due to the dielectric relaxation as the result of nitrogen atoms doped in silicon carbide lattice.

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