Effect of Supercritical Drying on Sol-Gel Deposited Silica Aerogel Thin Films at Different Temperatures

2014 ◽  
pp. 13-16
Author(s):  
Anil Gaikwad ◽  
Yogesh Mhaisagar ◽  
Jigar Bhavsar ◽  
Ashok Mahajan
Keyword(s):  
Thin Films ◽  
Silica Aerogel ◽  
Sol Gel ◽  
Supercritical Drying ◽  
Different Temperatures

New Transparent Substrate with Silica Aerogel Film for Surface-Emissive Devices

2000 ◽  
Vol 660 ◽  
Author(s):  
H. Yokogawa ◽  
K. Kawano ◽  
M. Yokoyama ◽  
T. Tsutsui ◽  
M. Yahiro ◽  
...  
Keyword(s):  
Refractive Index ◽  
Glass Substrate ◽  
Silica Aerogel ◽  
Sol Gel ◽  
Supercritical Drying ◽  
Transparent Electrode ◽  
Light Sources ◽  
Photoluminescence Intensity ◽  
Transparent Substrate ◽  
Low Refractive Index

ABSTRACTSilica aerogels prepared by sol-gel methods with supercritical drying process have transparency and extremely low refractive index which is not available in any other materials. This extraordinary refractivity is expected to present some new features as an optical material. Ordinarily, coupling-out efficiency of surface-emissive light sources has been assumed to be low. It is due to the losses organized from internal reflection of emitted light at the air-glass interface and dissipation during wave-guiding propagation within the substrate.However, when material that has extremely low refractive index is inserted between a thin luminescence layer and glass substrate, almost all the light from the luminescence layer can efficiently couple out to air passing through the glass substrate. In this report, we introduce a silica aerogel film as a low refractive index material for surface-emissive devices, such as photoluminescent and electroluminescent device. In the experiments, the photoluminescence intensity of Alq3 through the silica aerogel layer was twice as large as that of the glass substrate without the silica aerogel film. Moreover, we formed a new substrate which contained a transparent electrode on the silica aerogel film. Using this substrate, we fabricated the OLED and observed the disappearance of wave-guiding propagation within the glass substrate.

LUMINESCENT PROPERTIES OF SOL-GEL DEPOSITED Eu:TiO2 THIN FILMS

2001 ◽  
Vol 15 (17n19) ◽  
pp. 769-773 ◽  
Author(s):  
M. GARCIA-ROCHA ◽  
A. CONDE-GALLARDO ◽  
I. HERNANDEZ-CALDERON ◽  
R. PALOMINO-MERINO
Keyword(s):  
Thin Films ◽  
Sol Gel ◽  
Luminescent Properties ◽  
X Ray Diffraction ◽  
Si Substrates ◽  
Glass Substrates ◽  
Corning Glass ◽  
Different Temperatures ◽  
Hecd Laser

In this work we show the results on tile growth and optical characterization of TiO 2 thin films doped with Eu atoms. Eu:TiO2 films were grown at room temperature with different Eu concentrations by sol-gel on Si Corning glass substrates. A different crystalline structure is developed for the films deposited on Corning glass than those deposited on Si as observed from x-ray diffraction experiments. Room and low temperature photoluminescence (PL) was measured by using two different lines (325 and 442 nm) of a HeCd laser. A strong PL signal associated to the 5 D 0→7 F 2 transition from Eu +3 was observed. A better emission was obtained from those films deposited on Si substrates, Finally, the evolution of the PL signal is studied when the samples are annealed at different temperatures in O 2 atmosphere.

Effect of Annealing Atmosphere on the Morphology of Copper Oxide Thin Films Deposited on TiO2 Substrates Prepared by Sol-Gel Process

2013 ◽  
Vol 594-595 ◽  
pp. 113-117 ◽  
Author(s):  
Dewi Suriyani Che Halin ◽  
Ibrahim Abu Talib ◽  
Abdul Razak Daud ◽  
Muhammad Azmi Abdul Hamid
Keyword(s):  
Thin Films ◽  
Surface Roughness ◽  
Grain Size ◽  
Copper Oxide ◽  
Spin Coating ◽  
Sol Gel ◽  
Annealing Atmosphere ◽  
Oxide Thin Films ◽  
Different Temperatures ◽  
Xrd Patterns

Copper oxide films were prepared via sol-gel like spin coating starting from methanolic solutions of cupric chloride onto the TiO2 substrates. Films were obtained by spin coating under room conditions (temperature, 25-30 °C) and were subsequently annealed at different temperatures (200-400 °C) in oxidizing (air) and inert (N2) atmospheres. X-ray diffraction (XRD) patterns showed crystalline phases, which were observed as a function of the annealing conditions. The film composition resulted single or multi-phasic depending on both temperature and atmosphere. The grain size of film was measured using scanning electron microscopy (SEM) and the surface roughness of thin films was characterized by atomic force microscopy (AFM). The grain size of which was annealed in air at 300 °C was 30.39 nm with the surface roughness of 96.16 nm. The effects of annealing atmosphere on the structure and morphology of copper oxide thin films are reported.

Effects of Buffer Layer on the Fabrication and Characteristics of Ferroelectric Thin Films

1997 ◽  
Vol 493 ◽  
Author(s):  
Han Wook Song ◽  
Joon Sung Lee ◽  
Dae-Weon Kim ◽  
Kwang Ho Kim ◽  
Tae-Hyun Sung ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Buffer Layer ◽  
Sol Gel ◽  
Optimum Thickness ◽  
Si Substrate ◽  
Barrier Effects ◽  
Pzt Thin Film ◽  
Different Temperatures ◽  
Gel Technique

ABSTRACTMgO thin films were deposited on Si(100) substrate with different temperatures from 500 °C to 800 °C and different e-beam powers from 25W to 100W using e-beam evaporation method. Pb(Zr0.53Ti0.47)O3(PZT) thin films were deposited on MgO/Si(100) substrates with different drying temperatures from 190 °C to 310 °C using sol-gel technique. If there were no buffer layer between the PZT thin film and Si substrate, the peaks corresponding to perovskite PZT phase were not observed. However the buffer layer were inserted between the PZT thin film and Si substrate, it was possible to fabricate perovskite PZT phase. The barrier effects of MgO thin film to the interdiffusion of Pb were investigated by AES study. Optimum thickness of MgO at which PZT/MgO/Si structure shows P-E hysteresis was calculated, and the hysteresis was tested for PZT/MgO/Si structures with different MgO thicknesses.

scholarly journals Materials of Nanocrystalline Sr1-xBaxBi4Ti4O15 for Piezoelectric Sensor

2008 ◽  
Vol 55-57 ◽  
pp. 253-256 ◽  
Author(s):  
N. A. A. Manaf ◽  
Muhamad Mat Salleh ◽  
Muhammad Yahaya
Keyword(s):  
Thin Films ◽  
Sol Gel ◽  
Pressure Sensors ◽  
Piezoelectric Sensor ◽  
Titanium Butoxide ◽  
Loading Method ◽  
Different Temperatures ◽  
Dielectric Constant Measurement ◽  
Crystalline Nature ◽  
Source Materials

The nanocrystalline Strontium Barium Bismuth Titanate (SBBT) thin films with structure of Al/TiO2/SBBT/TiO2/RuO2/SiO2/Si were fabricated using sol-gel technique. The source materials are bismuth acetate Bi(CH3COO)2, barium acetate Bi(CH3COO)2, strontium acetate Sr(CH3COO)2 and titanium butoxide (Ti(OC4H9 )4). Different nanostructures of the films were prepared with un-annealed condition as well as after annealing at three different temperatures of 400, 500 and 6000C, in air for 2 minutes. The structure of SBBT thin films have been systematically studied by XRD, AFM, SEM and dielectric constant measurement. For the sensor device measurement, the SBBT thin film pressure sensors were tested by pneumatic loading method at pressure range between 0 to 450 kPa. It was found that the sensing properties of the films were affected by the crystalline nature of the films. It is shown that there is a linear relationship between the crystallization, grains size and dielectric properties with the sensing response of the film towards pressure.

STRUCTURAL AND OPTICAL INVESTIGATIONS ON NANOCRYSTALLINE TiO2 THIN FILMS PREPARED BY SOL–GEL SPIN COATING TECHNIQUE

2010 ◽  
Vol 09 (04) ◽  
pp. 355-358 ◽  
Author(s):  
T. S. SENTHIL ◽  
M. THAMBIDURAI ◽  
N. MUTHUKUMARASAMY ◽  
R. BALASUNDARAPRABHU
Keyword(s):  
Thin Films ◽  
Spin Coating ◽  
Anatase Phase ◽  
Sol Gel ◽  
Diffraction Method ◽  
Tio2 Thin Films ◽  
Nanocrystalline Tio2 ◽  
Glass Substrates ◽  
Coating Method ◽  
Different Temperatures

TiO2 thin films have been deposited onto well cleaned glass substrates by sol–gel spin coating method. The prepared TiO2 films have been annealed at different temperatures (350°C, 450°C and 550°C). The structural properties of the films have been studied using X-ray diffraction method and High Resolution Transmission Electron Microscope (HRTEM). The as-deposited films have been found to be amorphous in nature. The crystalline quality has been observed to improve with annealing temperature. The annealed TiO2 films have been found to exhibit anatase phase. The optical properties have been studied using transmittance spectrum.

Preparation and Characterization of Ultralow Density Silica Aerogels by Acetonitrile Supercritical Drying

2012 ◽  
Vol 519 ◽  
pp. 83-86 ◽  
Author(s):  
Guang Wu Liu ◽  
Xing Yuan Ni ◽  
Bin Zhou ◽  
Qiu Jie Yu
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Silica Aerogel ◽  
Sol Gel ◽  
Supercritical Drying ◽  
Silica Aerogels ◽  
High Specific Surface Area ◽  
Molar Ratio ◽  
Sol Gel Process

This paper deals with the synthesis of ultralow density silica aerogels using tetramethyl orthosilicate (TMOS) as the precursor via sol-gel process followed by supercritical drying using acetonitrile solvent extraction. Ultralow density silica aerogels with 6 mg/cc of density was made for the molar ratio by this method. The microstructure and morphology of the ultralow density silica aerogels was characterized by the specific surface area, SBET, SEM, and the pore size distribution techniques. The results show that the ultralow density silica aerogel has the high specific surface area of 812m2/g. Thermal conductivities at desired temperatures were analyzed by the transient plane heat source method. Thermal conductivity coefficients of silica aerogel monoliths changed from 0.024 to 0.043W/ (m K) as temperature increased to 400°C, revealed an excellent heat insulation effect during thermal process.

Hydrogen Gas Sensing Characterizations Based on Nanocrystalline SnO2 Thin Films Grown on SiO2/Si and Al2O3 Substrates

2017 ◽  
Vol 268 ◽  
pp. 244-248
Author(s):  
Abu Hassan Haslan ◽  
Imad Hussein Kadhim
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Gas Sensing ◽  
Sol Gel ◽  
Hydrogen Gas ◽  
Rutile Structure ◽  
Nanoparticle Distribution ◽  
Si Substrates ◽  
Coating Method ◽  
Different Temperatures

High-quality nanocrystalline (NC) SnO2 thin films were grown on SiO2/Si and Al2O3 substrates using sol–gel spin coating method. The structural properties, surface morphologies and gas sensing properties of the NC SnO2 were investigated. XRD measurements showed a tetragonal rutile structure and the diffraction peaks for NC SnO2 thin films grown on Al2O3 substrates outperformed those of NC SnO2 films grown on SiO2/Si substrates. The surface morphology of the annealed SnO2 thin films at 500 °C appeared as polycrystalline with uniform nanoparticle distribution. Hydrogen (H2) gas sensing performance of the NC SnO2 was examined for H2 concentrations ranging from 150 ppm to 1000 ppm at different temperatures (room temperature, 75 and 125 °C) for over 50 min. The room temperature sensitivities for H2 gas sensors based on NC SnO2 thin films grown on Al2O3 and SiO2/Si substrates was 2570% and 600%, respectively upon exposure to 1000 ppm of H2 gas. While the sensitivity values at 125 °C increased to 9200% and 1950%, respectively.

Phase transformations in sol-gel prepared PZT and PLT thin films upon isothermal treatments at different temperatures

1999 ◽  
Vol 225 (1) ◽  
pp. 271-278 ◽  
Author(s):  
S. B. Majumder ◽  
B. Roy ◽  
D. C. Agrawal ◽  
Y. N. Mohapatra
Keyword(s):  
Thin Films ◽  
Phase Transformations ◽  
Sol Gel ◽  
Different Temperatures

On the Microstructure and Electrical Properties of Undoped and Antimony- Doped Tin Oxide Thin Film Deposited by Sol-Gel Process

2007 ◽  
Vol 280-283 ◽  
pp. 835-838
Author(s):  
Gang Du ◽  
Dao Li Zhang ◽  
Lan Zhao ◽  
Jian Mei Xu ◽  
Dong Xiang Zhou
Keyword(s):  
Thin Films ◽  
Sheet Resistance ◽  
Tin Oxide ◽  
Sol Gel ◽  
Oxide Thin Film ◽  
X Ray Diffraction ◽  
Coated Glass Substrate ◽  
Sol Gel Process ◽  
Different Temperatures ◽  
Tin Oxide Films

Undoped and antimony-doped tin oxide (ATO) thin films were prepared by sol-gel process in the solution of metal salts of tin (II) chloride dehydrate and antimony tri-chloride. The microstructure of the thin films was analyzed by scanning electron microscope (SEM) and X-ray diffraction (XRD). Compared with undoped tin oxide, doped antimony tin oxide films coated glass substrate were homogeneous in composition and morphology after being sintered at different temperatures. Electrical behavior of the doped films was discussed in terms of sheet resistance measured by four point probe. From the experimental data, the sheet resistance of the films could be as low as 100-200Ω/□

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