Sol-Gel Derived Pyroelectric Barium Strontium Titanate Thin films for Infrared Detector Applications

2000 ◽  
Vol 655 ◽  
Author(s):  
Jian-Gong Cheng ◽  
Jun Tang ◽  
Shao-Ling Guo ◽  
Jun-Hao Chu
Keyword(s):  
Thin Films ◽  
Electrode Materials ◽  
Infrared Detector ◽  
Sol Gel ◽  
Precursor Solution ◽  
Columnar Structure ◽  
Silicon Substrates ◽  
Layer By Layer ◽  
Individual Layer ◽  
Sol Gel Process

AbstractBa0.8Sr0.2TiO3 thin films that are suitable for infrared detector applications have been prepared with a sol-gel process using a highly diluted precursor solution. Columnar structure with grain size close to 200 nm was obtained with layer-by-layer homoepitaxy due to a very small thickness of individual layer. The measured pyroelecrtic coefficient is larger than 3.1×10划4 C/m2K at the temperatures ranging from 10 to 26 °C and reaches the maximum value of 4.1×10划4 C/m2K at 16.8 °C. The infrared detectivity of 4.6×107 cmHz1/2W划1 has been obtained at 19 °C and 10 Hz in the Ba0.8Sr0.2TiO3 films deposited on thick (500 μm) platinum coated silicon substrates. The better infrared response can be expected by the improvement in the thermal isolation of pyroelectric element and the electrode materials.

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

1999 ◽  
Vol 606 ◽  
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.

Novel Electrode Materials for Ultracapacitors:Structural and Electrochemical Properties of Sol-Gel-Derived Manganese Dioxide Thin Films

1999 ◽  
Vol 575 ◽  
Author(s):  
Suh-Cern Pang ◽  
MarcA Anderson
Keyword(s):  
Thin Films ◽  
Specific Capacitance ◽  
Electrode Materials ◽  
Sol Gel ◽  
High Specific Capacitance ◽  
Potential Range ◽  
Proton Mobility ◽  
Reversible Redox ◽  
Sol Gel Process ◽  
Nickel Substrates

ABSTRACTNanoparticulate MnO2thin films fabricated by the sol-gel process have been shown to be an outstanding novel electrode material for Ultracapacitors. The average specific capacitance of sol-gel-derived MnO2thin-films on nickel substrates as determined by cyclic voltammetry ranged from 566 to 698 F/g. These films also exhibited good cycling stability within the potential range of 0.0-0.9V (vs SCE) in unbuffered aqueous electrolyte. Both CV and XPS studies showed that MnO2films have remained chemically and structurally intact after 1,500 cycles. The XRD spectra and SEM micrographs showed that the microstructure of MnO2thin films are highly porous, and poorly crystalline or amorphous in nature. The high specific capacitance of MnO2may be predominantly due to pseudocapacitance associated with homogenous and reversible redox reactions of proton insertion into and out of the MnO2lattice. Any variation in the microstructure and thickness of films might affect proton mobility within the oxide matrix and thereby affecting their cycling behaviors. Further optimization of the cycling behaviors is envisaged with better microstructural and thickness control of these sol-gelderived nanoparticulate MnO2thin films.

Characterisation of Ferroelectric Lithium Tantalate Thin Films Prepared by a Sol-Gel Process

1993 ◽  
Vol 321 ◽  
Author(s):  
Chianping Ye ◽  
Paul Baude ◽  
Dennis L. Polla
Keyword(s):  
Thin Films ◽  
Curie Temperature ◽  
Single Crystal ◽  
Silicon Substrate ◽  
Ferroelectric Properties ◽  
Sol Gel ◽  
Precursor Solution ◽  
Pyroelectric Coefficient ◽  
Crystal Silicon ◽  
Sol Gel Process

ABSTRACTThin LiTaO3 films were prepared by spin coating of polymerized sol-gel precursor solution. Films have been deposited on single crystal silicon substrate, Ti/Pt or SiO2 coated silicon substrate. Films were characterized by x-ray diffraction, dielectric and pyroelectric Measurements. High Curie temperature (above 550 °C) was assumed for LiTaO3 thin films from the temperature dependence of dielectric constant. Replacing 35% of tantalum by titanium atoms in the LiTaO3 precursor solution has resulted the thin films with Curie temperature of 330 °C. The lower Curie temperature leads to the larger pyroelectric coefficient at room-temperature, which is more than double that of the undoped LiTaO3 thin films. The dielectric, pyroelectric, and ferroelectric properties have been compared to the single crystal LiTaO3 and ceramic Li0.91Ta0.73Ti0.36O3. LiTaO3 thin films are available by sol-gel process at low temperature, and their properties may possibly be controlled by varying the composition of the sol-gel precursor solution.

Novel thin films of titanium dioxide particles synthesized by a sol-gel process

1995 ◽  
Vol 10 (12) ◽  
pp. 3068-3078 ◽  
Author(s):  
V.J. Nagpal ◽  
R.M. Davis ◽  
S.B. Desu
Keyword(s):  
Thin Films ◽  
Titanium Dioxide ◽  
Sol Gel ◽  
Particle Surface ◽  
Composite Films ◽  
Visible Region ◽  
Silicon Substrates ◽  
Transparent Films ◽  
Sol Gel Process ◽  
Crystalline Films

Novel thin films of ultrafine titanium dioxide particles dispersed in a matrix of hydroxypropylcellulose (HPC) polymer have been made on quartz and silicon substrates. The titanium dioxide particles were made by the hydrolysis and condensation of titanium tetraethoxide (TEOT) in solutions of HPC in a mixture of ethanol and water. HPC controlled the particle size by adsorbing at the particle surface during the growth process and generating repulsive steric forces. The TiO2/HPC composite films were transparent in the visible region and completely blocked ultraviolet radiation at 300 nm. These films were crack-free and uniform in composition and thickness. Transparent films of amorphous TiO2 were made by burning out the HPC at 500 °C. These films were highly uniform and had no macroscopic cracks. X-ray diffraction revealed a transition to the anatase form upon sintering at 600 °C. A film sintered at 700 °C had a porosity of 38%. The crystalline films remained transparent until they densified at 800 °C.

Preparation of LiTaO3 Nano-Crystalline Films by Sol-Gel Process

2012 ◽  
Vol 531-532 ◽  
pp. 446-449 ◽  
Author(s):  
Jun Gou ◽  
Jun Wang ◽  
Ze Hua Huang ◽  
Ya Dong Jiang
Keyword(s):  
Thin Films ◽  
High Performance ◽  
Detection System ◽  
Sol Gel ◽  
Precursor Solution ◽  
Film Material ◽  
Nano Crystalline ◽  
Sol Gel Process ◽  
Crystalline Films ◽  
P Type

Lithium tantalite (LiTaO3) thin film material shows good feasibility and potential for the application of high-performance detection system. In this paper, sol-gel process of LiTaO3 thin films on p-type (111) silicon substrates was described. Stable precursor solution with a desired viscosity was obtained using lithium acetate (LiAc) and tantalum ethoxide (Ta(OC2H5)5) as starting materials. Heat treatment process was optimized to fabricate LiTaO3 films of high crystallinity. Higher crystalline quality films were obtained when each spin-coating process was followed by an annealing operation. Microstructures and crystallization properties of LiTaO3 thin films were further studied. Nano-crystalline films were obtained after annealing at 700 °C for 5 min. The experimental results indicated that the crystallinity and mean grain size of LiTaO3 thin films were proportional to the film thickness.

Effects of Individual Layer Thickness on the Structure and Electrical Properties of Sol-Gel-Derived Ba0.8Sr0.2TiO3 Thin Films

2012 ◽  
Vol 621 ◽  
pp. 23-26
Author(s):  
Wei Rao ◽  
Ding Guo Li ◽  
Hong Chun Yan
Keyword(s):  
Thin Films ◽  
Dielectric Constant ◽  
Layer Thickness ◽  
Sol Gel ◽  
Layer By Layer ◽  
Individual Layer ◽  
Individual Layer Thickness ◽  
Columnar Grains ◽  
The Individual ◽  
20 Nm

Ba0.8Sr0.2TiO3 thin films were prepared with various individual layer thicknesses using a sol– gel process. The individual layer thickness strongly affected the structure, ferroelectricity, and dielectric properties of the films. The films prepared with an individual layer thickness of 60 nm showed small equiaxed grains, cubic structure, temperature-independent dielectric constant, and no ferroelectricity. The films prepared with an individual layer thickness of 8 nm showed columnar grains, tetragonal structure, good ferroelectricity, and two dielectric peaks in the dielectric constant–temperature curve. The individual layer thickness for layer-by-layer homoepitaxy growth that resulted in columnar grains was <20 nm.

SCANNING ELECTRON MICROSCOPE AND X-RAY DIFFRACTION STUDIES ON THE LATTICE CONSTANT OF SPIN-COATED Zn1-xMgxO THIN FILMS OF SOL-GEL METHOD

2005 ◽  
Vol 12 (04) ◽  
pp. 605-610 ◽  
Author(s):  
M. RUSOP ◽  
K. UMA ◽  
T. SOGA ◽  
T. JIMBO
Keyword(s):  
Thin Films ◽  
Lattice Constant ◽  
Zinc Acetate Dihydrate ◽  
Sol Gel ◽  
Zno Films ◽  
Silicon Substrates ◽  
Acetate Dihydrate ◽  
Glass Substrates ◽  
Sol Gel Process ◽  
Coating Method

ZnO and Zn 1-x Mg x O thin films were prepared on glass and silicon substrates by spin coating method using 2-methoxyethanol solution of zinc acetate dihydrate and magnesium acetate dihydrate stabilized by monoethanolamine. The effects of drying and annealing condition of structural and optical properties of the films were studied. It was found that the samples annealed at 650°C improves the crystallographic orientation of the ZnO films grown by the sol-gel process significantly. Two types of substrates were used to examine the substrate effects of the growth of Zn 1-x Mg x O thin films. In corning glass substrates, the lattice constant decreased by a little with increasing concentration of Mg , whereas in the case of silicon substrates, the lattice constant decreased rapidly with x when compared to the glass substrates. The optical band energy gaps of Zn 1-x Mg x O thin films were slightly increased with increasing concentration of Mg .

Preparation and Characterization of Pb(Zr0.52Ti0.48)O3 Powders and Thin Films by a Sol-gel Route

2000 ◽  
Vol 15 (6) ◽  
pp. 1336-1341 ◽  
Author(s):  
Dage Liu ◽  
Hongxi Zhang ◽  
Zhong Wang ◽  
Liancheng Zhao
Keyword(s):  
Thin Films ◽  
Lead Zirconate Titanate ◽  
Lead Acetate ◽  
Sol Gel ◽  
Precursor Solution ◽  
Lead Zirconate ◽  
Tetrabutyl Titanate ◽  
Sol Gel Process ◽  
High Fatigue

Lead zirconate titanate [Pb(ZrxTi1−x)O3 (PZT)] powders and ferroelectric thin films with a composition near the morphotropic phase boundary [Pb(Zr0.52Ti0.48)O3] were prepared by a modified sol-gel process using zirconium oxynitrate-2-hydrate as the zirconium source and ethylene glycol as solvent. The precursor solution was prepared from lead acetate-3-hydrate, tetrabutyl titanate, and zirconium oxynitrate-2-hydrate. Perovskite PZT powders were obtained after sintering at 450 °C for 2 h. Films rapid-thermally annealed at 650 °C for 1 min formed well-crystallized perovskite.Microstructures of these films indicated the presence of nano-sized grains (∼50 nm). The remnant polarization was 28.5 μC/cm2, and the coercive field was 39.8 kV/cm. Ferroelectric polarization fatigue test of In/PZT/Pt/Ti/SiO2/Si showed a high fatigue resistance up to 3 × 1010 cycles before Pr decreased by 50%.

Preparation of highly oriented Pb(Zr0.52Ti0.48)O3 thin films by sol-gel-hydrothermal process

1999 ◽  
Vol 14 (7) ◽  
pp. 2712-2715 ◽  
Author(s):  
Jianming Zeng ◽  
Chenglu Lin ◽  
Jinhua Li ◽  
Kun Li
Keyword(s):  
Thin Films ◽  
Sol Gel ◽  
Hydrothermal Process ◽  
Silicon Substrates ◽  
Rocking Curve ◽  
Force Microscopy ◽  
Low Leakage ◽  
Atomic Force ◽  
Low Leakage Current ◽  
Sol Gel Process

A novel sol-gel-hydrothermal process for preparation of highly oriented thin films of Pb(Zr0.52Ti0.48)O3 is reported. Pb(Zr0.52Ti0.48)O3 thin films with fully (111) orientation were successfully prepared on platinized silicon substrates at low temperature (100–200 °C) by combining a conventional sol-gel process and hydrothermal method, i.e., sol-gel-hydrothermal technique. The x-ray rocking curve for the (111) reflection as measured by a high-resolution four-crystal diffractrometer showed a narrow full width at half-maximum value of 0.20° for the as-prepared films. A dense, pinhole-free, and uniform surface morphology was observed from atomic force microscopy images of the films. The low leakage current density of the prepared films was also found.

The crystallization of thin-film ceramics

1992 ◽  
Vol 50 (1) ◽  
pp. 338-339
Author(s):  
J.M. Schwartz ◽  
L.F. Francis ◽  
L.D. Schmidt ◽  
P.S. Schabes-Retchkiman
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Sol Gel ◽  
Processing Route ◽  
Small Areas ◽  
Ceramic Thin Films ◽  
Complex Shapes ◽  
Sol Gel Process ◽  
Ceramic Precursors ◽  
Crystalline Ceramic

Ceramic thin films and coatings are of interest for electrical, optical, magnetic and thermal barrier applications. Critical for improved properties in thin films is the development of specific microstructures during processing. To this end, the sol-gel method is advantageous as a versatile processing route. The sol-gel process involves depositing a solution containing metalorganic or colloidal ceramic precursors onto a substrate and heating the deposited layer to form a crystalline or non-crystalline ceramic coating. This route has several advantages, including the ability to create tailored microstructures and properties, to coat large or small areas, simple or complex shapes, and to more easily prepare multicomponent ceramics. Sol-gel derived coatings are amorphous in the as-deposited state and develop their crystalline structure and microstructure during heat-treatment. We are particularly interested in studying the amorphous to crystalline transformation, because many key features of the microstructure such as grain size and grain size distribution may be linked to this transformation.

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