scholarly journals Effect of Solution Conditions on the Properties of Sol–Gel Derived Potassium Sodium Niobate Thin Films on Platinized Sapphire Substrates

Nanomaterials ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1600 ◽  
Author(s):  
Alexander Tkach ◽  
André Santos ◽  
Sebastian Zlotnik ◽  
Ricardo Serrazina ◽  
Olena Okhay ◽  
...  
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Low Cost ◽  
Sol Gel ◽  
Precursor Solution ◽  
Dissipation Factor ◽  
Solution Concentration ◽  
Potassium Sodium Niobate ◽  
Sapphire Substrates ◽  
Average Grain Size

If piezoelectric micro-devices based on K0.5Na0.5NbO3 (KNN) thin films are to achieve commercialization, it is critical to optimize the films’ performance using low-cost scalable processing conditions. Here, sol–gel derived KNN thin films are deposited using 0.2 and 0.4 M precursor solutions with 5% solely potassium excess and 20% alkali (both potassium and sodium) excess on platinized sapphire substrates with reduced thermal expansion mismatch in relation to KNN. Being then rapid thermal annealed at 750 °C for 5 min, the films revealed an identical thickness of ~340 nm but different properties. An average grain size of ~100 nm and nearly stoichiometric KNN films are obtained when using 5% potassium excess solution, while 20% alkali excess solutions give the grain size of 500–600 nm and (Na + K)/Nb ratio of 1.07–1.08 in the prepared films. Moreover, the 5% potassium excess solution films have a perovskite structure without clear preferential orientation, whereas a (100) texture appears for 20% alkali excess solutions, being particularly strong for the 0.4 M solution concentration. As a result of the grain size and (100) texturing competition, the highest room-temperature dielectric permittivity and lowest dissipation factor measured in the parallel-plate-capacitor geometry were obtained for KNN films using 0.2 M precursor solutions with 20% alkali excess. These films were also shown to possess more quadratic-like and less coercive local piezoelectric loops, compared to those from 5% potassium excess solution. Furthermore, KNN films with large (100)-textured grains prepared from 0.4 M precursor solution with 20% alkali excess were found to possess superior local piezoresponse attributed to multiscale domain microstructures.

Structural and Optical Studies of Molarity Based ZnO Thin Films

2017 ◽  
Vol 17 ◽  
pp. 140-148 ◽  
Author(s):  
A. Jacquiline Regina Mary ◽  
S. Arumugam
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Visible Region ◽  
Precursor Solution ◽  
Hexagonal Wurtzite Structure ◽  
Solution Concentration ◽  
Molar Concentration ◽  
Zno Thin Films ◽  
Zno Films ◽  
Average Grain Size

Zinc Oxide thin films were prepared for different precursor solution molarities from 0.025M to 0.1M by spray pyrolysis deposition technique. A comprehensive study was carried out to realize the effect of concentration of precursor on ZnO thin films. The optimized temperature of the glass substrate was 300°C. From the XRD data it is inferred that the films are polycrystalline and hexagonal wurtzite structure . The degree of preferred orientation were along diffraction planes (100), (002) and (101) for all the ZnO films. The intensity of the diffraction peak prepared with 0.1M concentration is higher than those prepared at lower concentrations. The grain size (D) was calculated using Debye-Scherrer formula. It was found that the average grain size increases, when the molar concentration increases. As the solution concentration increases, the band gap decreases. The films are transparent in the visible region (85%), and the transmittance decreases as the molar concentration increases, which is caused by optical scattering at grain boundaries.

Sol-gel synthesis of textured lanthanum titanate thin films

2003 ◽  
Vol 18 (2) ◽  
pp. 357-362 ◽  
Author(s):  
Mary M. Sandstrom ◽  
Paul Fuierer
Keyword(s):  
Thin Films ◽  
Sol Gel ◽  
Precursor Solution ◽  
Solution Concentration ◽  
Optical Measurements ◽  
Layered Perovskite ◽  
Orientation Factor ◽  
Anisotropic Structures ◽  
Sol Gel Films ◽  
Sol Gel Synthesis

Control over crystallographic orientation in thin films is important, particularly with highly anisotropic structures. Because of its ferroelectric nature, the layered perovskite La2Ti2O7 has interesting piezoelectric and electrooptic properties that may be exploited when films are highly textured. Sol-gel films with an orientation factor of greater than 95% were fabricated without relying on epitaxial (lattice-matching) growth from the substrate. Film orientation and crystallization were confirmed by x-ray diffraction, scanning electron microscopy, atomic force microscopy, and optical measurements. The particle sizes in all precursor solutions were measured by dynamic light scattering experiments. Experimental results indicate that film orientation is a function of precursor solution concentration, size of the molecular clusters in the solution, and film thickness.

LiNiO2 Thin Films Fabricated by Diffusion of Li on Ni Tapes

2007 ◽  
Vol 336-338 ◽  
pp. 505-508
Author(s):  
Cheol Jin Kim ◽  
In Sup Ahn ◽  
Kwon Koo Cho ◽  
Sung Gap Lee ◽  
Jun Ki Chung
Keyword(s):  
Thin Films ◽  
Heat Treatment ◽  
Grain Size ◽  
Sol Gel ◽  
Surface Oxidation ◽  
Cold Isostatic Pressing ◽  
Tube Furnace ◽  
Treatment Conditions ◽  
Average Grain Size ◽  
Cold Rolling And Annealing

LiNiO2 thin films for the application of cathode of the rechargeable battery were fabricated by Li ion diffusion on the surface oxidized NiO layer. Bi-axially textured Ni-tapes with 50 ~ 80 μm thickness were fabricated using cold rolling and annealing of Ni-rod prepared by cold isostatic pressing of Ni powder. Surface oxidation of Ni-tapes were conducted using tube furnace or line-focused infrared heater at 700 °C for 150 sec in flowing oxygen atmosphere, resulted in NiO layer with thickness of 400 and 800 μm, respectively. After Li was deposited on the NiO layer by thermal evaporation, LiNiO2 was formed by Li diffusion through the NiO layer during subsequent heat treatment using IR heater with various heat treatment conditions. IR-heating resulted in the smoother surface and finer grain size of NiO and LiNiO2 layer compared to the tube-furnace heating. The average grain size of LiNiO2 layer was 0.5~1 μm, which is much smaller than that of sol-gel processed LiNiO2. The reacted LiNiO2 region showed homogeneous composition throughout the thickness and did not show any noticeable defects frequently found in the solid state reacted LiNiO2, but crack and delamination between the reacted LiNiO2 and Ni occurred as the reaction time increased above 4hrs.

Microstructural Evolution of Epitaxial LiNbO3 Thin Films Derived From Metal Alkoxide Solutions

1990 ◽  
Vol 202 ◽  
Author(s):  
Keiichi Nashimoto ◽  
Michael J. Cima ◽  
Wendell E. Rhine
Keyword(s):  
Thin Films ◽  
Grain Growth ◽  
Single Phase ◽  
Sol Gel ◽  
Precursor Solution ◽  
Epitaxial Films ◽  
Metal Alkoxide ◽  
High Annealing Temperature ◽  
Sapphire Substrates ◽  
High Annealing

ABSTRACTThe evolution of the microstructure of sol-gel derived LiNbO3 thin films was investigated to understand the growth of epitaxial films. LiNbO3 films were prepared from a precursor solution of lithium ethoxide and niobium pentaethoxide. Prehydrolysis promoted the development of polycrys-talline LiNbO3 films, whereas nonhydrolysis produced solid-state epitaxial growth of LiNbO3 films on sapphire substrates. Although the films looked smooth after annealing at 400°C, the morphology of the films changed, depending on substrates and precursors, due to grain growth at high annealing temperature. Prehydrolysis of the alkoxides caused a decrease in the temperature at which grain growth occurred, whereas the film prepared from the nonhydrolyzed precursor on a sapphire substrate showed denser texture and contained abnormally large domains that appeared to be single phase.

Fabrication and characterization of sol-gel-derived zinc oxide thin-film transistor

2010 ◽  
Vol 25 (4) ◽  
pp. 695-700 ◽  
Author(s):  
Young Hwan Hwang ◽  
Seok-Jun Seo ◽  
Byeong-Soo Bae
Keyword(s):  
Thin Film ◽  
Zinc Oxide ◽  
Low Cost ◽  
Sol Gel ◽  
Solution Process ◽  
Precursor Solution ◽  
Solution Concentration ◽  
Oxide Thin Film ◽  
Zno Films ◽  
Electron Conduction

Thin-film transistors (TFTs) with zinc oxide channel layers were fabricated through a simple and low-cost solution process. Precursor solution concentration, annealing temperature, and the process were controlled for the purpose of improving the electrical properties of ZnO TFTs and analyzed in terms of microstructural scope. The fabricated ZnO films show preferential orientation of the (002) plane, which contributes to enhanced electron conduction and a dense surface. The results show that the TFT characteristics of the film are clearly affected by the microstructure. The optimized TFT operates in a depletion mode, shows n-type semiconductor behavior, and is highly transparent (>90%) within the visible light range. It exhibits a channel mobility of 9.4 cm2/V·s, a subthreshold slope of 3.3 V/decade, and an on-to-off current ratio greater than 105. In addition, the result of N2 annealing shows the possibility of improvement in electrical property of the ZnO TFTs.

PREPARATION AND STRUCTURE CHARACTERIZATION OF BiFeO3-SrBi2Nb2O9 THIN FILMS ON SILICON BY SOL-GEL PROCESSING

2002 ◽  
Vol 16 (28n29) ◽  
pp. 4455-4459
Author(s):  
HAOSHUANG GU ◽  
WANQIANG CAO ◽  
JUNMIN XUE ◽  
JOHN WANG
Keyword(s):  
Thin Films ◽  
Sol Gel ◽  
Precursor Solution ◽  
Monomethyl Ether ◽  
Structure Characterization ◽  
Layered Perovskite ◽  
Heat Treated ◽  
Average Grain Size ◽  
Gel Processing

A new system 0.1 BiFeO 3-0.9 SrBi 2 Nb 2 O 9 thin films have been successfully prepared by an ethanolamine-modified sol-gel technique. The precursor solution was synthesized from compounds, Bi(NO 3)3· 5H 2 O , Sr(NO 3)2, Fe(NO 3)3· 9H 2 O and Nb(OC 2 H 5)5 in solution ethylene glycol monomethyl ether. The thin films were deposited on Si single crystal by spinning coating, and heat-treated at temperatures ranging from 400°C to 700°C. Crystallization of thin films occurred at about 500 ~ 600°C and the films exhibit a pure phase of layered perovskite ferroelectric structure. The grain of films is well distributed and the average grain size of the film is about 100nm.

scholarly journals Morphological and Structural Properties of Sol-Gel Derived ZnO Thin Films Spin-Coated on Different Substrates

2020 ◽  
Vol 301 ◽  
pp. 35-42
Author(s):  
Nabihah Kasim ◽  
Zainuriah Hassan ◽  
Way Foong Lim ◽  
Sabah M. Mohammad ◽  
Hock Jin Quah
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
High Resolution ◽  
Structural Properties ◽  
Low Cost ◽  
Zinc Acetate Dihydrate ◽  
Sol Gel ◽  
Precursor Solution ◽  
Xrd Analysis ◽  
Zno Thin Films

In this work, ZnO thin films were prepared by the low-cost sol-gel deposition method onto six different substrates (glass, ITO coated glass, sapphire (Al2O3), p-Si, p-GaN and polyethylene terephthalate (PET)) to study the effects of these substrates on the morphological and structural properties of the produced films. Precursor solution is Zinc acetate dihydrate based dissolved in ethanol with monoethanolamine (C2H7NO) added to act as a stabilizing agent to the sol. The corresponding ZnO thin films were characterized using field emission scanning electron microscopy (FESEM), high resolution X-ray diffraction (XRD) and atomic force microscopy (AFM). Results revealed distinct morphological and structural properties of ZnO thin films deposited on each substrate. The most uniform morphology was identified on glass, owing to the acquisition of the averagely stable grain sizes (58 nm – 61 nm) and thin film thicknesses (280 nm – 325 nm). High resolution XRD analysis showed that the films deposited on glass, ITO, p-Si, and p-GaN were attributed to hexagonal crystallite structures while the films deposited on sapphire and PET substrates exhibited amorphous phases. Amongst the samples, the ZnO thin film spin coated on p-Si demonstrated preferred orientation in (002) direction.

Size Effects and Domains in Ferroelectric Thin Film Actuators

1996 ◽  
Vol 433 ◽  
Author(s):  
S. Trolier-Mckinstry ◽  
C. A. Randall ◽  
J. P. Maria ◽  
C. Theis ◽  
D. G. Schlom ◽  
...  
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Domain Walls ◽  
Sol Gel ◽  
Ferroelectric Thin Film ◽  
Ferroelectric Thin Films ◽  
Grain Sizes ◽  
Average Grain Size ◽  
Ferroelectric Domains ◽  
Gel Processing

AbstractFerroelectric thin films typically differ from bulk ceramics in terms of both the average grain size and the degree of stress imposed on the film by the substrate. Studies on bulk ceramics have demonstrated that the number of domain variants within grains depends on the grain size for sizes <˜lμm. This can diminish the poling efficiency of the material. Since most thin films show primary grain sizes well below a micron, similar effects should be observed in films. In addition, since the perovskite ferroelectrics contain ferroelastic as well as ferroelectric domains, it seems clear that stress in thin films may markedly alter the degree to which domain walls contribute to the observed properties. In this paper, the relative importance of these factors are discussed for several types of ferroelectric thin films. Films have been prepared by pulsed laser deposition, magnetron sputtering, and by sol-gel processing. It has been found that epitaxial BaTiO3 films are ferroelectric at 77K down to thicknesses as low as ˜ 60nm. Data on the low and high field electrical properties are reported as a function of temperature, the film crystallinity, and film thickness for representative perovskite films.

Influence of Strontium Concentration on the Microstructure and Electrical Properties of Sol-Gel Derived Barium Strontium Titanate Thin Films

1996 ◽  
Vol 433 ◽  
Author(s):  
M.C. Gust ◽  
L.A. Momoda ◽  
M.L. Mecartney
Keyword(s):  
Thin Films ◽  
Dielectric Constant ◽  
Grain Size ◽  
Barium Strontium Titanate ◽  
Sol Gel ◽  
Heat Treating ◽  
Si Substrates ◽  
Barium Strontium ◽  
Average Grain Size ◽  
Alkoxide Precursors

AbstractBaxSrl−xTiO3 thin films with varying Sr concentration were prepared on Pt coated Si substrates using methoxypropoxide based alkoxide precursors. Films were crystallized by heat treating at 700°C for 30 minutes in an oxygen atmosphere after deposition of each layer. Film thickness ranged from 230 to 260 nm. No evidence of tetragonality was observed in any of the compositions. Films with higher Sr concentrations had a larger average grain size, larger grain size distribution, and increased (111) orientation on (111) oriented Pt. The highest dielectric constant of ˜400 was found for Ba 0.5Sr0.5TiO3, although no direct correlation could be made between the composition and dielectric properties.

scholarly journals Strain-Mediated Substrate Effect on the Dielectric and Ferroelectric Response of Potassium Sodium Niobate Thin Films

Coatings ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 449 ◽  
Author(s):  
Alexander Tkach ◽  
André Santos ◽  
Sebastian Zlotnik ◽  
Ricardo Serrazina ◽  
Olena Okhay ◽  
...  
Keyword(s):  
Thin Films ◽  
Parallel Plate ◽  
Strain State ◽  
Low Cost ◽  
Sol Gel ◽  
Sodium Niobate ◽  
Thermal Expansion Mismatch ◽  
Potassium Sodium Niobate ◽  
Parallel Plate Capacitor ◽  
Piezoelectric Thin Films

If piezoelectric thin films sensors based on K0.5Na0.5NbO3 (KNN) are to achieve commercialization, it is critical to optimize the film performance using low-cost scalable processing and substrates. Here, sol–gel derived KNN thin films are deposited using a solution with 5% of potassium excess on Pt/TiO2/SiO2/Si and Pt/SrTiO3 substrates, and rapid thermal annealed at 750 °C for 5 min. Despite an identical film morphology and thickness of ~335 nm, an in-plane stress/strain state is found to be tensile for KNN films on Pt/TiO2/SiO2/Si, and compressive for those on Pt/SrTiO3 substrates, being related to thermal expansion mismatch between the substrate and the film. Correspondingly, KNN films under in-plane compressive stress possess superior dielectric permittivity and polarization in the parallel-plate-capacitor geometry.

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