A Thickness Dependent Study of SrBi2Nb2O9 Thin Films

1997 ◽  
Vol 493 ◽  
Author(s):  
W. Pérez ◽  
E. Ching-Prado ◽  
A. Reynés-Figueroa ◽  
R. S. Katiyar ◽  
D. Ravichandran ◽  
...  
Keyword(s):  
Thin Films ◽  
Raman Spectra ◽  
Raman Band ◽  
Sol Gel ◽  
Orthorhombic Symmetry ◽  
Silicon Substrates ◽  
X Ray Diffraction ◽  
Coexistence Of Phases ◽  
Raman Study ◽  
Si Films

ABSTRACTThin films of SrBi2Nb2O9 (SBN) with thickness of 0.1, 0.2, 0.3 and 0.4 μm were grown by sol-gel technique on platinum/silicon substrates, and annealed at 800°C. Raman spectra of the samples present bands around 170,210, 272, 300,430, 580, 717, and 839 cm−1 which correspond to the SBN formation. The prominent Raman band around 839 cm−1, which is the Alg mode of the orthorhombic symmetry, is assigned to the symmetric stretching of the NbO6 octahedrals. The frequency of this band is found to shift at different places in the same sample, as well as from sample to sample. The frequency and width variations of the Raman bands are discussed in term of ions in non-equilibrium positions, which seem to be related with the crystallization degree in the SBN samples. Also, the Raman study indicates the presence of foreign sharp peaks, which are associated with the coexistence of phases other than SBN. The thickness dependence of the Raman spectra and the X-ray diffraction are also discussed. Finally, the experimental results of the SBN/Pt/Si films grown at 800°C are compared with those obtained at 650°C.

Characterization of SrBi2Nb2O9 Thin Films Prepared by Sol Gel Technique

1996 ◽  
Vol 459 ◽  
Author(s):  
E. Ching-Prado ◽  
W. Pérez ◽  
A. Reynés-Figueroa ◽  
R. S. Katiyar ◽  
D. Ravichandran ◽  
...  
Keyword(s):  
Thin Films ◽  
Raman Band ◽  
Sol Gel ◽  
Orthorhombic Symmetry ◽  
X Ray Diffraction ◽  
Ft Ir ◽  
Gel Technique ◽  
High Degree ◽  
First Time

ABSTRACTThin films of SrBi2Nb2O9 (SBN) with thicknesses of 0.1, 0.2, and 0.4 μ were grown by Sol-gel technique on silicon, and annealed at 650°C. The SBN films were investigated by Raman scatering for the first time. Raman spectra in some of the samples present bands around 60, 167, 196, 222, 302, 451, 560, 771, 837, and 863 cm−1, which correspond to the SBN formation. The study indicates that the films are inhomogeneous, and only in samples with thicknesses 0.4 μ the SBN material was found in some places. The prominent Raman band around 870 cm−1, which is the A1g mode of the orthorhombic symmetry, is assigned to the symmetric stretching of the NbO6 octahedrals. The frequency of this band is found to shift in different places in the same sample, as well as from sample to sample. The frequency shifts and the width of the Raman bands are discussed in term of ions in non-equilibrium positions. FT-IR spectra reveal a sharp peak at 1260 cm−1, and two broad bands around 995 and 772 cm−1. The bandwidths of the latter two bands are believed to be associated with the presence of a high degree of defects in the films. The experimental results of the SBN films are compared with those obtained in SBT (T=Ta) films. X-ray diffraction and SEM techniques are also used for the structural characterization.

Characterization of Sol-Gel Derived (Pb,Ba)(Zr,Ti,Nb)O3 Thin Films for Optical Waveguide Development

1994 ◽  
Vol 343 ◽  
Author(s):  
P. F. Baude ◽  
J. S. Wright ◽  
C. Ye ◽  
L. F. Francis ◽  
D. L. Polla
Keyword(s):  
Thin Films ◽  
Sol Gel ◽  
Silicon Substrates ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sapphire Substrates ◽  
Solution Preparation ◽  
Transmission Measurements ◽  
Gel Technique

ABSTRACT(PbBa)(ZrTiNb)03 thin films and powders have been prepared using the sol-gel technique. Solutions were synthesized in 2-methoxyethanol based upon our previous PZT solution preparation. Three different approaches were used for incorporating barium into PZT alkoxide solutions. Thermal analysis and x-ray diffraction results indicated that barium methoxypropoxide gave the best results. PBZTN (71% Pb and 71% Zr) was deposited onto sapphire substrates as well as oxidized silicon substrates. Optical transmission measurements showed greater than 80% transmission for wavelengths longer than 400 nm. Films with thickness of 3000 Å on sapphire exhibited a refractive index of 2.19 at λ=633 nm.

Micro-Raman Study of Sol-Gel Grown Pmn-PT Thin Films

1995 ◽  
Vol 392 ◽  
Author(s):  
E. Ching-Prado ◽  
R. W. Tao ◽  
A. R. Guo ◽  
R. S. Katiyar ◽  
A. S. Bhalla
Keyword(s):  
Thin Films ◽  
Raman Spectra ◽  
Sol Gel ◽  
Relaxation Times ◽  
Weighted Average ◽  
Momentum Conservation ◽  
Temperature Dependent ◽  
Raman Study ◽  
Xrd Techniques ◽  
Pt Films

AbstractThin films of 0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 (PMN-PT) were prepared by sol-gel technique and deposited on platinum coated-silicon wafer. The thicknesses of the two films were ∼400 nm and ∼550 nm, respectively. Micro-Raman spectra of the PMN-PT films show strong broad bands centered at 50, 136, 276, 450, 510, 556, and 790 cm−1, which are characteristic of PMN formation. Temperature dependent Raman scattering from 290K to 70K did not show any significant change in the bandwidth of the peaks, meaning thereby that the relaxation times of these phonons are practically temperature independent. The bands are interpreted as due to a break down in the phonon momentum conservation within the Brillouin zone, which is associated with some degree of disorder in the material. As a result, the Raman spectrum is a weighted average of the density of phonon states. Micro-Raman measurements in many different places on the films clearly indicate that they are homogeneous. In addition, the differences found in the Raman spectra of the films, particularly the band at 790 cm−1 is discussed. FT-1R measurements of the PMN-PT films present two broad bands around 260 and 550 cm−1, which are characteristic of perovskite structure and are primarily due to motions of oxygen ions. Also, these bands are compared with those found in PMN single crystal, and with those found in other similar systems, such as PLZT and PSN. SEM and XRD techniques have been used for the structural characterization.

Photoluminescence of Nanocrystalline Bismuth Titanate Thin Films Synthesized by the Sol-Gel Method

2006 ◽  
Vol 514-516 ◽  
pp. 128-132 ◽  
Author(s):  
Agata Lisińska-Czekaj ◽  
M. Czaja ◽  
Lucjan Kozielski ◽  
Dionizy Czekaj ◽  
M. Piechowiak ◽  
...  
Keyword(s):  
Thin Films ◽  
Bismuth Titanate ◽  
Sol Gel ◽  
Diffraction Method ◽  
Orthorhombic Symmetry ◽  
X Ray Diffraction ◽  
Sol Gel Process ◽  
Uv Luminescence ◽  
Perovskite Type ◽  
Perovskite Type Structure

The present study is devoted to synthesis and investigation of photoluminescence in the nanosized Bi4Ti3O12 (BTO) thin films. The randomly oriented BTO thin films have been obtained by a modified hybrid sol-gel process. Bismuth nitrate and titanium (IV) butoxide were used as the starting materials. The thin films were deposited on silicon, glass and stainless steel by spin coating and crystallized by the conventional thermal annealing at temperature T=650°C. Formation of the layer perovskite-type structure of the orthorhombic symmetry was confirmed by X-ray diffraction method. Conservation of the chemical composition was investigated by energy dispersive spectroscopy. The UV luminescence has been observed in BTO thin films at room temperature. Results on luminescence excitation and emission in bismuth titanate thin films are given in the present paper.

scholarly journals Surface and Optical Properties of Gd-Doped ZrO2 Nano Films

2020 ◽  
Vol 4 (1) ◽  
pp. 4
Author(s):  
Ognian Dimitrov ◽  
Irina Stambolova ◽  
Sasho Vassilev ◽  
Katerina Lazarova ◽  
Silvia Simeonova
Keyword(s):  
Thin Films ◽  
Rare Earth ◽  
Sol Gel ◽  
Earth Metal ◽  
Silicon Substrates ◽  
X Ray Diffraction ◽  
Average Roughness ◽  
Force Microscopy ◽  
Atomic Force ◽  
Skin Conditions

Nanosized coatings of ZrO2 were deposited on silicon substrates using sol-gel and spin coating techniques. The precursor solutions were prepared from ZrOCl2.8H2O with the addition of different percentage (0.5–5%) of rare earth Gd3+ ions as dopant. The thin films were homogeneous, with average thickness of 115 nm and refractive index (n) of 1.83. The X-ray diffraction analysis (XRD) revealed the presence of a varying mixture of monoclinic and tetragonal ZrO2 polycrystalline phases, depending on the dopant, all of which with nanosized crystallites. Scanning electron microscopy (SEM) as well as atomic force microscopy (AFM) methods were deployed to investigate the surface morphology and roughness of the thin films, respectively. They revealed a smooth, well uniform and crack-free surface with average roughness of 0.8 nm. It was established that the dopant concentration affects the photoluminescence (PL) properties of the samples. The undoped films exhibited broad violet-blue PL emission, while the addition of Gd3+ ions resulted in new narrow bands in both UV-B and visible light regions, characteristic of the rare earth metal. The intensive emission located at 313 nm can find useful application in medical lamps for treatment of different skin conditions.

Chemical Synthesis, Characterization and Gas-Sensing Properties of Thin Films in the In2O3-SnO2 System

2004 ◽  
Vol 828 ◽  
Author(s):  
Mauro Epifani ◽  
Raül Díaz ◽  
Antonella Taurino ◽  
Luca Francioso ◽  
Pietro Siciliano ◽  
...  
Keyword(s):  
Thin Films ◽  
Gas Sensing ◽  
Sol Gel ◽  
Nominal Composition ◽  
Silicon Substrates ◽  
X Ray Diffraction ◽  
Resistance Change ◽  
Solution Processes ◽  
Starting Solutions ◽  
Better Than

ABSTRACTThin films in the SnO2-In2O3 system, with relative concentrations of the two oxides ranging from 2% to 98% (molar percentage of the oxide), were deposited by sol-gel and solution processes. The films for the physical characterizations were deposited onto oxidized silicon substrates, while the films for the gas-sensing tests were deposited onto alumina. The starting solutions were characterized by FTIR spectroscopy, while the films on silicon, heated at various temperatures, were characterized by X-ray diffraction and SEM observations. The interaction between the two systems is particularly evident in the case of the system described by a 50% In2O3-50% SnO2 nominal composition. The crystallization on In2O3 during the film heat-treatment hinders the crystallization of SnO2, thus Sn is dispersed as an n-dopant in the In2O3 lattice, indeed showing a current signal, in the gas-sensing test, two orders of magnitude higher than the pure film. The response of the mixed-oxide based device to NO2 is better than pure In2O3. On the other hand, the response (relative resistance change) of pure SnO2 to low (from 0.1 to 1 ppm) NO2 concentrations ranges from 150 to 300, a result that can be correlated with the nanostructure of the film, which, from SEM and XRD results, seems constituted by very small grains.

Raman study of oriented ZnO thin films deposited by sol–gel method

2008 ◽  
Vol 71 (4) ◽  
pp. 1234-1238 ◽  
Author(s):  
S. Ben Yahia ◽  
L. Znaidi ◽  
A. Kanaev ◽  
J.P. Petitet
Keyword(s):  
Thin Films ◽  
Sol Gel ◽  
Zno Thin Films ◽  
Gel Method ◽  
Sol Gel Method ◽  
Raman Study

Microwave Absorbing Ferrite Thin Films for Microwave Heating of Microstructured Reactors

2009 ◽  
Vol 1222 ◽  
Author(s):  
Pengzhao Gao ◽  
Evgeny V. Rebrov ◽  
Jaap C. Schouten ◽  
Richard Kleismit ◽  
John Cetnar ◽  
...  
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Microwave Heating ◽  
Near Field ◽  
Coplanar Waveguide ◽  
Sol Gel ◽  
Microwave Cavity ◽  
Silicon Substrates ◽  
Microwave Microscopy ◽  
Zn Ferrite

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.

ITO Thin Films on Silicon Buffer by Sol Gel Method

2006 ◽  
Vol 514-516 ◽  
pp. 1155-1160 ◽  
Author(s):  
Talaat Moussa Hammad
Keyword(s):  
Thin Films ◽  
Indium Tin Oxide ◽  
Optical Transmission ◽  
Sol Gel ◽  
Precursor Solution ◽  
Charge Carriers ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ito Thin Films ◽  
Uv Visible

Sol gel indium tin oxide thin films (In: Sn = 90:10) were prepared by the sol-gel dipcoating process on silicon buffer substrate. The precursor solution was prepared by mixing SnCl2.2H2O and InCl3 dissolved in ethanol and acetic acid. The crystalline structure and grain orientation of ITO films were determined by X-ray diffraction. The surface morphology of the films was characterized by scanning electron microscope (SEM). Optical transmission and reflectance spectra of the films were analyzed by using a UV-visible spectrophotometer. The transport properties of majority charge carriers for these films were studied by Hall measurement. ITO thin film with electrical resistivity of 7.6 ×10-3 3.cm, Hall mobility of approximately 2 cm2(Vs)-1 and free carrier concentration of approximately 4.2 ×1020 cm-3 are obtained for films 100 nm thick films. The I-V curve measurement showed typical I-V characteristic behavior of sol gel ITO thin films.

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.

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