Effect of heat treatment on formation of sol-gel (Pb, La)TiO3 films for optical application

1997 ◽  
Vol 12 (3) ◽  
pp. 812-818 ◽  
Author(s):  
Junmo Koo ◽  
Sung-Uk Kim ◽  
Dae Sung Yoon ◽  
Kwangsoo No ◽  
Byeong-Soo Bae
Keyword(s):  
Heat Treatment ◽  
Refractive Index ◽  
Film Thickness ◽  
Optical Transmission ◽  
Thick Films ◽  
Sol Gel ◽  
Propagation Loss ◽  
Optical Propagation ◽  
Lanthanum Titanate ◽  
Sol Gel Films

Lead lanthanum titanate [(Pb, La)TiO3] sol-gel films have been prepared to investigate the effect of heat treatment on the fabrication of uniform and crack-free thick films by applying different heating schedules. The surface morphology as well as the optical properties such as refractive index, optical transmission, and optical propagation loss of the films was examined, depending on the film thickness. Because the slower and longer heating is enough to remove the organic and nitrate residues and diminish the thermal shock while heating the films, slower and longer heating can produce the uniform and crack-free thick films having higher refractive index as well as lower optical propagation loss. Also, the drying and heating of the films on a hot plate in every coating resulted in the fabrication of thick films having above 8000 Å without any defects and microcracks. This film presented the highest refractive index as well as the lowest optical propagation loss which grows exponentially with increasing the film thickness due to the scattering of defects in the film.

Sol-Gel Derived Polyvinylpyrrolidone/Silicon Oxide Composite Materials and Novel Fabrication Technique for Channel Waveguide

1995 ◽  
Vol 392 ◽  
Author(s):  
Makoto Yoshida ◽  
Paras N. Prasad
Keyword(s):  
Thermal Decomposition ◽  
Refractive Index ◽  
Composite Materials ◽  
Silicon Oxide ◽  
Sol Gel ◽  
Propagation Loss ◽  
Slab Waveguides ◽  
Optical Propagation ◽  
Laser Densification ◽  
Channel Waveguides

AbstractSol-gel derived composite materials of polyvinylpyrrolidone (PVP), SiO2 and TiO2 were studied to achieve low optical propagation loss and high thermal stability in slab waveguides. PVP is a thermally crosslinkable polymer. However, the thermal crosslinking and thermal decomposition take place around the same temperature, 200 °C, resulting in high optical propagation loss. The incorporation of sol-gel processed SiO2 prevents thermal decomposition of PVP and produces remarkably low optical propagation loss even after being baked at 230 °C. We have achieved 0.2 dB/cm optical propagation loss at 633 nm. Furthermore, little index change was observed at 110 °C for 1,000 hours after initial slight increase. Impregnation of sol-gel processed TiO2 into the PVP/SiO2 system was also studied to increase refractive index. A broad manipulation of refractive index, from 1.49 to 1.65, with an optical propagation loss of less than 0.6 dB/cm at 633 nm was accomplished by a careful selection of Ti alkoxide and optimized reaction conditions. PVP/SiO2 slab waveguides were then used to fabricate channel waveguides by using a laser densification technique utilizing metal lines as light absorbent and an Ar laser. An optical propagation loss of 0.9 dB/cm was achieved at 633 nm.

Characterization and optical propagation loss of sol-gel derived TiO2/SiO2films

2000 ◽  
Vol 33 (23) ◽  
pp. 3013-3017 ◽  
Author(s):  
Zhai Jiwei ◽  
Yao Xi ◽  
Zhang Liangying
Keyword(s):  
Sol Gel ◽  
Propagation Loss ◽  
Optical Propagation

Ellipsometric Imaging of Drying Sol-Gel Films

1988 ◽  
Vol 121 ◽  
Author(s):  
Alan J. Hurd ◽  
C. Jeffrey Brinker
Keyword(s):  
Refractive Index ◽  
Sol Gel ◽  
Dip Coating ◽  
Drying Process ◽  
Imaging Ellipsometry ◽  
Withdrawal Velocity ◽  
Coated Film ◽  
Sol Gel Films ◽  
Physical And Chemical ◽  
Dip Coated Films

ABSTRACTAlthough controlled dip-coating is an established way to apply high quality uniform coatings, the details of the coating and drying process have not been deeply studied. Depending on the physical and chemical state of the sol and the parameters of dipping (dipping angle and speed), a variety of thicknesses and porosities can be achieved [1]. For optical coatings, the refractive index and optical thickness can thereby be controlled.We have developed a method to view the drying front of a dip-coated film using broad beam ellipsometry [2], or “ellipsometric imaging.” In dip-coated films we take full advantage of the fact that a steady state is quickly reached where the drying line velocity matches the withdrawal velocity; however, the technique might also be used in unsteady situations such as spin coating. Imaging ellipsometry makes it possible to measure the refractive index and thickness profiles of both wet and dry films point-by-point in an entire image at once. These profiles provide important clues as to the relative importance of gravity, evaporation and other phenomena.

Epitaxial Growth And Optical Properties of Sol-Gel (Pb,La)Ti03 Thin Films for Waveguides

1997 ◽  
Vol 474 ◽  
Author(s):  
Junmo Koo ◽  
Changho Lee ◽  
Kwangsoo No ◽  
Byeong-Soo Bae
Keyword(s):  
Thin Films ◽  
Surface Roughness ◽  
Refractive Index ◽  
Laser Light ◽  
Sol Gel ◽  
Surface Scattering ◽  
Sapphire Substrates ◽  
Lanthanum Titanate ◽  
Propagation Losses ◽  
Low Refractive Index

ABSTRACTLead lanthanum titanate thin films have been prepared on MgO and sapphire substrates by sol-gel method. XRD analyses confirm that the PLT films fabricated on MgO(lOO) and c-plane sapphire substrates grow preferentially with (100) and (111) orientations, respectively. The PLT films with a high La content have a low refractive index due to the decrease of the refractive index anisotropy. The propagation losses in PLT films measured, using He-Ne laser light and the prism coupling method decrease as the La content increases. This is due to the reduction of the refractive index anisotropy and the surface scattering by the surface roughness as a function of La content in the film.

Modification of Sol-Gel Thin Films By Ion Implantation

1994 ◽  
Vol 346 ◽  
Author(s):  
Hiroshi Hirashima ◽  
Kenji Adachi ◽  
Hiroaki Imai
Keyword(s):  
Thin Films ◽  
Refractive Index ◽  
Ion Implantation ◽  
Sol Gel ◽  
The Other ◽  
Ir Absorption ◽  
Absorption Bands ◽  
Chemically Modified ◽  
Sol Gel Films ◽  
Ion Species

ABSTRACTIn order to densify and to improve the physical properties, TiO2 sol-gel films, about 100 nm in thickness, on silica glass or silicon wafer were implanted with Ar+ or B+ ions. The refractive index of the as-dried films increased and the IR absorption band of OH disappeared after Ar+ implantation. Drying and densification of sol-gel films were enhanced by Ar+ implantation. On the other hand, the refractive index and the thickness of the films hardly changed with B+ implantation. However, IR absorption bands of B-O bond were observed after B+ implantation. This suggests that sol-gel films could be chemically modified by ion implantation with reactive ion species.

Refractive Index Controlled Plasmon Tuning of Au Nanoparticles in SiO2-ZrO2 Film Matrices

2008 ◽  
Vol 8 (8) ◽  
pp. 3868-3876
Author(s):  
Sucheta De ◽  
Samar Kumar Medda ◽  
Goutam De
Keyword(s):  
Heat Treatment ◽  
Refractive Index ◽  
Au Nanoparticles ◽  
Sol Gel ◽  
Dip Coating ◽  
Uv Treatment ◽  
Final Heat ◽  
Molar Ratios ◽  
Glass Substrates ◽  
Heat Treated

Au-plasmon tuning has been accomplished by controlling the refractive index (n) of the embedding film matrix. The refractive index of the film matrices were controlled by changing the molar ratios of low (SiO2) and high index (ZrO2) components following sol–gel reactions. Thus, Au nanoparticles doped films were prepared from SiO2-ZrO2 inorganic–organic hybrid sols of variable molar ratios containing HAuCl4 following the dip-coating method. The film samples deposited on glass substrates were obtained after drying, UV-treatment, and subsequent heat-treatment at 500 °C in air. The nominal mol ratios of SiO2:ZrO2 were 1:0, 1:1, 1:2.3, and 1:4. 3 equivalent mol% Au–97% total oxide (SiO2 + ZrO2) was maintained in the final heat-treated films. FTIR studies confirmed good homogeneity of Si-Zr network in the Zr-containing films. The UV-treatment has been introduced to facilitate the decomposition of HAuCl4 in the hybrid matrix prior to the heat-treatment step. The main Au-plasmon peak, in the case of a SiO2 host (SiO2:ZrO2 = 1:0, n = 1.410), observed at about 546 nm, gradually red-shifted to 592 nm upon increasing the ZrO2 content (SiO2:ZrO2 = 1:4, n = 1.847). Transmission electron microscopy of the final heat-treated (500 °C) films showed existence of plate-like (triangular and hexagonal) Au nanoparticles (25–50 nm) along with relatively smaller nanoparticles of about 10 nm in size. X-ray diffraction patterns reveal that the Au nanoparticles have a (111) orientation.

Phase transformations in TiO2/SiO2 sol-gel films as a function of composition and heat-treatment

1991 ◽  
Vol 26 (13) ◽  
pp. 3585-3592 ◽  
Author(s):  
S. M. Melpolder ◽  
A. W. West ◽  
C. L. Barnes ◽  
T. N. Blanton
Keyword(s):  
Heat Treatment ◽  
Phase Transformations ◽  
Sol Gel ◽  
Sol Gel Films

Optical Properties of Sol-Gel (Pb,La)TiO3 Thin Films For Waveguide Application

1995 ◽  
Vol 392 ◽  
Author(s):  
Byeong-Soo Bae ◽  
Won-Jong Lee ◽  
Kwang-Soo No ◽  
Dae-Sung Yoon ◽  
Sung-Uk Kim
Keyword(s):  
Thin Films ◽  
Refractive Index ◽  
Optical Properties ◽  
Crystalline Phase ◽  
Sol Gel ◽  
Lanthanum Nitrate ◽  
Processing Conditions ◽  
Heating Condition ◽  
Glass Substrates ◽  
Lanthanum Titanate

AbstractLead lanthanum titanate ((Pb1−x/100Lax)Ti1−x/400O3, x=10, 20, 28) sol-gel thin films were prepared on SiO2/Si and glass substrates using lanthanum nitrate as a La precursor. The effect of the processing conditions was investigated and the optical properties of the films were measured to obtain good films for waveguide applications. The perovskite crystalline phase is achieved regardless of the heating condition but the slower heating creates better quality films. La content in the film does not effect on the refractive index and transparency of the film.

Electrooptic properties of highly oriented Pb(Zr,Ti)O3 film grown on glass substrate using lanthanum nitrate as a buffer layer

2004 ◽  
Vol 19 (11) ◽  
pp. 3152-3156 ◽  
Author(s):  
Jong-Jin Choi ◽  
Gun-Tae Park ◽  
Hyoun-Ee Kim
Keyword(s):  
Single Crystal ◽  
Buffer Layer ◽  
Sol Gel ◽  
Metal Electrode ◽  
Lanthanum Nitrate ◽  
Propagation Loss ◽  
Optical Propagation ◽  
Amorphous Substrate ◽  
Pzt Films ◽  
Amorphous Substrates

Materials with preferred orientation exhibit unique properties that are frequently improved in comparison with those that are randomly oriented. Optical waveguide devices require high-quality single-crystal–like thin films because of their low optical propagation loss and their near–single-crystal properties. The growth mechanisms of textured films on non-lattice matched amorphous substrates, such as glass, are different from those on single-crystal substrates or the surface of a metal electrode. In this study, highly (100) oriented Pb(Zr,Ti)O3 PZT films were grown on an amorphous substrate by means of the sol-gel multicoating method, using lanthanum nitrate as a buffer layer. The lanthanum nitrate buffer layer was also very effective as a diffusion barrier against Pb-Si interdiffusion. The electrooptic properties of the PZT films were markedly enhanced when their orientation was adjusted to the (100) direction.

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