We prepare optrodes of fiber optic plastic with sol-gel technique. Suitable concentration of carbone nanotubes (CNTs),
phenol red, bromophenol blue and cresol red, design optrodes with fiber optic plastic. The surface charge of silica and
the refractive index, which play an important roll on the fiber, modifies the conditions of light propagation into the
plastic optical fiber. We use the transmittance to measure the pH of a solution or fluid in a range between 3 and 9.
Design and characterization of a pH optical fiber sensor with a pH sensitive dye is described in this paper. TEOS (Tetra-ethyl-Orto-Silicate) was used to dope a plastic optical fiber, which will be used as the probe. The sensor is prepared by fixing the doped plastic fiber on a fused ortosilica block surface with blue bromophenol. The fiber surface charged with silica and the refractive index, which plays an important roll on the fiber, modifies the conditions of light propagation into the plastic optical fiber. The fiber transmittance is used to measure the pH of a solution or a fluid in a range between 7 and 10.5. Such signal is captured by a photodetector and processed with a LabView development environment which also controls a hardware designed in our laboratory. The advantage of this system is that 2cm of doped fiber are enough to measure the pH of a fluid in real time. The response time of this system is approximately 10s.
Barium titanate sol was prepared using barium 2-ethyl-hexanoate and titanium isopropoxide. The sol was then spin coated on Si (100) and MgO (100) substrates and annealed at different temperatures to give polycrystalline, transparent, and crack free films. The surface morphology and structural properties of the film were studied using X-ray diffraction (XRD), Rutherford Backscattering Spectroscopy (RBS) and, Scanning Electron Microscopy (SEM).
Typical characteristics of BaTiO3 thin films, such as hysterisis behavior, spontaneous polarization below the Curie temperature, faster switching speed etc., are particularly of much attention for high capacitance integrated elements, dynamic random access memories (DRAMs), phase conjugation, holographic optical data storage, two-beam coupling and optical computing. Several techniques have been employed for the fabrication process of such ferroelectric thin films. Among other methods, Sol-Gel and MOD prove to be a powerful and inexpensive means to deposit thin films. The main advantages of these deposition techniques are good homogeneity, ability to precisely control the stoichiometry of the film, lower temperature processing, and the ability to produce high-purity materials for electronics and optics without much investment in equipment. We report the structural characterization of BaTiO3 films deposited on single crystal Si (100) and MgO (100) substrates by sol-gel process. The films were prepared by the sol-gel process and annealed at different temperatures. In this method the sol-gel polymerization is initiated by adding water to a solution of alkoxide in methanol. The chemical conditions are generally chosen in such a way that nearly complete hydrolysis occurs. A series of experiments ranging from X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), were conducted on the spin-coated films and their correspondingly annealed films at different temperatures.
We report the synthesis of polycrystalline barium titanate BaTiO3 thin films on silicon substrate prepared by sol- gel technique. The structure and composition of ferroelectric film ms have been analyzed by using x-ray photoelectron spectroscopy and Rutherford backscattering spectroscopy. These methods provide information on the core level electronic states and the film composition. The results indicate the films have no distinctive deviation from the stoichiometry within the accuracy of both spectroscopic methods. Thus, this study of surface structure and composition of ferroelectric films could lead to a better understanding of the observed change of electrical and optical properties and to the design of improved devices such as dynamic random access memories.
The characteristics of thin BaTiO3 films deposited on Si and MgO substrates by employing the metal-organic deposition
technique are studied. In the experiment, the commercial barium 2-ethyihexanoate and the synthesized titanium dimethoxy
dineodecanoate are used as precursors for the formation of BaTiO3 films. The film characterization is performed by X-ray
diffraction and the scanning electron microscopy. The obtained results show that the prepared films have nearly good
stoichiometry and the obtained tetragonal structure properties of BaTiO3 indicates that these may fmd some possible
optical/electrical applications in the field ofintegrated optics technology.