Influence of chemical reduction on optical and electrical properties of LiTaO3 crystal (original) (raw)
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Optical Properties of LiTaO3 Thin films crystallized by RTA processes
Journal of Electroceramics, 2006
High-performance pyroelectric infrared detectors have been fabricated using Lithium tantalite (LiTaO 3) thin films deposited on Pt(111)/Ti/SiO 2 /Si(100) substrates by diol-based sol-gel method and rapid thermal annealing (RTA) technique. The dielectric and pyroelectric properties of IR detectors of LiTaO 3 thin films crystallized by conventional and RTA processes are investigated. Experimental results reveal that the heating rate will influence strongly on dielectricity and pyroelectricity of LiTaO 3 thin films. The voltage responsivities (Rv) measured at 80 Hz increase from 5496 to 8455 V/W and the specific detecivities (D *) measured at 300 Hz increase from 1.94 × 10 8 to 2.38 × 10 8 cmHz 1/2 /W with an increase of heating rate from 600 to 1800 • C/min. However, the voltage responsivity and the specific detecivity decrease with heating rate in excess of 1800 • C/min. The results show that the LiTaO 3 thin film detector with a heating rate of 1800 • C/min exists both the maximums of voltage responsivity and specific detecivity.
Characterization of Optical and Structural of Lanthanum Doped LiTaO3Thin Films
Integrated Ferroelectrics, 2015
Undoped, 5%, and 10% lanthanum doped lithium tantalate thin films were annealed at 550 • C temperature for 12.5 hours and their properties were characterized. The results showed that the dopant addition affects the crystal formation of LiTaO 3 , especially the 10% La 2 O 5 dopant, where the lattice of a = 5.11 Å, c = 13.30 Å, and its crystal was hexagonal. The observed functional groups were O-H, N-H, C = C, Li-O, Ta-O. The higher La 2 O 5 dopant concentration leads to the higher absorption of Ta-O and Li-O, the lower the energy gap, the higher the refractive index, and the smaller the particle size of thin films.
Deposition of LiTaO3 thin films by pyrosol process
Thin Solid Films, 1997
Lithium tantalate (LiTaO 3) thin films with submicron thickness were prepared by the "pyrosol" process based on the thermal decomposition on a heated substrate of an aerosol obtained by ultrasonic spraying. The crystalline orientations of the films versus different experimental parameters, like the substrate nature and the deposition temperature, were studied. Crystalline structure analysis of deposited materials showed that LiTaO 3 films crystallized successfully with single orientation on c-oriented sapphire substrates, without using post-thermal annealing treatment.
Microelectronics Journal, 2008
In this paper, we report the first results obtained for pyroelectric LiTaO 3 thin films prepared on silicon substrates by electrostatic spray pyrolysis (ESP), a simple, low cost and efficient technique not widely used for LiTaO 3 deposition, using lithium acetylacetonate and tantalum ethoxide in a mixture of methanol. The effect of the growth and annealing temperature on the structural and optical properties has been investigated. X-ray diffraction measurements have shown that LiTaO 3 thin films became preferentially oriented in the (0,1,2) plane after annealing treatment in an oxygen environment using the rapid thermal processing. On the other hand, a thermal stress's modeling is performed to observe the effect of growth temperature on the as-deposited films and the substrates. The SEM images have shown that the film heat-treated at 600 1C became more homogeneous and smoother than that before annealing. The optical phonon modes of the LiTaO 3 thin films have been also investigated using infrared reflectivity (FTIR) and Raman spectroscopy. r
2017
This experiment aims to investigate the electrical conductivity and the resonance frequency of thin films. The materials of thin film made from 7059 corning glass substrate, lithium acetate, tantalum pentoxide, gallium oxide and also using 2-methoxyethanol as solvent. The growth of thin film is done by using the tool of spin coater at 7059 corning glass substrate with dimension 11 cm2 and annealed in furnace for eight hours with a temperature of 550 oC. Thin films also have been prepared by Metal Organic Chemical Vapor Deposition (MOCVD) technique to create the aluminum contacts at 7059 corning glass substrate and the thin film layer with dimension 22 mm2. The thin film is measured by using LCR meter to found the data of conductance and phase in range frequency at 50Hz 5MHz. The results of electrical conductivity curve shows in range 10-8 10-6 and LiTaO3 with doping (10%) Ga2O3 shows increasing the number of resonance frequency. Based on these results, it can be concluded that the...
Self-Polarized Pyroelectric LiTaO3 thin films
We present a characterization study to develop selfpolarized, highly pyroelectric lithium tantalate thin films obtained by RF magnetron sputtering. A preliminary work is done on the bottom electrode to reduce short-term variations of the pyroelectric behavior. Then, the influence of pressure and of deposition temperature is studied to determine the best set of parameters as to obtain a large pyroelectric behavior. The crystalline structure modification as well as the influence on the pyroelectric coefficient have been studied in each case. An asdeposited pyroelectric coefficient as high as 32 µC.m -2 .K -1 has been obtained for the optimal set of pressure (2 mTorr) and temperature (630 °C).
2017
This study aims to investigatedielectric constant and impedance characteristic of thin films made from LiTaO3 without (0%) and with doping (10%) Ga2O3. The solubility of LiTaO3 for the purpose of this study is regulated at 1 M by using 2-methoxyethanol [(CH3OCH2CH2OH)] as solvent. The growth of thin films on 7059 corning glass substrate was processed by Chemical Solution Deposition (CSD) method. By using a spin coater device on a speed of 3000 rpm for 30 seconds, the substrate is then annealed in furnace at a temperature of 550 C for eight hours. To create aluminum contacts, the thin films were then further processed by involving Metal Organic Chemical Vapor Deposition (MOCVD) technique. The final thin films weremeasured by LCR meter to provide certain data such as: inductance, capacitance and resistance values in range frequency from 50 Hz to 5 MHz. The study concludes that the film thickness (made from LiTaO3 without (0%) and with doping (10%) Ga2O3) as separator material between ...
Characterization of Optical and Structural of Lanthanum Doped LiTaO3Thin Films
Integrated Ferroelectrics, 2015
Undoped, 5%, and 10% lanthanum doped lithium tantalate thin films were annealed at 550 • C temperature for 12.5 hours and their properties were characterized. The results showed that the dopant addition affects the crystal formation of LiTaO 3 , especially the 10% La 2 O 5 dopant, where the lattice of a = 5.11 Å, c = 13.30 Å, and its crystal was hexagonal. The observed functional groups were O-H, N-H, C = C, Li-O, Ta-O. The higher La 2 O 5 dopant concentration leads to the higher absorption of Ta-O and Li-O, the lower the energy gap, the higher the refractive index, and the smaller the particle size of thin films.
Dielectric and pyroelectric properties of LiTaO3:P(VDF-TrFE) composite films
2009
Pyroelectric infrared radiation detectors are one of kind thermal sensors, operating at ambient temperature, unlike semiconductor detectors, which require cooling. They also have a uniform spectral response in a wide range of wavelengths, including the main band of infrared transmission of the earth's atmosphere. Recently, 0-3 composites consisting of ferroelectric ceramic particles dispersed in a ferroelectric polymer have stimulated interest due to their good mechanical flexibility and strength, and excellent piezoelectric and pyroelectric properties. Lithium tantalite [(LiTaO3), LT] ceramic particles have been incorporated into a polyvinylidene fluoride-trifluoroethylene [P(VDF-TrFE) 70/30 mol%] copolymer matrix to form composite films. The films were prepared using solvent casting method with the LT powder homogeneously dispersed in the P(VDF-TrFE) copolymer matrix with various volume fractions. Electrical properties such as the dielectric constant, dielectric loss, and pyr...