Liquid phase epitaxy of lattice-matched KTa1−xNbxO3 grown on KTaO3 substrate

Gutmann, R.; Hulliger, Jürg; Reusser, Éric

doi:10.1016/0022-0248(93)90807-9

Cited by 13 publications

(5 citation statements)

References 16 publications

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“…Subsequently, all essential properties can be tailored in wide ranges by using different combinations of materials, crystallographic orientations (cuts), and microstructures. 15 So far, KNbO 3 thin films can be synthesized by the following methods: metalorganic chemical vapor deposition (MOCVD), [16][17][18][19] pulsed-laser deposition, 10,20-25 sputtering, 26,27 liquid-phase epitaxy, [28][29][30] and solgel. [31][32][33] All these synthesis routes share similar disadvantages of high-temperature processing, requiring temperatures ranging between 600 °C and over 900 °C to obtain a crystalline KNbO 3 phase.…”

Section: Introductionmentioning

confidence: 99%

“…The high synthesis temperatures cause typical problems such as difficulties to control potassium stoichiometry due to high volatilization of potassium oxide, interdiffusion between film and the substrate, 20,21,24 formation of interphase layers (particularly in the case of using MgO substrate), 21,24 and multidomain formation during cooling to room temperature. 16,[20][21][22][23]27,29,30 The presence of pyrochlore and/or amorphous phases, as well as porosity, was reported particularly for the KNbO 3 films synthesized by the sol-gel method. 32,33 In addition, liquid-phase epitaxy (LPE) is not well suited for films with thickness under 1 µm.…”

Section: Introductionmentioning

confidence: 99%

“…32,33 In addition, liquid-phase epitaxy (LPE) is not well suited for films with thickness under 1 µm. 30 In other words, all previously used methods to synthesize KNbO 3 films yielded films with more or less deteriorated properties due to the high synthesis temperatures. Therefore, development of a low-temperature fabrication of KNbO 3 thin films, particularly at temperatures lower than the tetragonal to orthorhombic phase transformation of 225 °C appears to be necessary in order to realize multiple potential applications of the KNbO 3 films.…”

Section: Introductionmentioning

confidence: 99%

“…So far, KNbO 3 thin films can be synthesized by the following methods: metalorganic chemical vapor deposition (MOCVD), − pulsed-laser deposition, ,− sputtering, , liquid-phase epitaxy, − and sol−gel. − All these synthesis routes share similar disadvantages of high-temperature processing, requiring temperatures ranging between 600 °C and over 900 °C to obtain a crystalline KNbO 3 phase. The high synthesis temperatures cause typical problems such as difficulties to control potassium stoichiometry due to high volatilization of potassium oxide, interdiffusion between film and the substrate, ,, formation of interphase layers (particularly in the case of using MgO substrate), , and multidomain formation during cooling to room temperature. ,− ,,, The presence of pyrochlore and/or amorphous phases, as well as porosity, was reported particularly for the KNbO 3 films synthesized by the sol−gel method. , In addition, liquid-phase epitaxy (LPE) is not well suited for films with thickness under 1 μm …”

Section: Introductionmentioning

confidence: 99%

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Synthesis of Potassium Niobiate (KNbO₃) Thin Films by Low-Temperature Hydrothermal Epitaxy

Suchanek

2004

Chem. Mater.

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Orthorhombic KNbO 3 thin films were deposited on SrTiO 3 (100) and LiTaO 3 (001) substrates by low-temperature hydrothermal epitaxy at 180-210°C using aqueous solutions containing Nb 2 O 5 and KOH. The films were thoroughly characterized by X-ray diffraction, Rutherford backscattering, and scanning electron microscopy. The KNbO 3 films were uniformly distributed on the entire substrate area, exhibited high stoichiometry, and did not show evidence of interdiffusion or chemical reaction at the film/substrate interface. Their microstructures were determined by the substrate used, the synthesis temperature, and the concentration of the reactants. The KNbO 3 films on SrTiO 3 (100) substrates with thickness of 45 nm to 1.28 µm were smooth and transparent, with microstructures strongly suggesting single crystal growth mechanism. They were pure orthorhombic phase with (011) orientation and probably single-domain. Conversely, the KNbO 3 films with higher thickness (>3.5 µm) exhibited very rough microstructure with textured columnar grains. Such films were also orthorombic but with mixed (100)/(011) orientation. This work demonstrated for the first time deposition of heteroepitaxial KNbO 3 films on single-crystal substrates using low-temperature hydrothermal epitaxy in a well-defined range of synthesis conditions. The low synthesis temperatures, which are below the 225°C phase transition temperature of KNbO 3 , resulted in formation of films that appear to exhibit improved features as compared to the films prepared by high-temperature processing. IntroductionPotassium niobiate (KNbO 3 ) is a very promising material for surface acoustic wave (SAW) devices and high-performance bulk-wave transducers. 1 The elctromechanical coupling coefficient (k 2 ) of the surface wave in a single-crystal KNbO 3 can be as high as 53%, which is one order of magnitude larger than that of LiNbO 3 . 2 The bandwidth is about 20% and insertion losses are 2-6 dB. 2 The acoustic wave velocities in KNbO 3 are 3500-7500 m/s 3 and the temperature coefficient of frequency (TCF) ranges between 0 and 170 ppm/K depending upon crystallographic orientation. 2 The KNbO 3 exhibits large piezoelectric nonlinearity. The 45°r otated Y-cut X-propagated KNbO 3 has 25 dB larger efficiency than Y-Z LiNbO 3 ; thus the KNbO 3 single crystal is considered as a promising material for SAW elastic convolvers with super high efficiency and process gain. 4 In addition to excellent piezoelectric properties, the KNbO 3 has a large electrooptic coefficient, high nonlinear optical coefficient, and excellent photorefractive characteristics 5 that make it a very promising candidate for optical applications such as optical waveguides, frequency doublers, 6 intensity modulators, 7

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Synthesis of Potassium Niobiate (KNbO₃) Thin Films by Low-Temperature Hydrothermal Epitaxy

Suchanek

2004

Chem. Mater.

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“…The growth of barium-doped KT was already reported from our laboratory [10,11], but to our knowledge there are no reports on the investigations on the growth of bulk homogeneously-doped KT:Ba crystals. The investigations on the growth of KTN and KNTN thin films have been reported by several authors [12][13][14][15][16][17][18]. For the practical realization of optical devices such as waveguides and microresonators wide area (5 Â 5 mm 2 ) with flat as grown epilayers of uniform composition are needed.…”

Section: Introductionmentioning

confidence: 98%