As a kind of excellent piezoelectric material, lithium niobate (LiNbO3) has been widely used for surface acoustic wave (SAW) devices. On a self-designed automatic diameter control system, large diameter (6 inch) LiNbO3 crystals without cracks are successfully grown by choosing a suitable temperature gradient, starting composition, and growth parameters with the Czochralski method. The constituent phases of the LiNbO3 crystals and their polycrystalline precursor are determined by X-ray powder diffraction, and the Li content along the crystal growth direction is determined by Raman scattering spectroscopy. The temperature gradient and growth parameters that influence the growth of the large diameter crystals are discussed in detail. The chemical analyses reveal that the 6 inch LiNbO3 crystals have high homogeneity. The average Curie temperature is 1143.04 ± 1.3 °C, and the piezoelectric coefficient d22 is up to 19.8 pC N−1. The specific heat (Cp), thermal expansion coefficients (αa and αc), thermal diffusion coefficients (λa and λc), and thermal conductivities (κa and κc) of the LiNbO3 crystals are also determined.

The growth and characterization of six inch lithium niobate crystals with high homogeneity

https://onlinelibrary.wiley.com/doi/pdf/10.1002/adpr.202000149

Nanocomposite-Seeded Epitaxial Growth of Single-Domain Lithium Niobate Thin Films for Surface Acoustic Wave Devices

/pdf/experimental-investigation-of-impurities-and-their-effect-on-28gkupgh4i.pdf

Experimental Investigation of Impurities and Their Effect on Acousto-electric Properties of Lithium Niobate

An attractive combination of piezoelectric and optical properties has made lithium niobate one of the most extensively studied materials. Nowadays, application of these crystals in various fields such as acoustic wave propagation, electro-optic light modulation, optical second harmonic generation and parametric oscillation demands the bulk single crystal production. Solid State Physics Laboratory has grown large diameter (2 inch) lithium niobate (LiNbO3) single crystals successfully. Colourless, transparent, good optical quality crystals weighing up to 1.3 kg have been grown by Czochralski method. A computer controlled crystal puller equipped with R.F. heating has been used to pull these crystals from melt. An after heater wound with Kanthal A1 wire has been used. The growth parameter to develop crack free, good optical quality crystals have been optimized and will be discussed in detail. Grown crystals were sliced into 1 mm thick wafer and polished. Grown crystal surfaces were observed through o...

R. Thyagarajan

Papers

Growth of large diameter lithium niobate single crystals by czochralski method