The Structure And Optical Properties Of Potassium Tantalite Niobate Films

In recent years, with the development of thin film manufacturing technology,the research and application of electro-optical functional material thin film were promoted in the field of optical holographic storage, optical information phase conjugation, electro-optic switch and microelectronic integration. Tantalum potassium niobate(KTax Nb1-x O3, KTN) crystal is a classic material with ABO3 perovskite structure, and its excellent performance in the second electro-optical and ferroelectric properties make it one of the best electro-optical information functional materials. In this paper, tantalum potassium niobate was investigated, in which the value of Ta/Nb is 1:1. The structure and elastic properties of the ordered KTN crystal,structure and optical properties of KTN crystal with potassium or oxygen vacancy and structure and optical properties of the ordered KTN and KLTN thin-films were studied by first-principles based on density functional theory. The KTN thin-films with high orientation were prepared on Pt and quartz substrates by pulsed laser deposition(PLD). With the help of the Double-beam UV-Vis spectrophotometer and ellipsometer, the absorption, transmittance and refraction spectra analyzing of the KTN thin film were delivered.The models of the ordered KTN crystal, KTN crystal with potassium or oxygen vacancy, the ordered KTN and KLTN thin-films were built in the Material Studio software platform. The structure, elastic and optical properties of these models were calculated by local density approximation(LDA). The influences of the ordered structure and the defect structure on the properties of the materials were discussed.The optical properties of KTN and KLTN thin films along(100) crystal orientation were explored.By using pulsed laser deposition, the(100) crystal orientation up to 94.62 %high quality KTN thin film on Pt substrate were prepared. The absorption and transmission spectra curve of the KTN thin film were measured by the Double-beam UV-Vis spectrophotometer, where the absorption edge of KTN thin films was foundnear 300 nm and transmittance of thin film is up to 80 % wavelength ranges from320 nm to 900 nm. We analyze the refractive index and extinction coefficient of the KTN film with the help of ellipsometer and reach a conclusion that the film refractive index and the extinction coefficient decrease with the increase of wavelength in the visible light band, which meet the Cauchy model well.