The Study Of The Spectral Properties Of Zn Ion Implanted Lithium Niobate Crystals

In recent years, the study of Zn nanoparticles materials and Li Nb O3 materials has become a hot topic in the fields of material and optics. Since 1980 s, it was discovered that metal nanoparticle composite materials by implanting metal ions into Li Nb O3 crystal have many different optical properties compared with the pure Li Nb O3 crystal. The implanted Li Nb O3 crystal has been widely used because of these new optical properties, especially in the terahertz field. In this thesis, three different doses of Zn ions were implanted into Li Nb O3 substrates by using a metal vapor vacuum ion source. And subsequently the samples were annealed in oxygen atmosphere at 600℃. The Zn ions implanted samples were characterized by X-ray photoelectron spectroscopy(XPS) and X-ray diffraction(XRD) techniques, respectively. And by using THz time-domain spectroscopy(THz-TDS), UV spectrophotometer and Fourier transform infrared spectroscopy, the optical spectral properties of samples were also studied in the THz, ultraviolet and infrared wave ranges.The main content and the results were shown as follows:1. Three different doses of Zn ions(0.6×1017 ions/cm2, 1.2×1017 ions/cm2 and 1.8×1017 ions/cm2) were implanted into Li Nb O3 substrates by using a metal vapor vacuum ion source. And subsequently the samples were annealed in a 1200℃ vacuum furnace in oxygen atmosphere, and kept 600℃ for one hour. The Zn nanoparticles were oxidized into Zn O nanoparticles.2. The Zn ions implanted samples were characterized by XPS and XRD techniques, respectively. The results of XPS experiments show that the Zn ions have been successfully implanted into the Li Nb O3 substrate. And the size of Zn particles is in the nanometer level. The Zn ions in the sample surface are nearly Gaussian distribution, so that Zn ions in the annealed samples are diffused to the surface or inside. The results of XRD experiments show that Zn O particles in the sample have two kinds of crystal planes.3. In the extraction process of the optical parameters by using the THz-TDS, the4. The transmission properties and optical parameters of samples were analyzed by the THz-TDS. The Experimental results show that the transmission of the Zn ions samples is enhanced due to Zn ion implantation in certain frequency ranges.5. The absorption coefficient of samples in the ultraviolet and infrared wave ranges was studied based on UV spectrophotometer and Fourier transform infrared spectroscopy. The experimental results show that Zn ion implantation made the absorption coefficient and main absorption peaks of samples occur in the red shift. Due to the different ions radius between Zn and the Li, Nb, the main absorption peaks shift slightly. Moreover, the transmittance of x-cut Li Nb O3 crystals is enhanced duo to Zn ion implantation, but the transmittance of z-cut Li Nb O3 crystals decrease.