掺铈铌酸锂晶体的生长和表征

采用提拉法生长了掺Ce的同成分LiNbO3（Ce：CLN）晶体。X射线粉末衍射表明,掺杂并不影响晶体结构,其空间群为R3c。采用X射线荧光光谱分析方法,计算得到铈离子的有效分凝系数为0.4。室温下,晶体在700～3500nm波段的透过率达75%。利用X射线光电子谱（X-ray photoelectron spectroscopy,XPS）和Raman光谱分别表征了铈离子对铌酸锂的电子和声子结构的影响。XPS结果表明,铌离子仅存在纯的＋5价,铈离子由于浓度较小,未检测到信号。Raman光谱结果显示,除Ce：CLN晶体的A1（TO4）模波数和A1（TO1）模半峰宽较纯的LiNbO3晶体发生明显变化外,其余模都与其基本一致,表明铈离子主要进入晶格的Nb位置。

Growth and Characterization of Ce-Doped Lithium Niobate Crystal

The Ce-doped congruent lithium niobabe (Ce:CLN) single crystal was grown by the Czochralski method. The result by X-ray diffraction shows that the as-grown crystal exhibits a single-phase (R3c) LN, and the doping of Ce ions into the CLN crystal lattice does not affect its basic crystal structure. The effective segregation coefficient of Ce ions determined by X-ray fluorescence analysis was 0.4. At room temperature, the transmittance of as-grown crystal was 75% in the range of 700–3 500 nm. The influence of Ce incorporation into CLN crystal lattice on the electronic and phonon structure was analyzed by X-ray photoelectron spectroscopy (XPS) and Raman scattering spectroscopy, respectively. The XPS results show that Nb ions only exhibit a pure +5 valence, and the signal of Ce ions is not recorded due to its low concentration. The Raman spectrum results show that the modes of as-grown Ce:CLN are similar to those of pure LiNbO 3 except for the little wave number shifting of A 1 (TO 4 ) mode and shoulder linewidth of A 1 (TO 1 ) mode, indicating that the Ce ions mainly occupy the Nb-sites in the as-grown crystal.