掺铈铌酸锂晶体的生长和表征(英文)

Growth and Characterization of Ce-Doped Lithium Niobate Crystal

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 photoelectronspectroscopy,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。

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 LiNbO3 except for the little wave number shifting of A1(TO4) mode and shoulder linewidth of A1(TO1) mode,indicating that the Ce ions mainly occupy the Nb-sites in the as-grown crystal.